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FIELD OF THE INVENTION
[0001] The present disclosure generally relates to processes useful in making strong, soft, absorbent paper products. More particularly, the present disclosure relates to papermaking processes using belts formed from a resinous framework and a reinforcing structure having embedded sensors that provide process feedback that can provide a significant increase in the operating lifetime of the papermaking belt.
BACKGROUND OF THE INVENTION
[0002] Processes for the manufacturing of paper products for use in tissue, toweling and sanitary products generally involve the preparation of an aqueous slurry of paper fibers and then subsequently removing the water from the slurry while contemporaneously rearranging the fibers in the slurry to form a paper web. Various types of machinery can be employed to assist in the dewatering process.
[0003] The processes to manufacture these paper products use a paper slurry that is fed onto the top surface of a traveling endless belt that serves as the initial papermaking surface of the machine. These papermaking belts or fabrics carry various names depending on their intended use. Fourdrinier wires, also known as Fourdrinier belts, forming wires, or forming fabrics are used in the initial forming zone of the papermaking machine. Dryer fabrics carry the paper web through the drying operation of the papermaking machine.
[0004] One particular papermaking belt utilizes a foraminous woven member surrounded by a hardened photosensitive resin framework. The resin framework has a plurality of discrete, isolated, channels known as “deflection conduits” disposed therein. The process to manufacture a paper product can involve the steps of associating an embryonic web of papermaking fibers with the top surface of the papermaking belt, deflecting the paper fibers into the deflection conduits, and applying a vacuum or other fluid pressure differential to the web from the backside (machine-contacting side) of the papermaking belt. This process made it finally possible to create paper having certain desired preselected characteristics.
[0005] Although the aforementioned process produces suitable papermaking belts and results in superior formed paper products, it has been found that the papermaking manufacturing environment severely limits the lifetime of these papermaking belts. This could be attributed to the inability to measure certain key physical parameters of the papermaking belt during use. By way of example, the equipment used in the manufacture of paper products subjects the papermaking belt to extreme temperatures, bending moments, tensions, stress, strain, pH, wear, and the like. Each of these factors has been found to severely limit the life of the papermaking belts by causing micro-fractures to occur in the hardened resins that form the surface of the papermaking belt as well as fractures due to oxidation and decay of the resin itself. Without desiring to be bound by theory, resin loss is believed to be the primary cause of belt failure. This is particularly true of papermaking systems that incorporate the use of high temperature pre-dryers and Yankee drying drums. Additionally, the high pressures experienced by the papermaking belt in process nips (formed between pressure rolls) and vacuum slots, as well as process abrasion points (e.g., while traversing vacuum boxes and the like) and stresses introduced by misaligned process equipment have been linked to premature papermaking belt failures.
[0006] The significance of the difficulties experienced by users of these papermaking belts is exacerbatingly increased by the relatively high cost of the papermaking belts themselves. For example, manufacturing a foraminous woven element that is incorporated into these belts requires expensive textile processing operations, including the use of large and costly looms. Also, substantial quantities of relatively expensive filaments are incorporated into these foraminous woven elements. The cost of these papermaking belts is further increased when filaments having high heat resistance properties are used. These special filaments are generally necessary for papermaking belts that pass through various high temperature drying operations.
[0007] In addition to the cost of the belt itself, the decay and/or failure of a papermaking belt can also have serious implications on the efficiency of the papermaking process and the paper products so produced. A high frequency of paper machine belt failures can substantially affect the economies of a paper manufacturing business due to the loss of the use of the expensive papermaking machinery (that is, the machine “downtime”) during the time a replacement belt is being fitted on the papermaking machine.
[0008] Therefore, a need exists for an improved papermaking belt, a method of making a papermaking belt, and an ability to monitor the physical condition of a papermaking belt during use in the production of paper products that can eliminate the foregoing problems. In short, the ability to measure the physical condition of the papermaking belt made by the prior processes during use can provide for real-time in situ feedback into the papermaking process that can stimulate process changes necessary to produce quality paper products and simultaneously increase papermaking belt life.
SUMMARY OF THE INVENTION
[0009] The present disclosure provides for a process for adjusting a papermaking process for producing rolls of convolutely wound web material having a machine direction (MD) and a cross-machine direction (CD) coplanar and orthogonal thereto. The process improves the operating life of a papermaking belt used therefor. The process for adjusting the papermaking process comprising the steps of: (a) providing a foraminous papermaking belt having a discrete measuring device disposed therein; (b) providing a papermaking machine, said papermaking machine having at least one heating process, said heating process having a heating process set-point, said foraminous papermaking belt being integral with said papermaking machine; (c) depositing an aqueous dispersion of papermaking fibers upon a surface of said papermaking belt; (d) dewatering said aqueous dispersion of papermaking fibers while disposed upon said surface of said foraminous papermaking belt by causing said foraminous papermaking belt and said aqueous dispersion of papermaking fibers disposed thereon to traverse through said heating process, said discrete measuring device measuring a temperature of said heating process; (e) causing said foraminous papermaking belt to traverse past a receiver, said receiver being in wireless communicating engagement with said discrete measuring device when said discrete measuring device is proximate said receiver, said discrete measuring device being capable of wirelessly transmitting information to said receiver, said information comprising data relating to said temperature of said heating process during said dewatering step; and, (f) changing said heating process set-point according to said measurement of said temperature of said heating process of said dewatering step.
[0010] The present disclosure also provides for adjusting a papermaking process for producing rolls of convolutely wound web material having a machine direction (MD) and a cross-machine direction (CD) coplanar and orthogonal thereto. The process improves the operating life of a papermaking belt used therefor. The process for adjusting the papermaking process comprising the steps of: (a) providing a foraminous papermaking belt having a discrete measuring device disposed therein; (b) providing a papermaking machine, said papermaking machine having at least one compressionary process, said compressionary process having a compressionary process set-point, said foraminous papermaking belt being integral with said papermaking machine; (c) depositing an aqueous dispersion of papermaking fibers upon a surface of said papermaking belt; (d) dewatering said aqueous dispersion of papermaking fibers while disposed upon said surface of said foraminous papermaking belt by causing said foraminous papermaking belt and said aqueous dispersion of papermaking fibers disposed thereon to traverse through said compressionary process, said discrete measuring device measuring at least one compressionary force of said compressionary process; (e) causing said foraminous papermaking belt to traverse past a receiver, said receiver being in wireless communicating engagement with said discrete measuring device when said discrete measuring device is proximate said receiver, said discrete measuring device being capable of wirelessly transmitting information to said receiver, said information comprising data relating to said pressure of said compressionary process during said dewatering step; and, (f) changing said compressionary process set-point according to said measurement of said pressure of said compressionary process of said dewatering step.
[0011] The present disclosure further provides for a process for adjusting a papermaking process for producing rolls of convolutely wound web material having a machine direction (MD) and a cross-machine direction (CD) coplanar and orthogonal thereto. The process improves the operating life of a papermaking belt used therefor. The process for adjusting the papermaking process comprising the steps of: (a) providing a foraminous papermaking belt having a discrete measuring device disposed therein; (b) providing a papermaking machine, said papermaking machine having at least one papermaking belt deformation process, said papermaking belt deformation process having a papermaking belt deformation characteristic set-point, said foraminous papermaking belt being integral with said papermaking machine; (c) depositing an aqueous dispersion of papermaking fibers upon a surface of said papermaking belt; (d) dewatering said aqueous dispersion of papermaking fibers while disposed upon said surface of said foraminous papermaking belt by causing said foraminous papermaking belt and said aqueous dispersion of papermaking fibers disposed thereon to traverse through said papermaking belt deformation process, said discrete measuring device measuring at least one papermaking belt deformation characteristic of said papermaking belt deformation process; (e) causing said foraminous papermaking belt to traverse past a receiver, said receiver being in wireless communicating engagement with said discrete measuring device when said discrete measuring device is proximate said receiver, said discrete measuring device being capable of wirelessly transmitting information to said receiver, said information comprising data relating to said papermaking belt deformation characteristic of said papermaking belt deformation process during said dewatering step; and, (f) changing said papermaking belt deformation characteristic process set-point according to said measurement of said pressure of said papermaking belt deformation process of said dewatering step.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic representation of one embodiment of a continuous papermaking machine useful in carrying out the process of this disclosure;
[0013] FIG. 2 is a plan view of a portion of an embodiment of the improved papermaking belt of the present disclosure;
[0014] FIG. 3 is an enlarged cross-sectional view of the portion of the improved papermaking belt shown in FIG. 2 taken along line 3 - 3 ;
[0015] FIG. 4 is an enlarged cross-sectional view of the portion of the improved papermaking belt shown in FIG. 2 taken along line 4 - 4 ;
[0016] FIG. 5 is an enlarged plan view of a portion of an exemplary woven multi-layer reinforcing structure suitable for use with the improved papermaking belt;
[0017] FIG. 6 is a schematic representation of the basic apparatus for making the papermaking belt of the present disclosure;
[0018] FIG. 7 is an enlarged schematic cross-sectional view of a portion of the casting surface of a process for making the papermaking belt of the present disclosure showing the working surface, barrier film, reinforcing structure, resin, and mask.
DETAILED DESCRIPTION
[0019] In papermaking, the term “machine direction” (MD) refers to that direction which is parallel to the flow of the paper web through the equipment. The “cross-machine direction” (CD) is perpendicular to the machine direction. The “Z-direction” refers to that direction that is orthogonal to both the MD and CD.
The Improved Papermaking Belt
[0020] In the representative papermaking machine illustrated in FIG. 1 , the papermaking belt 10 (or belt 10 ) of the present disclosure can take the form of an endless belt. In FIG. 1 , the papermaking belt 10 carries a paper web (“fiber web” or the like) in various stages of its formation and travels in the direction indicated by directional arrow B around the papermaking belt return rolls 19 a , 19 b , impression nip roll 20 , papermaking belt return rolls 19 c , 19 d , 19 e and 19 f , and emulsion distributing roll 21 . The loop the papermaking belt 10 travels around includes a means for applying a fluid pressure differential to the paper web, such as vacuum pickup shoe 24 a and multi-slot vacuum box 24 . In FIG. 1 , the papermaking belt can also travel around a pre-dryer such as blow-through dryer 26 , and pass between a nip formed by the impression nip roll 20 and a Yankee dryer drum 28 . Although an embodiment of the present disclosure is in the form of an endless belt, the present disclosure can be incorporated into numerous other forms.
[0021] The overall characteristics of the papermaking belt 10 of the present disclosure are shown in FIGS. 2-4 . The papermaking belt 10 of the present disclosure is generally comprised of two primary elements: a framework 32 and a reinforcing structure 33 . In one non-limiting example, framework 32 can be a hardened polymeric photosensitive resin. In one embodiment, the papermaking belt 10 is provided as an endless belt having two opposed surfaces which are referred to herein as the paper-contacting side 11 and a textured backside or simply, backside 12 . The backside 12 of the papermaking belt 10 contacts the machinery employed in the papermaking operation, such as vacuum pickup shoe 24 a and multi-slot vacuum box 24 . The framework 32 has a first surface 34 , a second surface 35 opposite the first surface 34 , and conduits 36 extending between the first surface 34 and the second surface 35 . The first surface 34 of the framework 32 contacts the fiber webs to be dewatered, and defines the paper-contacting side 11 of the belt. The conduits 36 extending between the first surface 34 and the second surface 35 channel water from the fiber web that rests on the first surface 34 to the second surface 35 and provides areas into which the fibers of the fiber web can be deflected into and rearranged. FIG. 2 shows that the network 32 a can comprise the solid portion of the framework 32 that surrounds the conduits 36 to define a net-like pattern.
[0022] As shown in FIG. 2 , the openings 42 of the conduits 36 can be arranged in a preselected pattern in the network 32 a . FIG. 2 shows that the first surface 34 of the framework 32 has a paper side network 34 a formed therein which surrounds and defines the openings 42 of the conduits 36 in the first surface 34 of the framework 32 . The second surface 35 of the framework 32 has a backside network 35 a that surrounds and defines the openings 43 of the conduits 36 in the second surface 35 of the framework 32 . FIGS. 3-4 provide that the reinforcing structure 33 of the papermaking belt 10 is at least partially surrounded by, enveloped, embedded, and/or encased within the framework 32 . More specifically, the reinforcing structure 33 is positioned between the first surface 34 of the framework 32 and at least a portion of the second surface 35 of the framework 32 . FIGS. 3 and 4 also show that the reinforcing structure 33 has a paper-facing side 51 and a machine-facing side 52 opposed thereto. As shown in FIG. 2 , the reinforcing structure 33 has interstices 39 and a reinforcing component 40 . The reinforcing component 40 comprises the portions of the reinforcing structure exclusive of the interstices 39 (that is, the solid portion of the reinforcing structure 33 ). A plurality of measurement device(s) 50 (also referred to herein as measuring device(s) 50 ) can be disposed within the framework 32 and can be incorporated into or upon the reinforcing structure 33 . Measurement devices 50 , their incorporation into a papermaking belt, and their usefulness will be discussed infra.
[0023] The reinforcing component 40 is generally comprised of a plurality of structural components 40 a . FIGS. 3-4 show that the second surface 35 of the framework 32 has a backside network 35 a with a plurality of passageways 37 . The passageways 37 allow air to enter between the backside surface 12 of the papermaking belt 10 and the surfaces of the vacuum dewatering equipment employed n the papermaking process (such as vacuum pickup shoe 24 a and vacuum box 24 ) when a vacuum is applied by the dewatering equipment to the backside 12 of the belt to deflect the fibers into the conduits 36 of the belt 10 .
[0024] The paper-contacting side 11 of the belt 10 shown in FIGS. 1-4 is the surface of the papermaking belt 10 which contacts the paper web which is to be dewatered and rearranged into the finished product. The paper-contacting side 11 of the belt 10 may also be referred to as the “embryonic web-contacting surface” of the belt 10 . As shown in FIGS. 2-4 , the paper-contacting side 11 of the belt 10 is generally formed entirely by the first surface 34 of the framework 32 .
[0025] As shown in FIG. 1 , the backside 32 is the surface which travels over and is generally in contact with the papermaking machinery employed in the papermaking process.
[0026] The reinforcing structure 33 is shown in FIGS. 2-4 and in isolation in FIG. 5 . The reinforcing structure 33 strengthens the resin framework 32 and has suitable projected open area to allow the vacuum dewatering machinery employed in the papermaking process to adequately perform its function of removing water from partially-formed webs of paper and to permit water removed from the paper web to pass through the papermaking belt 10 . The reinforcing structure 33 can comprise a woven element (also sometimes referred to herein as a woven “fabric”), a nonwoven element, a screen, a net (for instance, thermoplastic netting), a scrim, or a band or plate (made of metal or plastic or other suitable material) with a plurality of holes punched or drilled in it provided the reinforcing structure 33 adequately reinforces the framework 32 and has sufficient projected open area. Preferably, the reinforcing structure 33 comprises a foraminous woven element.
[0027] Generally, as shown in FIGS. 2-5 , the reinforcing structure 33 comprises a reinforcing component 40 and a plurality of interstices 39 . The reinforcing component 40 is the portion of the reinforcing structure 33 exclusive of the interstices 39 . In other words, the reinforcing component 40 is the solid portion of the reinforcing structure 33 . The reinforcing component 40 is comprised of one or more structural components 40 a . “Structural components” refers to the individual structural elements that comprise the reinforcing structure 33 .
[0028] The interstices 39 allow fluids (e.g., water removed from the paper web) to pass through the belt 10 . The interstices 39 may form any pattern in the reinforcing structure 33 . The pattern formed by the interstices 39 should be contrasted with the preselected pattern formed by the conduit openings.
[0029] As shown in FIGS. 3-4 , the reinforcing structure 33 has two sides. These are the paper-facing side (or “paper support side”) 51 that faces the fiber webs to be dewatered, and the machine-facing side (or “roller contact side”) generally designated 52 opposing the paper-facing side. As shown in FIGS. 3 and 4 , the reinforcing structure 33 is positioned between the first surface 34 of the framework 32 and at least a portion of the second surface 35 of the framework 32 .
[0030] The structural components 40 a of a woven reinforcing structure can comprise yarns, strands, filaments, or threads. It is also to be understood that the above terms (yarns, strands, etc.) could comprise not only monofilament elements, but also multifilament and/or multi-component (e.g., bi-component) elements. Many types of woven elements are suitable for use as a reinforcing structure 33 in the papermaking belt 10 of the present disclosure. Suitable woven elements include foraminous monolayer woven elements (having a single set of strands running in each direction and a plurality of openings therebetween) such as the reinforcing structure 33 shown in FIG. 5 .
[0031] The papermaking belt 10 comes under considerable stress in the machine direction due to the repeated travel of the belt 10 over the papermaking machinery in the machine direction and also due to the heat transferred to the belt by the drying mechanisms employed in the papermaking process. Such heat and stress can cause the papermaking belt to stretch. If the papermaking belt 10 stretches significantly, its ability to serve its intended function of carrying a paper web through the papermaking process can become diminished to the point of uselessness. If significant tension is applied to the papermaking belt 10 during manufacture of the papermaking belt 10 itself or during use of the papermaking belt 10 on a paper machine, mechanical failure can occur (i.e., the belt can rip or can be caused to sufficiently narrow (Poisson effect)).
[0032] To be suitable for use as a reinforcing structure, a multilayer woven element preferably has some type of structure that provides for reinforcement of the machine direction yarns 53 . In other words, the multilayer fabric should have increased fabric stability in the machine-direction.
[0033] As shown in FIGS. 2-5 , a preferred reinforcing structure 33 is a multilayer woven element that has a single layer yarn system with yarns which extend in a first direction and a multiple layer yarn system with yarns which extend in a second direction normal to the first direction. In the preferred reinforcing structure 33 , the first direction is the cross-machine direction. The yarns that extend in the first direction comprise the weft yarns 54 . The multiple layer yarn system extends in the machine direction. Fabrics having multiple machine direction warp yarns are preferred, however, because the additional strands run in the direction which is generally subject to the greatest stresses.
[0034] While the specific materials of construction of the warp yarns and weft yarns can vary, the material comprising the yarns should be such that the yarns will be capable of reinforcing the resinous framework and sustaining stresses as well as repeated heating and cooling without excessive stretching. Suitable materials from which the yarns can be constructed include polyesters, polyamides, high heat resistant materials such as KEVLAR™, NOMEXTm, combinations thereof, and any other materials which are known for use in papermaking fabrics.
[0035] Any convenient cross-sectional dimensions (or size) of the yarns can be used as long as the flow of air and water through the conduits 36 is not significantly hampered during the paper web processing and as long as the integrity of the papermaking belt 10 maintained. The cross-sectional shapes of the yarns in the different layers and yarn systems can also vary between the layers and yarn systems.
[0036] The reinforcing structure 30 can have a first portion P 01 of the reinforcing component 40 that has a first opacity 0 1 , and a second portion P 02 of the reinforcing component 40 that has a second opacity 0 2 . The two opacities 0 1 and 0 2 can be related such that the second opacity 0 2 is less (that is, relatively less opaque) than the first opacity 0 1 . The first opacity 0 1 should be sufficient to substantially prevent the curing of a photosensitive resinous material, if such a material is used to form the framework 32 , when that photosensitive resinous material is in its uncured state and the first portion P 01 is positioned between the photosensitive resinous material and a source of actinic radiation.
[0037] The framework 32 can be formed by manipulating a mass of material, generally in liquid form, so that the material, when in solid form, at least partially surrounds the reinforcing structure 33 so that the reinforcing structure 33 is positioned between the first surface 34 and at least a portion of the second surface 35 of the framework 32 . The material can be manipulated so that the framework 32 has a plurality of conduits 36 or channels that extend between the first surface 34 and the second surface 35 of the framework 32 . The material can also be manipulated so that the first surface has a paper side network 34 a formed therein which surrounds and defines the openings of the conduits 36 in the first surface 34 of the framework 12 . In addition, the material can be manipulated so that the second surface 35 of the framework 32 has a backside network 35 a with passageways 37 , distinct from the conduits 36 .
[0038] The mass of material which is manipulated to form the framework 32 can be any suitable material, including thermoplastic resins and photosensitive resins, but the preferred material for use in forming the framework 32 of the present disclosure is a liquid photosensitive polymeric resin. Likewise, the material chosen can be manipulated in a wide variety of ways to form the desired framework 32 , including mechanical punching or drilling, curing the material by exposing it to various temperatures or energy sources, or by using a laser to cut conduits. The method of manipulating the material which will form the framework 32 , of course, can depend on the material chosen and the characteristics of the framework 32 desired to be formed from the mass of material. Preferably, the photosensitive resin is manipulated by controlling the exposure of the liquid photosensitive resin to light of an activating wavelength.
[0039] Since the reinforcing structure 33 is positioned between the first surface 34 and at least a portion of the second surface 35 of the framework 32 , the second surface 35 of the framework 32 can either, completely cover the reinforcing structure 33 , cover only a portion of the reinforcing structure 33 or, cover no portions of the reinforcing structure 33 and lie entirely within the interstices 39 of the reinforcing structure 33 .
[0040] The conduits 36 have a channel portion 41 which lies between the conduit openings 42 and 43 . These channel portions 41 are defined by the walls 44 of the conduits 36 . FIGS. 2-4 show that the holes or channels 41 formed by the conduits 36 extend through the entire thickness of the papermaking belt 10 . In addition, as shown in FIG. 2 , the conduits 36 are generally discrete. By “discrete”, it is meant that the conduits 36 form separate channels, which are separated from each other by the framework 32 . The conduits 36 are described as being “generally” discrete, however, because the conduits 36 may not be completely separated from each other along the second surface 35 of the framework 32 when passageways 37 are present in the backside network 35 a.
[0041] It is preferred that the passageways 37 and the irregularities 38 are distinct from the conduits 36 which pass through the framework 32 . By “distinct” from the conduits, it is meant that the passageways 37 and the irregularities 38 which comprise departures from the otherwise smooth and continuous backside network 35 a of the framework 32 are to be distinguished from the holes 41 formed by the conduits 36 . In other words, the holes 41 formed by the conduits 36 are not intended to be classified as passageways or surface texture irregularities.
[0042] Referring again to FIG. 1 , belt 10 carries an embryonic web 18 on the first surface. As shown, a portion of belt 10 passes over a single slot 24 d of a vacuum box 24 . In operation, a vacuum is applied from a vacuum source (not shown), which exerts pressure on the belts and the embryonic webs 18 in the direction of the arrows shown. The vacuum removes some of the water from the embryonic web 18 and deflects and rearranges the fibers of the embryonic web into the conduits 36 of the framework 32 .
[0043] The measurement devices 50 and an associated reading device 60 (also referred to herein as receiver 60 ) (the receiver 60 being efficaciously disposed about the papermaking process) are preferably configured to measure or monitor any physical characteristics of the papermaking belt 10 during the manufacture of paper products. The measurement devices 50 may also be configured to measure and monitor physical characteristics for controlling and monitoring the papermaking process. The characteristics that can be measured can include, e.g. belt temperature, belt deformation (e.g., tension, compression, bending moment, stress, and/or strain), belt and/or process pressure, belt acceleration (vibration), moisture, speed, pH, and the like. The measurement devices 50 may transmit measurement data when proximate to the receiver 60 , which may further communicate any measurement data to a control unit and/or a data acquisition system capable of processing and/or storing such measurement data. The measurement devices 50 may comprise a transmitter or a transceiver for communicating the measurement data wirelessly to a receiver 60 . The measurement devices 50 may be remotely-read untouchably by receiver 60 by means of electromagnetic radiation. Depending on the wavelength, the electromagnetic radiation used can include: radio waves, microwaves, infrared radiation, light, ultraviolet radiation, X-ray radiation, gamma radiation, and the like. Exemplary and suitable measurement devices can include those developed by the Wireless Identification and Sensing Platform of the University of Washington. Suitable reading devices 60 are the model S9028PCL UHF receiver manufactured by Laird Technologies.
[0044] Additionally, measurement devices 50 can be provided as microelectromechanical (MEMS), nanoelectromechanical (NEMS) systems, combinations thereof, and the like. Both MEMS and NEMS can be formed from graphene, at least in part, although other materials may be used alternatively as would be understood by those of skill in the art. As would be understood by one of skill in the art, graphene is a single atomic layer of carbon and is the strongest material known to man (where strength is not to be confused with hardness). It also has electrical properties superior to the silicon used to make the chips found in modern electronics. The combination of these properties can make graphene an ideal material for nanoelectromechanical systems, which are scaled-down versions of microelectromechanical systems used for sensing any physical characteristics and any physical phenomena including but not limited to temperature, vibration, and acceleration experienced by papermaking belt 10 during use.
[0045] Due to the continuous shrinking of electrical circuits, particularly those involved in creating and processing radio-frequency signals, they are harder to miniaturize. These ‘off-chip’ components can take up a lot of space and electrical power in comparison to the overall size of ultra-small systems. In addition, most of these radio wave-related components cannot be easily tuned in frequency, requiring multiple copies to ensure the range of frequencies used for wireless communication is covered. Graphene NEMS can address both problems in that they are compact and easily integrated with other types of electronics. Further, their frequency can be tuned over a wide range of frequencies because of the tremendous mechanical strength of graphene.
[0046] The measurement devices 50 may also comprise identification information, such as a code, an ID number, or the like. In addition to identification information, measurement devices 50 may comprise at least one other piece of information, which can include papermaking belt type number, manufacturer information, order information, date, order number or any other information that can be utilized during the installation, use, maintenance, manufacture, or quality control of the papermaking belt 10 or for ordering new papermaking belts 10 . The measurement devices 50 may comprise at least one memory wherein, in addition to the identification information, at least one piece of additional information (such as any physical characteristics of papermaking belt 10 measured during use) may be stored. The information stored in the memory can be changed during the process, during repair or washing of the belt 10 , as well as during storage thereof.
[0047] The data obtained from the measurement devices 50 may be utilized in controlling the papermaking process, choosing an appropriate belt for a papermaking process, clearing failures during the manufacture of products, as well as in choosing papermaking process operating parameters. Such an enhanced data acquisition system may thus significantly improve the efficiency and efficacy of the papermaking process as well as the papermaking belt 10 itself. Collected data can be forwarded from the data acquisition system for managing the production of, the use of, and/or the storage of the belts 10 as well as monitoring any necessary papermaking process conditions during the production of paper products that use papermaking belt 10 .
[0048] The measurement device 50 may comprise a tag responding to radio-frequency electromagnetic radiation. Identification distances and wave transmittivity, for instance, may be influenced by using different radio frequencies. The data acquisition system may further utilize tags responding to different frequencies of different sensors that can be used for measurement devices 50 (e.g., temperature, belt deformation, belt and/or process pressure, and the like). Additionally, the measurement devices 50 may comprise a tag, a transponder containing an antenna for receiving radio-frequency electromagnetic radiation as well as a microchip wherein the identification information is stored. Further, the measurement devices 50 may comprise a so-called Radio Frequency Identification (RFID) tag. The tag can be extremely small thereby making it easier to position within or upon the belt 10 . Such RFID tags are inexpensive, reliable, and highly available.
[0049] Measurement device 50 can be a passive RFID tag which comprises no power source of its own but the extremely low electric current required by its operation is induced by radio-frequency scanning received by the antenna contained within measurement device 50 and transmitted by the receiver 60 . By means of this induced current, the tag is able to transmit a response to an inquiry sent by the reading device. In other words, the reading device searches through (e.g., scans) the environment for a tag, and the tag transmits, for example, a measured physical characteristic of papermaking belt 10 , any ID code, and/or any other relevant and/or necessary information stored in the microchip (response) after the scanning has induced thereto the electric current necessary for the transmission. The RFID tag may be read at a radio frequency without visual communication and it may be read even through obstacles. In addition, exemplary RFID readers can read a plurality of measurement devices 50 , such as RFID tags, simultaneously.
[0050] The measurement devices 50 may comprise one or more portable electronic terminal devices suitable as a reading device 60 . The reading device 60 may be a data acquisition device, portable computer, palmtop computer, mobile telephone or another electronic device provided with the necessary means for remote-reading a tag. The reading device 60 may comprise a control unit included in the monitoring system.
[0051] By way of non-limiting example, measurement devices 50 can comprise thermocouples for measuring the temperature of the papermaking belt 10 . Alternatively, the measurement device 50 could comprise a strain gauge sensor that would be suitable for measuring the bending moment, tension, stress, and/or strain present within papermaking belt 10 . Yet still, measurement device 50 could be provided as a pressure sensor, a pH sensor, or even a wear (i.e., erosion) gauge.
[0052] If measurement device 50 is provided as a thermocouple, a thermocouple suitable for use as a measurement device 50 could be woven into the reinforcing structure 33 . Alternatively, the measurement device 50 could be disposed upon the reinforcing structure 33 and/or affixed to the reinforcing structure 33 by needlework or by way of adhesive. Further, measurement device 50 could be printed onto the reinforcing structure 33 using 3D-printing technology, for example. In any regard, it is preferred that measuring device 50 not have any adverse impact on the overall permeability of the papermaking belt 10 .
[0053] It is also believed that the measurement device 50 can be woven into the portion of the papermaking belt that is overlapped and re-woven to form a seam that makes papermaking belt 10 an endless loop. If it is chosen to apply the measurement device 50 only at this location on the papermaking belt 10 , one of skill in the art will understand that during use of the papermaking belt 10 , the result will be suitable measurements taken in a highly periodic fashion. For example, if a papermaking belt is 200 feet in overall length, and during manufacturing is operated at a linear speed of 2,000 feet/minute, the seam portion of papermaking belt 10 having measurement devices 50 disposed therein/thereon, can provide a measurement at any given point in the manufacturing process every 10 seconds.
[0054] Alternatively, it is believed that measurement device 50 can be provided as a portion of a bi-component filament material utilized to form reinforcing structure 33 . In other words, the measurement device 50 can be arranged as a filament that includes the measurement device 50 (and any associated electronics) as either the inner or outer portion of a coaxially formed bi-component filament or any other type of high performance cable. In this manner, one of skill in the art will recognize that any number of measurement devices 50 can be woven into and incorporated as part of reinforcing structure 33 at any location, or in any number of locations, within the confines of reinforcing structure 33 .
[0055] Yet still, if measurement device 50 is provided as a MEMS or NEMS (discussed supra), it is believed that one of skill in the art could incorporate such a MEMS or NEMS sensor(s) into the resin used to form the framework 32 . In this way a significant number of measurement devices 50 can be incorporated across the papermaking belt 10 in the CD, over its length in the MD, and combinations thereof. Measurement devices 50 can be disposed collinearly, sinusoidally, randomly, or in any fashion across the CD, MD, and combinations thereof. The use of such MEMS and/or NEMS sensors can significantly reduce any effects and/or impact of disposing a measurement device 50 into a papermaking belt 10 by reducing the amount of physical effort necessary to incorporate a measurement device 50 into the reinforcing structure 33 or the framework 32 as well as reduce the impact to the permeability of the papermaking belt 10 due to any portions of the measurement device 10 that may be disposed within a given conduit 36 .
Process for Making a Papermaking Belt
[0056] As indicated above, the papermaking belt 10 can take a variety of forms. While the method of construction of the papermaking belt 10 is immaterial so long as it has the characteristics required to manufacture paper products, certain methods have been discovered to be useful. One exemplary and non-limiting process for making the improved papermaking belt 10 of the present disclosure is described infra.
[0057] A preferred embodiment of an apparatus which can be used to construct a papermaking belt 10 of the present disclosure in the form of an endless belt is shown in schematic outline in FIG. 6 . In order to show an overall view of the entire apparatus for constructing a papermaking belt in accordance with the present disclosure, FIG. 6 was simplified to a certain extent with respect to some of the details of the process. The details of this apparatus, and particularly the manner in which the passageways 37 and the surface texture irregularities 38 are imparted to the backside network 35 a of the second surface 35 of the framework 32 are shown in the figures which follow. It should be noted at this point that the scale of certain elements shown may be somewhat exaggerated in the following drawing figures.
[0058] The overall process for making the improved papermaking belt 10 generally involves coating a reinforcing structure 33 having measurement devices 50 disposed therein or thereupon with a liquid photosensitive polymeric resin 70 when the reinforcing structure 33 is traveling over a forming unit or table 71 (or “casting surface”) 72 . Alternatively, a measurement device 50 provided as a MEMS or NEMS could be dispersed within the resin used to coat the reinforcing structure 33 .
[0059] As shown in FIG. 6 , the resin, or “the coating” 70 (with or without MEMS and/or NEMS) is applied to at least one (and preferably both) sides(s) of the reinforcing structure 33 (with or without a measuring device 50 disposed therein or thereupon) so the coating 70 substantially fills the void areas of the reinforcing structure 33 and forms a first surface 34 ′ and a second surface 35 ′. The coating 70 is distributed so that at least a portion of the second surface 35 ′ of the coating is positioned adjacent the casting surface 72 of the forming unit 71 . The coating 70 is also distributed so that the paper-facing side 51 of the reinforcing structure 33 is positioned between the first and second surfaces 34 ′ and 35 ′ of the coating 70 . In addition, as shown in FIG. 7 , the coating 70 is distributed so portions of the second surface 35 ′ of the coating are positioned between the opaque first portion P 01 of the reinforcing component 40 and the working surface 72 of the forming unit 71 . The portion of the coating which is positioned between the first surface 34 ′ of the coating and the paper-facing side 51 of the reinforcing structure 33 forms a resinous overburden t 0 ′. The thickness of the overburden t 0 ′ can be controlled to a preselected value.
[0060] The liquid photosensitive resin 70 is then exposed to a light having an activating wavelength (light which will cure the photosensitive liquid resin) from a light source 73 through a mask 74 which has opaque regions 74 a and transparent regions 74 b and through the reinforcing structure 33 . The portions of the resin which have been shielded or protected from light by the opaque regions 74 a of the mask 74 and by the first portion P 01 of the reinforcing structure 33 are not cured by the exposure to the light. The remaining portions of the resin (the unshielded portions, and those portions that the second portion P 02 of the reinforcing structure 33 permits the curing of) are cured. The uncured resin is then removed to leave conduits 36 which pass through the cured resin framework 32 .
[0061] For convenience, the stages in the overall process are broken down into a series of steps and examined in greater detail in the discussion which follows. It is to be understood, however, that the steps described below are intended only to provide an exemplary embodiment and to assist the reader in understanding a method of making the papermaking belt of the present disclosure.
[0062] First Step
[0063] The first step of the process of the present disclosure is providing a forming unit 71 with a working surface 72 . The forming unit 71 has working surface which is designated 72 . Preferably, the forming unit 71 is covered by a barrier film 76 which prevents the working surface 72 from being contaminated with resin. The barrier film 76 also facilitates the removal of the partially completed papermaking belt 10 ′ from the forming unit 71 . Generally, the barrier film 76 can be any flexible, smooth, planar material such as polypropylene, polyethylene, or polyester sheeting. Preferably, the barrier film 76 also either absorbs light of the activating wavelength, or is sufficiently transparent to transmit such light to the working surface 72 of the forming unit 71 , and the working surface 72 absorbs the light.
[0064] The barrier film 76 contacts the working surface 72 of forming unit 71 and is temporarily constrained against the working surface 72 . The barrier film 76 travels with the forming unit 71 as the forming unit 71 rotates. The barrier film 76 is eventually separated from the working surface 72 of the forming unit 71 . Preferably, the forming unit 71 is also provided with a means for insuring that barrier film 76 is maintained in close contact with its working surface 72 . Preferably, the barrier film 76 is held against the working surface 72 .
[0065] Second Step
[0066] The second step of the process of the present disclosure is providing a reinforcing structure 33 , for incorporation into the papermaking belt. FIG. 7 shows that the reinforcing structure 33 has a paper-facing side 51 , a machine-facing side 52 opposite the paper-facing side 51 , interstices 39 , and a reinforcing component 40 comprised of a plurality of structural components 40 a . A first portion P 01 of the reinforcing component 40 can have a first opacity 0 1 and a second portion P 02 of the reinforcing component 40 can have a second opacity 0 2 less than the first opacity 0 1 . The first opacity 0 1 is preferably sufficient to substantially prevent curing of the photosensitive resinous material when the photosensitive resinous material is in its uncured state and the first portion is positioned between the photosensitive resinous material and an actinic light source 73 . The second opacity 0 2 is preferably sufficient to permit curing of the photosensitive resinous material. Preferably, the reinforcing structure 33 is a woven, multilayer fabric.
[0067] If a measurement device 50 is provided, it could be woven into the reinforcing structure 33 . Alternatively, the measurement device 50 could be disposed upon the reinforcing structure 33 and/or affixed to the reinforcing structure 33 by needlework or by way of adhesive. Further, measurement device 50 could be printed onto the reinforcing structure 33 using 3D-printing technology, for example.
[0068] It is also believed that the measurement device 50 can be woven into the portion of the papermaking belt that is overlapped and re-woven to form a seam that makes papermaking belt 10 an endless loop. Alternatively, it is believed that measurement device 50 can be provided as a portion of a bi-component filament material utilized to form reinforcing structure 33 . In other words, the measurement device 50 can be arranged as a filament that includes the measurement device 50 (and any associated electronics) as either the inner or outer portion of a coaxially formed bi-component filament or any other type of high performance cable. In this manner, one of skill in the art will recognize that any number of measurement devices 50 can be woven into and incorporated as part of reinforcing structure 33 at any location, or in any number of locations, within the confines of reinforcing structure 33 .
[0069] Since the preferred papermaking belt 10 is in the form of an endless belt, the reinforcing structure 33 should also be an endless belt since the papermaking belt 10 is constructed around the reinforcing structure 33 . As illustrated in FIG. 6 , the reinforcing structure 33 which has been provided is arranged so that it travels in the direction indicated by directional arrow Dl. It is to be understood that in the apparatus used to make the papermaking belt of the present disclosure, there are conventional guide rolls, return rolls, drive means, support rolls and the like which are not shown or identified with specificity in FIG. 6 .
[0070] Third Step
[0071] The third step in the process of the present disclosure is bringing at least a portion of the machine-facing side 52 of the reinforcing structure 33 into contact with the working surface 72 of the forming unit 71 (or more particularly in the case of the embodiment illustrated, traveling the reinforcing structure 33 over the working surface 72 of the forming unit 71 ). At least a portion of the machine-facing side 52 of the reinforcing structure 33 is brought into contact with the barrier film 76 so that the barrier film 76 is interposed between the reinforcing structure 33 and the forming unit 72 .
[0072] Fourth Step
[0073] The fourth step in the process is applying a coating of liquid photosensitive resin 70 to at least one side of the reinforcing structure 33 having the measurement devices 50 incorporated therein or disposed thereupon. Generally, the coating 70 is applied so that the coating 70 substantially fills the void areas 39 a of the reinforcing structure 33 (the void areas are defined below). The coating 70 is also applied so that it forms a first surface 34 ′ and a second surface 35 ′. The coating 70 is distributed so that at least a portion of the second surface 35 ′ of the coating 70 is positioned adjacent the working surface 72 of the forming unit 71 . The coating 70 is distributed so that the paper-facing side 51 of the reinforcing structure 33 is positioned between the first and second surfaces 34 ′ and 35 ′ of the coating 70 . The portion of the coating which is positioned between the first surface 34 ′ of the coating and the paper-facing side 51 of the reinforcing structure 33 forms a resinous overburden t 0 ‘. The coating 70 is also distributed so that portions of the second surface 35 ’ of the coating 70 are positioned between the first portion P 01 of the reinforcing component 40 and the working surface 72 of the forming unit 71 .
[0074] Suitable photosensitive resins can be readily selected from the many available commercially. Resins which can be used are materials, usually polymers, which cure or cross-link under the influence of actinic radiation, usually ultraviolet (UV) light. Such a resin can be provided with measurement devices 50 provided as NEMS contained therein.
[0075] The application of resin 70 by the extrusion header 79 is employed in conjunction with the application of a second coating of liquid photosensitive resin 70 at a second stage by a nozzle 80 located adjacent to the place where the mask 74 is introduced into the system. The nozzle 80 applies the second coating of liquid photosensitive resin 70 to the paper-facing side 51 of the reinforcing structure 33 . It is necessary that liquid photosensitive resin 70 be evenly applied across the width of reinforcing structure 33 and that the requisite quantity of material be worked through interstices 39 to substantially fill the void areas 39 a of the reinforcing structure 33 .
[0076] It is also believed that the measurement device 50 can be placed into a portion of the resin that has been applied to the papermaking belt 10 . In other words, the measurement device 50 can be pushed into the resin forming the papermaking belt so that the resin can envelop the measurement device 50 prior to any curing process. In this way, the measurement device 50 (and any associated electronics) can be incorporated at any location, or in any number of locations, within the confines of papermaking belt 10 .
[0077] Fifth Step
[0078] The fifth step involves control of the thickness of the overburden t 0 ′ of the resin coating 70 to a preselected value. In the preferred embodiment of the belt making apparatus shown in the drawings, this step takes place at approximately the same time, i.e., simultaneously, with the second stage of applying a coating of liquid photosensitive resin to the reinforcing structure 33 . The preselected value of the thickness of the overburden corresponds to the thickness desired for the papermaking belt 10 and follows from the expected use of the papermaking belt 10 .
[0079] Sixth Step
[0080] The sixth step in the process of this disclosure can be considered as either a single step or as two separate steps which comprise: (1) providing a mask 74 having opaque 74 a and transparent regions 74 b in which the opaque regions 74 a together with the transparent regions 74 b define a preselected pattern in the mask; and (2) positioning the mask 74 between the coating of liquid photosensitive resin 70 and an actinic light source 73 so that the mask 74 is in contacting relation with the first surface 34 ′ of the coating of liquid photosensitive resin 70 . The purpose of the mask 74 is to protect or shield certain areas of the liquid photosensitive resin 70 from exposure to light from the actinic light source. It follows that if certain areas are shielded, it follows that any liquid photosensitive resin 70 in those areas that are not shielded will be exposed later to activating light and will be cured.
[0081] The mask 74 can be made from any suitable material which can be provided with opaque regions 74 a and transparent regions 74 b . A material in the nature of a flexible photographic film is suitable for use as a mask 74 . The flexible film can be polyester, polyethylene, or cellulosic or any other suitable material. The opaque regions 74 a should be opaque to light which will cure the photosensitive liquid resin. The opaque regions 74 a can be applied to mask 74 by any convenient means such as by a blue printing (or ozalid processes), or by photographic or gravure processes, flexographic processes, or rotary screen printing processes.
[0082] It should be understood that if one of skill in the art provides the measurement devices 50 as MEMS and/or NEMS, one could incorporate the measurement devices 50 into the treatments and/or solutions used to create the mask 74 . This could allow for the measurement devices 50 to be effectively transferred to the surface of the resulting papermaking belt 10 . In this case it would be preferred that such a measurement device 50 be transparent to the actinic radiation used in the curing process so not to interfere with the resin curing process.
[0083] Seventh Step
[0084] The seventh step of the process of this disclosure comprises curing the unshielded portions of liquid photosensitive resin in those regions left unprotected by the transparent regions 74 b of the mask 74 and curing those portions of the coating 70 that the second portion P 02 of the reinforcing structure 33 permits the curing of, and leaving the shielded portions and those portions of the coating positioned between the first portion P 01 of the reinforcing structure 33 and the working surface 72 of the forming unit 71 uncured by exposing the coating of liquid photosensitive resin 70 to light of an activating wavelength from the light source 73 through the mask 74 . When the barrier film 76 and the reinforcing structure 33 are still adjacent the forming unit 71 , the liquid photosensitive resin 70 is exposed to light of an activating wavelength which is supplied by an exposure lamp 73 .
[0085] The exposure lamp 73 , in general, is selected to provide illumination primarily within the wavelength which causes curing of the liquid photosensitive resin 70 . That wavelength is a characteristic of the liquid photosensitive resin 70 . Any suitable source of illumination, such as mercury arc, pulsed xenon, electrode-less, and fluorescent lamps, can be used. As described above, when the liquid photosensitive resin 70 is exposed to light of the appropriate wavelength, curing is induced in the exposed portions of the resin 70 . Curing is generally manifested by a solidification of the resin in the exposed areas. Conversely, the unexposed regions remain fluid. The intensity of the illumination and its duration depend upon the degree of curing required in the exposed areas.
[0086] In the preferred embodiment of the present disclosure, the angle of incidence of the light is collimated to better cure the photosensitive resin in the desired areas, and to obtain the desired angle of taper in the walls 44 of the finished papermaking belt 10 . Other means of controlling the direction and intensity of the curing radiation, include means which employ refractive devices (i.e., lenses), and reflective devices (i.e., mirrors). The preferred embodiment of the present disclosure employs a subtractive collimator (i.e., an angular distribution filter or a collimator which filters or blocks UV light rays in directions other than those desired). Any suitable device can be used as a subtractive collimator. A dark colored, preferably black, metal device formed in the shape of a series of channels through which light directed in the desired direction may pass is preferred. In the preferred embodiment of the present disclosure, the collimator is of such dimensions that it transmits light so the resin network, when cured, has a projected surface area of about 20-50% on the topside of the papermaking belt 10 and about 50-80% on the backside.
[0087] Eighth Step
[0088] The eighth step in the process in the present disclosure is removing substantially all of the uncured liquid photosensitive resin from the partially-formed composite belt 10 ′ to leave hardened resin framework 32 around at least a portion of the reinforcing structure 33 . In this step, the resin which has been shielded from exposure to light is removed from the partially-formed composite belt 10 ′ to provide the framework 32 with a plurality of conduits 36 in those regions which were shielded from the light rays by the opaque regions 74 a of the mask 74 and passageways 37 that provide surface texture irregularities 38 in the backside network 35 b of the framework 32 .
[0089] As shown in FIG. 25 , at a point in the vicinity of the mask guide roll 82 , the mask 74 and the barrier film 76 are physically separated from the partially-formed composite belt 10 ′. The composite of the reinforcing structure 33 and the partly cured resin 70 travels to the vicinity of the first resin removal shoe 83 a where a vacuum is to remove a substantial quantity of the uncured liquid photosensitive resin from the composite belt 10 ′.
[0090] As the composite belt 10 ′ travels farther, it is brought into the vicinity of resin wash shower 84 and resin wash station drain 85 at which point the composite belt 10 ′ is thoroughly washed with water or other suitable liquid to remove essentially all of the remaining uncured liquid photosensitive resin which is discharged from the system through resin wash station drain 85 .
[0091] The composite belt 10 ′ is then subjected to a second exposure of light of the activating wavelength by post cure UV light source 73 a . This second exposure, however, takes place when the composite belt 10 ′ is submerged in a bath 88 . The process continues until such time as the entire length of reinforcing structure 33 has been treated and converted into the papermaking belt 10 . At the second resin removal shoe 83 b , any residual wash liquid and uncured liquid resin is removed from the composite belt 10 ′ by the application of vacuum.
[0092] It is also believed that the measurement device 50 can be placed into any portion of the cured resin remaining on the papermaking belt 10 . In other words, a recess can be formed within the confines of the papermaking belt 10 and the measurement device 50 disposed therein. By way of non-limiting example only, a slot can be excised into the surface of the papermaking belt 10 and a measurement device 50 placed within the geometry of the slot so that the measurement device 50 (and any associated electronics) remains disposed below the surface of the papermaking belt 10 . Resin can then be applied and cured into the slot so formed thereby covering the measurement devices 50 .
The Papermaking Process
[0093] The papermaking process which utilizes the improved papermaking belt 10 of the present disclosure is described below, although it is contemplated that other processes may also be used to make the paper products described herein. Returning again to FIG. 1 , a simplified, schematic representation of one embodiment of a continuous papermaking machine useful in the practice of the papermaking process of the present disclosure is shown.
[0094] First Step
[0095] The first step in the practice of the papermaking process of the present disclosure is the providing of an aqueous dispersion of papermaking fibers 14 . The aqueous dispersion of papermaking fibers 14 is provided to a head box 13 . The aqueous dispersion of papermaking fibers 14 supplied by the head box 13 is delivered to a forming belt, such as the Fourdrinier wire 15 for carrying out the second step of the papermaking process. The Fourdrinier wire 15 is propelled in the direction indicated by directional arrow A by a conventional drive means which is not shown in FIG. 1 .
[0096] Second Step
[0097] The second step in the papermaking process is forming an embryonic web 18 of papermaking fibers on a foraminous surface from the aqueous dispersion 14 supplied in the first step. After the embryonic web 18 is formed, it travels with Fourdrinier wire 15 and is brought into the proximity of a second papermaking belt, the papermaking belt 10 of the present disclosure.
[0098] Third Step
[0099] The third step in the papermaking process is contacting (or associating) the embryonic web 18 with the paper-contacting side 11 of the papermaking belt 10 of the present disclosure. The purpose of this third step is to bring the embryonic web 18 into contact with the paper-contacting side of the papermaking belt 10 on which the embryonic web 18 , and the individual fibers therein, will be subsequently deflected, rearranged, and further dewatered. The Fourdrinier wire 15 brings the embryonic web 18 into contact with, and transfers the embryonic web 18 to the papermaking belt 10 of the present disclosure in the vicinity of vacuum pickup shoe 24 a.
[0100] As illustrated in FIG. 1 , the papermaking belt 10 of the present disclosure travels in the direction indicated by directional arrow B. The papermaking belt 10 passes around return rolls 19 a and 19 b , impression nip roll 20 , return rolls 19 c , 19 d , 19 e and 19 f , and emulsion distributing roll 21 .
[0101] It can be preferred that receivers 60 be staged around that portion of the papermaking process where the papermaking belt 10 of the present disclosure is used. In particular it could be advantageous to position the receiver(s) at locations that follow a heating process. For example, it may be advantageous to position receivers 60 after pre-dryer 26 . In this manner, the temperature of the papermaking belt 10 having measurement devices 50 disposed therein or thereupon in the form of thermocouples, can provide in situ feed-back of actual, real-time temperatures experienced by the papermaking belt 10 . By way of non-limiting example only, if a papermaking belt 10 , having thermocouples disposed therein, experiences a papermaking process temperature that is higher than required or allowed upon exiting pre-dryer 26 , the temperature of the pre-dryer 26 can be accordingly adjusted in order to reduce energy costs, produce paper products within specification, and preserve papermaking belt 10 life by reducing or even preventing the occurrence of micro-fractures or oxidation of the resin forming the papermaking belt 10 that causes the papermaking belt 10 to become brittle. All of these beneficial end results can result in lower manufacturing costs for paper products.
[0102] Fourth Step
[0103] The fourth step in the papermaking process involves applying a fluid pressure differential of a suitable fluid to the embryonic web 18 with a vacuum source to deflect at least a portion of the papermaking fibers in the embryonic web 18 into the conduits 36 of the papermaking belt 10 and to remove water from the embryonic web 18 through the conduits 36 to form an intermediate web 25 of papermaking fibers. The deflection also serves to rearrange the fibers in the embryonic web 18 into the desired structure.
[0104] Either at the time the fibers are deflected into the conduits 36 or after such deflection occurs, water is removed from the embryonic web 18 through the conduits 36 . Water removal occurs under the action of the fluid pressure differential. It is important, however, that there be essentially no water removal from the embryonic web 18 prior to the deflection of the fibers into the conduits 36 . As an aid in achieving this condition, at least those portions of the conduits 36 surrounded by the paper side network 34 a , are generally isolated from one another. This isolation, or compartmentalization, of conduits 36 is of importance to insure that the force causing the deflection, such as an applied vacuum, is applied relatively suddenly and in a sufficient amount to cause deflection of the fibers. This is to be contrasted with the situation in which the conduits 36 are not isolated. In this latter situation, vacuum will encroach from adjacent conduits 36 which will result in a gradual application of the vacuum and the removal of water without the accompanying deflection of the fibers.
[0105] Fifth Step
[0106] The fifth step is traveling the papermaking belt 10 and the embryonic web 18 over the vacuum source described in the fourth step. The belt 10 carries the embryonic web 18 on its paper-contacting side 11 over the vacuum source. At least a portion of the textured backside 12 of the belt 10 is generally in contact with the surface of the vacuum source as the belt 10 travels over the vacuum source. Following the application of the vacuum pressure and the traveling of the papermaking belt 10 and the embryonic web 18 over the vacuum source, the embryonic web 18 is in a state in which it has been subjected to a fluid pressure differential and deflected but not fully dewatered, thus it is now referred to as intermediate web 25 .
[0107] It could be advantageous to position the receiver(s) 60 at locations that follow such a vacuum process. For example, it may be advantageous to position receivers 60 after the vacuum source described supra. In this manner, the temperature of the papermaking belt 10 having measurement devices 50 disposed therein or thereupon in the form of a strain gauge can provide in situ feed-back of actual, real-time bending moment, stress, strain, erosion, and or combinations thereof experienced by the papermaking belt 10 . By way of non-limiting example only, if a papermaking belt 10 , having a strain gauge disposed therein, experiences a papermaking stress and/or strain that is higher than required or allowed upon exiting the vacuum source, the vacuum pressure applied by the vacuum source can be accordingly adjusted in order to reduce energy costs, produce paper products within specification, and preserve papermaking belt 10 life by reducing or even preventing the occurrence of micro-fractures or oxidation of the resin forming the papermaking belt 10 that causes the papermaking belt 10 to become brittle. All of these beneficial end results can result in lower manufacturing costs for paper products.
[0108] Sixth Step
[0109] The sixth step in the papermaking process is an optional step which comprises drying the intermediate web 25 to form a pre-dried web of papermaking fibers. Any convenient means conventionally known in the papermaking art can be used to dry the intermediate web 25 . For example, flow-through dryers, non-thermal, capillary dewatering devices, and Yankee dryers, alone and in combination, are satisfactory.
[0110] After leaving the vicinity of vacuum box 24 , the intermediate web 25 , which is associated with the papermaking belt 10 , passes around the return roll 19 a and travels in the direction indicated by directional arrow B. The intermediate web 25 then passes through optional pre-dryer 26 . This pre-dryer 26 can be a conventional flow-through dryer (hot air dryer) well known to those skilled in the art.
[0111] Receivers 60 can be staged around that portion of the papermaking process immediately after optional pre-dryer 26 . This can provide for in situ feed-back of actual, real-time temperatures experienced by the papermaking belt 10 during exposure to pre-dryer 26 by measurement devices 50 disposed therein or thereupon. If a papermaking belt 10 having, for example, thermocouples disposed therein, experiences a pre-dryer 26 process temperature that is higher than required or allowed, the temperature of the pre-dryer 26 can be accordingly adjusted in order to reduce or even prevent the occurrence of micro-fractures or oxidation of the resin forming the papermaking belt 10 that causes the papermaking belt 10 to become brittle.
[0112] Seventh Step
[0113] The seventh step in the papermaking process provides for impressing the paper side network 34 a of the papermaking belt 10 of the present disclosure into the pre-dried web by interposing the pre-dried web 27 between the papermaking belt 10 and an impression surface to form an imprinted web of papermaking fibers.
[0114] As illustrated in FIG. 1 when the pre-dried web 27 then passes through the nip formed between the impression nip roll 20 and the Yankee drier drum 28 . As the pre-dried web 27 passes through this nip, the network pattern formed by the paper side network 34 a on the paper-contacting side 11 of the papermaking belt 10 is impressed into pre-dried web 27 to form imprinted web 29 .
[0115] By way of non-limiting example, receivers 60 can preferably be staged around and/or proximate to those portions of the papermaking process where the papermaking belt 10 is subjected to a compressionary process. For example, a receiver could be staged at that portion of the papermaking process that follows contact of the papermaking belt 10 in the nip formed between impression nip roll 20 and the Yankee drier drum 28 . By way of example only, if a papermaking belt 10 , having pressure sensors disposed therein, experiences a higher or lower pressure than what is required, allowed, or the most efficacious to effect transfer of the paper web from one portion of the process to another, the appropriate nip pressure can be accordingly adjusted. Additionally, other critical parameters can be observed and understood in this nip. This can include the nip gap profile uniformity, nip loading profile uniformity, PLI loading uniformity, nip width/belt age profiles, and nip pressure uniformity.
[0116] Additionally, receivers 60 can also preferably be staged around those portions of the papermaking process where the papermaking belt 10 is subjected to other process forces. By way of non-limiting example, it can be seen in real-time if the papermaking belt 10 is experiencing any Poisson contraction effects resulting from thermal or mechanical induced over-stretching of the papermaking belt 10 . Additionally, equipment misalignments can be detected by monitoring the pressures observed by the papermaking belt 10 . Other critical parameters can be observed and understood. This can include the nip gap profile uniformity, nip loading profile uniformity, PLI loading uniformity, nip width/belt age profiles, and nip pressure uniformity. And measurement device 10 could be a chemical sensor to monitor water quality or running pH conditions in the papermaking process. Process anomalies can be detected by providing a measurement device 10 in the form of a plurality of strain gauges disposed within the papermaking belt 10 across the CD (e.g., the center and edges of papermaking belt 10 ) in order to understand, observe, and control the bending moment (i.e., bow deflection and/or skew) experienced by the papermaking belt 10 in process equipment (e.g., a Mt. Hope roll). Additionally, providing measurement device 10 as an accelerometer would be a unique method to understand, observe, and control speed changes between driven rolls of process equipment as well as adjust speeds for drive tuning.
[0117] These examples of the usefulness of the unique papermaking belt 10 can result in a reduction in energy costs, increase papermaking belt 10 life as well as increase the life of the contacted components by reducing wear on the contacting surfaces. It is reasonably believed, without being drawn to any particular theory, that papermaking belt 10 life can be at least doubled by reducing the detrimental effects experienced by the resin. All of these end results can result in lower manufacturing costs for paper products.
[0118] In any regard, the data measured by the measuring device 50 can be incorporated into a database that can be used to establish a papermaking belt 10 profile or a papermaking process profile. The collected data can be compared to an idealized or modeled set-point profile.
[0119] Additionally, the data, and/or the profile can be looped back into the papermaking process. This can allow the adjustment of process temperatures, nip pressures, and the like in situ. Alternatively, the data and/or profile can be used to provide a historical perspective on papermaking belt 10 performance benchmarking over time as well as expected papermaking belt 10 life. Further, the data and/or profile can be used to manage process spikes such as web breakages, e-stops, and power outages that can cause manufacturing equipment to stop but not significantly reduce operating temperatures instantaneously.
[0120] Eighth Step
[0121] The eighth step in the papermaking process is drying the imprinted web 29 . The imprinted web 29 separates from the papermaking belt 10 of the present disclosure after the paper side network 34 a is impressed into the web to from imprinted web 29 . As the imprinted web 29 separates from the papermaking belt 10 of the present disclosure, it is adhered to the surface of Yankee dryer drum 28 where it is dried.
[0122] Ninth Step
[0123] The ninth step in the papermaking process is the foreshortening of the dried web (imprinted web 29 ). This ninth step is an optional, but highly preferred, step. Foreshortening refers to the reduction in length of a dry paper web which occurs when energy is applied to the dry web in such a way that the length of the web is reduced and the fibers in the web are rearranged with an accompanying disruption of fiber-fiber bonds. Foreshortening can be accomplished in any of several well-known ways. The most common, and preferred, method is creping.
[0124] In the creping operation, the dried web 29 is adhered to a surface and then removed from that surface with a doctor blade 30 . The surface to which the web is usually adhered also functions as a drying surface. Typically, this surface is the surface of a Yankee dryer drum 28 . The paper web 31 is then ready for use.
[0125] All publications, patent applications, and issued patents mentioned herein are hereby incorporated in their entirety by reference. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention.
[0126] The dimensions and/or values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension and/or value is intended to mean both the recited dimension and/or value and a functionally equivalent range surrounding that dimension and/or value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm”.
[0127] Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
[0128] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. | A method for adjusting a papermaking process for producing rolls of convolutely wound web material having a machine direction (MD) and a cross-machine direction (CD) coplanar and orthogonal thereto is disclosed. The process improves the operating life of a papermaking belt used therefor. | 3 |
[0001] The present application is a Continuation of U.S. patent application Ser. No. 10/144,806, filed May 15, 2002, which claims the benefit of Korean Patent Application No. P2001-27128 filed in Korea on May 18, 2001, both of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a chemical vapor deposition apparatus, and more particularly to a chemical vapor deposition apparatus for creating a uniform electric field.
[0004] 2. Description of the Related Art
[0005] In general, a liquid crystal display (LCD) controls a light transmittance of liquid crystal cells that are arranged in a matrix array on a liquid crystal display panel. Accordingly, the liquid crystal cells receive data signals, thereby displaying an image (picture). The LCD includes electrodes for supplying an electric field to a liquid crystal layer, a thin film transistor (TFT) for switching the data signals provided to the liquid crystal cells, a lower substrate having signal wiring for supplying the data signals to the liquid crystal cells and signal wiring for supplying control signals of the TFT, an upper substrate having a color filter, a spacer formed between the upper substrate and the lower substrate for providing a predetermined cell gap, and liquid crystal molecules disposed within a space provided between the upper substrate and the lower substrate.
[0006] During fabrication of the liquid crystal display device, a channel portion in an active layer of the TFT and a protective layer protecting the TFT are formed during plasma enhanced chemical vapor deposition (PECVD) processing. During PECVD processing, a gas is injected into a vacuum chamber. Then, at a specific pressure and substrate temperature, the injected gas decomposes into a plasma by use of a radio frequency (RF) voltage, thereby depositing materials onto a surface of the substrate. A quality of the deposited material is dependent upon the deposition conditions, such as the vacuum, the RF voltage, the RF voltage frequency, substrate temperature, reaction gas, and reaction pressure, for example. In addition, the deposited materials includes insulating films, semiconductor films, gate insulating films, protective films, and etch stopper films. The semiconductor films include amorphous silicon (a-Si:H) that form an active layer, and doped amorphous silicon (n+a-Si:H) that form a contact protective layer.
[0007] FIG. 1 is a cross sectional view of a plasma enhanced chemical vapor deposition (PECVD) apparatus according to a related art. In FIG. 1 , the PECVD apparatus includes a gas jet 9 for releasing a gas to be deposited onto a substrate 7 , and a chamber 1 . The chamber 1 includes a susceptor 5 for applying heat via a heating coil to the substrate 7 , an arrow pin 10 for securing the substrate 7 , and a center pin 12 for separating the susceptor 5 from the substrate 7 .
[0008] During processing, the substrate 7 is placed upon the susceptor 5 within the chamber 1 , and the susceptor 5 applies heat to the substrate 7 and functions as a lower electrode for generating a plasma. A temperature of the susceptor 5 averages about 370° C. In addition, the susceptor 5 includes various pins formed to penetrate the susceptor 5 .
[0009] The arrow pin 10 secures the substrate 7 within the chamber 1 , and the center pin 12 rises by a pin plate 16 to prevent any drooping of the substrate 7 . In addition, the center pin and pin plate 16 prevents formation of any scratches between a robot arm 14 and the substrate 7 during loading and unloading of the substrate 7 . The pin plate 16 includes a center pin-supporting portion 18 having the center pin 12 passing through it.
[0010] FIGS. 2A to 2 D show a process for loading a substrate into a chamber according to the related art.
[0011] In FIG. 2A , the substrate 7 is loaded into the chamber 1 by the robot arm 14 , and the substrate 7 , the susceptor 5 , and the center pin 12 are not mutually contacting each other.
[0012] In FIG. 2B , the pin plate 16 rises to mount the center pin-supporting portion 18 in center pin mount portions 20 and 21 equipped on a rear surface of the susceptor 5 , and each of corner pins 22 and 23 and the center pin 12 rise by a power driver (not shown) to lift the substrate 7 .
[0013] In FIG. 2C , the robot arm 14 is separated from the substrate 7 by the power driver (not shown).
[0014] In FIG. 2D , the susceptor 5 rises by a susceptor-lifting portion 24 to make the susceptor 5 lift the substrate 7 and the center pin 12 . Then, the susceptor 5 raises the substrate 7 close to the arrow pin 10 . Accordingly, the substrate 7 is safely placed into a deposition position.
[0015] FIG. 3 is a cross sectional view representing an inside of a chamber according to the related art. In FIG. 3 , the chamber 1 includes the substrate 7 safely placed upon the susceptor 5 , and an upper electrode 30 that faces the substrate 7 with a predetermined gap therebetween. The center pin 12 raises the substrate 7 upon loading, and the susceptor 5 rises. Accordingly, the substrate 7 sustains a predetermined gap from the upper electrode 30 , and the center pin 12 lowers into a center pin hole 19 formed on the susceptor 5 . The center pin 12 is made of ceramic material that has a low coefficient of thermal expansion.
[0016] FIG. 4 is a cross sectional view of a center pin according to the related art as shown in FIG. 3 . In FIG. 4 , an insulating film Al 2 O 3 is formed upon a head portion 3 of the center pin 12 , thereby preventing electrical arcing during plasma processing. Accordingly, the center pin 12 is not ground to the susceptor 5 . However, the heating coil (not shown) formed inside the susceptor 5 is ground with an external ground voltage source GND.
[0017] In FIG. 3 , a radio frequency (RF) voltage source 32 is connected to the upper electrode 30 . Accordingly, an electric field is generated between the upper electrode 30 and the substrate 7 , whereby an insulating film or a semiconductor film is deposited upon a surface of the substrate 7 . When depositing the insulating film or the semiconductor film on the substrate 7 , the electric field emanating from the upper electrode 30 is bowed in a region of the center pin 12 . Accordingly, an electric field density in a region of the center pin 12 is relatively low, thereby a thickness of the deposition film in the region of the center pin 12 will be thinner than surrounding regions.
[0018] FIG. 5 shows a defect resulting from the center pin according to the related art. In FIG. 5 , a thickness of the deposition film in an area A of the substrate 7 , which corresponds to a region of the center pin 12 (in FIG. 3 ), is different from a thickness of the deposition film in other regions.
[0019] FIG. 6 is a spectrum photograph showing the defect on a substrate illustrated in FIG. 5 according to the related art. In FIG. 6 , the thickness of the deposition film in the area A of the substrate 7 , which corresponds to the region of the center pin 12 (in FIG. 3 ), is relatively thinner than the thickness of the deposition film in the other regions.
[0020] FIG. 7 is a graph showing thickness distribution of a deposition film of the substrate 7 (in FIG. 5 ) taken along I-I′ of FIG. 6 . In FIG. 7 , the graphical distribution of deposition thickness of the deposition film on the substrate indicates that a defect is generated in a region corresponding to the center pin 12 (in FIG. 3 ). Accordingly, the defect degrades image quality of the liquid crystal display device.
SUMMARY OF THE INVENTION
[0021] Accordingly, the present invention is directed to a chemical vapor deposition apparatus and method of using the same that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
[0022] An object of the present invention is to provide a chemical vapor deposition apparatus and method of using the same to generate a uniform electric field, thereby forming a deposition film having a uniform thickness.
[0023] Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0024] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a chemical vapor deposition method includes placing a substrate on a susceptor inside a chamber, the susceptor including a center pin passing through the susceptor for lifting the substrate, energizing an electrode to applying a uniform electric field to the substrate, electrically connecting a ground member extending along and attached to an entire axial length of the center pin to a ground voltage source, and forming a film on the substrate by chemical vapor deposition.
[0025] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:
[0027] FIG. 1 is a cross sectional view of a chemical vapor deposition apparatus according to a related art;
[0028] FIGS. 2A to 2 D show a process for loading a substrate into a chamber according to the related art;
[0029] FIG. 3 is a cross sectional view of an inside of a chamber according to the related art;
[0030] FIG. 4 is a cross sectional view of a center pin according to the related art, as shown in FIG. 3 ;
[0031] FIG. 5 shows a defect resulting from the center pin according to the related art;
[0032] FIG. 6 is a spectrum photograph showing the defect on a substrate illustrated in FIG. 5 according to the related art;
[0033] FIG. 7 is a graph showing thickness distribution of a deposition film of the substrate taken along I-I′ of FIG. 6 ;
[0034] FIG. 8 is a cross sectional view showing an exemplary chamber according to the present invention;
[0035] FIG. 9 is a cross sectional view of an exemplary center pin according to the present invention; and
[0036] FIG. 10 is a cross sectional view of another exemplary center pin according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
[0038] FIG. 8 is a cross sectional view showing an exemplary chamber according to the present invention. In FIG. 8 , a chemical vapor deposition apparatus may include a chamber 50 for performing a deposition process on a substrate 37 . The chamber 50 may include a susceptor 45 contacting the substrate 37 , a center pin 42 for lifting the substrate 37 , and an upper electrode 40 facing the substrate 37 and having a predetermined gap therebetween for generating an electric field.
[0039] The substrate 37 may be placed onto the susceptor 45 within the chamber 50 . A heating coil (not shown) may be formed within the susceptor 45 to supply heat to the substrate 37 . The susceptor 45 may also function as a lower electrode for generating a plasma discharge. During the deposition process, a temperature within the susceptor 45 may average about 370° C. The susceptor 45 may include various pins (not shown) that pass through the susceptor 45 for chemical vapor deposition.
[0040] The center pin 42 may be elevated by means of a pin plate 36 to prevent any drooping of the substrate 37 . The pin plate 36 prevents any of the substrate 37 by a robot arm (not shown) during loading and unloading of the substrate 37 . In addition, the pin plate 36 functions to raise the center pin 42 via a power driver (not shown).
[0041] FIG. 9 is a cross sectional view of an exemplary center pin according to the present invention. In FIG. 9 , the center pin 42 may include a head portion 53 , a head supporter 54 , and a grounding terminal 52 . The head portion 53 may include a conductive segment 53 a formed of aluminum (Al), for example, and an insulating segment 53 b such as aluminum oxide (Al 2 O 3 ), for example. The insulating segment 53 b may prevent electrical arcing between the substrate 37 and the susceptor 45 when the electrical field is applied between the susceptor 45 and the upper electrode 40 (in FIG. 8 ).
[0042] The head supporter 54 may be formed of a ceramic material, for example, having a low coefficient of thermal expansion. A ground line 56 may be formed at one side of the head supporter 54 . The ground line 56 may be formed of an electrically conductive metal such as aluminum (Al), for example, inserted into a groove formed at one side of the head supporter 54 and electrically interconnected to the conductive segment 53 a of the head portion 53 .
[0043] The ground terminal 52 may be electrically connected to the conductive segment 53 a of the head portion 53 via the ground line 56 , thereby grounding the center pin 42 to an external ground voltage source GND. The grounding the center pin 42 may be accomplished by electrically connecting a lower part of the center pin 42 to the ground terminal 52 after removing a portion of the ground terminal 52 that has been coated with the insulating segment 43 b . Then, the ground terminal 52 may be connected to a metal line that extends from a lower part of the susceptor 45 , thereby electrically grounding the center pin 42 to the external ground voltage source GND.
[0044] In FIG. 8 , the upper electrode 40 may receive a voltage from a radio frequency voltage source 38 to form a deposition film on the substrate 37 . Accordingly, since the center pin 42 is grounded to the ground voltage source GND via the ground line 56 , a uniform electric field is generated between the susceptor 45 and the upper electrode 40 . This uniform electric field results in a deposition film have a uniform thickness across a surface of the substrate 37 , and prevents formation of any defects within a region of the center pin 42 .
[0045] FIG. 10 is a cross sectional view of another exemplary center pin according to the present invention. In FIG. 10 , the center pin 42 may include a head portion 53 , a head supporter 54 , and a grounding terminal 52 . The head portion 53 may include a conductive segment 53 a formed of aluminum (Al), for example, and an insulating segment 53 b such as aluminum oxide (Al 2 O 3 ). The insulating segment 53 b may prevent electrical arcing between the substrate 37 and the susceptor 45 when the electrical field is applied between the susceptor 45 and the upper electrode 40 (in FIG. 8 ).
[0046] The head supporter 54 may be formed of a ceramic material, for example, having a low coefficient of thermal expansion. A ground line 56 may be formed passing through a center part of the head supporter 54 , and may be formed of an electrically conductive metal, for example, and may electrically interconnect the conductive segment 53 a of the head portion 53 to an external ground voltage source GND via the grounding terminal 52 .
[0047] The ground terminal 52 may be electrically connected to the conductive segment 53 a of the head portion 53 via the ground line 56 , thereby grounding the center pin 42 to an external ground voltage source GND. The grounding the center pin 42 may be accomplished by electrically connecting a lower part of the center pin 42 to the ground terminal 52 after removing a portion of the ground terminal 52 that has been coated with the insulating segment 43 b . Then, the ground terminal 52 may be connected to a metal line that extends from a lower part of the susceptor 45 , thereby electrically grounding the center pin 42 to the external ground voltage source GND.
[0048] In FIG. 8 , the upper electrode 40 may receive a voltage from a radio frequency voltage source 38 to form a deposition film on the substrate 37 . Accordingly, since the center pin 42 is grounded to the ground voltage source GND via the ground line 56 , a uniform electric field is generated between the susceptor 45 and the upper electrode 40 . This uniform electric field results in a deposition film have a uniform thickness across a surface of the substrate 37 , and prevents formation of any defects within a region of the center pin 42 .
[0049] It will be apparent to those skilled in the art that various modifications and variations can be made in the chemical vapor deposition apparatus of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. | A deposition method includes placing a substrate on a susceptor inside a chamber, the susceptor including a center pin passing through the susceptor for lifting the substrate, energizing an electrode to applying a uniform electric field to the substrate, electrically connecting a ground member extending along and attached to an entire axial length of the center pin to a ground voltage source, and forming a film on the substrate by chemical vapor deposition. | 2 |
This application is a continuation of U.S. patent application Ser. No. 11/448,450, filed Jun. 7, 2006, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/687,938, filed Jun. 7, 2005, the entire contents of both of which are incorporated herein by reference.
FIELD OF THE INVENTION
This invention generally relates to thermal imaging systems.
BACKGROUND OF THE INVENTION
The market for thermal imaging systems is large and growing quickly, and is driven by military, security, medical, construction, and automotive markets. Thermal imaging systems typically image thermal wavelengths that scenes at “normal” environmental temperatures, e.g., room or body temperature, radiate. Useful wavelengths for imaging applications include those that the atmosphere readily transmits, and that are not overwhelmed by radiation of the same wavelength from the sun. Thus, thermal imaging systems typically image long wavelength infrared radiation (LWIR), e.g., wavelengths in the range of 7 to 15 microns, that a scene radiates.
Systems that image long wavelength infrared radiation from scenes include narrow-bandgap semiconductor photodetector arrays, which typically require cryogenic cooling, and uncooled microbolometer arrays. These kinds of systems are typically so expensive as to make them inaccessible for the majority of commercial and consumer markets. Additionally, the low yield in producing the array elements for these kinds of systems, and the resulting high cost of manufacturing them, makes it impractical to build high-resolution systems for any but the most cost-insensitive uses.
SUMMARY OF THE INVENTION
A thermal imaging system with optical readout includes thermally tunable pixel elements that generate an image of a scene. The scene radiates infrared radiation, which locally heats the thermally tunable pixel elements with a spatial distribution that corresponds to the scene's thermal characteristics; the local heating changes the reflectivity of the pixel elements. Then, the thermally tunable pixel elements reflect an optical carrier beam with an intensity distribution that corresponds to the local heating that the scene radiation induces, transferring information about the scene to the carrier beam, which the system then images onto a CCD or CMOS detector array. The pixel elements have an improved architecture that includes separate structures for the thermal absorption, structural support, thermal isolation, and carrier beam modulation functions. This allows the structures to be tailored to perform their particular function. The architecture also reduces the relative size of the structure that modulates the carrier beam; because the structure has a relatively large thermal mass, reducing its size reduces the pixel's thermal mass and thus enables its sensitivity or response speed to be improved.
Under one aspect, a thermally tunable pixel element includes a substrate; a thermally tunable filter island; a thermal absorption structure in direct thermal contact with and extending beyond the thermally tunable filter island; and a thermal isolation structure providing a thermally isolating path between the thermal absorption structure and the substrate.
The thermally tunable pixel element may also include one or more of the following features. A plurality of filter islands, wherein the first mentioned filter island is one of the plurality. A thermally isolating trench between each filter island of the plurality of filter islands. A space between the substrate and the thermal absorption structure. The space has a thickness that is about ¼ of a thermal wavelength of interest. A patterned reflective layer that reflects at least the thermal wavelength of interest. A patterned absorbing layer, at least a portion of which absorbs light irradiating the pixel element. The patterned absorbing layer includes an aperture that transmits light irradiating the pixel element. The thermally tunable filter island includes a thermally tunable thin film interference filter. The thermal absorbing structure comprises silicon dioxide, silicon nitride, or a mixture thereof. The thermal absorbing structure comprises a thin metal film.
The thermally tunable pixel element may also include one or more of the following features. The thermal absorption structure supports the filter island from below. The thermal absorption structure supports the filter island from above. The filter island has a smaller area than the thermal absorption structure. The thermal isolation structure includes a support arm for the thermally tunable filter island and thermal absorption structure. The thermal isolation structure comprises a plurality of support arms for the thermally tunable pixel filter island and thermal absorption structure. The thermal isolation structure includes a patterned portion of the thermal absorption structure. The thermal isolation structure includes a thermally isolating post.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a reflection-mode thermal imaging system with thermally tunable pixel elements and optical readout.
FIG. 2A illustrates a plan view of an array of thermally tunable pixel elements.
FIG. 2B illustrates a side view of a single thermally tunable pixel element of FIG. 2A .
FIG. 3 illustrates a side view of a previous design for a thermally tunable pixel element.
FIG. 4A illustrates a plan view of an alternative design for a thermally tunable pixel element.
FIG. 4B illustrates a side view of the thermally tunable pixel element of FIG. 4A .
FIG. 5A illustrates a plan view of a second alternative design for a thermally tunable pixel element.
FIG. 5B illustrates a side view of the thermally tunable pixel element of FIG. 5A .
FIG. 6 illustrates a flow chart of a method of making the thermally tunable pixel elements of FIGS. 4A-4B and 5 A- 5 B.
FIGS. 7A-7G illustrate a side view of intermediate structures formed during fabrication of the thermally tunable pixel element of FIG. 4A-4B .
FIG. 8 illustrates a flow chart of a method of making the thermally tunable pixel elements of FIG. 2A-2B .
FIG. 9 illustrates another configuration for a reflection-mode thermal imaging system with thermally tunable pixel elements and optical readout.
FIG. 10 illustrates a transmission-mode thermal imaging system with thermally tunable pixel elements and optical readout.
DETAILED DESCRIPTION
Thermal imaging systems with optical readouts utilize an array of thermally tunable pixel elements. The optical properties of the pixel elements change according to heating caused by thermal radiation from a scene. A carrier beam irradiates and reflects from the array, and the array's thermally tuned optical properties modify one or more carrier beam characteristics. This transfers thermal information about the scene onto the carrier beam. The system then optically reads out the modified carrier beam, typically using a CMOS or CCD detector array.
FIG. 1 illustrates a reflection-mode thermal imaging system. A long-wavelength (LWIR) lens 101 images a scenes LWIR radiation, shown as a dashed line, onto a “thermal light valve” (TLV) thermal sensor array 102 . The LWIR radiation heats local areas of the TLV differently, according to the thermal characteristics of the scene. This modifies the local reflectivity of the TLV, as described in greater detail below. Separately, a near-infrared (NIR) laser subsystem 103 generates a carrier beam, shown as a dotted line. Beamsplitter 104 directs part (e.g., half) of the carrier beam through collimating lens 105 , and onto the rear surface of TLV 102 . The rear surface of the TLV reflects the carrier beam with an intensity that varies in space according to the local temperature of each portion of the TLV. This transfers thermal information about the scene onto the carrier beam. Lens 105 and beamsplitter 104 re-transmit the reflected and modulated carrier beam. Then, lens 106 images the modulated carrier beam onto CMOS or CCD detector array 107 . Detector array 107 converts the carrier beam into an electrical signal, which hardware and software 108 process to produce a two-dimensional image of the thermal radiation from the scene. Note that FIG. 1 and all subsequent figures are not drawn to scale but are rather intended to be illustrative of the described concepts.
FIG. 2A illustrates a plan view of an array of a TLV architecture for use in the system of FIG. 1 . The TLV includes a patterned array of thermally tunable pixel elements 201 . Each thermally tunable pixel element 201 includes LWIR absorbing structure 215 , three thermally tunable filter islands 210 , thermally isolating post 225 , and thermally isolating trenches 220 . The centers of the pixel elements are about 30 μm apart, and the filter islands are about 17 μm apart, although other appropriate spacings can be used.
LWIR absorbing structure 215 absorbs thermal radiation from the scene. The LWIR radiation intensity varies in space according to the particular thermal characteristics of the scene, and these variations create corresponding local temperature variations in the different pixel elements 201 . This heating changes the optical properties of filter islands 210 , which each include a thermally tuned, thin film interference filter. Specifically, the heating causes a change in the refractive index of filter islands 210 , which slightly shifts their NIR (i.e., carrier beam) bandpass. When the carrier beam reflects from TLV 102 , the thermally induced shift in the bandpass of filter islands 210 , relative to the carrier beam wavelength, modulates the intensity of the reflection. The carrier beam's two-dimensional intensity variations thus directly relate to the scene's thermal radiation.
FIG. 2B illustrates a side view of a single thermally tunable pixel element 201 , relative to incoming LWIR radiation (dashed line) and the carrier beam (dotted line). Thermally isolating post 225 supports LWIR absorbing structure 215 and thermally tunable filter islands 210 , separating them from underlying substrate 235 by a spacing 237 . LWIR absorbing structure 215 absorbs LWIR radiation from the scene, but is transparent to the carrier beam. The underlying substrate 235 further includes mask 230 , which has a reflective layer 231 and an absorptive layer 232 . Reflective layer 231 reflects any initially unabsorbed LWIR radiation back to LWIR absorbing structure 215 , helping the absorbing structure 215 capture additional thermal radiation. Spacing 237 enhances this absorption for LWIR wavelengths that are resonant with the spacing, i.e., that irradiate LWIR absorbing structure 215 in the same place both before and after reflection from reflective layer 231 . Absorptive layer 232 allows the carrier beam to irradiate filter islands 210 , but absorbs the majority of the rest of the carrier beam. This proportionally increases the LWIR-dependent signal in the carrier beam relative to the total beam power that arrives at the detector array. Substrate 235 also includes antireflection (AR) coating 236 , which reduces stray reflections of the carrier beam from the bottom of the substrate. These reflections would otherwise appear as artifacts at the CCD, potentially obscuring the actual image of the scene.
As a point of comparison, FIG. 3 illustrates a side view of an earlier pixel design, which is described in greater detail in U.S. Patent Publication No. 2005/0082480, the entire contents of which are incorporated herein by reference. Pixel element 301 includes LWIR absorbing layer 305 , thermally tunable filter 310 , structural support 315 , spacing 325 , post 340 , and substrate 335 , which perform similar functions to the elements described above. However, in pixel 301 , LWIR absorbing layer, filter 310 , and structural support 315 coextend along the majority of the surface of pixel 301 , essentially forming a single structure.
The performance of a thermally tunable pixel, e.g., pixel 201 of FIG. 2A-2B or pixel 301 of FIG. 3 , is related to a number of parameters, including the efficiency with which it absorbs LWIR radiation; its thermal isolation, which determines the temperature increase that the absorption causes; its thermal mass; and the change in carrier beam signal per change in pixel temperature as measured at the CCD detector array. The time response of the pixel is related to its thermal mass multiplied by its thermal isolation. It is possible to improve the conversion of LWIR absorption by increasing the pixel's thermal isolation of the pixel, but this results in a slower response. On the other hand, the thermally tunable filter can be redesigned to provide a stronger thermal response, but this usually adds thermal mass to the pixel, e.g., by adding more filter layers.
This combination of parameters significantly limits the performance of pixel 301 , because thermally tunable filter 310 , which has a relatively large thermal mass, covers the majority of the pixel surface. Additionally, the filter 310 is designed to modulate the carrier beam, and thus is typically non-ideal for absorbing LWIR radiation. This means adding LWIR absorbing layer 305 , which further increases the thermal mass of the pixel 301 .
In contrast, thermally tunable pixel element 201 of FIGS. 2A and 2B has “separate” structures that each perform separate functions, e.g., LWIR absorption, carrier beam modulation, thermal isolation, and structural support. By “separate” we mean that they function relatively independently of each other, despite the fact that they are joined together. For example, LWIR absorbing structure 215 is independent of, and extends beyond, thermally tunable filter islands 210 . This allows the two structures to be individually fabricated using materials and designs that enhance their respective functionalities.
For example, the LWIR structure's absorption of radiation can be improved by adjusting (a) the composition of the layer, (b) the optical thickness of the layer, (c) the position of the layer relative the surface of the substrate to create appropriate optical interferences, and (d) the optical properties of layers on the substrate, which reflect unabsorbed LWIR radiation back to the LWIR absorbing layer. An example of such a structure includes a layer of silicon oxide and/or silicon nitride, positioned over the substrate by ¼ of the wavelength of interest. Because the LWIR absorption functionality is separate, for example, from the thermal isolation functionality, the LWIR structure's parameters can be changed without necessarily changing the thermal characteristics of the pixel. Or, if changing an LWIR parameter does negatively affect the pixel's thermal characteristic, the thermally isolating structure can be changed to compensate for that without itself detrimentally affecting the LWIR absorption. In other words, the architecture limits the coupling between the performance of different structures with different functions. In pixel 301 of FIG. 3 , the functionalities of the different layers are strongly coupled to each other much more strongly.
Separating functional structures provides an additional benefit in that it is possible to create a regular optical pattern of filter islands that is not constrained by the mechanics or thermal structures of the pixel. For example, it is straightforward to create a regular triangular or square matrix of filter islands (and corresponding apertures). This helps to ease optical constraints on the system as a whole, as well as requirements for subsequent signal processing. Limiting the filter islands to smaller areas also provides space to incorporate new features into the pixel, such as thermally isolating trenches.
The design also makes it possible to use multiple filter patches semi-independently, resulting in better pixel resolution. For example, thermally isolating post 225 , which has a low thermal diffusion constant, and space 237 thermally separate pixel element 201 from adjacent pixel elements, as well as from the underlying substrate 235 . These features help to contain heat within LWIR absorbing structure 215 and filter islands 210 , thus increasing carrier beam modulation and improving image quality. This thermal isolation helps to prevent thermal “cross-talk” between different regions of the TLV, i.e., different pixels, so that heat that the scene radiation generates on one pixel does not readily transfer to another pixel via thermal conduction and smear the image. Thermally isolating trenches 220 , shown in FIG. 2A also thermally isolate filter islands 210 from each other, which further reduces smearing of the image and thus improves resolution.
Additionally, the filter islands 210 of FIG. 2B are relatively small, as compared with the filter 310 of FIG. 3 . Because these elements are thick relative to the rest of the pixel, and thus have a large relative thermal mass, reducing their size reduces the total thermal mass of the pixel. Reducing the pixel's thermal mass, i.e., reducing the amount of material that the thermal radiation heats, translates directly into a higher pixel response speed. For example, assume that a filter layer has ten times the unit mass of an LWIR absorbing layer. Thus, reducing the size of the filter areas to 20% of the entire pixel area (as compared to 100% of the pixel area as for pixel 301 ), results in a 3.7 times smaller thermal mass. This translates directly into a faster thermal response speed, which by adjusting the thermal isolation of the pixel translates to a 3.7 times higher pixel sensitivity.
FIG. 4A illustrates a plan view of an alternate design for a thermally tunable pixel element 401 . Pixel element 401 includes LWIR absorbing structure 415 , three thermally tunable filter islands 410 , post 425 , cavity 420 , and thermally isolating support arm 421 . Support arm 421 is long and thin, and therefore transports heat relatively poorly. This thermally isolates the upper surface of pixel element 401 , e.g., LWIR absorbing structure 415 and filter islands 410 , from post 425 and from the underlying substrate (not shown). In this design, post 425 need not be thermally isolating, because support arm 421 provides thermal isolation. The length, width, and pattern of support arm 421 are selected to provide an appropriate balance of thermal isolation and structural support to pixel element 401 .
FIG. 4B illustrates a side view of the pixel element 401 of FIG. 4A , taken along line 4 - 4 . Thermally isolating support arm 421 , connected to post 425 , supports LWIR absorbing structure 415 and filter islands 410 . In this design, LWIR absorbing structure 415 overlays filter islands 410 , holding them from above and separating them from underlying substrate 435 by spacing 437 . The underlying substrate 435 also includes antireflective coating 436 and mask 430 , which includes reflecting layer 431 and absorbing layer 432 , which have the same functions those described regarding FIG. 2B .
FIG. 5A illustrates a plan view of a second alternate design for a thermally tunable pixel element 501 . Pixel element 501 includes LWIR absorbing structure 515 , three thermally tunable filter islands 510 , and post 525 . This design, however, includes three cavities 520 and three thermally isolating support arms 521 . As for pixel element 401 of FIG. 4A , support arms 521 are long and thin, transporting heat relatively poorly and thus thermally isolating LWIR absorbing structure 515 and filter islands 510 from post 525 and from the underlying substrate (not shown). Here the three support arms 521 extend symmetrically from post 525 , which enhances the balance and structural stability of the pixel relative to the single asymmetric support arm illustrated in FIG. 4A .
FIG. 5B illustrates a side view of the pixel element 501 of FIG. 5A , taken along line 5 - 5 . Thermally isolating support arms 521 , connected to post 525 , support LWIR absorbing structure 515 and filter islands 510 . Pixel 501 also includes substrate 535 , antireflective coating 536 , spacing 537 , and mask 530 , having reflecting layer 531 and absorbing layer 532 , each of which have substantially the same function as those described above.
FIG. 6 illustrates a flow chart of a method 600 of making the thermally tunable pixel elements of FIGS. 4A-4B and FIGS. 5A-5B . The intermediate structures formed, and materials used, are described in greater detail below. The first step of the method provides a substrate and coats one side of it with an antireflective (AR) coating ( 601 ). The next step deposits absorbing and reflective layers on the other side of the substrate from the AR coating and patterns them ( 602 ). This form an aperture that will transmit the carrier beam to the filter islands in the finished structure. The next step deposits, planarizes, and patterns a sacrificial layer ( 603 ) over the absorbing and reflective layers. The sacrificial layer defines the space between the substrate and the upper pixel structure, e.g., the filter islands and LWIR structure, and the pattern in the sacrificial layer provides a hole in which the post will be fabricated. The next step deposits and patterns the filter layer ( 604 ) over the sacrificial layer. This forms the post and the filter islands. The next step deposits and patterns LWIR absorbing layer ( 605 ) over the patterned filter layer, separating the pixel from adjacent pixels in the array and forming thermally-isolating supporting arm(s). The last step removes the sacrificial layer ( 606 ) to form the finished pixel. The different steps in the method can be performed using techniques known in the fields of photolithography and thin film deposition, and are therefore not discussed here in detail.
FIGS. 7A-7G illustrate intermediate structures formed during the different steps of the method of FIG. 6 . As illustrated in FIG. 7A , the first step ( 601 ) provides a substrate 735 and coats one side of it with an AR coating 736 . Here, substrate 735 is glass, which readily transmits the carrier beam and is relatively inexpensive, although other materials that transmit the carrier beam can be used. AR coating 736 is optimized to minimize the carrier beam's reflection at the substrate-air interface, on the bottom of the substrate. Without the AR coating, a non-negligible percentage of the carrier beam would reflect from the interface upon its arrival at the interface, as well as upon its return after reflecting from the filter island. These stray reflections would appear as bright artifacts in the image of the scene.
FIG. 7B illustrates absorbing layer 732 and reflective layer 731 , which the next step ( 602 ) sequentially deposits and patterns on the other side of the substrate from the AR coating. Absorbing layer 732 has a composition and thickness selected to absorb the carrier beam, e.g., NIR radiation, to further reduce the amount of light reaching the CCD that does not contain information about the scene. Reflective layer 731 has a composition and thickness selected to reflect thermal radiation from the scene, so that radiation that the LWIR absorbing structure does not initially absorb can be absorbed on a second pass through the LWIR absorbing structure. The pattern in absorbing layer 732 and reflective layer 731 includes aperture 740 , which in the finished structure will selectively transmit the carrier beam only where it will interact with the filter islands and thus receive information about the scene.
FIG. 7C illustrates the intermediate structure that step ( 603 ) forms by depositing, planarizing, and patterning sacrificial layer 745 . When step ( 603 ) deposits sacrificial layer 745 , the layer conforms to the underlying structure, e.g., fills in aperture 740 in the underlying absorbing and reflective layers. This creates a corresponding depression in the upper surface of sacrificial layer 745 ; planarizing the layer eliminates this depression, so that any structures deposited on top of layer 745 will see a planar surface. As mentioned above, sacrificial layer 745 defines the space between the substrate and the upper pixel structure, e.g., the filter islands and LWIR absorbing structure; in other words, the space will have the same thickness as sacrificial layer 745 has after planarization. A thickness of ¼ the thermal wavelength of interest helps the LWIR absorbing structure absorb that wavelength in the finished pixel. The pattern in sacrificial layer 745 provides hole 746 in which the post will be deposited. Later, after other steps fabricate the filter islands, LWIR absorbing structure, and post, a last step will remove sacrificial layer 745 . In essence, the sacrificial layer's role is to allow the definition of other structures, even though it is not a part of the finished structure. Polyimide is an example of a suitable material for use in sacrificial layer 745 , which has a higher etch rate than that of the other materials in the structure, allowing it to be later removed without damaging the rest of the pixel.
FIGS. 7D and 7E show different intermediate structures that step ( 604 ) creates. First, as FIG. 7D illustrates, step ( 604 ) deposits the filter layer 711 over the patterned and planarized sacrificial layer 745 . The filter layer incorporates semiconductor materials with a refractive index that depends strongly on temperature to create a solid-state, tunable thin film optical filter. See, for example, U.S. Patent Publications No. 2002/0105652 and 2003/0087121, the entire contents of which are incorporated herein by reference. Here, filter layer 711 includes first and second reflecting structures with a spacer between them. The first and second reflecting structures each include 4 layers of amorphous silicon, which has a relatively high refractive index, alternating with 4 layers of silicon nitride, which has a relatively low refractive index. Each layer in the reflecting structure has a thickness corresponding to ¼ of the wavelength of the carrier beam light in that layer, e.g., ¼ of 850 nm, divided by the refractive index of the layer. So, the amorphous silicon layers are each (212.5 nm/3.6), or about 59 nm thick, and the silicon nitride layers are each (212.5 nm/1.8), or about 108 nm thick. The spacer between the first and second reflecting structures is amorphous silicon with a thickness corresponding to the wavelength of the carrier beam light in that layer, e.g., 850 nm divided by the refractive index of amorphous silicon, or about 161 nm. This yields a total filter layer 711 thickness of about 1500 nm. As FIG. 7D illustrates, filter layer 711 conforms to the pattern of sacrificial layer 745 , filling in post hole 746 .
FIG. 7E illustrates the next part of step ( 604 ), which is patterning the filter layer 711 to form the post 725 and filter islands 710 . Although the filter layer has optical properties tailored to provide thermally tunable optical (or thermo-optic) modulation of the carrier beam, it is also mechanically robust. This makes it a good option for use as the post material, which, as discussed above, does not need to be thermally isolating in this design because other structures provide thermal isolation in the pixel. Although it is not illustrated, the filter material can be patterned so that it extends beyond the edge of the post hole and over a portion of the sacrificial layer; this extra material can add additional structural stability to the finished structure. Forming the post 725 and filter islands 710 concurrently also saves time and energy over fabricating them separately, out of separate materials. As FIG. 7E illustrates, step ( 604 ) patterns filter islands 710 directly above the aperture 740 in the absorbing layers 732 and reflecting layers 731 .
As FIG. 7F illustrates, step ( 605 ) first deposits LWIR absorbing layer 715 over the filter islands 710 , post 725 , and sacrificial layer 745 . LWIR absorbing layer conforms to the underlying structures. The material used in LWIR absorbing layer 715 , and the thickness thereof, absorbs thermal radiation relatively well, has a relatively low thermal conductivity, and also has a sufficient mechanical strength that the thermally isolating arm of the final structure adequately supports the filter islands. The illustrated LWIR absorbing layer is a 200 nm layer of silicon nitride, although silicon dioxide, as well as mixtures of silicon dioxide and silicon nitride, can be used. These materials typically have bond vibrations at frequencies that resonate with LWIR radiation, allowing them to absorb light. Alternately, a very thin metal layer, such as titanium or chromium, can also be used as an LWIR absorber even though it absorbs LWIR by a different mechanism. In general, a material with a resistance of about 377 ohms/square (i.e., the resistance of free space) will absorb LWIR radiation particularly well, although the other features of the material must be taken into account. For example, thin metal layers tend to inherently have high stress, which could cause warping in the pixel, and in some cases can also have an undesirably high thermal conductance.
Then, as FIG. 7G illustrates, step ( 605 ) patterns, e.g., lithographically defines a pattern in LWIR absorbing layer to separate the pixel from adjacent pixels in the array, to form cavities 720 , and to form thermally isolating support arm 721 . Note that in this step, because the patterns of cavities 720 and thermally isolating support arm 721 are lithographically defined, selecting a different pattern allows a different thermally isolating structure to be fabricated. In other words, only a minor modification to the step allows substantial revision to the structure's thermal characteristics.
Step ( 606 ) then removes the sacrificial layer 745 , e.g., by etching, to form the finished pixel illustrated in FIGS. 4A-4B . Note that cavities 720 provide an additional pathway for an etchant to remove the sacrificial layer, making it faster to remove the layer and thus reducing potential damage to other structures in the pixel. In contrast, in earlier designs such as pixel 301 of FIG. 3 , the etchant would only be able to access the sacrificial layer by grooves defining the outer edges of the pixel.
The pattern illustrated in FIG. 7G can be varied to form different sizes and shapes of cavities and thermally isolating support arm(s), to provide the desired balance of thermal isolation and structural integrity. For example, the pixel of FIGS. 5A-5B can be fabricated using the steps described above regarding FIGS. 7A-7G , but simply using a different pattern that provides a more symmetrical support to the filter islands.
FIG. 8 illustrates a flow chart of a method 800 of making the thermally tunable pixel element of FIG. 2A-2B , which is similar to that of FIGS. 4A-4B and 5 A- 5 B but instead includes the LWIR absorbing structure below the filter islands, and includes a thermally isolating post. Many of the steps are similar to those described above. The first step of the method provides a substrate and coats one side of it with an antireflective (AR) coating ( 801 ). The next step deposits absorbing and reflective layers on the other side of the substrate from the AR coating and patterns them ( 802 ). This forms an aperture that will transmit the carrier beam to the filter islands in the finished structure. The next step deposits, planarizes, and patterns a sacrificial layer ( 803 ) over the absorbing and reflective layers. The sacrificial layer forms the space between the substrate and the upper pixel structure, e.g., the filter islands and LWIR structure, and the pattern in the sacrificial layer provides an area for the post. The next step deposits and patterns the thermally isolating post ( 804 ). Here, because the post provides thermal isolation to the pixel, a material with low thermal conductivity is used, such as SiO 2 . The next step deposits and patterns LWIR absorbing structure ( 805 ) over the sacrificial layer, separating the pixel from adjacent pixels in the array. The next step deposits and patterns the filter layer ( 806 ) over the LWIR absorbing layer, forming the filter islands. The last step removes the sacrificial layer ( 807 ) to form the finished pixel. The intermediate structures formed in this fabrication method are similar to those described above, and are therefore not described in greater detail.
The reflection-mode system illustrated in FIG. 1 can be modified to provide a similar functionality, but using fewer optics which therefore provides fewer surfaces to generate stray reflections. For example, FIG. 9 illustrates a different kind of reflection-mode system. As for FIG. 1 , an LWIR lens 901 images LWIR radiation from a scene onto a TLV sensor array 902 . An NIR laser subsystem 903 generates a carrier beam, which is aligned to directly irradiate TLV 902 through lens 905 , so that a beamsplitter is not necessary. The carrier beam reflects from TLV 902 , and transmits through lens 905 . Then, lens 906 images the beam onto CCD sensor array 907 . CCD 907 converts the carrier beam to an electrical signal, which hardware and software 908 process to produce an image corresponding to the thermal radiation from the scene.
FIG. 10 illustrates a transmission-mode system. LWIR lens 1001 images LWIR radiation from a scene onto TLV sensor array 1002 , which it heats according to the thermal characteristics of the scene. NIR laser subsystem 1003 generates a carrier beam, which beamsplitter directs to be collinear with the LWIR radiation. The carrier beam transmits through TLV 1002 with a transmission that varies in space according to the local temperature at the TLV. Lens 1005 and lens 1006 image the carrier beam onto CCD detector array 1007 , which converts the carrier beam into an electrical signal that hardware and software 1008 process to produce an image of the scene's thermal characteristics.
In this system, the pixels used in TLV sensor array 1002 are similar in many ways to the pixels described above, having separate structures for thermal absorption, structural support, thermal isolation, and carrier beam modulation. In general, the filter islands modulate the carrier beam similarly upon its reflection or its transmission through the island, so that component would not need to be significantly changed.
Note that in the described systems, not all of the light on the CCD carries information about the scene. For example, non-idealities in the antireflection coating on the bottom of the pixel's substrate can generate stray carrier beam reflections that the CCD records but which do not carry information about the scene. Also, for example, the pixels change the intensity of the carrier beam only by about 1 part in 1000, so most of the light in the carrier beam is unmodulated. This unmodulated light forms a large DC background that the system images onto the CCD detector array along with the thermal signal, which can overwhelm the thermal signal as well as generate noise in the CCD. To further improve the signal at the CCD, optical image processing can be used to reduce or eliminate the DC background. For example, lens 105 of FIG. 1 performs a Fourier transform on the carrier beam in a Fourier plane between lens 105 and lens 106 . In this Fourier plane, the DC and low-frequency background components are spatially separated from the higher frequency signal components, and can be removed with a spatial filter, as described in greater detail in U.S. Provisional Patent Application Nos. 60/690,593, filed Jun. 15, 2005, and 60/775,463, filed Feb. 21, 2006, the entire contents of which are incorporated herein by reference. For the described pixel architectures, the somewhat complicated structure of 3 filter islands on a hexagonal pixel generates a complicated diffraction pattern in the Fourier plane, the 0 th order of which contains the DC background. An appropriate corresponding spatial filter blocks the 0 th diffraction order and allows the other orders to be imaged onto the CCD. Alternately, one or more of the other diffraction orders, e.g., the ±1 orders, can be selected and imaged onto the CCD.
Although the pixel architectures described above have three filter islands per pixel, in general other numbers of filter islands can be used, so long as they sufficiently modulate the carrier beam so the CCD detector array records a usable image of the scene. For example, one, two, four, or more filter islands per pixel can be used. The design of the other structures in the pixel, e.g., the thermally isolating structure(s), can be redesigned accordingly.
Other embodiments are within the following claims. | A thermal imaging device including: a substrate; and an array of thermally tunable pixel elements for generating a thermal image, each thermally tunable pixel element including: a plurality of thermally tunable filter islands, each of which has a thermally tunable optical filter, wherein each of the plurality of tunable filter islands within that pixel element is thermally isolated from the other tunable filter islands within that tunable pixel element; an absorption structure for absorbing incident optical thermal energy; and a mechanical structure supporting the plurality of tunable filter islands and the absorption structure on the substrate. | 6 |
The present application is a Continuation Application of U.S. patent application Ser. No. 13/067,945, filed on Jul. 8, 2011, which is a Continuation Application of U.S. patent application Ser. No. 12/453,736, filed on May 20, 2009, now U.S. Pat. No. 8,004,062, which are based on and claim priority from Japanese patent application No. 2008-148164, filed on Jun. 5, 2008, the entire contents of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device capable of transmitting an electrical signal between two circuits having input electrical signals differing in potential from each other.
2. Description of the Related Art
In a case where an electrical signal is transmitted between two circuits having input electrical signals differing in potential from each other, a photocoupler is ordinarily used. The photocoupler has a light emitting element such as a light emitting diode and a light receiving element such as a phototransistor. An electrical signal input to the photocoupler is converted into light by the light emitting element and the electrical signal is restored from this light by the light receiving element, thus transmitting the electrical signal.
Since the photocoupler has the light emitting element and the light receiving element, it is difficult to reduce the size of the photocoupler. Also, the photocoupler is incapable of following an electrical signal if the frequency of the electrical signal is high. As a technique to solve these problems, a technique of transmitting an electrical signal by using inductive coupling between two inductors, for example, as described in National Publication of International Patent Application No. 2001-513276 has been developed.
Japanese Patent Laid-Open No. 10-163422 discloses a technique of forming an inductance by using a plurality of wiring layers stacked on a semiconductor substrate with interlayer insulating films interposed therebetween. In this technique, first circular-arc wiring patterns forming a winding on the input side and second-circular arc wiring patterns forming a winding on the output side are alternately stacked. In each wiring layer, one of the circular-arc wiring patterns is formed.
The present inventor has recognized as follows. With respect to reducing the size of a device which transmits an electrical signal between two circuits having input electrical signals differing in potential from each other, application of a semiconductor device manufacturing technique to forming inductors in two wiring layers so that the inductors face each other through an interlayer insulating film is conceivable. In such a case, the insulation withstand voltage between the two inductors is insufficient with respect to the potential difference between the two inductors due to the interlayer insulating film having a small thickness. There is, therefore, a demand for a technique to improve the insulating withstand voltage between the two inductors.
SUMMARY
The present invention provides a semiconductor device including a substrate, a multilayer wiring layer formed on the substrate and having an insulating layer and a wiring layer alternately stacked in this order t or more times (t≧3), a first inductor provided in the nth wiring layer in the multilayer wiring layer, and a second inductor provided in the mth wiring layer in the multilayer wiring layer (t≧m≧n+2) and positioned above the first inductor, wherein no inductor is provided in any of the wiring layers positioned between the nth wiring layer and the mth wiring layer to be positioned above the first inductor.
In this semiconductor device, the at least two insulating layers are positioned between the first inductor and the second inductor, and no inductor is provided in any of these insulating layers to be positioned above the first inductor. As a result, the insulation withstand voltage between the first inductor and the second inductor is increased.
According to the present invention, the insulation withstand voltage between the first inductor and the second inductor can be increased.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, advantages and features of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a sectional view of a semiconductor device according to a first embodiment of the present invention;
FIG. 2 is a sectional view of a semiconductor device according to a second embodiment of the present invention;
FIG. 3 is a sectional view of a semiconductor device according to a third embodiment of the present invention;
FIG. 4 is a sectional view showing a modified example of the third embodiment;
FIG. 5 is a sectional view of a semiconductor device according to a fourth embodiment of the present invention;
FIG. 6 is a sectional view of a semiconductor device according to a fifth embodiment of the present invention;
FIG. 7 is a sectional view of a semiconductor device according to a sixth embodiment of the present invention;
FIG. 8 is a sectional view of a semiconductor device according to a seventh embodiment of the present invention; and
FIG. 9 is a sectional view of a semiconductor device according to an eighth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will be described with reference to the accompanying drawings. Similar components are indicated by the same reference numerals and redundancy of descriptions of them is avoided.
FIG. 1 is a sectional view of a semiconductor device in the first embodiment. This semiconductor device has a substrate 10 , a multilayer wiring layer 400 , a first inductor 310 and a second inductor 320 . The multilayer wiring layer 400 , the first inductor 310 and the second inductor 320 are formed on the substrate 10 . The multilayer wiring layer 400 is formed by alternately stacking an insulating layer and a wiring layer in this order t or more times (t≧3). The first inductor 310 is provided in the nth wiring layer in the multilayer wiring layer 400 . The second inductor 320 is provided in the mth wiring layer in the multilayer wiring layer 400 (t≧m≧n+2) and positioned above the first inductor 310 . No inductor is provided in any of the wiring layers positioned between the nth wiring layer and the mth wiring layer to be positioned above the first inductor 310 . The first inductor 310 and the second inductor 320 constitute a signal transmitting device 300 which transmits an electrical signal in either of two directions. The electrical signal is, for example, a digital signal. The electrical signal may alternatively be an analog signal.
In the present embodiment, each of the first inductor 310 and the second inductor 320 is a spiral wiring pattern formed in one wiring layer. Each insulating layer may have a structure in which a plurality of interlayer insulating films are stacked or may be one interlayer insulating film. In the present embodiment, each insulating layer has a structure in which two interlayer insulating films are stacked.
In the present embodiment, the semiconductor device has a structure in which wirings 510 , 520 , 530 , and 540 in four layers are stacked in this order. The wirings 510 , 520 , 530 , and 540 are Cu wirings formed by a damascene method and respectively embedded in channels formed in the wiring layers 412 , 422 , 432 , and 442 . Pads (not shown) are formed in the wiring 540 in the uppermost layer. At least one of the wirings 510 , 520 , 530 , and 540 may be Al alloy wiring.
An interlayer insulating film 410 for forming contact plugs is provided between the substrate 10 and the wiring 510 in the lowermost layer. Insulating layers 420 , 430 , and 440 for forming vias are respectively formed between the wirings 510 and 520 , between the wirings 520 and 530 and between the wirings 530 and 540 . On the substrate 10 , the insulating layer 410 , the wiring layer 412 , the insulating layer 420 , the wiring layer 422 , the insulating layer 430 , the wiring layer 432 , the insulating layer 440 and the wiring layer 442 are stacked in this order.
Each of the insulating films constituting the insulating layers and the wiring layers may be an SiO 2 film or a low-dielectric-constant film. The low-dielectric-constant film may be an insulating film having a dielectric constant of, for example, 3.3 or less, preferably 2.9 or less. As the material of the low-dielectric-constant film, polyhydrogen siloxane, such as hydrogen silsesquioxane (HSQ), methyl silsesquioxane (MSQ) or methylated hydrogen silsesquioxane (MHSQ), an organic material containing an aromatic compound, such as polyallyl ether (PAE), divinyl-siloxane-bis-benzocyclobutene (BCB) or Silk™, SOG, FOX™ (flowable oxide), Cytop™, benzocyclobutene (BCB) or the like may be used as well as SiOC. Also, as the low-dielectric-constant film, a porous film of any of these materials may be used.
The first inductor 310 is positioned in the lowermost wiring layer 412 , while the second inductor 320 is positioned in the uppermost wiring layer 442 . The two wiring layers 422 and 432 and the three insulating layers 420 , 430 , and 440 are positioned between the first inductor 310 and the second inductor 320 .
The substrate 10 is a first conduction type (e.g., p-type) of semiconductor substrate. The semiconductor device further has a first circuit 100 and a second circuit 200 . The first circuit 100 is connected to one of the first inductor 310 and the second inductor 320 constituting the signal transmitting device 300 . The second circuit 200 is connected to the other of the first inductor 310 and the second inductor 320 . These connections are made by means of the multilayer wiring layer 400 on the substrate 10 . The signal transmitting device 300 is positioned, for example, between the first circuit 100 and the second circuit 200 . However, the arrangement is not limited to this. For example, the signal transmitting device 300 may be included in the first circuit 100 or in the second circuit 200 . The first circuit 100 and the second circuit 200 have input electrical signals differing in potential from each other. With respect to the arrangement shown in FIG. 1 , “input electrical signals differ in potential from each other” means that the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other.
The first circuit 100 has first transistors, including a first-conduction-type transistor and a second-conduction-type transistor. A first first-conduction-type transistor 121 is formed in a second-conduction-type well 120 and has two first-conduction-type impurity regions 124 forming a source and a drain and a gate electrode 126 . A first second-conduction-type transistor 141 is formed in a first-conduction-type well 140 and has two second-conduction-type impurity regions 144 forming a source and a drain and a gate electrode 146 . Gate insulating films are respectively positioned below the gate electrodes 126 and 146 . These two gate insulating films are substantially equal in thickness to each other.
A second-conduction-type impurity region 122 is formed in the well 120 , while a first-conduction-type impurity region 142 is formed in the well 140 . A piece of wiring through which a reference potential (ground potential) is applied to the first first-conduction-type transistor 121 is connected to the impurity region 122 , while a piece of wiring through which a reference potential is applied to the first second-conduction-type transistor 141 is connected to the impurity region 142 .
The second circuit 200 has second transistors, also including a first-conduction-type transistor and a second-conduction-type transistor. A second first-conduction-type transistor 221 is formed in a second-conduction-type well 220 and has two first-conduction-type impurity regions 224 forming a source and a drain and a gate electrode 226 . A second second-conduction-type transistor 241 is formed in a first-conduction-type well 240 and has two second-conduction-type impurity regions 244 forming a source and a drain and a gate electrode 246 . Gate insulating films are respectively positioned below the gate electrodes 226 and 246 . In the example shown in the figure, these two gate insulating films are thicker than the gate insulating films of the first transistors provided in the first circuit. However, the gate insulating films of the first transistors and the second transistors may equal in thickness to each other.
A second-conduction-type impurity region 222 is formed in the well 220 , while a first-conduction-type impurity region 242 is formed in the well 240 . A piece of wiring through which a reference potential (ground potential) is applied to the second first-conduction-type transistor 221 is connected to the impurity region 222 , while a piece of wiring through which a reference potential is applied to the second second-conduction-type transistor 241 is connected to the impurity region 242 .
A method of manufacturing the semiconductor device according to the present embodiment will next be described. First, the first transistors are formed in a first region in the substrate 10 (a region where the first circuit 100 is formed as shown in FIG. 1 ), and the second transistors are formed in a second region in the substrate 10 (a region where the second circuit 200 is formed as shown in FIG. 1 ). Next, the multilayer wiring layer 400 is formed on the first transistor and the second transistor. When the multilayer wiring layer 400 is formed, the first inductor 310 and the second inductor 320 are formed above a third region in the substrate 10 (a region above which the signal transmitting device 300 is formed as shown in FIG. 1 ). In the example shown in FIG. 1 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires (not shown). With respect to the arrangement shown in FIG. 1 , “input electrical signals differ in potential from each other” means that the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other.
The operation and advantages of the present embodiment will be described. When electrical energy or an electrical signal is transmitted through two inductors, the transmission efficiency is increased if the two inductors are brought closer to each other. In ordinary cases, therefore, the transmitting device is designed so that the two inductors are brought as close as possible to each other. In a case where the placement of the first inductor 310 and the second inductor 320 is designed on the basis of this design concept, the second inductor 320 is placed in the wiring layer next to and above the wiring layer in which the first inductor 310 is placed.
In contrast, in the present embodiment, the first inductor 310 is positioned in the nth wiring layer, while the second inductor 320 is placed in the mth wiring layer (m≧n+2). Also, no inductor is provided in any of the wiring layers positioned between the nth wiring layer and the mth wiring layer to be positioned above the first inductor 310 . That is, the second inductor 320 is provided not in the wiring layer next to and above the wiring layer in which the first inductor 310 is formed but in the next wiring layer but one or more. Thus, the number of insulating films (insulating layers) positioned between the first inductor 310 and the second inductor 320 is increased relative to that in the case of the arrangement based on the above-described ordinary design concept, thereby increasing the insulation withstand voltage between the first inductor 310 and the second inductor 320 . This effect is particularly high in a case where, as in the present embodiment, the first inductor 310 is positioned in the first wiring layer while the second inductor 320 is positioned in the uppermost wiring layer.
Also, the first inductor 310 and the second inductor 320 can be formed by only changing the wiring patterns in the wiring layers. Therefore, changes in the semiconductor device manufacturing facilities and processing conditions can be avoided and full use of the manufacturing conditions of the existing semiconductor device manufacturing facilities can be made.
Also, the first circuit 100 , the second circuit 200 and the signal transmitting device 300 are formed on one substrate 10 in one process. As a result, the manufacturing cost of the semiconductor device is reduced and the semiconductor device is made small in size.
FIG. 2 is a sectional view of a semiconductor device according to the second embodiment. This semiconductor device is the same as the semiconductor device according to the first embodiment except that the second inductor 320 is positioned in the wiring layer 432 below the uppermost wiring layer 442 . In the example shown in FIG. 2 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires. With respect to the arrangement shown in FIG. 2 as well as with respect to the arrangement shown in FIG. 1 , “input electrical signals differ in potential from each other” means that the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other.
The same advantages as those of the first embodiment can also be obtained by the present embodiment. Also, since the first inductor 310 and the second inductor 320 are brought closer to each other, the signal transmission efficiency is improved and the power necessary for signal transmission in the signal transmitting device 300 is reduced.
FIG. 3 is a sectional view of a semiconductor device according to the third embodiment. The construction of this semiconductor device is the same as that in the first embodiment except that the first circuit 100 and the signal transmitting device 300 are formed on the substrate 10 and the second circuit 200 is formed on a substrate 20 . In the example shown in the figure, the first inductor 310 is connected to the first circuit 100 through the multilayer wiring layer 400 on the substrate 10 , while the second inductor 320 is connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 on the substrate 20 and bonding wires (not shown). With respect to the arrangement shown in FIG. 3 , “input electrical signals differ in potential from each other” means, for example, a case where the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other, a case where reference potentials (potentials representing 0) of electrical signals are different from each other, and a combination of these cases.
The number of wiring layers on the substrate 10 and the number of wiring layers on the substrate 20 are equal to each other in the example shown in the figure. However, these numbers may be different from each other. Also, while in the example shown in the figure the each layer and each wiring on the substrate 10 and the corresponding layer and wiring on the substrate 20 equal in thickness to each other, the layers and wirings on the substrates may differ in thickness from each other as in a modified example shown in FIG. 4 . In the example shown in FIG. 4 , the layers and wirings on the substrate 20 are thicker than those on the substrate 10 . However, the layers and wirings on the substrate 10 may alternatively be thicker than those on the substrate 20 .
The same advantages as those of the first embodiment can also be obtained by the present embodiment. Also, since the first circuit 100 and the second circuit 200 are respectively formed on different substrates 10 and 20 , a short circuit between the reference potential of the first transistors of the first circuit 100 and the reference potential of the second transistors of the second circuit 200 can be prevented even if the reference potentials are largely different from each other (for example, the difference between the reference potentials is 100 V or higher). Also, since the first inductor 310 is connected not to the second circuit 200 but to the first circuit 100 , the possibility of an increase in the potential difference between the first inductor 310 and the substrate 10 is low. Therefore, the occurrence of dielectric breakdown between the first inductor 310 and the substrate 10 can be reduced even though the first inductor 310 is placed in the lowermost wiring layer.
Also, the gate insulating films of the first transistors and the gate insulating films of the second transistors are made largely different from each other without using a complicated process.
FIG. 5 is a sectional view of a semiconductor device according to the fourth embodiment. This semiconductor device is the same as the semiconductor device according to the first embodiment except that the substrate 10 is a silicon on insulator (SOI) substrate; embedded insulating layers 18 are formed in the substrate 10 between the first region in which the first circuit 100 is formed, the second region in which the second circuit 200 is formed and the third region above which signal transmitting device 300 is formed; and the first, second and third regions are insulated from each other by the embedded insulating layers 18 .
The substrate 10 has a structure in which an insulating layer 14 and a silicon layer 16 are stacked in this order on a base substrate (e.g., a silicon substrate) 12 . The first transistors of the first circuit 100 and the second transistors of the second circuit 200 are formed in the silicon layer 16 . The embedded insulating layers 18 are embedded in the silicon layer 16 , and bottom portions of the embedded insulating layers 18 are in contact with the insulating layer 14 . In the example shown in FIG. 5 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires (not shown). With respect to the arrangement shown in FIG. 5 , “input electrical signals differ in potential from each other” means, for example, a case where the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other, a case where reference potentials (potentials representing 0) of electrical signals are different from each other, and a combination of these cases.
The same advantages as those of the first embodiment can also be obtained by the present embodiment. Also, since the first region in which the first circuit 100 is formed and the second region in which the second circuit 200 is formed are insulated from each other in the substrate 10 , the occurrence of a short circuit between the reference potential of the first transistors of the first circuit 100 and the reference potential of the second transistors of the second circuit 200 can be reduced even if the reference potentials are largely different from each other (for example, the difference between the reference potentials is 100 V or higher).
FIG. 6 is a sectional view of a semiconductor device according to the fifth embodiment. The construction of this semiconductor device is the same as that of the semiconductor device according to the fourth embodiment except that in the substrate 10 no embedded insulating layer 18 is provided between the first region in which the first circuit 100 is formed and the third region above which the signal transmitting device 300 is formed and the first region and the third region are electrically connected to each other. The first inductor 310 is connected to the first circuit 100 . In the example shown in FIG. 6 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires (not shown). With respect to the arrangement shown in FIG. 6 , “input electrical signals differ in potential from each other” means, for example, a case where the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other, a case where reference potentials (potentials representing 0) of electrical signals are different from each other, and a combination of these cases.
Also in the present embodiment, the first region and the third region are insulated from the second region in the substrate 10 . Therefore the same advantages as those of the fourth embodiment can be obtained. While first region and the third region are electrically connected to each other, the possibility of an increase in potential difference between the first inductor 310 and the substrate 10 is low because the first inductor 310 is connected not to the second circuit 200 but to the first circuit 100 . Consequently, the occurrence of dielectric breakdown between the first inductor 310 and the substrate 10 can be reduced even if the first inductor 310 is placed in the lowermost wiring layer 412 .
FIG. 7 is a sectional view of a semiconductor device according to the sixth embodiment. This semiconductor device is the same as the semiconductor device according to the fourth embodiment except that a plurality of embedded insulating layers 18 are provided in the substrate 10 below the first inductor 310 while being spaced apart from each other. In the example shown in FIG. 7 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires (not shown). With respect to the arrangement shown in FIG. 7 , “input electrical signals differ in potential from each other” means, for example, a case where the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other, a case where reference potentials (potentials representing 0) of electrical signals are different from each other, and a combination of these cases.
The same advantages as those of the fourth embodiment can also be obtained by the present embodiment. Also, because a plurality of embedded insulating layers 18 are provided in the substrate 10 below the first inductor 310 while being spaced apart from each other, the occurrence of an eddy current in the substrate 10 due to a magnetic flux formed by the first inductor 310 and the second inductor 320 can be reduced to lower the Q-value of the signal transmitting device 300 .
FIG. 8 is a sectional view of a semiconductor device according to the seventh embodiment. This semiconductor device is the same as the semiconductor device according to the sixth embodiment except that embedded insulating layers 19 separated from the insulating layer 14 are used in place of the embedded insulating layers 18 in contact with the insulating layer 14 . The embedded insulating layers 19 are of a shallow trench isolation (STI) structure and can be formed by the same process as that for forming device separating films for the first transistors of the first circuit 100 and the second transistors of the second circuit 200 . In the example shown in FIG. 8 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires (not shown). With respect to the arrangement shown in FIG. 8 , “input electrical signals differ in potential from each other” means, for example, a case where the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other, a case where reference potentials (potentials representing 0) of electrical signals are different from each other, and a combination of these cases.
The same advantages as those of the sixth embodiment can also be obtained by the present embodiment. The same advantages can also be obtained by using an oxide film obtained by local oxidation of silicon (LOCOS) in place of the embedded insulating layer 19 .
FIG. 9 is a sectional view of a semiconductor device according to the eighth embodiment. The construction of this semiconductor device is the same as that of the semiconductor device according to the first embodiment except that the embedded insulating layers 19 shown in the seventh embodiment are formed in the substrate 10 below the first inductor 310 . In the example shown in FIG. 9 , the second inductor 320 can be connected to the second circuit 200 via pads (not shown) formed in the uppermost wiring layer 442 and bonding wires (not shown). With respect to the arrangement shown in FIG. 9 , “input electrical signals differ in potential from each other” means that the amplitude (the difference between a potential representing 0 and a potential representing 1) of an electrical signal and the amplitude of another electrical signal are different from each other.
The same advantages as those of the first embodiment can also be obtained by the present embodiment. Also, the occurrence of an eddy current in the substrate 10 can be reduced to lower the Q-value of the signal transmitting device 300 . The same advantages can also be obtained by using LOCOS oxide film in place of the embedded insulating layer 19 .
While the embodiments of the present invention have been described with reference to the drawings, the described embodiments are only an illustration of the present embodiment and various arrangements other than those described above can also be adopted. | A semiconductor device includes a substrate, a transistor formed over the substrate, insulating layers formed over the substrate, a multilayer wiring formed in the insulating layers, a first inductor formed in the insulating layers, and a second inductor formed over the first inductor and overlapping the first inductor. The insulating layers contain a silicon, wherein at least the two insulating layers are formed between the first inductor and the second inductor, and the first inductor and the second inductor are a spiral wiring pattern. | 7 |
BACKGROUND OF THE INVENTION
The field of the present invention is medical equipment, and more particularly, equipment for bedside patient care, and still more particularly, equipment for providing tubes, ducts, lines and the like to patients for transporting oxygen, medicament, or for other treatment.
In hospitals and particularly intensive care units, it is not uncommon for patients to require breathing assistance, a supply of pure oxygen, nutrients, medicament or other treatment requiring the use of tubes, ducts, lines and the like which are attached on or about the patient. Also, in the treatment of hypothermia by a convective apparatus, warmed air must be delivered to an inflatable thermal blanket through a large diameter, flexible duct.
In the case of tubes or ducts providing oxygen from breathing apparatus or warmed air from a blower, the tube or duct may simply be draped over the side of the bed, in which case it may tend to become detached from the patient or patient apparatus to which it is connected. To overcome this disadvantage, it has been proposed to use a generally L-shaped tube support apparatus having a lower portion adapted to fit under a mattress or between a mattress and a frame, and an upwardly extending portion having a notch at the top adapted to support and lock a tube or duct in a fixed position relative to the connection to which the tube or duct is attached, without imparting any axial strain or disconnecting force on the connection. Such apparatus, however, are bulky and inconveniently space-consuming when not in use, as for example during storage or transport.
SUMMARY OF THE INVENTION
The present invention is directed to a tube support having the advantage of enhanced space saving ability for storage and transport, whereby hospital operations can be improved. To that end, there is provided a base member configured to engage a surface, a tube support member comprising a tube support shoulder at one end thereof, and a pivotal attachment extending between the base member and the tube support member for pivotally connecting the base and tube support members.
It is, therefore, an object of the present invention to provide a tube support which is readily configurable from an operational to a storage or transport position, for enhanced space-saving ability and improved hospital operations.
BRIEF DESCRIPTION OF THE DRAWING
These and other objects, advantages and features of the invention will be more readily appreciated when read in conjunction with the accompanying drawing, in which:
FIG. 1 is a perspective view of a hinged tube support constructed in accordance with the present invention showing the support member in an operational position.
FIG. 2 is a perspective view of the hinged tube support apparatus shown in FIG. 1 showing the apparatus in a storage position.
FIG. 3 is a truncated diagrammatic plan view of the pivotal attachment of the apparatus shown in FIGS. 1 and 2 showing the apparatus in an operational pivotally locked position.
FIG. 4 is a truncated diagrammatic plan view of the apparatus shown in FIGS. 1 and 2 showing the apparatus in a storage position.
FIG. 5 is a truncated diagrammatic plan view of the apparatus shown in FIGS. 1 and 2 showing the apparatus in an intermediate pivotally unlocked position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to FIGS. 1 and 2, a medical apparatus comprising a hinged tube support 2 is shown. The hinged tube support includes a bed attachment or base member 4 having a pair of ears or trunnion plates 6 formed at one end thereof, a tube support member 8 with an arcuate or "U"-shaped tube support shoulder 10 at the upper end thereof configured to support and grip the sides of a tube or duct, and a pair of trunnions 12 at the lower end thereof formed by a pair of notches 14 disposed proximate to the lower end of the tube support member 8. The bed attachment 4 member, including the ears or trunnion plates 6, and the tube support member 8 are substantially planar and formed from an appropriate sheet material such as molded plastic, sheet metal or other suitable structurally rigid material, provided, however, that the material is sufficiently flexible to permit outward movement of the ears or trunnion plates 6 so as to enable detachment of the bed attachment and tube holding members from one another.
Referring now to FIGS. 3-5, the ears or trunnion plates 6 and trunnions 14 form, in combination, a pair of pivotal attachments or connections 20. The trunnion 14 thus defines a key member which is rotatably mounted in an arcuate keyway 22 formed in the trunnion plate 6. The arcuate keyway is defined by a pair of opposing arcuate guide surfaces 24 and respective pairs of stop surfaces 26 extending from the respective ends of the arcuate guide surfaces 24 to a central keyway area 28. As shown, the key member or trunnion 14 extends substantially between the arcuate guide surfaces 24 such that the surfaces 24 guide and direct the rotational motion of the key member or trunnion 14 within the keyway 22.
As shown in the figures, the trunnion or key member 14 is substantially rectangular, and opposing pairs of the stop surfaces 26 extending from the arcuate surfaces toward the central keyway area 28 are substantially coplanar and spaced from each other substantially the width of the key member or trunnion 14 so as to define a pair of key slots at the ends of the arcuate path defined by the arcuate guide surfaces 24. The key slots are positioned to provide a range of rotational angles between which the base and tube support members may be rotated. For example, the key slots may be positioned to prevent rotation of the base and tube support members beyond a storage position of about 0° relative angle and operational position of not less than about 90° relative angle.
Additionally, a lock slot 30 may be provided for locking the key member or trunnion 14 against rotation. The lock slot 30 is formed by extending the associated stop surface 26 radially beyond the arcuate surface 24 so as to define one side of the lock slot 30, and forming a parallel lock surface 32 spaced from the stop surface 26 a distance sufficient to accept the trunnion or key member 14 and extending radially beyond the associated arcuate guide surface 24. In this manner, the trunnion or key member 14 may be translationaly positioned in the lock slot 30 so as to prevent its further rotation.
The pivotal connection 20 may also be thought of as including a generally rectangular key member rotatably positioned in a divided cylindrical keyway defined by a generally cylindrical aperture truncated by a pair of opposing generally pie-shaped stop members 40. As shown in FIGS. 3-5, the apices of the opposing pie-shaped stop members 40 are spaced from each other a distance sufficient to permit the key member or trunnion 14 to align with opposing stop surfaces 26 of the opposing stop members 40 at the ends of the rotational path defined by the stop members 40 and the cylindrical keyway 22.
Thus, a novel medical apparatus comprising a hinged tube support having the advantages of collapsibility to facilitate storage and transport has been disclosed. While an application and embodiments of this invention have been shown and described, it should be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the appended claims. | A tube support for facilitating bedside attachment of a life support tube or duct includes a base member configured to rest on a surface, a tube support member having a tube support shoulder at one end thereof and a pivotal attachment extending between the base member and the tube support member for pivotally connecting the base and tube support members. | 8 |
BACKGROUND OF THE INVENTION
The present invention is primarily concerned with a process for the efficient preparation of enantiomers of a substituted fluorenyloxyacetic acid.
Certain fluorenyloxyacetic acid useful for treating brain edema are disclosed in U.S. Pat. No. 4,316,043. These acetic acid have a chiral center and exist as racemates and individual enantiomers.
DESCRIPTION OF THE INVENTION
The present invention is concerned with a direct process for the efficient preparation of a substituted fluorenyloxyacetic acid which includes the step of forming a chiral center at an intermediate stage of the process by the alkylation of a hydrocarbonyloxy-6,7-dichloro-2-propyl-2,3-dihydro-1H-inden-1-one in the presence of chiral phase transfer catalyst and a significant amount of an achiral, non-ionic surfactant as co-catalyst. The presence of the surfactant during the chiral alkylation step is important to the efficient operation of the process. Although assymetric induction may be achieved in some degree by the use of the chiral catalyst by itself, the enantiomeric efficiency is enhanced by the addition of a relatively small amount of an achiral, non-ionic surfactant co-catalyst to the chiral phase transfer alkylation step of the process. Thus, by incorporating a non-ionic surfactant in the step, not only the amount of expensive chiral catalyst required is substantially reduced, but the reaction time is reduced and the ratio of desired isomer to undesired isomer increased without adversely affecting the yield of product obtained.
Thus, the process of the present invention useful in the preparation of a compound of the formula: ##STR1## comprises:
(a) treating a compound of the formula: ##STR2## with 1,3-dichlorobutene-2 under liquid-liquid phase transfer condition in a basic medium in the presence of a chiral catalyst and an achiral, non-ionic surfactant co-catalyst to obtain a preponderance of the (R)-enantiomer of the trichloro ketone of the formula: ##STR3## wherein R is a hydrocarbonyl radical selected from C 1 -C 6 -alkyl or phenyl C 1 -C 6 -alkyl;
(b) treating said trichloro ketone enantiomer with concentrated sulfuric acid and a small amount of water at a temperature of from 0°-25° C. to obtain a reaction mixture containing a-dichloro-diketone enantiomer of the formula: ##STR4##
(c) increasing the temperature of the reaction mixture to effect cyclization and production of a fluorenone compound of the formula: ##STR5##
(d) treating said fluorenone compond with aluminum chloride to obtain a hydroxy-fluorenone compound of the formula: ##STR6##
(e) treating said hydroxyfluorenone compound with a haloacetic ester in the presence of a base to obtain an oxyacetic acid ester derivative of the formula: ##STR7## wherein R 1 is lower alkyl of from C 1 -C 6 ;
(f) hydrolyzing said ester to produce a fluorenyloxyacetic acid compound of the formula: ##STR8##
(g) and crystallizing said fluorenyloxyacetic acid compound to obtain the (R) isomer.
The chiral phase transfer alkylation of step (a) of the subject process is remarkably enhanced by the presence in the reaction mixture of a small amount, i.e., from about 1-10% by weight of an achiral non-ionic surfactant co-catalyst based on the weight of the starting indanone compound. When this step is compared to the process of asymmetric phase transfer alkylation with no surfactant added to the chiral catalyst, it is found that addition of a poly(ethylene glycol alkyl ether or alcohol) in the above indicated amounts, preferably about 4% by weight of the starting indanone, substantially reduces the reaction time, effects a higher enantiomeric efficiency (e.e.), reduces the amount of chiral catalyst required to 1/3 of the amount using no surfactant without adversely affecting the yield of alkylated indanone which is preferably not isolated, but used directly after washing out catalyst decomposition products, preferably as a toluene solution of compound III hereinabove.
In the next step (b), the solution of product III is hydrolyzed by treatment with concentrated sulfuric acid and sufficient water to provide 2 moles of water/mol of III with resultant production of compound IV. In step (d), the intermediate product IV is cyclized without isolation of compound IV by raising the temperature of the reaction mixture containing concentrated sulfuric acid to about 65°-75° C. to produce compound V in essentially quantitative yield.
The chiral catalyst employed in step (a), i.e., the chiral alkylation of the substituted indanone II is known to take place in the presence of approximately an equimolar amount of catalyst.
Any suitable chiral catalyst may be used and dihydro-N-benzylcinchonidinium or N-benzylcinchonidinium halide wherein benzyl is substituted or unsubstituted or wherein substituents (1 or 2) are selected from CF 3 , halo, C 1 -C 3 , alkyl, OCH 3 , CN, and the like including 3,4-dichlorobenzyl cinchonidinium chloride and p-trifluoromethyl cinchonidinium bromide is preferred. Dihydro-3,4-dichlorobenzyl cinchonidinium chloride and (ii) dihydro-p-trifluoromethyl benzyl cinchonidinium bromide can also be used if cleaved. Using these chiral catalysts, formula III compound containing the (R) isomer predominantly is obtained; the ratio of (R); (S) isomer will range from 75:25 to 90:10 higher.
As the co-catalyst promoter, any achiral non-ionic surfactant may be effectively used to enhance the chiral effect of the catalyst employed. Preferably the surfactants are poly(ethylene glycol, ethers and alchols). Such compounds are commercially available under the names Triton X (of the formula ##STR9## wherein x is 3 to 70 Triton X-405 where is 40 or Triton X-100 where is 10), Triton N (of the formula C 9 H 19 O--(CH 2 --CH 2 ) n OH) where n is 4 to 100 poly(ethylene glycol) of mol wt. 200 to 1500, poly(ethylene glycol methyl ether) of mol wt. 350 to 1400 and the like.
The following examples are for purposes of illustration and are not in any way intended to set limits in the invention claimed. Temperatures are expressed in degrees Celsius unless otherwise noted.
EXAMPLE 1
Chiral Phase Transfer Alkylation
6,7-Dichloro-2-(3-chloro-2-butenyl)-2,3-dihydro-5-methoxy-2-propyl-1-H-inden-1-one (4) ##STR10##
Materials
9.9 g; 36.2 mmole: 6,7-Dichloro-2,3-dihydro-5-methoxy-2-propyl-1H-inden-1-one (3)
15 g; 120 mmole: 1,3-Dichloro-2-butene (3.3 mole/mole of 3; DuPont, a 4/1 mixture of trans/cis-butenes)
5.4 g; 11 mmole: 3,4-Dichlorobenzylcinchonidinium chloride Cl 2 BCDC; 30 mole % based on 3, N.B. β11967-288)
0.4 g: Triton X-405 (4 wt. % based on 3, Technicon Corp.; 70% aqueous solution)
300 ml: Toluene
60 ml: Sodium hydroxide, 50% aqueous solution
A 500 ml stirred autoclave was charged with 300 ml of toluene, 9.9 g of 3, 15 g of 1,3-dichloro-2-butene, 5.4 g of Cl 2 BCDC, 0.4 g of Triton X-405 and 60 ml of 50% aqueous sodium hydroxide. The reactor was evacuated (22" Hg) and flushed with nitrogen three times. Then the mixture was vigorously stirred for 20 hours at 20° C. under 2-5 psi of nitrogen.
After completion the reaction mixture was transferred into a separatory funnel. The reactor was rinsed with a mixture of 180 ml of water and 100 ml of toluene which was combined with the reaction mixture. The opaque aqueous bottom layer was cut. The toluene layer was washed at room temperature with 100 ml 4N HCl/100 ml methanol, 100 ml 4N HCl and finally with 100 ml H 2 O.
The final volume of toluene was 410 ml, containing 3.4 g of E-isomer of 4 and 9.8 g of Z-isomer of 4. The enantiomer ratio was 81/19 of (+/-) and the overall yield was essentially quantitative.
The experiment is repeated using p-Trifluoromethylbenzylcinchonidinium catalyst and the enantiomer ratio was 90/10 of (+/-) with essentially quantitative overall yield.
EXAMPLE 2
Hydrolysis and Cyclization
5,6-Dichloro-1,2,9,9a-tetrahydro-7-methoxy-9a-propyl-3H-fluoren-3-one (6) ##STR11##
Materials
20 g; 55.3 mmole: 6,7-Dichloro-2-(3-chloro-2-butenyl)-2,3-dihydro-5-methoxy-2-propyl-1H-inden-1-one (4) (783 ml of a toluene solution, containing 25.55 mg/ml of 4; 80/20 enantiomer ratio).
55 ml: Concentrated; sulfuric acid
60 ml: 1N hydrochloric acid
2 ml: Water (2 moles/mole of 4)
160 ml: Toluene
200 ml: 5% Aqueous sodium bicarbonate
The solution of 4 in toluene from the last step was concentrated via distillation in a 250 ml 3 neck r.b. flask equipped with mechanical stirring, addition funnel and a distillation head to a total volume of 55 ml. At the end of the distillation the head temperature was 111°-112°. After distillation an N 2 -inlet was connected to the flask and the stirred solution was cooled to 0° C. with an ice-methanol bath (bath temperature -10° C.). H 2 SO 4 (50 ml) was added via the addition funnel at the rate of 10 ml/min maintaining a temperature range of 0°-5° with ice-methanol cooling. Complete addition of H 2 SO 4 afforded a dark colored solution. The ice-methanol bath was replaced by an ice water bath and the reaction mixture was stirred at 0°-5° for 1.5 hours. Complete disappearance of starting material was observed by L.C.
At the end of 1.5 hours, the ice-cooling was removed and 2 ml of water was added over a period of 30 seconds to the reaction mixture. The temperature of the reaction mixture went up from 5° to 15° during the addition. The reaction mixture was heated to 60°-65° wherein a mild exotherm occurs and maintains the reaction of 65°-70° for about 30 minutes.
The reaction mixture was cooled to 25° C. and then slowly poured over 20 minutes into a stirred mixture of 150 ml of toluene and 275 ml of water allowing the temperature to rise to 35°. The residue in the flask was transferred successively with 5 ml concentrated H 2 SO 4 , and 2 times 10 ml of 1:1 mixture of toluene and water. The heterogeneous mixture was stirred for 15 minutes at 50° and then allowed to separate at 50°. The bottom aqueous layer which has a slightly milky appearance was separated from the top toluene layer. The aqueous layer which contained 100 mg of product by L.C. assay was discarded. To the toluene layer containing the product was added 200 ml of a 5% sodium bicarbonate solution and the heterogeneous mixture was stirred for 60 minutes at 20°-25° and then allowed to settle. The bottom aqueous layer which has a slightly milky appearance was separated from the top toluene layer. The aqueous layer which contained 40 mg of product by L.C. assay was discarded. To the toluene layer containing the product was added 60 ml 1N HCl. The heterogeneous mixture was stirred for 30 minutes at 20°-25° and then allowed to settle. The bottom aqueus layer was separated from the top toluene layer. The aqueous layer which contained 16 mg of product by L.C. assay was discarded.
The top toluene layer containing the product was carried through to the next step. The wet toluene solution is stable and may be stored for several days without loss of product. The volume of the toluene solution was 200 ml containing 16.7 g (51.4 mmole, 93% yield) of product 6.
EXAMPLE 3
O-Demethylation
5,6-Dichloro-1,2,9,9a-tetrahydro-7-hydroxy-9a-propyl-3H-fluoren-3-one ##STR12##
Materials
15.43 g; 47.4 mmole: Approximately 200 ml solution of 5,6-dichloro-1,2,9,9a-tetrahydro-7-methoxy-9a-propyl-3H-fluoren-3-one 3 in toluene.
22.1 g: 166 mmole: Aluminum chloride (3.5 moles per mole of 6)
34 ml: Water
30 ml: Toluene
The volume of the reaction mixture is adjusted to 230 ml with 30 ml of toluene. The toluene solution is dried by azeotropic removal of water at reflux to a KF of 0.1%. The solution is cooled to room temperature (20° C.) and the aluminum chloride is added over a period of 5 minutes. The temperature rises to 37° C. The mixture is heated to 45°-48° C. and aged at that temperature for 1.5 hours.
Completion of the demethylation is monitored by LC.
The reaction is quenched at 45°-47° C. by addition of 34 ml of water. The temperature rises to 75° C. The grey reaction mixture is then heated to reflux and aged at reflux for 1 hour. The reaction mixture is then dried by azeotropic removal of water.
EXAMPLE 4
O-Alkylation
[(5,6-Dichloro-2,3,9,9a-tetrahydro-3-oxo9a-propyl-1H-fluoren-7-yl)oxy]Acetic Acid Ethyl Ester ##STR13##
Materials
Approx. 14.7 g; 47.4 mmole: 5,6-Dichloro-1,2,9,9a-tetrahydro-7-hydroxy-9a-opyl-3H-fluoren-3-one approx. 230 ml of toluene.
3.9 g: Triton X-405, 25 wt.% based on Indanone 3.
29.5 g; 213 mmole: Potassium carbonate (1 mole per mole of aluminum chloride and 3 used in the previous step).
2.3 g; 15.3 mmole: Sodium iodide
9.57 g; 78.1 mmole: Ethyl chloroacetate
250 ml 2.5N Hydrochloric acid
250 ml 1.0N Hydrochloric acid
To the reaction mixture from the previous step is added 3.9 g of Triton X-405, 29.5 g of potassium carbonate, 2.3 g of sodium iodide and 9.57 g of ethyl chloroacetate. The reaction mixture is heated to reflux and water is azeotropically removed. The reaction is aged for 4 hours at reflux while the water is removed. The reaction mixture is cooled to room temperature and 250 ml of 2.5N HCl is slowly added (CO 2 evolution!). The mixture is heated to 70°-75° C. and stirred for 0.5 hours. The bottom aqueous layer is cut at 70°-75° C. and discarded. The toluene layer containing the product is washed with 250 ml 1N HCl at 75° C. The toluene layer is cooled room temperature (20° C.). Yield 18.2 g (96.6% from 4).
EXAMPLE 5
Ester Hydrolysis
[(5,6-Dichloro-2,3,9,9a-tetrahydro-3-oxo-9-propyl-1H-fluoren-7-yl)oxy]Acetic Acid Potassium Salt ##STR14##
Materials
Approx. 18.2 g; 45.8 mmole: [(5,6-2,3,9,9a-tetrahydro-3oxo-9a-propyl-1H-fluoren-7-yl)oxy]acetic acid ethyl ester in approx. 230 ml of toluene from previous step.
101 ml: 1.17N Potassium hydroxide (2.5 mole KOH/mole of 8)
165 ml: Water
Water (165 ml) and 101 ml of 1.17N potassium hydroxide solution (2.5 mole KOH/mole of 5) are added to the toluene solution from the previous step. After mixing, the pH of the aqueous phase is 13.2. The mixture is refluxed for 2 hours and then cooled to 75° C. The bottom aqueous layer containing the product is separated and cooled to 20° C. Yield 15.7 g of 6 (as acid) (89.8% from 3), (R/S) Isomer ratio=80.5/19.5.
In the instance where p-trifluoromethybenzycinchonidinium catalyst is used as the catalyst the final product has an (R/S) isomer ratio of (90/10). | An improved method for the direct preparation of an enantiomer of a substituted fluorenyloxyacetic acid including the enhancement of a chiral phase transfer alkylation step in the synthesis using a non-ionic surfactant as co-catalyst. The substituted fluorenyloxyacetic acid is useful in the treatment of brain edema. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates to the field of domestic appliances, particularly the field of blenders, juice extractors or the like.
BACKGROUND OF THE INVENTION
[0002] Juice extractors have become increasingly popular over the years. These devices extract juice from fresh fruits and/or vegetables and provide people with fresh, healthy, and all natural beverages.
[0003] While numerous health benefits are associated with juicing, the extraction process is often known to be time-intensive, difficult, and messy. Typically, a user must: gather necessary fruit and/or vegetables, wash and cut the food to proper size, insert all food into the extractor, dispose of the organic waste, disassemble and clean the extractor parts, and lastly reassemble the extractor. Thus, many users are left frustrated and demanding a better option. Moreover, a correct portion size is not easily enforced due to no standard amount of fruit and/or vegetables allowed to be juiced during a single session. It is also known that devices have been made that simply blend fruit and/or vegetables into a pulp and provide both the pulp and juice mixed together for consumption. However, many people prefer a pulp-free beverage.
[0004] In a fast-paced world, there is an increasing demand for healthy beverages that can be prepared easily, quickly, and most importantly with minimal cleanup. Furthermore, people would greatly benefit from a properly portioned, fresh beverage from the comfort of their own home. For the foregoing reasons, there is a need for a machine that can produce personal juice beverages from fresh fruit and/or vegetables.
BRIEF SUMMARY
[0005] The present invention is directed to a personal blender and juicer system that meets these needs.
[0006] Specifically, it is an aspect of the invention to provide a food blending and pressing apparatus. The food blending and pressing apparatus includes a housing that covers moving machinery used for blending and pressing food and/or beverage in a removable container located in a container chamber. The upper face of the bottom of the container chamber preferably includes an anti-rotational surface so that when the container with a preferably complimentary anti-rotational bottom surface is inserted into the container chamber, the container is secured. A start button is preferably pressed by a user to initiate the automatic blending and pressing process. A blending tool is rotated by a driving source which blends food and/or beverage in the container to a desired consistency while a cover hermetically seals the container during the blending process. A primary elevator assembly is used to raise and lower a shaft attached to the blending tool during the blending process. The primary elevator is preferably driven by a spring-loaded lever. A secondary elevator assembly is used to raise and lower the cover during the blending and pressing. The secondary elevator is preferably driven by an inflatable and deflatable airbag. Once the blending process is complete, the cover is used to press the food and/or beverage towards the bottom of the container causing liquid to flow through an outlet in the container. The shaft is preferably connected to the driving source as well as to the secondary elevator by quick release connectors for quick removal and cleaning. The cover is preferably connected to the secondary elevator by a quick release connector for quick removal and cleaning.
[0007] Furthermore, it is another aspect of the invention to provide a container. The preferably cylindrical container has an upper opening to afford food and/or beverage, a blending tool and a cover. The top diameter of the container is preferably larger than that of the bottom diameter to allow for efficient stacking and a funnel is preferably connected to the top of the container to allow the cover to properly seal upon entering the upper opening of the container. The sides of the container preferably have vertical concave grooves extending half-way down to allow pressure to escape when the cover is inserted into the container. A spacer may be mounted at the center of the upper face of the bottom of the container to prevent the blending tool from contacting the bottom of the container during operation. The container preferably includes an anti-rotational surface on the bottom so that when inserted into a food blending and pressing apparatus with a complementary anti-rotational surface, the container is properly secured. The container is removably inserted into a food blending and pressing apparatus. Food and/or beverage is first blended and then pressed in the container, forcing liquid to flow through an outlet fitted with a filter in the bottom of the container into an external cup. The outlet is preferably connected to a secondary outlet extending out to a spout, thereby allowing liquid to be received in the external cup placed adjacent to the container. The outlet is preferably covered by a valve that prevents liquid from passing out of the container due to gravity. Furthermore the outlet and open top are preferably covered with a plastic film to prevent contamination prior to use.
[0008] It is another aspect of the invention to provide a method of blending and pressing food and/or beverage in a container wherein food and/or beverage is placed on a container, the container is secured in a container chamber, a shaft with a blending tool is lowered into the container while a cover is also lowered into the container to seal the container, the shaft and the blending tool are rotated by a driving source thereby blending the food and/or beverage, the shaft and the blending tool are moved up and down as necessary until a desire consistency is met, the cover is lowered further into the container thereby forcing liquid through an outlet in the container and into an external cup, followed by the cover, shaft, and blending tool being retracted, and then removing the container from the chamber. The cover and blending tool may be removed for cleaning.
[0009] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention is generally shown by way of reference to the accompanying drawings in which:
[0011] FIG. 1 is a perspective view of one embodiment of a food blending and pressing apparatus with both primary and secondary doors open, the container chamber empty, and the blending tool and cover removed;
[0012] FIG. 2 is a perspective view similar to FIG. 1 with the blending tool and cover inserted;
[0013] FIG. 3 is a perspective view similar to FIG. 2 with the container inserted in the container chamber;
[0014] FIG. 4 is a perspective view similar to FIG. 3 with both primary and secondary doors closed and an external cup placed next to the food blending and pressing apparatus;
[0015] FIG. 5 is a frontal cross sectional view of the food blending and pressing apparatus of FIG. 3 showing the blending tool and cover fully refracted;
[0016] FIG. 6 is a frontal cross sectional view similar to FIG. 5 showing the blending tool and cover are partially extended downward wherein the cover contacts the container;
[0017] FIG. 7 is a frontal cross sectional view similar to FIG. 6 showing the blending tool and cover extended downward wherein the blending tool contacts the spacer;
[0018] FIG. 8 is a side cross sectional view of the food blending and pressing apparatus of FIG. 5 showing the airbag apparatus deflated;
[0019] FIG. 9 is a side cross sectional view of the food blending and pressing apparatus of FIG. 7 showing the airbag inflated;
[0020] FIG. 10 is a perspective view of the blending tool and cover assembly of the blending and pressing apparatus shown in FIG. 2 ;
[0021] FIG. 11 is a perspective view of one embodiment of a container in accordance with the present invention;
[0022] FIG. 12A is a side cross sectional view of the container shown in FIG. 11 ;
[0023] FIG. 12B is an enlarged side cross sectional view of the spout shown in FIG. 12A with liquid exiting the spout;
[0024] FIG. 13 is an exploded view of the container shown in FIG. 11 ;
[0025] FIG. 14 is a perspective view of another embodiment of a container in accordance with the present invention, a plastic film is shown covering the open top;
[0026] FIG. 15 is a perspective view of the bottom of the container shown in FIG. 14 ;
[0027] FIG. 16 is a cross sectional view of the container shown in FIG. 14 ; and
[0028] FIG. 17 is a perspective view of another embodiment of a container in accordance with the present invention, the sides are angled such that the containers are stackable.
DETAILED DESCRIPTION
[0029] Referring to the drawings, FIGS. 1-4 generally depict a food blending and pressing apparatus 100 comprising a removable container 200 with an open top 201 received in a container chamber 101 , a cover 111 used for both sealing open top 201 and pressing the contents in container 200 , and a blending tool 112 used for chopping, mixing, or liquefying food in container 200 .
[0030] FIG. 11 provides a view of one embodiment of container 200 . Container 200 further comprises sides 202 which may be generally cylindrical and a bottom 203 . For example, container 200 is constructed to hold food and/or beverage before, during, and after the blending and pressing process. An outlet 204 is mounted through bottom 203 to allow liquid to flow out of container 200 when pressurized. Outlet 204 has a filter 207 which provides a sieve-like configuration to prevent solids from flowing out of container 200 during the blending and pressing process. A spacer 205 may be mounted on the upper surface of bottom 203 . As shown in FIG. 7 , spacer 205 prevents blending tool 112 from hitting and thus damaging bottom 203 during operation. The upper face of spacer 205 is a bearing surface 206 and therefore allows blending tool 112 to spin freely while contacting bearing surface 206 .
[0031] In one example of container 200 , all parts of container 200 are manufactured with non-hazardous materials conforming to international food safety standards. The materials used to construct it may be such that container 200 is discarded after a single use. Likewise, in another example, the materials used to construct container 200 may be such that it is reusable after cleaning by increasing the thickness and strength of such materials.
[0032] FIG. 10 illustrates one embodiment of cover 111 . Cover 111 is used to hermetically seal open top 201 of container 200 and also to press food and/or beverage toward bottom 203 forcing liquid to flow out through outlet 204 . For example, a secondary elevator assembly 109 is attached to cover 111 ( FIGS. 5-7 ) to provide the means to vertically reciprocate cover 111 up and down as needed during the blending and pressing process. The reciprocating motion of secondary elevator assembly 109 may be driven by deflating and inflating an airbag apparatus 116 . A releasable connector 118 may be integrated into cover 111 to allow cover 111 to be removed for cleaning ( FIG. 10 ).
[0033] FIG. 10 also illustrates one embodiment of blending tool 112 . Blending tool 112 is attached to the bottom end of a shaft 110 . Shaft 110 is extended through the center of cover 111 and includes a connector 117 on the top end of shaft 110 that is connected to a driving source 114 using a belt 113 to rotate blending tool 112 . In the preferred embodiment, connector 117 has a hex shaped cross-section and is integrated into shaft 110 . A sanitary seal 121 is attached to cover 111 , hermetically sealing cover 111 about shaft 110 thereby preventing air, liquid, or solids escaping from container 200 ( FIG. 7 ). A primary elevator assembly 108 is attached to shaft 110 to provide the means to vertically reciprocate blending tool 112 up and down as needed during the blending and pressing process ( FIGS. 5-7 ). The reciprocating motion of primary elevator assembly 108 may be driven by a spring-load lever 115 ( FIGS. 8-9 ). Connectors 117 and 119 may be releasable to allow blending tool 112 and shaft 110 to be removed for cleaning. Blending tool 112 may include radially extended cutting blades 120 with sharpened edges, pointed tips, and one or more bends along the surface of the cutting elements.
[0034] FIGS. 1-4 generally illustrate the process of installing components into food blending and pressing apparatus 100 . FIG. 1 shows a housing 107 used to protect the components. A primary door 103 and latch 104 may be opened to provide access to blending tool 112 and cover 111 ( FIG. 2 ). A secondary door 102 and latch 105 may be opened to provide access to container chamber 101 . Blending tool 112 and cover 111 are inserted into food blending and pressing apparatus 100 as shown in FIG. 2 . Container 200 is charged with food and inserted into food blending and pressing apparatus 100 as shown in FIG. 3 . FIG. 4 shows one embodiment where primary door 103 and secondary door 102 are closed and an external cup 300 next to food blending and pressing apparatus 100 . During the food blending and pressing process, juice may be extracted out through spout 213 into external cup 300 for consumption ( FIGS. 12A-12B ). Spout 213 may be connected to a secondary outlet 212 which may be connected to outlet 204 .
[0035] Sides 202 of container 200 may be constructed in an inverted frustaconical shape such that the diameter of open top 201 is larger than the diameter of bottom 203 ( FIG. 17 ). This allows container 200 to be stacked in another container 200 efficiently when empty. Container 200 may include a funnel 208 attached to open top 201 thereby correcting small misalignments when cover 111 is lowered into container 200 . Container 200 may include one or more vertical pressure relief grooves 209 ( FIG. 11 ) which allows pressure to escape container 200 until cover 111 is lowered below the bottom of pressure relief grooves 209 . This allows cover 111 and blending tool 112 to be lowered into container 200 without forcing liquid through outlet 204 . Also, a valve 211 may cover outlet 204 to prevent liquid from flowing out of container 200 until pressure is applied inside container 200 , forcing liquid through outlet 204 ( FIG. 15 ).
[0036] Bottom 203 may include an anti-rotational surface 210 in the shape of a downwardly protruding triangular-shaped vane ( FIG. 15 ). Anti-rotational surface 210 is complementary to a concavely shaped anti-rotational surface 122 located in the bottom of container chamber 101 ( FIG. 1 ) and such that when container 200 is inserted in container chamber 101 , container 200 is unable to rotate. A plastic film 214 may be fixed to both open top 201 ( FIG. 14 ) and outlet 204 ( FIG. 15 ) of container 200 to prevent contamination prior to use.
[0037] FIGS. 14-16 generally illustrate an alternative configuration to container 200 . No spout 213 or secondary outlet 212 are used. Outlet 204 may allow liquid to flow out of container 200 into an external cup (not shown) directly below container 200 .
[0038] In the preferred embodiment, container 200 is filled with food and/or beverage and then placed in container chamber 101 . A start button 106 is pressed by the user to initiate the blending and pressing process. The blending and pressing process begins by lowering shaft 110 along with attached blending tool 112 into container 200 while also lowering cover 111 into container 200 until cover 111 contacts container 200 , thereby sealing open top 201 . The food and/or beverage is blended by rotating shaft 110 and blending tool 112 using driving source 114 . Shaft 110 and blending tool 112 are lowered and raised as necessary while rotating in order to properly blend the contents and then rotation is halted once a preferred consistency is met. Cover 111 is then lowered further into container 200 , pressing food and/or beverage towards bottom 203 and forcing liquid through outlet 204 . After the desired liquid has been extracted from the food and/or beverage, cover 111 , shaft 110 , and blending tool 112 are fully retracted and container 200 is removed from container chamber 101 . Cover 111 and blending tool 112 may be removed from food blending and pressing apparatus 100 for cleaning.
[0039] Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained therein. Any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specified function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. §112, ¶6. In particular, the use of “step of” in the claims is not intended to invoke the provisions of 35 U.S.C. §112, ¶6.
[0040] The reader's attention is directed to all papers and documents which are filed concurrently with his specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All features disclosed in this specification (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. | The invention concerns a personal juice extractor system including a blending and pressing apparatus where a user places a container charged with food or beverage or any combination thereof in a container chamber. After the start button is pressed, a blending tool attached to a shaft along with a cover are lowered into the container until the cover seals the open top of the container. The blending tool is axially rotated until a desired consistency is achieved. The cover then presses down on the blended contents, forcing liquid to flow out an outlet in the bottom of the container and into an external cup for consumption. The cover, shaft, and blending tool are retracted and then the container is removed from the container chamber and discarded or cleaned for reuse. | 0 |
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to face masks and more particularly to means for preventing fogging of optical aids used by a wearer of a surgical face mask.
2. Technical Considerations
Face masks are generally worn to reduce the amount of contamination either exhausted from or inhaled by the wearer. Among these are masks of the sterile, surgical variety, necessities for hospital operating rooms. Surgical face masks are worn by surgeons and others around an operation to substantially prevent the contamination and infection of the patient from the wearers during operations. Effective and comfortable masks are available which are both disposable and nondisposable. The advantage of disposability is the elimination of the expensive sterilizing procedure and inherent danger of cross-contamination.
Surgical masks are generally lightweight in construction and contain several features designed for adaptation to an individual wearer's features. There is often incorporated within the mask, along the upper edge, an elongated, deformable metal strip having sufficient stiffness to retain any shape given it. In this way, the upper portion of the mask may be contoured to the wearer's face to improve the upper edge fit. A relatively thin strip of soft foam material is sometimes found along this upper edge to increase the comfort of the wearer.
Although the upper edge may be contoured in a variety of facial shapes to most closely approximate the wearer's features, it is inadequate to prevent the wearer's breath from rising between his or her face and the mask. Since these masks are not designed to obstruct breathing, but rather to provide a breath filter, some breath exhausts through the upper portion of the mask into the vicinity of the wearer's eyes. The breath being warm and moist, holds fluid vapor which readily condenses on cooler objects. Such cooler objects may be present in the air-conditioned operating rooms in the form of glass lenses of optical aids used by the surgeons and assistants. Such optical aids include spectacles, surgical loupes and surgical microscopes.
The exhaust of exhaled breath is resisted to some degree by the mask itself, prompting some breath to flow under the mask edges. Because warm air rises, the wearer's breath also has a natural tendency to rise under the upper mask edge and through the upper mask surface area producing fogging of the optical aids positioned in the vicinity of the wearer's eyes. This obscuration of the wearer's vision is a nuisance at best and a hazard at worst. This shortcoming of the prior art mask often requires the surgeon to pause to clear the lenses of condensation interfering with his or her vision. The necessity for clear vision during surgical procedures as well as the time expediency element has fostered a need for preventing such fogging.
One attempt to eliminate fogging has been the chemical treatment of optical lenses to reduce condensation to vapor thereon. Such attempts deal with the problem rather than eliminating it. The most economical and straightforward approach would be to prevent the moist air from the breath of the wearer of the optical aids from contacting them. Thus, some surgeons have resorted to the expediency of using strips of adhesive tape to seal the upper edge of the mask against their face. The tape by necessity adheres to the tender skin beneath the eyes. Since a surgeon may operate several times in one day, the tape may be removed numerous times causing severe chafing and irritation in this area. Aside from the chafing and inconvenience to the surgeon, this means poses possible problems with allergy to the tape in some persons, and even so-called "hypoallergenic" tapes can cause skin irritations. The serious import of the fogging effect for both the wearer and the patient has thus necessitated an effective method of and means for eliminating this problem.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a new and improved means for preventing the fogging of optical aids used by a wearer of a face mask.
Another object of the present invention is to provide a new and improved means for substantially reducing the amount of a wearer's breath which rises through a surgical face mask in the vicinity of the wearer's eyes.
It is a further object of the present invention to provide a new and improved means for sealing a surgical face mask against the wearer's face to prevent the rise of the wearer's breath in the vicinity of the wearer's eyes.
It is a further object of the present invention to provide a surgical face mask with a contouring seal along the upper edge thereof which substantially prevents the rising of the wearer's breath from beneath the face mask around the vicinity of the wearer's eyes.
A still further object of the present invention is to provide a simple, inexpensive device which may be incorporated in or attached to a surgical face mask to substantially eliminate the fogging of optical instruments or aids used by the wearer of the mask.
A new and improved means for preventing fogging of optical aids and instruments used by a person wearing a surgical mask, in accordance with the principles of the present invention, includes an elongated cushioning element for interpositioning between the upper mask edge and the wearer's face, a strip of pliable material secured along the upper edge of the mask of sufficient retentivity to retain its shape upon deformation and compress the cushioning element to form a seal, and a sheet of air impervious film covering a sufficient portion of the upper part of the mask to prevent fluid vapor in the wearer's breath from reaching the vicinity of the wearer'eyes.
The pliable strip may be similar to the kind utilized in the prior art which can be contoured to the wearer's face but having sufficient retentivity to retain that shape and hold the elongated cushioning element against the wearer's face with sufficient pressure to form an upper edge seal between the mask and the wearer's skin. The cushioning element may be contoured to provide better sealing characteristics and facilitate down-vision. The air impervious film covers a sufficient portion of the upper area of the mask to block the rise of the exhausted breath deflecting it away from the vicinity of the wearer's eyes. The film may be as wide as the length of the wearer's nose to provide an effective moisture barrier in the vicinity of the wearer's eyes.
The device may be incorporated as a part of the mask itself or an attachment thereto. By providing an adhesive backing on one side of the film, the device can be secured along the upper edge of most types of existing surgical masks. The invention thereby provides the advantages described herein for surgical face masks of both the disposable and nondisposable types. When used with those masks already embodying a pliable strip of sufficient retentivity along the upper edge, a device need comprise only the contoured foam layer and the air impervious sheet. Thus, only wearers needing optical aids such as glasses or surgical loupes need take advantage of the attachment or the modified face mask. The moisture barring and sealing characteristics are thus provided in a manner which facilitates maximum utilization of any desired mask and meets the needs of individual wearers.
DESCRIPTION OF THE DRAWINGS
The objects and various features of the present invention will be understood from the following detailed description thereof when read in conjunction with the accompanying drawings, wherein
FIG. 1 is a perspective view of a surgical face mask with a device for eliminating the fogging of optical aids operably affixed thereto;
FIG. 2 is a perspective view of the device embodying the principles of the present invention as shown affixed to a surgical mask in FIG. 1;
FIG. 3 is an enlarged, side elevational, cross-sectional view of the mask and the device attached thereto as shown in FIG. 1 and taken along the line 3--3 thereof;
FIG. 4 is the same view as FIG. 3 illustrating a different embodiment of the invention and of the mask; and
FIG. 5 is a perspective view of the mask and the device attached thereto, as shown in FIG. 1, positioned on a wearer's face outlined in phantom.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Attention is first directed to FIG. 1 wherein a surgical face mask 17 is shown having a rectangular shape and formed of high efficiency filter material of the disposable variety. The filter construction allows the inhalation and exhaustion of air therethrough while preventing the passage of airborne bacteria. The mask 17 may be of the laminated type including a soft inner liner of filter material and a durable, thin outer cover. It may be pleated or folded in the center to provide sufficient room for expanding around the wearer's nose and chin and to provide a sufficient surface area for substantially filtering all of the wearer'breath therethrough.
Attention is next directed to the upper portion of the mask 17 wherein a fog eliminating device 10 as most clearly shown in FIG. 2 is affixed and includes a pliable strip of material 11 bonded to an elongated cushioning strip 12, both sheathed by a sleeve 13 formed by and along an edge of a sheet of impervious film 14. A coating of adhesive material 15 is provided on the bottom surface of the film 14. A suitable, removable backing 9 is provided to protect the adhesive 15 prior to attachment to a mask 17.
As shown most clearly in FIGS. 2, 3, and 4, the device 10 is affixed by the adhesive 15 to an upper edge 16 of the mask 17. The sheet 14 may be positioned across the outside (FIG. 3) or inside (FIG. 4) upper surface of the mask 17. The sheet 14 is preferably folded along the edge 16 with the sheet 14 across the outside of the mask 17 as shown in FIG. 3. In this manner the sheathed strip 11 and cushion 12 extend along the inside top portion of the mask 17.
As shown in FIG. 5, the mask 17 is secured to wearer W in the usual fashion. Elongated ribbons or ties 19 and 20, form the side edges of the mask 17 (FIG. 1) and hold the mask 17 against the face of the wearer W. The upper edge ties 19 and 20 are fastened sufficiently tight to pull the pliable strip of material 11 in a select, contoured shape toward the wearer's face. The strip 11 in this contoured shape compresses the cushion 12 along its length and produces a seal between the upper edge 16 and the wearer's face.
As appears most clearly in FIG.'S 2 and 3, the pliable strip 11 and the cushion 12 are enclosed by the sleeve 13 of the impervious sheet 14. This preferred design allows the use of a porous, open celled foam material for the cushion 12. The sleeve 13 is not necessary if material for the cushion 12 is nonporous, such as closed cell foam, and can serve as a seal without the covering of the sheet 14. In either design, the sheet 14 extends substantially along the full length of the upper edge 16 of the mask 17 at a width of generally up to 1.5 inches, which is sufficient to form an effective moisture barrier by extending over the length of the wearer's nose (FIG. 5). Sheet 14 is thin, lightweight in construction and fabricated from inexpensive air impervious material, having a precoated adhesive backing. The essential characteristic of the sheet 14 is that it be an effective barrier to the transfer of moisture therethrough, and air impervious materials are the most effective in this application.
The cushion 12 has a generally rectangular cross-sectional shape and may be formed from a soft resilient foam of either an open or closed celled variety. Polyurethane foam is a suitable material having high compressibility to conform to the contours of the wearer's face. As shown in FIG. 2, the central portion of the cushion 12 has a curve or notch 22 formed therein and is thickest at the portions on the opposite sides of the curved portion 22 tapering down to thinner portions at the opposite edges 23--23. The amount of curvature is dependent upon the compressibility characteristic of the foam. The more compressible the foam the less preformed contour is required for conforming to the wearer's face and providing the necessary seal. The curve 22 of the cushion 12 accommodates the wearer's nose. The end portions 23--23 of the cushion 12 are of reduced thickness to increase the applied compressive force in the center of the mask 17 and facilitate the down-vision of the wearer in this area. The forces holding the mask 17 to the wearer's face are thus more uniformly distributed across the upper edge 16 of the mask 17 by providing this contour.
An effective contour is defined by relating cushion 12 thickness to its maximum thickness. In accordance with one specific example of the invention, a thickness variation of one-half maximum thickness near the curve 22 has proven to be suitable to accommodate the wearer's nose. A thickness variation of one-third maximum thickness at the ends 23--23 has proven to be effective to eliminate interference with the wearer's down-vision in this area. These variations relate to a maximum thickness of 0.375 inches in a cushion 12 formed of an open celled polyurethane foam. The contoured shape of cushion 12 thus accommodates the basic facial structure of the average wearer to enhance the individually conforming and sealing qualtities of the device 10.
The pliable strip 11 is affixed to the cushion 12 by any suitable means such as bonding thereto by a suitable adhesive. The pliable strip 11 comprises a malleable material such as aluminum. Such a soft metal is readily deformable and yet of sufficient retentivity to maintain the shape given it for the necessary compression of the cushion 12. Slight pressure applied by the wearer's fingers deforms strip 11 about the nose of the wearer conforming the device 10 to the wearer's individual cheek and nose bone contours. By securely fastening the mask 17 to the wearer's face by the ties 19 and 20, the contoured strip 11 then provides the necessary compressive force to cushion 12 forming the desired seal.
As appears most clearly in FIG. 4, device 10 may be adapted for attachment to surgical masks 17 already having a pliable strip fabricated therein. The pliable strip is usually located on the outside surface of such a mask as shown. A variety of such masks 17 are available but the pliable strip is often not of sufficient length or retentivity to provide a suitable contour for use in place of strip 11. A suitable pliable strip is one which retains the contoured shape given it while being tightly pulled against the face of the wearer. The strip 11 will preferably extend substantially the length of the edge 16. For a mask 17 already formed with a suitable pliable strip, device 10 is formed without the strip 11 and is otherwise the same in construction and application. As stated above, the position of the sheet 14 in FIG. 4, across the inside of the mask 17 is an illustration of an alternative method of attaching the device 10.
As shown in FIG. 5, the fogging of an optical aid 25 used by the wearer W of a surgical mask 17 may be prevented by the device 10 described above, which can most economically be utilized by integrating or incorporating it in the mask 17 itself. In this manner the elements of the device 10 can be formed between or upon the layers of the upper portion of the mask 17. For example, the strip 11 and the sheet 14 can be effectively positioned within the upper portion of mask 17. The cushion 12 could then be suitably affixed along the edge 16, contiguous to the strip 11, by any conventional means.
The method of preventing fogging of optical aids 25 used by the wearer W of a surgical mask 17 by the device 10 is shown in FIG. 5. The sheet 14 in conjunction with cushion 12 forms a sealed barrier to both the air and the moisture, which barrier extends downwardly on the face mask 17 sufficiently to shield the necessary vicinity of the wearer's eyes. Warm breath would otherwise pass through the porous upper portion of the mask 17 as well as around the edge 16 thereof into the vicinity of the optical aid 25.
Further facilitating the effectiveness of the barrier to moisture exhausted in the area of the optical aid 25, is the seal formed between the cushion 12 and the face of the wearer W. The sleeve 13 around the cushion 12 effectively blocks any air that could pass therethrough. This design also positions the air impervious material against the skin. Furthermore, the skin of the wearer beneath the cushion 12 may be induced to perspire forming a narrow layer of moisture between the sheet 14 and the wearer's skin. This, however, serves to increase the effectiveness of the barrier by providing an additional seal in the form of a moisture layer which can absorb or block the rise of moisture vapor from the wearer's breath.
The above-described device is both comfortable for the wearer W and effective in preventing the fogging of optical aids. The device 10 may be supplied with or without the surgical mask 17. It is sufficiently durable for prolonged use, yet can be economically disposed of after a single application.
The operation and construction of the above-described invention will be apparent from foregoing description. While the particular embodiment shown and described has been characterized as being preferred, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims. | A surgical mask is provided with means for preventing fogging of optical aids used by the wearer. The means comprises a strip of pliable material bonded to a layer of soft foam interposed between the upper edge of the mask and the wearer's face. An air impervious film sheathes the layer of foam and extends laterally therefrom a sufficient distance to cover an upper portion of the mask in the area below the wearer's eyes. The interposed material shapes itself and sufficiently extends over the wearer's face to form a seal and a moisture barrier preventing fluid vapor in the wearer's breath from contacting eye glasses or other optical instruments worn by the wearer and susceptible to fogging. | 0 |
RELATED APPLICATIONS AND INCORPORATION BY REFERENCE
This application claims benefit of European patent application Serial No. 12164775.4 filed 19 Apr. 2012.
The foregoing applications, and all documents cited therein or during their prosecution (“appln cited documents”) and all documents cited or referenced in the appln cited documents, and all documents cited or referenced herein (“herein cited documents”), and all documents cited or referenced in herein cited documents, together with any manufacturer's instructions, descriptions, product specifications, and product sheets for any products mentioned herein or in any document incorporated by reference herein, are hereby incorporated herein by reference, and may be employed in the practice of the invention. More specifically, all referenced documents are incorporated by reference to the same extent as if each individual document was specifically and individually indicated to be incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to Brassica plants, in particular Brassica oleracea plants resistant to Thrips tabaci , to seeds and progeny from the seeds and plants, and to a method for producing such a plant.
BACKGROUND OF THE INVENTION
The present invention relates to Brassica plants, in particular Brassica oleracea plants which are resistant to Thrips tabaci and herein display agronomically desirable traits.
Thrips tabaci (also known as Onion thrips, or simply thrips) is a highly polyphagous insect and considered as an economically harmful pest for many cultivated crops especially for crops from the Liliaceae, Solanaceae, and Brassicaceae plant families, such as onion, leek, tomato, cabbage, but also in crops from outside these families, such as e.g. cucumber, melon and snap beans (Toda & Murai, 2007, Applied Entomology and Zoology 42: 309-316; Trdan et al., 2005, African Entomology 13: 85-95).
Thrips harm the plant directly by feeding on the plant tissue and indirectly by being a vector for lethal plant viruses such as tomato spotted wild virus (Toda & Murai, 2007, Applied Entomology and Zoology 42: 309-316). Thrips occur worldwide and due to climate change and trade the frequency of thrips infestation is increasing (Trdan et al., 2005; African Entomology 13: 85-95).
Cabbage plants ( Brassica oleracea var. capitata L.) belong to the plant family Brassicaceae. The family has a cosmopolitan distribution and consists of approximately 3500 to 4000 species. The family and especially the genus Brassica contains many agronomically important crops such as broccoli, Brussels sprouts, cauliflower, Chinese cabbage, curly cabbage, kale, kohlrabi, mustard, oxheart cabbage, radish, rapeseed, red cabbage, Savoy cabbage, turnip, and white cabbage.
In tissue of Brassica oleracea var. capitata plants affected by thrips callus growths will form. Over time these callus growths become brown making it necessary to remove several layers of leaves from the cabbage head before marketing. Even in storage the development of symptoms caused by thrips may increase. The reduction in head size and weight ultimately leads to a loss in yield. For Brassica oleracea var. capitata it is estimated that 75% of its total acreage suffers from thrips.
Controlling thrips in cabbage by means of applying insecticide is considered environmentally unfriendly and ineffective, because the closed leaves of the cabbage heads provide protection to the thrips, and because thrips are hard to detect, sometimes even only at harvest stage. Thrips infestation in cabbages may occur from the second exterior leaf up to the fifteenth exterior leaf, while insecticides are usually only effective up to the sixth exterior leaf of the head (Trdan et al., 2005; African Entomology 13: 85-95). Therefore, there is an urgent need for cabbage plants which are resistant against this pest.
Although no highly thrips resistant Brassica oleraceae varieties are known, huge differences in susceptibility exist among varieties. Certain varieties show an intermediate level of resistance, but no varieties are known that are highly resistant against Thrips tabaci . The genetic background of this intermediate resistance against thrips is still poorly understood and it is thought that this is a polygenic trait, inherited as a gene complex in which many genes are involved (Voorrips et al., 2008; Euphytica 163: 409-415).
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.
SUMMARY OF THE INVENTION
Because in the present state of the art no highly thrips resistant cabbage varieties are known, it is the object of the present invention to provide a Brassica plants, in particular Brassica oleracea plant with a high resistance to Thrips tabaci.
In the research that led to the present invention novel Brassica oleracea plants were developed that are highly resistant against thrips.
The said resistance of the invention is controlled by a genetic determinant, the inheritance of which is consistent with that of a monogenic additive trait. ‘Additive trait’ in this case means that the fully achievable resistance is only observable in plants which may comprise the genetic determinant in homozygous state, however plants which may comprise the genetic determinant in heterozygous state will show an intermediate level of resistance.
Since the inheritance of the resistance is comparable to that of a monogenic trait, it has a second advantage over the prior art, because the resistance level is not only higher but also easier to incorporate in new Brassica varieties as compared to the complex polygenic traits from the prior art which led to plants with only an intermediate resistance against thrips.
Accordingly, it is an object of the invention to not encompass within the invention any previously known product, process of making the product, or method of using the product such that Applicants reserve the right and hereby disclose a disclaimer of any previously known product, process, or method. It is further noted that the invention does not intend to encompass within the scope of the invention any product, process, or making of the product or method of using the product, which does not meet the written description and enablement requirements of the USPTO (35 U.S.C. §112, first paragraph) or the EPO (Article 83 of the EPC), such that Applicants reserve the right and hereby disclose a disclaimer of any previously described product, process of making the product, or method of using the product.
It is noted that in this disclosure and particularly in the claims and/or paragraphs, terms such as “comprises”, “comprised”, “comprising” and the like can have the meaning attributed to it in U.S. patent law; e.g., they can mean “includes”, “included”, “including”, and the like; and that terms such as “consisting essentially of” and “consists essentially of” have the meaning ascribed to them in U.S. patent law, e.g., they allow for elements not explicitly recited, but exclude elements that are found in the prior art or that affect a basic or novel characteristic of the invention.
These and other embodiments are disclosed or are obvious from and encompassed by, the following Detailed Description.
DEPOSITS
Seeds of Brassica oleracea plants resistant to Thrips tabaci were deposited under NCIMB deposit accession number 41760 on 29 Sep. 2010 with NCIMB Ltd. (Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen, AB21 9YA). All seeds of the deposit comprise the genetic determinant homozygously. Plants grown from these seeds are thus highly resistant against Thrips tabaci.
The Deposits with NCIMB Ltd, Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen AB21 9YA, UK, under deposit accession number 41760 were made pursuant to the terms of the Budapest Treaty. Upon issuance of a patent, all restrictions upon the deposit will be removed, and the deposit is intended to meet the requirements of 37 CFR §§1.801-1.809. The deposit will be irrevocably and without restriction or condition released to the public upon the issuance of a patent and for the enforceable life of the patent. The deposit will be maintained in the depository for a period of 30 years, or 5 years after the last request, or for the effective life of the patent, whichever is longer, and will be replaced if necessary during that period.
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description, given by way of example, but not intended to limit the invention solely to the specific embodiments described, may best be understood in conjunction with the accompanying drawings.
FIG. 1 . Schematic overview of a part of chromosome two indicating markers (in bold) that may be linked to the genetic determinant conferring thrips resistance (SEQ ID NO 1, 2, 3, and 5) together with flanking markers (SEQ ID NO: 4, 6, and 7). On the left side the genetic distance indicated in centiMorgans. On the right side, the markers are indicated.
DETAILED DESCRIPTION OF THE INVENTION
The present invention thus relates to a Brassica plant, in particular a Brassica oleracea plant, which may comprise a genetic determinant, which when homozygously present confers high resistance against Thrips tabaci , and which is as found in plants grown from seeds of which a representative sample is deposited with the NCIMB under NCIMB accession number 41760.
The present invention also relates to a Brassica plant, in particular a Brassica oleracea plant, which may comprise the genetic determinant heterozygously, and thus showing intermediate resistance against Thrips tabaci , and which genetic determinant is obtainable from plants grown from seeds of which a representative sample is deposited with the NCIMB under NCIMB accession number 41760.
The invention furthermore relates to a Brassica plant which may comprise the genetic determinant homozygously, and therefore is highly resistant against Thrips tabaci.
In one embodiment the invention provides a Brassica plant, in particular a Brassica oleracea plant, that is resistant to Thrips tabaci , obtainable by crossing a resistant plant of which representative seed was deposited under NCIMB number 41760 with another cabbage plant to produce an F1 and subsequently selfing the F1 to obtain an F2 and selecting a plant therefrom that shows resistance to Thrips tabaci.
Furthermore, it was found during the research leading to the present invention that the genetic determinant conferring resistance to Thrips tabaci , is located on chromosome 2 and linked to marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or BO00602 (SEQ ID NO: 5).
More in particular, in the deposit NCIMB 41760 the genetic determinant conferring resistance to Thrips tabaci , is located on chromosome 2 between marker BO00458 (SEQ ID NO: 7) and marker BO01225 (SEQ ID NO: 6) and linked to marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or marker BO00602 (SEQ ID NO: 5).
Most in particular the genetic determinant conferring resistance to Thrips tabaci , is located on chromosome 2 between marker BO01146 (SEQ ID NO: 3) and marker BO00310 (SEQ ID NO: 4) and linked to marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) in seeds deposited under NCIMB accession number 41760, see also FIG. 1 .
Alternatively the genetic determinant conferring resistance to Thrips tabaci , is located on chromosome 2 between markers BO00310 (SEQ ID NO: 4) and BO00458 (SEQ ID NO: 7) and linked to BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or marker BO01146 (SEQ ID NO: 3) and/or marker BO00602 (SEQ ID NO: 5), in particular between marker BO00458 (SEQ ID NO: 7) and marker BO01146 (SEQ ID NO: 3) and linked to marker BO00602 (SEQ ID NO: 5).
Therefore, the invention also relates to a Brassica plant resistant to Thrips tabaci , which may comprise a genetic determinant that confers resistance to Thrips tabaci , wherein said genetic determinant is obtainable by introgression from a plant grown from seeds of which a representative sample was deposited with the NCIMB under NCIMB accession number 41760, and wherein the said genetic determinant in the seeds of the seed deposit number NCIMB 41760 is positioned on chromosome 2 and linked to marker BO00200 (SEQ ID NO: 1), and/or BO00277 (SEQ ID NO: 2), and/or marker BO00602 (SEQ ID NO: 5).
A Brassica plant carrying the genetic determinant conferring resistance against thrips may suitably be identified among descendants from a cross between a plant susceptible for thrips, and a plant that does carry the genetic determinant in homozygous state, by growing F2 plants from seeds that are the result from the initial cross and a selfing step, and selecting plants showing the desired trait. Selecting the plants may be done phenotypically, or may be done through identification of the genetic determinant, for example by means of one or more of the markers defined herein.
In the absence of molecular markers or in the event that recombination between the molecular markers and the genetic determinant have taken place and thus are not predictive anymore, equivalence of genetic determinants may still be determined by an allelism test. To perform an allelism test, material that is homozygous for the known determinant, a tester plant, is crossed with material that is homozygous for the genetic determinant that is to be tested. This latter plant is referred to as the donor plant. The donor plant to be tested should be or should be made homozygous for the genetic determinant to be tested. The skilled person knows how to obtain a plant that is homozygous for the genetic determinant to be tested. When in the F2 of the cross between a donor plant and a tester plant no segregation for the phenotype related to the genetic determinant is observed, the genetic determinants of the donor plant and the tester plant have been proven to be equivalent or the same.
The invention also relates to a Brassica plant that may comprise a genetic determinant conferring resistance to Thrips tabaci , wherein plants of first generation progeny (F1) of a cross of the said plant with a tester plant, that may comprise the said genetic determinant and of which representative seed was deposited with the NCIMB under accession number NCIMB 41760, or a progeny plant thereof that may comprise the said genetic determinant, or a plant derived therefrom and which may comprise the said genetic determinant, show a 1:0 segregation for the resistance against Thrips tabaci . In both the tester plant and the plant of the invention the genetic determinant is present in homozygous form. Plants of the second and further generations, if obtained by selfing also show a 1:0 segregation for the said resistance pattern. The tester plant may be a plant of which representative seed was deposited with the NCIMB under accession number NCIMB 41760.
The Brassica plant of the invention is preferably a Brassica oleracea plant, but may also be any other plant of the genus Brassica into which the skilled person may introgress the genetic determinant of the invention, e.g. the following Brassica species: Brassica oleracea, Brassica napus, Brassie campestris, Brassica cretica, Brassica rapa, Brassica juncea , and Brassica nigra . The skilled person knows how to make interspecific crosses with these species, e.g. by means of embryo rescue, protoplast fusion, and other related technologies.
In another embodiment the invention relates to seeds which may comprise the said genetic determinant conferring resistance against Thrips tabaci . A plant grown from the seeds is highly resistant to thrips when the genetic determinant is present in homozygous state.
The invention thus further relates to seeds which may comprise said genetic determinant and which seeds are capable of growing into plants that are highly resistant against Thrips tabaci.
According to a further aspect thereof, the invention relates to propagation material capable of growing into a plant of the invention.
In one embodiment, such propagation material is formed by seed of a Brassica plant of the invention, wherein the plant that may be grown from the seed may comprise a genetic determinant of the invention.
In another embodiment the propagation material capable of growing into a plant of the invention is selected from the group consisting of microspores, pollen, ovaries, ovules, embryos, embryo sacs, egg cells, cuttings, roots, root tips, hypocotyls, cotyledons, stems, leaves, flowers, anthers, seeds, meristematic cells, protoplasts, and cells.
In a further embodiment the invention relates to tissue culture of propagation material capable of growing into a plant of the invention.
Suitably, the plant produced from the propagation material may comprise the genetic determinant as found in Brassica plants grown from seeds of seed lot AG6359-35/39, a representative sample of which was deposited with the NCIMB under NCIMB accession number 41760. When the genetic determinant is present in homozygous state the plant produced shows high resistance to Thrips tabaci , in particular the resistance as observed in Brassica plants grown from seeds of seed lot AG6359-35/39, a representative of which was deposited with the NCIMB under NCIMB accession number 41760. When the genetic determinant is present in heterozygous state the plant shows intermediate resistance.
The invention also relates to progeny of the plants, cells, tissues and seeds of the invention. Such progeny may in itself be plants, cells, tissues or seeds.
As used herein the word “progeny” is intended to mean the first and all further descendants from a cross with a plant of the invention that may comprise the said genetic determinant. “Progeny” also encompasses plants that carry the trait of the invention and are obtained from other plants or progeny of plants of the invention by vegetative propagation or multiplication.
Therefore, in one embodiment the invention relates to progeny of a Brassica plant which may comprise the genetic determinant of the invention.
In a further embodiment the invention relates to progeny of Brassica plants of the invention that are resistant against Thrips tabaci . These progeny plants thus may comprise the genetic determinant conferring resistance against thrips.
In one aspect the invention relates to the harvested part of a Brassica plant which may comprise the genetic determinant conferring thrips resistance.
The invention furthermore relates to a food product which may comprise one or more harvested parts of a Brassica plant which may comprise the genetic determinant conferring thrips resistance.
The harvested part or food product may be or may comprise a cabbage head, a curd, a stem, a leaf, a root, a sprout, a seed, or any other part of a Brassica plant. The harvested part may also be used for the production of bio-fuel. The food product or harvested part, may have undergone one or more processing steps. Such a processing step might comprise but is not limited to any one of the following treatments or combinations thereof: cutting, washing, cooking, steaming, baking, frying, pasteurizing, freezing, grinding, extracting oil, pickling, or fermenting. The processed form that is obtained is also part of this invention.
Another aspect of this invention relates to a nucleic acid molecule which is causative of resistance against Thrips tabaci . The said DNA molecule may comprise a DNA sequence which is positioned on chromosome 2 between markers BO00458 (SEQ ID NO: 7) and BO01225 (SEQ ID NO: 6), more in particular between markers BO00458 (SEQ ID NO: 7) and BO00146 (SEQ ID NO: 3), or between markers BO00146 (SEQ ID NO: 3) and BO00310 (SEQ ID NO: 4), or a part thereof.
Yet another aspect of the invention relates to use of the markers and said nucleic acid molecule to identify plants which are resistant against Thrips tabaci , and/or carry the genetic determinant conferring resistance to Thrips tabaci.
Therefore, in one embodiment the invention relates to the use of marker BO00200 (SEQ ID NO: 1), or marker BO00277 (SEQ ID NO: 2), or marker BO00602 (SEQ ID NO: 5), or the said DNA molecule which may comprise a DNA sequence which is positioned on chromosome 2 between markers BO00458 (SEQ ID NO: 7) and BO01225 (SEQ ID NO: 6), or BO00146 (SEQ ID NO: 3) and BO00310 (SEQ ID NO: 4), or BO00458 (SEQ ID NO: 7) and BO00146 (SEQ ID NO: 3), or part thereof, to identify plants resistant against Thrips tabaci , and/or carrying the genetic determinant conferring resistance to Thrips tabaci.
The skilled person knows how to develop new markers linked to a trait using already known markers, QTLs, alleles, genes or other DNA molecules that are associated with a certain trait.
Thus, the invention also relates to the use of markers BO00200 (SEQ ID NO: 1), BO00277 (SEQ ID NO: 2), and BO00602 (SEQ ID NO: 5), and the said DNA molecule, or part thereof, for developing other markers linked to the genetic determinant conferring thrips resistance.
In one embodiment, the genetic determinant conferring resistance to Thrips tabaci also confers resistance against other sap sucking insect species, wherein the sap sucking insect species is selected from, but not limited to the group consisting of Aleyrodes proletella, Myzus persicae , and Brevicoryne brassicae.
In one aspect the invention relates to a process for producing Brassica plants which may comprise a genetic determinant that confers resistance to Thrips tabaci , which may comprise the step of selecting said Brassica plants from a population of Brassica plants segregating for the said genetic determinant using marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or BO00602 (SEQ ID NO: 5).
The term ‘genetic determinant’ as used herein encompasses one or more QTLs, genes, or alleles. These terms are used interchangeably. A genetic determinant may be identified by the use of a molecular marker. A genetic determinant may alternatively be identified by the position on a genetic map, or by indication of the location on a linkage group or chromosome. When a genetic determinant is not linked to a specific molecular marker any longer, but its position on a chromosome as defined on a genetic map is unaltered, this genetic determinant is still the same as when it was linked to the molecular marker. The genetic trait that it confers is therefore also still the same. The ‘genetic trait’ is the trait or characteristic that is conferred by the genetic determinant. The genetic trait may be identified phenotypically, for example by performing a bio-assay. However, also plant stages for which no phenotypic assay may be performed do carry the genetic information that leads to the genetic trait. ‘Trait’ or ‘phenotypic trait’ may be used instead of ‘genetic trait’.
In one embodiment, the invention relates to Brassica plants of the invention that carry the genetic determinant conferring resistance to Thrips tabaci , and having acquired said determinant by introduction of the genetic information that is responsible for the trait from a suitable source, either by conventional breeding, or genetic modification, in particular by cisgenesis or transgenesis. Cisgenesis is genetic modification of plants with a natural gene, coding for an (agricultural) trait, from the crop plant itself or from a sexually compatible donor plant. Transgenesis is genetic modification of a plant with a gene from a noncrossable species or a synthetic gene.
The invention also relates to the germplasm of plants of the invention. The germplasm is constituted by all inherited characteristics of an organism and according to the invention encompasses at least the genetic determinant of the invention. The germplasm may be used in a breeding program for the development of thrips resistant Brassica plants.
In one aspect the invention relates to a method for production of a Brassica plant is resistant against Thrips tabaci , which may comprise:
a) crossing a plant which may comprise a genetic determinant that leads to resistance against Thrips tabaci with another plant; b) selfing the resulting F1 for obtaining F2 plants; c) selecting plants resistant to Thrips tabaci in the F2; d) optionally performing one or more additional rounds of selfing or crossing, and subsequently selecting, for a plant which may comprise said resistance against Thrips tabaci.
It is clear that the parent that provides the trait of the invention is not necessarily a plant grown directly from the deposited seeds. The parent may also be a progeny plant from the seed or a progeny plant from seeds that are identified to have the trait of the invention by other means.
In one aspect, the invention relates to a method for production of a Brassica plant resistant against Thrips tabaci , which may comprise:
a) crossing a plant which may comprise the genetic determinant that leads to resistance against Thrips tabaci with another plant; b) optionally backcrossing the resulting F1 with the preferred parent; c) selecting for plants resistant to Thrips tabaci in the F2; d) optionally performing one or more additional rounds of selfing or crossing, and subsequently selecting, for a plant which may comprise the said resistance is performed.
The invention additionally provides a method of introducing a desired trait into a Brassica plant resistant against Thrips tabaci , which may comprise:
a) crossing a Brassica plant resistant to Thrips tabaci , representative seed of which were deposited with the NCIMB under deposit number NCIMB 41760, with a second Brassica plant that may comprise a desired trait to produce F1 progeny; b) selecting an F1 progeny that may comprise said resistance and the desired trait; c) crossing the selected F1 progeny with either parent, to produce backcross progeny; d) selecting backcross progeny which may comprise the desired trait and resistance against Thrips tabaci ; and e) optionally repeating steps c) and d) one or more times in succession to produce selected fourth or higher backcross progeny that may comprise the desired trait and resistance against Thrips tabaci . The invention includes a Brassica plant produced by this method.
In one embodiment selection for plants resistant against Thrips tabaci is done in the F1 by using marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or BO00602 (SEQ ID NO: 5). In another aspect selection for the trait of the invention is started in the F2 of a cross or alternatively of a backcross. Selection of plants in the F2 can be done phenotypically as well as by using the said markers.
In one embodiment selection for plants resistant against Thrips tabaci is started in the F3 or a later generation.
In one embodiment the plant which may comprise the genetic determinant is a plant of an inbred line, a hybrid, a doubled haploid, or of a segregating population.
The invention further provides a method for the production of a Brassica plant resistant against Thrips tabaci by using a doubled haploid generation technique to generate a doubled haploid line which may comprise the said resistance.
The invention furthermore relates to hybrid seed that may be grown into a thrips resistant plant and to a method for producing such hybrid seed which may comprise crossing a first parent plant with a second parent plant and harvesting the resultant hybrid seed, wherein said first parent plant and/or said second parent plant is the plant as claimed.
In one embodiment, the invention relates to a method for producing a hybrid Brassica plant that is resistant to thrips, which may comprise crossing a first parent Brassica plant with a second parent Brassica plant and harvesting the resultant hybrid seed, of which the first parent plant and/or the second parent plant is resistant against Thrips tabaci , and growing said hybrid seeds into thrips resistant hybrid plants.
The invention also relates to a method for the production of a Brassica plant resistant against Thrips tabaci by using a seed that may comprise a genetic determinant in its genome that leads to resistance against Thrips tabaci for growing the said Brassica plant. The seeds are suitably seeds of which a representative sample was deposited with the NCIMB under deposit number NCIMB 41760.
The invention also relates to a method for seed production which may comprise growing Brassica plants from seeds of which a representative sample was deposited with the NCIMB under deposit number NCIMB 41760, allowing the plants to produce seeds, and harvesting those seeds. Production of the seeds is suitably done by crossing or selfing.
In one embodiment, the invention relates to a method for the production of a Brassica plant resistant against Thrips tabaci by using tissue culture.
The invention furthermore relates to a method for the production of a Brassica plant resistant against Thrips tabaci by using vegetative reproduction.
In one embodiment, the invention relates to a method for the production of a Brassica plant resistant against Thrips tabaci by using a method for genetic modification to introgress the said resistance into the Brassica plant. Genetic modification may comprise transgenic modification or transgenesis, using a gene from a non-crossable species or a synthetic gene, and cisgenic modification or cisgenesis, using a natural gene, coding for an (agricultural) trait, from the crop plant itself or from a sexually compatible donor plant.
The invention also relates to a breeding method for the development of Brassica plants that are resistant against Thrips tabaci wherein germplasm which may comprise said resistance is used. Representative seed of said plant which may comprise the genetic determinant and being representative for the germplasm was deposited with the NCIMB under deposit number NCIMB 41760.
In a further embodiment the invention relates to a method for the production of a Brassica plant resistant against Thrips tabaci wherein progeny or propagation material of a plant which may comprise the genetic determinant conferring said resistance is used as a source to introgress the said resistance into another Brassica plant. Representative seed of said plant which may comprise the genetic determinant was deposited with the NCIMB under deposit number NCIMB 41760.
The invention provides preferably a Brassica plant resistant to Thrips tabaci , which plant is obtainable by any of the methods herein described and/or familiar to the skilled person.
SEQUENCE DATA
TABLE 1
Sequence data of the SNP markers of FIG. 1. In NCIMB
deposit 41760 the markers BO00200, BO00277,
and BO00602 are linked to the genetic
determinant conferring resistance against Thrips.
BO00200
TTGTCCGGAAAATAAGCCCTTCCTTCTCCATGAGCCGCCCAA
SEQ ID NO: 1
ACTCCTAAAGTACTTACC[T/C]TCCATTCCTTTCAGCACTATTG
ACGGACAGTCCTTGATGGTCACGCTTGTGAACCTGCAG
BO00277
GCTTGTCCAGCTTATGAGCATTTTGTAATACATGTTTGCTTGG
SEQ ID NO: 2
ATGGTCAAACCTGAAAA[A/C]ACACACAAGTTCAACAATTCT
CAGAAGATGGATAAACCTGCAG
BO01146
TTAAAAACAAATNATGTTTTGTTTTACCTGCTTTTTCCTCTTCT
SEQ ID NO: 3
CGCTNNTTGNCAGCTTCTTCTCTCTGTTGGCGAATCAGAGCCA
AACGATCTGTACACAAACACACACAAGGGATAAGATAATCA
A[A/*]TAGGCTCATCTGGTAACAAAGAAAGAGAACAAGAGGT
CCATTGTTTTTTTACNNAANTCCTTNNTTGNTTGCTCGGTTTT
NNCNTGNNNCTGCAACCTCATGTATCGCTCATGAGCTCGTTG
CTTCTCTAGCTCCTCCCTGCAG
BO00310
CATGTCATCTTTCGTNAGGTTTGTTATTTCTATGCCTCGTTTG
SEQ ID NO: 4
AGAGCTTCCCTCAATGG[A/C]CCCATAGTTGCATCTTTCACTA
GGTTCTTCATGTCTGATCCCGAGTACCCTGCAG
BO00602
TTAAATATGTGAATGCTGAAATRTTTGTTTAGCAGA[C/G]GAG
SEQ ID NO: 5
ACACAGGAAGAAGATCATCTCATGTTGTTCGCTCTCTCAGCA
GAGAGTTTGAAGTTGCAAGTACTCCTGCAG
BO01225
CCCTGTTWAAGGAGCCTCCTTGGAGCTTGTTGATACCTCAAA
SEQ ID NO: 6
GTTAGGTAGTGACAATGTGGATAATGAAAGTTTGAAGCTT
T[A/C]TCAACAATTAGCTGATAAGAGAGGTTCTTGTGAAGAGGA
TTTGATGAGAATCTCTATGAAGAAACGAGGTGTAATCAGCAA
TGTCTCCACCTCTYTGATGGAARATGCTRGTTTYGATGGAAT
ATTGGCTTCTCCTGCAG
BO00458
TAAAGAACCTGATGAAGAAAGTGAAGAGCTAGGTGGAAACC
SEQ ID NO: 6
TACTTGACCTGCTCCTAAG[T/G]TTCTTCACTTCCGGGATCTTC
TCCTCTTTTGATCTCACCTGCCTCACCTTTGCCTCGTTC
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 in the appended claims.
The present invention will be further illustrated in the following Examples which are given for illustration purposes only and are not intended to limit the invention in any way.
EXAMPLES
Example 1
Thrips resistant plants of the invention were compared with susceptible plants and plants with an intermediate resistance in an open field trial. Plants were naturally infected by using an attractant species. In this trial leek plants were used as a natural attractant for thrips. For the skilled person it is known that also other plants can be used as an attractant for Thrips tabaci , such as onion or shallots.
Plants from variety Rinda and Hurricane were used in this trial as susceptible control plants. Plants from varieties Langendijker Bewaar, Tacoma, and Multima were included in this trial since they are known to be intermediately resistant against Thrips tabaci . As highly resistant plants of the invention, plants grown from seeds of seed lot AG6359-35/39 of which a representative sample was deposited with the NCIMB under NCIMB accession number 41760, as well as plants of three lines derived from plants grown from seed of the seed deposit that were selfed, were used. These lines are AG2971, AG2973, and AG3086.
Each plant was scored for the amount of thrips infestation, based on the scale explained in Table 2. Symptoms were scored when the cabbage heads were mature. The skilled person is not bound to using this scale but can also use a scale with another subdivision of categories as long as the scoring will be done at the same stage, i.e. when the cabbage head is mature. This is not of influence on the final result of the screening.
TABLE 2
Scoring of thrips infestation.
Score
Symptoms
1
No symptoms/no damage
High
resistance
2
Occasional small symptoms on outer leaves
3
Minor damage. Max. 20% of head's surface is
Intermediate
covered by symptoms, only outer leaves are
resistance
infected.
4
Medium damage. Max. 50% of the head's surface
(all leaves accumulated) is covered by symptoms.
The symptoms are max. in the second and third
layer.
5
Heavy damage. More than 50% of the head's
Susceptible
surface (all leaves accumulated) is covered by
symptoms. Damage also observed in deeper leaf
layers
In Table 3 the scores of the trial are summarized. It is clear that all plants of the invention display a significantly higher resistance against thrips.
In field trials with a high disease pressure, even highly resistant plants show occasional symptoms of thrips infection. This can e.g. be the case when attractant plant species are used. In order to make a fair comparison between different trials using natural infection the same comparison varieties should be used, because the relative differences in damage observed by thrips infestation will approximately be the same while the mean scores of same plants in different trials can deviate substantially.
TABLE 3
Score of thrips resistance field trial.
Number of plants
Material
screened
Mean score
AG6359-35/39
17
1
Resistant
(NCIMB 41760)
AG2971
14
1.1
Resistant
AG2973
16
1.2
Resistant
AG3086
4
1.2
Resistant
Langendijker
22
3.1
Intermediate
Bewaar
Tacoma
6
3
Intermediate
Multima
6
3
Intermediate
Hurricane
10
4.4
Susceptible
Rinda
10
5
Susceptible
Example 2
Transfer of Thrips Resistance to Susceptible Plants
A thrips resistant plants of the invention AG 2973-35 (see Table 2 for resistance scores), was crossed with a susceptible plant FM 2979-01. Plants of the F1 were observed in a field trial as described in Example 1. No highly thrips resistant plants were observed.
From the F1 population a plant was selected which was selfed to obtain a population of F2 plants. The F2 was placed in a field trial as described in Example 1. Resistance scores are summarized in Table 4.
The segregation of the F2 population demonstrates that the inheritance of the resistance of the invention is comparable with that of a monogenic additive trait (highly resistant: intermediate resistant: susceptible=1:2:1). Depending on the genetic background of the susceptible parent plant there can be a different distribution between intermediately resistant and susceptible plants observed in the F2.
TABLE 4
Resistant
Intermediately
Susceptible
F2 population
plants
resistant plants
plants
Chi-square
F2(AG 2973-35 ×
24
59
32
1.24
FM 2979-01)
The invention is further described by the following numbered paragraphs:
1. A Brassica plant in particular a Brassica oleracea plant comprising a genetic determinant, which when homozygously present confers high resistance against Thrips tabaci , and which is as found in plants grown from seeds of which a representative sample is deposited with the NCIMB under NCIMB accession number 41760.
2. A Brassica plant of paragraph 1, which is homozygous for the genetic determinant and resistant against Thrips tabaci.
3. The Brassica plant of paragraph 1 or paragraph 2, wherein the said genetic determinant in the seeds of NCIMB deposit 41760 is located on chromosome 2 and linked to marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or marker BO00602 (SEQ ID NO: 5).
4. Seed comprising the genetic determinant as defined in any one of the paragraphs 1 to 3.
5. Seed of paragraph 4, wherein the plant that can be grown from the seed is resistant to Thrips tabaci.
6. Progeny of a Brassica plant of anyone of the paragraphs 1 to 3 or progeny of plants grown from seeds of paragraph 4 or paragraph 5, wherein the plant comprises the genetic determinant as defined in any one of the paragraphs 1-3.
7. Progeny plant of paragraph 6 wherein the progeny plant is resistant against Thrips tabaci.
8. Propagation material derived from a plant of any one of the paragraphs 1 to 3, wherein the propagation material comprises the genetic determinant as defined in any one of the paragraph 1 to 3.
9. Propagation material capable of growing into a plant as claimed in any one of the paragraphs 1 to 3.
10. Propagation material of paragraph 8 or paragraph 9, wherein the propagation material is selected from the group consisting of microspores, pollen, ovaries, ovules, embryos, embryo sacs, egg cells, cuttings, roots, root tips, hypocotyls, cotyledons, stems, leaves, flowers, anthers, seeds, meristematic cells, protoplasts, and cells.
11. Tissue culture of propagation material of any one of the paragraphs 8 to 10.
12. Harvested part of a Brassica plant of any one of the paragraphs 1-3, 6 or 7, which harvested part is in particular selected from the group consisting of cabbage head, curd, stem, leaf, sprout, root and seed, optionally in processed form.
13. Harvested part of paragraph 12, wherein the harvested part is a food product.
14. A nucleic acid molecule causative of resistance against Thrips tabaci , comprising a DNA sequence, which is linked to marker BO00200 (SEQ ID NO: 1) and/or marker BO00277 (SEQ ID NO: 2) and/or BO00602 (SEQ ID NO: 5) located on chromosome 2, in particular located on chromosome 2 between marker BO00458 (SEQ ID NO: 7) and marker BO01225 (SEQ ID NO: 6), or a resistance conferring part of said nucleic acid molecule.
15. Use of the markers as defined in paragraph 3, and/or use of the nucleic acid molecule of paragraph 14, to identify or develop Thrips tabaci resistant plants, or develop other markers linked to the genetic determinant as defined in anyone of the paragraphs 1 to 3.
16. Use of the markers of paragraph 2, or use of the nucleic acid molecule of paragraph 13, to develop other markers linked to the genetic determinant as defined in paragraph 2.
Having thus described in detail preferred embodiments of the present invention, it is to be understood that the invention defined by the above paragraphs is not to be limited to particular details set forth in the above description as many apparent variations thereof are possible without departing from the spirit or scope of the present invention. | The present invention relates to a tomato plant ( Solanum lycopersicum L.) which may comprise a genetic determinant that confers resistance to Pepino Mosaic Virus (PepMV), wherein the resistance is characterised by the presence of at least QTL1 and/or QTL2. The invention also relates to sources for obtaining said genetic determinant, representative seed of which were deposited with the NCIMB under accession numbers NCIMB 41927, NCIMB 41928, NCIMB 42068, and NCIMB 42069. The invention further relates to seeds and progeny of the plant and to its fruits and processed fruits. In addition the invention relates to molecular markers linked to PepMV resistance conferring QTLs and the use thereof. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is related to commonly assigned application Ser. No. 07/863,996, entitled "MULTIPATH DETECTOR USING PHASE COMPARISON OF STEREO PILOT SIGNAL", filed concurrently herewith and incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates in general to radio receivers with reduced distortion during multipath events, and more specifically to an FM stereo receiver with improved stereo operation during multipath events.
The problem of multipath distortion in radio receivers is well known. Multipath occurs when radio frequency (RF) signals following direct and indirect (i.e. reflected) paths from a transmitter to a receiver interfere with each other at the receiver Reflections can be caused by hills and buildings, for example.
Constructive and destructive interference of signals caused by interaction between the reflections and the direct line of sight transmission causes both signal distortion and rapid fluctuations in the received field intensity, especially in moving vehicles.
Multipath is a particularly annoying problem in reception of FM stereo broadcasts. A standard FM stereo signal includes a 19 kHz pilot carrier which is transmitted for the purpose of recovering the L-R frequency-multiplexed stereo signal When a multipath event occurs, the FM carrier signal experiences an impulse phase shift. The phase shifted FM signal is applied to the input of an RF mixer in the typical superheterodyne receiver. Due to the nonlinear characteristics of the mixer, the phase distortion is intensified and the duration of the phase disturbance is lengthened. The phase disturbance continues to lengthen in each succeeding section of the receiver. Demodulation of the FM signal produces a phase-shifted pilot signal which is then applied to the stereo decoder. The phase shift causes an abrupt unlocking of the phase-locked loop (PLL) normally employed in the stereo decoder to regenerate the pilot carrier. A rasping sound is heard in the audio output when the PLL is violently pulled out of lock by the multipath interference.
Prior art radio receivers are known wherein stereo separation is decreased during a multipath event in order to reduce the objectionable sounds associated with multipath. However, stereo separation cannot be changed fast enough to suppress all the multipath distortion. Furthermore, changing the stereo separation is itself a type of undesirable distortion. In addition, changing the stereo separation fails to correct for the lengthening of the multipath disturbance in each section of the receiver.
SUMMARY OF THE INVENTION
It is a principal object of the present invention to minimize multipath disturbances in a radio receiver.
It is further object of the present invention to reduce the impact of the property of multipath disturbance lengthening in each section of a receiver.
It is another object of the invention to avoid violent unlocking of a phase-locked loop in an FM stereo decoder.
These and other objects are achieved in the present invention by taking certain actions upon the detection of a multipath event. The power supply to an RF mixer in the receiver is interrupted upon detection of multipath, thus preventing any further energy in the multipath event from reaching succeeding sections of the receiver (where the impact of the distortion would otherwise be lengthened). The power is restored to the RF mixer before the loss of signal becomes audible, e.g., less than about 5 milliseconds.
In another aspect of the invention, noise caused by unlocking of the phase-locked loop in a stereo decoder is prevented by increasing the time constant of the PLL loop filter during the multipath disturbance. Thus, the phase-locked loop is not responsive to the random phase errors accompanying the multipath event.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a block diagram showing an FM stereo receiver according to the present invention.
FIG. 2 shows propagation of a multipath disturbance as occurs in a prior art receiver without the corrective actions of the present invention.
FIG. 3 is a schematic diagram showing an improved phase-locked loop according to the present invention.
FIG. 4 shows the multipath control signal of the present invention.
FIG. 5 plots a preferred control curve for the duration of the multipath control signal in dependence on multipath severity.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows an FM stereo receiver 10 including an antenna 11 for receiving RF signals which may at times be subject to changing multipath interference, e.g., in an automobile. RF signals from antenna 11 are coupled through an RF filter 12 to an RF amplifier 16. Amplified RF signals from amplifier 16 are coupled to one input of a mixer 17. A power supply voltage +V is supplied at a terminal 14 and through a power switch 15 to RF mixer 17 when power switch 15 is closed. A mixing signal is provided from a local oscillator 18 to another input of mixer 17.
The output of mixer 17 is provided to an IF section 20 for providing IF filtering and amplification to produce an IF signal. An FM demodulator 21 demodulates the IF signal from IF section 20 to produce a baseband signal.
If the received broadcast is an FM stereo broadcast, then the demodulated signal includes a baseband stereo sum channel, a 19 kHz pilot signal, and stereo difference channels modulated on a suppressed 38 kHz subcarrier. These are all input to stereo decoder 22 which generates left and right stereo signals which are coupled through a mute circuit 23 to amplifiers 24 and 25 and speakers 26 and 27.
Receiver 10 further includes a multipath detector/minimizer 30 for sensing the onset of multipath distortion. Minimizer 30 may, for example, be connected to receive the IF signal from IF section 20 and/or the demodulated FM signal from FM demodulator 21 in order to detect multipath events. For example, it is known to detect multipath by measuring fluctuations in the received signal strength of the IF signal. Alternatively, multipath can be detected by measuring particular noise components in the demodulated FM signal. A preferred technique for detecting multipath by measuring phase shifts in the pilot signal is disclosed in related application Ser. No. 07/863,996, which is mentioned above.
Minimizer 30 is connected to Power switch 15 so as to remove power from RF mixer 17 during a multipath event. When power switch 15 is opened, the RF mixer output is quickly disabled and the phase distortion accompanying the multipath event is stopped at the mixer output. In a preferred embodiment, the length of time that the mixer is disabled is determined by the severity of the multipath event, e.g., the magnitude of the phase shift in the multipath event. The time during which the RF mixer is disabled must have a duration less than about 5 milliseconds to avoid audible distortion.
Minimizer 30 is also connected to stereo decoder 22 for controlling the time constant of the stereo decoder phase-locked loop. In the absence of multipath, the time constant of the phase-locked loop has a conventional value allowing the phase-locked loop to maintain lock on the stereo pilot signal. Upon the occurrence of multipath, the time constant is lengthened to maintain a stable (i.e., latched) output in the phase-locked loop. With the PLL latched, the regenerated pilot signal used in the stereo decoder maintains a fixed phase and frequency and is substantially unaffected by the multipath-induced impulse phase shift of the stereo pilot signal. Preferably, the phase-locked loop is latched during the same time period when the RF mixer is disabled. If the multipath event has ended by the time that the phase-locked loop is unlatched, then the phase-locked loop output should be substantially in phase with the multipath-free stereo pilot signal and the phase-locked loop will maintain lock. Thus, abrupt changes in the phase-locked loop output signal, which would cause the undesirable rasping sound heard at the speaker output, are avoided.
Minimizer 30 may be further coupled to a mute circuit 23 to provide audio blanking during the multipath disturbance. Power switch 15, stereo decoder 22, and mute circuit 23 are preferably all controlled by a single Multipath Detect Signal from minimizer 30.
FIG. 2 illustrates the lengthening of a multipath disturbance in a prior art receiver. Curves A-E in FIG. 2 show the magnitude of the phase disturbance at points A-E of FIG. 1 which would occur without minimizer 30. An impulse phase shift in the stereo pilot signal occurs at point A (the input to the RF mixer). Curves B, C, D and E show the increased duration of the phase disturbance at points B, C, D, and E of FIG. 1 which would occur in a prior art receiver.
FIG. 3 illustrates a phase-locked loop (PLL) 31 contained in stereo decoder 22 to provide a regenerated pilot for purposes of demodulating the stereo difference channel. Use of a regenerated pilot signal is conventional in stereo decoders. The received 19 kHz stereo pilot signal is provided to a phase detector 32. The output of phase detector 32 is connected to a loop filter 33 having its output connected to the input of a voltage controlled oscillator (VCO) 34. The output of VCO 34 comprises a 38 kHz regenerated pilot signal used to demodulate the stereo difference channel. The regenerated pilot signal is also connected back to a second input of phase detector 32 through a divide-by-2 circuit 40. The output of divide-by-2 circuit 40 is a 19 kHz signal that is in quadrature (i.e., phase shifted by 90°) with respect to the stereo pilot signal.
Loop filter 33 is specially adapted to provide a switchable time constant for purposes of latching PLL 31 at a long time constant in response to the Multipath Detect signal. Thus, a field-effect transistor (FET) 35 has its gate connected to receive the Multipath Detect Signal from minimizer 30. The source and drain of FET 35 are connected to respective ends of a resistor 36. The parallel combination of FET 35 and resistor 36 is connected in series with a resistor 37 between the output of phase detector 32 and the input of an operational amplifier (op amp) 38. A capacitor 39 is connected between the input and output of op amp 38. The output of op amp 38 is connected to the input of VCO 34.
The Multipath Detect Signal employs negative logic signals so that FET 35 is rendered conductive in the absence of multipath and resistor 36 does not affect the time constant. Loop filter 33 acts as a Proportional-integral controller providing a time constant determined by resistor 37 and capacitor 39 as is conventional in the art. In the presence of multipath, however, FET 35 is rendered nonconductive thereby adding the resistance of resistor 36 to the time constant circuit. Resistor 36 has a high resistance and causes the phase-locked loop to be latched with a long time constant so that the regenerated pilot is temporarily fixed in phase and frequency.
FET 35 is preferably an enhancement mode device which is rendered conductive in response to a positive voltage from minimizer 30. FIG. 4 shows the Multipath Detect Signal wherein a high logic level voltage indicates a normal condition and a low logic level voltage indicates a multipath event. A multipath event is detected at t 1 and the low Multipath Detect Signal has a duration from t 1 to t 2 .
The duration of the low Multipath Detect Signal (i.e., the time during which corrective action is taken in the receiver) is determined by the severity of the multipath event. In the preferred embodiment, the severity of a multipath event is determined by the phase magnitude of the phase shift detected in the stereo pilot signal. The magnitude of the impulse phase shift can be determined using the detector described in co-pending application Ser. No. 07/863,996. Alternatively, the severity of a multipath event can be defined as the change in received signal strength of the FM signal or the noise power in the measured multipath noise, depending on the method used to detect multipath.
FIG. 5 plots the duration of a low Multipath Detect Signal against the severity of the multipath event. At less than a predetermined level of severity, no corrective action is taken. At a threshold level of severity, a multipath detect signal having a minimum duration of about 50 microseconds is produced by the multipath detector/minimizer. With increasing severity of the multipath event, an increasing duration is employed up to a maximum duration of 5 milliseconds. Any muting or disabling of the RF mixer extending for longer than 5 milliseconds would create objectionable noise in the output of the receiver.
While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention. | A frequency modulation (FM) stereo broadcast receiver detects the onset of multipath interference and initiates corrective action to minimize the audible effects of multipath. Under an unacceptable multipath interference condition, a multipath detection signal disables the FM RF mixer thereby preventing any further energy in the multipath event from entering succeeding sections of the receiver. This action reduces noise generated by multipath interference and allows the output to return to normal in a shorter time. In another aspect of the invention, a phase-locked loop employed in a stereo decoder circuit is latched during the multipath disturbance in order to avoid rapid changes in the phase of the regenerated pilot employed in the stereo decoder. | 7 |
[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/242,006, filed Sep. 14, 2009, and U.S. Provisional Patent Application Ser. No. 61/288,163, filed Dec. 18, 2009, the entire disclosures of which are incorporated herein.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention are generally related to selectively adjustable devices having at least one hook adapted for securing a handbag.
[0003] Additionally, one embodiment of the invention employs arms for selectively associating the device and associated handbags with a table or door.
BACKGROUND OF THE INVENTION
[0004] People who carry a purse, backpack, luggage, attaché, etc. (hereinafter “handbag”) often have difficulty finding acceptable storage for the same at a restaurant, for example. More specifically, it is desirable to keep one's belongs in close proximity while dining to prevent or deter theft. One simple way to accomplish this goal is to place the handbag on the floor adjacent to one's chair, which may be undesirable as the often expensive handbag may be damaged or soiled. Alternatively, one may place their handbag on the table, which reduces space available for food and drinks. Some other individuals choose to dine with their handbags on their lap, which is cumbersome and uncomfortable.
[0005] Devices, also known as “hangers”, for associating a handbag from a table are often foldable and stored within the handbag when not needed. Generally, foldable hangers include a member for engagement to a top surface of the table and a downwardly disposed hook that receives a strap or handle of the handbag such that the handbag rests underneath the table, out of view and off the floor.
[0006] The configuration of handbag hangers has not changed in a number of years, as evidenced by a comparison of U.S. Pat. Nos. D300,882 and 4,194,714 with U.S. Pat. Nos. D435,733, D517,732 and U.S. Patent Application Publication No. 2005/0161570, which are incorporated by reference herein. The handbag hangers of the prior art have many drawbacks in that they are not additionally equipped to engage a top edge of a vertical surface, for example, a door or wall of a bathroom stall. More specifically, often there is no convenient place to engage the handbag hangers of the prior art to a bathroom stall, which forces an individual to place their belongings on an often soiled and germ-ridden floor.
[0007] Thus it is a long felt need to provide a foldable device for selectively associating a handbag with a horizontal and/or vertical surface, such as a table and a door, respectively.
SUMMARY OF THE INVENTION
[0008] It is one aspect of the present invention to provide a selectively foldable device that secures a handbag and associates the same with a horizontal surface or vertical surface. More specifically, one embodiment of the present invention includes a table engagement portion and a hook wherein a handbag is hung beneath the table similar to that of traditional hangers described above. In addition, a selectively deployable door or auxiliary arm is provided that is used to associate the device with a door or wall of a bathroom stall. Embodiments of the present invention can be used by men, women or children and can remain interconnected to the handbag or stored when not in use. The various hooks of the inventions described herein may also be used to hang jackets, coats, hats, etc.
[0009] It is another aspect of some embodiments of the present invention to provide a handbag securing device comprised of a table portion that may be used as a handle. The other portion of the device normally used to receive a handbag is designed to receive at least one grocery bag to facilitate carrying the same. One skilled in the art will appreciate that embodiments of the present invention may include other features, which will be described below. Furthermore, the device shown below may be incorporated into a key chain and may be selectively associated to stroller or bike. The handbag hook described herein may also be used to attach the handbag to a shopping cart, to help prevent or deter theft. To that end, the device may employ a lock to help ensure the handbag remains secured to the device, cart, etc.
[0010] It is another aspect of some embodiments of the present invention to provide a foldable device that accommodates advertisements or logos. More specifically, one skilled in the art will appreciate that the devices shown in detail below may include various surfaces that are apt to employ advertising. In addition, the contemplated foldable device may be specifically shaped, colored, include two or three dimensional designs or indicia, employ unique surface textures, etc., i.e., customized to meet a desired feel.
[0011] It is another aspect of some embodiments of the present invention to provide a device with gripping members. More specifically, portions of the devices that are designed to engage horizontal or vertical surfaces may be made of a rigid material, such as metal. In order to enhance engagement of those portions to the horizontal/vertical surfaces, and to prevent damage thereto, rubber or any other compliant material may be provided on the engagement portions.
[0012] It is another aspect of embodiments of the present invention to provide a handbag securing device that accommodates at least one mirror. Furthermore, whistles, lights, weapons, mace, nail files, may also be incorporated into some embodiments of the present invention. An integrated clock, a makeup compact, etc. may be included. The device may also possess storage locations for pills. In one embodiment of the present invention, a garage or car door opener is integrated into the device. Other embodiments of the present invention include a money storage location. Some embodiments employ a GPS tracking system or the like so that parents can monitor a minor's whereabouts, emergency service personnel can be quickly notified of an injured person's whereabouts, a lost handbag may be located, or a lost individual can find their way home or be found. A location for an electronic data card, which may be selectively associated with a USB cord may be provided. Embodiments may also employ a USB port for interconnection with a digital media device, such as a flash drive. Other embodiments include an LED or other integrated screen. The device may thus be linked (via Blue Tooth, for example) to a computer, a wireless signal, a cellular phone, etc. to send/receive data. For example, one could discretely check weather, stock quotes, email notifications, voice mail notifications, etc. while sitting at a dinner table without having to access their cellular phone or computer.
[0013] It is yet another aspect of embodiments of the present invention to provide a device having an auxiliary arm that is selectively deflectable. More specifically, one embodiment of the present invention functions similar to a carabineer, wherein the auxiliary arm, which is used to associate the device to a top portion of a bathroom stall, for example, is able to selectively deflect. The auxiliary arm is separated into a first portion and a second portion that are hingedly interconnected and biased by a spring. For example, a leaf spring is employed that allows an extension protruding from the auxiliary arm to flex to facilitate receipt of a handbag onto the hook, which will be evident upon review of the figures provided herewith.
[0014] One embodiment of the present invention is fabricated from plastic or other lightweight material. This embodiment of the present invention is similar to those described above and will be understood more clearly upon review of the figures related to the same. An auxiliary arm is included that employs a capture hook that receives a capture ring that is rotatably interconnected to a hook that functions similar to a carabineer. The handbag hook is operably associated with a table arm by way of a pin. In operation, the hook is deflected upwardly to overcome a spring, which directs the capture ring along an inclined edge of an extension associated with the door arm. Deflection of the hook thus rotates the ring inwardly as it travels along the inclined edge. Once released, the spring forces the handbag hook downwardly, thereby positioning the capture ring away from the capture hook which allows for free rotation of the capture ring so that a handle of the handbag may be positioned on the hook. The capture ring may then be pulled towards the capture hook to allow seating of the capture ring on the capture hook to secure the handbag.
[0015] It is another aspect of the present invention to provide a selectively foldable device for securing a handbag, comprising: a primary hook having a first end, a second end, and having a portion adapted to receive the handbag; an auxiliary arm with a first portion operably interconnected to said primary hook and a second portion operably interconnected to said first portion; an extension with a first end interconnected to said second portion and a second end; a head operably interconnected to said first end of said primary hook, said head having a surface adapted to engage a horizontal surface; wherein in a first, folded position of use said auxiliary arm and said extension is positioned such that said second end of said gate is positioned adjacent to said second end of said primary hook; and wherein in a second position of use said surface of said head adapted to be engaged on a horizontal surface and said auxiliary arm and associated extension are positioned such that said second end of said primary hook and said second end of said gate are positioned away from each other so that said head may be adapted to be positioned on said horizontal surface and said second end is adapted to be positioned beneath said horizontal surface.
[0016] It is still yet another aspect of the present invention to provide a selectively foldable device for securing a handbag, comprising: a primary hook; an auxiliary arm associated to said primary hook, said auxiliary arm including an extension that selectively coincides with an end of said primary hook; and a head adapted to engage a horizontal surface associated with said primary hook.
[0017] 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. 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. 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, components, etc. in this Summary of the Invention. Additional aspects of the present invention will become more readily apparent from the Detail Description, particularly when taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions.
[0019] FIG. 1 is a perspective view of one embodiment of the present invention;
[0020] FIG. 2 is a front elevation view of FIG. 1 ;
[0021] FIG. 3 is a cross-sectional view of FIG. 2 ;
[0022] FIG. 4 is a perspective view of the embodiment shown in FIG. 1 shown in a second position of use, for positioning a handbag beneath a table;
[0023] FIG. 5 is a front elevation view of the embodiment shown in FIG. 1 in third position of use, for positioning a handbag on a door;
[0024] FIG. 6 is a perspective view of a luggage tag of one embodiment of the present invention that possesses a hook adapted for engagement on a door;
[0025] FIG. 7 is a perspective view similar to that in FIG. 6 wherein the device is shown in a second position of use;
[0026] FIG. 8 is a front perspective view of another embodiment of the present invention;
[0027] FIG. 9 is an elevation view of FIG. 8 ;
[0028] FIG. 10 is a perspective view of the embodiment shown in FIG. 8 shown in a first closed position of use;
[0029] FIG. 11 is a perspective view of another embodiment of the present invention;
[0030] FIG. 12 is a perspective view similar to that of FIG. 11 wherein a door arm is shown in a second position of use;
[0031] FIG. 13 is a perspective view of another embodiment of the present invention;
[0032] FIG. 14 is a front elevation view of FIG. 13 ;
[0033] FIG. 15 is a perspective view of the device of FIG. 13 shown in a second position of use for engagement with a horizontal surface;
[0034] FIG. 16 is a bottom perspective view of FIG. 13 shown in a second position of use for engagement with a horizontal surface;
[0035] FIG. 17 is a front view of the device of FIG. 13 shown engaged on a table and holding a purse;
[0036] FIG. 18 is a perspective view of FIG. 13 shown in a third position of use for engagement with an upper edge of a vertical surface;
[0037] FIG. 19 is a front elevation view of the device of FIG. 13 shown associated with a vertical surface; and
[0038] FIG. 20 is a front elevation view of another embodiment of the present invention;
[0039] FIG. 21 is a front elevation view similar to that of FIG. 20 wherein a door arm is shown in the second position of use for receipt of a handbag;
[0040] FIG. 22 is a front elevation view of the handbag of FIG. 20 wherein a head has been rotated for engagement on a table and the door arm has been rotated for engagement on an upper edge of a vertical surface;
[0041] FIG. 23 is an exploded detail view of the door arm of one embodiment of the present invention;
[0042] FIG. 24 is a door arm of one embodiment of the present invention having a first portion and a second portion;
[0043] FIG. 25 is the door arm of FIG. 24 shown in the second position of use;
[0044] FIG. 26 is a front elevation view of an embodiment of the present invention similar to the embodiment of FIG. 20 ;
[0045] FIG. 27 is a plan view of the head of some embodiments of the present invention;
[0046] FIG. 28 is a front elevation view of the head shown on FIG. 27 ;
[0047] FIG. 29 is a perspective view of another embodiment of the present invention;
[0048] FIG. 30 is a cross-sectional view of FIG. 29 ; and
[0049] FIG. 31 is the device of FIG. 29 shown in a position that is adapted to accept a handbag.
[0050] To assist in the understanding of the present invention the following list of components and associated numbering found in the drawings is provided herein:
[0000]
#
Components
2
Handbag securing device
6
Table arm
10
Door arm
12
Extension
14
Post
18
Hook
22
Riser
26
Lock
30
Outer protrusion
34
Inner protrusion
38
Cavity
42
Appendage
46
Indent
100
Luggage tag
104
Sleeve
108
Door arm
200
Handbag securing device
202
Table portion
206
Hinge
208
Hanging purse portion
212
Hook
216
Door arm
220
Hinge
300
Handbag securing device
304
Head
308
Primary hook
312
Post
316
Groove
320
First surface
324
Recess
328
Second surface
332
Recess
334
Notch
336
Table
340
Handbag
344
Door arm
346
Extension
348
Wall
352
Hook end
360
Pin
364
Channel
368
Channel opening
400
Handbag securing device
404
Primary hook
408
Hook end
412
Linear portion
414
Post
416
Post arm
420
Door arm
424
Head
428
Spring
432
Notch
434
Extension
440
Spring
444
First portion
448
Second portion
450
Hinge
454
Plunger
458
First hole
462
Second hole
466
Notch
470
Cavity
474
Groove
478
Channel
482
Sidewall
600
Handbag securing device
604
Door arm
608
Bore
612
Post
616
Spring
620
Capture hook
622
Extension
624
Table arm
628
Capture hook
632
Upper end
636
Capture ring
638
Primary hook
640
Inclined portion
644
Boss
646
Recess
[0051] It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the 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.
DETAILED DESCRIPTION
[0052] Referring now to FIGS. 1-5 , one embodiment of a handbag securing device 2 (hereinafter “device”) is shown. The device 2 includes a table arm 6 and door arm 10 that are rotatably interconnected to a post 14 . The door arm 10 may also include an extension 12 . The post 14 is interconnected to a hook 18 for securing a handbag that may also include a riser 22 . The riser 22 and the extension 12 cooperate to form a lock 26 , similar to that employed by a carabineer.
[0053] With specific reference to FIG. 3 , the extension 12 includes an outer protrusion 30 and inner protrusion 34 with a cavity 38 therebetween. The cavity 38 receives an appendage 42 of the riser. The outer protrusion 30 may include at least one indent 46 that receives a portion of the appendage 42 to provide a selectively breakable locking fit. That is, the contemplated interconnection is easy to open when an individual wishes to use the door arm 10 , but maintains the extension 12 against the riser 22 when the extension is not in use. As can be appreciated by one skilled in the art, this allows the device to be easily folded and stored in the position of use shown in FIGS. 1 and 2 .
[0054] Referring now to FIG. 4 , the device 2 is shown ready to position a handbag adjacent to a horizontal surface such as a table. In this configuration, the table arm 6 is rotated about the post 14 for engagement onto a top surface of the table. The door arm 10 is also rotated to break the connection between the extension 12 and the riser 22 . This allows an individual to place a handle or other portion of their handbag onto the hook 18 . When the table arm 6 is engaged on the top surface of the table, for example, the handbag will rest beneath the table and hang above the floor.
[0055] Referring now specifically to FIG. 5 , to associate the device 2 with a vertical surface, the door arm 10 is rotated about the post 14 , which allows the door arm 10 to be placed over a wall of a bathroom stall, for example. The hook 18 is then exposed to allow an individual to place their handbag or jacket thereon.
[0056] Referring now to FIGS. 6 and 7 , another embodiment of the present invention is shown that is in the form of a luggage tag 100 . Often it is desirable to store luggage off the floor of an airport bathroom, for example. Here, the luggage tag 100 possesses a sleeve 104 that allows selective rotation of an associated door arm 108 . In operation, the door arm 108 is rotated away from the luggage tag 100 and used to interconnect to a door. The luggage tag 100 is made of sufficient strength to support the weight of the luggage to which it is connected.
[0057] Referring now to FIGS. 8-10 , yet another device 200 is shown that includes a table portion 202 that is interconnected via a hinge 206 to a hanging portion 208 . The hanging portion 208 has a distal end with a hook 212 for receiving a handbag. When not in use, the hanging portion 208 is folded relative to the table portion 202 and fits within a recess (not shown) of the table portion 202 . When in use, the table portion 202 engages a top surface of a table with the hook 212 positioned to receive the handbag and suspend it beneath the table top. Upon review of the figures, it will be appreciated by one of skill in the art, that the table portion 202 has sufficient volume to accommodate a whistle, pill box, a light, a nail file, mace, and other items mentioned above. The table portion 202 also may be used as a handle to facilitate carrying groceries, for example, wherein the hook 212 accommodates the handle associated with at least one grocery bag.
[0058] Referring now to FIGS. 11 and 12 , another embodiment of the present invention similar to that shown in FIGS. 8-10 is shown that also includes an additional door arm 216 interconnected by a hinge 220 to the table portion 202 of the device 200 . In operation, the door portion 216 is selectively rotated relative to the table portion 202 and is used to engage an upper surface of a bathroom stall, for example.
[0059] Referring now to FIGS. 13-19 , a device 300 of another embodiment of the present invention is shown. The device 300 includes a head 304 that is selectively interconnected to a primary hook 308 . The primary hook 308 includes a post 312 that is selectively positionable within a groove 316 integrated into the head 304 . The head 304 of one embodiment includes a first surface 320 with a recess 324 and a second surface 328 with a recess 332 . In a second position of use shown in FIG. 15 , for example, the head 304 is rotated wherein the post 312 is fixed within a notch 334 such that the second surface 328 is oriented for engagement onto a table 336 so that a handbag 340 may be secured on the primary hook 308 . The device 300 also includes a door arm 344 that is rotatably interconnected to the primary hook 308 for engagement to an upper surface of a wall 348 which also positions the primary hook 308 in such a way to receive a purse, coat, or other item.
[0060] FIGS. 13 and 14 show the device 300 in a first position of use with the head 304 , primary hook 308 and door arm 344 generally aligned. In this configuration, the post 312 is positioned within the groove 316 of the head 304 . This first position of use facilitates storage within a handbag, or displayed outside a handbag wherein the primary hook 308 is fastened about a strap thereof, for example. The door arm 344 may employ an extension 346 that cooperates with the free end of the primary hook 308 to form a substantially closed loop. Further, the primary hook 108 and extension 346 may terminate in a hook end 352 . The hook ends may be spherical, as shown, or may be of other shapes as will be appreciated by those of skill in the art. Further, the hook ends 352 of one embodiment of the present invention include a threaded tapped hole (not shown) that is engaged on a threaded end of the extension 346 and the primary hook 308 (not shown). As such, the hook ends 352 may be selectively removed from the primary hook 308 and/or extension 346 to allow the integration of other items onto the primary hook 308 or extension 346 . For example, it is contemplated that various beads or other accoutrements may be added to the device 300 to enhance or personalize the appearance thereof. For example, a series of beads and/or charms may be added to the primary hook 308 and/or extension 346 . Further, at least one wine glass charm may be selectively associated with the device that may be removed and associated with a wine glass to mark the same.
[0061] The recess 324 is optional and one skilled in the art will appreciate that the first surface 320 may be continuous. The recess 324 may be used to receive an artistic feature, such as a decorative inlay. Those skilled in the art will appreciate that the head 304 may include a door wherein the recess functions as a storage location suitable for pills, for example. The recess may also accommodate a video screen that is associated with a battery integrated into the head 304 . The contemplated screen may be used to display videos or pictures and/or other information may be associated with the world wide web. The recess 324 may also be configured to receive a static photo or photos. The recess 324 may also receive information related to the owner of the purse and function as a luggage tag. Further, the head 304 may be such size to accommodate a music playing device, similar to an iPod®, for example, wherein the head 304 may be interconnected to ear phones or may include a speaker. The head 304 may also include a wireless information transmitting/receiving device (i.e., a Bluetooth®) such that the device 300 may interact wirelessly with a communications device to display information on a panel integrated into the head 304 or an audio device integrated into the head. For example, the device 300 may be configured to function as a speaker phone or may receive and display real time news or stock market data. In order to conserve power, the recesses and/or surfaces of the head may also accommodate a solar panel wherein the device 300 obtains the power needed to run the associated Bluetooth® device, video screen, music device, calculator, etc.
[0062] In order to lock the head 304 with respect to the door arm 344 to achieve the position of use shown in FIGS. 13 and 14 , the head 304 may include a channel 364 that selectively receives a pin 360 associated with the door arm 344 . This mechanical interconnection maintains the position of the head 304 relative to the door arm 344 when the post 312 is positioned within the groove 316 . By pulling the head 304 away from the post 312 , the pin 360 is repositioned within the channel 364 such that the pin 360 may be removed from a channel opening 368 as shown in FIG. 16 . One skilled in the art will appreciate that the head 304 may be selectively associated with the auxiliary hook 344 by other mechanisms, such as a magnet.
[0063] Referring now to FIGS. 15-17 , the device 300 is shown in a second position of use that is adapted to engage a table 336 . Here, the head 304 has been rotated with respect to the post 312 by pulling the head 304 in a direction transverse to the post 312 . In one embodiment, the post 312 terminates in an arm (not shown, see for example # 416 of FIG. 20 ) positioned within the head 304 . In addition, the head 304 is preferably interconnected to the arm by way of a spring (not shown) that allows the head 304 to be pulled away, rotated around the arm and then released. After the head 304 is released, it is pulled by the spring towards the post 312 to position an upper part of the post 312 , the notch 334 , thereby locking the head 304 in the second position of use shown. FIG. 15 shows the door arm 344 rotated such that a handbag 340 is secured on the primary hook 308 . The notch 334 secures the head 304 in the position for engagement onto a table. The door arm 344 may remain rotated away from the end of the primary hook 308 as shown, for example, in FIG. 16 . The second surface 320 also may have a recess 332 to receive a gripping member made of silicone rubber, for example, to facilitate engagement of the head 304 to the table 336 . One of skill in the art, however, will recognize that the gripping member may be integrated directly into the second surface 328 wherein no recess is required.
[0064] Once the head 304 is swiveled as shown, the second surface 328 of the head 320 is placed on a top surface of a table 336 wherein the first surface 320 faces upwardly. The primary hook 308 is then positioned under the table 336 and is able to receive the handbag 340 . Finally, the door arm 344 may then be swiveled into place wherein the hook ends 352 of the primary hook 308 and the auxiliary hook 344 generally coincide.
[0065] Referring now to FIGS. 18 and 19 , a third orientation of the device 300 is shown wherein the door arm 344 is rotated away from the primary hook 308 with their respective hook ends 352 separated. The door arm 344 includes an upper surface that engages an upper edge of a vertical wall 348 so that the primary hook 308 is positioned on one end of the wall 348 and is able to receive the handbag 340 as shown. In operation, this configuration would be used in conjunction with a bathroom stall wherein the door arm is placed on a wall 348 adjacent to the user wherein the handbag 340 is firmly secured close to the individual using the bathroom facilities.
[0066] Referring now to FIGS. 20-25 , yet another handbag securing device 400 of the present invention that employs components similar to that of a carabineer is provided. More specifically, this embodiment of the present invention includes a primary hook 404 for receiving a handle of a handbag. The primary hook 404 includes a hook end 408 that is preferably selectively interconnected to an end of the primary hook. The primary hook 404 has a substantially linear portion 412 that is associated with a post 416 . A door arm 420 that is rotatably interconnected to the post 414 . The device 400 also includes a swiveling head 424 , similar to that described above that is selectively biased by a spring 440 associated with a post arm 416 . To swivel, the head 424 is pulled away from the post 416 , rotated and allowed to relax into a notch 432 to maintain the orientation of the same. The rotation of the head 424 is shown in FIG. 21 .
[0067] The door arm 420 includes a first portion 444 and a second portion 448 that are interconnected by way of a hinge 450 . The first portion 444 and the second portion 448 are biased by the spring 428 , such as a leaf spring that allows an extension 434 associated with the return to a first position of use, shown in FIG. 21 , for example, when there is no force acting on the extension 434 .
[0068] In operation, the head 424 is pulled away from the post arm 416 as described above rotated, and allowed to relax against the post 414 such that the post 414 rests in the notch 432 . The handle of the handbag or attaché would then be engaged against an extension 434 associated with the door arm 420 towards the linear portion 412 , thereby overcoming the spring force and allowing the extension 434 to rotate about the hinge 450 . After the handbag is securely located on the hook 408 , the extension 434 would snap back into place due to the force exerted by the spring 440 . Thus, the handbag would be secured within the boundaries of the door arm 420 , extension 434 and primary hook 408 .
[0069] FIG. 22 also shows the door arm 420 rotated in a second position of use that allows the device 400 to be associated with a vertical surface, such as a bathroom stall. The door arm 420 may include a plunger 454 , which also may be spring loaded, that is adapted to interface with a portion of the head 424 when in a first position of use (FIG. 20 ) to maintain the head 424 in the first position of use. The spring 440 may be the same spring associated with the extension 434 wherein rotation of the extension 434 , described below, will allow the pin 436 to retract within the door arm 420 to allow the head 424 to move as contemplated.
[0070] The plunger 454 and spring 440 combination of one embodiment of the present invention is shown in FIGS. 23-25 . Here, the first portion 444 and second portion 448 of the door arm 420 area hingedly interconnected and associated with a spring 440 . The spring 428 is flexed by rotation of the first portion 444 relative to the second portion 448 , which also forces a plunger 454 upwardly to lock the head relative to the door arm 420 . When in a first position of use, the plunger 454 is depressed within the door arm 420 , thereby allowing the head to move. The plunger 454 may have a rounded profile that enhances deflection into the door arm 420 when the plunger 454 is contacted by the head 424 . The plunger 454 is received within a groove (not shown), or an aperture when the head 424 is in the first position of use.
[0071] To secure the device 400 to a table, the head 424 is pulled in a direction away from the post 414 , thereby compressing the spring 428 integrated therein. Next, the head 424 is rotated as described above in order to place a gripping member (not shown) in an orientation to be received on a table. The door arm 420 may then remain in place or be rotated outwardly as shown in FIG. 22 to allow placement of the handbag on the hook 408 . When used in a first position of use, the first portion 444 of the door arm 420 is rotated with respect to the second portion 448 of the door arm 420 , thereby moving the extension 434 to allow the device 400 to be incorporated onto a handle of a handbag. The deflection of the first portion 444 moves the plunger 454 upwardly by the compressed spring, thereby locking the head 424 relative to the door arm 420 .
[0072] FIGS. 26-28 show another embodiment of the present invention similar to that of FIG. 20 wherein the door arm 420 is of a different construction. More specifically, the first portion 444 of the door arm 420 is shown in an open position prior to final assembly. The door arm includes a first hole 458 and a second hole 462 for receipt of the post 414 and to accommodate the plunger 454 , respectively. In this embodiment of the present invention, the spring 428 is a torsion spring as opposed to the spring shown in FIGS. 23-25 provided above. The head 424 of this embodiment of the present invention is operably interconnected to the post arm 416 that further includes a notch 466 . A spring 428 is configured such that an end portion thereof is seated in the notch 466 and thus held in place. In operation, the spring 428 is integrally positioned within a cavity 470 of the head 424 wherein the post arm 416 is placed through the spring 428 . When the notch 466 of the post arm 416 encounters the end of the spring 428 , the spring 428 snaps into the notch 466 to secure the post arm 416 within the head 424 .
[0073] Referring now specifically to FIGS. 27 and 28 , the head 424 of one embodiment of the present invention is shown that includes a groove 474 and a channel 478 . The channel 478 includes a contoured sidewall 482 to facilitate receipt of the plunger (see FIG. 26 ). One skilled in the art will appreciate that the top surface of the head and the bottom surface of the head may each include a channel 478 . Similarly, the groove 474 may extend from the top surface of the head to the bottom surface of the head. One skilled in the art will appreciate that such an elongated groove may be employed on other embodiments of the present invention described herein such that the head 424 may be rotated and locked into the first position of use in at least two ways.
[0074] FIGS. 29-31 , show another handbag securing device 600 of one embodiment that is made out of a lightweight material that is similar to the device shown above in FIGS. 1-5 . A door arm 604 includes a bore 608 for receiving a post 612 of the device 600 that is spring 616 biased. A capture hook 620 that is associated with an extension 622 that is associated with the door arm 604 . In operation, a table arm 624 is pulled away from the door arm 604 that compresses the spring 616 and pulls a capture hook 628 upwardly. In addition, pulling the capture hook 628 upward slides an upper end 632 of a capture ring 636 associated with a primary hook 638 along an inclined portion 640 of the capture hook 620 , thereby rotating the capture ring 636 as shown in FIG. 31 . The table arm 624 is then able to rotate as a boss 644 associated with the door arm 604 is removed from a recess 646 of the table arm 624 as shown in FIGS. 30 and 31 . The handbag would then be placed on the hook 638 to secure the same.
[0075] It is envisioned that this embodiment of the present invention be made out of plastic or semi-rigid materials. It is also envisioned that the capture ring 636 may alternatively be a carabineer type of interconnection or employ a living hinge. Furthermore, those of skill in the art will appreciate other aspects of the present invention described above may be incorporated in this invention, such as a door arm having a first portion and a second portion that are hingedly interconnected.
[0076] The handbag securing devices of embodiments of the invention can also be hung from a handbag and perhaps used to support other items. The device may, for example, receive grocery or shopping bags. Similarly, the device may be hung from a stroller or shopping cart.
[0077] 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. However, 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. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. | A selectively adjustable device for securing a handbag on a table is provided. The device is designed to fold into a compact shape and includes at least one surface for receiving a handbag. Other embodiments provided include a secondary arm for allowing accommodation of the device onto a vertically oriented wall or other surface. | 0 |
RELATED APPLICATIONS
This application is a continuation of application Ser. No. 571,862, filed Apr. 25, 1975, which in turn is a continuation of application Ser. No. 143,272, filed May 13, 1971 and Ser. No. 879,181, filed Nov. 24, 1969, both now abandoned.
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to constructional elements of L-shaped cross-section comprising two metal flanges joined together at right-angles each flange having at least one row of regularly spaced holes or apertures extending longitudinally thereof. Elements of this type cut to suitable lengths can be secured together by fixing means inserted through registering holes or apertures to form a variety of structural units and frameworks.
2. Description of Prior Art
Constructional elements of the type referred to above are described in the specifications of my two earlier British Pat. Nos. 696,531 and 856,780.
In my earlier British Pat. No. 696,531 I disclosed a constructional element of constant thickness and of L-shaped cross-section having a narrow flange and a wide flange, a row of holes extending longitudinally of the narrow flange, and two rows of holes extending longitudinally of the wide flange, the minimum distance between the adjacent edges of adjacent holes in each row being the same throughout each row, said distance being the same in the case of each of the three rows, the row of holes in the narrow flange and the two rows of holes in the wide flange being repetitions of one another and each consisting of a plurality of alternate round and elongated holes, the round holes all being of the same size, the elongated holes all being of the same diameter, said elongated holes being elongated transversely of the element, said elongated holes being of a width equal to the diameter of one of the round holes and of a length equal to the diameter of one of the round holes plus twice the thickness of the element, the round holes in any given row of holes being transversely aligned with the elongated holes in the next adjacent row of holes.
I later found that the element of my first mentioned patent could be rendered substantially more versatile by radically changing the number, shape, and arrangement of holes in the inner row of holes in the said wide flange; and in the L-shaped element disclosed in my later British Pat. No. 856,780 the said row consists of a plurality of holes which are alternately elongated transversely and longitudinally of the member, the transversely elongated holes being similar in size to the transversely elongated holes in the other two rows and the longitudinally elongated hole being of the same width as one of the round holes in the other two rows and of a length at least as great as the centre-to-centre distance between two of the transversely elongated holes in one of said other rows plus the diameter of one of said round holes.
I now find that the utility of such a constructional element can be further improved by altering the configuration of the holes or apertures to provide in each row a series of round holes alternating with holes which are elongated both in the longitudinal and transverse direction of the element.
SUMMARY OF THE INVENTION
According to the present invention, at least one flange of the constructional element has a row of apertures comprising apertures of a first type alternating with apertures of a second type, the apertures of the first type being capable of accommodating a fastener such as a bolt without appreciable play in the plane of the flange, whereas the apertures of the second type are arranged to afford the fastener a play of predetermined magnitude, preferably equal to twice the thickness of the flange, both parallel to and transversely of the length of the element, the apertures of the second type being elongated in both said directions for this purpose.
The first type apertures are preferably, though not essentially, circular in form and designed for use with cylindrical bolts, and the second type apertures accordingly are preferably in the form of quatrefoils defined by arcuate curves of radius equal to that of the circular apertures.
Two or more such rows of apertures can be provided in a flange and where such rows are provided in both flanges of the element the rows of apertures closest to the junction between the flanges are mutually offset so that the first type apertures in one of said closest rows register transversely with second type apertures in the other closest row, adjacent rows of apertures in anyone flange being likewise mutually offset.
It is envisaged that in a constructional element as defined above wherein two or more such rows of apertures are provided on one flange, an auxiliary row of first-type apertures may be provided at a location spaced between the outermost row of said apertures and the free edge of the flange, said auxiliary first-type apertures registering transversely with the second-type apertures in said outermost row but not themselves being interspaced by second-type apertures. Thus for a given length of constructional element the numbers of apertures in said auxiliary row will be equal to half the number of apertures in the remaining rows of the same flange.
Preferably the lateral spacing between the rows of apertures in a flange is equal to one-half the spacing, longitudinally of the element, of identical apertures in each row the spacing of the innermost row of apertures in a flange from the inner surface of the adjacent flange is preferably greater than one-half the spacing, longitudinally of the element, of identical apertures in each row plus the thickness of the flange. The spacing of the outermost row of apertures on a flange from the free edge of the flange is preferably equal to half the spacing of identical apertures longitudinally of the element.
BRIEF DESCRIPTION OF DRAWINGS
The advantages of my novel form of constructional element will become apparent from the following detailed description of several embodiments thereof, given by way of example only, taken in conjunction with the accompanying drawings in which:
FIGS. 1, 2, 1A and 2A are respectively a top plan view, a side elevation and two end sectional views of one form of constructional element;
FIGS. 3, 4 and 5 are side elevations of alternative forms of constructional elements, the corresponding end sectional views being shown in FIGS. 3A, 4A and 5A respectively;
FIGS. 6 and 7 are detailed views to an enlarged scale showing the form of apertures provided in the constructional elements illustrated in FIGS. 1 to 5;
FIGS. 8 and 8A show repsectively a top plan view and a side elevation of an overlapping splice of two nested elements of the type shown in FIG. 4;
FIGS. 9 and 9A shown respectively a top plan view and a side elevation of a butt splice between elements of the type shown in FIG. 4;
FIG. 10 is a perspective view showing a typical corner connection between constructional elements of the type shown in FIGS. 1 and 2;
FIGS. 11 and 12 are side elevations of the corner connection shown in FIG. 10;
FIG. 13 is a perspective view of a typical corner connection using constructional elements of the type shown in FIG. 3;
FIGS. 14 and 15 are respective side elevations of the connection shown in FIG. 13;
FIGS. 16 and 17 are side elevations of an alternative corner connection to that shown in FIGS. 13 to 15;
FIGS. 18 and 19 show respectively a top plan view and a front elevation of a T section connection between constructional elements of the type shown in FIGS. 1 and 2;
FIG. 20 is a perspective view of a typical corner connection using constructional elements of the type shown in FIG. 4;
FIGS. 21 and 22 are side elevations of the corner connection shown in FIG. 20;
FIGS. 23 and 24 are side elevations of a corner connection arrangement alternative to that shown in FIGS. 20 to 22;
FIG. 25 is a view corresponding to FIG. 22 showing an elevation of a corner connection employing the constructional element of FIG. 5.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to FIGS. 1, 1A, 2 and 2A there is shown a constructional element 9 comprising an L-section metal angle bar having flanges 1 and 2 of equal width and arranged mutually at right angles, the element being of constant cross-section and uniform thickness. In each of the flanges 1 and 2 is provided a line of apertures extending longitudinally thereof, circular apertures 6 alternating with non-circular apertures 7, and the circular apertures in one flange registering transversely with the non-circular apertures in the other flanges as shown.
The apertures are shown in more detail in FIGS. 6 and 7, the circular apertures or holes 6 having a radius c and the non-circular apertures or guatrefoils being elongated both longitudinally of and transversely of the length of the element. As will be clearly seen from FIG. 7 each quatrefoil 7 is defined by four regularly arranged intersecting arcuate curves of radius c the maximum dimension of the quatrefoil in each of its directions of elongation being equal to 2c plus 2d where d is the thickness of the flanges of the element. As shown in FIG. 1 the centre-to-centre distance of adjacent holes 6 along each flange equals 2a, the quatrefoils 7 being arranged symmetrically at regular intervals with respect to the holes. The distance between the line joining the centre of the holes and the free edge of the flange 1 is a, while the distance between this line and the plane of the inner surface of flange 2 is b. The dimension b should be not less than the dimension a, and in practice, for reasons which will become apparent from the following description, will usually be slightly larger.
The constructional element may be provided in standard lengths, cutting indication marks 8 being provided at regular intervals to facilitate cutting of the element into suitable shorter lengths as required. The cutting indications 8 preferably coincide with the transverse line of symmetry of successive quatrefoils 7 in the flange 2, i.e. with the centres of successive holes in the flange 1.
The constructional elements illustrated in FIGS. 3 to 5 are basically similar to the one shown in FIGS. 1 and 2 and like parts are indicated by the same reference numerals therein. In FIGS. 3 and 3A a constructional element 10 is shown having a flange 1 with a single line of apertures and a wider flange 3 having two lines of apertures as shown. The line of apertures nearest the free edge of flange 3 is arranged with the apertures thereof positioned in offset relationship with respect to the other line of apertures on that flange, i.e. the quatrefoils in one line are transversely aligned with the holes in the other line. The transverse distance between the centres of the lines of apertures on flange 3 is equal to a.
The constructional element 11 shown in FIG. 4 has a narrow flange 1 and a wide flange 4 provided with three rows of apertures 6 and 7, the apertures of these rows being offset so that the round holes in one row are transversely aligned with the quatrefoils in each adjacent row, the transverse spacing between the centres of the line of apertures being equal to a.
The constructional element 12 illustrated in FIG. 5 is generally similar to that shown in FIG. 4 but has a wide flange 5 in which the quatrefoils have been omitted from the outermost row of apertures which therefore comprises simply a series of holes 6 positioned at a centre-to-centre distance along the flange of 2a.
Referring now to FIGS. 8 and 8A there is illustrated the relationship assumed for forming an overlapping splice of two nested elements 11 of the type shown in FIG. 4 the holes 6 in the flange 1 of one of the elements being registered with the quatrefoils 7 in the corresponding flange of the other element.
It will be evident that because of the nested arrangement of the two elements, the lines of apertures in the flanges 1 will be mutually offset vertically by a distance d equal to the thickness of the material of the elements.
The cross-hatched circles 13 in these views illustrate the area of overlap between these registering apertures and thus it will be clear that any or all of the aligned apertures may be employed for securing the two elements together as by the insertion of a fastener such as a bolt therethrough. It will be noted that each fastener provided to form this joint will be capable of withstanding both longitudinal and transverse bearing forces since the nature of the overlapping apertures affords no plan to the fastener.
FIGS. 9 and 9A show the arrangement for forming a butt splice between two elements of the type shown in FIG. 4, the butt being strengthened by outer and inner elements 11b, 11a on both sides of the joint. As shown in FIG. 9A the apertures in the flange 4 of the inner element are vertically offset from the apertures in the outer element by a distance of 2b. However, by virtue of the shape of the quartrefoil apertures it is still possible to insert bolts through three nested elements as shown in the drawings. As an alternative to the arrangement shown in FIGS. 9 and 9A, the butt splice could also be made if the butted elements were moved laterally by a distance a relative to the inner and outer elements. In this case the quatrefoil 7 of the inner and outer elements would register with the circular holes 6 of the butted element.
FIG. 10 shows in perspective a corner connection between three constructional elements 9 of the type shown in FIG. 2 arranged mutally at right angles. The dimensions of the apertures 6 and 7 and their positions on the elements 9 are such that the connection may be secured by two bolts 13 inserted through registering apertures in the overlapping flanges, and lateral and vertical loads applied to the connection are applied as bearing loads upon both the bolts.
It will be observed that the constructional elements as shown in the drawings all include a small radius curvature at the junction of the flanges. Thus it will be appreciated that when elements are to be secured together at right angles as shown in FIGS. 10 and 11, the distance b between the row of apertures and the other flange of the element should be greater than centre-to-centre distance a between the apertures lengthwise of the element, if the elements are to be connected with the flanges of adjacent elements in face-to-face contact and the apertures properly registered. Preferably distance b is equal to the sum of distance a, distance d and an allowance for the radius at the flange junction.
The bolt 13 shown in plan view in FIG. 11 is in bearing between a quatrefoil 7 in flange 1 of the vertical member and a hole 6 in flange 2 of the horizontal member. The other bolt 13 is shown in FIG. 12 is in bearing between a hole 6 in flange 2 of the vertical member and a hole 6 in the flange 2 of the horizontal member. To strengthen the corner connection a diagonal brace may be added as shown in FIG. 12 and comprising a length of the element 9 bolted in position as shown.
In forming the corner connection shown in FIGS. 13 to 15 a constructional element 10 of the type shown in FIG. 3 is employed and in this connection it is possible to arrange four bolts in bearing through the registering apertures indicated by the cross-hatched circles. As shown in FIG. 14 the narrow flange 1 of the vertical element is connected to the wide flange 3 of one of the horizontal elements. FIG. 15 shows two bolts joining two holes 6 in the wide flange 3 of the vertical member to two holes 6 in the wide flange 3 of one of the horizontal members.
In the alternative connection arrangement shown in FIGS. 16 and 17 the horizontal elements 10 are joined to the vertical elements 10 at a location a distance a vertically below the location shown in FIG. 13. Thus as shown in FIG. 16 one bolt 13 joins overlapping holes 6 in the narrow flange 1 of the vertical element and the wide flange 3 of one of the horizontal elements. If the wide flange 3 of the vertical element is connected to the wide flange 3 of the other horizontal element it would be possible to connect these overlapping flanges by four blots 13 loaded in bearing as shown in FIG. 17. Thus with this connection it is possible to position five bolts to withstand lateral and vertical bearing loads.
The inverted T connection shown in FIGS. 18 and 19 provides for the bolting of two "back-to-back" vertical elements to a common cross member, bolts 13 being inserted through the registering quatrefoils in the vertical and horizontal members and being loaded in bearing. Any of the constructional elements shown in FIGS. 1 to 5 may be employed in making such a connection. The centre-to-centre distance between the bolts 13 on the flange of the horizontal members is 2a + 2d. This distance should correspond to the horizontal distance between the quatrefoils in the flanges 1 of the vertical elements which equals 2(b-d) + 2d, i.e., 2b.
The corner connection shown in FIGS. 20 to 22 is similar to the one shown in FIG. 13 but employs three constructional elements 11 of the type shown in FIG. 4. As will be seen from FIGS. 21 and 22 this corner connection may be secured by a total of eight bolts in bearing inserted through the overlapping apertures.
FIGS. 23 and 24 show a corner connection similar to that shown in FIG. 20 but with the horizontal elements displaced a distance a vertically on the vertical element. This corner connection may be secured by a total of eleven bolts inserted through the overlapping apertures as shown.
FIG. 25 is a view corresponding to FIG. 22 of a corner connection employing constructional elements of the type shown in FIG. 5 and using the same bolting pattern.
It will be evident that the connections illustrated in FIGS. 10 to 25 are all "lock joints" i.e. joints in which the fastener means, such as bolts, used in securing the connection are in bearing engagement with the edges of the apertures in the adjacent elements and are capable of withstanding bearing loads. Thus the improved constructional element of my invention is particularly suited to the fabrication of rigid structures which can withstand vertical and horizontal loadings or stresses. In no case is it necessary to resort to the use of "friction joints" i.e. joints wherein the fasteners are not in true bearing engagement in the apertures of the elements, but where the rigidity of the joint is dependent upon the frictional engagement between contacting flanges of adjacent elements of the joint, this frictional engagement being applied by the axial loading on the fasteners, such as bolts. In existing structural elements of the same general type many of the connections described above can only be achieved by employing frictional joints which have a lower strength than the preferred lock joints and which become unsatisfactory if any loosening of the fasteners occurs. The rigidity of structures fabricated with my elements, on the other hand, is not dependent upon the tightness of the bolts.
Furthermore the geometrical configuration and arrangement of the apertures in my preferred forms of constructional elements enable me to employ, in the various types of joints described, a greater number of fasteners in bearing than has hitherto been possible with any known form of constructional element. In the joint shown in FIG. 20, for example, I can insert a total of eight bolts in bearing (as illustrated by the cross-hatched circles), no fewer than five of these being received in round apertures in both flanges. If desired an additional four bolts in friction could be inserted in the quatrefoils of the vertical element.
This is considerably better than anything which can be achieved with any known design of constructional element of this type. It should be particularly noted that with my arrangement, where bolts as described as being "in bearing", they are in bearing both vertically and horizontally, and in contrast to some known arrangements do not simply offer bearing resistance to downwards vertical loads.
While it is preferred to employ circular holes in the rows of apertures, it will be appreciated that this is not essential. In place of the circular holes other forms could be used while still retaining some of the advantages of my invention. For example square holes having a side equal to the dimension of the bolt or fastener to be used, could be employed. Additionally some advantage of my invention could be gained by employing elements having apertures of the type described in only one of the two flanges, the other flange being left unperforated, or having an arrangement of apertures other than those described.
Furthermore it will be evident that, although I have described and illustrated elements having rows of apertures extending uniformly throughout their lengths, it would be possible to arrange the apertures in shorter rows at only selected locations in the length of an element. | A constructional element of constant L-shaped cross-section formed by two metal flanges joined together at right angles has in each flange at least one row of regularly-spaced apertures extending longitudinally thereof. Each row comprises alternate circular apertures and non-circular apertures, the latter being elongated both parallel to and transversely to the length of the element. The rows of apertures in the flanges closest to the junction are offset with respect to each other so that the circular holes in one row register transversely with the non-circular holes in the other row. By the provision of non-circular apertures elongated in two directions, the versatility of the element when used in the fabrication of structural units and frameworks is enhanced. | 0 |
TECHNICAL FIELD
The present invention relates to electric irons for thermal shaping and styling of hair, and particularly irons with a timer for indicating treatment time to the user.
BACKGROUND OF THE INVENTION
Hair styling irons having an electrically heated elongate tool are well-known, and commonly used for curling or straightening hair. One of the challenges facing the users of such appliances, particularly for professionals, is how to most efficiently achieve a desired styling effect. A number of factors influence the effectiveness of heat to shape the hair, these include intrinsic properties of an individual's hair, treatments agents applied to the hair (such as water or other softening agents), the time and temperature of the heat application, as well as the manner in which the hair iron is used (the size of a tress which is treated, the tension applied to the hair etc). Consistent results can be obtained most efficiently if these factors can be kept relatively constant for a specific treatment or if, for instance, they can be varied incrementally to provide a different level of treatment, however in the past this has been somewhat problematic. In particular, processing results can be variable if the operation is performed too fast, the processing time is too short and, therefore, the hair is not properly formatted, while processing hair for too long can damage the hair by overheating.
To address these issues it is known to provide hair curling irons with a timer to indicate an elapsed time from the start of the timer. US2006/0191888 describes a hair iron in which time and temperature are coordinated, and in which the user selects settings for the iron temperature and a desired curl tightness. The elapsed time is controlled such that for a selected curl tightness, the elapsed time is decreased with increasing temperature. However, there are drawbacks with this device associated with its ease of use. In operation, it requires the user to remember to start the timer by pressing a start button each time the iron is used, and for consistent results this button must be pressed at the same stage of the operation each time. Particularly when manipulating the iron behind the head it may be difficult to locate and press the start button. Moreover, programming the controller is a complex operation, in which three different buttons must also be operated to increase and decrease the settings for the timer. There is therefore a need for a hair styling iron having a timer which can be more readily used.
A further disadvantage of the curling iron of US2006/0191888 is that the coordination between time and temperature in this prior art manner takes no account of the mass of hair being curled, and the fact that the heat required increases with the mass of hear being curled. At any selected temperature a short tress is formatted more quickly than a longer tress, with the result that a short tress may be overheated, while a long tress is under-heated. There is a need for a hair styling iron having a timer which can mitigate this source of variability, to help users produce good results more predictably.
It is an object of the present invention to overcome or substantially ameliorate the above disadvantages or more generally to provide an improved electric hair styling iron.
DISCLOSURE OF THE INVENTION
In one aspect the invention provides a hair styling iron comprising:
a handle to which a barrel is mounted,
a heating element in the barrel;
a motorised means for moving the barrel;
a control circuit including a timer;
a drive switch which is user actuable and connected to the control circuit for controlling operation of the motorised means;
and wherein the control circuit monitors at least one change of state of the user-actuable drive switch to determine a starting time, and actuates a response after an elapsed time measured from the starting time.
By having the drive switch that operates the motorised means also serve to set a starting time, operation of the hair styling iron is simple for the user and component numbers can be reduced, while the ability to provide consistent hair styling results in a timely manner is improved. The response may comprise an alarm, particularly a tactile, audible or visual alarm disposed in the hair styling iron.
Preferably the motorised means comprises a rotary drive that rotates the barrel. Optionally the motorised means vibrates the barrel.
Preferably the rotary drive rotates the barrel in a first direction upon actuation of the drive switch, and the response initiated by the control circuit after the elapsed time comprises turning the barrel in a second direction, opposite to the first direction. Preferably the control circuit records a first angle of rotation in the first direction, and the barrel is driven in the second direction through a second angle that is proportional to the first angle. The second angle may be sufficient to loosen the hair from the barrel. The second angle may, for instance, be between 80 and 110 percent of the first angle to provide for the hair to be completely unwound from the barrel.
Preferably the drive switch provides on-off control of the motorised means and when turned on moves the barrel at a fixed rate. Optionally, the drive switch may provide for modulated control of the motorised means for moving the barrel at a variable, user-controlled rate, such as a rheostat type switch.
Preferably the drive switch is a momentary switch, the actuation of which must be maintained by the user in order to operate the motorised means. Preferably the drive switch is a push-to-make switch. The drive switch need not be a mechanical type in which the user presses on an operator or mechanism to move a contact, and instead sensor type switches having, for example, capacitive or optical sensing elements, could be used.
Either the actuation or the release of the drive switch may define the starting time. In one embodiment the change of state comprises the first actuation of the drive switch, and the control circuit actuates the tactile, audible or visual alarm after an elapsed time measured from the first actuation of the drive switch. In another embodiment the change of state comprises the release of the drive switch immediately following the first actuation of the drive switch, and the control circuit actuates the alarm after an elapsed time measured from the release of the drive switch.
The hair styling iron may operate either in a user-selected time mode or in an automatic time mode, or else it may operate selectively in either the user-selected time mode or in the automatic time mode. In the user-selected time mode the elapsed time is determined based upon user selections made before use, such as a timer setting or temperature setpoint. In the automatic time mode the control circuit calculates an elapsed time depending upon how the hair styling iron is actually used, to account for the amount of hair to be curled.
User-selected Time Mode
Preferably the control circuit further comprises timer setting means for allowing users to select one from a plurality of predetermined timer setting values, each associated with an elapsed time. Preferably the timer setting means comprises a timer setting switch connected to the control circuit.
Preferably the control circuit comprises a thermostat, and means for selecting one from a plurality of setpoint temperatures, and wherein each of the plurality of predetermined timer setting values is associated with both a respective elapsed time and a setpoint temperature.
Automatic Time Mode
Preferably the change of state comprises both the first actuation of the drive switch, and the release of the drive switch immediately following the first actuation of the drive switch, and the control circuit actuates the alarm after an elapsed time which is calculated by the control circuit in direct proportion to the angle of rotation of the barrel relative to the handle that occurs between the first actuation and the release of the drive switch.
If the rotary drive rotates the barrel at a constant speed when the drive switch is actuated, the angle of rotation of the barrel is directly proportional to the time between actuation and release of the drive switch, so the control circuit may monitor the switch-operating time between the actuation and release of the drive switch and calculate an elapsed time in direct proportion to the switch-operating time. In this way the elapsed time may be determined in proportion to the length of hair wound onto the barrel during operation of the drive switch.
Where the drive switch provides for modulated control of the rotary drive then the control circuit may include a rotary encoder for measuring the angle of rotation of the barrel or, for example, the angular speed of the barrel could be integrated by the controller to calculate the angle of rotation of the barrel.
Preferably the control circuit comprises a thermostat, and means for selecting one from a plurality of setpoint temperatures, and wherein the elapsed time which is calculated by the control circuit is varied in proportion to the setpoint temperature.
Preferably, if the motorised means vibrates the barrel, then the control circuit may stop the motorised means to provide the alarm. If the motorised means rotates the barrel the control circuit may rapidly reverse the motorised means to vibrate the barrel and thereby provide the alarm. The hair styling iron may include an alarm signal generator, such as a wireless alarm signal generator, for transmitting an alarm signal to a remote tactile, audible or visual alarm. However, preferably the control circuit includes a separate vibrator, audio emitter or a light source to provide the alarm after the elapsed time.
Preferably a display is connected to the control circuit. The display may indicate a user-selected temperature and/or a user selected timer setting.
The control circuit may operate the alarm to provide a preliminary tactile, audible or visual alarm immediately before the elapsed time. For instance, the preliminary alarm may comprise two temporally spaced activations of the indicator for relatively short discrete lengths of time, before operating for a relatively long length of time upon expiry of the elapsed time.
Preferably the alarm is a vibro-tactile device, for instance a rotary motor with an eccentrically mounted weight disposed in the handle for vibrating the handle.
Preferably the timer-setting switch comprises a single-pole, single-throw instantaneous contact switch mounted to the handle and it is operable to toggle through a set of timer settings.
In another aspect the invention provides a hair styling iron comprising:
a handle to which a barrel is mounted,
a heating element in the barrel;
a clamp for urging hair into contact with the barrel;
a motorised means for rotating the barrel;
a control circuit including a timer;
a drive switch connected to the control circuit which is actuated by closing the clamp to urge the hair against the barrel;
and wherein the control circuit monitors at least one change of state of the drive switch to determine a starting time, and actuates a response after an elapsed time measured from the starting time.
In yet another aspect the invention comprises a method of curling air using a hair styling iron substantially as described above, comprising:
a) heating the barrel;
b) wrapping a tress around the barrel;
c) actuating the drive switch to wind the tress about the barrel,
d) releasing the drive switch to stop the rotary drive, and
e) awaiting an automatically generated alarm indicating the end of the elapsed time before removing the tress from the barrel.
The method may further comprise the step, prior to step c), of selecting one from a plurality of predetermined timer setting values, each associated with an elapsed time.
The method may further comprise the step of actuating a single button on the hair iron to select either (i) one from a plurality of predetermined timer setting values or (ii) an automatic time mode in which the elapsed time is calculated by the control circuit in direct proportion to the angle of rotation of the barrel relative to the handle that occurs between the first actuation and the release of the drive switch.
The method may further comprise the step, prior to step c), of selecting one from a plurality of setpoint temperatures, each of which defines a respective elapsed time.
The method may further comprise the step, prior to step c), of clamping the tress to the barrel.
Preferably the starting time coincides with the release of the drive switch.
In another aspect the invention provides a method of curling air using a hair styling iron as described above, comprising:
a) heating the barrel;
b) wrapping a tress around the barrel;
c) actuating the drive switch to wind the tress about the barrel in a first direction,
d) releasing the drive switch to stop the rotary drive,
e) receiving an automatically generated signal indicating the end of the elapsed time, and reversing the motorised means, in response to the automatically generated signal, to turn the barrel in a second opposing direction to unwind the tress from the barrel.
This invention provides a hair styling iron device and method which, by allowing a user to time a particular styling process in a simple manner, allows for more consistent styling results to be produced more efficiently. It will be understood that the invention may comprise any combination of the above-described features and is not limited to the specific features claimed according to the claim dependencies.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:
FIG. 1 is a partially cut away side view of a hair styling iron according to the invention;
FIG. 2 is a fragmentary internal view of the hair styling iron of FIG. 1 , and
FIG. 3 is a block diagram of a control circuit of the hair styling iron of FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 illustrate a hair styling iron according to the invention, which generally includes a curling spindle 10 and an elongate, hollow handle 14 . The spindle 10 is turned by a DC gear motor 12 and includes an elongated, generally cylindrical curling barrel 16 that extends generally coaxially from one end the handle 14 . The curling barrel 16 includes an electrical heating element 22 disposed in the curling barrel 16 . A clamping member 18 may be an elongated element pivotably attached to the curling barrel 16 by a transverse pivot 20 , and with a concave inner face generally complementary to the outer face of the curling barrel 16 . The clamping member 18 may be biased by a spring (not shown) toward the barrel 16 . A lever 24 may be fixed to the clamping member 18 for moving the clamping member between an open and closed position to enable retention and release of a strand of hair thereby.
Both the curling barrel 16 and handle 14 are hollow. The barrel 16 may have a plain surface, or may have other hair-engaging features such as protrusions, ribs, tines or bristles. The handle encloses a printed circuit board 26 to which the principal components of a control circuit 128 are disposed. The handle portion 14 of the styling iron 10 may be provided with a power cable 15 via which the control circuit 128 receives power. The control circuit 128 supplies current to the element 22 , controlling the current according to the setpoint temperature level at which the curling barrel 16 is maintained and that is set by a thermostat switch 28 . Thermostat switch 28 for setting the temperature may be an instantaneous contact type, operated as by individual actuations and releases stepping through a set of predefined temperature settings.
The control circuit further includes a rotational control switch 30 for initiating and terminating rotation of the spindle 10 in a selected direction 12 ; and a timer setting switch 32 for controlling timer operation. A display 124 may be connected to the control circuit 128 for indicating a user-selected setting (e.g. temperature, time, or the like). The display 124 may be active, including a light source such as a light emitting diode or the like, or it may be a passive display requiring outside illumination. The rotational control switch 30 may be an instantaneous reversing switch (double-pole, double-throw) which must be maintained actuated to operate the motor 12 . The timer setting switch 32 may be an instantaneous contact type, operated as by individual actuations and releases stepping through a set of predefined settings shown on the display 124 . A button (not shown) may make it possible to adjust the rotation speed of the spindle 10
A vibro-tactile indicator 36 may be employed to provide a response in the form of tactile alarm at the end of the elapsed time measured from a starting time. The vibro-tactile indicator 50 may comprise a motorised eccentric-type vibrator fixed inside the handle, such that the user is able to sense vibration of the handle 14 after the elapsed time. The vibro-tactile indicator 50 may be driven continuously or discontinuously to provide an alarm to indicate the elapsed time.
A main controller 38 is operatively connected to the display 124 , the rotational control switch 30 , thermostat switch 28 and timer-setting switch 48 . Also connected to the main controller 38 are a motor controller 40 , timer controller 42 and temperature controller 44 for respectively controlling the motor 12 , vibro-tactile indicator 36 and heating element 22 .
In operation of the styling iron, after connection to a power supply the thermostat switch 28 can be adjusted to select an appropriate temperature, typically a high, medium or low level. In a first embodiment the timer setting switch 32 is present, and allows the user to select one of, for instance, three timer settings for short, medium and long time, each defining a respective elapsed time. In a second embodiment the timer setting switch 32 may be present or absent. If present, timer setting switch 32 may allow a user to select between two modes: a first user-selected mode providing for selection of an elapsed time between predefined timer settings and a second automatic mode in which the elapsed time is determined automatically. If the timer setting switch 32 is absent, the elapsed time is determined automatically by the control circuit 128 .
In order to curl hair, the clamp actuating lever 24 is depressed so as to open the clamping member 18 . A portion of a tress is inserted beneath the clamping element and the lever is released so as to retain the strand of hair. The rotational control switch 30 is then activated so as to rotate the spindle 12 to wind the hair thereabout and then released when the desired length of hair has been wound up. Any one of these actions may serve to start the timer automatically. For instance, a switch (not shown) actuated by movement of the clamping member 18 toward the barrel 16 may send a starting time signal to the timer controller 42 . However, preferably the timer is started automatically by the main controller 38 monitoring a change of state of the rotational control switch 30 . When the main controller 38 identifies the release of the rotational control switch 30 immediately following the first actuation of the rotational control switch 30 , the controller sends a starting time signal to the timer controller 42 to define the starting time.
In the user-selected time mode, the timer is started automatically as by monitoring a change of state of the rotational control switch 30 . When the timer controller 42 receives the starting time signal a countdown is initiated and runs for an elapsed time associated with the timer setting selected by the user, before sending an actuation signal to generate a response, such as an alarm provided by the vibro-tactile indicator 36 at the end of the elapsed time. In this user-selected time mode the timer setting alone may not define the elapsed time. The elapsed time may be determined by the control circuit based upon both the timer setting and the setpoint temperature. For instance, for any one timer setting, a low setpoint temperature may be associated with a longer elapsed time than a high setpoint temperature.
In the automatic time mode, the elapsed time is varied to account for the length of hair wound about the curling barrel 16 . The rotary gear motor 12 may rotate the barrel 16 at a constant speed when the rotational control switch 30 is actuated, so that the angle of rotation of the barrel 16 is thus directly proportional to the time between actuation and release of the rotational control switch 30 . The motor controller 40 monitors the time between the actuation and release of the rotational control switch 30 during which time the motor 12 is operated and sends a feedback signal to the timer controller 42 which is indicative of the angular rotation of the barrel 16 during the time the motor 12 is operated. The timer controller 42 then calculates an elapsed time in direct proportion this switch-operating time. When the main controller 38 identifies the release of the rotational control switch 30 immediately following the first actuation of the rotational control switch 30 , the controller sends a starting time signal to the timer controller 42 to define the starting time. Starting from the calculated elapsed time a countdown is initiated before sending an actuation signal to generate a response, such as an alarm provided by the vibro-tactile indicator 36 at the end of the elapsed time. By controlling the elapsed time for the timer and starting the timer in this manner the appropriate curling time can be indicated to the user, and increased in accordance with the mass of hair that is being curled.
In the automatic time mode, the elapsed time may also be varied to account for the setpoint temperature. As shown in FIG. 3 , the timer controller 42 receives feedback from the temperature controller 44 for this purpose. The timer controller 42 varies the calculated elapsed time in direct proportion to the setpoint temperature. At a high setpoint temperature the calculated elapsed time is reduced, compared to that determined for a low setpoint temperature.
After the elapsed time, the user is prompted by the vibro-tactile indicator 36 to press the rotational control switch 30 to reverse the direction in which the spindle 12 rotates so as to unwind the hair therefrom; the rotational control switch 30 is released to terminate rotation, and the clamp actuating lever is depressed so as to release the now curled strand of hair.
In both embodiments and in both the user-selected time mode and automatic time mode the rotary drive may rotate the barrel in a first direction upon actuation of the drive switch, and the response initiated by the control circuit after the elapsed time may comprise turning the barrel in a second direction, opposite to the first direction. In this manner, once the hair has been heat treated for the elapsed time the response provides that the hair is loosened or completely unwound from the barrel automatically. No user intervention is required to loosen or unwind the hair from the barrel. While the alarm preferably accompanies the automatic unwinding of the hair, the alarm is not needed to indicate the elapsed time to the user, as the reverse rotation of the barrel itself indicates to the user that the elapsed time has passed. Thus the alarm is not essential to all embodiments of the invention. The essential feature is generation of some automatic response at the end of the elapsed time, such as an alarm or the reverse rotation of the barrel, which indicates the end of the elapsed time.
It will also be understood that the manner in which the hair is unwound is not essential to the invention, and for instance the spindle 12 may simply be disengaged from the gear motor at the end of the curling time via a clutch (not shown) which is operated by the control circuit to provide the response and to allow the spindle to rotate freely, thereby unwinding the curled hair. Such a clutch may also provide torque limiting for optimal tensioning of the hair as it is wound or for safety. An energy storage device such as a spring may be energised by the motor during winding up of the hair and then released by the control circuit at the end of the elapsed time, together with the clutch, to unwind the hair.
Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof. | A hair styling iron has a handle to which a heated barrel is mounted and a motor for moving the barrel. The iron includes a drive switch which is user actuable and connected to the control circuit for controlling operation of the motor. The control circuit includes a timer and monitors at least one change of state of the user-actuable drive switch to determine a starting time, and actuates an alarm, or another response, such as a reversal of the motor to unwind the hair, after an elapsed time measured from the starting time. The elapsed time may be user-selected or calculated automatically depending upon the length of hair wound onto the barrel, with compensation for barrel temperature. | 0 |
BACKGROUND OF THE INVENTION
The present invention pertains to the field of mobile elevationally adjustable folding stages, and to improvements therein. Stages generally of this type have come into wide-spread use in schools, hotels, convention centers, and other institutions wherein multiple use facilities require the capability of setting up a temporary stage. Such stages are made up of a number of individual sections which are positioned adjacent each other to make an extended stage surface of whatever size is required. When not in use, the individual sections may be folded to compact dimensions, then set aside for storage. Most such stages are made up of at least two stage surface members hinged together to allow the folding action, and have legs which are also pivoted to either fold out of the way or to remain in floor contact position while the stage surfaces fold to the stage position. Often wheels are provided to make the stage section mobile, so that it can be more easily transported from the use area to a storage area.
Elevationally adjustable folding stages have recently been developed to further increase the utility of the folding stage concept. Examples of such developments Wilson; U.S. Pat. No. 4,026,221 invented by Kermit H. Wilson, Richard C. Bue and Donald R. Carlson; U.S. Pat. No. 4,054,096 invented by Kermit H. Wilson, Ronald R. Carlson, and Richard C. Bue; and U.S. Pat. No. 4,074,636 invented by Kermit Wilson. Although the stages developed to date have been very successful in achieving their object of providing efficient and useful stages, further improvements are still possible, particularly with regard to stages having a very high maximum height, and also in regard to improving the convenience and efficiency in setting up the stage for use.
With regard to the maximum height of the stage, some designs which perform very well in small stages, or ones with a limited range of elevational adjustment, do not readily lend themselves to larger or higher stages, in part because of the need for increased rigidity to prevent swaying or shaking in a tall stage section. Of course all parts can be proportionately strengthened, but the resulting structure is not necessarily the most efficient in terms of weight, cost and difficulty of handling. The present invention provides a stage which is especially advantageous in stages of great height and load carrying capability, although it is equally well adapted for smaller stages.
The height adjustments in elevationally adjustable stages have proven to be difficult to handle for one person. Prior locking mechanisms for locking telescoping legs at a height have required elimination of the downward force of the stage to release a support pin. Each leg requires a support pin that must be released one at a time which may be difficult to do while relieving the downward force as oftentimes the legs are not within reach of one another, and increasing the time and effort required.
Prior folding mechanisms in folding stages have shown that further improvements are possible in releasing and latching stage surface members. The prior stages have demonstrated a need for lift and fold assistance which minimizes the effort required by a person folding the stage or adjusting the height of the stage. An easy way of locking and releasing both height adjusting pins of a stage surface member from a single remote location is needed.
The present invention addresses these problems associated with folding stages. It is apparent that an improved mechanism and method for folding and elevationally adjusting stages is needed. The present invention solves these problems and others associated with folding stages.
SUMMARY OF THE INVENTION
The present invention relates to elevationally adjustable folding stages, and to improvements in folding and lifting of the stages. Two stage surface members are hingable connected along a center line between the two members. In an operation position, the stage surface members form a substantially planar stage surface. When folded, the stage surface members are in a substantially vertical position wherein the undersides of the stage surface members oppose one another. The stage has two support legs for each of the stage surface members and may have folding wheels so the stage can be easily moved. The folding stage has support braces which are adjustable to provide support for the stage members at different heights in an operation position. The braces are adjustable so that they release when the stage members are moved from an operation to a folded position and back to the operation position. The braces are also provided with cross supports which are releasably lockable for adjusting to different elevations. In this respect the elevation of the stage can be adjusted and the stage still provides adequate bracing.
The support legs are elevationally adjusted by having telescoping inner legs extending from the main support legs. Pins insert into holes in the inner telescoping leg and the outer legs for maintaining the stage at a designated elevation. In the operation position, adjustments are made by releasing the pin from each leg of a stage surface member and raising each stage surface member to the desired elevation, the pins are then reinserted for supporting the main support legs relative to the telescoping legs. The pins are connected to a remote releasing mechanism so that both pins for a stage surface member are actuated at a remote location at the edge of the underside of the stage surface member. A sliding handle, which can be gripped while holding the edge of the stage surface member, is pulled toward the edge of the stage surface member to release both pins. In this manner the pins are released by holding to the underside of the edge of the stage surface member and lifting while holding the handle out. When the stage is at the desired height, the handle is released while still holding on to the underside of the edge of the stage surface member so that the resiliently biased pins insert into the desired height adjustment holes.
Lifting is aided by lifting assist means connecting to a lower cross member between the main support legs, and to the underside of the corresponding stage surface member. With the aid of the lifting assist means, raising and lowering the stage requires less effort so that one person can easily lift the stage. A hinge plate, pivotally attached to the upper portion of the lifting assist means and to the stage surface member, allows folding while still providing adequate lifting assistance. The lifting assist means in conjunction with the remote releasing linkage provides for one-person-lifting of the stage. While holding the handle of the releasing mechanism in the release position, a person pushes up or allows the stage surface member to be lowered with the aid of the lifting assist means. When at the desired location, the elevational adjusting mechanism is released so that the pins are placed back in the provided height adjustment holes. The lifting assist means provide enough lifting force so that one person can easily raise and lower the stage surface members. When one side has been raised or lowered, the other side is done in a similar fashion to provide a level stage surface.
Folding of the stage is accomplished by actuating a center handle for lifting the stage surface members and an accompanying folding mechanism into a folded position. The folding handle is attached to a latching mechanism for releasing the stage surface members for folding and includes a latch mechanism for locking the stage surface members in the operation position. The handle extends slightly outward from a side of the stage surface members along a center hinge. By pushing upward on the handle the latch is disengaged from the locked operation position and upward movement of the handle moves the stage surface member to the folded position. The latching mechanism includes a contoured cam engaging a finger on a center member extending from the handle. When the stage surface members are retracted to the fully folded position a side locking arm is swung from the edge of one stage surface member to the other for latching the stage in the folded position. For unfolding, the side locking arm is unlatched and the stage surface members are pulled downward. The center member is spring-loaded so the finger engages the cam of the latching mechanism and guides the member towards the latched position. When reaching the latching position, the member is moved into the locked position wherein an end portion of the member inserts into a hole in a center hinge member, providing additional bracing. Folding is made easier as the lifting assist means provide mechanical advantage in folding the stage as well as lifting.
The support legs and the folding and elevational adjusting mechanisms are positioned within the stage area so that in the operation position, the stage may abut adjacent stages to form a continuous large stage surface. The stage sections include male and female locking members for aligning the adjacent stage sections and positioning them for a continuous stage surface.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings wherein like reference numerals and letters indicate corresponding elements throughout the several views:
FIG. 1 is a perspective view of an elevationally adjustable folding stage according to the present invention, shown in its unfolded operative position;
FIG. 2 is a perspective view of the stage of FIG. in its folded position;
FIG. 3 is a front elevational view of the stage of FIG. 1 in its operative position with different heights shown in phantom;
FIG. 4 is a right side elevational view of the stage of FIG. 1 in its operative position;
FIG. 5 is a bottom plan view of the stage of FIG. 1 in its operative position;
FIG. 6 is a detail of the lock releasing mechanism for the stage of FIG. 1;
FIG. 7 is a detail of the underside of a stage surface member of the stage of FIG. 1;
FIG. 8 is a bottom detail of folding mechanism of the stage of FIG. 1 in its latched position;
FIG. 9 is a perspective view of the handle of the folding mechanism of FIG. 8 in a partially folded position;
FIG. 10 is a perspective view of the spring portion of the folding mechanism of FIG. 8 in its latched position;
FIG. 11 is a side perspective view of the folding mechanism of FIG. 8 in an unfolded position;
FIG. 12 is a side perspective view of the folding mechanism of FIG. 8 in a partially folded position;
FIG. 13 is a perspective view of the latch portion of the folding of FIG. 8;
FIG. 14 is a side view of a detail of lift assist mechanisms of the stage of FIG. 1 in a folded position; and
FIG. 15 is a perspective view of a detail of the lift assist mechanism of FIG. 14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The overall configuration of the stage according to the present invention is best seen in FIG. 1, which generally shows a stage 30 in its unfolded or operative position, and FIG. 2, which shows the stage 30 in its folded or storage position. The stage 30 comprises a pair of stage surface members 32 and 34. Each stage surface member is a generally rectangular planar member which may be made of any suitable material. The stage surface members 32 and 34 are reversible so that a different top surface may be obtained by having the opposite side with a different surface facing up. Each of the stage surface members 32 and 34 is reinforced underneath by a reinforcing frame made up of a number of pieces of welded iron rails. As seen in FIG. 5, member 32 has side reinforcing rails 36 and 38, while member 34 similarly has side rails 40 and 42. Member 32 has end rails 44 and 46, while member 34 has corresponding end rails 50 and 52. Each stage surface member has an intermediate cross rail 48 and 49 respectively and a pair of intermediately positioned transverse reinforcing rails 54a and 54 b, and 56a and 56b, respectively.
The reinforcing rails described above are welded together to form a rigid supporting frame for each stage surface member, which may then be bolted or otherwise attached to its respective base frame. It can be appreciated that a number of framework arrangements may be used which provide adequate bracing yet allows folding. The reinforcing base frame also serves as convenient attachment points for the legs, hinges and other hardware items as hereinafter described.
As shown in FIGS. 3 and 4, the outer edges of the stage surface members 32 and 34 have interlock members attached thereto. The members include male members 190 which lock with female members 192 of an adjacent stage to form a large planar surface.
The stage surface members 32 and 34 are hingably connected to each other along one edge by means of hinge assemblies. As shown in FIGS. 3, 5, and 9-13, three center hinge assemblies provide bracing and guide the stage surface members 32 and 34 during folding. The hinge assemblies have links 176a, 176b, and 176c attaching to stage surface member 32, and similarly links 178a, 178b, and 178c, attaching to stage surface member 34. The corresponding links attach at center pivots 180a, 180b, and 180c, respectively. The center pivots 180a, 180band 180c also connect to center links 182a, 182b, 182c, and 184a, 184b, 184c, respectively. Center links 182a, 182b, and 182c rigidly attach to the underside of stage surface member 32 along the center edge, similarly center links 184a, 184b, and 184c attach to stage surface member 34. With this arrangement, the stage surface members 32 and 34 are hinged about pivots 180a, 180b, and 180c during folding. The stage surface members are adjusted relative to one another by spacing bolt 186 shown in FIG. 11. The spacing bolt 186 can be adjusted to increase and decrease the spacing of the stage surface members along the center hinge.
As shown in FIG. 1, a pair of hinge plates 66a and 66b are welded to rail 48, and a pair of similar hinge plates 68a and 68b are welded to rail 49 of stage surface member 34. The corresponding hinge plates 66 and 68 are spaced opposite each other but offset slightly so as to overlap. The hinge plates 66 and 68 pivotally attach to the support frame and permit relative movement of the stage surface members 32 and 34 and the support legs 76 and 78 between a compact folded or storage position as indicated in FIG. 2, in which the stage surface members 32 and 34 are generally vertically oriented, and an unfolded or operative horizontal position as indicated in FIG. 1 in which the stage surface members 32 and 34 are horizontal and define a continuous stage surface.
Each of the stage surface members 32 and 34 has a pair of main support legs. For the stage surface member 32, the main support legs comprise a leg 76a and a corresponding leg 76b on the other side as seen in FIG. 1. Similarly, stage surface member 34 has main support legs 78a and 78b. The main support legs may be made for convenience from square metal tubing, as is more clearly seen for example in FIG. 7. Each of the pairs of main support legs 76a, 76b, and 78a, 78b are interconnected by a cross brace, such as brace 94 in FIG. 1, at the lower portion of the main support legs. Each brace 94 is pivotally attached to a wheel mechanism 98. The wheel mechanism 94 is rotated to a rolling position to support the stage 30 for mobility. An upper cross brace 96 and intermediate brace 95 are also provided between the legs of each pair of main support legs.
Each of the main support legs is hingeably connected to reinforcing rails underneath their respective stage surface members. Referring specifically to FIG. 5, additional reinforcing rails 100 and 102 are positioned adjacent rails 36 and 38, respectively, beneath member 32. Similarly, reinforcing rails 104 and 106 are positioned adjacent rails 40 and 42, respectively, beneath stage surface member 34. The leg 78a pivots about a pivot bolt (not shown). A construction similar to that just described exists with respect to each of the other three main support legs.
Referring to FIGS. 1 and 3, a plurality of cross connect links are seen interconnecting the stage surface members to the main support legs of the opposite stage surface member. Cross connect links 108a and 108b are connected by pivots to the lower portions of main support legs 76a and 76b; link 108a is connected by pivot 110a, and link 108b is connected by a similar pivot (not shown). In a similar manner cross connect links 116a and 116b connect to pivots 111a and 111b, respectively. The upper ends of links 108a and 108b are attached by means of pivots 112a and 112b to cross connect links 120a and 120b respectively. Pivots 112a and 112b are adjustable and may be loosened for adjustment by loosening a set pin 121. Similarly, the upper ends of cross connect links 116a and 116b connect by means of pivots 114a and a similar pivot (not shown) to cross connect links 122a and 122b respectively. The lower ends of links 120a and 120b connect by means of pivots 118a and a similar pivot (not shown) to the horizontal brace 95 which interconnects the main support legs 78a and 78b. In similar fashion, the lower ends of cross connect links 122a and 122b connect by means of pivots 124a and 124b to cross brace 95 which interconnects main support legs 76a and 76b. The upper end of cross connect links 120 and 120b connect at pivots 70a and 70b of hinge plates 66a and 66b, respectively. In a similar manner, cross connect links 122a and 122b connect at pivots 72a and 72b of hinge plates 68a and 68b respectively. The main support legs 76a and 76b are elevationally adjustable by raising or lowering the legs 76a and 76b, and 78a and 78b relative to telescoping inner legs 80a and 80b, and 82a and 82b, respectively. As shown in FIG. 6, pins 128 insert into the main support leg and the telescoping leg to adjust the height of the stage.
Elevational adjustment pins 128 are released at a remote location in a preferred embodiment. As shown in FIG. 6, release mechanism 126 is connected to pin 128 and to the corresponding pin (not shown) on the corresponding leg for each stage surface member so that both pins 128 may be removed during elevational adjustment from a single remote location. The release mechanism 126 is actuated from a single sliding handle 130 at a location near the edge of the stage surface member 32 or 34. With this arrangement, the sliding handle 130 may be actuated while at the same time lifting on the edge of the stage surface member 32 or 34.
With the aid of lift mechanism 136, the stage 30 is elevationally adjusted by gripping an edge of the stage surface member, grasping the handle 130 to release the pins 128, and lifting or lowering the associated stage surface member. The release mechanism 126 has horizontal handle 130 sliding parallel to the stage surface member. The handle 130 is hingeably connected to intermediate member 132. The intermediate member 132 hingeably connects to pins 128 at the end opposite the sliding handle 130. The intermediate member 132 pivots about an intermediate pivot 134 on the main support leg so that sliding the handle 130 toward the edge of the stage surface member moves the upper end of the intermediate member 132 toward the edge of the stage surface member and pivots the opposite end toward the center of the stage, releasing the pins 128. The pins 128 are biased toward an inserted position by an expansion spring 129. The spring 129 resiliently engages a flange or washer 131 of pin 128 to insert the pin 128 into the main support leg and telescoping leg. The intermediate member 132 is bent around the main support leg 78a at the top end, as shown in FIG. 7, so that the leg does not limit the motion of the intermediate member 132. The intermediate members 132 bend around the other legs in a similar manner.
As shown in FIGS. 3, 14 and 15, lift mechanisms 136 are used to aid in elevational adjustments. The lift mechanisms 136 include lift members 138 hingeably attached to leg cross members 94, and to hinge plates 140. In the preferred embodiment, each lift mechanism 136 utilizes a pair of gas springs (not shown) mounted within lift member 132. The gas springs are mounted end to end within the lift member to provide greater expansion and contraction and thus greater elevational adjustment. Additional lift and bracing are provided by similar additional gas springs 188 attached to brace 96 and the underside of the corresponding stage surface member. In the preferred embodiment, the gas springs are sized so that the lifting force required of a worker is minimized.
As shown in FIGS. 14 and 15, the lift members 138 attach to the hinge plates 140 to provide for pivoting the lift mechanisms 136 to the folded position. The hinge plates 140 are formed of two plates attached by bolts to the rails 54a and 54b, respectively. Bolt 142 forms a stop against the rail to limit movement of the hinge plate 140 as shown in FIG. 15. The hinge plates 140 pivot to a position for folding and is stopped by member 144. Lift members 138 extend and contract during folding to provide for movement between an operation position and a folded position.
Referring now to FIGS. 8-13, folding mechanism 150 is shown for locking the stage 30 in an operating position. As shown in FIG. 9, the folding mechanism 150 utilizes handle 152 for actuating the mechanism 150 to lock and release the stage surface members. The handle attaches to links 154 and 156 at pivot 158. The link 156 attaches to pivot 160 on tab 162 attached to the underside of the stage surface member 32. The link 154 attaches to member 164 which extends to the latching mechanism.
As shown in FIG. 10, the member 164 has an extension 166 which engages spring 168 so that the member 164 is under tension and pulled inward toward the center of the stage 30. In this manner, finger 170 projecting from member 164 is pulled against cam 172 as shown in FIGS. 8 and 12. The cam 172 is shaped so that it widens as the finger 170 is moved toward a locking position. With the spring 168 providing pressure to the finger 170 against the cam 172, the stage will not slip down from an unfolded position. The spring 168 pulls the member 164 inward so that the finger 170 is pulled into a locking position when passing the corner of the cam 172 as shown in FIG. 13. In this manner,, rod 174 extending from member 164 is forced into hole 175 in the locked operative position and provides added bracing and safety to the stage 30. To unlock the latch and remove rod 174 and finger 170 from the locked position, the handle 152 is pulled upward to a release position. The handle 152 is used to lift and pull the stage 30 into the folded position shown in FIG. 2. A side locking arm 177 is then swung into a locked position and hooked to a pin (not shown) to prevent the stage 30 from unfolding.
It can be seen then, that the present invention provides a folding stage having an improved folding and latching mechanism. The present invention also provides a remote locking and releasing mechanism for easier elevational adjusting of the stage. With lifting assist means, easy single person elevational adjustment and folding are provided for with minimum effort.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. | An elevationally adjustable folding stage (30) has two stage surface members (32, 34) which form a planar stage surface. The stage surface members (32, 34) fold to substantially vertical storage position. The stage (30) includes elevationally adjustable telescoping legs (80, 82) which can be adjusted to a number of elevations. Height adjustment pins (128) are remotely released from a location that allows lifting of the stage while simultaneously releasing the height adjustment pins (128) for the corresponding stage surface member. Lifting is aided by lift mechanisms (136) to counter the weight of the stage (30). The stage surface members (32, 34) hinge at a center position and are latched and unlatched by a locking mechanism (150). The locking mechanism (150) uses a spring-loaded member (164) with a finger (170) engaging a cam (172) to guide the sections during folding and biasing a rod (174) to a locked position. | 4 |
The present invention relates to a method for supporting congestion management in a congestion exposure-enabled network, wherein sending hosts and receiving hosts communicate with each other by sending flows of packets over network paths via intermediate routers, which, upon detecting congestion, mark packets of said flows as congestion packets by including congestion information, wherein congestion is indicated to the sending hosts by means of a congestion feedback mechanism, and wherein the sending hosts, upon receiving congestion indications, declare a subset of the packets they send as congestion response packets by including congestion information, depending on whether the amount of congestion response packets is balanced with the indicated congestion level or not.
Furthermore, the present invention relates to a congestion exposure-enabled network system, said system comprising sending hosts, receiving hosts and intermediate routers, wherein said sending hosts and said receiving hosts communicate with each other by sending flows of packets over network paths via said intermediate routers, which, upon detecting congestion, mark packets of said flows as congestion packets by including congestion information, wherein a congestion feedback mechanism is provided being configured to indicate congestion to the sending hosts, and wherein the sending hosts, upon receiving congestion indications, declare a subset of the packets they send as congestion response packets by including congestion information, depending on whether the amount of congestion response packets is balanced with the indicated congestion level or not.
Finally, the present invention relates to an intermediate router for use in a congestion exposure-enabled network, wherein sending hosts and receiving hosts communicate with each other by sending flows of packets over network paths via said intermediate router, wherein, upon detecting congestion, said intermediate router is configured to mark packets of said flows as congestion packets by including congestion information, wherein a congestion feedback mechanism is provided being configured to indicate congestion to the sending hosts, and wherein the sending hosts, upon receiving congestion indications, declare a subset of the packets they send as congestion response packets by including congestion information, depending on whether the amount of congestion response packets is balanced with the indicated congestion level or not.
BACKGROUND OF THE INVENTION
Congestion-based network traffic policing based on congestion exposure is a promising network resource control paradigm that accounts for user traffic in the event of network congestion. It has been argued, for example in B. Briscoe, “Flow Rate Fairness: Dismantling a Religion”, ACM Computer Communications Review, 37(2), 63-74 (April 2007), that flow rate fairness, which has been used in the past, is not a reasonable mechanism for resource allocation and accountability of network resources. Instead, it is suggested that a cost-based mechanism would provide a better resource allocation paradigm, in which “cost” means the degree to which each user's transfers restrict other transfers, given the available network resources. The metric that has been suggested for measuring this cost is the volume of network congestion caused by each user. A network traffic policing mechanism based on congestion offers a net-neutral way for network operators to manage traffic on their networks.
There have been several proposals for implementing congestion-based network traffic policing. For example, Re-ECN (Relay or Re-feedback of Explicit Congestion Notification) is a proposal that has been made in the Internet Engineering Task Force (IETF) Congestion Exposure (CONEX) Working Group, being described, for example, in B. Briscoe, A. Jacquet, C. Di Cairano-Gilfedder, A. Salvatori, A. Soppera, and M. Koyabe, “Policing Congestion Response in an Internetwork using Re-feedback”, Proc. ACM SIGCOMM'05, CCR, 35(4):277-288, August 2005. As will be discussed in greater detail below, Re-ECN, or re-feedback of explicit congestion notification provides a feedback mechanism through which packets expose the congestion that they expect to cause. The key feature is the user based accountability that is not based on resource usage but on the congestion user traffic is causing to others in a network. It is important to note that Re-ECN is one way of doing Congestion Exposure mechanism and alternatives are also possible.
For instance, in a Re-ECN system as shown in FIG. 1 , which is a specific implementation of a congestion exposure system, there are different functional entities: routers detect congestion and apply Explicit Congestion Notification (ECN) to packets in their queue. Receiving endpoints collect this congestion information and relay it back to the sender. The sender runs a transport protocol (for instance TCP) and can use this information for the congestion control algorithm of a transport protocol. Also, the sender is expected to re-act to the received feedback declaring its contribution to congestion for subsequent packet transmissions. This is done by marking a certain fraction of packets appropriately. An operator-provided Congestion Exposure aware Policer can use this information to police or to account for traffic accordingly.
Thus, the Congestion Exposure approach is based on the idea that senders adapt to congestion indications from the network, for instance by decreasing TCP sending rates, and that senders declare their current congestion contribution to the network, which enables the network, e.g. routers, hosts, policers etc., to see the current congestion on a path. For instance, such information can be used to police traffic based on its congestion contribution according to some operator policy.
Since such policing can result in charging or other operator measures, users are normally not interested to over declare their current congestion contribution. In the Congestion Exposure framework, there are additional entities in form of an Audit Function that can enforce that congestion contribution is also not under declared in order to avoid non-conformity, e.g. cheating. In case non-conformity is detected, an Audit Function would normally start dropping packets of identified non-conformant flows to enforce a sending rate reduction for that particular flow. In summary, in Congestion Exposure, it is important for senders to declare their congestion contributions to the network correctly.
Furthermore, this approach does work in different scenarios, e.g. in fixed or mobile communication scenarios. For incorporating Congestion Exposure into mobile communication networks, a major challenge is to handle path changes caused by new network attachments. There are essentially two main issues:
Associating with a new wireless access point that changes the paths for current flows to/from a mobile node. The new paths may exhibit a lesser or greater congestion, but the current sending behavior and the current congestion declaration is based on earlier received feedback and may not match the new paths' conditions. In particular, if a mobile user moves to a higher congestion region, he may inadvertently create deficit at the egress Audit Function that in turn may classify that particular subset of traffic as non-conformant. When multiple access networks are available for a handover decision, the mobile node has currently no means to select the most optimal one with respect to average path congestion. Some mobility architectures base handover decision on current access point load, but that is not sufficient if the congestion is occurring at different locations in the path.
In view of the above, it is therefore an object of the present invention to improve and further develop a method of the initially described type for supporting congestion management in a congestion exposure-enabled network in such a way that, by employing mechanisms that are readily to implement, mobile users have an improved quality of experience in the context of handling path changes in events of mobility.
SUMMARY OF THE INVENTION
In accordance with the invention, the aforementioned object is accomplished by a method comprising the features of claim 1 . According to this claim, such a method is characterized in that aggregated congestion is determined on the basis of congestion information included in packets that are sent over said network paths between said sending hosts and said receiving hosts.
Furthermore, the aforementioned object is accomplished by a congestion exposure-enabled network system comprising the features of claim 17 . According to this claim, such a system is characterized in that said network system is further configured to determine aggregated congestion on the basis of congestion information included in packets that are sent over said network paths between said sending hosts and said receiving hosts.
Finally, the aforementioned object is accomplished by an intermediate router comprising the features of claim 18 . According to this claim, such an intermediate router is characterized in that said intermediate router is further configured to determine aggregated congestion on the basis of congestion information included in packets that are sent over said network paths via said intermediate router between said sending hosts and said receiving hosts.
According to the invention it has first been recognized that an improved quality of experience for mobile users in the context of handling path changes may be realized by considering exposed congestion information. Specifically, according to the invention, aggregated congestion is determined on the basis of exposed network path congestion information. That means, that aggregated congestion can be computed on the basis of congestion information included in data packets that are sent over a path between a sending host and a receiving host. Instead of looking at fine granularity of actual physical paths, congestion information available in data packets, e.g. in congestion packets and/or congestion response packets, is exploited and the congestion information is aggregated based on involved network elements, e.g. intermediate routers, on the path within an operator domain for either direction of traffic. Thus, by using the aggregated congestion mobile users can be assisted in such a way that a timely and safely adjusting congestion response at the end host in advance is enabled and therefore mobile users have a better quality of experience while being mobile. As a result, mobile nodes can be assisted in path changes especially in mobility events for optimizing quality of experience in mobile scenarios.
According to a preferred embodiment the aggregated congestion may be determined by calculating a fraction of congestion marked packets. For a single node, e.g. router, eNodeB, etc., an aggregation mechanism may be provided for calculating the fraction of congestion marked packets in the downlink direction.
Additionally or alternatively, the aggregated congestion may be determined by summing up a number of congestion marked packets over a predefined time period, in particular in the downlink direction.
Consequently, this coarse grain calculation may enable an overall estimate of congestion that a set of end hosts that may be designated as mobile nodes are experiencing in the downlink direction. The calculation is coarse grained since it is independent of application, communication partner, path, topology, etc. For the uplink direction, such a calculation may be delegated to a node towards the edge of the network, for example a gateway.
Advantageously, the congestion information may include Re-ECN-specific markings. Thus, the congestion information may be retrieved from data packets by looking at Re-ECN specified protocol fields.
In a preferred embodiment, it may be provided that a path congestion prediction regarding the expected congestion level on a path is derived from the aggregated congestion, in particular by calculating a path congestion prediction factor. Thus, mobile node response to congestion and handover decisions in the mobile communication network can be improved.
Advantageously, network-generated hints may be provided, wherein the hints include the path congestion prediction.
Furthermore, the network-generated hints may be disseminated to network elements and/or end hosts. Network elements include e.g. intermediate routers, access points or any node between two end hosts. Thus, congestion information can be spread within the network and to end hosts, e.g. mobile nodes that are using the network resources. Therefore, a better network utilization is enabled and a better performance by limiting congestion contribution by mobile users can be achieved.
With respect to improving quality of experience for mobile nodes that may be designated as end hosts, the network-generated hints may be employed for assisting the hosts in events of mobility, in particular during handover events. In the context of Congestion Exposure that is a congestion based policing mechanism where transport protocol instances can also take user preferences into account, a possible reaction when a mobile node enters a new cell and receives the network-generated hint that this cell is heavily congested, it might decide to not continuing with data traffic of a specific application starting from a configurable congestion level. For example in case the congestion hint is being larger than a threshold.
In an advantageous embodiment the network-generated hints may be employed for adjusting congestion response at the end hosts. A possible and relevant optimization of reacting on this hint mechanism is assisting mobile nodes for adjusting their congestion response when they are moving from one access point to another one. Through this systematic approach, information is provided to the mobile nodes about expected congestion levels before they actually send their first set of data packets. So based on that hint, the mobile nodes may decide to send more or less packets to the network and therefore more quickly adapt to the expected congestion level, before they actually start receiving congestion notifications from the receiver and therefore also might overload the network to a lesser extent. It is noted that the Audit Function functionality as foreseen in a Congestion Exposure environment maintains an invariant that congestion response packets should have an impact greater than that of congestion packets. So when the adaptation of a communication is too slow it might cause high number of drops and downgrade throughput heavily for the time until the end-system has adapted to the right level of sending rate.
Advantageously, the network-generated hints may be disseminated to mobility management entities in order to influence the mobility management decisions. For example, the hints may be used to decide about a particular attachment point. So the mobility management functionality, e.g. either in the mobile node in case of mobile IP based mobility schemes or at the 3GPP MME in 3GPP cases, may receive the hint about congestion level and may decide to move a mobile node or not to move, depending on that information. It is noted the difference to load based mobility management schemes, which try to optimize for getting equal load for a single component, whereas this proposed scheme tries to guess with a heuristic the congestion of all mobile nodes using different end-to-end paths in the network and takes therefore the overall situation into account and only reacts in case of congestion, but can also react on the different congestion levels.
Advantageously, the generation of the network-generated hints may be isolated among individual network elements, e.g. routers, for constructing a local congestion view indicating congestion between a subset of nodes on a path.
According to a preferred embodiment, the local congestion view may be represented as fraction.
According to a further preferred embodiment local congestion views for subsets along the path may be combined to generate a global congestion view in order to predict congestion for the complete path.
According to a still further preferred embodiment accuracy information regarding the computation of the network-generated hints may be signaled together with the hints.
Advantageously, the communication of the network-generated hints may be performed by exchanging the hints on the air interface of a network element, e.g. of an eNodeB, to the interface of a host, e.g. a mobile node.
Furthermore, it may be provided that the communication of the network-generated hints may be performed by employing ICMP (Internet Control Message Protocol) control messages.
BRIEF DESCRIPTION OF THE DRAWINGS
There are several ways how to design and further develop the teaching of the present invention in an advantageous way. To this end it is to be referred to the patent claims subordinate to patent claim 1 on the one hand and to the following explanation of preferred embodiments of the invention by way of example, illustrated by the figure on the other hand. In connection with the explanation of the preferred embodiments of the invention by the aid of the figure, generally preferred embodiments and further developments of the teaching will be explained. In the drawings
FIG. 1 shows an overview of a previously known Congestion Exposure framework,
FIG. 2 is a schematic view illustrating a path change due to handover events,
FIG. 3 is a schematic view illustrating an example of an application scenario of a method according to the present invention, and
FIG. 4 is a schematic view illustrating an example of another application scenario of a method according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows an overview of the Congestion Exposure framework, and its functional entities. Congestion Exposure is described, for example, in B. Briscoe, A. Jacquet, C. Di Cairano-Gilfedder, A. Salvatori, A. Soppera, and M. Koyabe, “Policing congestion response in an internetwork using re-feedback”, Proc. ACM SIGCOMM'05, CCR, 35(4):277-288, August 2005.
As shown in FIG. 1 , a sender 102 (e.g., a TCP sender) and a receiver 104 (e.g., a TCP receiver) communicate over a path that includes routers 106 , 108 , and 110 , as well as a policer 112 and an Audit Function 114 . For the sender 102 and the receiver 104 , the path can exhibit different characteristics with respect to delay, packet loss or “Congestion Experienced” (CE) marking rate due to transient or persistent congestion. Routers, such as the routers 106 , 108 , and 110 , implementing active queue management (AQM) mechanisms probabilistically set the explicit congestion notification (ECN) bits (using random early detection (RED)) in the IP packets, such as packets 122 indicated by the shaded rectangles, when they detect incipient congestion. The receiver 104 , upon receiving congestion marked packets, such as the packets 122 , notifies the sender about the current congestion level through its transport protocol's feedback mechanism, e.g., using TCP header fields. The sender 102 then reacts to received congestion indications by adapting the sending rate according to the congestion control mechanisms of the specific transport protocol, and by declaring a fraction of the IP traffic sent on this connection as its congestion contribution to the network, by placing re-echo information in packets sent, such as congestion response packets 120 indicated by the filled rectangles, with the goal of balancing the number of “negative” bytes, i.e. the congestion contribution as reported by congestion feedback, with the number of “positive” bytes, i.e. the congestion contribution response as declared by the sender.
Thus, the basic principle of Congestion Exposure is to re-insert information on the experienced congestion back into the network. This allows an ingress policer 112 to decide what a user is entitled to in terms of allowed congestion according to network policies. In contrast, an Audit Function 114 , which is implemented as packet dropper, validates what is being declared in correct or not and, as the case may be, drops packets in flows that persistently declare negative downstream congestion (i.e., that under-declare their congestion contribution).
Operators may choose to place the policer 112 at the network ingress, e.g., for rate-limiting the congestion that a user is allowed to cause in a given time period or for applying certain accounting schemes. Once a pre-configured quota is consumed, certain types of penalties are possible, e.g. imposing a decrease in service rate. It should be noted that the ingress policer 112 only rate limits the declared congestion. Therefore, there is still a possibility that understating the congestion may lead to a higher bit rate corresponding to an increase in utility. For the honest users, the response and congestion fractions should cancel out each other at the egress. It is not true for the users that are understating the congestion and their traffic eventually experiences a net deficit at the egress. Therefore, the Audit Function has been proposed to be the last entity in the path for penalizing the non-conformant flows.
Since traffic between hosts is bi-directional, after negotiating Congestion Exposure capability during connection setup each end point maintains a local 3-bit counter for recording CE events for that half of connection. The counter at the sender is designated as a local one whereas the one at the receiver is designated as the remote counter. The scheme is symmetric for the other half of connection. During congestion, the local counter at the receiver is incremented on each CE packet arrival. The receiving host updates the remote sender on the very next acknowledgement through its transport support. On each arrived acknowledgement, a sender compares its local counter value with the new value and records the difference. The difference is debit (congestion response packets 120 indicated by the filled rectangles) that a user owns traffic to the network.
In the context of Congestion Exposure, it is the responsibility of the transport protocol instance to adapt to changing path (network) conditions. Since Congestion Exposure should work with any transport protocol, the mechanism of path adaptability is orthogonal to any congestion control mechanism implemented at the end point.
Additionally for adjusting response, a transport protocol instance estimates two parameters from arriving acknowledgements:
Path congestion estimation Error Correction in response since congestion is not static, i.e. it changes dynamically.
Initially both congestion estimate and error correction are unknown to the sending host, therefore it can be safely stated that feedback state is stale. In stale state, a sender uses pre-credits in the forward path until it starts receiving acknowledgements on the back channel. Each acknowledgement carries congestion information that a receiver is recording. Further, it can be argued that after receiving e.g. “n” acknowledgements, sufficient knowledge about the path state is captured.
For window based transport like TCP, n=1 is a special case of the above generalization and state transition may be made with the very first arriving acknowledgement. Since TCP is “ack” driven, the path state can be tracked from so far received acknowledgements and then based on that estimate error correction in response can be applied. The motivation for error correction is twofold. First, there is a lag between forward and feedback channel which not necessarily cancel out congestion and response packets at egress. Moreover, path congestion is not stationary as recorded in the last round trip time (RTT); therefore the estimate at the sender has some error in it. For each send operation, a sender has an estimate of observed path congestion and based on that estimate it further estimates how much congestion it should expect when acknowledgements of those packets will arrive. The response packets are sent in one to one correspondence of CE packets. By keeping track of congestion window and post-credits issued so far, a sender ensures that it has sufficient balance in forward path for safely passing through the Audit Function at the network egress.
According to Bob Briscoe, Arnaud Jacquet, Toby Moncaster, and Alan Smith, “Re-ECN: Adding accountability for causing congestion to TCP/IP”, Internet Draft http://tools.ietf.org/id/draft-briscoe-tsvwg-re-ecn-tcp-08.txt, Internet Engineering Task Force, September 2009, it is also recommended by the protocol designers that on events of inactivity for a pre-configured time period (t≧1 sec) the feedback information at the sender should be discarded. It is also depicted as a transition that takes the connection into feedback stale state.
On a given path, the primary functionality of the Congestion Declaration Controller is intelligently setting Congestion Exposure code-points (pre-credits, post-credits) for outgoing traffic while adapting user sending rate (ramping up and down) on a given path with certain path characteristics.
At transport level e.g. TCP, the maximum number of packets unacknowledged in the network is driven by the congestion window size at any time in execution. Initially a sender starts with a minimal congestion window size, e.g. one, and in slow start it ramps up its sending rate (increasing window size) with each arriving acknowledgement (the ramp up of the window depends upon the TCP variant used). On average, after slow start phase, the congestion window is increased by one after a single RTT. For any strategy, to safely pass through functional entities, it is intelligently setting this number of code-points in either of TCP ramping up phases such that deficit at the egress should be less than the sum of pre-credit and post-credit packets.
With the introduction of mobility, e.g. handover as shown in FIG. 2 , instead of focusing on path adaptability, issues related to the path changes have to be addressed especially for a larger congestion window size. FIG. 2 shows as user equipment functioning as mobile node UE/MN which communicates via an access point AP with another user equipment functioning as corresponding node UE/CN. Especially for seamless mobility, a user has no knowledge of expected level of congestion before-hand on the new path. The path adaptability can only happen after a user has received acknowledgements of data packets that it actually transmitted over the new path. These newly arriving acknowledgements carries path view due to changes in offered load introduced by the newly added traffic burst. The challenge is how to set packet code-points, e.g. for indicating congestion, for the very next traffic burst that will occur after a change in attachment point has happened.
Specifically for end points in events of mobility as illustrated in FIG. 2 , the following issues have to be addressed:
The state of new path (congestion, load etc) is not known reliably How to make a reasonable estimate about expected congestion level? Estimation of how much of path has actually been changed (depends on scenario, e.g. in 3GPP) The feedback loop is kind of unreliable due to in-flight packets and acknowledgements The newly arriving feedback might be stale (not reliable) because we are not sure that acknowledgements followed the old or new path For seamless mobility, the selection of code-points for the very next packets that depends on current window size The sender must also take into account the length of handover time, because it should not be more than idle time events
FIG. 3 is a schematic view illustrating an example of an application scenario of a method according to the present invention. A mobile node UE/MN is moved from the old access point O-AP to the next attachment point, i.e. the new access point N-AP. At the new access point N-AP the rest of the path for the mobile node UE/MN remains the same, the prediction factor is only the difference between the marking rate of the old access point O-AP and the new access point N-AP. This information can be exchanged between the two access points, e.g. over the X2 interface in LTE case, and during the handover procedure the new access point N-AP makes this information available to the mobile node UE/MN. Thus, a path congestion prediction factor is calculated that is passed on to the mobile node UE/MN upon the handover event.
FIG. 4 is a schematic view illustrating an example of another application scenario of a method according to the present invention.
Possible paths from within an operator domain are limited. Instead of looking at fine granularity of actual physical paths, congestion information available in data packets is exploited and it is aggregated based on involved network elements on a path within an operator domain for either direction of traffic.
By isolating hint calculation mechanism among individual network elements a Local Congestion View between a set of nodes on the path is constructed. The paths in the operator domain are multiplexed therefore for predicting expected congestion on a new path, the local congestion along these individual set of paths is aggregated to construct hints that are designated as the Global Congestion View.
FIG. 4 shows a possible scenario for having the need of a Global Congestion View. Two handover situations are shown that are inter-eNodeB and inter-SGW (Serving Gateway) handovers. The inter-eNodeB case is a simple one since the difference in congestion can be captured through the local view, e.g. through the difference between marking rate on the eNodeBs.
However for the inter-SGW scenario, the network has to combine congestion information that is occurring between S-GW- 1 and P-GW- 0 (Packet Data Network Gateway) for calculating the prediction factor for congestion on the new (changed) path. The motivation combining such information is due to the reason that congestion from S-GW- 1 to P-GW- 0 is not known reliably at the attachment point.
In the context of Congestion Exposure, congestion signifies the cumulative marking rate across all resources (bottlenecks) along the path. A simplistic approach is representing congestion as fraction (%) along a subset or complete path between communicating end points. Fractions along subset of paths may then be combined to construct a Global View of congestion in predicting traffic for the complete path.
The accuracy of prediction may depend on factors like time scales on which information is exchanged among various network elements in the operator domain. Or the accuracy might be inferred based on statistical changes of the marking fraction etc. However, it is foreseen that the accuracy of the computed network-generated hint is signaled together with the network-generated hint itself and let the recipient of the hint make a decision on how it would react on it and how serious he takes this hint into account.
The communication of the hint can be done in various ways. A possible instance is exchanging congestion information on the air interface on the eNodeB to mobile node interface. Other examples could be through ICMP control messages, piggy-backing it to the signaling messages like the mobility management signaling (mobile IP or 3GPP mobility signaling protocols).
Many modifications and other embodiments of the invention set forth herein will come to mind the one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. | A method for supporting congestion management in a congestion exposure-enabled network, wherein sending hosts and receiving hosts communicate with each other by sending flows of packets over network paths via intermediate routers, which, upon detecting congestion, mark packets of the flows as congestion packets by including congestion information, wherein congestion is indicated to the sending hosts via a congestion feedback mechanism, and wherein the sending hosts, upon receiving congestion indications, declare a subset of the packets they send as congestion response packets by including congestion information, depending on whether the amount of congestion response packets is balanced with the indicated congestion level or not is characterized in that aggregated congestion is determined on the basis of congestion information included in packets that are sent over the network paths between the sending hosts and the receiving hosts. Furthermore, a corresponding congestion exposure-enabled network system and a corresponding intermediate router are disclosed. | 7 |
This is a divisional of application Ser. No. 08/479,124, filed Jun. 7, 1995 now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to an electrical flex circuit, and more particularly to a flex circuit comprising a lattice area with reduced bending and torsional stiffness and reduced thermal expansion properties.
Electrical flex circuits or cables are typically made of copper sheets deposited on a flexible carrier, such as a polymeric sheet. Portions of the copper sheet are masked with a desired pattern. The masked portions are etched to leave the desired pattern in the copper in the form of conductor traces. The pattern corresponds to a particular electrical circuit.
The stiffness of the polymeric sheet and of the copper determine the stiffness of the flex circuit. A desire to reduce or eliminate the torsional and bending stiffness of the flex circuit has led to a search for a super soft carrier or thin material to reduce the stiffness of the entire flex circuit. However, reducing the stiffness leads to a degradation of the flatness of the flex circuit. Also, the polymeric material used to construct the flex circuit is sensitive to temperature fluctuations. Temperature fluctuations can therefore cause undesirable thermal expansion and contraction in the flex circuit.
As a result, typical flex circuits have limited applicability in certain applications, such as in the electrical connections of a head gimbal assembly (HGA) of a disc drive data storage system. The head gimbal assembly is supported by an actuator assembly and includes a disc head slider and a gimbal. The slider carries a transducer for communicating with a recording surface in the storage system. The gimbal provides a resilient connection between the actuator assembly and the slider which allows the slider to pitch and roll while following the topography of the recording surface. The stiffness of traditional flex circuits have limited the applicability of flex circuits between the actuator assembly and the transducer since the stiffness interferes with the pitching and rolling of the slider and thereby adversely affects the flying characteristics of the slider.
SUMMARY OF THE INVENTION
A flex circuit according to the present invention comprises a flexible carrier having a lattice. At least one conductor is carried by the flexible carrier and extends along the lattice. The lattice provides reduced torsional and bending stiffness and reduced thermal expansion properties. The lattice also reduces an effective bond area between the conductor and the carrier yielding less interfacial stresses which improves the flatness of the carrier.
In one embodiment, the lattice is defined by a plurality of spaced apart apertures or depressions. The apertures preferably form a substantially random pattern and have a width that is equal to 0.5 to 1.5 times the width of the conductor. The apertures can have any shape, such as a circular or cross shape.
The flex circuit of the present invention is particularly useful in disc drive data storage systems for carrying conductors between an actuator assembly and a disc head slider. The lattice reduces the bending and torsional stiffness of the flex circuit in the area of the resilient connection between the actuator assembly and the slider such that the flex circuit does not adversely affect the flying characteristics of the slider. The flex circuit of the present invention also isolates the slider from thermal expansion and contraction of the flex circuit due to temperature fluctuations in the disc drive. As a result, the slider has a more consistent flying height with respect to a recording surface.
The flex circuit of the present invention is also useful in supporting electrical conductors between the actuator assembly and electrical circuits secured to the disc drive housing. With the reduced torsional and bending stiffness, the flex circuit of the present invention does not interfere with the actuator in positioning the slider over the recording surface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a flex circuit according to the present invention.
FIG. 2 is a fragmentary cross-sectional view of the flex circuit, taken along lines 2--2 of FIG. 1.
FIG. 3 is a fragmentary cross-sectional view of a flex circuit having apertures that have been pinched through without removal of material.
FIG. 4 is a fragmentary cross-sectional view of a flex circuit having a plurality of depressions.
FIG. 5 is a fragmentary plan view of a flex circuit having cross-shaped apertures.
FIG. 6 is a top plan view of a disc drive data storage system in which the present invention is particularly useful.
FIG. 7 is a perspective view of an actuator assembly shown in FIG. 6.
FIG. 8 is a cross-sectional view of a slider electrically coupled to a flex circuit according to the present invention.
FIG. 9 is a top plan view of a flex circuit attached to an alternative load beam suspension, according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a top plan view of a flex circuit or flex cable 10 having reduced bending and torsional stiffness, according to the present invention. FIG. 2 is a fragmentary cross-sectional view of flex circuit 10, taken along lines 2--2 of FIG. 1. Flex circuit 10 includes a flexible carrier 12 and a plurality of copper conductor traces 14, 16, 18 and 20. Flex circuit 10 can have a single or multi-layered structure. Carrier 12 is formed of an electrically insulating polymeric material, such as polyimide Kapton plastic. "Kapton" is a trademark for a polyimide product manufactured by the E.I. DuPont de Nemours Company of Willmington, Del.
Carrier 12 includes a lattice area 22 having reduced bending and torsional stiffness and reduced thermal expansion relative to an area 24 of continuous carrier material. Lattice area 22 is defined by a plurality of apertures or depressions 30 through carrier 12. The width of each aperture 30 can vary from several microns to tenths of millimeters, depending on the desired flexural strength of the carrier. While apertures 30 can have virtually any size, the apertures preferably have a width that is about 0.5 to 1.5 times the width of conductors 14, 16, 18 and 20.
Apertures 30 can have any shape and are preferably randomly positioned with respect to one another within lattice area 22 so there are no preferred directions of bending. Also, there are preferably as many apertures or depressions per unit area as possible. In the embodiment shown in FIG. 1, apertures 30 have a circular cross section.
Apertures 30 can be laser ablated, punched, etched, pinched or otherwise perforated within carrier 12. Apertures 30 can be distributed throughout lattice area 22 as shown in FIG. 1 or can be restricted to areas other than the areas carrying conductors 14, 16, 18 and 20. Lattice area 22 can be confined to a particular portion of flex circuit 10 at which stresses occur or can extend along the entire flex circuit.
The flex circuit shown in FIGS. 1 and 2 can be constructed by perforating flexible carrier 12 and then depositing or bonding a copper sheet to carrier 12 through an adhesive 32, for example. Portions of the copper sheet are then masked with a desired pattern. The unmasked portions of the copper sheet are etched to leave the desired pattern in the copper sheet in the form of conductor traces 14, 16, 18 and 20, for example.
The conductors can be bonded to either side of carrier 12 or can be laminated within carrier 12. In one embodiment, the conductors are formed on carrier 12 prior to perforating the carrier. In this embodiment, the perforations are positioned around and between the conductors to prevent the perforation operation from damaging the conductors.
FIG. 3 is a fragmentary cross-sectional view of a flex circuit 38 having a flexible carrier 40 in which apertures 42 have been pinched through without removal of material. Conductors 44 are bonded to a surface 46 of carrier 40 with an adhesive 48. In an alternative embodiment, conductors 44 are attached to surface 50 of carrier 40.
FIG. 4 is a fragmentary cross-sectional view of yet another alternative embodiment of the present invention. Flex circuit 58 includes a carrier 60 having a surface 62 with a plurality of depressions 64. Depressions 64 are recessed from surface 62 but do not extend all the way through the carrier. Conductors 66 are attached to surface 64 through an adhesive 68, for example. In an alternative embodiment, conductors 66 are attached to opposing surface 70 of carrier 60.
FIG. 5 illustrates a flexible carrier 80 in which apertures or depressions 82 have a cross shape, as opposed to a circular shape. Once again, the apertures or depressions 82 are preferably randomly positioned with respect to one another such that there is no preferred direction of bending. The cross shape allows the apertures or depressions 82 to be placed closer together than the circular shape shown in FIG. 1. As can be seen in FIG. 5, the cross-shaped apertures 82 overlap one another in a longintundal direction Y and in a width direction X.
The perforated flex circuit of the present invention has reduced torsional and bending stiffness and reduced thermal expansion. Also the apertures reduce the effective bond area between the conductors and the flexible carrier which yields less interfacial stresses and results in improved flatness in the flex circuit.
The stiffness of the flexible carrier and the conductors determine the stiffness of the flex circuit. The apertures in the lattice area cause the flexural strength of the lattice area to be dominated by the flexural strength of the conductors which can be deposited or laminated in a very thin layer. Since the displacement and rotation of a simple plate is proportional to the modulus of elasticity of the material and proportional to the thickness cubed and linearly proportional to the width and length of the plate, a very thin layer of copper is yields extremely low bending and torsional stiffness.
A series of finite element models was prepared according to the present invention. A square "cell" with a polyimide layer and a copper layer was used to represent a portion of the flex circuit. A smaller square portion was removed from the center of the polyimide layer of the cell to represent an aperture in the polyimide layer. The cell was copied and adjoined to create a flex circuit model one cell wide and two cells long.
The input and result of the finite element models were given in ratios of unit width and thickness. The width of the copper layer (conductor traces) was held constant at W. The size of the cell was held constant at 3W on each side. The pitch spacing of the copper traces and aperture were also 3W. The size of the aperture in the polyimide layer was varied from 0.5W from to 1.5W square. The thickness of the copper layer was held constant at a thickness of t, with t equal to W/10. The thickness of the adhesive was varied from 0.5t to 2.0t.
Three parameters were calculated, including cantilevered beam bending stiffness, torsional stiffness, and out of plane deflection due to thermal expansion. The bending and torsional stiffness results showed that it is much more effective to have a thin polyimide layer with no apertures than a thick polyimide layer with large apertures. The presence of large apertures has a significant and beneficial effect if the polyimide layer is thicker than the copper layer. Small holes have a very small effect in all thicknesses of polyimide.
The out-of-plane deflection due to thermal expansion results show that it is best to have a polyimide layer thinner than the copper layer. The presence of large holes therefore has a significant and beneficial effect regardless of the relative thickness of the polyimide layer. Small holes have a very small effect in all thicknesses of polyimide.
Another advantage of the present invention is that the apertures or depressions isolate thermal expansion in the flex circuit. Polymeric materials absorb humidity and thus exhibit out-of-plane deflection due to thermal expansion. With continuous material, the bulk of material follows the deflection load. However, with the addition of perforations, material stress caused by thermal expansion is localized and distributed around the perforations, thereby isolating deflection and expansion forces. The perforated flex circuit of the present invention is therefore less sensitive to temperature fluctuations than non-perforated flex circuits.
The perforated flex circuit also has a lower dielectric constant. In many applications, the conductors on the flex circuit carry high frequency signals in which the electrical charge travels around the side or surface of the conductor. Since the effective bond area between the conductor and the carrier is less, there is less interference between the charge and the carrier, resulting in a lower dielectric constant.
FIG. 6 is a top plan view of a disc drive data storage system in which the present invention is particularly useful. Disc drive data storage system 100 includes a housing base 102 and a top cover 104. A disc 106 is mounted for rotation on a spindle motor (not shown) by a disc clamp 108. Disc 106 can include a plurality of individual discs which are mounted for co-rotation about a central axis. Each disc surface has an associated head gimbal assembly (HGA) 110 for communicating with an associated disc surface. HGA 110 is supported by a load beam flexure or suspension 112 which is in turn attached to a head mounting arm 114 of an actuator body 116.
The actuator shown in FIG. 6 is of the type known as a rotary moving coil actuator and includes a voice coil motor (VCM), shown generally at 118. Voice coil motor 118 rotates actuator body 116 about a pivot 120 to position HGA 110 over a desired data track along an arcuate path 122. Electronic circuitry 124 energizes voice coil motor 118 and communicates with HGA 110 to read and write information at desired locations on the disc surface. While a rotary actuator is shown in FIG. 6, the present invention is also useful in disc drives having other types of actuators, such as linear actuators.
Electrical connections between electronic circuitry 124, voice coil motor 118 and HGA 110 are carried by one or more flex circuits 126 in accordance with the present invention. Flex circuit 126 extends between connector 130 and head mounting arm 114. A flex circuit 128 routes selected conductors from flex circuit 126 to HGA 110. Flex circuit 128 can be connected directly to flex circuit 126 or can be connected through intermediate circuitry such as a preamplifier.
FIG. 7 is a perspective view of the actuator assembly shown in FIG. 6. Flex circuit 126 extends between connector 130 and preamplifiers 140 and 142 which are attached to head mounting arm 114. Connector 130 is coupled to electronic circuitry 124 which is attached to the housing. Flex circuit 126 includes a lattice area 132 in accordance with the present invention. Lattice area 132 can be confined to a particular area along flex circuit 126 or can extend over the entire flex circuit. Lattice area 132 allows the actuator assembly to pivot freely about pivot 120 without interfering with the positioning of HGA 110. An additional flex circuit 134 extends between voice coil motor 118 and electronic circuitry 124 and can include one or more lattice areas 136 according to the present invention.
HGA 110 includes air bearing disc head slider 150 which is resiliently attached to a load beam flexure 112. Slider 150 supports a transducer for communicating with the disc surface. The transducer is electrically coupled to preamplifiers 140 and 142 through flex circuit 128. Flex circuit 128 includes a lattice area according to the present invention such that the flex circuit does not interfere with the flying characteristics of slider 150.
FIG. 8 is a cross-sectional view of slider 150 which is electrically coupled to flex circuit 128. Flex circuit 128 includes a polyimide carrier 160 and a plurality of copper conductors 162. Polyimide carrier 160 has a plurality of apertures or depressions 164 according to the present invention. The copper conductors 162 are attached to corresponding bond areas 166 of slider 150. Slider 150 supports a transducer (not shown) along an air bearing surface 168, which communicates the disc surface.
As the disc rotates, the disc drags air beneath rails 170, 172 and 174 which developed positive pressure that causes the slider to lift and fly above the disc surface. Apertures or depressions 164 in polyimide carrier 160 prevent flex circuit 128 from interfering with the pitching and rolling of slider 150 as it follows the topography of the disc surface.
The desire to use flex circuits between the transducer and the actuator is based on the miniaturization of disc drive storage systems and a desire for greater automation. However, head gimbal assemblies are now being developed with sliders that are 50% and even 30% the size of traditional sliders. A 30% size slider has a length of only 49 mills and a width of only 39 mills. Sliders of this size require gimbals having very low pitch and roll stiffness. Existing flex circuits are therefore difficult if not impossible to use in such applications due to the thickness and stiffness of the flex circuit.
An additional limitation of existing flex circuits is the sensitivity of the polymeric material to temperature fluctuations. The sensitivity results in a change in the pitch static angle (PSA) and the roll status angle (RSA) of the slider with temperature. Changes in the PSA and RSA result in undesirable changes in fly height with temperature, especially for low flying sliders.
In contrast, the perforated flex circuit of the present invention has reduced torsional and bending stiffness and reduced thermal expansion characteristics. The perforated flex circuit yields extremely low static pitch and roll moments and is therefore particularly useful for making electrical connections to a transducer in a head gimbal assembly.
FIG. 9 is a top plan view of an alternative load beam flexure or suspension 180. Suspension 180 is attached to a base plate 182 and carries a flex circuit 184 according to the present invention. Flex circuit 184 extends from base plate 182 to a head gimbal assembly (HGA) 186. Flex circuit 184 supports a plurality of conductors 188 for communicating to and from HGA 186. Conductors 188 are coupled to a slider (not shown) at a bonding area 190. In one embodiment, flex circuit 184 includes a lattice area of apertures or depressions which is located along HGA 186. In another embodiment, the lattice area extends along the entire suspension 180.
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. For example, the perforated flex circuit of the present invention can be used in many applications. The apertures or depressions can have many shapes and sizes. Also, the particular connections between the flex circuit and various components of the disc drive are provided only as examples. Numerous other connections and configurations can be used in accordance with the present invention. | A flex circuit comprises a flexible carrier and at least one conductor carried by the flexible carrier. The flexible carrier includes a lattice which provides reduced torsional and bending stiffness and reduced thermal expansion properties. | 6 |
[0001] The present application claims the benefit of U.S. provisional application No. 60/193,976, filed on Mar. 31, 2000, incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to innovative blends of select compost and one or more natural, organic fibrous materials that act as mechanical tackifiers. Compost blends of the present invention exhibit improved performance in landscape management, and are particularly useful in the form of mats and berms for the prevention and treatment of erosion and the control of sedimentation. They also serve to remediate water runoff of excess nutrients, pesticides, metals, and numerous other environmental pollutants.
[0004] 2. Background
[0005] Concern for our natural resources and landscapes is widespread. Preservation of the environment is essential.
[0006] Significant interest with respect to preservation of the environment has focused on general landscape management including soil erosion control, water runoff and soil movement.
[0007] Control of soil erosion is necessary regardless of the size of or the distance of a site from surface waters. Erosion control is essential to protect not only water quality but also valuable, irreplaceable soils as well.
[0008] Preventing and treating soil erosion continues to be of significant concern, worldwide. For example, within the United States alone, the Department of Agriculture reports that more than 2 billion tons of topsoil are lost through erosion every year. The soil left behind eventually becomes too poor to sustain good plant growth.
[0009] Soil which is eroded away usually is carried into wetlands, ponds, streams, lakes and rivers. The sediment itself and the associated fertilizers, pesticides and other toxic materials affect the ecological balance and health of aquatic organisms and the food chains that depend on them. This pollution also compromises the commercial, recreational and aesthetic value of waterways. As a result, preventing and treating erosion is critical for protecting the quality of water resources and for maintaining the quality and productivity of soil.
[0010] Further, although erosion is a naturally occurring process, it is greatly aggravated by construction and agricultural practices that disturb vegetation and the soil surface. The U.S. Environmental Protection Agency (EPA) continues to list storm water runoff from cities and construction sites as being one of the leading causes of poor water quality.
[0011] To reduce soil erosion and sedimentation from new construction sites and other land clearing activities, the EPA has mandated that slope stabilization and erosion and sediment control measures be employed for construction projects disturbing more than 5 acres. State and local laws commonly require the use of erosion and sediment control technologies on all construction sites.
[0012] Numerous products have been developed in an effort to control erosion and sediment. Such products include geosynthetic membranes, mats, fabrics, blankets, grids and cellular confinement systems, as well as silt fencing, hay bales, logs (or wattles) and berms. Some of these products are permanent and require removal upon completion of the project. Other systems are biodegradable to various degrees.
[0013] In addition, fiber mulch (i.e., hydromulch) and chopped hay/straw have been used in conjunction with chemical tackifiers (i.e., binders) to cover, control erosion and to apply seed to bare soil.
[0014] Despite advancements in the field, it remains highly desirable to develop improved materials and methods for landscape management, particularly in the areas of erosion control and sedimentation. It would be highly desirable for such materials to be biodegradable (no removal required) and environmentally safe. It also would be highly desirable for such materials to be easy to apply, cost effective, aesthetically pleasing, promoting of soil structure and quality, and nourishing to vegetation.
SUMMARY OF THE INVENTION
[0015] We have discovered innovative blends of compost and various natural, organic fibrous materials that serve to mechanically/physically bind the composite together while providing porosity and water conductivity to the resulting product. Compost blends of the present invention are particularly suitable in landscape management for use as mats that prevent erosion, filter berms that control erosion and remove sediment from water runoff, substrate for revegetation of slopes, the basis of organic soil generation on inclined rocky or gravelly terrain, and a system for the bioremediation of water runoff containing excess nutrients, pesticides, metals, or numerous other environmental pollutants.
[0016] Mats and filter berms constructed in accordance with the materials and methods of the present invention hold soil and seed in place, create a microclimate that favors seed germination, reinforce the root zone to maintain vegetal cover, reduce water runoff velocities, and prevent and/or control sedimentation.
[0017] In preferred embodiments, compost of the present invention comprises a solid mature product resulting from composting, which is a managed process of biooxidation of a variety of solid organic substrates that includes a thermophilic phase. Particularly preferred materials for the production of compost include, for example, food residuals, food processing wastes, paper products, yard trimmings, animal manures and beddings, agricultural vegetable wastes, and the like.
[0018] Preferred fibrous materials for use in connection with the invention include the following: shredded tree roots or vines as well as naturally occurring organic fibrous materials such as abaca, coir, cotton, flax, jute, hemp, sisal, vines, wool, and the like.
[0019] We have surprisingly discovered that use of a fibrous mechanical tackifier in blends of the invention provides significant advantages relative to solid earth berms and other traditional barriers. For example, the mechanical tackifier promotes water filtration through the compost. Use of a mechanical tackifier in the compost blend provides an optimal consistency which is loose enough to prevent the compost from packing down, but firm enough to prevent undesirable breakthrough. Use of a tackifier in blends of the invention permits enhanced contact between the compost and water. The result is greater improve consumption of nutrients and remediation of pollutants from water, and more effective cleansing of sediment.
[0020] The specifications for compost to be used by itself as an erosion control material are provided by the leading national authority on the characterization and use of compost, the U.S. Composting Council. (See, e.g., U.S. Composting Council (1996) Field Guide to Compost Use ; U.S. Composting Council (1996) Suggested Compost Parameters & Compost Use Guidelines .)
[0021] Compost blends of the present invention are environmentally friendly. They utilize organic materials, including recycled organic materials, which significantly enhance soil quality and the nutrient supply to plants. Berms of the present invention are also navigable to turtles, salamanders, and other animals (conventional silt fences/straw bales prevent this). Additionally, berms of the present invention naturally remove pollutants such as excess plant nutrients, pesticides, heavy metals, and petroleum-based substances in water leaching off of roadways, agricultural and industrial land, turf intensive areas (e.g., athletic fields, golf courses, etc.), and residential properties.
[0022] Other benefits, especially of compost-blended mats, include decreased water runoff (corresponds to increased infiltration and available water for seed and plant establishment) and decreased settleable/suspended solids (corresponds to increased soil remaining on slopes and not in waterways).
[0023] Compost-blended filter berms of the present invention are cost efficient. For example, minimal materials are needed, and labor/time consumption is significantly reduced as compared to traditional berm construction and installation.
[0024] Compost-blended mats and filter berms of the invention are easily installed. No clean up or removal is necessary. Compost filter berms of the invention are preferably applied with a compressed-air blower system as will be appreciated by those skilled in the art. Such a system typically comprises an applicator hose connected to a holding area/reservoir (e.g., on a truck). In that way, projects can be completed much faster. No heavy equipment needs to travel on the terrain where the mats or berms are to be installed, thus decreasing compaction of existing soils or the destruction of existing vegetation. The applicator hose can reach hard to access areas and can extend to 500 ft or more.
[0025] Further, vegetation grows from the berm, maintaining a natural appearance. It fits into the natural landscape in many situations. This presents a tremendous savings in terms of labor compared to traditional materials such as straw bale/filter fabrics which need to be collected after the project is completed. Additionally, straw bale/filter fabrics are wasted, e.g., disposed of rather than reused, adding unnecessary materials to landfills.
[0026] Compost-blended filter berms of the present invention may be applied in areas where water has already accumulated. Berms of the invention may be constructed on substantially level areas or on slopes of varying degrees. Also, if a more level area is desired on any given slope, the berm may be applied in a more spread out fashion. In that way, the berm also lessens the degree of the slope, further slowing the velocity of water runoff.
[0027] Compost-blended filter berms of the present invention are aesthetically pleasing. For instance, vegetation adds greenery to the landscape, contrary to the barrenness caused by erosion and the unattractiveness of hay bales/silt fence. Additionally, berms of the invention are not limited to traditional designs, as the compost blends may be blown in to a target site in any of a number of configurations.
[0028] Other aspects of the invention are discussed infra.
BRIEF DESCRIPTION OF DRAWINGS
[0029] [0029]FIG. 1 shows a compost-blended filter berm constructed on a slope in a preferred embodiment of the invention.
[0030] [0030]FIG. 2 shows multiple compost-blended filter berms in an alternate preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] As noted above, erosion control and sedimentation have become major environmental concerns. It is critical that we reduce pollution and manage our landscapes more effectively. The primary forces of erosion include wind and water. These forces create conditions that are destructive to the environment.
[0032] We have discovered innovative compost blends with mechanical tackifiers which are all natural organic materials. Blends of the present invention are suitable for use in landscape management, particularly in erosion and sediment control and the bioremediation of pollutants in water runoff.
[0033] Additionally, the organic materials utilized for blends of the invention may comprise a variety of recycled materials, thereby presenting a further environmental advantage.
[0034] In preferred embodiments, compost of the present invention comprises a solid mature product resulting from composting, which is a managed process of biooxidation of a variety of solid organic substrates that includes a thermophilic phase. Particularly preferred materials for the production of compost include, for example, food residuals, food processing wastes, paper products, yard trimmings, animal manures and beddings, agricultural vegetable wastes, and the like.
[0035] Suitable compost products are chosen in view of the U.S. Composting Council's guidelines for compost used by itself to control soil erosion (U.S. Composting Council (1996) Field Guide to Compost Use ; U.S. Composting Council (1996) Suggested Compost Parameters & Compost Use Guidelines ).
[0036] To perform the selection, compost from a variety of sources and producers is tested to ensure its suitability. A variety of commercial certified laboratories are available for such testing as will be appreciated by those skilled in the art. These laboratories adhere to the analytical procedures recommended by the U.S. Composting Council and published in “ Test Methods for the Examination of Composting and Compost ” (1997).
[0037] We specify the following compost parameters in accordance with the guidelines developed by the U.S. Composting Council: levels of regulated chemicals; pathogens; viable weed seeds; man-made inerts; particle size and texture; biological stability; maturity; phytotoxicity (growth screening); germination and growth; bulk density; moisture content; organic matter content; ash content; pH; soluble salt content (electrical conductivity); and total salt content. Also, in accordance with the specifications established by the U.S. Composting Council, plant nutrient content is considered in terms of nitrogen (organic, ammonium and nitrate nitrogen); phosphorus; potassium; secondary nutrients (calcium, magnesium, sulfur, and sodium); micronutrients (zinc, iron, manganese, copper, and boron); organic matter carbon; carbon-to-nitrogen ratio; free air space; drainage, infiltration and permeability; hydraulic conductivity; and water holding capacity.
[0038] Preferred fibrous materials for use in connection with the invention include the following: shredded tree roots or vines as well as naturally occurring organic fibrous materials such as abaca, coir, cotton, flax, jute, hemp, sisal, vines, wool, and the like.
[0039] We have surprisingly discovered that use of a fibrous mechanical tackifier in blends of the invention provides significant advantages relative to solid earth berms and other traditional barriers. For example, the mechanical tackifier promotes water filtration through the compost. Use of a mechanical tackifier in the compost blend provides an optimal consistency which is loose enough to prevent the compost from packing down, but firm enough to prevent undesirable breakthrough. Use of a tackifier in blends of the invention permits enhanced contact between the compost and water. The result is greater consumption of nutrients and remediation of pollutants from water, and more effective cleansing of sediment.
[0040] It will be appreciated that the proportion of organic compost to mechanical tackifier (the natural, organic fibrous material) will vary widely depending on the specific needs of the situation, but may readily be determined empirically by one skilled in the art based on the present disclosure. It is generally preferred that the compost to mechanical tackifier be in the range of about 25:75 (v:v) to about 50:50 (v:v).
[0041] Other variables which can be readily determined by those skilled in the art based on the present disclosure include the degree of porosity, amount of physical interlacing of the compost required, the fineness of the kind of fiber used, and the like.
[0042] Compost-blended mats and filter berms constructed in accordance with the present invention are a particularly effective method of preventing and controlling precious soils from wearing away. Further, compost-blended filter berms of the invention prevent unwanted chemicals from leaching into our wetlands and waterways.
[0043] Compost-blended mats and filter berms of the invention may be constructed in areas where erosion already has become a problem or in areas which are vulnerable to erosion in the future. Construction on slopes of varying degrees is feasible using blends and methods of the present invention. In some instances, construction of multiple berms will be desirable, e.g., a first berm built at the bottom of a slope and a second berm built at the top of the slope.
[0044] Compost blends of the invention can be blown in to the target site in a variety of configurations. For example, it may be blown in to create a mound (i.e., berm), between about 1 and 10 feet in width, more preferably between about 3 and 4 feet in width; and between about 1 and 5 feet in height, preferably about 1 to 2 feet in height. Lengths of the berms are indefinite depending on the situation. Compost blends of the invention can also be blown in as mats that will take on the configuration of the slope. Blends of the invention may be blown onto preexisting ground or into areas where water has accumulated.
[0045] The installation of compost-blended filter berms of the invention control and eradicate the effects of erosion by acting as a sieve. As the water runoff and sediment flow through the compost mixture, the microorganisms in the compost degrade pollutants and contaminants such as hydrocarbons and other algae promoting substances. Compost blends of the invention retain sediments and moisture, continuously replenishing the organic matter necessary in completing decomposition. This process results in less settleable and soluble solids, and prevents chemicals and undesirable sediment from reaching our water supplies.
[0046] Compost-blended filter berms of the present invention are environmentally friendly in comparison to other methods of erosion control such as silt and sediment fences and staked straw/hay bales. Berms of the present invention are completely natural, organic, and aesthetically pleasing as well. Berms of the present invention do not require removal once the project has been completed. Indeed, the berms may stay in place as long as desired.
[0047] Compost blends of the invention can be used in constructing compost filter berms with ease and efficiency using a blower system/applicator hose as will be appreciated by those skilled in the art.
[0048] Also, though blends of the invention are rich in slow release forms of nitrogen, phosphorus, potassium and other nutrients, they do not release these nutrients into the surrounding environment. When used to control storm water runoff and erosion, they assimilate these materials and prevent water pollution. The compost blends of the invention not only are effective soil nutrient management tools, they are pleasing to the eye as well.
[0049] Referring to FIG. 1, a compost filter berm constructed in accordance with the present invention is shown on a slope. As shown, the compost filter berm acts as a natural water and sediment filter. As soil and water runoff enter the berm, microorganisms living in the compost degrade and decompose hazardous and harmful materials, while absorbing water.
[0050] Referring now to FIG. 2, the use of multiple compost berms (mounds) are shown. For example, on particularly steep slopes, compost berms of the invention can be used at the top and/or bottom of the slope to slow the velocity of water and provide additional protection for receiving waters.
[0051] The use compost filter berms of the invention for erosion control allows less sediment and chemicals to leach into waterways. Further, the use of compost blends of the invention for amending native soils improves organic matter content and reduces the ability of that soil to erode. Blends of the invention also improve seed establishment and plant growth, further reducing soil erosion.
[0052] Compost filter berms of the invention can be used in place of traditional silt fences and straw bales at a lower cost while providing safer and more environmentally stable conditions for animals in and around our landscapes.
[0053] The foregoing description of the invention is merely illustrative thereof, and it is understood that variations and modifications can be made without departing from the spirit or scope of the invention as set forth in the following claims. Further, all references cited herein are incorporated by reference. | The present invention provides innovative blends of select compost and one or more natural, organic fibrous materials that act as mechanical tackifiers. Compost blends of the present invention exhibit improved performance in landscape management, and are particularly useful in the form of mats and berms for the prevention and treatment of erosion and the control of sedimentation. They also serve to remediate water runoff of excess nutrients, pesticides, metals, and numerous other environmental pollutants. | 4 |
BACKGROUND OF THE INVENTION
The invention relates to methods and apparatus for manipulating webs of paper or the like, and more particularly to improvements in methods and apparatus for folding continuous webs of paper or the like (hereinafter called webs or paper webs). Still more particularly, the invention relates to improvements in methods and apparatus for zig-zag folding continuous paper webs of the type wherein successive sections or panels of the webs are connected to each other by weakened web portions, particularly by transversely extending lines of perforations, slits or the like.
The provision of equidistant or otherwise distributed transversely extending weakened portions (hereinafter called perforations or rows of perforations) in paper webs which are to be folded in zig-zag fashion is desirable in order to allow for predictable folding of the webs and for the formation of stacks which are easy to handle. In accordance with a known proposal, a paper web is fed vertically downwardly and is taken over by two endless belt conveyors which diverge to define a downwardly expanding triangular chamber and have grippers serving to engage the web in the regions of alternate rows of perforations to thus convert the web into a stack wherein the panels are piled up on top of each other in zig-zag fashion. Reference may be had to German Offenlegungsschrift No. 22 64 633.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved method of zig-zag folding webs of paper or the like in a small area, with a high degree of predictability, and without undesirable creasing of the web.
Another object of the invention is to provide a method which can be practiced for the folding of wide, narrow, lightweight, relatively heavy, sensitive or sturdy webs with the same degree of facility and predictability.
A further object of the invention is to provide a method which renders it possible to ensure that successive panels of the web accurately overlap each other.
An additional object of the invention is to provide a method which can be utilized to form a succession of stacks of zig-zag folded panels each of which contains a predetermined number of stacked panels.
A further object of the invention is to provide a novel and improved apparatus for the practice of the above outlined method and to construct and assemble the apparatus in such a way that its space requirements (particularly its height) are a mere fraction of the space requirements of conventional zig-zag folding apparatus.
Still another object of the invention is to provide the apparatus with novel and improved means for converting a continuous web with transversely extending weakened zones into a series of discrete stacks of folded panels wherein each stack contains a predetermined number of panels.
A further object of the invention is to provide an apparatus which can reliably fold a wide variety of webs having different dimensions and/or other characteristics.
An additional object of the invention is to provide the apparatus with novel and improved means for diverting selected panels of the web from their path on the way toward a stacking station.
Another object of the invention is to provide the apparatus with novel and improved means for rapidly folding each oddly numbered panel of the web over or under the immediately preceding or following evenly numbered panel.
One feature of the present invention resides in the provision of a method of zig-zag folding a continuous web of paper or other flexible material which has alternating first and second panels connected to each other by transversely extending weakened zones in the form of rows of perforations or the like. The method comprises the steps of transporting the web at a first speed in a predetermined direction and along a first path, diverting at least a portion of each of successive first panels from the first path into a second path (such second path is or can be at least substantially parallel to the first path and each path can be horizontal or nearly horizontal), and advancing the diverted first panels along the second path at a lower second speed while continuing to transport the second panels which immediately follow the diverted first panels at the first speed to ensure that at least one of each pair of panels including a diverted first panel and the immediately following second panel develops a loop and the second panel of the pair of panels overlies the respective first panel.
The diverting step can include establishing a pressure differential between opposite sides of each first panel so that the first panels are moved sideways and enter the second path, and the advancing step then includes attracting the diverted first panels to at least one driven conveyor, at least during the initial stage of the formation of a loop in the at least one panel of the respective pair of first and second panels.
The advancing step can include gradually decelerating the first panels from the first to the second speed or stepwise decelerating the first panels from the first to the second speed. The second speed can embrace a range of speeds, preferably a series of speeds wherein each preceding speed exceeds the next-following speed.
The transporting step can include pushing the second panels in the predetermined direction in the course of the diverting step, and such pushing step can include attracting the second panels by suction to at least one driven conveyor, e.g., to a foraminous overhead belt conveyor.
The method preferably further comprises the step of stabilizing the loops, including admitting one or more jets of air or another suitable gaseous fluid into the loops.
The advancing step preferably includes moving the diverted first panels at a speed less than the speed of the immediately following second panels until the second panels at least nearly completely overlie the immediately preceding first panels. Such method preferably further comprises the step of accumulating the overlapped first and the overlapping second panels into a stack. An additional step of the method can include severing the weakened zones between selected first and immediately following second panels in the stack.
Another feature of the invention resides in the provision of an apparatus for zig-zag folding a continuous web of paper or a like flexible material which has alternating first and second panels connected to each other by transversely extending weakened zones in the form of rows of perforations or the like. The apparatus comprises a transporting unit which serves to move the web lengthwise along a first path in a predetermined direction and at a first speed, and means for diverting portions at least of successive first panels from the first path into a second path and for advancing the diverted first panels along the second path at a lower second speed so that at least one of each pair of panels including the diverted first panel and the immediately following second panel develops a loop as the second panel of such pair of panels continues to move at the first speed. The second path can be offset with reference to the first path substantially at right angles to the predetermined direction, and the diverting means can include means for defining a step between the first and second paths, i.e., between the transporting means and the advancing means of the diverting means.
The diverting means can comprise a foraminous conveyor and a suction chamber adjacent one side of the foraminous conveyor to attract successive first panels to the other side of the foraminous conveyor.
In addition to or in lieu of the just mentioned foraminous conveyor, the diverting means can comprise at least one panel-decelerating conveyor means arranged to (directly or indirectly) receive first panels from the transporting means and to advance the first panels at the second speed. For example, the diverting means can comprise a battery or series of two or more panel-decelerating conveyor means wherein each preceding conveyor means is faster than the immediately following conveyor means. Such apparatus can further comprise overhead conveyor means overlying the diverting means and having means for attracting the loops and for pushing the thus attracted loops in the predetermined direction. The panel-decelerating and/or the overhead conveyor means can be foraminous, and the apparatus then further comprises suction chambers cooperating with the foraminous conveyor means to attract first panels to the decelerating conveyor means and to attract the loops to the overhead conveyor means.
The apparatus preferably further comprises means for stacking the first and second panels on top of each other downstream of the diverting means, and means for severing selected weakened zones of the web in the stacking means so that each of the thus obtained discrete stacks contains a desired number of overlapping first and second panels.
The apparatus preferably further comprises means for stabilizing the loops, and such stabilizing means can comprise one or more nozzles or other suitable means for admitting air or another gaseous fluid into the loops.
The second path is or can be substantially or exactly parallel to the first path, and the diverting means preferably (but not necessarily) includes means for looping the second panels of successive pairs of immediately adjacent first and second panels.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
The FIGURE is a schematic partly elevational and partly vertical sectional view of a folding apparatus which embodies one form of the invention and whose diverting unit comprises a series of five interlinked decelerating conveyors.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The combined folding and stacking apparatus which is shown in the drawing comprises a web transporting unit 1, a diverting unit 2 and a stacking unit 3. The transporting unit 1 serves to advance a continuous web 9 of coherent panels or sheets 41 lengthwise in the direction of arrow 4a and at a first speed preferably matching the speed of the web as it issues from a perforating station where the zones or regions 39 between neighboring panels 41 are weakened by rows of transversely extending perforations, slits or the like. The means for defining a substantially horizontal (first) path for the web 9 comprises an endless belt conveyor 7 which is trained over several pulleys 8 (only one shown in the drawing) and is driven at the first speed by an electric motor M1 or another suitable prime mover which transmits torque to the shaft 8a for the illustrated pulley 8. The transporting unit 1 preferably further comprises an endless foraminous overhead belt conveyor 4 which is trained over several pulleys 6 (only one shown). The shaft 6a for the illustrated pulley 6 is driven by the motor M1 at the speed of the belt conveyor 7. The web 9 is caused to advance in the channel between the substantially horizontal upper reach of the conveyor 7 and the adjacent lower reach of the conveyor 4.
The panels 41 of the web 9 are preferably congruent so that each next-following (second) panel (41b) of a pair of neighboring panels 41 can accurately overlie the immediately preceding (first) panel 41a of such pair of panels. Thus, it can be said that the web 9 consists of a series of successive pairs of first and second panels 41a, 41b and that weakened zones 39 are provided between the panels (41a, 41b) of each pair of panels as well as between the second panel 41b of a preceding pair and the first panel 41a of the next-following pair. It is clear that the web 9 can consist of or that it can contain a flexible material other than paper, e.g., metallic or plastic foil or lightweight cardboard.
Each of the belt conveyors 4, 7 (as well as each other belt conveyor used in the apparatus of the present invention) can comprise, and often comprises, two or more endless belts which are disposed in parallel vertical planes and are trained over sets of coaxial pulleys in a manner well known from the art of transporting webs, panels and sheets of paper or the like. For example, the conveyor 4 can comprise two, three or more discrete endless belts which are trained over discrete pulleys 8 on the shaft 8a or over a single pulley which is driven by the shaft 8a, as well as over discrete idler pulleys (not shown) or a common idler pulley on at least one additional shaft of the transporting unit 1.
The diverting unit 2 comprises a transversely extending ledge 13 whose upper side is flush with the upper side of the upper reach of the conveyor 7 and which defines a step at a location 12 where successive first panels 41a are diverted from the path which is defined by the conveyors 4 and 7. The diversion takes place in a direction at right angles to that which is indicated by the arrow 4a and such diversion is effected by a suction chamber 14 in conjunction with the upper end 11a of an endless foraminous first belt conveyor 11 of the diverting unit 2. The conveyor 11 constitutes the first component of the means for advancing successive first panels 41a along a second horizontal path which is parallel to the path between the conveyors 4, 7 of the transporting unit 1 and wherein the panels 41a advance at a second speed less than the speed of the conveyors 4 and 7. The ledge 13 overlies a portion of the upper reach 11a and its height determines the extent to which the panels 41a are diverted or deflected from the path between the conveyors 4 and 7 of the transporting unit 1. The upper side of the suction chamber 14 has an opening (actually a composite opening composed of apertures in the form of slots, holes and/or analogous passages for air) which is adjacent to the underside of the upper reach 11a of the conveyor 11 and can be sealed or exposed by a plate-like valving element 17 at the upper end of a motion transmitting rod 19 which is reciprocable in a bore of a stationary guide member 18 and carries a roller follower 21 tracking a rotary cam 22 deriving motion from the motor M1, e.g., through the medium of the shaft 8a for the front pulley 6 of the belt conveyor 7. The purpose of the suction chamber 14 is to intermittently establish a pressure differential between opposite sides of the web 9 (namely between opposite sides of successive panels 41a) by way of the upper reach 11a of the foraminous conveyor 11 and to thus divert successive panels 41a from the path which is defined by the conveyors 4, 7 of the transporting unit 1. The torque transmitting connection between the shaft 8a and the cam 22 is such that the movements of the valving element 17 to and from its sealing position are synchronized with the advancement of successive panels 41a along the path which is defined by the conveyors 4 and 7.
The reciprocable valving element 17 can be replaced with a pivotable valving element without departing from the spirit of the invention. When the valving element 17 descends to permit atmospheric air to flow into the suction chamber 14 through the perforations or pores of the upper reach 11a, the upper side of the upper reach 11a attracts the oncoming panel 41a and causes the immediately following panel 41b to develop a loop 42 which grows as the just discussed panels 41a, 41b advance along the suction chamber 14 because the speed of the upper reach 11a is less than the speed of the conveyors 4 and 7. The means for driving the conveyor 11 at a speed which is less than the speed of the conveyors 4 and 7 includes a second electric motor M2 or an analogous prime mover which transmits torque to the shaft for the lower pulley 23 of the conveyor 11. The two upper pulleys 23a, 23b are disposed at the left-hand and right-hand ends of the upper reach 11a and define for successive panels 41a a horizontal path which is parallel to and disposed at a level below the path between the conveyors 4 and 7. The pulleys 23a and 23b need not be driven.
The diverting unit 2 further comprises a series 24 of interlinked panel-decelerating conveyors 24a and 24e which are driven at a progressively lower speed, i.e., the speed of the conveyor 24a exceeds the speed of the conveyor 24b, and so forth. This ensures a gradual deceleration of successive panels 41a during travel toward the stacking station 3. Each conveyor of the series 24 of conveyors comprises one, two or more endless foraminous belt conveyors whose upper reaches are in line with the upper reach 11a and are disposed above discrete suction chambers 28 so that the upper reaches of the conveyors 24a to 24e can attract the panels 41a during advancement of such panels toward the stacking station 3. The prime movers for the conveyors 24a to 24are respectively shown at M3, M4, M5, M6 and M7. These prime movers can constitute variable-speed electric motors, the same as the prime movers M1 and M2, and they can drive the respective panel-decelerating conveyors at desired speeds to effect an appropriate deceleration of the panels 41a during travel of such panels from the upper reach 11a toward an accumulating magazine 36 at the station for the unit 3. Such series of conveyors are well known in the paper processing industry, therefore the motion transmitting connections between the motors M3-M7 on the one hand and the belts of the conveyors 24a to 24e on the other hand are not shown in full detail. In the drawing, the visible pulleys 26 are fixedly mounted on the shafts which are driven by the motors M4 and M6, respectively. The visible pulleys 27 are idler pulleys which are rotatably mounted on their respective shafts. The motor M3 drives the shaft for the idler pulley or pulleys 23b; such shaft carries the driven pulley or pulleys for the conveyor 24a. These driven pulleys, not shown, are mounted behind the pulley 23b. The idler pulley or pulleys (not shown) for the conveyor 24a are mounted on the shaft for the driven pulleys 26 of the conveyor 24b. The driven pulley or pulleys of the conveyor 24b are driven by the motor M4, and the conveyor 24b is further trained over one or more idler pulleys 27 one of which is visible on the shaft for the driven pulley or pulleys, not shown, of the conveyor or conveyors 24c. These driven pulleys of the conveyor 24c are driven by the motor M5, and the conveyor or conveyors 24c are further trained over one or more idler pulleys (not shown) on the shaft (driven by the motor M6) for the driven pulley or pulleys 26 (one of which can be seen) of the conveyor or conveyors 24d. The idler pulley or pulleys 27 for the conveyor or conveyors 24d (one of these pulleys is shown) are mounted on the shaft for the non-illustrated pulley or pulleys (driven by the motor M7) for the conveyor or conveyors 24e . The idler pulley or pulleys for the conveyor or conveyors 24e are shown at 27 adjacent the magazine 37 for the stack 43 of fully overlapping panels 41a and 41b.
The suction chambers 28 below the upper reaches of the conveyors 24a-24e are connected to an intake of the suction generating device 16 which also serves to evacuate air from the suction chamber 14 (or to a discrete second suction generating device).
A portion of the lower reach of the overhead conveyor 4 is adjacent to a further suction chamber 29 which is connected to the suction generating device 16 or to a discrete suction generating device and is located at a level above the idler pulley or pulleys 23b. The purpose of the suction chamber 29 is to enable the lower reach of the conveyor 4 to attract the developing loops 42 and to push such loops in a direction toward the stacking station 3. The lower reach of the conveyor 4 is in line with the lower reach of a second overhead conveyor 31 which is or can be foraminous and is driven by the motor M2 or by a discrete motor. The shaft 6a for the pulley or pulleys 6 of the conveyor 4 carries the idler pulley or pulleys for the conveyor 31. The motor M2 drives the right-hand pulley or pulleys 32 of the conveyor 31. The transmission between the motor M2 and the pulley or pulleys 32 is or can be such that the speed of the overhead conveyor 31 exceeds the speed of the conveyors 24a-24e but is less than the speed of the conveyors 4 and 7 of the transporting unit 1. In the illustrated apparatus the conveyor 31 is driven at or close to the speed of the conveyor 11, i.e., at a speed less than that of the conveyor 4 but higher than that of the fastest panel-decelerating conveyor (24a) of the series 24.
The apparatus preferably further comprises a loop stabilizing device including one or more nozzles 33 which are connected to the outlet of a source 34 of compressed air or another suitable gaseous fluid and serve to admit jets of compressed gaseous fluid into the loops 42 during advancement of the loops at a level below the overhead conveyor 31 of the diverting unit 2. For example, the loop stabilizing device can comprise two nozzles 33, one at each side of the path which is defined by the conveyors 11, 24a-24e of the diverting path 2, to admit streams of compressed air into the respective open sides of the adjacent loops 42 and to thus ensure that the loops do not collapse while the panels 41b are in the process of catching up with the immediately preceding panels 41a on their way from the ledge 13 toward the magazine 36.
The magazine 36 accumulates a stack 43 of accurately overlapping panels 41a, 41b, and the apparatus further comprises a severing device 37 having a reciprocable and transversely movable sword 38 or another suitable severing tool which penetrates into the stack 43 at predetermined intervals to sever a selected weakened zone 39 and to thus enable the magazine 36 to accumulate a series of stacks 43 each of which contains a predetermined number of overlapping panels. The manner in which the panels of the stack 43 are counted and the manner in which the counter transmits signals to the means for moving the sword 38 into and transversely of the magazine 36 form no part of the present invention.
The mode of operation is as follows:
The conveyors 4 and 7 of the transporting unit 1 move the web 9 in the direction of the arrow 4a whereby successive panels 41a advance toward and over the ledge 13 and are attracted to the upper reach 11a of the conveyor 11 in the diverting unit 2 in response to cyclical lowering of the valving element 17 as a result of rotation of the cam 22 under the action of the shaft 8a. The arrangement is preferably such that the valving element 17 is lowered as soon as the leader of a panel 41a advances to the location 12 immediately downstream of the ledge 13. This entails a deceleration of the panels 41a because the speed of the upper reach 11a is less than the speed of the conveyors 4 and 7. However, the immediately following panels 41b continue to advance at the speed of the conveyors 4, 7 because the lower reach of the conveyor 4 overlies the upper reach 11a of the conveyor 11 so that the panels 41b and/or the adjacent rear portions of the immediately preceding panels 41a develop the respective loops 42 which are attracted to the lower reach of the conveyor 4 during travel along the underside of the suction chamber 29 so that these loops are actually pushed in the direction of the arrow 4a at a speed higher than the speed of the panels 41a adhering to the upper reach 11a of the conveyor 11. The making of loops 42 is desirable and advantageous because they prevent creasing of the web 9 and the formation of an irregular stack of panels in the magazine 36. The suction chamber 29 enables the lower reach of the overhead conveyor 4 to attract the developing loops 42 and to push the loops, and the corresponding panels 41b, in the direction of the arrow 4a at a speed which matches the speed of the conveyor 7 and thus exceeds the speed of the conveyor 11 which latter advances the panels 41a. The feature that the loops 42 are attracted to the lower reach of the conveyor 4 by suction contributes to stability of the loops and further reduces the likelihood of unpredictable folding of the web 9 while its panels advance toward the stacking station 3.
The underside of the lower reach of the overhead conveyor 13 contributes to a continuous increase in the dimensions of the loops 42 which advance at a level above the series 24 of conveyors 24a to 24e. As explained above, the conveyor 32 is driven at the speed of the conveyor 11, i.e., its speed is greater than that of the fastest panel-decelerating conveyor 24a. Consequently, the panels 41b continue to catch up with the immediately preceding panels 41a while such panels advance in the channel between the lower reach of the conveyor 31 on the one hand and the upper reaches of the conveyors 24a to 24e on the other hand. The nozzle or nozzles 33 contribute to desirable stabilization of the loops 42 by admitting a compressed gaseous fluid medium into one or both open sides of each loop in the region above the conveyor 24a. The apparatus can be provided with two or more sets of nozzles, e.g., with a first set above the conveyor 24a, with a second set above the conveyor 24b, and so forth. The cushions of air which develop in the loops 42 stabilize the loops and contribute to predictability of conversion of the web 9 into a stack 43 which is automatically deposited in the magazine 36 and can be expelled, for example, in a direction toward or away from the observer of the drawing. The conveyor 31 cooperates with the loops 42 therebelow to push the corresponding panels 41b toward the stacking station 3 at a speed which exceeds the speed of the conveyors 24a to 24e so that the panels 41b at least nearly completely overlie the immeidately preceding panels 41a not later than at the left-hand side of the magazine 36 but certainly at the time when the panels 41a, 41b are permitted to descend onto the bottom wall of the magazine 36 or onto the panels which are already confined in the magazine.
The conveyor 31 is or can be foraminous, and the apparatus can further comprise one or more suction chambers (not shown) at a level above the lower reach of the conveyor 31 to attract the loops 42 and to even more reliably ensure predictable gradual or stepwise overlapping of each panel 41a by the immediately following panel 41b during travel of such panels from the ledge 13 toward the open upper side of the magazine 36. The need for one or more suction chambers above the lower reach of the conveyor 31 will depend on a variety of parameters, such as the stiffness or lack of stiffness of the web 9, the degree of accuracy with which the panels 41a and 41b are to be stacked on top of each other, and others.
It is further within the purview of the invention to replace the single overhead conveyor 31 with a series of two, three or more discrete conveyors similar to the conveyors 24a to 24e. The conveyors of the series of conveyors which are to replace the conveyor 31 must be driven in such a way that each conveyor of the series advances a loop 42 faster than the conveyor (24a, 24b, 24c, 24d or 24e) therebelow. This ensures predictable advancement of the panels 41b at a speed which exceeds the speed of the immediately preceding panels 41a.
The loops 42 can be formed by the trailing portions of the panels 41a and/or by the leaders of the panels 41b. The valving element 17 and the means for moving this valving element in synchronism with the travel of panels 41a along the path which is defined by the transporting unit 1 ensure that each pair of neighboring panels 41a, 41b develops a loop 42 whose configuration and growth are identical with those of each previously formed loop. The number of conveyors in the series 24 can be increased to such an extent that the panels 41a undergo a practically gradual (rather than a more or less pronounced stepwise) deceleration during travel from the conveyor 11 to the magazine 36. The conveyors 24a to 24e of the series 24 ensure predicatable guidance of the panels 41a all the way from the conveyor 11 to the stacking station 3 and, together with predictable guidance and transport of the panels 41b, ensure the formation of a stack 43 wherein each panel 41b accurately overlies the panel 41a therebelow. The suction chamber 29 and the stabilizing nozzles 33 constitute optional but highly desirable and advantageous features of the improved apparatus. The making of a stack 43 wherein the panels 41a and 41b accurately overlap each other is desirable and advantageous because such stacks can be readily manipulated, e.g., piled on top of additional stacks, wrapped, compacted, etc. The severing device 37 ensures that a continuous stack 43 can be subdivided into smaller stacks each of which contains a preselected number of panels 41a and 41b.
An important advantage of the improved apparatus are its simplicity and compactness. Thus, all that is necessary is to provide a unit which can divert alternate panels (41a) from the path of the web 9 and can predictably decelerate the diverted panels while continuing to advance the non-diverted panels (41b) at the speed of the web 9 or at a speed which can be less than the speed of the web but exceeds the speed of the immediately preceding diverted panels 41a. The various suction chambers and conveyors with means for driving them at selected speeds are components which add little to the complexity of the apparatus but enable the apparatus to zig-zag fold the web 9 with a very high degree of predictability and in a small area. Reliable catching up of the panels 41b with the immediately preceding panels 41a is ensured by the conveyors 24a to 24e and by the overhead conveyor 31. The provision of suction chambers 28, 29 and, if necessary, one or more suction chambers above the lower reach of the conveyor 31, reduces the likelihood of creasing of the web 9 at locations other than the weakened zones 39.
The utilization of conveyors which define substantially horizontal paths for the web 9, for the panels 41a and for the loops 42 contributes to simplicity of the apparatus and ensures that all or nearly all parts of the apparatus are readily accessible.
The improved apparatus can fold a web 9 at a high speed without employing reciprocating, oscillating and/or otherwise moving grippers or analogous parts which are necessary in conventional zig-zag folding apparatus. The utilization of conveyors which define substantially horizontal paths renders it possible to build an apparatus whose height is much less than the height of an apparatus wherein the web is fed vertically downwardly. This simplifies the task of the attendants and contributes to a higher output because the number of down times can be reduced by facilitating convenient access to all parts of the apparatus or, at the very least, to all such parts which are more likely to be contaminated and/or otherwise affected by extensive use. The severing device 37 also contributes to versatility of the apparatus and to convenience of forming stacks containing predetermined numbers of panels.
It is also within the purview of the invention to replace the series of conveyors 24a to 24e with a single conveyor or with a member having a smooth surface or with a plurality of parallel guide rails. This arrangement is especially suitable for folding webs the properties of which ensure the continuation of the catch-up process started by diverting successive panels 41a in the diverting unit 2 only by the motion imparted to the web by the conveyors 4 and 7 and possibly 31.
One embodiment of a suitable severing device 37 is described in U.S. Pat. No. 3,784,188.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims. | A continuous web of paper with a series of transversely extending rows of perforations between successive panels is folded in zig-zag fashion by reducing the speed of each oddly numbered panel and simultaneously diverting the oddly numbered panel from the path of the web while the evenly numbered panels immediately following the diverted oddly numbered panels continue to advance at a higher speed so that the neighboring panels define loops while the next-following evenly numbered panels catch up with the immediately preceding oddly numbered panels. The loops are stabilized by suction-operated conveyors and by admission of compressed air thereinto, and the resulting stack of overlapping panels is severed at intervals across selected rows of perforations to form a series of smaller stacks each of which contains a desired number of panels. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a positive crankcase ventilation (PCV) valve installation structure of a blow-by gas recirculation system provided for an internal combustion engine and, more particularly, to a PCV valve installation structure in an internal combustion engine equipped with an oil cooler device that cools lubricating oil.
[0003] 2. Description of Related Art
[0004] In general, a blow-by gas recirculation system for returning blow-by gas to an intake system is provided for an internal combustion engine (hereinafter, simply referred to as engine) mounted on an automobile, or the like. In addition, there is a V-engine in which cylinder banks are arranged in a V shape centering on a crankshaft as one type of the engine of an automobile. Then, a blow-by gas recirculation system is also provided for the V-engine as well.
[0005] In a related art, there is known a blow-by gas recirculation system that is provided for such a V-engine and in which, as shown in FIG. 7 , PCV valves 100 and 101 are attached to corresponding cylinder head covers 102 and 103 (for example, see Japanese Patent Application Publication No. 2007-224736 (JP-2007-224736)). For example, in a left bank 105 of such a V-engine 104 , an existing blow-by gas recirculation system 106 includes a separator case 107 that is provided for the cylinder head cover 102 and that separates blow-by gas and oil mist from each other, the left PCV valve 100 that emits the blow-by gas separated by the separator case 107 and a left blow-by gas supply tube 108 that couples the left PCV valve 100 to an intake pipe at a portion downstream of a throttle valve. In addition, in a right bank 109 of the V-engine 104 , an existing blow-by gas recirculation system 110 includes a separator case 111 that is provided for the cylinder head cover 103 , the right PCV valve 101 that emits blow-by gas separated by the separator case 111 and a right blow-by gas supply tube 112 that couples the right PCV valve 101 to the intake pipe at a portion downstream of the throttle valve. These two PCV valves 100 and 101 are exposed to an engine room.
[0006] With such a configuration, in the blow-by gas recirculation systems 106 and 110 , for example, when the left PCV valve 100 of the left bank 105 is open and the right PCV valve 101 of the right bank 109 is closed, blow-by gas blown through a gap between a cylinder 113 and a piston 114 into a crank chamber 115 in a compression cycle or expansion cycle of the V-engine 104 is introduced into the separator case 107 via a blow-by gas passage 116 and cam chamber 117 of the left bank 105 . Blow-by gas from which oil mist is separated and removed by the separator case 107 flows out to the left blow-by gas supply tube 108 via the left PCV valve 100 , and is introduced into the intake pipe at a portion downstream of the throttle valve.
[0007] On the other hand, there is suggested a blow-by gas recirculation system that is provided for a V-engine and that has a breather between left and right banks (for example, see Japanese Patent Application Publication No. 2006-70833 (JP-A-2006-70833)). In this blow-by gas recirculation system, blow-by gas that has reached a breather chamber from a crank chamber is separated into gas and liquid in the breather chamber. Then, blow-by gas from which oil mist is separated is emitted through a blow-by gas introducing hole formed above the breather chamber.
[0008] However, in the existing blow-by gas recirculation systems 106 and 110 in which the PCV valves 100 and 101 are respectively provided for the cylinder head covers 102 and 103 as described above, the PCV valves 100 and 101 are exposed to the engine room, and the PCV valves 100 and 101 do not have a heating mechanism, such as a heater, so there is a problem that the PCV valves 100 and 101 may freeze because of running wind while the automobile equipped with the blow-by gas recirculation systems 106 and 110 is running in an environment below freezing. When the PCV valves 100 and 101 freeze, blow-by gas is not emitted from the crank chamber 115 , so degradation of lubricating oil may be facilitated.
[0009] In addition, in the existing blow-by gas recirculation system having the breather chamber between the left and right banks as described above, the PCV valve is assumed to be installed at a blow-by gas introducing hole above the breather chamber, so, as in the case where the PCV valves 100 and 101 are respectively provided for the cylinder head covers 102 and 103 as described above, the PCV valve may freeze because of running wind while an automobile equipped with the blow-by gas recirculation system is running in an environment below freezing.
[0010] On the other hand, in order to prevent freeze of the PCV valve, it is conceivable to provide a heating mechanism, such as a heater, around the PCV valve; however, in this case, the number of components increases to lead to a complex configuration and increased component cost.
SUMMARY OF THE INVENTION
[0011] The invention provides a PCV valve installation structure that is able to efficiently suppress freeze of the PCV valve due to running wind while an automobile is running in an environment below freezing without an increase in the number of components.
[0012] An aspect of the invention relates to a positive crankcase ventilation (PCV) valve installation structure for installing a PCV valve of an internal combustion engine on an engine body. The PCV valve installation structure includes: a blow-by gas recirculation system that includes: a ventilation hose that connects the engine body to an intake device introducing outside air into the engine body and that has a recirculation passage recirculating blow-by gas arising in the engine body to the intake device; and the PCV valve that is installed on the engine body and that opens or closes the recirculation passage of the blow-by gas; a heat exchanger that exchanges heat between lubricating oil and a medium solution that is lower in temperature than the lubricating oil; and a heat transfer portion that transfers heat of the heat exchanger to the PCV valve.
[0013] With the above configuration, while an automobile equipped with the internal combustion engine is running, heat of the heat exchanger is transferred to the PCV valve by the heat transfer portion, so, even when outside air enters an engine room while the automobile is running in an environment below freezing, the possibility that the PCV valve freezes is considerably reduced. By so doing, the PCV valve is hard to freeze in comparison with the structure that the PCV valve is simply installed at an existing cylinder head or between the left and right banks, it is possible to suppress degradation of the lubricating oil when blow-by gas is not emitted because of a clogging due to freeze of the PCV valve. In addition, the heat exchanger of lubricating oil, equipped for the automobile, is used as a heat source, so it is possible to suppress an increase in component cost in comparison with the case where a heater is installed as a new heat source.
[0014] In the PCV valve installation structure according to the above aspect, the heat transfer portion may be a cover of the heat exchanger, and the PCV valve may be installed on the cover. With the above configuration, an additional component other than the existing components does not need to be provided as the heat transfer portion, so it is possible to suppress an increase in the number of components.
[0015] In the PCV valve installation structure according to the above aspect, the PCV valve may be arranged adjacent to the heat exchanger. With the above configuration, in comparison with the case where the PCV valve is located remote from the heat exchanger, it is possible to reduce a heat loss in the heat transfer portion. Thus, it is possible to efficiently suppress freeze of the PCV valve.
[0016] The PCV valve installation structure according to the above aspect may further include an inlet pipe that is arranged near the PCV valve and that flows the lubricating oil into the heat exchanger. With the above configuration, heat of lubricating oil flowing through the inlet pipe is transferred to the PCV valve, so it is possible to suppress freeze of the PCV valve.
[0017] In the PCV valve installation structure according to the above aspect, the heat exchanger may be an oil cooler device, the oil cooler device may include: an oil cooler body that has a wall partitioning an inner side from an outer side and that flows the lubricating oil through the inner side surrounded by the wall; and a water jacket that surrounds the oil cooler body and that flows the medium solution so as to be in contact with the wall of the oil cooler body from the outer side, and heat of the lubricating oil may be transferred to the medium solution via the wall. With the above configuration, the oil cooler device is utilized to make it possible to prevent freeze of the PCV valve.
[0018] In the PCV valve installation structure according to the above aspect, the engine body may be a V-engine having left and right banks, and the heat exchanger and the PCV valve may be arranged between the left and right banks. With the above configuration, the dead space between the left and right banks of the V-engine may be effectively utilized.
[0019] In the PCV valve installation structure according to the above aspect, the PCV valve may be arranged at a rear side of the engine body. With the above configuration, when freezing outside air enters from the front of the engine room, the outside air passes around the engine body and various pipes until the outside air reaches the PCV valve located at the rear side of the engine, so the outside air is heated and exceeds 0° C. when it reaches the PCV valve, so it is possible not to freeze the PCV valve.
[0020] The PCV valve installation structure according to the above aspect may further include: a blow-by gas pressure measuring device that measures an atmospheric pressure of the blow-by gas introduced into the PCV valve; and a determining unit that determines that the PCV valve is clogged when the atmospheric pressure measured by the blow-by gas pressure measuring device is higher than a reference value.
[0021] Another aspect of the invention relates to a positive crankcase ventilation (PCV) valve installation structure for installing a PCV valve of an internal combustion engine on an engine body. The PCV valve installation structure includes: a blow-by gas recirculation system that includes: a ventilation hose that connects the engine body to an intake device introducing outside air into the engine body and that has a recirculation passage recirculating blow-by gas arising in the engine body to the intake device; and the PCV valve that is installed on the engine body and that opens or closes the recirculation passage of the blow-by gas; and a heat exchanger that exchanges heat between lubricating oil and a medium solution that is lower in temperature than the lubricating oil, wherein the PCV valve is arranged adjacent to the heat exchanger.
[0022] Here, in an existing art, work for checking whether the PCV valve remains closed because of freeze or a clogging with sludge, or the like, is, for example, conducted in such a manner that, in the case of the PCV valve formed of a one-way valve, a hose for supplying blow-by gas, which is connected to the PCV valve, is pinched and released during idling of the engine to make determination on the basis of whether the PCV valve gives operating sound like chattering or the PCV valve is removed and then air is blown into or drawn into the PCV valve to determine whether air conducts only in one direction. However, with the above described configuration according to the aspect of the invention, for example, the blow-by gas pressure at which the PCV valve should originally open is set as a reference value. By so doing, when the blow-by gas pressure measuring device detects a blow-by gas pressure that exceeds the reference value, it is possible to detect that there is an abnormal clogging in the PCV valve. Thus, it is possible to easily conduct work for checking for a clogging of the PCV valve.
[0023] According to the aspects of the invention, the heat transfer portion that transfers heat of the heat exchanger to the PCV valve is provided to transfer heat of the heat exchanger to the PCV valve, so it is possible to provide a PCV valve installation structure that is able to efficiently suppress freeze of the PCV valve due to running wind while an automobile is running in an environment below freezing without an increase in the number of components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:
[0025] FIG. 1 is a schematic view of an engine having a PCV valve installation structure according to a first embodiment of the invention;
[0026] FIG. 2 is a schematic plan view of an engine body having the PCV valve installation structure according to the first embodiment of the invention;
[0027] FIG. 3 is an exploded view that shows a blow-by gas recirculation system and oil cooler device that have the PCV valve installation structure according to the first embodiment of the invention;
[0028] FIG. 4 is a cross-sectional view of a cylinder block, taken along the line IV-IV in FIG. 3 ;
[0029] FIG. 5 is a central longitudinal cross-sectional view of a separator case having the PCV valve installation structure according to the first embodiment of the invention;
[0030] FIG. 6 is a schematic view of an engine having a PCV valve installation structure according to a second embodiment of the invention; and
[0031] FIG. 7 is a cross-sectional view of an engine having an existing PCV valve installation structure.
DETAILED DESCRIPTION OF EMBODIMENTS
[0032] Hereinafter, first and second embodiments of the invention will be described with reference to the accompanying drawings. In the first and second embodiments, a PCV valve installation structure according to the aspect of the invention is applied to an engine of an automobile.
First Embodiment
[0033] First, the configuration of the first embodiment will be described. As shown in FIG. 1 and FIG. 2 , an engine 1 is a V-ten gasoline engine that includes a left bank 2 and a right bank 3 . The left bank 2 and the right bank are respectively provided at the left and right sides in a V shape. The engine 1 includes an engine body 4 , an intake device 5 , an exhaust device (not shown), a lubricating device 6 , a cooling device 7 , a blow-by gas recirculation system 8 and an oil cooler device 9 . FIG. 1 is a schematic longitudinal cross-sectional view of the engine body 4 when viewed from its side. FIG. 1 shows five cylinders 11 inside the engine body 4 , and illustrates one of the cylinders 11 at the rear portion of the engine body 4 . However, actually, the cylinders 11 are not installed at the rear portion of the engine body 4 , but, as shown in FIG. 2 , five cylinders 11 are arranged in each of the left and right banks 2 and 3 in the longitudinal direction, and the engine body 4 includes ten cylinders 11 . Each of the cylinders 11 is coupled to the intake device 5 and the exhaust device.
[0034] The engine body 4 includes a cylinder head 14 , a cylinder block 15 , a crankcase 16 , pistons, a crankshaft, connecting rods, an oil pan 17 and a pressure gauge 10 . The pistons are accommodated in the cylinder block 15 . The connecting rods respectively couple the pistons to the crankshaft. The oil pan 17 is provided at the lower portion of the crankcase 16 . The pressure gauge 10 serves as a blow-by gas pressure measuring device and measures the atmospheric pressure inside the crankcase 16 .
[0035] The engine body 4 is mounted on a vehicle body via an engine mount (not shown). In addition, the cylinder head 14 has intake ports 18 , exhaust ports 19 and combustion chambers 20 . The intake ports 18 and the exhaust ports 19 are in communication with the corresponding cylinders 11 . The intake device 5 is connected to the cylinder head 14 , and intake air is supplied to each combustion chamber 20 via the corresponding intake port 18 . In addition, the exhaust device is connected to the cylinder head 14 , and exhaust gas in each combustion chamber 20 is emitted via the corresponding exhaust port 19 .
[0036] The intake device 5 includes an air cleaner 21 , an intake pipe 22 , a throttle valve 23 and intake manifolds 24 . The air cleaner 21 purifies intake air. Intake air from the air cleaner 21 flows through the intake pipe 22 . The throttle valve 23 is provided at a downstream portion of the intake pipe 22 , and adjusts the flow rate of intake air supplied into each combustion chamber 20 . The intake manifolds 24 are connected to the intake pipe 22 to flow intake air into each intake port 18 . In addition, the intake device 5 includes a head intake pipe 25 and a communication passage 26 . The head intake pipe 25 couples the air cleaner 21 to the cylinder head 14 . The communication passage 16 extends from the cylinder head 14 and communicates with the crankcase 16 through the inside of the cylinder block 15 .
[0037] The lubricating device 6 includes a strainer 28 , an oil pump 29 , an oil filter 30 and a flow passage 31 . The strainer 28 is used to draw lubricating oil 27 stored in the oil pan 17 . The oil pump 29 discharges the lubricating oil 27 drawn from the strainer 28 to supply the lubricating oil 27 to the oil cooler device 9 . The oil filter 30 filters the lubricating oil 27 drained from the oil cooler device 9 . The flow passage 31 supplies the filtered lubricating oil 27 to various portions of the engine body 4 . The lubricating path of the lubricating oil 27 starts from the oil pan 17 , passes through the strainer 28 , the oil pump 29 , the oil cooler device 9 , the oil filter 30 and the flow passage 31 , and returns to the oil pan 17 .
[0038] The cooling device 7 includes a coolant pump 32 , cooling passages 33 , a radiator 34 , a thermostat 35 and a heater core 36 . The cooling passages 33 are used to cool various portions of the engine body 4 . The radiator 34 air-cools coolant. When the temperature of the coolant is higher than or equal to a predetermined temperature, the thermostat 35 conducts to flow coolant. The heater core 36 uses coolant heated by the oil cooler device 9 as a heat source. The cooling path of part of coolant starts from the coolant pump 32 , passes through the cooling passages 33 , the radiator 34 and the thermostat 35 , and returns to the coolant pump 32 . In addition, the cooling path of the other part of coolant starts from the coolant pump 32 , passes through the cooling passages 33 , the oil cooler device 9 , the heater core 36 and the thermostat 35 , and returns to the coolant pump 32 .
[0039] Here, in the thermostat 35 , the path from the heater core 36 to the coolant pump 32 is normally open, and the path from the radiator 34 to the coolant pump 32 is opened or closed depending on the temperature of coolant flowing therethrough. That is, when the temperature of coolant is lower than a predetermined value (when the engine is just started), the path from the radiator 34 to the coolant pump 32 is closed to prevent overcooling of coolant. In addition, when the temperature of coolant is higher than the predetermined value (when the engine is sufficiently warmed up), the path from the radiator 34 to the coolant pump 32 is opened to cool coolant by the radiator 34 .
[0040] As shown in FIG. 2 , the blow-by gas recirculation system 8 and the oil cooler device 9 are installed adjacent to each other between the left and right banks 2 and 3 .
[0041] As shown in FIG. 1 and FIG. 2 , the blow-by gas recirculation system 8 includes a PCV chamber 37 , a cover 38 of the PCV chamber 37 , a separator case 39 , PCV valves 41 , ventilation hoses 42 and an oil reservoir 43 . The PCV chamber 37 is formed between the left and right banks 2 and 3 . The separator case 39 is integrated with the cover 38 , and separates blow-by gas and the lubricating oil 27 into gas and liquid. The PCV valves 41 are respectively provided at gas emission ports 40 of the separator case 39 . The ventilation hoses 42 each have a recirculation passage 42 a that couples each PCV valve 41 to the corresponding intake manifold 24 and that recirculates blow-by gas to the corresponding intake manifold 24 . The oil reservoir 43 stores the lubricating oil 27 drained to the PCV chamber 37 and returns the lubricating oil 27 to the oil pan 17 .
[0042] The PCV chamber 37 is a top-open box formed just above the crankcase 16 , and is formed over substantially all the range in the longitudinal direction of the engine body 4 . The cover 38 closes the PCV chamber 37 from the upper side. The separator case 39 is integrally attached to the rear portion on the back side of the cover 38 . As shown in FIG. 5 , a gasket 44 is interposed between the cover 38 and the separator case 39 . An oil recovery hole 45 is provided at the bottom portion of the PCV chamber 37 . The lubricating oil 27 drained from the separator case 39 flows down through the oil recovery hole 45 . The oil reservoir 43 has an upper introducing port 46 and a lower drain port 47 . The oil recovery hole 45 is connected to the introducing port 46 of the oil reservoir 43 . The drain port 47 of the oil reservoir 43 is connected to the crankcase 16 .
[0043] The separator case 39 is surrounded by a front wall 39 a , a bottom wall 39 b , a rear wall 39 c and left and right walls (not shown), and the top of the separator case 39 is hermetically sealed by the cover 38 attached via the gasket 44 . In addition, the separator case 39 has a separator introducing port 48 , a flow passage 49 , the gas emission ports 40 and an oil drain port 50 . The separator introducing port 48 is used to introduce blow-by gas and fresh air. The flow passage 49 flows these gases to separate the gases into gas and liquid. The gas emission ports 40 emit separated blow-by gas and fresh air. The oil drain port 50 drains separated oil. The separator introducing port 48 extends upward as a vertical linear passage configuration so as to penetrate through the cover 38 . The oil drain port 50 is provided at the bottom wall 39 b of the separator case 39 , and extends substantially vertically downward so as to penetrate through the bottom wall 39 b . The gas emission ports 40 extend upward as a vertical linear passage configuration so as to penetrate through the cover 38 .
[0044] The flow passage 49 is defined by a longitudinal plate 51 , a first lateral plate 52 and a second lateral plate 53 . The longitudinal plate 51 faces the front wall 39 a of the separator case 39 and extends downward from the separator introducing port 48 . The first lateral plate 52 faces the bottom wall 39 b of the separator case 39 , and extends rearward from the lower end portion of the longitudinal plate 51 . The second lateral plate 53 faces the upper side of the first lateral plate 52 , and extends forward from the rear wall 39 c of the separator case 39 .
[0045] The flow passage 49 includes a downward passage 54 , a first rearward passage 55 , a forward passage 56 and a second rearward passage 57 . The downward passage 54 extends downward from the separator introducing port 48 between the front wall 39 a of the separator case 39 and the longitudinal plate 51 to the bottom wall 39 b of the separator case 39 . The first rearward passage 55 extends rearward from the lower end portion of the downward passage 54 between the bottom wall 39 b of the case and the first lateral plate 52 to the rear wall 39 c . The forward passage 56 extends upward from the rear end portion of the first rearward passage 55 , turns the direction, and extends forward between the first lateral plate 52 and the second lateral plate 53 to the longitudinal plate 51 . The second rearward passage 57 extends upward from the front end portion of the forward passage 56 , turns the direction, and extends rearward between the cover 39 and the second lateral plate 53 to the two gas emission ports 40 . In this way, the flow passage 49 is narrow and has many short turns, so the misty lubricating oil 47 frequently collides with the longitudinal plate 51 , the first lateral plate 52 , the second lateral plate 53 and the walls 39 a , 39 b and 39 c to thereby efficiently separate and remove oil mist.
[0046] The PCV valves 41 each are formed as a one-way valve that allows blow-by gas and fresh air having a pressure higher than or equal to a predetermined value to flow only in a direction in which gas is emitted through the gas emission ports 40 . In the present embodiment, the two PCV valves 41 are provided on the upper surface of the cover 38 . Then, one of the PCV valves 41 is connected to the intake manifold 24 of the left bank 2 by the ventilation hose 42 , and the other one of the PCV valves 41 is connected to the intake manifold 24 of the right bank 3 by the ventilation hose 42 . In addition, each PCV valve 41 is connected to the corresponding gas emission port 40 having a vertical linear passage configuration from the upper side. Therefore, the PCV valves 41 may be replaced from the upper side of the cover 38 .
[0047] In addition, as shown in FIG. 1 , the separator case 39 and the crankcase 16 are connected by a blow-by gas introducing pipe 58 . By so doing, the separator introducing port 48 is in communication with the inside of the crankcase 16 . Furthermore, the communication passage 26 from the cylinder head 14 to the crankcase 16 is in communication with the separator introducing port 48 by a fresh air introducing pipe 59 . By so doing, fresh air from the communication passage 26 passes through the fresh air introducing pipe 59 and is introduced from the separator introducing port 48 into the separator case 39 to thereby make it possible to push out blow-by gas.
[0048] The recovery path of blow-by gas leaked through a gap between the pistons and the cylinders into the crankcase 16 starts from the cylinder block 15 , passes through the crankcase 16 , the blow-by gas introducing pipe 58 , the separator case 39 , the PCV valves 41 , the intake manifolds 24 and the intake ports 18 , and reaches the combustion chambers 20 .
[0049] As shown in FIG. 3 , the oil cooler device 9 includes an oil cooler body 60 and a water jacket 61 . The oil cooler body 60 has a wall 60 a that partitions an inner side from an outer side. The lubricating oil 27 flows through the inner side surrounded by the wall 60 a . The water jacket 61 surrounds the oil cooler body 60 , and flows coolant so as to be in contact with the wall 60 a of the oil cooler body 60 from the outer side. Then, heat of the lubricating oil 27 is transferred to coolant via the wall 60 a.
[0050] The oil cooler body 60 closely adheres to the back side of the cover 38 via a gasket (not shown). The oil cooler body 60 has an oil introducing port 62 and an oil drain port 63 . The oil introducing port 62 penetrates through the cover 38 and is provided at the rear top portion. The oil drain port 63 penetrates through the cover 38 and is provided at the front top portion. The oil introducing port 62 is connected to the oil pump 29 of the lubricating device 6 by an introducing port-side pipe 64 that serves as an inlet pipe. As shown in FIG. 2 , the introducing port-side pipe 64 is provided so as to pass near the PCV valves 41 above the cover 38 . In addition, the oil drain port 63 is connected to the oil filter 30 of the lubricating device 6 by a drain port-side pipe 65 . These introducing port-side pipe 64 and drain port-side pipe 65 are connected to each other by a by-pass pipe 66 above the cover 38 . A large number of horizontal fin-shaped radiator plates 60 b are formed on the outer side portion of the wall 60 b of the oil cooler body 60 to increase contact area with coolant to thereby enhance the efficiency of heat transfer.
[0051] The water jacket 61 is integrally formed with the PCV chamber 37 , and is formed in a top-open box shape. The water jacket 61 is installed so that the upper end portion closely adheres to the back side of the cover 38 via a gasket 71 . The water jacket 61 has coolant introducing ports 67 and a coolant drain port 68 . The coolant introducing ports 67 are formed at both side portions at the front side of the water jacket 61 . The coolant drain port 68 is provided at the rear side of the water jacket 61 . The coolant introducing ports 67 formed at both side portions are respectively connected to parts of the cooling passages 33 formed in the left and right banks 2 and 3 . In addition, the coolant drain port 68 extends upward through the cover 38 , and is connected to the heater core 36 by a coolant drain pipe 69 . In addition, a spacer 70 is provided between the oil cooler body 60 and the water jacket 61 . The spacer 70 is used to ensure a gap between the outer surface of the oil cooler body 60 and the inner surface of the water jacket 61 .
[0052] Here, a structure for installing the PCV valves 41 in the present embodiment is formed of the blow-by gas recirculation system 8 , the oil cooler device 9 and the cover 38 . These respectively correspond to the blow-by gas recirculation system, the heat exchanger and the heat transfer portion in the PCV valve installation structure according to the aspect of the invention.
[0053] Furthermore, in the present embodiment, the operation of the engine 1 is controlled by an electronic control unit (ECU) (not shown) that serves as a determining unit. In the ECU, a pressure at which the PCV valves 41 open is set to a reference value, the pressure gauge 10 is used to measure the blow-by gas pressure in the crankcase 16 during operation of the engine 1 , and, when it is detected that the internal pressure of the crankcase 16 , that is, the internal pressure of the separator case 39 , is higher than the reference value, it is determined that at least any one of the PCV valves 41 is clogged and is hard to open.
[0054] Subsequently, the procedure of installing the blow-by gas recirculation system 8 and the oil cooler device 9 between the left and right banks 2 and 3 will be described. As shown in FIG. 3 , the separator case 39 and the oil cooler body 60 are assembled to the cover 38 in advance. Then, the cover 38 is attached so that the oil cooler body 60 is placed inside the water jacket 61 in the PCV chamber 37 . By so doing, an assembly of the cover 38 is just installed between the left and right banks 2 and 3 to thereby make it possible to position and install the separator case 39 and the oil cooler body 60 at an appropriate position. Then, the blow-by gas recirculation system 8 and the oil cooler device 9 are piped to other devices.
[0055] Next, the operation of the engine 1 will be described. Dust is removed from intake air by the air cleaner 21 , and the intake air flows from the intake pipe 22 to the intake ports 18 via the throttle valve 23 and the intake manifolds 24 . On the other hand, blow-by gas and fresh air are supplied to the intake manifolds 24 from the blow-by gas recirculation system 8 via the respective ventilation hoses 42 . Therefore, fresh air and blow-by gas are mixedly supplied to the intake ports 18 . The mixed gas is burned in the combustion chambers 20 . In addition, part of unburned gas in the combustion chambers 20 passes around the pistons and flows from the cylinder block 15 into the crankcase 16 .
[0056] On the other hand, part of intake air from the air cleaner 21 passes through the head intake pipe 25 and is supplied to the cylinder head 14 . Intake air is supplied from the cylinder head 14 to the cylinder block 15 and the crankcase 16 via the communication passage 26 . The intake air pushes out blow-by gas inside the cylinder block 15 and the crankcase 16 , and causes the blow-by gas to be introduced into the separator case 39 via the blow-by gas introducing pipe 58 . At this time, part of fresh air taken in through the air cleaner 21 is introduced into the separator case 39 through the path from the cylinder head 14 via the communication passage 26 to the fresh air introducing pipe 59 , and is mixed with blow-by gas.
[0057] Blow-by gas introduced into the separator case 39 contains misty lubricating oil 27 . Therefore, the misty lubricating oil 27 collides with the longitudinal plate 51 , the first lateral plate 52 , the second lateral plate 53 and the walls 39 a , 39 b and 39 c to liquefy inside the separator case 39 , and is drained through the oil drain port 50 provided at the lower portion. The drained lubricating oil 27 is drained through the oil recovery hole 45 at the lower portion of the PCV chamber 37 , and is stored in the oil reservoir 43 . In addition, blow-by gas and fresh air separated by the separator case 39 are released by opening the PCV valves 41 . The released blow-by gas is supplied to the left and right intake manifolds 24 via the corresponding ventilation hoses 42 .
[0058] On the other hand, the lubricating oil 27 stored in the oil pan 17 is drawn and discharged by the oil pump 29 via the strainer 28 . Part of the discharged lubricating oil 27 flows in from the introducing port-side pipe 64 of the oil cooler device 9 , passes through the inside of the oil cooler body 60 and is cooled by coolant, and then flows out from the drain port-side pipe 65 . In addition, the other part of the lubricating oil 27 discharged by the oil pump 29 flows from the introducing port-side pipe 64 to the drain port-side pipe 65 via the by-pass pipe 66 . Here, the introducing port-side pipe 64 passes near the PCV valves 41 , so heat of the lubricating oil 27 is transferred to the PCV valves 41 , and the PCV valves 41 are heated. The lubricating oil 27 drained to the drain port-side pipe 65 is filtered by the oil filter 30 and is supplied to the cylinder block 15 . Then, the lubricating oil 27 of the cylinder block 15 passes through the crankcase 16 and is stored in the oil pan 17 .
[0059] In addition, coolant is discharged from the coolant pump 32 , passes through the cylinder block 15 to cool the cylinder block 15 , and part of the coolant is supplied from the coolant introducing ports 67 of the water jacket 61 of the oil cooler device 9 to the water jacket 61 . By so doing, the lubricating oil 27 that flows through the oil cooler body 60 is water-cooled. Coolant is drained through the coolant drain port 68 of the water jacket 61 , and is supplied to the heater core 36 . Coolant flows through the heater core 36 , passes through the thermostat 35 , and returns to the coolant pump 32 . Here, when the temperature of coolant is lower than a predetermined temperature as in the case of the start of operation of the engine 1 , the path from the radiator 34 to the coolant pump 32 in the thermostat 35 is closed. In addition, when the engine 1 is sufficiently heated and the temperature of coolant is higher than or equal to the predetermined value, the path from the radiator 34 to the coolant pump 32 is opened.
[0060] On the other hand, the other part of coolant that has passed through the cylinder block 15 flows into the radiator 34 . Here, the thermostat 35 is provided downstream of the radiator 34 and coolant flows through the thermostat 35 only when the temperature of coolant is higher than or equal to the predetermined temperature, so coolant flows through the radiator 34 only when the thermostat 35 allows flow of coolant. Coolant that has been cooled by the radiator 34 and that has passed through the thermostat 35 returns to the coolant pump 32 .
[0061] Here, the oil cooler device 9 is operating during operation of the engine 1 , so the heat of the oil cooler device 9 conducts through the cover 38 and reaches the PCV valves 41 . That is, the heat of the oil cooler device 9 is transferred to the portion of the cover 38 at which the oil cooler device 9 is installed, and the heat is transferred therefrom along the cover 38 . Then, the oil cooler device 9 and the separator case 39 are arranged adjacent and close to each other, so the heat of a portion of the cover 38 near the oil cooler device 9 is transferred to the PCV valves 41 with a minimum heat loss to make it possible to heat the PCV valves 41 . Therefore, even when outside air enters an engine room while the automobile is running in an environment below freezing, the possibility that at least any one of the PCV valves 41 freezes may be considerably reduced.
[0062] Here, the pressure at which the PCV valves 41 open is set to a reference value. In this case, when the PCV valves 41 normally operate, the PCV valves 41 open to release blow-by gas in the separator case 39 when the gas pressure of the blow-by gas is higher than the reference value, so the atmospheric pressure of blow-by gas will not be higher than the reference value. In contrast to this, when at least any one of the PCV valves 41 is clogged with sludge, or the like, and is hard to open, the at least any one of the PCV valves 41 does not open even when the atmospheric pressure is higher than the reference value. Therefore, the atmospheric pressure of blow-by gas in the separator case 39 may be considerably higher than the reference value. In addition, the internal pressure of the separator case 39 is equivalent to the internal pressure of the crankcase 16 that is located upstream of the separator case 39 .
[0063] Then, during operation of the engine 1 , the pressure gauge 10 is used to measure the atmospheric pressure of blow-by gas in the crankcase 16 , and, when it is detected that the internal pressure of the crankcase 16 , that is, the internal pressure of the separator case 39 , is higher than the reference value, it may be determined that at least any one of the PCV valves 41 is clogged and is hard to open. Note that the result of determination in the case where at least any one of the PCV valves 41 is hard to open is provided to a driver by a display unit, such as a warning lamp.
[0064] The structure for installing the PCV valves 41 according to the first embodiment is configured as described above, so the following advantageous effects may be obtained.
[0065] That is, during operation of the engine 1 , the heat of the oil cooler device 9 conducts through the cover 38 and reaches the PCV valves 41 , and the heat of the introducing port-side pipe 64 reaches the PCV valves 41 on the cover 38 , so, even when outside air enters the engine room while the automobile equipped with the engine 1 is running in an environment below freezing, the possibility that at least any one of the PCV valves 41 freezes may be considerably reduced. By so doing, the PCV valves 41 are hard to freeze in comparison with the structure that the PCV valves 41 are simply installed at an existing cylinder head or between the left and right banks 2 and 3 , it is possible to suppress degradation of the lubricating oil 27 when blow-by gas is not emitted because of a clogging of the PCV valves 41 . In addition, the oil cooler device 9 equipped for the automobile is used as a heat source, so it is possible to suppress an increase in component cost in comparison with the case where a heater is installed as a new heat source.
[0066] Furthermore, the PCV valves 41 are provided adjacent to the oil cooler device 9 , so it is possible to reduce a heat loss in the cover 38 in comparison with the case where the PCV valves 41 are provided remote from the oil cooler device 9 , and it is possible to further effectively suppress freeze of the PCV valves 41 . Moreover, the PCV valves 41 are arranged at the rear side of the engine body 4 , so, when freezing outside air enters from the front of the engine room, the outside air passes around the engine body 4 and various pipes until the outside air reaches the PCV valves 41 located at the rear side of the engine 1 . Therefore, outside air is heated and exceeds 0° C. when it reaches the PCV valves 41 , so it is possible not to freeze the PCV valves 41 .
[0067] In addition, the atmospheric pressure of blow-by gas in the crankcase 16 is measured to make it possible to detect a clogging of at least any one of the PCV valves 41 , so it is possible to considerably easily conduct checking work for the PCV valves 41 , such as not only checking for a frozen PCV valve 41 but also whether at least any one of the PCV valves 41 is clogged with sludge.
[0068] Moreover, the PCV valves 41 are installed on the cover 38 between the left and right banks 2 and 3 so as to be replaceable from the upper side, so it is possible to easily replace the PCV valves 41 in comparison with the case where a PCV valve is provided at a portion that is hidden by another cover, or the like, or an inaccessible portion and work for detaching another member is, for example, required in order to replace the PCV valve. Thus, it is possible to considerably easily conduct checking work for the PCV valves 41 in such a manner that the pressure gauge 10 is used to measure the atmospheric pressure of blow-by gas in the crankcase 16 , and, if it is detected that at least any one of the PCV valves 41 is clogged as a result of checking, it is possible to easily replace the at least any one of the PCV valves 41 .
[0069] In addition, the separator introducing port 48 is formed as a vertical linear passage configuration that penetrates through the cover 38 , so it is possible to effectively utilize dead space in comparison with the case where the separator introducing port 48 is formed as a configuration that extends in another direction. Furthermore, the blow-by gas recirculation system 8 and the oil cooler device 9 are provided between the left and right banks 2 and 3 , so it is possible to effectively utilize the dead space of the V-engine.
Second Embodiment
[0070] In an engine 1 according to a second embodiment, a dry sump is employed. Therefore, the oil pan 17 formed in the crankcase 16 according to the first embodiment differs from that of the second embodiment; however, the other components are similarly configured. Thus, the same components as those of the first embodiment shown in FIG. 1 to FIG. 5 will be described using like reference numerals, and the difference will be specifically described in detail.
[0071] As shown in FIG. 6 , a partition plate 80 is provided at the lower portion of the crankcase 16 for each cylinder 11 . Each of the bottom portions of spaces partitioned by the partition plates 80 has a suction hole 81 . Furthermore, each suction hole 81 is connected to a scavenge pump 82 . The scavenge pump 82 is used to draw blow-by gas and fresh air in the crankcase 16 and lubricating oil stored at the bottom portion. At this time, the bottom portion of the crankcase 16 is partitioned by the partition plates 80 , so lubricating oil may be efficiently drawn even when a lateral load is applied to the engine 1 . These blow-by gas, fresh air and oil are stored in an oil tank 83 from the scavenge pump 82 .
[0072] The oil tank 83 has a gas emission port 84 formed at an upper portion and an oil drain port 85 formed at a lower portion. The gas emission port 84 is connected to the separator introducing port 48 of the separator case 39 by the blow-by gas introducing pipe 58 . Therefore, blow-by gas and fresh air pushed out through the gas emission port 84 are introduced into the separator case 39 .
[0073] Furthermore, a pressure gauge 86 is provided for the oil tank 83 . The pressure gauge 86 is used to measure the internal atmospheric pressure. The internal pressure of the separator case 39 is equivalent to the internal pressure of the oil tank 83 that is located upstream of the separator case 39 . Therefore, the pressure gauge 86 is used to measure the atmospheric pressure of blow-by gas in the oil tank 83 to thereby make it possible to measure the internal pressure of the separator case 39 . By so doing, it is possible to determine whether at least any one of the PCV valves 41 is clogged and is hard to open.
[0074] In the present embodiment, the lubricating device 6 includes the oil tank 83 , the oil pump 87 , the oil filter 30 , the flow passage 31 and the scavenge pump 82 . The oil tank 83 is provided outside the engine body 4 . The oil pump 86 discharges lubricating oil supplied from the oil tank 83 and supplies the lubricating oil to the oil cooler device 9 . The oil filter 30 filters the lubricating oil drained from the oil cooler device 9 . The flow passage 31 supplies the filtered lubricating oil to various portions in the engine body 4 . The scavenge pump 82 draws lubricating oil stored at the bottom portion of the crankcase 16 . The lubricating path starts from the oil tank 83 , passes through the oil pump 87 , the oil cooler device 9 , the oil filter 30 , the flow passage 31 , the crankcase 16 and the scavenge pump 82 , and returns to the oil tank 83 .
[0075] Blow-by gas arises in the combustion chambers 20 . The recovery path of the blow-by gas starts from the combustion chambers 20 , and passes through the cylinder block 15 , the crankcase 16 , the scavenge pump 82 , the oil tank 83 , the separator case 39 , the PCV valves 41 , the intake manifolds 24 , the intake ports 18 , and returns to the combustion chambers 20 .
[0076] In addition, the communication passage 26 from the cylinder head 14 to the crankcase 16 is directly connected to the scavenge pump 82 . Furthermore, separately from the communication passage 26 , a fresh air introducing passage 88 that couples the cylinder head 14 to the scavenge pump 82 is provided. By so doing, a large amount of fresh air may be introduced from the scavenge pump 82 into the oil tank 83 .
[0077] The structure for installing the PCV valves 41 according to the second embodiment is configured as described above, so the following advantageous effects may be obtained.
[0078] That is, because the dry sump is employed as described above, lubricating oil may be stably stored in the oil tank 83 , a friction loss may be reduced, for example, biasing or foaming of lubricating oil in the crankcase 16 may be prevented, and lubricating oil may be stably supplied to lubricated portions of the engine body 4 .
[0079] In addition, as in the case of the first embodiment, during operation of the engine 1 , the heat of the oil cooler device 9 conducts through the cover 38 and reaches the PCV valves 41 , and the heat of the introducing port-side pipe 64 reaches the PCV valves 41 on the cover 38 , so, even when outside air enters the engine room while the automobile equipped with the engine 1 is running in an environment below freezing, the possibility that at least any one of the PCV valves 41 freezes may be considerably reduced.
[0080] Furthermore, the PCV valves 41 are provided adjacent to the oil cooler device 9 , so it is possible to reduce a heat loss in the cover 38 in comparison with the case where the PCV valves 41 are provided remote from the oil cooler device 9 , and it is possible to further effectively suppress freeze of the PCV valves 41 .
[0081] In addition, the atmospheric pressure of blow-by gas in the crankcase 16 is measured to make it possible to detect a clogging of at least any one of the PCV valves 41 , so it is possible to considerably easily conduct checking work for the PCV valves 41 , such as not only checking for a frozen PCV valve 41 but also whether at least any one of the PCV valves 41 is clogged with sludge. Moreover, the PCV valves 41 are installed on the cover 38 between the left and right banks 2 and 3 so as to be replaceable from the upper side, so it is possible to easily replace the PCV valves 41 .
[0082] Here, in the above described structures for installing the PCV valves 41 according to the first and second embodiments, the PCV valves 41 are installed at the rear portion of the engine body 4 ; instead, in the PCV valve installation structure according to the aspect of the invention, the position at which the PCV valves 41 are installed may be another portion, and may be, for example, at the front portion or center portion of the engine body 4 .
[0083] In addition, in the structures for installing the PCV valves 41 according to the first and second embodiments, each PCV valve 41 is formed of a one-way valve; however, in the PCV valve installation structure according to the aspect of the invention, each of the PCV valves 41 is not limited to a mechanical one-way valve. Each of the PCV valves 41 may be an electromagnetic valve that may be electrically controlled to open or close or that is able to electrically control the flow rate.
[0084] In addition, in the structures for installing the PCV valves 41 according to the first and second embodiments, the pressure gauge 10 or 86 is used to detect whether at least any one of the PCV valves 41 is hard to open; instead, in the PCV valve installation structure according to the aspect of the invention, the pressure gauge 10 or 86 may be omitted.
[0085] Furthermore, in the structures for installing the PCV valves 41 according to the first and second embodiments, the engine 1 is of a V-ten type; instead, in the PCV valve installation structure according to the aspect of the invention, the engine 1 may be of another type, and may be, for example, of a V-six type, a V-eight type or an in-line type other than a V type. When the engine 1 is of an in-line type, there is no space between the banks 2 and 3 as described in the present embodiments, so, for example, a blow-by gas recirculation system and an oil cooler device are installed at a side portion of an engine body, or the like.
[0086] As described above, the PCV valve installation structure according to the aspect of the invention is able to prevent freeze of the PCV valve at low cost without providing another member, such as a heater, even when freezing outside air blows into an engine room, and is useful in all the PCV valve installation structures suitable for the case where an automobile used in cold climate areas includes a blow-by gas recirculation system. | A positive crankcase ventilation (PCV) valve installation structure for installing a PCV valve of an engine on an engine body includes: a blow-by gas recirculation system that includes a ventilation hose that connects the engine body to an intake device introducing outside air into the engine body and that has a recirculation passage recirculating blow-by gas arising in the engine body to the intake device and an oil cooler device that exchanges heat between lubricating oil and a medium solution that is lower in temperature than the lubricating oil; and a cover that transfers heat of the oil cooler device to the PCV valve. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 10/892,804, filed on Jul. 16, 2004 now U.S. Pat. No. 7,145,782.
BACKGROUND
The present invention relates to voltage regulators (VRs), and more specifically to placement of VR components in a system.
Voltage regulators are used in systems such as a personal computer (PC) (e.g., a desktop computer, server computer, notebook computer and the like) to receive input direct current (DC) voltages of a given voltage and convert and regulate such DC voltages to one or more regulated voltage levels required by various system components, such as integrated circuits (ICs) and the like.
In a typical system, for example, a desktop PC, a motherboard is used to support various system components, including ICs, connectors, VR components, and the like. Such VR components may include output inductors, bulk capacitors, metal oxide silicon field effect transistors (MOSFETs), driver ICs, and the like. Typically, the VR components are placed on a primary side (e.g., a topside) of the motherboard. These VR components must be placed outside an IC device's keepout zone (i.e., the IC's footprint, including any socket or heatsink retention). This placement can result in larger loadline lengths and therefore higher loadline impedance (i.e., capacitance, inductance, and resistance). In such manner, VR components may be located many centimeters away from an intended load (e.g., an IC). Accordingly, motherboard/package lateral travel dominates, increasing loadline length and therefore impedance.
Instead of the above described placement of VR components, other systems use some type of additional VR daughter module (i.e., a separate circuit board) that is plugged into the motherboard or an IC device. However, such additional circuit boards increase cost and complexity, and further increase the size of a given form factor. Furthermore, such designs typically provide inferior performance. A need thus exists to provide VR components that have reduced loadline length and impedance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a circuit board of a system in accordance with one embodiment of the present invention.
FIG. 2 is a plan view of a layout of a circuit board having an integrated circuit and voltage regulator components in accordance with one embodiment of the present invention.
FIG. 3 is a close-up view of a portion of the circuit board of FIG. 2 .
DETAILED DESCRIPTION
In various embodiments of the present invention, different components of a voltage regulator may be coupled to a secondary side of a circuit board, such as a motherboard. More specifically, such components may be placed within a keepout zone of an IC located on the primary side of the circuit board. For example, a processor of a system may be coupled to a motherboard by a socket. Such a socket may have a keepout zone associated therewith on the primary side that prevents any other component from being located within the keepout zone. Thus, by locating one or more voltage regulator components on a secondary side of the circuit board, such components may be located closer to their load (i.e., the microprocessor) than if the components were located on the primary side of the circuit board. In such manner, a substantially shorter loadline and therefore a smaller loadline impedance may be accommodated.
While the types of components that may be placed on the secondary side may vary, in certain embodiments such components may include output inductors, board bulk and high-frequency (HF) capacitors, and one or more MOSFETs. Such location of voltage regulator components may improve current and voltage transients, provide for better power delivery efficiency, and lower operating temperatures for a voltage regulator. Furthermore, such location may also enable operation at higher current levels. Further, by providing such components on a secondary side of a circuit board, additional space may be open on the primary side, which either frees up space or permits use of a smaller circuit board to support all desired components.
Referring now to FIG. 1 , shown is a cross-sectional view of a circuit board of a system in accordance with one embodiment of the present invention. As shown in FIG. 1 , circuit board 20 may support multiple components. As shown in FIG. 1 , some components may be surface mounted onto the circuit board, while others may be mounted by use of conductive through-holes within the circuit board. Circuit board 20 may be any desired circuit board, such as a motherboard of a PC. For example, circuit board 20 may be a four-layer motherboard for a desktop computer, although the scope of the present invention is not so limited.
As shown in FIG. 1 , a primary side (i.e., the upper side) of circuit board 20 supports a semiconductor device 30 (also referred to herein as “IC 30 ”), which may be coupled to circuit board 20 via a package 35 . Package 35 may provide connections to pins of semiconductor device 30 . In one embodiment, semiconductor device 30 may be a microprocessor, such as a central processing unit (CPU) of the system. In turn, package 35 may be coupled to a socket 38 that may be formed of a housing that includes conductors to couple connections from semiconductor device 30 to connections on circuit board 20 .
An integrated heat spreader 37 may be mounted to package 35 (e.g., via an epoxy) and coupled to semiconductor device 30 to aid in cooling. In turn, a heat sink (not shown in FIG. 1 ) may be coupled to integrated heat spreader 37 to provide heat dissipation. Such a heat sink may provide retentions to circuit board 20 . As shown in FIG. 1 , package 35 may form a keepout zone. That is, the dimensions of package 35 define an area within which components typically cannot be mounted on circuit board 20 .
To reduce loadline impedance and provide better voltage regulator operation, multiple voltage regulation components may be coupled to a secondary side (i.e., the lower side) of circuit board 20 . As shown in FIG. 1 , such components may include a plurality of bulk capacitors 41 and a plurality of output inductors 46 . Collectively, capacitors 41 and inductors 46 may form one or more output inductor-capacitor (LC) filters used as output filters for a voltage regulator. Such a voltage regulator may be a single regulator with multiple phases. In other embodiments, multiple regulators may be present, each having multiple phases. In certain embodiments, such an LC filter may be located directly under semiconductor device 30 and may provide a relatively short low impedance path to the load. In some embodiments such an impedance path may be only a few millimeters, for example, between two and five millimeters.
Further shown in FIG. 1 , the secondary side of circuit board 20 may support multiple MOSFETs 51 b . In certain embodiments, MOSFETs 51 b may act as synchronous FETs (SYNC FETs) that may be used in setting up and controlling a pulse width modulation (PWM) of the voltage regulator. While these secondary side components are shown for purposes of illustration in FIG. 1 , it is to be understood that in other embodiments more, fewer or different components may be located on a secondary side of a circuit board and substantially within or near a keepout zone of an IC on the primary side.
Still referring to FIG. 1 , additional components may be located on the primary side of circuit board 20 . Such components may include a plurality of HF capacitors 44 that may act as decoupling capacitors. Further, a plurality of MOSFETs 51 a may be located at an immediate periphery of package 35 . Such MOSFETs 51 a may be control FETs (CTRL FETs) used in controlling the PWM of the voltage regulator. Further components may include bulk capacitors 55 a and 55 b that may be used to filter incoming unregulated voltages to circuit board 20 .
In other embodiments, SYNC FETs 51 b maybe on the primary side of a circuit board and CTRL FETs 51 a may be on the secondary side. In still other embodiments, both types of FETs may be present on a secondary side of a circuit board.
Further shown in FIG. 1 is a connector 60 that is coupled to receive one or more source voltages, for example, from a power supply of the system. Such voltages may then be converted to voltages used by components on circuit board 20 . For example, a 12 volt level may be converted to a lower voltage, such as a 1.3 or 0.9 volt level used by a microprocessor.
Referring now to FIG. 2 , shown is a plan view of a layout of a circuit board having an integrated circuit and voltage regulator components in accordance with one embodiment of the present invention. In the embodiment of FIG. 2 , the VR components may be associated with a multiple phase voltage regulator, and more specifically a six-phase regulator, although the scope of the present invention is not so limited.
As shown in FIG. 2 , IC 30 may be mounted to package 35 , which in turn maybe mounted via a socket (not shown in FIG. 2 ) and a retention mechanism 36 to a top side of a circuit board 20 . Interconnects of IC 30 may form a pin field within the boundaries of IC 30 . IC 30 may have packaging in accordance with a land grid array (LGA) type package, although the scope of the present invention is not so limited. For example, in other embodiments, a ball grid array (BGA) package or a pin grid array (PGA) package may be used. The term “pin” is used herein to refer to any type of interconnect, and it is to be understood that such interconnects may be pins, balls, pads or other types of interconnects, in different embodiments.
Still referring to FIG. 2 , IC 30 may be supported and coupled to a package 35 that in turn is coupled via board retention 36 to circuit board 20 . While not shown in FIG. 2 , it is to be understood that an integrated heat spreader may support heat sink and other thermomechanical components.
As shown in FIG. 2 , various voltage regulator components may be positioned on a secondary side of motherboard 20 , and certain of these components may be located within the keepout zone of package 35 . For example, a plurality of synchronous MOSFETs 51 b may be located on the secondary side. Furthermore, a plurality of output inductors may be located on the secondary side at a substantial periphery of pin field 33 . Note for ease of illustration only pads of a single inductor 46 is shown in FIG. 2 . Furthermore, bulk capacitors 41 may be coupled to the secondary side. As shown, bulk capacitors 41 may be located directly underneath IC 30 but outside of its pin field, in the embodiment of FIG. 2 . Such bulk capacitor placement in general may improve VR stability.
Additional voltage regulator components that may be located on the secondary side may include a plurality of HF decoupling capacitors, one of which is shown in FIG. 2 as HF capacitor 43 . As will be discussed below, such capacitors may be positioned between multiple planes of circuit board 20 . Additional HF capacitors 44 may be coupled to a primary side of circuit board 20 . Specifically, as shown in FIG. 2 , primary side HF capacitors 44 may be located directly under the pin field (and substantially in the middle thereof), and in an unpopulated portion of the pin field.
Other voltage regulator components may be coupled to the primary side of circuit board 20 . Such components may include a plurality of CTRL MOSFETs 51 a , which may be coupled just outside a keepout zone of package 35 . As shown, such CTRL MOSFETs 51 a may be located substantially adjacent to SYNC MOSFETs 51 b (although on the other side of circuit board 20 ).
Further shown in FIG. 2 are shaded regions corresponding to different planes of circuit board 20 . Such planes may be various layers of circuit board 20 and corresponding interconnects of the pin field. While referred to herein as “planes” of circuit board 20 , it is to be understood that such planes have corresponding areas in the pin field. As shown in FIG. 2 , such planes may include a PWM plane 21 that may be used to couple CTRL MOSFETs 51 a to corresponding SYNC MOSFETs 51 b , a ground plane 22 and a Vcc plane 23 (i.e., a supply voltage plane). As shown in FIG. 2 , PWM plane 21 may have an area that extends from a periphery of ground area 22 to couple SYNC MOSFETs 51 b to CTRL MOSFETs 51 a.
As shown in FIG. 2 , the pin field may be formed of highly consolidated power and ground areas with substantial crenellations therebetween. Ground plane 22 may be situated substantially around a periphery of the pin field of IC 30 . Ground plane 22 may have a plurality of crenellations formed therein that provide extensions to abut portions of PWM plane 21 on a peripheral side, and on a proximal side such crenellations may abut a similar crenellated pattern of Vcc plane 23 . In such manner, ground plane 22 acts as an intermediate area between Vcc plane 23 and PWM plane 21 , and ground plane 22 acts as a moat around Vcc plane 23 .
In one embodiment, output inductors may have dimensions of approximately 0.25 inches by 0.25 inches, although the scope of the present invention is not so limited. As shown in FIG. 2 (and in a close-up in FIG. 3 ), in such an embodiment a PWM side inductor 146 (in FIG. 2 ) sits just outside pin field 33 , while a Vcc side inductor 46 (in FIG. 2 ) sits within pin field 33 . The crenellations provide a connection to such inductors and also provide a better opportunity to place HF decoupling capacitors directly between the Vcc input and the ground return planes.
Still referring to FIG. 2 , the overall VR loadline may be reduced by placing SYNC FETs 51 b on the secondary side within the keepout zone of package 35 . Since the socket to SYNC FET conduction path should carry roughly as much current as the Vcc line, such placement may have a substantial impact on reducing the overall loadline. Due to space constraints, this embodiment may place CTRL FETs 51 a on the primary side outside the socket keepout zone, although the scope of the present invention is not so limited.
Referring now to FIG. 3 , shown is a plan view of circuit board 20 of FIG. 2 and components attached thereto. More specifically, FIG. 3 is a close-up of the embodiment of FIG. 2 . FIG. 3 shows in more detail a portion of the crenellation pattern between Vcc plane 23 and ground plane 22 . As shown in FIG. 3 , the crenellations may be of a substantially identical depth and width. While shown in the embodiment of FIG. 3 as being four socket pins deep and four (and five) socket pins wide, it is to be understood that the scope of the present invention is not so limited, and different crenellation patterns may be present in different embodiments. As shown in FIG. 3 , the pin field may be formed of a plurality of primary side socket pins 36 (one of which is designated reference number 36 in FIG. 3 ).
Also shown in FIG. 3 are various voltage regulator components coupled to both the primary and secondary sides of circuit board 20 . The primary side components include HF capacitors 44 within Vcc plane 23 . Secondary side components include HF capacitors 43 which as shown, are located between Vcc plane 23 and ground plane 22 . Placement of the HF capacitors within the pin field may improve performance by lowering the capacitors' parasitic loadline. Similarly, output inductors 47 (one of which is shown for illustration in FIG. 3 ) may be located such that a PWM side inductor pad 46 a is located just outside of the pin field, while the Vcc side inductor pad 46 b sits within the pin field, and more specifically within Vcc area 23 . Note pads 46 a and b are shown coupled to a top inductor in FIG. 3 .
Thus by placing key VR components on the motherboard's secondary side, VR components may be located substantially underneath an IC device. As a result, the loadline length may be significantly shorter, resulting in a substantial drop in loadline impedance from the VR to the IC device. This reduction may result in better current and voltage transients, better power delivery efficiency and lower VR temperatures. It may also help enable higher current levels (e.g., approximately 150 amperes and more, in certain embodiments).
Also, in systems where form factor is important, VR component placement in accordance with an embodiment of the present invention may free up more motherboard space, due to the movement of key VR components to the secondary side and underneath the socket keep-out.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention. | In one embodiment, the present invention includes a method of mounting a semiconductor device to a first side of a circuit board; and mounting at least one voltage regulator device to a second side of the circuit board, the second side opposite to the first side. The voltage regulator devices may be output filters, inductors, capacitors, and the like. In certain embodiments, the devices may be located directly underneath the semiconductor device. | 8 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 09/421,504, filed on Oct. 20, 1999 U.S. Pat. No. 6,434,910, which claims priority from U.S. Provisional Patent Application Ser. No. 60/115,953 filed on Jan. 14, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an insulated glass assembly and, in particular, to core spacers separating glass panes.
2. Description of the Related Art
Insulating glass is usually made of at least two panes adhered together along their edges by a core spacer. In the prior art, there are several types of core spacers manufactured from synthetic foam which is soft and easily compressed. Exemplary is the spacer shown in U.S. Pat. No. 5,806,272 which was issued to Lafond on Sept. 15, 1998.
However, such foam core spacers have minimal stability because of their easy compressibility. Furthermore, such foam spacers are readily stretched longitudinally, thus allowing them to be deformed or broken apart before, during or after installation in a window frame.
Another disadvantage of foam core spacers is that they often interact chemically with hot melt butyl, thus causing a stain discoloration which is unacceptable aesthetically. Such a chemical reaction further frequently causes a variety of other problems, like a change in adhesion strength, a shrinkage of the foam spacer, or an expansion thereof. Whenever a shrinkage occurs, the spacer tends to pull away from the corners where the glass panes are joined together. Likewise, if an expansion occurs, the foam spacer becomes misshapen and appears unattractive.
SUMMARY OF THE INVENTION
A solid EPDM rubber core spacer is provided with a centrally positioned, nonstretchable cord made of fiberglass or similar material for imparting strength thereto. Furthermore, the EPDM rubber formulation is chemically compatible with hot melt butyl which is used as an adhesive and as a moisture vapor barrier. Although there are many differences between the hot melt butyls manufactured by different companies, it is important to formulate an EPDM rubber which ensures chemical compatibility.
A key advantage of the present invention is improved stability over foam core spacers when in compression during oven pressing, packing, shipping, and installing in windows. In each situation, the solid rubber core spacer undergoes significantly less compression than the foam of the prior art spacers.
Another advantage of the present invention is the incorporation of the fiberglass cord into the rubber core spacer so that no stretching of the spacer occurs during initial manufacture, spacer assembly, coiling of the spacer, and application of the finished spacer between two glass panes. Also, heating and cooling of the spacer does not result in any deformation or breakage of the spacer when in use because of the presence of the continuous nonstretchable fiberglass cord incorporated therein. Of course, in the real world, everything can be stretched to a breaking point if a powerful enough pulling force is exerted. In that sense, the fiberglass cord is nonstretchable under normal conditions of use.
A further advantage of the present invention is that the chemical composition of the EPDM rubber in the core spacer is such that it does not react, other than in a minimally inconsequential way, with hot melt butyl. Thus, this feature of the present invention prevents a chemical reaction that could cause a stain discoloration, a change of adhesion strength, shrinkage, expansion or any other disadvantage inherent in the prior art foam core spacers whenever a chemical reaction takes place.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first embodiment of the present invention.
FIG. 2 is a side elevational view of the first embodiment.
FIG. 3 is an exploded side elevational view of a second embodiment.
FIG. 4 a is a side elevational view of a third embodiment.
FIG. 4 b is a side elevational view of a fourth embodiment.
FIG. 4 c is a side elevational view of a fifth embodiment.
FIG. 4 d is a side elevational view of a sixth embodiment.
FIG. 4 e is a side elevational view of a seventh embodiment.
FIG. 4 f is a side elevational view of an eighth embodiment.
FIG. 4 g is a side elevational view of a ninth embodiment.
FIG. 4 h is a side elevational view of a tenth embodiment.
FIG. 4 i is a side elevational view of an eleventh embodiment.
FIG. 5 is an exploded side elevational view of a twelfth embodiment.
FIG. 6 is a perspective view of the first embodiment.
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, a first embodiment of a rubber core spacer 10 , noncircular in shape, is shown with a top side 12 , a bottom side 14 , a short side 16 , a long side 18 , and two diagonally cut corners 20 and 22 . A single, nonheating, nonstretchable, centrally positioned fiberglass cord 24 is embedded in the rubber core spacer 10 when the latter is manufactured so that the core spacer 10 is not stretchable. The preferred rubber formulation for the spacer 10 is an ethylene propylene diene monomer (EPDM) polymer with fillers. However, other solid rubber materials may be suitable.
The height H varies according to the width selected for the spacer 10 . Thus, the height H may range from as little as one quarter to three quarters of an inch or greater.
The cord 24 is cylindrical in shape and has a diameter of at least 0.01 inch which is sufficient for the cord 24 to be effective inside the spacer 10 . However, the preferred diameter is 0.02 inch. In FIG. 1, it can be seen that the cord 24 has its diameter no greater than about 10% of the width of the spacer 10 .
In FIG. 2, a first hot butyl melt adhesive 26 is applied around at least two sides, but preferably the three sides 12 , 14 , 16 and the corners 20 and 22 of the core spacer 10 , although it is sufficient to be applied around only the top side 12 and the bottom side 14 . This first adhesive 26 sticks the core spacer 10 between a pair composed of a top glass pane 32 and a bottom glass pane 34 . These glass panes 32 and 34 are flat sheets that are parallel to each other. After the first adhesive 26 is positioned, a desiccant 38 is arranged adjacent to the core spacer 10 and is spaced between the pair of parallel panes 32 and 34 by a second hot butyl melt adhesive 28 which is applied around at least two sides and preferably three sides of the desiccant 38 to hold the desiccant 38 between the pair of parallel panes 32 and 34 . This desiccant 38 is a drying agent intended to absorb any moisture between the panes 32 and 34 and is open on one side 40 to the space separating the panes 32 and 34 . Desiccants are well known in the prior art and many types may be suitable.
In FIG. 3, a second embodiment is shown in an exploded view in which the desiccant 38 has cut corners 46 and 48 to help the second adhesive 28 hold a vapor barrier 30 in place between the core spacer 10 and the desiccant 38 . The vapor barrier 30 may be a metallized plastic film embedded at both ends in the second adhesive 28 . The core spacer 10 remains in the same position, surrounded on all sides, except for the long side 18 , by the first adhesive 26 . The two panes 32 and 34 , as in the first embodiment seen in FIGS. 1 and 2, are held apart by the core spacer 10 while the desiccant 38 absorbs any moisture in the space therebetween.
In FIG. 4 a, a third embodiment is shown in which the spacer 10 has its corners 20 a and 22 a cut longer than the corners 20 and 22 seen in the first embodiment of FIGS. 1 and 2.
In FIG. 4 b, a fourth embodiment is shown in which corners 20 b and 22 b of the spacer 10 come to a point 16 b instead of to the side 16 , as seen in the first embodiment of FIGS. 1-2.
FIGS. 4 c through 4 g show further embodiments in which patterns are cut into the top side 12 and the bottom side 14 of the spacer 10 to form voids for a purpose to be described.
In FIG. 4 c, a fifth embodiment is shown in which the spacer 10 has triangular indentations 12 c and 14 c in the top side 12 and the bottom side 14 , respectively.
In FIG. 4 d, a sixth embodiment is shown in which the spacer 10 has a plurality of serrated teeth 12 d and 14 d in the top side 12 and the bottom side 14 , respectively.
In FIG. 4 e, a seventh embodiment is shown in which the spacer 10 has scalloped recesses 12 e and 14 e in the top side 12 and the bottom side 14 , respectively.
In FIG. 4 f, an eighth embodiment is shown in which the spacer 10 has deep grooves 12 f and 14 f in the top side 12 and the bottom side 14 , respectively.
In FIG. 4 g, a ninth embodiment is shown in which the spacer 10 has a plurality of shallow channels 12 g and 14 g in the top side 12 and the bottom side 14 , respectively.
In FIG. 4 h, a tenth embodiment is shown in which the spacer 10 has wide depressions 12 h and 14 h in the top side 12 and the bottom side 14 , respectively. However, unlike the embodiments shown in FIGS. 4 a through 4 g, the spacer 10 in FIG. 4 h does not have any cut diagonal corners.
The purpose of the indentations 12 c and 14 c in FIG. 4 c, the teeth 12 d and 14 d in FIG. 4 d, the recesses 12 e and 14 e in FIG. 4 e, the grooves 12 f and 14 f in FIG. 4 f, the channels 12 g and 14 g in FIG. 4 g, and the depressions 12 h and 14 h in FIG. 4 h, is to allow the first adhesive 26 illustrated in FIGS. 1-3 to fill the voids therein so that the adhesive 26 sticks better to the spacer 10 and to the glass panes 32 and 34 of FIGS. 1-3.
In FIG. 4 i, an eleventh embodiment is shown in which the spacer 10 has a rectangular cross section through which the cord 24 is centrally positioned. Note that there are no diagonally cut corners and no indentations.
In FIG. 5, a twelfth embodiment is shown in which a third hot melt butyl adhesive 50 is applied between the first adhesive 26 and the vapor barrier 30 to orient the vapor barrier 30 at both ends perpendicular to the pair of parallel glass panes 32 and 34 . The amount of the second adhesive 28 used is less than the amount used in the second embodiment of FIG. 3 . The third adhesive 50 may be uncured silicone or urethane.
Also, instead of the diagonally cut corners 46 and 48 of FIG. 3, the twelfth embodiment in FIG. 5 has smaller square cut corners 46 a and 48 a so that the desiccant 38 is left with a top surface 54 and a bottom surface 56 which provide additional frictional engagement with the top glass pane 32 and the bottom glass pane 34 , respectively. In this twelfth embodiment, the six-sided spacer 10 is the same size as the spacer 10 , shown in the first and second embodiments of FIGS. 1-3, with the top surface 54 , the bottom surface 56 , two other sides, and at least two cut corners 46 a and 48 a. In other words, the top surface 54 and the bottom surface 56 of the core spacer 10 have a pattern cut therein, as seen in FIG. 5, to form voids which receive the second adhesive 28 . This pattern may be described as a plurality of shallow channels.
When heat is applied to cure the third adhesive 50 , the entire assembly of FIG. 5 has more structural integrity because the cured third adhesive 50 attaches itself firmly to the second adhesive 26 , the metallized vapor barrier 30 , and both glass panes 32 and 34 .
In FIG. 6, the first embodiment of FIGS. 1 and 2 is shown in place, without the second adhesive 28 and the desiccant 38 , for ease of illustration. The spacer 10 is adhered at its top side 12 to the top glass pane 32 and also is adhered at its bottom side 14 to the bottom glass pane 34 . The glass panes 32 and 34 are parallel to each other but are separated by an interior space 52 to form an entire insulated glass assembly. The spacer 10 and the core 24 extend around the entire periphery and go around corners between the panes 32 and 34 in an airtight manner to form the entire insulated glass assembly. At a 90° corner 42 , either the spacer 10 is flexed, thus causing some curvature in the corner 42 , or the spacer 10 is cut, thus allowing a sharp 90° corner 42 to be formed. In the latter case, an exterior corner void is back-filled with the adhesive 26 , as shown in the embodiments of FIGS. 2, 3 and 5 . Note that it is necessary to cut only the spacer 10 and not any other materials, such as the second adhesive 28 and the desiccant 38 in FIG. 2 or the same two materials and the vapor barrier 30 in FIG. 3, or the three last listed materials and the adhesive 50 in FIG. 5 . Consequently, the nonstretchable fiberglass cord 24 running therethrough allows the rubber spacer 10 to maintain its structural integrity by preventing the rubber spacer 10 from stretching. Thus, the entire insulated glass assembly is kept intact so that no moisture enters the interior space 52 between the panes 32 and 34 .
The present invention also encompasses a method for manufacturing the insulated assembly having the interior space. The method includes an initial step of providing the pair of parallel glass panes 32 and 34 separated by the interior space. The method also includes the further steps of embedding the nonheating, nonstretchable cord 24 in a central position of the rubber core spacer so that the rubber core spacer 10 is not stretchable; applying the first adhesive 26 around at least two sides of the core spacer 10 for sticking the core spacer 10 between the pair of parallel glass panes 32 and 34 ; arranging the desiccant 38 adjacent to the core spacer 10 and spacing the desiccant 38 between the pair of parallel glass panes 32 and 34 ; applying the second adhesive 28 around at least two sides of the desiccant 38 to hold the desiccant 38 between the pair of parallel glass panes 32 and 34 ; holding the vapor barrier 30 in place between the core spacer 10 and the desiccant 38 ; and applying the third adhesive 50 between the first adhesive 26 and the vapor barrier 30 to orient the vapor barrier 30 at both ends perpendicular to the pair of parallel glass panes 32 and 34 . The last step is extending the core spacer 10 and the cord 24 around the periphery and around the corners between the pair of parallel glass panes 32 and 34 in an airtight manner to form the insulated assembly. In the completed assembly, as best shown in FIGS. 3 and 6, the cord 24 has a diameter no greater than about 10% of the width of the core spacer 10 .
The above-described embodiments are not limiting, but can be modified in various ways within the scope and spirit of the present invention. | Two parallel glass panes are separated by a core spacer made of either EPDM rubber or another solid rubber material with a nonheating, centrally positioned, nonstretchable fiberglass cord being embedded therein and extending longitudinally therethrough so that the core spacer is not stretchable. The EPDM rubber formulation is chemically compatible with hot melt butyl which is used as an adhesive between the solid rubber and the glass panes. The fiberglass cord is nonstretchable so that the core spacer does not deform or break apart when the core spacer is either initially manufactured or later placed between the pair of two glass panes. The core spacer and the cord extend around a periphery and go around corners between the panes in an airtight manner to form an insulated assembly. Also, the cord has a diameter no greater than about 10% of a width of the core spacer. A method for manufacturing the insulated assembly is likewise disclosed. | 4 |
FIELD OF THE INVENTION
[0001] The present invention is related to the biological control of plant diseases caused by Fusarium species. Specially, it relates to biocontrol compositions comprising a mixture of at least one microorganism which is an antagonist against plant pathogens and an appropriate carrier, as well as to a process for control of the plant pathogen and to increase yield. The invention includes as a plant pathogen the pathogenic fungus Gibberella zeae (anamorph Fusarium graminearum ), and as antagonist microorganisms the novel isolates of Pantoea agglomerans (Embr. 1494, Accession ATCC PTA 3460) and of Bacillus megaterium (Embr. 9790, Accession ATCC PTA 3461).
BACKGROUND OF INVENTION
[0002] Fruit, vegetables, and plants are all susceptible to attack by fungi, resulting in loss of crops, decreased shelf-life of produce, and ultimately higher costs for consumers. Many fungi are known pathogens in several diseases which harm or destroy crops worldwide. Examples of such fungi include those belonging to the genera Rhizoctonia, Pythium, Gaeumannomyces, and Fusarium.
[0003] For a number of years, it has been known that various microorganisms exhibit biological activity useful in controlling plant diseases. Although progress has been made in the field of identifying and developing biological pesticides for controlling plant diseases of agronomic and horticultural importance, most of the pesticides in use are still synthetic compounds. Many of the chemical fungicides are carcinogenic agents and, therefore, toxic to wildlife and other non-target species. In addition, pathogens may develop resistance to chemical pesticides. In fact, the fungicides, considered the major weapon in combating plant diseases, are often ineffective and pose hazards to humans and the environment. Biological control offers an attractive approach as compared with synthetic chemical fungicides. Biopesticides (living organisms and the compounds which are naturally produced by these organisms) can be safer, more biodegradable, and less expensive to develop. In addition, they are highly desired for integrated pest management programs in agriculture, public health, and urban settings.
[0004] The agricultural use of Bacillus megaterium has been reported for disease control in rice and cotton inhibition as seed treatment but not as foliar sprays. U.S. Pat. No. 5,403,583 discloses a Bacillus megaterium, ATCC 55000, and a method to control the fungal plant pathogen Rhizoctonia solani as seed treatment. Islam and Nandi also disclosed a Bacillus megaterium with antagonism to Drechslera oryzae, the causal agent of rice brown spot (Journal of Plant Diseases and Protection. 92(3): 241-246 (1985) and a Bacillus megaterium with in vitro antagonism against Drechslera oryzae, Alternaria alternata and Fusariun roseum (Journal of Plant Diseases and Protection. 92(3): 233-240 (1985). They mentioned three components in the culture filtrate. The most active antibiotic was highly soluble in water and methanol with a UV peak at 255 nm and a shoulder at 260 nm, which proved to be a polyoxin-like lipopeptide. And, Cook (Proceedings Beltwide Cotton Production-Mechanization Research Conference, Cotton Council, Memphis, p. 43-45 (1987) disclosed the use of a suspension of Bacillus megaterium to reduce the number of plants killed by Phymatotrichum omnivorum, a cause of cotton root rot. Antibiotic production of B. megaterium has also been recorded by Berdy (CRC Handbook of Antibiotic Compounds, Vols. I-XIV. CRC Press, Inc. Boca Raton. Fla. 1980-87), who reported the production of low-mammalian toxic peptide antibiotics such as ansamitocin-PDM-O, bacimethrin, megacin, pentapeptide, and homopeptides.
[0005] U.S. Pat. No. 5,494,819 describes a pure culture of Pantoea agglomerans having all of the characteristics of FERM BP-3511 which is identified by growth, morphology, physiology, utilization of carbon sources and various specific enzymatic tests involving enzymes as lysine decarboxylase, arginine dihydroxylase, phenylalanine deaminase and ornithine decarboxylase. In addition, the disclosed pure culture of Pantoea agglomerans is characterized by the required production of lipopolysaccharides to which the inventors attribute an immunity-stimulating activity. In other words, according to this document, Pantoea agglomerans is used to obtain substances to be used in pharmaceuticals.
[0006] U.S. Pat. No. 5,766,926 discloses a method comprising the steps of applying to the pulpwood or pulp substrate a bacterial inoculum of at least one of the species selected from the group consisting of Pseudomonas fluorescens, Pantoea ( Enterobacter ) agglomerans, Bacillus cereus, and Xanthomonas campestris and maintaining the substrate under conditions which allow bacterial growth for a time sufficient to effect a reduction in the resin component of the substrate by the bacteria. It is mentioned that the source of the Pantoea ( Enterobacter ) agglomerans isolate used in the method, identified by the NRRL Accession No.B21509, is Brazil.
[0007] It is known that the genus Fusarium contains species which may cause diseases of wither and blight that occur during the growth of plants and damages not only the host but also other kinds of plants. It is supposed that fusaric acid is the principal agent that brings about these diseases. Fusaric acid (5-n-butylpicolinic acid) is known to be a non-specific toxin which is produced by the metabolism of almost all plant pathogenic Fusarium fungi (Wood, R. K. et al. 1972. “Phytotoxins in plant diseases”. Academic Press. New York; Durbin, R. D. 1982. “Toxins in plant diseases”. Academic Press. New York). In the document EP 257 756, referring to the prevention of Fusarium diseases and microorganisms therefor, the inventors proposed to prevent such diseases by using microorganisms belonging to the genera Cladosporium and Pseudomonas which decompose fusaric acid. EP 441 520 relates also to detoxifying fusaric acid microorganisms, and Klebsiella oxytoca HY-1 (FERM BP-3221) is particularly mentioned.
[0008] In the document WO 92018613, it is suggested to control plant diseases caused by fungi of the genera Rhizoctonia, Pythium, and Fusarium by using a new strain of Pseudomonas fluorenscens, a seed or soil treatment but not foliar sprays.
[0009] WO 9905257, referring to biocontrol for plants with Paenibacillus macerans, Pseudomonas putida, and Sporobolomyces roseus, describes the use of isolates of these microorganisms to impart pathogen protection to plants, particularly against plant diseases caused by fungi, such as Fusarium oxysporum, Fusarium graminearum, Fusarium monilforme, Cochliobolus sativus, Collectotrichum graminicola, Stagonospora nodorum, Stagonospora avenae, Stenocarppela maydis, and Pyrenophora tritici - repentis. In this case, pathogen protection was achieved by either seed treatment or foliar sprays.
[0010] [0010] Fusarium graminearum Schw. (Teleomorph= Gibberella zeae Schw. Petch.) is the Fusarium species most frequently responsible for scab of wheat and barley in Brazil. This disease, also known as Fusarium Head Blight (FHB), is responsible for major losses which vary from 10% (see Luz, W. C. da. 1984. “Yield losses caused by fungal foliar wheat pathogens in Brazil”. Phytopathology. 74:1403-1407); to 54% (Picinini, E. C. and Fernandes, J. M. C. 1994. “Controle quimico da Gibberella zeae em trigo pelo uso de fungicidas inibidores da sintese do ergoterol”. Fitopatol. Brasileira 19 (Supl.):273). At present, available and affordable control measures, such as resistant varieties, cultural practices, and foliar fungicides, are only partially effective.
[0011] Only modest levels of resistance have been deployed in cultivars in commercial fields; the most widely grown cultivars are often most susceptible. Furthermore, the benefit of crop rotation as a control measure is reduced by the wide host range of the pathogen, especially on grasses (Costa Neto, J. P. da. 1976. “Lista de fungos sobre gramineas (capins e cereais) no Rio Grande do Sul”. Revista da Faculdade de Agronomia. UFRGS. 1:43-78; Luz, W. C. da. 1982. “Diagnose das Doencas da Cevada”. Passo Fundo—EMBRAPA-CNPT, 24p. (Circular Técnica no. 2)). Treatment with foliar fungicides remains the most important (Picinini and Fernandes, 1994) and recommended (Reunião da Comissão Sul-Brasileira de Pesquisa de Trigo, 2000) tool for reducing scab in Brazil, despite its shortcomings as a control measure. The use of certain effective fungicides has been restricted in some countries because application at late developmental stages, that is, during heading and flowering, can result in chemical residues in the harvested grain. Biological control is an additional strategy that may eventually play an important role in an integrative approach to scab management of cereals.
[0012] Screening of microorganisms to control wheat scab was initiated in Brazil in the 1980's (Luz, W. C. da. 1988. “Biocontrol of fungal pathogens of wheat with bacteria and yeasts”. Page 348 in: 5 th International Congesss of Plant Pathology, Kyoto, Japan. (Abstr.)). At the beginning, over 300 bacteria and yeasts isolated from wheat were screened in vitro against F. graminearum. This work was followed by that of Perondi et al. (Perondi, N. L., Thomas, R. and Luz, W. C. da. 1990. “Antagonistas potenciais de Fusarium graminearum ”. In: Anais do 2 ° Simpósio de Controle Biológico, Brasilia, D. F., p. 128. (Abstr.); Perondi, N. L., Thomas, R. and Luz, W. C. da. 1990. “Controle microbiano da giberela do trigo em campo”. In: Anais do II Simpósio de Controle Biológico, Brasilia, D F. P.129(Abstr.); Perondi, N. L., Luz, W. C. da. and Thomas, R. 1996. “Controle microbiológico da giberela do trigo”. Fitopatol. Brasileira 21:243-249) in which microbial strains were tested for their antagonistic action against the pathogen. Potential antagonists were selected by the funnel method (Luz, W. C. da. 1990. “Microbiological control of Bipolaris sorokiniana ‘in vitro’”. Fitopatol. Brasileira 15:246-247) which compared the effect of individual test organisms on the radial growth of F. graminearum. Promising isolates were further tested in the greenhouse and in the field for their ability to control wheat scab. Individual bioprotectants significantly diminished the severity of the disease under field conditions, raising the yield of wheat between 7 and 31% when compared to non-treated plants.
[0013] Besides the selection of the bioprotectants, it is important to overcome several difficulties related to constraints on their application to the ears of wheat and barley at flowering such as the timing of application, inoculation technology, physiological state of the organisms, spike colonization, survival of the organisms under the harsh environmental conditions, variability of biocontrol from year to year, fermentation, formulation, and storage. The partial control of any tactics to protect against FHB up to this moment indicates that the integration of protection measures would provide the best disease management.
[0014] From 1988 up to now, thousands of microorganisms have been tested for scab control. Some workers have been investigating antagonists to control FHB (Khan, N. J., Schisler, D. A., Boehm, M. J., Lipps, P. E., Slininger, P. J. and Bothast, R. J. 1998. “Biological control of scab of wheat incited by Giberella zeae ”. Pages 45-46 in: Proceedings of the 1998 National Fusarium Head Blight Forum , Michigan State University, University Printing, East Lansing. Mich.; Khan, N. J., Schisler, D. A., and Boehm, M. J. 1999. USDA-ARS, Ohio State University cooperative research on biologically controlling Fusarium Head Blight: 2. Influence of pathogen strain, inoculum spray sequence and inoculum spray time. Pages 56-59 in: Proceedings of the 1999 National Fusarium Head Blight Forum, Michigan State University, University Printing, East Lansing, Mich.; Boehm, m. J., Khan, N. J., and Schisler, D. A. 1999. USDA-ARS, Ohio State University cooperative research on biologically controlling Fusarium Head Blight: 3. Field testing of antagonists. Pages 45-48 in: Preceedings of the 1999 National Fusarium Head Blight Forum, Michigan State University, University Printing, East Lansing, Mich.; Luo, Y. and Bleakley, B. 1999. “Biological control of Fusarium Head Blight (FHB) of wheat by Bacillus strains”. Pages 78-81 in: Proceedings of the 1999 National Fusarium Head Blight Forum, Michigan State University, University Printing, East Lansing, Mich.; Schisler, D. A., Khan, N. J., and Boehm, M. J. 1999. USDA_ARS, Ohio State University cooperative research on biologically controlling Fusarium Head Blight: 1. Antagosist selection and testing on durum wheat. Pages 78-81 in: Proceedings of the 1999 National Fusarium Hrad Blight Forum, Michigan State University, University Printing, East Lansing, Mich.; Stockwell, C. A., Luz, W. C.da., and Bergstrom, G. C. 1997. “Biocontrol of wheat scab with microbial antagonists”. Phytopathology 87:S94.(Abstr.); Stockwell, C. A., Bergstrom, G. C., and Luz, W. C.da.1999. “Selection of microbial antagonists for biological control of Fusarium Head blight of wheat”. Pages 82-84. in: Proceedings of the 1999 National Fusarium Head Blight Forum, Michigan State University, University Printing, East Lansing, Mich.; Stockwell, C. A., Bergstrom, G. C., and Luz, W. C.da.2000. “Identification of bioprotectants for biological control of Gibberella zeae ” in:. Proceedings of FHB Forum), under greenhouse or field conditions. Some strains have reduced the FHB severity and significantly reduced vomitoxin contamination in grains (Stockwell et al., 1997,2000). Table 1 illustrates the chronology of researches on the biocontrol of FHB.
TABLE 1 Chronology of works done on biocontrol of Fusarium Head Blight of wheat LITERATURE BIOPROTECTANTS Lus, W.C. da, 1988 Bacteria, Yeast Perondi; N.L., Luz, W.C. da & Thomas, R, Bacillus subtilis 1990 a, 1990 b, 1996 Bacillus spp. Pseudomonas fluorescens Sporobolomyces roseus Stockwell, C.A; Luz, W.C. da, and Paenibacillus macerans Bergstrom, G.C. 1997 Pseudomonas putida Sporobolomyces roseus Khan, N.I., Scisler, D.A.. Bochm, M.J, Bacillus spp. Lipps, P.E., Slininger, P.J. and Bothast, R.J., 1998 Boehm, M.J., Khan., N.J., and Schisler, Yeast, Bacillus sp. D.A, 1999 Khan, N.J., and Schisler, D.A., and Yeast, Bacillus sp. Boehm, M.J., 1999 Luo, Y. & Bleakely, B. 1999 Bacillus spp. Schisler, D.A., Khan, N.J. and Boehm, Bacillus spp. M.J. 1999 Stockwell, C.A., Bergbstrom, G.C. and Paenibacillus macerans Luz, W.C. da. 1999 Pseudomonas putida Sporobolomyces roseus Stockwell, C.A., Bergstrom, G.C. and Paenibacillus macerans Luz, W.C. da., 2000 Bacillus spp.
SUMMARY OF THE INVENTION
[0015] According to the present invention, microbiological agents are provided for control of certain diseases of wheat and other cereals caused by Fusarium species, including Fusarium Head Blight (FHB) of wheat and other cereals. Moreover, these agents can also improve yield of said wheat plants and cereals. Specifically, these agents are novel isolates of Pantoea agglomerans and of Bacillus megaterium that exhibit the property of inhibiting fungal pathogens, particularly those produced by Fusarium species.
[0016] The first embodiment of the invention refers to a biocontrol composition comprising a mixture of at least one microorganism which is antagonist against plant pathogens and a carrier for said at least one microorganism, wherein said at least one microorganism is a bacteria selected from the group consisting of Pantoea agglomerans and Bacillus megaterium and said at least one microorganism is present in an amount effective for inhibiting plant pathogen development.
[0017] A second embodiment is related to a process for controlling the plant pathogen development on wheat and cereal plants by applying a composition containing a carrier and at least one microorganism which is an antagonist against plant pathogens selected from the group of bacteria consisting of Pantoea agglomerans and Bacillus megaterium in an amount effective to inhibit plant pathogen development on said plant.
[0018] The third embodiment is related with a process for increasing plant yield characterized by a step of applying, particularly by spraying, to the plant a composition containing a carrier and at least one microorganism selected from the group of bacteria consisting of Pantoea agglomerans and Bacillus megaterium in an amount effective to increase yield of said plants or plants resulting from treated seeds.
DETAILED DESCRIPTION OF THE INVENTION
[0019] For purposes of clarity and a complete understanding of the invention, the following terms are defined.
[0020] “Plants” is used to mean the head part of the plant to be treated.
[0021] “ Pantoea agglomerans (Embr. 1494)” means the bacterium isolate which was isolated by Embrapa and identified by the code “Embr. 1494”.
[0022] “ Bacillus megaterium (Embr. 9790)” means the bacterium isolate which was isolated by Embrapa and identified by the code “Embr. 9790”.
[0023] “CFU” refers to the abbreviation of Colony Forming Unity which is frequently used to express the concentration of microorganisms present in a composition.
[0024] Microorganisms usable in the present invention were identified by the following procedure: (i) screening plants or agricultural commodities (e.g. the surface(s) of said plant or agricultural commodity) for the presence of useful microorganisms; (ii) recovering (e.g. by washing or rising from the plant or agricultural commodity) and isolating said microorganism(s); and (iii) testing said microorganism(s) for antagonistic activity against plant pathogens. However, it should be understood that said microorganism(s) may be obtained from sources other than said plants or agricultural commodities.
[0025] The isolates of the present invention, Accession No. ATCC PTA 3460 (Embr. 1494) and Accession No. ATCC PTA 3461 (Embr. 9790), were obtained from wheat or corn plant parts, such as healthy leaves, seeds or roots by repeatedly washing the plant parts with water. The organisms were thereafter plated and grown on any nutritionally rich medium sufficient to support growth of the organisms. Preferably, the medium is nutrient agar. ATCC PTA 3460 was identified as a novel isolate of Pantoea agglomerans (Embr. 1494) and ATCC PTA 3461 was identified as a novel isolate of Bacillus megaterium (Embr. 9790).
[0026] Isolate ATCC PTA 3461 (Embr. 9790) of B. megaterium has the following characteristics: it is a Gram-positive rod, spore-forming bacteria, and the bacterial identification was accomplished based on 16S rRNA gene sequence similarity (made by Microbe Inotech Laboratories, Inc on Apr. 21, 2000 by using PE Applied Biosystem's MicroSeq™ microbial identification software and database) demonstrating that the isolate is novel and belongs to the species Bacillus megaterium (details about this characterization method may be found in Stackebrandt, E. and Goebel, B. M. 1994. “Taxonomic Note: A Place for DNA-DNA Reassociation”; and 16S rRNA Sequence Analysis in the Present Species Definition in Bacteriology. Int. J. Syst. Bacteriol. 44:846-849).
[0027] Isolate ATCC PTA 3460 (Embr. 1494) of P. agglomerans has the following characteristics: it is a Gram-negative bacteria; and, based on fat acid analysis (CG FAME method), has a similarity coefficient of 0.648 and distance coefficient of 3.310 (a good match is one with a similarity coefficient greater than 0.5 and a distance coefficient of less than 7) made by the same laboratory.
[0028] Growth of isolates ATCC PTA 3460 (Embr. 1494) and ATCC PTA 3461 (Embr. 9790) may be effected under aerobic condition at any temperature satisfactory for growth of the microorganisms, i.e., from about 10° C. to about 30° C. The preferred temperature range is 20° C. to 25° C. The pH of the nutrient medium is about neutral, i.e., 6.6 to 7.3. The incubation time is that time necessary for the isolates to reach a stationary phase of growth, preferably between 40 and 60 hours. Growth of isolates ATCC PTA 3461 (Embr. 9790) ( B. megaterium ) and ATCC PTA 3460 ( P. agglomerans ) (Embr. 1494) is preferably achieved at a temperature range of 21° C. to 23° C., with an incubation time of 45 to 50 hours, such that the cells are in the logarithmic phase of growth.
[0029] Isolates ATCC PTA 3461 (Embr. 9790) ( B. megaterium ) and ATCC PTA 3460 (Embr. 1494) ( P. agglomerans ) may be grown in any conventional test tube or shake flask for small fermentation runs. For large scale operations, the culture may be carried out in a suitable fermentation tank, under appropriate conditions provided by agitating and aerating the inoculated liquid medium. Following incubation, the isolates are harvested by conventional sedimentary methods (e.g. centrifugation) or filtering. Cultures are stored on nutrient agar at 4° C., but also at much lower temperature such as −170° C.
[0030] The bacteria of the present invention are useful to control plant pathogens by using, for example, air spraying.
[0031] The microorganisms of the present invention may be applied to wheat plants or other cereals in combination with various liquid and/or solid carriers and additives, including combination with fungicides.
[0032] In the liquid form, e.g. solutions or suspensions, the microorganisms may be mixed or suspended in water or in aqueous solutions. Suitable liquid diluents or carriers include water, aqueous solutions, petroleum distillates, or other liquid carriers.
[0033] Solid compositions can be prepared by dispersing the antagonist microorganisms in and on an appropriately divided solid carrier, such as peat, wheat, bran, vermiculite, clay, talc, bentonite, diatomaceous earth, fuller's earth, pasteurized soil, and the like. When such formulations are used as wettable powders, biologically compatible dispersing agents such as non-ionic, anionic, amphoteric, or cationic dispersing and emulsifying agents can be used.
[0034] In a preferred embodiment, the compositions contemplated herein prevent attack by Fusarium diseases upon plants, particularly cereal plants, such as wheat, barley, and corn and, when used in sufficient amounts, to act as fungi antagonist. They have a high margin of safety because they do not burn or injury the plant.
[0035] The compositions of the invention are so chemically inert that they are compatible with substantially any other constituents of the spray schedule. They may also be used in combination with biologically compatible pesticidal active agents as for example, herbicides, nematocides, fungicides, insecticides, and the like. They can also be used in combination with plant growth affecting substances, such as fertilizers, plant growth regulators, and the like, provided that such compounds or substances are biologically compatible.
[0036] The active constituents are used in a concentration sufficient to inhibit plant pathogen development of the targeted plant pathogen when applied to the cereal plant. As will be apparent to a skilled in the art, effective concentrations may vary depending upon such factors as: (a) the type of the plant or agricultural commodity; (b) the physiological condition of the plant or agricultural commodity; (c) the concentration of pathogens affecting the plant or agricultural commodity; (d) the type of disease injury on the plant or agricultural commodity; (e) weather conditions (e.g. temperature, humidity); and (f) the stage of plant disease. According to the invention, typical concentrations are those higher than 1×10 2 CFU/ml of carrier. Preferred concentrations range from about 1×10 4 to about 1×10 9 CFU/ml, such as the concentrations ranging from 1×10 6 to 1×10 8 CFU/ml. More preferred concentrations are those of from about 37.5 to about 150 mg/g of dry bacterial mass per of carrier (dry formulation) or per ml of carrier (liquid composition).
[0037] The compositions of the invention may be applied to the wheat plant or other cereals using conventional methods such as dusting, injecting, rubbing, rolling, dipping, spraying, or brushing, or any other appropriate technique which does not injury the wheat plant or other cereals to be treated. Particularly preferred is the spray method.
[0038] The following specific examples are presented to more particularly illustrate the invention and should not be construed as a limitation thereon.
EXAMPLE 1
[0039] Effect of Bioprotectant Microorganisms of the Present Invention on Radial Growth of Gibberella zeae in Vitro.
[0040] In paired treatments, the radial growth (cm) of Gibberella zeae, in the presence of the isolate ATCC PTA 3461., corresponding to Bacillus megaterium (Embr. 9790) and the isolate ATCC PTA 3460, corresponding to Pantoea agglomerans (Embr. 1494), was reduced substantially.
[0041] The antagonist activity of the isolated microorganisms was determined by using the Antibiosis method as described in Luz (1990). Thousands of microorganisms were tested against Gibberella zeae. Each isolate was transferred onto Petri dishes containing nutrient agar in a circular pattern by means of a small sterile glass funnel. After 48 hours of incubation at 22° C. to 25° C., an agar disk containing a G. zeae colony was transferred into the center of the ring-shaped colony of the bioagent or, in the control treatment, onto an uninoculated media plate. The plates were incubated under fluorescent lights at 22° C. and under a photoperiod of 12 hours, in a completely randomized design. The radial growth of the pathogen was measured after three to five days, and the result was 2.5 to 3.0 cm. Further measurements were made to permit the assessment of the experiment. The data were calculated as % inhibition.
[0042] The data were subjected to analysis of variance and the means calculated by the Fisher test.
[0043] The pathogen growth reduction varied from 74% to 79% for B. megaterium and 25% to 38% for P. agglomerans . The results are shown in Table 2. In this table, the means within a column are significantly different (at p=0.05) from each other if they are followed by different letters, according to Fisher's least significant difference test.
TABLE 2 Effect of bioprotectants on radial growth of Gibberella zeae RADIAL % RE- GROWTH DUCTION TREATMENTS run 1 run 2 run 1 run 2 Nontreated 2.00 c 3.5 c — — ATCC PTA 3461 0.42 a 0.9 a 79 74 ( Bacillus megaterium -Embr. 9790) ATCC PTA 3460 1.23 b 2.6 b 38 25 ( Pantoea agglomerans -Embr. 1494)
EXAMPLE 2
[0044] Biocontrol of Wheat Scab (Fusarium Head Blight) Under Growth Chamber Conditions.
[0045] Cultivar and growth conditions—A susceptible wheat variety to be infected by Fusarium was produced in EMBRAPA-Centro Nacional de Pesquisa de Trigo (CNPT), Brazil. This cultivar was planted under growth chamber providing adequate environmental conditions. Healthy-like plants (without disease symptoms) were grown and transferred to suitable pots and maintained in 12 hours-period dark at 20 ° C.
[0046] Pathogen preservation and inoculum production—A pure culture of G. zeae isolate, obtained by EMBRAPA-Centro Nacional de Pesquisa de Trigo (CNPT), Brazil, onto a BDA containing streptomycin medium was stored at 4° C. to avoid previous bacteria growth. F. graminearum inoculum was obtained from conidia which have been inoculated onto a BDA medium. Sporogenesis was observed after 3-5 days from the inoculation.
[0047] Antagonists treatment—The isolates were assessed under growth chamber conditions at the stage of initial flowering. Ears were uniformly sprayed with a suspension containing each isolate. The ears were treated with suspensions containing only one isolate and in a concentration of approximately 10 7 CFU/ml. There were nine replicates per treatment and one blank (water without microorganisms).
[0048] Pathogen Inoculation and disease assessment—The pathogen was inoculated 24 hours after antagonists treatment by spraying the ears with an aqueous suspension containing 10 4 conidia of G. zeae /ml. The inoculated plants were stored in a humid chamber for 48 hours. The disease assessment was made 15 days after pathogen inoculation. Disease severity was assessed by calculating the percentage of the scabby spikelets.
[0049] Biocontrol agents namely, Isolate ATCC PTA 3461 ( Bacillus megaterium (Embr. 9790)) and Isolate ATCC PTA 3460 ( Pantoea agglomerans (Embr. 1494)) significantly reduced the percentage of scabby spikelets when tested in growth chambers either using fresh bacterial cells or fermented and dry preparations. The results are shown in Table 3. In this table, the means within a column are significantly different (at p=0.05) from each other if they are followed by different letters.
TABLE 3 Biochemical of wheat scab ( Fusarium head blight) as measured by decrease in disease severity under growth chamber conditions. DISEASE SEVERITY (%) TREATMENTS run 1 run 2 run 3 run 4 Nontreated 54 b 86 b 62 c 68 b ATCC PTA 3461 18 a 12 a 15 a 14 a ( Bacillus megaterium (Embr. 9790) (fresh cell)) ATCC PTA 3460 21 a 10 a 12 a 12 a ( Pantoea agglomerans (Embr. 1494) (fresh cell) ATCC PTA 3461 ( Bacillus megaterium — — 20 b 24 b (Embr. 9790)) (wettable powder) ATCC PTA 3460 ( Pantoea agglomerans — — 22 b 18 b (Embr. 1494)) (wettable powder)
EXAMPLE 3
[0050] Biocontrol of Scab of Wheat Under Field Conditions.
[0051] Field experiment, plant treatment with the antagonists of the invention—The experiment was carried out in an agricultural Brazilian area which is used for scab of wheat microbiological control, where natural disease infection occurs. The wheat variety used in the test was a Fusarium graminearum susceptible variety. Wheat plants with each treatment (concentration of 10 7 CFU) were sown in plots of 12 rows, 3 m long. The space between rows was 20 cm. Treated plots in each experiment were arranged in a randomized block design.
[0052] Wettable powder compositions containing, individually, isolate ATCC PTA 3461 ( B. megaterium ) and isolate ATCC PTA 3460 ( Pantoea aglomerans ) of the present invention were also assessed.
[0053] Disease Severity and Yield Assessment—After 15 days from the application of the antagonists of the invention to wheat plants, the natural disease severity was assessed. Yield was also calculated in kg/ha.
[0054] As shown in Table 4, Isolate ATCC PTA 3461 ( Bacillus megaterium (Embr. 9790)) and Isolate ATCC PTA 3460 ( Pantoea agglomerans (Embr. 1494)) significantly diminished the disease incidence up to 50% and severity up to 67% in the field and the yield increase varied from 809 to 861 kg/ha (Table 4).
[0055] These results show that the biological control measure using these two bioagents play an important role in the management of scab on wheat.
TABLE 4 Biocontrol of wheat scab ( Fusarium Head Blight) as measured by decrease in incidence and severity of the disease, and yield impact under field conditions DISEASE YIELD TREATMENTS Incidence Severity (kg/ha) Nontreated 60 b 30 b 3328 b ATCC PTA 3461 ( Bacillus megaterium - 30 a 10 a 4189 a Embr. 9790) ATCC PTA 3460 ( Pantoea agglomer- 29 a 11 a 4137 a ans Embr. 1494) | Microbiological agents are provided for control of certain diseases of wheat and other cereals caused by Fusarium species, including Fusarium head blight of wheat and other cereals. These agents can also improve yield of wheat plants and cereals. The agents are novel isolates of Pantoea agglomerans and of Bacillus megaterium that exhibit the property of inhibiting fungal pathogens, particularly those produced by Fusarium species.
Biocontrol compositions, and methods of using them to control plant pathogen development on wheat and cereal plants and for increasing plant yield, are also provided. The biocontrol compositions comprise a mixture of at least one microorganism selected from the group consisting of Pantoea agglomerans and Bacillus megaterium. | 0 |
BACKGROUND
This specification relates to optical communications.
Conventional optical circulators are employed in systems transmitting optical signals in order to transmit optical signals in a particular direction. For example, in a three port optical circulator, an optical signal input at the first port will be transmitted to the second port. An optical signal input at the second port will be transmitted to the third port. However, optical signals typically will not be transmitted in the reverse direction. For example, an optical signal input at the second port will not be transmitted to the first port.
SUMMARY
In general, one innovative aspect of the subject matter described in this specification can be embodied in optical circulator arrays that include a plurality of stacked three port circulators each having a respective first port of a first port array, a respective second port of a second port array, and a respective third port of a third port array, wherein each of the plurality of stacked three port circulators share optical components including: a first Wollaston prism coupled to the first port array, a first lens, a first half wave plate, a polarization dependent beam path separator, a second half wave plate, a second lens, a propagation direction dependent polarization rotation assembly, a second Wollaston prism coupled to the second port array, and a third Wollaston prism coupled to the third port array.
The foregoing and other embodiments can each optionally include one or more of the following features, alone or in combination. In particular, one embodiment includes all the following features in combination. The propagation direction dependent polarization rotation assembly includes a Faraday rotator and a half wave plate. Each port array includes one or more thermal expansion core (TEC) fibers. The polarization dependent beam path separator includes a birefringence wedge pair. The birefringence wedge pair includes: a first wedge optically coupled to a first side of the birefringence wedge pair; and a second wedge optically coupled to a second side of the birefringence wedge pair, wherein the first wedge and the second wedge correct parallelization of light beams passing through the optical circulator array. The polarization dependent beam path separator includes an optical beam separator with polarization dependent coating. The TEC fibers, first lens, second lens, and polarization dependent beam path separator are positioned in a double telemetric configuration layout. The polarization dependent beam path separator provides beam path routing from the first port to the second port and from the second port to the third port based on a polarization orientation of incident light beams. The polarization dependent beam path separator is optically coupled between the first lens and the second lens. The propagation direction dependent polarization rotation assembly is optically coupled between the second Wollaston prism and the second lens.
The optical circulator array further includes a second propagation direction dependent polarization rotation assembly coupled to the first port; and a third propagation direction dependent polarization rotation assembly coupled to the third port, wherein the second propagation direction dependent polarization rotation assembly is optically coupled between the first Wollaston prism and the first lens, and the third propagation direction dependent polarization rotation assembly is optically coupled between the third Wollaston prism and the first lens. The second propagation direction dependent polarization rotation assembly provides isolation to reduce light leakage along a path from the second port to the first port.
The third propagation direction dependent polarization rotation assembly provides isolation to reduce light leakage along a path from the third port to the second port. Light beams input at the first port are randomly polarized and wherein the first Wollaston prism and the first half wave plate provide polarization conditioning.
In general, one innovative aspect of the subject matter described in this specification can be embodied in optical circulator arrays that include a plurality of stacked three port circulators each having a respective first port of a first port array, a respective second port of a second port array, and a respective third port of a third port array, wherein each of the plurality of stacked three port circulators share optical components including: a first micro lens array optically coupled to the first port array and the third port array, a first walk off crystal, a first half wave plate, a first faraday rotator, a first birefringence wedge pair, a second birefringence wedge pair, a second Faraday rotator, a second half wave plate, a second birefringence walk off crystal, and a second micro lens array optically coupled to the second port array.
Particular embodiments of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages. An optical circulator array allows multiple three port circulators to be stacked so that they each use a common set of optical components. The array of circulators can be aligned substantially concurrently.
The details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a diagram of an example optical circulator array on a port beams routing Y-Z plane.
FIG. 1B is a diagram of an example single optical circulator of the optical circulator array of FIG. 1A on a polarization conditioning X-Z plane.
FIG. 1C is a diagram of the example optical circulator array of FIG. 1A on an array stacking and polarization conditioning X-Z plane.
FIG. 2A is a diagram of an example optical circulator array on a port beams routing Y-Z plane.
FIG. 2B is a diagram of an example single optical circulator of the optical circulator array of FIG. 2A on a polarization conditioning X-Z plane.
FIG. 2C is a diagram of the example optical circulator array of FIG. 2A on an array stacking and polarization conditioning X-Z plane.
FIG. 3A is a diagram of an example circulator array on a port beam routing and polarization conditioning Y-Z plane.
FIG. 3B is a diagram of the example circulator array of FIG. 3A on an array stacking X-Z plane.
Like reference numbers and designations in the various drawings indicate like elements.
DETAILED DESCRIPTION
FIGS. 1A-C illustrate an example optical circulator array 100 . FIG. 1A is a diagram of the example optical circulator array 100 on a port beams routing Y-Z plane. FIG. 1B is a diagram of an example single optical circulator of the optical circulator array 100 of FIG. 1A on a polarization conditioning X-Z plane. FIG. 1C is a diagram of the example optical circulator array 100 of FIG. 1A on an array stacking and polarization conditioning X-Z plane showing light paths for multiple circulators of the optical circulator array 100 .
The optical circulator array 100 includes a first port array 101 , a second port array 113 , and a third port array 117 . The optical circulator array 100 is configured such that an input beam from an optical fiber at the first port array 101 is routed to an output optical fiber at the second port array 113 and that an input beam from an optical fiber at the second port array 113 is routed to an output fiber at the third port array 117 . The optical circulator array 100 provides an array of multiple three port optical circulators stacked on the X-Z plane. Each optical circulator of the array shares the optical ports and optical components. The optical circulators of the array can be aligned at the same time.
FIG. 1A shows beam paths for an optical input from the first port array 101 to output at the second port array 113 and an optical input from the second port array 113 to output at the third port array 117 .
Each of the first port array 101 , second port array 113 and third port array 117 can include or be coupled to one or more thermal expansion core (TEC) fiber that allows multiple optical signals to be input and output from the respective port arrays of the optical circulator array 100 . A TEC fiber has an enlarged mode field diameter obtained through heating relative to a typical single mode optical fiber.
With reference to FIG. 1A , a light beam input at the first port array 101 through a corresponding TEC fiber has a random polarization. The input beam passes through a first Wollaston prism 102 . The first Wollaston prism 102 includes a pair of wedge prisms. The optic axes of the wedge prisms are perpendicular to each other such that the light beam exiting the Wollaston prism 102 diverges based on polarization direction such that two orthogonally polarized light beams result. After the TEC fiber the Gaussian beam divergence angle is reduced that allows two orthogonally polarized light beams to be clearly separated angularly by Wollaston prism 102 . A C-axis of the first wedge prism of the Wollaston prism 102 is parallel to the X-Z plane and the C-axis of the second wedge prism of the Wollaston prism 102 is perpendicular to the X-Z plane.
The light beams exiting the Wollaston prism 102 then pass through a first propagation direction dependent polarization rotation assembly. The first propagation direction dependent polarization rotation assembly includes a first 45 degree Faraday rotator 103 and a first 22.5 degree cut half wave plate 104 . In the propagation direction from the first port array 101 to the second port array 113 , the first propagation direction dependent polarization rotation assembly provides zero degrees of polarization rotation. The light beams then pass through a first lens 105 , which collimates the light beams so that they are substantially parallel.
As shown in FIG. 1B illustrating beam paths for a single optical circulator along the X-Z plane, one of the two orthogonally polarized light beams that is polarized parallel to the X-Z plane passes through a 45 degree cut half wave plate 106 such that its polarization is rotated by 90 degrees to the direction that is perpendicular to the X-Z plane. The light beam exiting the 45 degree cut half wave plate 106 is directed to a Y-Z plane birefringence wedge pair or Wollaston prism 107 .
The other orthogonally polarized light beam is polarized perpendicular to the X-Z plane is directly passed to the Y-Z plane birefringence wedge pair 107 , which may be another Wollaston prism. Consequently, the two light beams have the same polarization direction upon entering the Y-Z plane birefringence wedge pair or Wollaston prism 107 .
The Y-Z plane birefringence wedge pair or Wollaston prism 107 is configured such that it passes the light beams having the same polarization direction that is perpendicular to the X-Z plane from a beam path corresponding to the first port array 101 to a beam path toward the second port array 113 . The light beam that corresponds to the bream that passed directly from the first lens 105 to the Y-Z plane birefringence wedge pair or Wollaston prism 107 is then passed through a 45 degree cut half wave plate 108 resulting in a polarization rotation of 90 degrees to the direction that is parallel to the X-Z plane. The light beam exiting the 45 degree cut half wave plate 108 is directed to a second lens 109 .
The other light beam, which passed through the 45 degree cut half wave plate 106 , is directly coupled to the second lens 109 without passing through the 45 degree cut half wave plate 108 . Therefore, the light beam remains polarized in the direction perpendicular to the X-Z plane as it is coupled to the second lens 109 .
The Y-Z plane birefringence wedge pair 107 includes two crystal wedges having orthogonal axes to each other. The C-axis of the first wedge of the Y-Z plane birefringence wedge pair 107 is perpendicular to the Y-Z plane and the C-axis of the second wedge of the Y-Z plane birefringence wedge pair 107 is parallel to the Y-Z plane.
After the light beams pass through the second lens 109 , the light beams are coupled to a second propagation direction dependent polarization rotation assembly. The second propagation direction dependent polarization rotation assembly includes a second 45 degree Faraday rotator 111 and a second 22.5 degree cut half wave plate 110 . In the propagation direction from the first port array 101 to the second port array 113 , the second propagation direction dependent polarization rotation assembly provides zero degrees of polarization rotation.
After passing through the second propagation direction dependent polarization rotation assembly, the light beams are coupled to a second Wollaston prism 112 . The second Wollaston prism 112 includes a pair of wedge prisms. The C-axis of the first wedge of the second Wollaston prism 112 is parallel to X-Z plane and the C-axis of the second wedge of the second Wollaston prism 112 is perpendicular to X-Z plane. Upon exiting the second Wollaston prism 112 , the light beams are recombined into a single light beam, which is focused into a TEC fiber of the second output port array 113 .
A light beam input at the second port array 113 follows an optical path through the optical circulator array 100 to be output by an optical fiber at the third port array 117 . A light beam input at the second port array 113 passes through the second Wollaston prism 112 , which causes the light beam to diverge into two orthogonally polarized light beams. After the TEC fiber the Gaussian beam divergence angle is reduced, which allows two orthogonally polarized light beams to be clearly separated angularly by Wollaston prism 112 . The light beams pass through the second propagation direction dependent polarization rotation assembly in the opposite direction to the propagation path from the first port array 101 to the second port array 113 . As a result, the second 45 degree Faraday rotator 111 and a second 22.5 degree cut half wave plate 110 provide a 90 degree polarization rotation in combination. However, both light beams remain orthogonally polarized with respect to each other.
Upon passing through the lens 109 a first orthogonal beam polarized parallel to the X-Z plane passes directly to the birefringence wedge pair 107 while the second orthogonal beam passes through the 45 degree cut half wave plate 108 resulting in a polarization rotation of 90 degrees before passing through the birefringence wedge pair 107 . Thus, upon entering the birefringence wedge pair 107 , both light beams have the same polarization direction, which is parallel to the X-Z plane. As a result, the birefringence wedge pair or port beam routing Wollaston Prism 107 directs the light beams along a beam path toward the third port array 117 .
The lens 105 focuses the light beams to a third propagation direction dependent polarization rotation assembly. The third propagation direction dependent polarization rotation assembly includes a third 22.5 degree cut half wave plate 114 and a third 45 degree Faraday rotator 115 . In the propagation direction from the second port array 113 to the third port array 117 , the third 22.5 degree cut half wave plate 114 and the third 45 degree Faraday rotator 115 provide a 90 degree polarization rotation in combination to each respective light beam.
The light beams exiting the third propagation direction dependent polarization rotation assembly then enter a third Wollaston prism 116 . Upon exiting the third Wollaston prism 116 , the light beams are recombined into a single light beam, which is focused into a particular TEC fiber of the third output port array 117 .
Thus, the light beams are routed onto the path to the third port array 117 after the Y-Z birefringence wedge pair 107 . The arrangements of polarization rotation components including half wave plate 108 , half wave plate 106 , half wave plate 114 and half wave plate 115 are configured that two beam components separated by the second Wollaston prism 112 when input from the second port array 113 can be recombined in the third Wollaston prism 116 .
Leakage of light in a reverse path of the circulator array 100 from the second port array 113 to the first port array 101 can be further isolated by the combination of the first 45 degree Faraday rotator 103 and the first 22.5 degree cut half wave plate 104 . In the light propagation direction of from the second port array 113 to the first port array 101 , the combination of the first 45 degree Faraday rotator 103 and the first 22.5 degree cut half wave plate 104 will provide 90 degree polarization rotation such that the leakage light, which has a polarization perpendicular to X-Z plane, cannot be recombined by the first Wollaston prism 102 and thereby cannot be directed to an optical fiber of the first port array 101 . Light leakage from the third port array 117 to the second port array 113 can be similarly isolated.
FIG. 1C illustrates an array of three port optical circulators on the X-Z plane. In particular, the components described above, particularly the layout of the input TEC fibers, first lens 105 , birefringence wedge pair 107 , second lens 109 , and output TEC fibers are arranged in a double telemetric configuration layout.
In a double telemetric configuration layout, the one or more TEC fibers of the first port array 101 and the third port array 117 are located at a rear focal plane of the first lens 105 . The birefringence wedge pair 107 for port beam path routing is located at the front focal plane of the first lens 105 and at the rear focal plane of the second lens 109 . Similarly, the one or more TEC fibers of the second port array 113 are located at a front focal plane of the second lens 109 .
Because of the optical features provided by the double telemetric configuration: the input beams from the TEC fibers at the first port array 101 TEC fibers can be collimated by the first lens 105 ; the light beams crossing at the birefringence wedge pair 107 can also be refocused by the second lens 109 to the TEC fibers of the second port array 113 with a same incident angle; and the light beams input from a top TEC fiber of the first port array 101 is imaged onto a bottom output TEC fiber of the second port array 113 . Similarly, the input beams from the TEC fibers of the second port array 113 can be collimated by the second lens 109 ; the light beams crossing at the birefringence wedge pair 107 can also be refocused by the first lens 105 onto the TEC fibers of the third port array 117 with a same incident angle; and the light beams input from a top TEC fiber of the second port array 113 is imaged onto a bottom output TEC fiber of the third port array 117 . For each of the output ports, all the receiving TEC fibers are at the same focusing plane of the lens and the incoming light beams are of the same incidence angle, so all the circulators in the array can be aligned simultaneously.
FIGS. 2A-C illustrate an example optical circulator array 200 FIG. 2A is a diagram of the example optical circulator array 200 on a port beam routing Y-Z plane. FIG. 2B is a diagram of an example single optical circulator of the optical circulator array 200 of FIG. 2A on a polarization conditioning X-Z plane. FIG. 2C is a diagram of the example optical circulator array 200 of FIG. 2A on an array stacking and polarization conditioning X-Z plane which illustrates light paths for multiple circulators of the optical circulator array 200 .
The optical circulator array 200 includes a first port array 201 , a second port array 213 , and a third port array 217 . The optical circulator array 200 is configured such that an input beam from an optical fiber at the first port array 201 is routed to an output optical fiber at the second port array 213 and that an input beam from an optical fiber at the second port array 213 is routed to an output optical fiber at the third port array 217 . The optical circulator array 200 provides an array of multiple three port optical circulators stacked on the X-Z plane. Each optical circulator of the array shares the optical ports and optical components. The optical circulators of the array can be aligned at the same time.
The optical circulator array 200 has a similar structure to the optical circulator array 100 of FIGS. 1A-C . In particular, the optical circulator array 200 includes optical components in a similar configuration including one or more TEC fibers at each port array, and from a propagation direction from the first input port array 201 , a first Wollaston prism 202 , a first propagation direction dependent polarization rotation assembly that includes a first 45 degree Faraday rotator 203 and a first 22.5 degree cut half wave plate 204 , a first lens 205 , a 45 degree cut half wave plate 206 , a birefringence wedge pair 207 , a 45 degree cut half wave plate 208 , a second lens 209 , a second propagation direction dependent polarization rotation assembly that includes a second 45 degree Faraday rotator 211 and a second 22.5 degree cut half wave plate 210 , and a second Wollaston prism 212 . Light exiting the second Wollaston prism 212 passes through the second port array 213 .
In the direction of propagation of light beams from the second port array 113 to the third port array 117 , following the first lens 205 , the circulator array 200 includes a third propagation direction dependent polarization rotation assembly and a third Wollaston prism 216 . The third propagation direction dependent polarization rotation assembly includes a third 22.5 degree cut half wave plate 214 and a third 45 degree Faraday rotator 215 . Light exiting the third Wollaston prism 216 passes through the third port array 217 .
Light beams input at the first port array 202 follow beam paths to the second port array 213 through the above components in a similar manner as described above with respect to FIGS. 1 A-C. Similarly, light beams input at the second port array 213 follow beam paths to the third port array 217 in a similar manner as described above with respect to FIG. 1 A-C.
The optical circulator array 200 differs from the structure of the optical circulator array 100 in the addition of optical X-Z plane wedge components 218 and 219 . The optical X-Z plane wedge component 218 is positioned on a first side of the birefringence wedge pair 207 facing the first lens 205 . The optical X-Z plane wedge component 219 is positioned on a second side of the birefringence wedge pair 207 facing the second lens 209 . The purpose of adding the optical X-Z plane wedge components 218 and 219 is to correct beam parallelisms. In particular, because of the physical size and arrangement of the components in the circulator array 200 , the polarization beam separation optics, e.g., first Wollaston prism 202 , second Wollaston prism 212 , and third Wollaston prism 216 , cannot be exactly located at the focal planes of the first lens 205 or the second lens 209 . On the X-Z plane as shown in FIGS. 2B and 2C , the separated polarized beams cannot be collimated to two exactly parallel beams after the collimating lenses 205 / 209 without the additional correction provided by the wedge components 218 and 219 .
FIG. 3A is a diagram of an example circulator array 300 on a port beam routing Y-Z plane. FIG. 3B is a diagram of the example circulator array 300 of FIG. 3A on an array stacking X-Z plane.
The optical circulator array 300 includes a first and third port array and a second port array. In particular, the first and third port array includes TEC fibers and a micro-lens array 301 . The second port array includes TEC fibers and a micro lens array 310 . The optical circulator array 300 is configured such that an input beam from an optical fiber at the first port array is routed to an output optical fiber at the second port array and that an input beam from an optical fiber at the second port array is routed to an output optical fiber at the third port array.
Referring to FIG. 3A , a light beam input at the first port of the first and third port array through a corresponding TEC fiber has a random polarization. The input beam is collimated by a lens of the micro lens array 301 and directed through a first Y-Z plane walk-off crystal 302 . The first walk-off crystal 302 separates the incoming light beam into two beams having orthogonal polarizations. One of the two orthogonally polarized light beams, which is initially polarized parallel to X-Z plane will pass through a first 45 degree cut half wave plate 303 and its polarization will be rotated by 90 degrees to the direction that is perpendicular to X-Z plane. The light beam will then pass through a propagation direction dependent polarization rotator component, a first Faraday rotator 304 . For light beams propagating in the direction from the first port array to the second port array, the propagation direction dependent polarization rotation assembly 304 provides 45 degree polarization rotation.
The other polarized light component, which is initially polarized perpendicular to X-Z plane, will be directly passed to the first Faraday rotator 304 .
After the first Faraday rotator 304 , the polarization direction of both light beams will be rotated by 45 degrees. However, due to the rotation by the first half wave plate 303 of one of the light beams, both light beams will share the same polarization orientation when they reach a first Y-Z plane birefringence wedge pair 305 , which may be a Wollaston prism.
The first birefringence wedge pair 305 includes two crystal wedges having orthogonal crystal axes to each other. A C-axis of a first wedge of the birefringence wedge pair 305 is at a 45 degree angle with respect to the X-Z plane and the Y-Z plane. The C-axis of a second wedge of the first birefringence wedge pair 305 is at a −45 degree angle with respect to X-Z plane and Y-Z plane. The first birefringence wedge pair 305 is used to separate the beam paths for from the first port to the second port array 310 and from the second port array 310 to the third port.
Additionally, a second birefringence wedge pair 306 positioned following the first birefringence wedge pair 305 in the propagation direction from the first port to the second port array 310 . The second birefringence wedge pair 306 is used to correct the parallelism of the beam paths.
Upon exiting the first birefringence wedge pair 305 and the second birefringence wedge pair 306 , the two light beams are parallel to the Z-axis and are passed to a second Faraday rotator 307 .
The second Faraday rotator 307 rotates the polarization of both light beams by 45 degrees such that the polarization direction of both light beams is parallel to the Y-Z plane. The light beam that was sent to the first birefringence wedge pair 305 from the first port without passing through the first half wave plate 303 passes through a second 45 degree cut half wave plate 308 and its polarization will rotated by 90 degrees to the direction that perpendicular to Y-Z plane. The two light beams then pass through a second walk-off crystal 309 where they are combined into a single light beam that is coupled to a lens 310 which focuses the light beam on an output TEC fiber of the second port array.
In the propagation direction from the second port array to the third port array, a light beam is input from a TEC fiber of the second port array and is collimated by a lens of micro lens array 310 . The light beam is then separated into two orthogonally polarized beams by the second walk-off crystal 309 . The light beam that is perpendicular to Y-Z plane is rotated 90 degrees by the second 45 degree cut half wave plate 308 and is sent to the second Faraday rotator 307 . The light beam with a polarization direction that is parallel to Y-Z plane is sent directly to the second Faraday rotator 307 .
The Faraday rotator is non-reciprocal and following the second Faraday rotator 307 the two light beams will have a polarization direction that is orthogonal to the polarization direction of the light beam at this point of the optical circulator array 300 in the opposite propagation direction from the first port array to the second port array. As a result, the first and second birefringence wedge pairs 305 and 306 will direct the light beams along a beam path toward the third port array. The two light beams are then directed through the first Faraday rotator 304 and their polarization direction are rotated 45 degrees. A first light beam is rotated by 90 degrees by the first 45 degree cut half wave plate 303 and is then combined with the other light beam in the first walk-off crystal 302 . The combined light beam exiting the first walk-off crystal 302 is focused by a lens of the micro lens array 301 to a particular TEC fiber at the third port array.
FIG. 3B shows an array of three port optical circulators stacked on the X-Z plane. The first port and the third port are a dual row configuration on the Y-Z plane. The first dual row TEC fiber array is located at the front of a first dual row lens array 301 . The second port is a single row configuration on Y-Z plane and the second single row TEC fiber array is located at a rear of the second single row lens array 310 . The different optical circulator arrays each share the same polarization rotation assembly described above.
In particular, as shown in FIG. 3A , all optical pasts are in the Y-Z plane for each three port circulator. As shown in FIG. 3B , each of the light beams from the first port array of TEC fibers are guided to the TEC fibers of the second port array and the light beams from the second port array of TEC fibers will be guided to the TEC fibers of the third port array. The plane includes an optical path from a first port to a second port and an optical path from the second port to a third port for a given three port circulator. Each plane is parallel to other optical path planes of other three port circulator of the array.
While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.
Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. | Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for optical communications. In one aspect, an optical circulator array includes a plurality of stacked three port circulators each having a respective first port of a first port array, a respective second port of a second port array, and a respective third port of a third port array, wherein each of the plurality of stacked three port circulators share optical components including: a first Wollaston prism coupled to the first port array, a first lens, a first half wave plate, a polarization dependent beam path separator, a second half wave plate, a second lens, a propagation direction dependent polarization rotation assembly, a second Wollaston prism coupled to the second port array, and a third Wollaston prism coupled to the third port array. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
This is a division of U.S. application Ser. No. 08/957,316, filed Oct. 23, 1997, which is a continuation of U.S. application Ser. No. 08/703,015, filed Aug. 26, 1996, now abandoned, which is a division of U.S. application Ser. No. 08/467,039, filed Jun. 6, 1995, now abandoned.
BACKGROUND OF THE INVENTION
The invention relates in general to a movable barrier operator for opening and closing a movable barrier or door. More particularly, the invention relates to a garage door operator that can learn force and travel limits when installed and can simulate the temperature of its electric motor to avoid motor failure during operation.
A number of garage door operators have been sold over the years. Most garage door operators include a head unit containing a motor having a transmission connected to it, which may be a chain drive or a screw drive, which is coupled to a garage door for opening and closing the garage door. Such garage door openers also have included optical detection systems located near the bottom of the travel of the door to prevent the door from closing on objects or on persons that may be in the path of the door. Such garage door operators typically include a wall control which is connected via one or more wires to the head unit to send signals to the head unit to cause the head unit to open and close the garage door, to light a worklight or the like. Such prior art garage door operators also include a receiver and head unit for receiving radio frequency transmissions from a hand-held code transmitter or from a keypad transmitter which may be affixed to the outside of the garage or other structure. These garage door operators typically include adjustable limit switches which cause the garage door to operate or to halt the motor when the travel of the door causes the limit switch to change state which may either be in the up position or in the down position. This prevents damage to the door as well as damage to the structure supporting the door. It may be appreciated, however, that with different size garages and different size doors, the limits of travel must be custom set once the unit is placed within the garage. In the past, such units have had mechanically adjustable limit switches which are typically set by an installer. The installer must go back and forth between the door, the wall switch and the head unit in order to make the adjustment. This, of course, is time consuming and results in the installer being forced to spend more time than is desirable to install the garage door operator.
A number of requirements are in existence from Underwriter's Laboratories, the Consumer Product Safety Commission and the like which require that garage door operators sold in the United States must, when in a closing mode and contacting an obstruction having a height of more than one inch, reverse and open the door in order to prevent damage to property and injury to persons. Prior art garage door operators also included systems whereby the force which the electric motor applied to the garage door through the transmission might be adjusted. Typically, this force is adjusted by a licensed repair technician or installer who obtained access to the inside of the head unit and adjusts a pair of potentiometers, one of which sets the maximal force to be applied during the closing portion of door operation, the other of which establishes the maximum force to be applied during the opening of door operation.
Such a garage door operator is exemplified by an operator taught in U.S. Pat. No. 4,638,443 to Schindler. However, such door operators are relatively inconvenient to install and invite misuse because the homeowner, using such a garage door operator, if the garage door operator begins to bind or jam in the tracks, may likely obtain access to the head unit and increase the force limit. Increasing the maximal force may allow the door to move passed a binding point, but apply the maximal force at the bottom of its travel when it is almost closed where, of course, it should not.
Another problem associated with prior art garage door operators is that they typically use electric motors having thermostats connected in series with portions of their windings. The thermostats are adapted to open when the temperature of the winding exceeds a preselected limit. The problem with such units is that when the thermostats open, the door then stops in whatever position it is then in and can neither be opened or closed until the motor cools, thereby preventing a person from exiting a garage or entering the garage if they need to.
SUMMARY OF THE INVENTION
The present invention is directed to a movable barrier operator which includes a head unit having an electric motor positioned therein, the motor being adapted to drive a transmission connectable to the motor, which transmission is connectable to a movable barrier such as a garage door. A wired switch is connectable to the head unit for commanding the head unit to open and close the door and for commanding a controller within the head unit to enter a learn mode. The controller includes a microcontroller having a non-volatile memory associated with it which can store force set points as well as digital end of travel positions within it. When the controller is placed in learn mode by appropriate switch closure from the wall switch, the door is caused to cycle open and closed. The force set point stored in the non-volatile memory is a relatively low set point and if the door is placed in learn mode and the door reaches a binding position, the set point will be changed by increasing the set point to enable the door to travel through the binding area. Thus, the set points will be dynamically adjusted as the door is in the learn mode, but the set points will not be changeable once the door is taken out of the learn mode, thereby preventing the force set point from being inadvertently increased, which might lead to property damage or injury. Likewise, the end of travel positions can be adjusted automatically when in the learn mode because if the door is halted by the controller, when the controller senses that the door position has reached the previously set end of travel position, the door will then be commanded by a button push from the wall switch to keep travelling in the same direction, thereby incrementing or changing. The end of travel limits are set by pushing the learn button on the wall switch which causes the door to travel upward and continue travelling upward until the door has travelled as far as the installer wishes it to travel. The installer disables the learn switch by lifting his hand from the button. The up limit is then stored and the door is then moved toward the closed position. A pass point or position normalizing system consisting of a ring-like light interrupter attached to the garage door crosses the light path of an optical obstacle detector signalling instantaneously the position of the door and the door continues until it closes, whereupon force sensing in the door causes an auto-reverse to take place and then raises the door to the up position, the learn mode having been completed and the door travel limits having been set.
The movable barrier operator also includes a combination of a temperature sensor and microcontroller. The temperature sensor senses the ambient temperature within the head unit because it is positioned in proximity with the electric motor. When the electric motor is operated, a count is incremented in the microcontroller which is multiplied by a constant which is indicative of the speed at which the motor is moving. This incremented multiplied count is then indicative of the rise in temperature which the motor has experienced by being operated. The count has subtracted from it the difference between the simulated temperature and the ambient temperature and the amount of time which the motor has been switched off. The totality of which is multiplied by a constant. The remaining count then is an indication of the extant temperature of the motor. In the event that the temperature, as determined by the microcontroller, is relatively high, the unit provides a predictive function in that if an attempt is made to open or close the garage door, prior to the door moving, the microcontroller will make a determination as to whether the single cycling of the door will add additional temperature to the motor causing it to exceed a set point temperature and, if so, will inhibit operation of the door to prevent the motor from being energized so as to exceed its safe temperature limit.
The movable barrier operator also includes light emitting diodes for providing an output indication to a user of when a problem may have been encountered with the door operator. In the event that further operation of the door operator will cause the motor to exceed its set point temperature, an LED will be illuminated as a result of the microcontroller temperature prediction indicating to the user that the motor is not operating because further operation will cause the motor to exceed its safe temperature limits.
It is a principal aspect of the present invention to provide a movable barrier operator which is able to quickly and automatically select end of travel positions.
It is another aspect of the present invention to provide a movable barrier operator which, upon installation, is able to quickly establish up and down force set points.
It is still another aspect of the present invention to provide a movable barrier operator which can determine the temperature of the motor based upon motor history and the ambient temperature of the head unit.
Other aspects and advantages of the invention will become obvious to one of ordinary skill in the art upon a perusal of the following specification and claims in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a garage having mounted within it a garage door operator embodying the present invention;
FIG. 2 is a block diagram of a controller mounted within the head unit of the garage door operator employed in the garage door operator shown in FIG. 1;
FIG. 3 is a schematic diagram of the controller shown in block format in FIG. 2;
FIG. 4 is a schematic diagram of a receiver module shown in the schematic diagram of FIG. 3;
FIGS. 5A-B are a flow chart of a main routine that executes in a microcontroller of the control unit;
FIGS. 6A-G are a flow diagram of a learn routine executed by the microcontroller;
FIGS. 7A-B are flow diagrams of a timer routine executed by the microcontroller;
FIGS. 8A-B are flow diagrams of a state routine representative of the current and recent state of the electric motor;
FIGS. 9A-B are a flow chart of a tachometer input routine and also determines the position of the door on the basis of the pass point system and input from the optical obstacle detector;
FIGS. 10A-C are flow charts of the switch input routines from the switch module; and
FIG. 11 is a schematic diagram of the switch module and the switch biasing circuit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and especially to FIG. 1, more specifically a movable barrier door operator or garage door operator is generally shown therein and referred to by numeral 10 includes a head unit 12 mounted within a garage 14. More specifically, the head unit 12 is mounted to the ceiling of the garage 14 and includes a rail 18 extending therefrom with a releasable trolley 20 attached having an arm 22 extending to a multiple paneled garage door 24 positioned for movement along a pair of door rails 26 and 28. The system includes a hand-held transmitter unit 30 adapted to send signals to an antenna 32 positioned on the head unit 12 and coupled to a receiver as will appear hereinafter. An external control pad 34 is positioned on the outside of the garage having a plurality of buttons thereon and communicates via radio frequency transmission with the antenna 32 of the head unit 12. A switch module 39 is mounted on a wall of the garage. The switch module 39 is connected to the head unit by a pair of wires 39a. The switch module 39 includes a learn switch 39b, a light switch 39c, a lock switch 39d and a command switch 39e. An optical emitter 42 is connected via a power and signal line 44 to the head unit 12. An optical detector 46 is connected via a wire 48 to the head unit 12. A pass point detector 49 comprising a bracket 49a and a plate structure 49b extending from the bracket has a substantially circular aperture 49c formed in the bracket, which aperture might also be square or rectangular. The pass point detector is arranged so that it interrupts the light beam on a bottom leg 49d and allows the light beam to pass through the aperture 49c. The light beam is again interrupted by the leg 49e, thereby signalling the controller via the optical detector 46 that the pass point detector attached to the door has moved past a certain position allowing the controller to normalize or zero its position, as will be appreciated in more detail hereinafter.
As shown in FIGS. 2 and 3, the garage door operator 10, which includes the head unit 12 has a controller 70 which includes the antenna 32. The controller 70 includes a power supply 72 which receives alternating current from an alternating current source, such as 110 volt AC, and converts the alternating current to +5 volts zero and 24 volts DC. The 5 volt supply is fed along a line 74 to a number of other elements in the controller 70. The 24 volt supply is fed along the line 76 to other elements of the controller 70. The controller 70 includes a super-regenerative receiver 80 coupled via a line 82 to supply demodulated digital signals to a microcontroller 84. The receiver is energized by a line 85 coupled to the line 74. The microcontroller 84 is also coupled by a bus 86 to a non-volatile memory 88, which non-volatile memory stores set points and other customized digital data related to the operation of the control unit. An obstacle detector 90, which comprises the emitter 42 and infrared detector 46 is coupled via an obstacle detector bus 92 to the microcontroller 84. The obstacle detector bus 92 includes lines 44 and 48. The wall switch 39 is connected via the connecting wires 39a to a switch biasing module 96 which is powered from the 5 volt supply line 74 and supplies signals to and is controlled by the microcontroller 84 via a bus 100 coupled to the microcontroller 84. The microcontroller 84, in response to switch closures, will send signals over a relay logic line 102 to a relay logic module 104 connected to an alternating current motor 106 having a power take-off shaft 108 coupled to the transmission 18 of the garage door operator. A tachometer 110 is coupled to the shaft 108 and provides a tachometer signal on a tachometer line 112 to the microcontroller 84, the tachometer signal being indicative of the speed of rotation of the motor.
The power supply 72 includes a transformer 130 which receives alternating current on leads 132 and 134 from an external source of alternating current. The transformer steps down the voltage to 24 volts and feeds 24 volts to a pair of capacitors 138 and 140 which provide a filtering function. A 24 volt filtered DC potential is supplied on the line 76 to the relay logic 104. The potential is fed through a resistor 142 across a pair of filter capacitors 144 and 146, which are connected to a 5 volt voltage regulator 150, which supplies regulated 5 volt output voltage across a capacitor 152 and a Zener diode 154 to the line 74.
Signals may be received by the controller at the antenna 32 and fed to the receiver 80. The receiver 80 includes a pair of inductors 170 and 172 and a pair of capacitors 174 and 176 that provide impedance matching between the antenna 32 and other portions of the receiver. An NPN transistor 178 is connected in common base configuration as a buffer amplifier. Bias to the buffer amplifier transistor 178 is provided by resistors 180 and 81. A resistor 188, a capacitor 190, a capacitor 192 and a capacitor 194 provide filtering to isolate a later receiver stage from the buffer amplifier 178. An inductor 196 also provides power supply buffering. The buffered RF output signal is supplied on a line 200, coupled between the collector of the transistor 178 and a receiver module 202 which is shown in FIG. 4. The lead 204 feeds into the unit 202 and is coupled to a biasing resistor 220. The buffered radio frequency signal is fed via a coupling capacitor 222 to a tuned circuit 224 comprising a variable inductor 226 connected in parallel with a capacitor 228. Signals from the tuned circuit 224 are fed on a line 230 to a coupling capacitor 232 which is connected to an NPN transistor 234 at its based 236. The transistor has a collector 240 and emitter 242. The collector 240 is connected to a feedback capacitor 246 and a feedback resistor 248. The emitter is also coupled to the feedback capacitor 246 and to a capacitor 250. The line 210 is coupled to a choke inductor 256 which provides ground potential to a pair of resistors 258 and 260 as well as a capacitor 262. The resistor 258 is connected to the base 236 of the transistor 234. The resistor 260 is connected via an inductor 264 to the emitter 242 of the transistor. The output signal from the transistor is fed outward on a line 212 to an electrolytic capacitor 270.
As shown in FIG. 3, the capacitor 270 capacitively couples the demodulated radio frequency signal to a bandpass amplifier 280 to an average detector 282 which feeds a comparator 284. The comparator 284 also receives a signal directly from the bandpass amplifier 280 and provides a demodulated digital output signal on the line 82 coupled to the P32 pin of the Z86E21/61 microcontroller 84. The microcontroller 84 is energized by the power supply 72 and also controlled by the wall switch 39 coupled to the microcontroller by the leads 100.
From time to time, the microcontroller will supply current to the switch biasing module 96.
The microcontroller operates under the control of a main routine as shown in FIGS. SA and 5B. When the unit is powered up, a power on reset is performed in a step 300, the memory is cleared and a check sum from read-only memory within the microcontroller 84 is tested. In a step 302, if the check sum and the memory prove to be correct, control is transferred to a step 304, if not, control is transferred back to the step 300. The last non-volatile state, which is indicative of the state of the operator, that is whether the operator indicated the door was at its up limit, down limit or in the middle of its travel, is tested for in a step 304 and if the last state is a down limit, control is transferred to a step 306. If it was an up limit, control is transferred to a step 308. If it was neither a down nor an up limit, control is transferred to a step 310. In the step 306, the position is set as the down limit value and a window flag is set. The operation state is set as down limit. In a step 308, the position is set as up, the window flag is set and the operation state is set as up limit. In the step 310, the position is set as outside the normal range, 6 inches below the secondary up limit. The operation state is set as stopped. Control is transferred from any of steps 306, 308 and 310 to a step 312 where a stored simulated motor temperature is read from the non-volatile memory 88. The temperature of a printed circuit board positioned within the head unit is read from the temperature sensor 120 which is supplied over a line 120a to the microcontroller. In order to read the PC board temperature, a pin P20 of the microprocessor 84 is driven high, causing a high potential to appear on a line 120b which supplies a current through the RTD sensor 120 to a comparator 120c. A capacitor 120d connected to the comparator and to the temperature sensor, is grounded and charges up. The other input terminal to the comparator has a voltage divider 120e connected to it to supply a reference voltage of about 2.5 volts. Thus, the microcontroller starts a timer running when it brings line 120b high and interrogates a line 120f to determine its state. The line 120f will be driven high when the temperature at the junction of the RTD 120 and the capacitor 120d exceeds 2.5 volts. Thus, the time that it takes to charge the capacitor through the resistance is indicative of the temperature within the head unit and, in this manner, the PC board temperature is read and if the temperature as read is greater than the temperature retrieved from the non-volatile memory, the temperature read from the PC board is then stored as the motor temperature.
In a step 314, constants related to the receipt and processing of the demodulated signal on the line 82 are initialized. In a step 316, a test is made to determine whether the learn switch 39b had been activated within the last 30 seconds. If it has not, control is transferred back to the step 314.
In a step 318, a test is made to determine whether the command switch debounce timer has expired. If it has, control is transferred to a step 320. If it is not, control is transferred back to the step 314. In the step 320, the learn limit cycle is begun as will be discussed in more detail as to FIGS. 6A through 6G. The main routine effectively has a number of interrupt routines coupled to it. In the event that a falling edge is detected on the line 112 from the tachometer, an interrupt routine related to the tachometer is serviced in the step 322. A timer interrupt occurs every 0.5 millisecond in a step 324 as shown in FIGS. 7A through 7B.
The obstacle detector 90 generates a pulse every 10 milliseconds during the time when the beam from the infrared emitter 42 has not been interrupted either by the pass point system 49 or by an obstacle, in a step 326 following which the obstacle detector timer is cleared in a step 328.
As shown in FIGS. 10A through 10C, operation of the switch biasing module 96 is controlled over the lines 100 by the microcontroller 84. The microcontroller 84, in the step 340, tests to determine whether an RS232 digital communications mode has been set. If it has, control is transferred to a step 342, as shown in FIG. 10C, testing whether data is stored in an output buffer to be output from the microcontroller 84. If it is, control is transferred to a step 344 outputting the next bit, which may include a start bit, from the output buffer and control is then transferred back to the main routine. In the event that there is no data in the data buffer, control is transferred to the step 346, testing whether data is being received over lines 100. If it is being received, control is transferred to a step 348 to receive the next bit into the input buffer and the routine is then exited. If not, control is transferred to a step 350. In the step 350, a test is made to determine whether a start bit for RS232 signalling has been received. If it has not, control is transferred to a return step 352. If it has, control is transferred to a step 354 in which a flag is set indicating that the start bit has been received and the routine is exited. As shown in FIG. 10A, if the response to the decision block 340 is no, control is transferred to a decision step 360. The switch status counter is incremented and then a test is determined as to whether the contents of the counter are 29. If the switch counter is 29, control is transferred to a step 362 causing the counter to be zeroed. If the counter is not 29, control is transferred to a step 364, testing for whether the switch status is equal to zero. If the switch status is equal to zero, control is transferred to a step 366. In a step 366, a current source transistor 368, shown in FIG. 11, is switched on, drawing current through resistors 370 and 372 and feeding current out through a line 39a connected thereto to the switch module 39 and, more specifically, to a resistor 380, a 0.10 microfarad capacitor 382, a 1 microfarad capacitor 384, a 10 microfarad capacitor 386 and a switch terminal 388. The switch 39e is coupled to the switch terminal 388. The switch 39d may be selectively coupled to the capacitor 386. The switch 39b may be selectively coupled to the capacitor 384. The switch 39c may be selectively coupled to the capacitor 382. A light emitting diode 392 is connected to the resistor 380. Current flows through the resistor 380 and the light emitting diode 392 back to another one of the lines 39a and through a field effect transistor 398 to ground. In step 402, the sense input on a line 100 coupled to the transistor 398 is tested to determine whether the input is high. If the input is high immediately, that is indicative of the fact that switches 39b through 39e are all open and in a step 404, debounce timers are decremented for all switches and a got switch flag is set and the routine is exited in the event that the test of step 402 is negative. Control is then transferred to a step 406 testing after 10 microseconds if the sense in output on the line 100 connected to the field effect transistor 398 is high, which would be indicative of the switch 39c having been closed. If it is high, step 408 indicates the worklight timer is incremented, all other switch timers are decremented, the got switch flag is set and the routine is exited. In the event that the decision in step 406 is in the negative, control is transferred to a step 410 and the routine is exited. In the event that the decision from step 364 is in the negative, control is transferred to a step 412 wherein the switch status is tested as to whether it is equal to one. If it is, control is transferred to a step 414 testing whether the sensed input on the line 100 connected to the field effect transistor is high. If it is, control is transferred to step 416 to determine if the got switch flag is set. If it is, control is transferred to a step 418, where the learn switch debouncer is incremented, all other switch counters are decremented, the got switch flag is set and the routine is exited. In the event that the answer to step 414 or 416 is in the negative, control is transferred to a return step 420.
In the event that the answer to step 412 is in the negative, control is transferred to a step 422, as shown in FIG. 10B. A test is made as to whether the switch status is equal to 10. If it is, control is transferred to a step 424 where the sense out input is tested as high.
Thus, the charging rate for the capacitors which, in effect, is sensed on the line 100 connected to the field effect transistor 398 which is coupled to ground, is indicative of which of the switches is closed because the switch 39c has a capacitor that charges at 10 times the rate of the capacitor 384 connected to 39b and 100 times the rate of the capacitor 386 selectively couplable to switch 39d.
After the switch measurement has been made, the transistor 368 is switched non-conducting by the line 368b and the field effect transistor 398 is switched non-conducting by a line 450 connected to its gate. A transistor 462, coupled via a resistor 464 to a line 466, is switched on, biasing a transistor 468 on, causing current to flow through a diagnostic light emitting diode 470 to a field effect transistor 472 which is switched on via a voltage on a line 474. In addition, the capacitors 386, 384 and 382, which may have been charged are discharged through the field effect transistor 472.
In order to perform all of the switching functions after the step 424 has been executed, control is transferred to a step 510 testing whether the got switch flag has been cleared. If it has, control is transferred to a step 512 in which the command timer is incremented and all other timers are decremented and the got switch flag is set and the routine is exited. If the got switch flag has not been cleared as detected in the step 510, the routine is exited in the step 514. In the event that the sense input is measured as being high in the step 424, control is transferred to a step 516 where the vacation or lock flag counter is incremented and all other counters are decremented. The got switch flag is set and the routine is exited. In the event that the switch status equal 10 test in the step 422 is indicated to be no, control is then transferred to a step 520 testing whether the switch status is 11. If the switch status is 11, indicating that the routine has been swept through 11 times, control is transferred to a step 522 in which the field effect transistors 398 and 472 are both switched on, providing ground pads on both sides of the capacitors causing the capacitors to discharge and the routine is then exited. In the event that the step 520 test is negative, control is transferred to a step 524 testing whether the routine has been executed 15 times. If it has, control is transferred to a step 526 to determine if the bit which controls the status of light emitting diode 470, the diagnostic light emitting diode, has been set. If it has not been set, control is transferred to a step 528 wherein both transistors 368 and 468 are switched on and both the field effect transistors 398 and 472 are switched off. In order to test for short circuits between the source and drain electrodes of the field effect transistors 398 and 472 which might cause false operation signals to be supplied on the lines 100 to the microcontroller 84, resulting in inadvertent operation of the electric motor. The routine is then exited. In the event that the test in step 526 indicates that the diagnostic LED bit has been set, control is transferred to a step 530. In the step 530, the transistors 468 and 472 are switched on allowing current to flow through the diagnostic LED 470. In the event that the test in step 524 is negative, a test is made in a step 532 as to whether the routine has been executed 26 times. If it has not, the routine is exited in a step 534. If it has, both of the field effect transistors 398 and 372 are switched on to connect all of the capacitors to ground to discharge the capacitors and the routine is exited.
As shown in FIGS. 7A and 7B, when the timer interrupt occurs as in step 324, control is transferred to a step 550 shown in FIG. 7A wherein a test is made to determine whether a 2 millisecond timer has expired. If it has not, control is transferred to a step 552 determining whether a 500 millisecond timer has expired. If the 500 millisecond timer has expired, control is transferred to a step 554 testing whether power has been switched on through the relay logic 104 to the electric motor 106. If the motor has been switched on, control is transferred to a step 556 testing whether the motor is stalled, as indicated by the motor power having been switched on and by the fact that pulses are not coming through on the line 112 from the tachometer 110. In the event that the motor has stalled, control is transferred to a step 558. In the step 558 the existing motor temperature indication, as stored in one of the registers of the microcontroller 84, has added to it a constant which is related to a motor characteristic which is added in when the motor is indicated to be stalled. In the event that the response to the step 556 is in the negative, indicating that the motor is not stalled, control is transferred to a step 560 wherein the motor temperature is updated by adding a running motor constant to the motor temperature. In the event that the response to the test in step 554 is in the negative, indicating that motor power is not on and that heat is leaking out of the motor so that the temperature will be dropping, the new motor temperature is assigned as being equal to the old motor temperature, less the quantity of the old motor temperature, minus the ambient temperature measured from the RTD probe 120, the whole difference multiplied by a thermal decay fraction which is a number.
All of steps 558, 560 and 562 exit to a step 564 which test as to whether a 15 minute timer has timed out. If the timer has timed out, control is transferred to a step 566 causing the current, or updated motor temperature, to be stored in a non-volatile memory 88. If the 15 minute timer has not been timed out, control is transferred to a step 568, as shown in FIG. 7B. Step 566 also exits to step 568. A test is made in the step 568 to determine whether a obstacle detector interrupt has come in via step 326 causing the obstacle detector timer to have been cleared. If it has not, the period will be greater than 12 milliseconds, indicating that the obstacle detector beam has been blocked. If the obstacle detector beam, in fact, has been blocked, control is transferred to a step 570 to set the obstacle detector flag.
In the event that the response to step 568 is in the negative, the obstacle detector flag is cleared in the step 572 and control is transferred to a step 574. All operational timers, including radio timers and the like are incremented and the routine is exited.
In the event that the 2 millisecond timer tested for in the step 550 has expired, control is transferred to a step 576 which calls a motor operation routine. Following execution of the motor operation routine, control is transferred to the step 552. When the motor operation routine is called, as shown in FIG. 8A, a test is made in a step 580 to determine the status of the motor operation state variable which may indicate if the up limit or down limit has been reached, the motor is causing the door to travel up or down, the door has stopped in mid-travel or an auto-reverse delay indicating that the motor has stopped in mid-travel and will be switching into up travel shortly. In the event that there is an auto-reverse delay, control is transferred to a step 582, when a test is made for a command from one of the radio transmitters or from the wall control unit and, if so, the state of the motor is set indicating that the motor has stopped in mid-travel. Control is then transferred to a step 584 in which 0.50 second timer is tested to determine whether it has expired. If it has, the state is set to the up travel state following which the routine is exited in the step 586. In the event that the operation state is in the up travel state, as tested for in step 580, control is transferred to a step 588 testing for a command from a radio or wall control and if the command is received, the motor operational state is changed to stop in mid-travel. Control is transferred to a step 590. If the force period indicated is longer than that stored in an up array location, indicated by the position of the motor. The state of the door is indicated as stopped in mid-travel. Control is then transferred to a step 592 testing whether the current position of the door is at the up limit, then the state of the door is set as being at the up limit and control is transferred to a step 594 causing the routine to be exited, as shown in FIG. 8B.
In the event that the operational state tested for in the step 580 is indicated to be at the up limit, control is transferred to a step 596 which tests for a command from the radio or wall control unit and a test is made to determine whether the motor temperature is below a set point for the down travel motor temperature threshold. The state is set as being a down travel state. If the temperature value exceeds the threshold or set point temperature value, an output diagnostic flag is set for providing an output indication in another routine. Control is then transferred to a step 598, causing the routine to be exited. In the event that the down travel limit has been reached, control is transferred to a step 600 testing for whether a command has come in from the radio or wall control and, if it has, the state is set as auto-reverse and the auto-reverse timer is cleared. Control is then transferred to a step 602 testing whether the force period, as indicated, is longer than the force period stored in the down travel array for the current position of the door. Auto-reverse is then entered at step 582 on a later iteration of the routine. Control is transferred to a step 604 to test whether the position of the door is at the down limit position and the pass point detector has already indicated that the door has swept the passed the pass point, the state is set as a down limit state and control is transferred to a step 606 testing for whether the door position is at the down limit position and testing for whether the pass point has been detected. If the pass point has not been detected, the motor operational state is set to auto-reverse, causing auto-reverse to be entered in a later routine and control is transferred to a step 608, exiting the main routine.
In the event that the block 580 indicates that the door is at the down limit, control is transferred to a step 610, testing for a command from the radio or wall control and testing the current motor temperature. If the current motor temperature is below the up travel motor temperature threshold, then the motor state variable is set as equal to up travel. If the temperature is above the threshold or set point temperature, a diagnostic code flag is then set for later diagnostic output and control is transferred to a return step 612. In the event that the motor operational state is indicated as being stopped in mid-travel, control is transferred to a step 614 which tests for a radio or wall control command and tests the motor temperature value to determine whether it is above or below a down travel motor temperature threshold. If the motor temperature is above the travel threshold, then the door is left stopped in mid-travel and the routine is returned from in step 616.
In the event that the learn switch has been activated as tested for in step 316 and the command switch is being held down as indicated by the positive result from the step 318, the learn limit cycle is entered in step 320 and transfers control to a step 630, as shown in FIG. 6A. In step 630, the maximum force is set to a minimum value from which it can later be incremented, if necessary. The motor up and motor down controllers in the relay logic 104 are disabled. The relay logic 104 includes an NPN transistor 700 coupled to line 76 to receive 24 to 28 volts therefrom via a coil 702 of a relay 704 having relay contacts 706. A transistor 710 coupled to the microcontroller is also coupled to line 76 via a relay coil 714 and together comprise an up relay 718 which is connected via a lead 720 to the electric motor 106. A down transistor 730 is coupled via a coil 732 to the power supply 76. The down relay 732 has an armature 734 associated with it and is connected to the motor to drive it down. Respective diodes 740 and 742 are connected across coils 714 and 732 to provide protection when the transistors 710 and 730 are switched off. In the step 632, both the transistors 710 and 730 are switched off, interrupting either up motor power or down motor power to the electric motor 106 and the microcontroller delays for 0.50 second. Control is then transferred to a step 634, causing the relay 704 to be switched on, delivering power to an electric light or worklight 750 associated with the head unit. The up motor relay 716 is switched on. A 1 second timer is also started which inhibits testing of force limits due to the inertia of the door as it begins moving. Control is then transferred to a step 636, testing for whether the 1 second timer has timed out and testing for whether the force period is longer than the force limit setting. If both conditions have occurred, control is transferred to a step 640 as shown in FIG. 6B. If either the 1 second timer has not timed out or the force period is not longer than the force limit setting, control is transferred to a step 638 which tests whether the command switch is still being held down. If it is, control is transferred back to step 636. If it is not, control is transferred to the step 640. In step 640, both the up transistor 710 and the down transistor 730 are causing both the up motor and down motor command from the relay logic to be interrupted and a delay of 0.50 second is taken and the position counter is cleared. Control is then transferred to a step 641 in which the transistor 730 is commanded to switch on, starting the motor moving down and the 1 second force ignore timer is started running. A test is made in a step 642 to determine whether the command switch has been activated again. If it has, the force limit setting is increased in a step 644 following which control is then transferred back to the step 632. If the command switch is not being held down, control is then transferred to a step 646, testing whether the 1 second force ignore timer has timed out. The last 32 rpm pulses indicative of the force are ignored and a force period from the previous pulse is accepted as the down force. Control is then transferred to a step 648 and a test is made to determine whether the movable barrier is at the pass point as indicated by the pass point detector 49 interacting with the optical detector 46. Control is then transferred to a step 650. The position counter is complemented and the complemented value is stored as the up limit following which the position counter is cleared and a pass point flag is set. Control is then transferred back to the step 642. In the event that the result of the test in step 648 is negative, control is transferred to a step 652 which tests whether the 1 second force delay timer has expired and whether the force period is greater than the force limit setting, indicating that the force has exceeded. If both of those conditions have occurred, control is transferred to a step 654 which tests whether the pass point flag has been set. If it has not been set, control is transferred to a step 656, wherein the position counter is complemented and the complemented value is saved as the up limit and the position counter is cleared. In the event that the pass point flag has been set, control is transferred to a step 658. In the event that the test in step 652 has been negative, control is transferred to a step 660 which tests the value of the obstacle reverse flag. If the obstacle reverse flag has not been set, control is transferred to the step 642 shown on FIG. 6B. If the flag has been set, control is transferred to the step 654.
In a step 658, both transistors 710 and 730 are switched off interrupting up and down power from the relays to the electric motor 106 and halting the motor and the microcontroller 84 then delays for 0.50 second. Control is then transferred to a step 660. In step 660, the transistor 710 is switched on switching on the up relay causing the motor to be turned to drive the door upward and the 1 second force ignore timer is started. Control is transferred to a decision step 662 testing for whether the command switch is set. If the command switch is set, control is transferred back to the step 664 causing the force limit setting to be increased, following which control is transferred to the step 632, interrupting the motor outputs. If the command switch has not been set, control is transferred to the step 664 causing the maximum force from the 33rd previous reading to be saved as the up force, following which control is transferred to a decision block 666 which tests for whether the 1 second force ignore timer has expired and whether the force period is longer than the force limit setting. If both conditions are true, control is transferred to a step 668. If not, control is transferred to a step 670 which tests for whether the door position is at the up limit. If the door position is at the up limit, control is transferred to the step 668, switching off both of the motor outputs to halt the door and delaying for 0.50 second. If the position tested in step 670 is not at the upper limit, control is transferred back to the step 662. Following step 668 control is transferred to step 674, where the down output is turned on and the 1 second force ignore timer is started. Control is then transferred to the step 676 during which the command switch is tested. If the command switch is set, control is transferred back to the step 644 causing the force limit setting to be increased and ultimately to the step 632 which switches off the motor outputs and delays for 0.50 second. If the command switch has not been set, control is transferred to a step 678. If the position counter indicates that the door is presently at a point where a force transition normally occurs or where force settings are to change, and the 1 second force ignore timer has expired, the 33rd previous maximum force is stored and the down force array is filled with the last 33 force measurements. Control is then transferred to a step 680 which tests for whether the obstacle detector reverse flag has been set. If it has not been set, control is transferred to a step 682 which tests for whether the 1 second force ignore timer has expired and whether the force period is longer than the force limit setting. If both those conditions are true, control is transferred to a step 684 which tests for the pass point being set. If the pass point flag was not set, control is transferred to the step 688. In the event that the obstacle reverse flag is set, control is also transferred to the step 686, and then to 688. In the event that the decision block 682 is answered in the negative, control is transferred back to the step 676. If the pass point flag has been set as tested for in the step 684, control is transferred to the step 686 wherein the current door position is saved as the down limit position. In step 688, both the motor output transistors 710 and 730 are switched off, interrupting up and down power to the motor and a delay occurs for 0.50 second. Control is then transferred to the step 690 wherein the up transistor 710 is switched on, causing the up relay to be actuated, providing up power to the motor and the 1 second force ignore timer begins running. In the step 692, a test is made for whether the command has been set again. If it has, control is transferred back to the step 644, as shown in FIG. 6B, and following that to the step 632, as shown in FIG. 6A. If the command switch has not been set, control is transferred to the step 694 which tests for whether the position counter indicates that the door is at a sectional force transition point or barrier and the 1 second force ignore timer has expired. If both those conditions are true, the maximum force from the last sectional barrier is then loaded. Control is then transferred to a decision step 696 testing for whether the 1 second force ignore timer has timed out and whether the force period is indicated to be longer than the force period limit setting. If both of those conditions are true, control is then transferred to a step 698 causing the motor output transistors 710 and 730 to be switched off and all data is stored in the non-volatile memory 88 and the routine is exited. In the event that decision is indicated to be in the negative from the decision step 696, control is transferred to a step 697 which tests whether the door position is presently at the up limit position. If it is, control is then transferred to the step 698. If it is not, control is transferred to the step 692.
In the event that the rpm interrupt step 322, as shown in FIG. 5B, is executed, control is then transferred to a step 800, as shown in FIG. 9A. In step 800, the time duration from the last rpm pulse from the tachometer 110 is measured and saved as a force period indication. Control is then transferred to a decision block. Control is transferred to the step 802, in which the operator state variable is tested. In the event that the operator state variable indicates that the operator is causing the door to travel down, the door is at the down limit or the door is in the auto-reverse mode, control is transferred to a step 804 causinc the door position counter to be incremented. In the event that the door operator state indicates that the door is travelling upward, has reached its up limit or has stopped in mid-travel, control is transferred to a step 806 which causes the position counter to be decremented. Control is then transferred to a decision step 808 in which the pass point pattern testing flag is tested for whether it is set. If it is set, control is transferred to a step 810 which tests a timer to determine whether the maximum pattern time allotted by the system has expired. In the event that the pass point pattern testing flag is not set, control is transferred to a step 812, testing for whether the optical obstacle detector flag has been set. If it is not set, the routine is exited in a step 814. If the obstacle detector flag has been set, control is transferred to a step 816 wherein the pattern testing flag is set and the routine is exited. In the event that the maximum pattern time has timed out, as tested for in the step 810, control is transferred to a step 820 wherein the optical reverse flag is set and the routine is exited. In the maximum pattern time has not expired, a test is made in a step 822 for whether the microcontroller has sensed from the obstacle detector that the beam has been blocked open within a correct timing sequence indicative of the pass point detection system. If it has not, the routine is exited in a step 824. If it has, control is transferred to a step 826. Testing for whether a window flag has been set. As to whether the rough position of the door would indicate that the pass point should have been encountered. If the window flag has been set, control is transferred to a step 828, testing for whether the position is within the window flag position. If it has, control is transferred to a step 832, causing the position counter to be cleared or renormalized or zeroed, setting the window flag and set a flag indicating that the pass point has been found, following which the routine is exited. In the event that the position is not within the window as tested for in step 828, the obstacle reverse flag is set in a step 830 and the routine is exited. In the event that the test made in step 326 indicates that the window flag has not been set, control is then transferred directly to the step 832.
While there has been illustrated and described a particular embodiment of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention. | A movable barrier operator includes a wall control switch module having a learn switch thereon. The switch module is connectable to a control unit positioned in a head of a garage movable barrier operator. The head unit also contains an electric motor which is connected to a transmission for opening and closing a movable barrier such as a garage door. The switch module includes a plurality of switches coupled to capacitors which, when closed, have varying charge and discharge times to enable which switch has been closed. The control unit includes an automatic force incrementing system for adjusting the maximal opening and closing force to be placed upon the movable barrier during a learn operation. Likewise, end of travel limits can also be set during a learn operation upon installation of the unit. The movable barrier operator also includes an ambient temperature sensor which is used to derive a motor temperature signal, which motor temperature signal is measured and is used to inhibit motor operation when further motor operation exceeds or is about to exceed set point temperature limits. | 4 |
FIELD OF THE INVENTION
The present invention relates to the production of subterranean fluids and, in particular, to a process and apparatus for completing a well in an unconsolidated hydrocarbon-bearing formation.
BACKGROUND OF THE INVENTION
To recover valuable fluids from subterranean formations, wells are drilled from the surface of the earth to the productive formations. In the drilling of such wells, a rotating drill bit is commonly employed. As the bit rotates, penetrating through to the formation, material is dislodged in the form of cuttings. These cuttings are commonly removed from the well during the drilling operation by means of a drilling fluid, which may be comprise water, oil, an emulsion of water and oil or foam. The drilling fluid is circulated downward through the drill pipe and upward through the annulus between the drill pipe and the wall of the well, carrying the cuttings with it to the surface of the well in the form of a slurry. The drilling fluid also serves to cool the drill bit and can prevent blow-outs when drilling into strata containing high pressure fluids. When drilling a well, it is common to start with a relatively large diameter hole and cement surface casing in the hole. Subsequent drilling operations are then conducted through this casing. As drilling progresses deeper into the well, the diameter of the hole drilled may be reduced in steps, with progressively smaller diameters of casing employed in response thereto.
In seeking to recover hydrocarbon-bearing fluids from subterranean formations, it is often the case that such fluids are found to reside within formations which are unconsolidated. Unconsolidated formations often comprise poorly cemented sandstone which have little or no cementing material holding the grains of sand together. The production of hydrocarbons from unconsolidated formations often results in the concomitant production of sand. As those skilled in the art readily appreciate, the production of sand is undesirable for many reasons, chief among these being that it is abrasive to the components within the well, such as tubing, pumps, valves and the like, causing rapid erosion of such equipment and, in addition, may result in the partial or complete blockage of the well. Sand production is often rate sensitive, that is, no sand may be produced at very low rates of production, while at higher rates, large amounts of sand may be produced.
A variety of techniques have been employed to control the flow of sand from unconsolidated formations. Many of these techniques employ the use of slotted or screened liners or gravel packs to prevent the sand from being transported along with the hydrocarbons into the well. For example, in the heavy oil sands of California, well completions generally employ slotted liners. Typically, the slotted liner is drilled into the producing zone of the formation with foam, to a predetermined depth. Advantages accruing from the use of foamed-in liner completions include: reduced drilling expense, increased production and the bio-degradability typical of such foams. However, these well completions, without being gravel packed across the unconsolidated producing zone, experience higher operational costs due to produced formation sand.
In certain situations, when attempting to install a gravel packed liner in an unconsolidated formation, a variety of problems can be encountered. One such problem arises when attempting to underream a drilled pilot hole with foam prior to gravel packing. As is often the case, when conducting a conventional underreaming operation, the underreamed hole will collapse before the liner is positioned for gravel packing due to the unconsolidated nature of the formation and the fact that the underreaming tool must be removed before the gravel pack is installed.
Underreamers are a type of borehole tool which is used to enlarge a borehole which has already been drilled. In an underreaming operation, an expandable drilling tool is introduced through the casing to the point where underreaming is to be conducted. There, the underreamer is expanded to drill the formation to a larger diameter than the hole through which the underreamer passed. A typical underreamer includes expandable arms mounted in a housing by hinge pins for movement between a closed position and an open, expanded position. In the usual case, the expandable arms are moved outwardly by means of a pressure activated piston mounted within the main bore of the tool's housing. Underreamers come in a variety of types. One type of underreamer employs rotatable cone bits, mounted on the ends of the expandable arms for engaging certain types of formation and is generally referred to as a roller cone underreamer. Another earlier type of underreamer is known as a drag bit underreamer. In the drag bit underreamer, the expandable arms have a machined surface which is typically coated with a hard facing material for engaging and enlarging a borehole after the initial hole has been cut. The machined surface may have diamond bit implants such as those manufactured by General Electric under the trademark "Stratapax". As is known in the art, underreamers may be mounted at the end of the drill string or, in the case of a drilling type underreamer, mounted in the drill string ahead of the drill bit.
Despite these advances in the art, there exists a need for an apparatus and method capable of placing a liner and gravel pack in an unconsolidated formation in a single trip into the well.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a process for forming a hole within an unconsolidated hydrocarbonaceous fluid-bearing formation, installing a slotted liner and gravel packing the liner in a single trip into the formation. The process includes the steps of: drilling a bore hole to a first predetermined depth above the hydrocarbonaceous fluid producing zone; installing a well casing in the bore hole to about the first predetermined depth; lowering on a pipe string through the bore hole an apparatus for drilling and installing a slotted liner to be gravel packed, the apparatus including a drill bit for drilling a pilot hole, means for enlarging the pilot hole to a diameter larger than the internal diameter of the well casing and sufficient for gravel packing, the pilot hole enlarging means being initially retracted and located within a housing above the pilot hole drill bit, a slotted liner having a first end and a second end, the first end integrally joined to the apparatus above the housing and a drive assembly joined to the second end of the slotted liner; rotating the apparatus to drill a pilot hole through the hydrocarbonaceous fluid producing zone; expanding the initially retracted pilot hole enlarging means upon exceeding the first pre-determined depth; enlarging the pilot hole to a diameter larger than the internal diameter of the well casing and sufficient for gravel packing; continuing until the first end of the slotted liner reaches a second pre- determined depth, the second pre-determined depth sufficient to place the slotted liner within the hydrocarbonaceous fluid producing zone; reversing the direction of circulation down an annulus defined by the well casing and drill pipe and injecting a gravel slurry through the drill pipe and into an annulus defined by the enlarged hole and slotted liner to gravel pack the annulus.
Also provided is an apparatus for drilling and installing a slotted liner and gravel packing the liner in a single trip into an unconsolidated hydrocarbonaceous fluid-bearing formation. The apparatus includes a drill bit for drilling a pilot hole; a housing mounted above the pilot hole drill bit; means for enlarging a pilot hole, the pilot hole enlarging means pivotally mounted within the housing and capable of pivoting between a retracted position and an expanded position for enlarging the pilot hole to a diameter larger than the pilot hole and sufficient for gravel packing; a slotted liner having a first end and a second end, the first end joined to the apparatus above the underreaming bit housing; and a drive assembly joined to the second end of the slotted liner.
Therefore it is an object of the present invention to provide an improved process for forming a pilot hole, enlarging the pilot hole to a diameter larger than the pilot hole and the internal diameter of the well casing, installing a gravel pack within an unconsolidated hydrocarbonaceous fluid-bearing formation.
It is another object of the present invention to provide a process for forming a pilot hole, enlarging the pilot hole to a diameter larger than the pilot hole and the internal diameter of the well casing, and installing a slotted liner and gravel packing the slotted liner in a single trip into the well.
It is a further object of the present invention to provide an apparatus for drilling and installing a slotted liner for gravel packing.
Other objects and the several advantages of the present invention will become apparent to those skilled in the art upon a reading of the specification and the claims appended thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference may now be had to the following detailed description of exemplary embodiments of the invention, taken in conjunction with the accompanying drawings, in which:
FIG. 1 presents an apparatus for drilling and installing a slotted liner for gravel packing, in accordance with the present invention, showing two roller cone-type underreaming bits.
FIGS. 2A-D show the apparatus of FIG. 1 within an unconsolidated formation, in partial cut-away, at various stages of the process of the present invention.
FIG. 3 presents an alternate means for enlarging a pilot hole including two drag-type underreaming blades, shown in the retracted position and a preferred mechanism for expanding the drag blades.
FIG. 4 shows the mechanism of FIG. 3 with the drag blades locked in the fully expanded position.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is beet understood by reference to the appended figures, which are given by way of example and not of limitation.
Referring now to FIG. 1, an apparatus 10 for drilling and installing a gravel-packed liner is shown, in accordance with the present invention. Apparatus 10 includes a drill bit 12 for drilling a pilot hole, drill bit 12 attached to the bottom of bit shank 14. Apparatus 10 employs a seal bore and check valve assembly 36 and 37 to allow a tubing tail 34 to pass through to conduct drilling fluid circulation through the bit 12. As those skilled in the art appreciate, a wide variety of drilling fluids are known and readily available. Included among those drilling fluids suitable for use in the practice of the present invention are aqueous-based polymeric solutions, filtered water and preformed foams. Particularly preferred in many applications are the foam-based drilling fluids. Welded to the top of bit shank 14 is housing 18. Housing 18 serves to at least partially enclose a pilot hole enlarging means, which in the embodiment depicted in FIGS. 1 and 2 is a pair of roller-cone underreaming bits 20. While a pair of roller cone underreaming bits are shown in the embodiment of FIGS. 1 and 2, it is to be understood that one, two, three or more roller cone underreaming bits 20 may be effectively used in apparatus 10 in order to enlarge the pilot hole drilled by bit 12. The use of two roller cone underreaming bits 20 is particularly preferred in the practice of the present invention. Roller cone underreaming bits 20 are affixed at the ends of bit arms 21, bit arms 21 used to expand and retract roller cone bits 20, as may be easily envisioned. Roller-cone underreaming bits 20 enter housing 18 through slots 22 when the roller-cone underreaming bits 20 are in the initially retracted position. When in the expanded position, roller-cone underreaming bits 20 are employed to enlarge a pilot hole to a diameter sufficient for gravel packing.
Welded to the top of housing 18 is a slotted production liner 24 having a length appropriate for the particular production zone sought to be gravel packed. On top of the slotted liner 24 is a drive assembly 26 which may be welded to the slotted liner 24, as preferred, to allow liner rotation while drilling. Drive assembly 26 also permits the installation of a sand control packoff assembly (see FIGS. 2A-D) after the slotted liner 24 is set at its desired depth. Drive assembly 26 includes drill-in nipple 28 to which is attached drive tool 30 which consists of drill pipe assembly 40, collet release 54, splines 50 and 52, and circulation ports 56 and 58, each of which is described in more detail below. Drive assembly 26, itself, is affixed to drill pipe 32. Splines 50 are provided on drive tool 30 for mating engagement with splines 52 of drive assembly 26. A collet release 54 is provided which enables the liner to be released off of after gravel packing is complete. Circulation ports 56 and 58 are provided for use during the clean-up operation.
Still referring to FIG. 1, it may be seen that a tubing tail 34 with expansion joint 35 runs from the crossover of drill pipe assembly 40 down through the length of apparatus 10. Drill pipe assembly 40 is comprised of tubing tail 34, an upper end of which is attached to expansion joint 35. The upper end of expansion joint 35 is welded or screwed onto a right-hand threaded nut (not shown) which is provided for mating with an internal threaded portion of drill-in nipple 28. Tubing tail 34 is also provided with an upper sleeve valve 60 and a lower sleeve valve 62 for use in controlling fluid flow during circulation and clean-up, as will be described in more detail below.
FIGS. 2A-D show the apparatus 10 of FIG. 1 placed within an unconsolidated formation at various stages of the process of the present invention. Referring now to FIG. 2A, apparatus 10 is shown, in partial cut-away, positioned just at its final depth within an unconsolidated formation UF. Surface casing 38 is shown set to the top of formation UF and cemented in place, as is customary. Apparatus 10 is shown with underreamer roller cone bits 20 in the expanded condition, with liner 24 having been drilled-in with foam F and pilot hole 41 underreamed to form annulus 42. Slotted liner 24 is shown in partial cut-away to expose a portion of tubing tail 34 and flexible seal 36. As shown, upper and lower sleeve valves 60 and 62, respectively, are in the closed condition, enabling the foam F to circulate out drill bit 12.
Referring now to FIG. 2B, apparatus 10 is shown, after the liner drill-in process is completed, with liner slot clean-up in progress. As may be seen, lower sliding sleeve valve 62 is in the open position and check valve 37 is in the closed position, permitting flow out lower sliding sleeve valve 62, through the interior of slotted liner 24, out through its slots and up through the annulus 42, the arrows indicated the direction of flow. Also, as shown, the remaining portion of pilot hole 41 and the lowermost portion of annulus 42 will close-up around the expendable underreamer roller cone bits 20, housing 18 and pilot hole bit 12, as is desired.
In operation, a small diameter ball (about 1.25") is dropped and pumped down the drill pipe 32, through the tubing tail 34, and seated in lower sliding sleeve valve 62. Hydraulic foam pressure is then applied to open lower sliding sleeve valve 62. Foam is then pumped down the drill pipe 32, tubing tail 34, and out the open lower sliding sleeve valve 62 to displace any fill (formation sand) that may be present above the sliding sleeve valve 62 and inside slotted liner 24. Foam is then circulated to the surface for a short period of time. In the event that circulation is not established through sliding sleeve 62, a larger ball (about 1.5" in diameter) would be dropped in the same manner to open the upper sleeve valve 60 to achieve clean-up. Upper sleeve valve 60 may be placed at any desired depth between the expansion joint 35 and the lower sliding sleeve valve 62.
Once clean foam returns are established, the direction of foam circulation is reversed with foam circulated down the drill pipe casing annulus (see FIG. 2C), with clean foam passing through the lower sliding sleeve valve 62, up the tubing tail 34 and drill pipe 32 to the surface.
FIG. 2C depicts apparatus 10, in partial cut-away, during gravel packing. Gravel-laden foam G is fed over the top and down through the annulus formed between apparatus 10 and casing 38, into underreamed annulus 42. Annulus 42 is shown having a fully packed section 100 and section 102 where packing is still progressing. Lower sleeve valve 62 is in the open position, with check valve 37 in the closed position, permitting foam F to flow into liner 24 through its slots and into lower sleeve valve 62, up through tubing tail 34 and out through the top of apparatus 10, as indicated by the arrows.
FIG. 2D shows apparatus 10, in partial cut-away, following the completion of the gravel packing step. Gravel pack P is shown fully completed and the slotted liner 24 released from drill-in nipple 28. Foam is circulated down into drill pipe 32, out through circulation ports 56 and 58 and out of the drill pipe casing annulus until clean foam exits the hole. Tubing tail 34 is then unstrung from apparatus 10 and removed. A sand control pack-off assembly, not shown, is then driven over the top of the drill-in nipple 28.
FIG. 3 presents an alternate means for enlarging a pilot hole for use in an apparatus for drilling and installing a gravel-packed liner 10, in accordance with the present invention. As shown, the means for enlarging a pilot hole employs a pair of underreaming drag blades 320, depicted in the partially expanded position. While a pair of underreaming drag blades are shown in FIG. 3, it is to be understood that one, two, three or more drag blades 320 may be effectively used to enlarge the pilot hole drilled by bit 12. The use of two drag blades 320 is particularly preferred in the practice of the present invention. As with the previously described embodiment of the present invention, when in the expanded position, underreaming drag blades 320 are employed to enlarge a pilot hole to a diameter sufficient for gravel packing.
Referring to the cut-away portion of FIG. 3, a preferred mechanism for expanding drag blades 320 is shown in schematic form. In operation, once housing 318 has reached the point at which underreaming is to be conducted, the underreamer drag blades 320 are expanded by the application of drilling fluid pressure and by hydraulically sliding a plunger 352 through the internal passageway 362 of housing 318 while rotating the apparatus, forcing drag-blades 320 out of slots 322 of housing 318. (As indicated above, particularly preferred are the foam-based drilling fluids). Drag blades 320 are locked open by the use of a shear pin 356, which may be loaded by spring 358 or by any suitable means (e.g. hydraulic pressure). Referring to FIG. 4, drag-blades 320 are shown locked in the expanded position by the interaction of spring-loaded shear pin 356 with key-way 364 of drag-blades 320. Once the drag-blades are placed in the expanded and locked position,.plunger 352 can be pumped down into a fluted assembly above the pilot hole drill bit by dropping a ball of about one inch in diameter, thus establishing a passage for circulation.
The following specific example is presented herein to illustrate particular embodiments of the present invention and hence is illustrative of this invention and not to be construed in a limiting sense.
EXAMPLE
This example demonstrates the ability of the apparatus and process of the present invention to foam-drill a gravel-packed liner completion in a single trip into the well, utilizing underreaming.
Prior to beginning the completion process, surface casing was set to the top of a selected formation and cemented. A service rig complete with blow-out equipment, foaming unit and power swivel was then rigged up on the well. The casing float collar and casing shoe were drilled out in a conventional manner with water and circulated clean.
An apparatus in accordance with the present invention was used, the apparatus including a 75/8" pilot hole drill bit welded to the bottom of the housing of the expendable underreamer. A seal bore with check valve to allow a tubing tail to pass through the liner joint to conduct all foam circulation out through the pilot hole bit was employed. An appropriate length of slotted production liner was welded to the top of the underreamer bit housing. On top of the slotted liner, a drive assembly is welded to the liner to allow liner rotation while drilling, permitting the installation of a sand control packoff assembly after the liner was set at desired depth. The complete liner and drill-in assembly was run into the well bore on drill pipe.
Once the hole opener has cleared the end of the casing the hole opener was expanded to 15". This was accomplished, as previously described, by hydraulically sliding a plunger through the hole opener while rotating the assembly, forcing the blades of the drag-type underreamer out. The blades of the underreamer were locked through the use of a shear pins. The liner was then foamed drilled and underreamed to the designated depth.
Once the desired depth was reached, the liner slots and underreamed hole were foamed clean for a short period of time. A small diameter ball (about 1.25") was dropped and pumped down the drill pipe, through the tubing tail, and seated in lower sliding sleeve valve. Hydraulic foam pressure was applied to open lower lit sliding sleeve valve. Foam was then pumped down the drill pipe, tubing tail, and out the open lower sliding sleeve valve to displace any fill (formation sand) that may have accumulated above the sliding sleeve valve and inside liner. Foam was then circulated to the surface for a short period of time.
As indicated above, in the event that circulation is not established through lower sliding sleeve valve, a larger ball (about 1.5" in diameter) would be dropped in the same manner to open the upper (back-up) sleeve valve to achieve the above described interior clean-up operation. Once clean foam returns are established, the direction of foam circulation is reversed with foam circulated down the drill pipe casing annulus, with clean foam returns through the upper sliding sleeve valve, up the tubing tail and drill pipe to the surface.
Gravel laden foam was pumped down the annulus defined by the casing and drill pipe to pack the open hole and liner annulus, with the drill pipe providing a return path for the gravel pack fluid, which, as indicated, was foam in this case. Upon completion of the gravel packing of the annulus, the liner was released and foam circulated through the circulation ports and out of the hole for clean-up. The tubing tail, liner drill-in assembly and drill pipe were then pulled out of the hole and a sand control pack-off assembly driven over the liner top for the completion of the well.
Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be utilized without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims. | A process and apparatus for forming a hole within an unconsolidated hydrocarbonaceous fluid-bearing formation, installing a slotted liner and gravel packing the liner in a single trip into the formation. The apparatus includes a drill bit for drilling a pilot hole; a housing mounted above the pilot hole drill bit; means for enlarging a pilot hole, the pilot hole -enlarging means pivotally mounted within the housing and capable of pivoting between a retracted position and an expanded position for enlarging a pilot hole to a diameter larger than the pilot hole and sufficient for gravel packing; a slotted liner having a first end and a second end, the first end joined to the apparatus above the housing; and a drive assembly joined to the second end of the slotted liner. | 4 |
[0001] This application claims the benefit of Korean Application No. P2004-39567, filed on Jun. 1, 2004, which is 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 gasket provided between a door and a tub of a washing machine.
[0004] 2. Discussion of the Related Art
[0005] A washing machine is to wash the laundry using a chemical action by detergents and a mechanical impact by a drum. Generally, the washing machine includes a tub provided in a cabinet and a drum rotatably provided in the tub. The cabinet is provided with a door that allows a user to put or take the laundry in or out of the drum. A gasket is provided between the door and the tub to prevent washing water from being leaked into the washing machine. The gasket includes a bent portion of a predetermined size and damps vibration of the tub and the drum using the bent portion.
[0006] However, friction occurs between respective inner surfaces of the bent portion due to the vibration of the drum and the tub. In this case, the inner surfaces of the bent portion are abraded, and the bent portion is damaged by this abrasion. For this reason, the washing water is leaked out from the gasket and failure of the washing machine is caused.
SUMMARY OF THE INVENTION
[0007] Accordingly, the present invention is directed to a washing machine that substantially obviates one or more problems due to limitations and disadvantages of the related art.
[0008] An object of the present invention is to provide a gasket for a washing machine configured to prevent a bent portion from being abraded.
[0009] 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.
[0010] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a washing machine includes a cabinet, a tub provided in the cabinet, storing washing water, a drum rotatably provided in the tub, washing the laundry, a door provided in the cabinet, a gasket provided between the door and the tub, including a bent portion, and a reinforcement member provided in the bent portion of the gasket, preventing the bent portion from being abraded.
[0011] The reinforcement member is configured to allow facing inner surfaces of the bent portions to be spaced apart from one another at predetermined intervals so that the facing inner surfaces of the bent portion are not in contact with one another.
[0012] The reinforcement member is comprised of at least one rib formed in any one of facing inner surfaces of the bent portion. Preferably, the reinforcement member is comprised of a plurality of ribs formed in any one of facing inner surfaces of the bent portion.
[0013] Furthermore, the reinforcement member is comprised of first and second ribs respectively formed in facing inner surfaces of the bent portion. The first and second ribs are arranged to face each other. The first and second ribs may be connected with each other or may be separate members spaced apart from each other.
[0014] The bent portion is comprised of a bellows and is oriented toward the door.
[0015] In the present invention, the gasket is prevented from being abraded and damaged.
[0016] 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
[0017] 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:
[0018] FIG. 1 is a sectional view illustrating a washing machine according to the present invention;
[0019] FIG. 2 is a partial perspective view illustrating a gasket fixed to a tub in a washing machine according to the present invention;
[0020] FIG. 3 is a sectional view taken along line I-I of FIG. 2 ;
[0021] FIG. 4 is a partial sectional view illustrating a gasket of a washing machine according to the present invention;
[0022] FIG. 5 is a plane view viewed in a direction A of FIG. 4 ;
[0023] FIG. 6 is a partial sectional view illustrating a modified example of a gasket of a washing machine according to the present invention; and
[0024] FIG. 7 is a plane view viewed in a direction A of FIG. 6 .
DETAILED DESCRIPTION OF THE INVENTION
[0025] 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.
[0026] FIG. 1 is a sectional view illustrating a washing machine according to the present invention, FIG. 2 is a partial perspective view illustrating a gasket fixed to a tub in a washing machine according to the present invention, and FIG. 3 is a sectional view taken along line I-I of FIG. 2 .
[0027] As shown, a washing machine according to the present invention includes a cabinet 10 , a tub 20 supported by a damper 70 and a spring 60 in the cabinet 10 , a drum 30 rotatably provided in the tub 20 , and a driver 50 connected with the drum 30 .
[0028] The driver 50 includes a rotor 52 and a stator 51 attached to the rear of the tub 20 . A driving shaft 53 is directly connected with the rotor 52 and the drum 30 to transfer a driving force of the rotor 52 to the drum 30 . Instead of the rotor 52 and the stator 51 , the driving shaft 53 may be connected with a motor located at the lower portion using a pulley and a belt.
[0029] A controller 12 is provided at the upper portion of the cabinet 10 and controls the whole operation of the washing machine. A door 11 is provided at the front of the cabinet 10 , and a gasket 100 is provided between the door 11 and the drum 30 . The gasket 100 serves to prevent washing water from being leaked into the washing machine.
[0030] As shown in FIG. 3 , the gasket 100 includes a first end 10 , a second end 120 , and a bent portion 130 formed between the first and second ends.
[0031] The first end 110 is inserted into an opening formed in the cabinet and is engaged with the door 11 that closes the opening. The second end 120 is engaged with the tub 20 .
[0032] The bent portion 130 serves to give elasticity to the gasket 100 to damp vibration of the tub 20 and the drum 30 . Substantially, the bent portion 130 is comprised of a bellows. In more detail, the bent portion 130 is oriented toward the door 11 as shown. The bent portion 130 is forwardly extended from the body of the gasket 100 . The bent portion 130 also allows the gasket 100 to damp up and down vibration and forward and reverse vibration.
[0033] Meanwhile, as aforementioned, friction occurs between respective facing inner surfaces of the bent portion 130 due to vibration of the drum 30 and tub 20 . This could lead to abrasion of the bent portion 30 . The bent portion may be damaged by such abrasion. Accordingly, a reinforcement member 200 is provided in the bent portion 130 to prevent the bent portion from being abraded.
[0034] The reinforcement member 200 , as shown in FIG. 3 , is comprised of at least one rib 200 provided in any one of the facing inner surfaces of the bent portion 130 . The rib 200 is extended along the inner surface in a radial direction of the gasket 100 . Also, the rib 200 may be formed in a single body with the gasket 100 or may separately be attached to the inner surface of the gasket 100 . The reinforcement member, i.e., the rib 200 allows the facing inner surfaces of the bent portion to be spaced apart from one another at predetermined intervals. In this case, the facing inner surfaces are not in contact with one another. Thus, the reinforcement member 200 can prevent the bent portion 130 from being abraded and damaged by friction. Preferably, a plurality of ribs 200 are formed in any one of the facing inner surfaces of the bent portion 130 . In this case, the ribs are spaced apart from one another at predetermined intervals along a circumferential direction of the gasket 100 .
[0035] Furthermore, as shown in FIG. 4 and FIG. 6 , first and second ribs 210 and 220 may respectively be formed in facing inner surfaces 131 and 132 of the bent portion. The first and second ribs 210 and 220 are arranged to face each other. When the bent portion 130 is varied by vibration, the first and second ribs 210 and 220 are only in contact with each other. Thus, the first and second ribs 210 and 220 fully prevent the facing inner surfaces 131 and 132 from being contacted with each other, and can ensure prevention of abrasion of the bent portion 130 . Preferably, a plurality of first and second ribs may be formed in the inner surfaces 131 and 132 . In this case, as shown in FIG. 5 and FIG. 7 , the first and second ribs are spaced apart from one another at constant intervals. Also, the first and second ribs 210 and 220 , as shown in FIG. 6 and FIG. 7 , may be separate members spaced apart from each other. Alternatively, as shown in FIG. 4 and FIG. 5 , the first and second ribs 210 and 220 may be connected with each other. In other words, the reinforcement member 200 may be comprised of ribs successively extended over the facing inner surfaces of the bent portion 130 . The successive first and second ribs 210 and 220 wholly support the bent portion 130 to enhance the intensity of the bent portion 130 .
[0036] The operation of the aforementioned gasket according to the present invention will be described as follows.
[0037] First, if the power is applied to motors 51 and 52 , the drum 30 connected with the motors is rotated by the motors to perform a washing function. Vibration generated by rotation of the drum 30 is transferred to the gasket 100 through the tub 20 . The bent portion of the gasket is twisted or distorted by the vibration. At this time, the inner surfaces 131 and 132 of the bent portion are in contact with each other due to the reinforcement member 200 . Thus, the inner surfaces 131 and 132 of the bent portion 130 are not abraded. Even in case that the laundry enters the bent portion 130 , the reinforcement member 200 minimizes contact and abrasion of the inner surfaces 131 and 132 of the bent portion.
[0038] As described above, the gasket is neither abraded nor damaged by the reinforcement member. Therefore, owing to the reinforcement member, it is possible to previously avoid failure of the washing machine that may be caused by leakage of the washing water.
[0039] 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. | A washing machine including a gasket having improved durability is disclosed. The washing machine includes a cabinet, a tub provided in the cabinet, storing washing water, a drum rotatably provided in the tub, washing the laundry, a door provided in the cabinet, a gasket provided between the door and the tub, including a bent portion, and a reinforcement member provided in the bent portion of the gasket, preventing the bent portion from being abraded. | 3 |
BACKGROUND OF THE INVENTION
Centrifugal rpm regulators for injected combustion engines are known that have a governor sleeve that is rpm-dependently displaceable via centrifugal weights and can transmit its control motion via at least one intermediate lever to the fuel quantity adjustment member that controls fuel supply from the fuel pump, thereby acting on a force transfer member, supported at the regulator housing and at the same time acting indirectly upon the fuel quantity adjustment member. These elements are subjected to the force of at least one control spring and include at least one elastically sprung contact engaging the force transfer member and thereby effectively come into engagement with the governor sleeve, as well as encompassing a swing lever that transmits the spring-urged travel of the contact, respectively of the adjustment control path of the governor sleeve, whose swing axle is provided with a clearance. That facilitates control movements in opposition to the prevailing control motion during at least a portion of the spring-urged travel of the contact.
There is also known a centrifugal regulator (German OS No. 1 954 834) whose adjustment control mechanism is equipped with a swing lever which facilitates control rod movement variable with rpm level that is, the control rod (and thus the maximum fuel supply) can be varied either to provide a lesser or greater quantiy of fuel during a rise in the rpm level. This latter device has several disadvantages which stem from its construction, in particular the jointed connection of the swing lever to the intermediate lever, the butting of the swing lever against at least two detents remotely situated from each other and located on the force transfer member, and at least one of the detents is elastically deflected, all of which factors account for increased friction due to the demands of pressure and sliding forces upon the pivot and the detents occurring under the force of displacement of the governor sleeve during the swinging motion of the swing lever, thus adversely affecting control rod adjustment and detrimentally influencing the fuel adjustment control of the regulator. In addition, the higher torsional stresses conducted to the swing lever during control rod adjustment are to be considered a further disadvantage of the mechanism embodied in that known regulator, since they can lead to an undesirable control rod position adjustment.
OBJECTS AND SUMMARY OF THE INVENTION
It is the primary object of this invention to pivotally affix a swing lever to the force transfer member in such a manner that the governor member has an extremity that abuts the swing lever and the force transfer member provides a counter-acting force.
It is a further object of this invention to provide the governor sleeve with a pivot point through which it will by means of a guide lever be oscillatably attached to a free end of the force transfer member.
It is still a further object of this invention to provide the force transfer member with a spring capsule which contains plural springs, one of which acts in opposition to the governor member and the other acts in parallel therewith.
It is still another object of the invention to provide a centrifugal regulator system in which frictional forces cannot adversely affect the fuel supply adjustment processes.
It is yet a further object of the invention to alleviate the aforementioned disadvantages which are associated with known centrifugal regulators.
SUMMARY OF ADVANTAGES AND IMPROVEMENTS
The centrifugal regulator of the invention, on the one hand, possesses the advantage that the friction occurring during the adjustment of control rod position cannot influence the fuel supply process detrimentally due to the arrangement of the swing lever in parallel with, and outside of, the force flow between the governor sleeve and the fuel quantity adjustment member. Only slight forces, created by the restoring means, appear at the force juncture between the intermediate lever and the swing lever, so that from there only very slight frictional forces are conducted through the regulator.
Further advantageous improvements of the centrifugal rpm regulator are provided, namely, by an improved utilization of the governor sleeve travel via a contact component preferably contained within the regulator housing and by the favorable force transfer of the intermediate lever thereby made possible. Fine control rod direction adjustment including direction reversal in opposition to the prevailing control motion is also advantageously and precisely executable, and each point of the control rod adjustment change, to increase, hold constant, or decrease fuel supply, can be set without impairment of the other set points.
The adjustment of the regulator is substantially simplified and can be undertaken exteriorly without the external placement of its important component parts because of the elastically yielding spring contact mounted in the preset spring retainer. It is particularly advantageous that the spring retainer is inserted into the force transfer member at a point thereon axial with the governor sleeve. Virtually all rotational and torsional movements caused by the regulator control forces are advantageously isolated from the swing lever. Only a relatively few, simple components are required to control the injector rod adjustment process which facilitates the manufacture of a small, inexpensive regulator possessing high control capabilities.
The invention will be better understood as well as further objects and advantages thereof become more apparent from the ensuing detailed description of a preferred embodiment taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic representation, partly in cross section of the centrifugal rpm regulator following the invention; and
FIG. 2 is a diagram illustrating the fuel supply adjustment control curves made possible by the invention.
DESCRIPTION OF THE INVENTION
There is shown in FIG. 1 a carrier member 11, pivotally supporting the centrifugal weights 12, attached to the camshaft 10, which serves as the regulator drive shaft of a fuel injection pump, not shown, for an internal combustion engine. The arms 13 on the centrifugal weights 12 engage the contact surface 14 of a governor sleeve 15 which serves as the regulator actuator. The governor sleeve 15 is slidable at its one extremity adjacent to the contact surface 14 on a guide member 17, connected to the camshaft 10, by means of a collar 16. The guide member 17 is constructed as a cylindrical shank of the camshaft 10; alternatively it can also be a part of the drive carrier 11. The opposite extremity of the governor sleeve, designated 15a, is pivotally connected by means of a pivot bolt 18, with a guide lever 22 pivotally supported on a support bolt 21 within the regulator housing 19. The thereby formed two-point support of the governor sleeve 15 decreases the friction of the sleeve considerably.
A bolt 23 which serves as the pivot point for an intermediate lever 24, is attached to the guide lever 22 between the pivot bolt 18 and the support bolt 21. A starting spring 25 is attached at one end to the regulator housing 19 and at the other end to the intermediate lever 24 and serves simultaneously as the restoring means and as the starting spring. The starting spring 25 tends to displace a control rod 27 of the fuel injection pump, serving as the fuel control adjustment member connected to the intermediate lever 24 via link 26 in the axial direction of increased fuel supply. The link 26 and the control rod 27 are connected at a pivot point 28 toward the extremity of the intermediate lever 24 provided with the starting spring 25. The intermediate lever 24 acts upon a swing lever 31 through a contact point 29 in its extremity remote from the pivot points 23 and 28. The starting spring 25 maintains the contact point 29 of the intermediate lever 24 in the position shown in FIG. 1 in contact with a set screw 32, provided on the swing lever 31, which screw serves as the counter support for the contact point 29. This set screw 32 allows adjustment of the mutually relative positions of the intermediate lever 24 and the swing lever 31.
The swing lever 31 comprises a one-armed lever carrying the set screw 32 at its free end, and is provided with an axle 33 fixedly attached to a force transfer member 34. The force transfer member 34, comprising a one-armed support lever, is pivotally mounted on the support bolt 21 of the regulator housing 19 together with the guide lever 22 and is urged at its lower extremity 34a by a swivelable regulator spring 35 forming a tension spring against an adjustable stop screw 36 incorporated in the housing 19.
A spring retainer 37 secured by a nut 38 in an installed position serves as a yielding contact point and is screwed into the force transfer member 34 co-axially with the governor sleeve 15. The spring retainer 37 includes a contact bolt 39, a contact shell 41, and two springs 42 and 43 mounted in tandem, in addition to safety and support washers not delineated further.
Between the axle 33 and the set screw 32 which serves as the counter support for the contact point 29 of the intermediate lever 24 lies a region designated 31a at the level of the axis of the regulator sleeve 15. The region 31a of the swing lever 31 presses continuously with its one side against the contact bolt 39 of the spring retainer 37 under the force transmitted via the intermediate lever 24 from the starting spring 25, or under the force of the governor sleeve 15. On its other side, the swing lever 31 is subjected to the action of the convexed surface 44 of the governor sleeve 15, which surface 44 presses continuously against the swing lever 31, after traversing a sleeve excursion "a" which occurs at rpm levels above that of the starting rpm.
The spring retainer 37 and the swing lever 31 comprise the primary component parts of an adjustment mechanism 45 capable, as is further explained below, of effecting movement of the control rod 27 to increase fuel supply during an increase of the rpm, in spite of the concurrent movement of the governor sleeve 15 to decrease fuel supply. This contrary, opposed directional movement of the control rod 27, in opposition to the sense of the prevailing control motion is also called "negative approximation", whereby the control rod 27 of the injection pump is displaced during increased rpm's so as to direct the apportionment of an increased fuel supply. This movement in opposition to the prevailing control motion is essentially accomplished by means of the lever arm force translation of the swing lever 31, whose set screw 32, which serves as the counter support for the contact point 29 of the intermediate lever 24, executes a greater stroke during axial movement of the governor sleeve 15 than does the sleeve, so that the contact point 29 executes a longer travel than the bolt 23, which serves as the pivot point for the intermediate lever 24, and thus the intermediate lever 24 rotates about bolt 23 in a counterclockwise direction.
To terminate or to reverse the control movement of the intermediate lever 24 moving in opposition to the prevailing control motion effected by the swing lever 31, a stop 47 is provided in the form of a set screw secured in the regulator housing 19. This set screw 47 is placed in such a manner that a contact surface 48 at the lower extremity of the intermediate lever 24 having the contact point 29 just touches the set screw 47 after the contact bolt 39 has traversed a pre-set distance designated "b", whereupon its travel is limited by the shell 41 of the spring retainer 37. Thus, upon further axial movement of the governor sleeve 15 the set screw 47 acts as the momentary pivot point for the intermediate lever 24.
If the protruding dimension designated "c" of the contact bolt 39 is, as shown, greater than "b", then not only can there be movement of the control rod in opposition to the prevailing axial motion of the governor sleeve, but there can also be control rod movement toward "stop"; the former being opposed directional movement, the latter being uni-directional movement. The associated adjustment control path is then "c"-"b" and the corresponding rpm range is determined by the pre-loaded tension and the stiffness of the adjustment spring 43. When "b" and "c" are equal, then only one adjustment point is provided for motion opposing prevailing control motion and only one adjustment spring is needed (not shown). The dimension "b", determining the adjustment control path allowing opposed directional movement and the pre-loaded tension and stiffness (spring rates) of the adjustment springs 42 and 43, determining the characteristics of the adjustment process, can advantageously be pre-set at the spring retainer 37, prior to its installation into the regulator, so that only the protruding dimension "c" must be set at the regulator. The spring retainer 37 can also be adjusted, together with the support lever 34, prior to their installation, so that the protruding dimension "c" is then also preset. The positioning of the spring retainer 37, the contact screw 36, and the set screw 47 can readily be carried out externally of the regulator through an opening 51 in the regulator housing 19 upon removal of a cover 49. An auxiliary idle spring 53, retained in a screw shell 52 and acting on the support lever 34, can also be adjusted from the same side of the regulator housing.
The regulator spring 35, made pivotal to vary its force, direction and pre-tension, is hooked with one end to the support lever 34 and with its other end into a lever 54 and connected via a shaft 55 to an operating lever 56 positioned externally of the regulator housing 19. The motion of the lever 56 is delimited by a stop 57 and the pre-set stop position determines the maximum engine rpm allowed by the regulator. If the regulator spring 35 is brought to the location represented by the dash-dotted lines by rotating the levers 56 and 54 in a clockwise direction, then a correspondingly lower partial-load rpm or idle rpm is the maximum rpm attainable.
It is especially important, particularly in an emergency, that the control rod 27 can be moved in the direction of stop without excessive effort or the destruction of vital components despite the fact that the lever 56 is in the full load position, or that the other regulator components are in any other attitude not corresponding to the stopped position. Such an emergency shutdown is accomplished in the centrifugal rpm regulator of the invention by a particularly simple means, due to the force coupling between the intermediate lever 24 and the swing lever 31 created by the start spring 25 with the aid of a shutdown device which acts at least indirectly on the intermediate lever so to turn the lever 24 clockwise, thus lifting its contact point 29 off the counter support 32. Such a shutdown device of simple construction is designated 58 in FIG. 1 and contains a shutdown lever 59 which acts directly upon the intermediate lever 24. A similar shutdown device could also act directly on the control rod 27, or on that extremity of the intermediate lever 24 provided with the support point 29.
The fuel supply adjustment processes achieved by the centrifugal rpm regulator of the invention are diagrammatically plotted as a fuel supply control rod graph in FIG. 2. The abscissa represents the rpm "n", and the ordinate represents the position of the control rod R. The dashed line ABC shows the control rod travel in the lower rpm range, from a high fuel supply position for starting, where the control rod is under the influence of the start spring 25, line A-B, to a lower fuel supply level corresponding to the control rod travel to point C. The heavy line DEFG between the rpm lever n1 to n4 is designated I; this line shows the control rod adjustment path wherein the centrifugal rpm regulator according to the invention first effects a negative adjustment of control rod direction from points D to E, and then effects a contrary direction adjustment from points F to G. Between points E and F no directional adjustment of control rod movement is taking place. Alternatively, if control is desired over points E-F, then the control rod travel adjustment process can also be effected over path DEG corresponding to the line designated II. If only negative adjustment over points D to E is desired, then the rod adjustment path proceeds through points DEFH according to the line designated III. The points E and F correspond to the rpm points n2 and n3.
DESCRIPTION OF OPERATION
FIG. 1 shows all of the regulator components in rest position: the operating lever 56 butts against the stop 57, the control spring 35 is pre-loaded to effect the maximum rpm (magnitude n4 of FIG. 2), the force transfer lever 34 is pulled at its lower end 34a aganist the stop screw 36, and the control rod 27 is displaced to its starting position (designated A in FIG. 2) by means of the starting spring 25 so that the injection pump supplies the additional fuel required for starting the engine. After starting the engine, the higher fuel supply lever provided at point A remains constant up to an rpm level corresponding to point B which level is determined by the pre-tension of the starting spring 25, at which rpm level the governor sleeve 15 moves through its starting travel "a" until the surface 44 abuts the swing lever 31, which movement causes the guide lever 22 to be turned counterclockwise by pivot bolt 18 and this movement is conveyed to the bolt 23, serving as the pivot for the intermediate lever 24 which also moves to the right. The intermediate lever 24 whose contact point 29 abuts the set screw 32 of the swing lever 31, is thus rotated clockwise, so that control rod 27 is moved from the starting position to a lower fuel supply position (designated C in FIG. 2) via a rightward shift of the link 26.
Due to pre-loading on the adjustment spring 42, the control rod 27 remains in that fuel supply location designated C up to rpm level n1, corresponding to point D. Upon a rpm rise above level n1, the adjustment spring 42 recedes, allowing the contact bolt 39 to move to the right through adjustment control travel "b" until bounded by the shell 41. As the contact bolt 39 recedes into the shell 41, the swing lever 31 swings about its axle 33, and the set screw 32, serving as the counter support for the intermediate lever 24, moves through an arc proportional to the length of the lever, and thus, in accordance with the lever ratio. Throughout all these movements of other components, the intermediate lever 24 remains in continuous contact at its contact point 29 with the set screw 32 via the starting spring 25 and as hereinabove described, because the contact point 29 moves through a longer travel than the bolt 23, the intermediate lever 24 rotates counterclockwise so that the control rod 27 is displaced (from point D to point E of FIG. 2). This action effects a negative adjustment of control rod 27, and thus a correspondingly increased fuel supply during a rise of the rpm from n1 to n2.
Upon a further rise of the rpm from n2 to n3, no control rod movement takes place, because of the pre-loading on the second adjustment spring 43. As the rpm's rise above n3, the second adjustment spring 43 also recedes, and the intermediate lever 24 having before moved through the adjustment control travel "d" (corresponding to "b") with its contact surface 48 abutting set screw 47, is now rotated to effect further control rod movement, that is clockwise about the bolt 23, so that the control rod 27 is moved to the point designated G until rpm level n4 is reached. The positive adjustment travel of the control rod thus effected which causes a fuel supply reduction to take place with a rise in the rpm level, ends exactly at the governor shutdown rpm level n4. This shutdown point can also occur at a rpm level below that of n4 by an appropriate pre-loading tension of the adjustment spring 43, and the judicious adjustment of the protrusion dimension "c". In the regulator, according to the invention, the given rpm ranges and the control adjustment travel can be varied independently of one another within relatively wide limits, and thus can be tailored to the required characteristics graph of a given engine by appropriate choice of the pre-loading and spring stiffness of the adjustment springs 42 and 43 and by appropriate choice of the correspondingly set dimensions "b" and "c".
If only negative adjustment of the control rod is desired, then the dimension "c" is reduced to the same value as "b" and the set screw 47 is adjusted so that the contact surface 48 of the intermediate lever 24 just touches the set screw 47 after the lever has travelled through control path "c". If the fuel supply is desired to proceed through rpm levels n1 to n4, i.e. from D to G without a plateau between the points E and F, as shown by the line II, then the pre-loading on the second adjustment spring 43 must be set so that the spring begins to recede as soon as the lower end 34a of lever 34 has travelled through control path "b". Such control path can also be effected by use of a single spring in the spring retainer 37, with a correspondingly adjusted set screw 47; point E is then determined solely by the position of the set screw 47. However, the slope of the curve portion E-G is dependent upon the slope of the curve portion D-E, due to the fixed spring stiffness and hence the former cannot be varied at will.
When the regulator rpm's exceed the preset governor point n4, then the surface 44 of the control sleeve 15 presses upon the support lever 34, via the swing lever 31 abutted firmly against it, pushing support lever 34 away from the contact point 36, thus overcoming the pre-loaded spring force of the control spring 35 and rotating support lever 34 in a counterclockwise direction about its axis, bolt 21. Thereupon, the bolt 23 is moved to the right by the guide lever 22, and the intermediate lever 24, with its contact point 48 abutting against the set screw 47, thus executes a clockwise turning movement, pulling the control rod 27 toward the stopped position, which action is represented in FIG. 2 by the curve portion G-K.
The subject of the invention is not restricted in any way to the embodiment shown in FIG. 1, rather the component parts are changeable within the spirit of the invention. Thus, the guide lever 22 can be omitted, and the function of the bolt 23 assumed by the pivot bolt 18, with control sleeve 15 guided by other corresponding means. Alternatively, the set screw 47 can be attached to the support lever 34, if, as thus altered, the force translation then provided is sufficient for the correct functioning of the regulator. Instead of the pivotable control spring 35, a pressure spring could be provided to act on the support lever 34, and the support lever 34, serving as the force transfer member, alternatively can be constructed as a two-armed lever, or be supplanted by an appropriate receding support member with guide means in the regulator housing. | A centrifugal regulator for an internal combustion engine having a fuel injector controllable by actuation of a control rod. Movement of the governor sleeve upon a variation in rpm is transferred to a spring-biased support lever, which is pivotally connected to a guide lever by a fixed pivot thereof, which guide lever is pivotally connected to an intermediate lever by a fixed pivot thereof, which lever is provided with a pivot axis and a link connecting it with the control rod. Various types of relationship between fuel injection rate and rpm are obtained by means of several differently placed adjustable or resilient stops provided on the spring-urged support lever and in the regulator housing. These stops come into play in a multi-stage serial relationship, allowing the support lever and the intermediate lever to severally pivot and rotate, thus transferring governor sleeve movement to the intermediate lever and the control rod. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to knitting machines, for example circular knitting machines for stockings and socks, large diameter circular knitting machines, and flat bed knitting machines.
2. Description of the Prior Art
Knitting machines conventionally include needles having articulated latches. Latch needles are liable to frequent breakages which result in stoppages in production. Latch needles also cause wear of associated sinkers.
In these conventional machines, needle selection is obtained by raising and lowering the needles, and the stroke length over which the needles must be moved to provide the selection does act to limit the maximum speed attainable by the machine.
SUMMARY OF THE INVENTION
According to the invention, there is provided in a knitting machine, latchless needles each having means defining a longitudinal slot therein, hook-type selector elements slidable generally perpendicularly to the needles and movable between raised and lowered positions perpendicularly to the plane of formation of the fabric, each selector element having a hooked end portion arranged to extend into the said longitudinal slot of an associated needle, and control means selectively operative to move the selector elements generally perpendicularly to the needles and to raise and lower the selector elements so that their hooked end portions can enter the slots in the associated needles and be raised in order to take-up the stitch engaged by the needle and to remove it therefrom, and then be lowered to remove the stitch by lowering the hooked end portion under the plane of formation of the fabric.
The hook-type selector elements can comprise butts arranged to co-operate with two cam contours for providing reciprocating movement of the elements. Each selector element preferably includes single fulcrum by which the element is supported to permit reciprocatory and also pivotal movement. In addition, each element may comprise butts co-operating with the control means.
The control means may move towards the needles, those selector elements which are to take-up the stitch and remove it from the respective needle. The reciprocatory cam contours act at least on those selector elements which are moved forwardly in order to lower each selector element before penetration into the slot in the needle, and to lift it before its removal from the needle, which occurs before the needle is lowered.
The selector elements may each comprise a portion which is always at least partly inserted into the slot in the respective needle. The selector elements can additionally, or alternatively comprise lateral projections co-operating with the sides of the slots in the needles, in order to guide the selector element into the needle slots.
Preferably the selector elements and sinkers are alternately arranged in slots provided in a member--such as an outer ring of a needle cylinder--in which the slots for the sinkers are provided, the sinker control means being located on the opposite side of the member to the control means for the selector elements.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which:
FIG. 1 is a fragmentary section of a circular knitting machine in accordance with the present invention, the section being taken on line I--I of FIG. 2;
FIG. 2 is a fragmentary section taken on line II--II of FIG. 1;
FIG. 3 is a side elevation of a selector element;
FIG. 4 is a fragmentary section on line IV--IV of FIG. 3;
FIG. 5 is a section similar to that of FIG. 1, but taken on line V--V of FIG. 2;
FIGS. 6 and 7 are sections on line VI--VI and VII--VII, respectively of FIG. 5;
FIGS. 8 to 15 are fragmentary sections showing an operational sequence of the needles, selector elements and sinkers;
FIG. 16 is a section on line XVI--XVI of FIG. 1;
FIG. 17 shows schematically the relationship between the needle trajectory and the profiles of the cams for controlling the selector elements; and
FIGS. 18 to 19 are vertical and horizontal fragmentary sections of a modified embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings the reference numeral 1 indicates a needle cylinder having longitudinal grooves or tricks 3 defined by the bars 4 and slidably receiving needles 5 which are described in detail hereinafter. The reference numeral 7 indicates an inner ring of the needle cylinder 1 which is located at the top end of the needle cylinder and is provided with radial slots 7A for radial sinkers. The bars 4 reach the level of the slots 7A. The reference numeral 9 indicates an outer ring, which is fixed in conventional manner to the outside of the needle cylinder 1 adjacent to the upper end thereof, by means of clamps 10.
In the example shown, the outer ring 9 is formed with a large lower annular recess 9A. The outer ring 9 comprises radial slots 9B, which correspond to the spaces between adjacent needles 5, in order to receive sinkers 12. The slots 9B extend from the upper surface of the ring 9 and are of such a depth that they reach the recess 9A, so that the lower ends of the sinkers 12 project into the recess 9A. Each sinker comprises at least one butt 12A projecting into the recess 9A below the bottom edge of the sinker for controlling the sinker. An annular spring of conventional type, (not shown) may be provided to bias the sinkers in a radially inward direction.
In order to drive the sinkers positively at least in a radially outward direction (or also positively in both radial directions), a structure 16 surrounding the needle cylinder extends below the ring 9 and comprises an annular member 16A, which extends into the recess 9A and which either carries, or is in the form of, cams 18 and possibly 19 for acting radially on the butts 12A of the sinkers 12. The structure 16 can be fixed, or can be angularly adjustable or can be provided with pendular motion.
The reference numeral 16B indicates a further part of the structure 16 surrounding the upper part of the needle cylinder, and this structure comprises supports for rollers 20 and 22 which act to center the part 16B. From the lower surface of the part 16B there project circumferential cam profiles and movable sliding bar cams. In particular, sliding bar cams 24 for radial control are driven vertically by sheathed cables 24A in such a manner as to be moved into either an active or inactive position according to a control program. In addition, annular cam profiles operating vertically, that is parallel to the axis of the cylinder 1, and indicated by 26 and 28 can be constituted either by additional elements or can be fixed or adjustable, for the purpose indicated hereinafter.
In intermediate positions between the slots 9B for the sinkers 12 in the outer ring 9, and thus in positions corresponding with the needles 5, there are provided further radial slots 9C, each of which can receive a relatively thin hook-type selector element 30. As shown in FIG. 3, each of these selector elements 30 comprises two upper butt surfaces 30A and 30B designed to co-operate with the annular cam profiles 26 and 28, and at least one butt chosen from a series of selection butts 30C designed to co-operate with the radially acting sliding bar cams 24. The selector element 30 comprises, at its inner end facing towards the axis of the needle cylinder, a hook-like extension 30E which points upwards, a projection 30F extending in a radially inwards direction, and a lower projection 30G which can comprise lateral enlargements in the form of cheeks 30H, for alignment and guiding purposes. Along their lower edges, the selector elements 30 comprise a single point 30L acting as a fulcrum by which the selector element is supported on the base of the associated slot 9C for reciprocatory and angular movement for the purpose indicated hereinafter. Each selector element 30 moves on its point 30L both angularly and rectilinearly in its own plane, this being a plane radial to the cylinder and in which the corresponding needle is also located.
Each needle 5 has a hook 5a at its upper end portion, the hook 5a being directed vertically instead of being inclined outwards, as occurs in conventional latch needles. In addition, the needles 5 each comprise a longitudinal slot 5B analogous to that provided for receiving a latch. This slot 5B can be a through-slot. This slot 5B is arranged to receive the hook-like extension 30E and projection 30F of the selector element 30, which moves radially relative to the needle. The walls of the slot 5B can, for this purpose, be suitably shaped to provide a lead-in if the selector element 30 enters or leaves the slot 5B, but this is not necessary if the projection 30F always remains at least partly inserted in the slot 5B, even in the radially outermost position of the element 30.
The needles 5 and hook-type selector elements 30 are controlled in such a manner as to co-operate synchronously for the purpose indicated hereinafter. The needles 5 are raised and lowered--for each feed--by constant limited amounts and without any lifting selection, except for that provided at the commencement of knitting. This dispenses with the need for needle selection systems comprising selectors or jacks with several butts and control cams therefor controlled by program drums or the like. As a consequence of this, the required lift for controlling the needles is much smaller than that required in conventional machines.
In order to make the selection corresponding to the conventional selection for either removing or not removing the stitch from the needle, the selector elements 30 are operated by the movable sliding bar cams 24 for radial control, and according to whether the butts 30C are present or absent, the elements 30, preselected by the program or design, are either advanced radially inwardly or not advanced, until the hook-like extension 30E of each selector element, which has been advanced, penetrates into the needle slot 5B, the hook-like extension then being lifted and extracted radially from the slot. This is effected selectively by the selector elements 30 corresponding to the needles from which the stitches are to be removed. The cam profile 26 is formed in such a manner as to cause the hook-like extension 30E of the hook-type selector 30 to descend at the correct time to below the plane of the sinkers 12, by angular movement about the pivot point 30L, when the selector element 30 has been advanced radially inward in order to penetrate into the slot 5B of the previously raised needle 5.
The cam profile 28 imposes (and the profile 26 allows) lifting of the hook-like extension 30E after penetration into the needle slot 5B, and before and during the return of the selector element 30 in a radially outward direction. The selector element 30 is returned radially outwardly before the needle is lowered. This movement is effected with the hook-like extension 30E raised, and hence the stitch previously formed with a yarn F o is displaced by the selector element 30 outside the zone of action of the hook 5A of the needle, so that this stitch can then be taken from the needle simply by lowering the hook-like extension 30E after lowering the needle, below the sinker plane. However, if the selector element 30 has not been advanced so that its hook-like extension 30E has not been inserted into the needle slot, the stitch of the yarn F o is not removed from the trajectory of the hook 5A, and is therefore taken up and retained by the hook 5A (FIG. 15), so as to constitute a retained stitch. The selection between released stitches and retained stitches is therefore determined by a selection of the elements 30 in the sense of selecting those which are to be advanced radially inwardly in accordance with a program obtained by the operation of the cams 24 and the presence or absence of individual butts 30C in the rows of butts present on the assembly of selector elements 30.
Thus, in FIG. 8, the needle 5 is in a raised position and a yarn F o is located on the throat of the sinker 12. As shown in FIG. 9, one of the elements 30 is advanced radially inwardly into the hook-like extension 30E of the element 30 penetrates into the needle slot 5B. The hook-like extension 30E then, as shown in FIGS. 10 and 11, is respectively lifted and extracted radially from slot 5B thereby engaging the yarn F o . The selector element 30 is returned radially outwardly, with the hook-like extension 30E raised, the sinker 12 is advanced radially inwardly, and the needle 5 is lowered to a position where a new yarn is placed in the yarn engaging member, that is, the hook of the needle, as shown in FIG. 12. The hook-like extension 30E is lowered to permit taking of the stitch therefrom after the needle is lowered below the sinker plane, as shown in FIG. 13. In FIG. 14, the sinker 12 retracts and the needle 5 is returned to the raised position so that the process may be repeated.
The pivotal and rectilinear movements of the selector elements are obtained by the cam profiles 26 and 28 and cams 24, as shown in FIGS. 1 to 17. For each yarn feed, as shown in FIG. 17, the profile 28 comprises a downwardly-inclined portion 28A and a lower horizontal portion 28B corresponding to a portion of the path of the needles in which the needles 5 have already been raised and the selector elements 30 have already been advanced radially inwardly by the cam or cams 24 active at that time. It should be noted that this lowering can be effective on all the selector elements 30 irrespective of whether they are advanced. By lowering the radially outer end of a selector element 30, the profile 28 raises its hook-like extension 30E after it has penetrated into the slot 5B in the needle.
The cam profile 26 is inoperative over the portions 28A-28B of the profile 28. A lower horizontal portion 26A of the profile 26 keeps the hook-like extension 30E lowered during the radially inwards advance of the selector element 30 (path 30X in FIG. 17) by means of the active cam 24. During the action of the portions 28A, 28B, a raised horizontal portion 26B of the profile 26 is inactive. During the action of the portion 28B, the raised hook-like extension 30E is withdrawn (path 30Y), this being done by means of an outer radial contour 26Y on the cam profile 26, which acts on a butt 30M of the selector element 30. The action of the contour 26Y takes place as the needle begins to lower (path 5Y). When the action of the portion 28B ceases, the withdrawn hook-like extension 30E is lowered by inclined portion 26C of the profile 26 and the stitch hooked by the hook 30E is thereby dropped from the needle which in the meantime has also been lowered (path 5Z) below the sinker plane.
Even when the hook-like extension 30E is withdrawn, the projection 30F of the selector element remains in the slot 5B and keeps the extension 30 aligned with the needle; this can also be aided by the possible presence of the cheeks 30H, which are guided by the bars 4 of the grooves for the needles 5. The cheeks 30H could also replace the projection 30F in its guide and alignment function.
In the embodiment shown in FIGS. 18 and 19, a different selection system for the hook-type selector elements is provided. This system comprises a group of selection cams thrusting against hook-type selector elements 130. In this embodiment, in which members equivalent to those in the previously described embodiment are given the same reference numerals, there is provided a single advancing cam 114, which acts on butts 130N of those selector elements 130 which have not been lowered, the lowered selector elements 130 not being advanced. Those selector elements 130 which are not to be advanced are lowered by movable selection cams 124 which act on butts 130C which are present according to the particular pattern. The extent of lowering imposed by the cams 124 is relatively greater than that imposed by the portion 28A of the cam profile 28. The advancing cam 114 and its extension 114A ensure that the selector element is in its advanced position during the raising of the hook-like extension 30E. The other operations take place in the manner already described.
The embodiments described provide many advantages over conventional designs using a latch needle or a resilient needle.
The elimination of the latch needle eliminates the consequences of frequent breakages of the latches and needles. The needle stroke is reduced because the stitch does not now have to pass under the latch, and thus the stitch does not have to be removed from the needle by lowering it. The sinkers do not wear to the extent which occurs when latches are present. The yarn guides can be moved closer to the moving needles as these do not have an open latch (which could project at 90° to the needle with the corresponding risk of striking against the yarn guide). The yarn guide mouthpiece now serves no purpose and can be dispensed with, but if it is kept it does not have to be constructed of hard material (such as ceramic) to reduce the wear due to the rubbing of the latches. Selection is carried out by moving the hook-type selector elements, the movements being very limited both with regard to their angular extent and to their radial extent. This necessitates only limited ramp lengths on the cam profiles. For raising the needles, no selection is required.
The above arrangements permit an increase in speed, and a reduction in the space required for the control cam profiles. The needles require no selection, other than the fixed conventional selection required to commence knitting.
Compared with resilient needles, there are further advantages in the smaller needle stroke and the much more limited wear.
In a modified arrangement (not shown) selection could be carried out with an equal stroke for all the hook-type selector elements 30 or 130, and by raising only those selector elements 30 or 130 which have to remove the stitch.
Although the invention has been described with particular reference to circular knitting machines, it is equally applicable to all other types of knitting machines which conventionally operate with latch needles.
Although in the embodiment described, the needles are directed vertically the needles need not necessarily be vertical, and the terms "raised" and "lowered" and like terms as used in the appended claims are not to be construed as restricting the claims to an arrangement in which the needles are vertical. | A knitting machine includes latchless needles, and selector elements located in positions corresponding therewith. Each selector element comprises a hook-like extension directed towards the needle point and arranged to penetrate into a longitudinal slot in the needle. The selector elements are subjected to sliding movements approximately perpendicular to the needles, together with lifting and lowering movements so that they penetrate into the needle slot, and are lifted in order to take-up the stitch engaged by the needle and to remove it therefrom. Alternatively the selector element can abandon the stitch by lowering its hook-like extension below the plane of formation of the fabric. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a rotary compressor and more particularly to the type of rotary compressor having a rotating piston.
2. Description of the Prior Art
Rotary pumps and compressors of the type having a rotating piston are well known in the art and generally comprise a housing defining a cylindrical chamber having an inlet and outlet and housing a cylindrical roller or piston of lesser diameter. The rolling piston is driven in rolling contact with the inside wall of the chamber and a retractable divider member extends outwardly from the chamber wall to sealingly engage the piston between the inlet and outlet opening and divide the chamber into an inlet or low pressure side and an exhaust or high pressure side. The rolling piston is driven about the inner wall of the chamber by an eccentric crank member on the axially disposed drive shaft of the compressor. For the most part, the eccentric crank is a solid member configured to force the rolling piston into compressive engagement with the chamber wall. However, in some instances, it is conceivable that a non-compressible material, such as liquid refrigerant, would enter the compressor chamber along with vapors to be compressed therein. This liquid material, being non-compressible, is quite apt to damage the compressor.
It is known in pumps having similar rolling piston configurations as the compressor of the instant invention to have a yieldable (e.g. spring) crank arm or linkage forcing the rolling piston into compressive engagement. This permits the non-compressible material in the pumped fluid to pass through the pump without damage thereto. U.S. Pat. No. 2,460,617 discloses a pump of this nature.
Further, it is recognized that the pumping capacity of a rotary pump can be regulated by adjusting the amount of eccentricity of the roller (e.g. from its full eccentric position in rolling contact against the inner wall of the pumping chamber providing maximum pumping capacity to a position of concentricity with the drive shaft wherein the pump would have no pumping capacity). However, such mechanical linkage involves a multiplicity of parts. U.S. Pat. No. 2,266,191 shows a mechanism in a rotary pump for adjusting the pump capacity.
SUMMARY OF THE INVENTION
The present invention provides a rotary compressor having a rolling piston resiliently urged into its normal operating position in rolling contact with the compressor chamber. The resilient forces are developed by a hydraulic arrangement within the eccentric crank members to resiliently force the rolling piston against the chamber wall, however, upon encountering a non-compressible material, the force on the hydraulic arrangement is such as to permit retraction of the rolling piston so it could pass thereover. Further, by completely relieving the hydraulic pressure on the crank mechanism, the capacity of the compressor can be reduced to zero.
DESCRIPTION OF THE DRAWING
The FIGURE is a cross sectional elevational schematic view of the rotary compressor according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the FIGURE, a rotary compressor 10 is schematically shown and is seen to comprise an outer housing 12 defining an interior cylindrical chamber 14 having an interior wall 15. A compressor head 16 is disposed over an opening 18 into the chamber 14 and defines an inlet port 20, an outlet or high pressure port 22 and a sleeve 24 having a divider member 26 received for reciprocal movement therein. Divider 26 extends from the sleeve to project radially into the chamber and ride on the surface of an eccentric rotating piston 28, to be described later, and divide the inner cylindrical chamber 14 into a suction side 30 and a discharge side 32. Outlet port 22 has disposed therein a check valve 34 permitting high pressure flow outwardly of the discharge side 32 of the compressor. A plate member 36 covers the ports 20, 22 in the compressor head and defines threaded apertures 38, 40 for fittings to refrigerant tubes (not shown) to route the vaporized refrigerant through the compressor 10.
The rotating piston 28, as is well known in the art, comprises a cylindrical member 42 having a smaller diameter than the inner diameter of the cylindrical compressor chamber 14 so as to define the suction and discharge space 30, 32. Also, the axis of the cylindrical member 42 is eccentric to the axis of the chamber 14, and a drive shaft 44, concentric to the cylindrical chamber, drives the member 42 in substantially rolling contact between the inner surface 15 of the chamber and the outer surface of the member by an eccentric crank 46.
In the instant invention, the eccentric crank 46 comprises a first crank member 48 integrally attached to the drive shaft 44 and in driving engagement with an internal cylindrical surface 50 of an inner race 52 of a roller bearing 54. The outer race 56 of the bearing 54 engages the cylindrical member 42. Roller bearings 43 are interposed between the inner and outer race to provide a rolling drive between the shaft 44 and the rolling piston 28 to minimize friction. Thus, it is seen that rotation of the drive shaft 44 and crank 46 will drive the member 42 in a rolling engagement with the inner wall 15 of the cylindrical chamber 14.
As is further seen, the crank member 46 includes a second crank member 60 spatially separated from the first crank 46 with each crank member 46, 60 being substantially diametrically opposed. Crank 60 also has an arcuate face 62 in driving engagement with the inner face 50 of the inner race 52.
The first crank member 46 defines a pair of parallel cavities 64 having sidewalls substantially parallel to the direction of the diametrically opposed position of the second crank member 60 and open on the face facing the second crank member. Each cavity 64 is in fluid flow communication through passages 66 in the crank member 46, to a common fluid passage 68 in the drive shaft 44. This passage 68 is supplied fluid under pressure, such as through an oil line 70 circulating the lubricating oil from an oil reservoir 72 via an oil pump 74 which can also be driven from a power source common to the compressor 10. The pressure in line 70 can be varied as through a pressure regulating valve 71.
The second crank member 60 has a pair of integral finger-like parallel projections 78 extending therefrom and so sized and placed for each to be received within a respective opposing cavity 64 in the first crank member 46 and in generally close relationship therewith so as to act like hydraulic pistons under the influence of the fluid pressure within the cavities 46. Thus, under these conditions, the fluid pressure on the faces 80 of the projections 78 forces the second crank 60 into engagement with the face 50 of the inner race 52 which in turn forces the rolling piston 28 into rolling engagement with the inner face 15 of the cylindrical chamber 14. However, if any non-compressible material, such as liquid refrigerant, is returned to the suction side 30 of the compressor chamber 14, the force on the rolling piston 28 by such non-compressible material will exceed (by design) the hydraulic force on the second crank member 60 by the hydraulic pressure such that the pistons 78 will be permitted to slide into the cavities 64 in the first crank member 48 permitting the rolling piston 28 to roll over the non-compressible material without damage. To accommodate the necessary discharge of oil from the cavities 64 under such conditions without backflow through the pump 74, a pressure relief valve 82 is placed on an oil line 84 downstream thereof in communication with an oil return line 86 to the oil reservoir 72. It must be emphasized that the pressure on the pistons 78 must establish a sufficient force to maintain intimate rolling contact between the rolling piston 28 and the inner face 15 of the cylinder during the complete travel of the rolling piston. However, it is also apparent that by eliminating oil flow to the cavities 64, as through a bypass of the oil flow to the cavities, there is insufficent pressure on the hydraulic piston 28 to maintain the intimate rolling contact and, in effect, the rolling piston will continue to be driven by the drive shaft 44, however, there will be no compression of fluid within the compressor chamber 14.
It should be herein pointed out that for the rolling piston 28 to roll over a non-compressible material, the inner race 52 will become lifted from the arcuate face of the first crank 48. Thus, to accommodate this, the arcuate dimension of the first crank 48 must be less than 180° (i.e. it cannot extend across the diameter of the inner race 52) to permit such relative movement between the race 52 and the first crank member 48. Under such conditions, the torque to the rolling piston 28 is delivered by the second crank 60 through the hydraulic pistons or projections 78.
Also shown in the preferred embodiment is a second oil pressure line 88 directing oil to the sleeve 24 to maintain a force on the divider 26 slidingly housed therein to maintain it in intimate sealing contact with the surface of the rolling piston 28. However, it is also known that a spring or the high pressure refrigerant discharge from the compressor can also be used in this sleeve to maintain such sealing force.
Thus, in a rolling piston rotary compressor, there is shown a means for hydraulically maintaining the rolling piston in compressive rolling contact with the internal cylindrical chamber to provide the desired compression of the fluid in the compressor chamber and also permitting unloading of the compressor while it continues to rotate. It is axiomatic that by varying the hydraulic pressure to the pistons, the discharge pressure of the compressor can be altered. | A rotary compressor 10 of the rolling piston type is shown wherein the rolling cylindrical piston 28 is forced into rolling contact with the cylindrical interior 15 of the compressor chamber by a hydraulic piston 78 and cylinder 64 arrangement providing a resilient force on the rolling piston 28 to permit non-compressible matter such as liquid refrigerant to be present in the compressor chamber and also, through means 82 for varying the hydraulic pressure to the hydraulic piston and cylinder arrangement, permit varying the compressor discharge pressure while the rolling piston is continuously driven. | 5 |
BACKGROUND AND SUMMARY
The present disclosure relates to a separator having a vertical axis of rotation and a drum with solids discharge openings in a single-cone or double-cone centrifugal space. The separator also includes a disk stack of super-imposed conical disks. The discs have bores forming at least one channel in the disk stack. The separator includes a distributor having a shaft concentrically surrounding a drum axis and a lower base section which expands radially. In the lower base section, one or more distributor channels are distributed in the form of bores.
It has been known for a long time to arrange disc stacks consisting of a plurality of discs situated axially above one another in the direction of the disc axis concentrically to the machine or drum axis in centrifugal drums of separators. This is known from the field of separators with drums with a vertical axis of rotation and solids discharge openings in a pulp space outside the disc stack.
In the case of separators with a vertical axis of rotation, a feeding of the product into the centrifugal drum takes place along the drum axis through a feeding pipe and radial distributor channels connected behind the feeding pipe. The product enters the centrifugal drum into the disc stack consisting of separating discs which are generally situated closely above one another but are nevertheless spaced relative to one another in the area of the essential disc surfaces and, as a rule, are conical. At the discs, heavier solids generally accumulate on the bottom side and move to the outer circumference of the disc stack, while the liquid flows toward the interior, in, for example, a two-phase liquid-solid separation.
For the implementation of a liquid-liquid-solid separation, that is, a three phase liquid-solid separation, it is also known to provide the disc stack with so-called rising channels, which are formed of bores in the discs of the disc stack situated directly or with a twist (see German Patent Document DE 100 55 398 A1) above one another.
From U.S. Patent Document US 993,791, a chamber centrifuge is known which has no solids discharge openings and in which the diameter of the bores changes within a disc stack. Or, the orientation of the openings is changed from one disc to the next in that a disc holding contour sloped toward the axis of rotation is arranged, for example, at the shaft.
The discharge of the liquids generally takes place in areas radially on the inside or radially on the outside with respect to the discs of the disc stack. It is also known to construct discharge channels for the liquid phase(s) by means of bores particularly close to the inner circumference as well as close to the outer circumference of the disc stack in the disc stack (see, for example, German Patent Document DE 284640).
It is also known to equip the discs with so-called spacers in the manner of webs and/or small tips or points which, on the one hand, provide a mutual spacing of the discs and, on the other hand, influence the flow conditions in the disc stack. Spacers can be placed between the discs which preferably are separate from the discs. The discs are generally held in grooves on a distributor shaft or in other disc holders.
The present disclosure relates to optimizing the flow conditions in the drum of a separator by simple constructive devices.
The present disclosure further relates to a separator having a vertical axis of rotation and a drum with solids discharge openings in a single-cone or double-cone centrifugal space. The separator also includes a disk stack of super-imposed conical disks. The discs have bores forming at least one channel in the disk stack. The separator includes a distributor having a shaft concentrically surrounding a drum axis and a lower base section which expands radially. In the lower base section, one or more distributor channels are distributed in the form of bores. A diameter of the at least one channel inside the disc stack, located above the disc which is the lowest in a flow direction, is not constant and/or is arranged to be sloped with respect to an axis of rotation of the drum. The bores of the at least one distributor channel are not radially oriented with respect to the drum axis in the drum.
Illustrative embodiments are described herein.
As noted above, a diameter of the at least one channel, within the disc stack above the lowermost disc in a flow direction, is not constant and/or the at least one channel is arranged in a sloped manner with respect to the axis of the drum. The bores of the at least one distributor channel do not have a radial orientation to the drum axis in the drum.
According to the present disclosure, it becomes possible, for example, in the case of a centrifuge with a pulp space outside the disc stack, with a piston valve arrangement or solids discharge nozzles to optimize the flow conditions in the drum. Further, according to the present disclosure, a combination of one or more of the above-noted features, that is distributor and channel geometry and/or channel orientation, may be utilized for optimizing the flow conditions in the centrifuge in a constructively simple manner and to optimally adapt them to the product to be processed.
It is noted that German Patent Document DE 38 80 19 shows a centrifuge of a different type with an inlet pipe which is not concentrically arranged.
A geometry of the bores of the discs of the at least one channel, which may be a rising channel, varies in the channel in such a manner that, during the operation, gaps between the discs are uniformly charged with liquid over the entire height of the disc stack. As a result of this advantageous measure, the flow conditions in the centrifuge are clearly optimized. Thus, not only a simple widening of the bores “from one disc to the next” is implemented but a flow-dependent optimization, in the case of which the bores can be designed to be constant over several discs and will then, for example, widen. In this manner, each disc separately can have an optimal design. On the production side, this can be easily implemented by laser cutting the bores in the metal sheet of the discs.
For example, the diameter of the channel can change in steps at a distance of several discs or continuously from one disc to the next and decrease in the flow direction. It is expedient for the diameter to decrease, for example, continuously, in the flow direction.
The bores may have an arbitrary shape. An optimal shape is determined by a person skilled in the art by tests as a function of the product. Thus, the bores may have a polygonal or round or curved shape in any alignment.
In an illustrative embodiment, each channel includes several bores which, in turn, advantageously may also form a perforated pattern for example, distributed on the circumference on a circle or an ellipse in the discs.
It is within the scope of the present disclosure that the at least one channel, which may be sloped, extends in a curved manner with respect to the drum axis in the disc stack.
In such an embodiment, the at least one channel may comprise a rising channel for feeding the product into the disc stack and/or, at least one discharge channel for discharging the liquid phase from the disc stack. The optimized design of rising and discharge channels also contributes to improving the flow conditions.
One of the discharge channels for discharging various liquid phases is constructed close to the inner circumference or close to the outer circumference of the disc stack and/or is constructed inside the disc stack. The flow direction extends in the direction of the liquid discharges of the drum, with the vertical orientation generally in the upward direction.
Based upon the present disclosure, it becomes possible to optimize the further development of the channels of a separator with a vertical axis of rotation as a function of the product and the machine in order to improve the parallel connection of the discs of the disc stack and to optimize the flow conditions. That is done in order to, for example, compensate separating zone displacements because of pressure differences in the disc stack, for example a radial position and to reduce instabilities in the disc stack, for example, in the circumferential direction.
The present disclosure also includes providing a distributor with at least one distributor channel constructed as a bore in a distributor base. Such a distributor channel is not oriented radially in the drum, which, in turn, optimizes the flow conditions in a simple manner as a function of the product.
According to the present disclosure, the distributor channels may be oriented in a sloped manner against the rotating direction of the drum or under certain circumstances in the rotating direction of the drum.
The distributor channels, which are formed by bores relative to the radial line through the drum axis in a radially interior bore section against the rotating direction of the drum, advantageously may be oriented to be sloped in a lagging manner.
As a result of that orientation, the flow conditions are further optimized in combination with the measure that the distributor channels lead in a further bore section into the drum, which bore section is oriented upwards in the drum and leads out directly below a rising channel of the disc stack into the drum. In addition, a more careful acceleration and an optimal entry of the centrifugal material into the rising channels is ensured.
The distributor channels may have an expanding round or a slot-type outlet which extends tangentially in or against the rotating direction of the drum and/or is directed upward in the drum.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a partial area of a known disc for disc-type centrifuges having a vertical axis of rotation.
FIGS. 2 to 8 are top views of a partial area of embodiments of different discs for disc-type separators or centrifuges having a vertical axis of rotation, according to the present disclosure.
FIG. 9 is a sectional view of a separator having two distributor channels, according to the present disclosure.
FIG. 10 is a top view of a distributor for the separator of FIG. 7 .
DETAILED DESCRIPTION
FIG. 1 shows a top view of a partial area of a known disc 1 of a disc stack for a separator.
According to FIG. 1 , the discs 1 each have a disc bore 2 . The bores 2 or holes of the discs 1 , in cooperation with several discs 1 arranged above one another, form a rising channel 3 which is situated radially in an area of a separating zone T between a lighter and a heavier liquid phase. In an area 4 , a discharge of a light liquid phase takes place radially on an inside with respect to the discs 1 , and a discharge of a heavier liquid phase takes place in an area 5 radially outside the disc 1 . Solids exit a disc stack 26 toward an outside (not shown) and can be discharged there in a known manner, for example, through nozzles or a piston valve arrangement from a centrifugal drum.
The disc stack 26 or the individual discs 1 are pushed onto a distributor shaft 16 which includes, on its outer circumference, a plurality of webs 17 directed radially from the shaft 16 to an outside, which webs 17 protrude beyond an inner circumference I of the discs 1 and thereby non-rotatably secure the discs 1 on the distributor shaft 16 relative to the shaft 16 .
As a radial extension of the webs 17 , radially directed spacers or lugs 18 are arranged between the discs 1 , which spacers 18 divide the discs 1 completely into segments 19 with an opening angle α, in which one bisecting line W is situated.
The area 4 for discharging the light phase is formed by grooves 20 in the outer circumference of the distributor shaft 16 between the webs 17 , which grooves 20 are placed symmetrically with respect to the bisecting lines W in the distributor shaft 16 .
According to FIG. 2 , the rising channel 3 has a cross-section which is not constant. That is, a diameter of the bores 2 of the discs 1 of the disc stack 26 , which form the rising channel 3 , is not constant. The diameter changes over an entire height of the disc stack 26 and it is reduced continuously along the entire height of the disc stack 26 in a flow direction F (see FIG. 9 ).
It is noted that it is known from British Patent Document GB 264,777 to provide the lowermost disc with a different hole or bore arrangement than the upper discs in order to cover a portion of the discs and be able to thereby radially displace the rising channel by exchanging the lowermost disc.
The diameter of the bore 2 , as shown in FIG. 2 , for a drum with a vertical axis of rotation, continuously decreases in an upward direction (indicated by a broken line), so that the diameter of the rising channel 3 is also reduced in the upward direction.
In addition, the rising channel 3 , as shown in FIG. 2 , is not situated parallel to a drum axis M which is perpendicular to a plane of the figure. As a result, the bores 2 of discs 1 situated above one another are no longer aligned completely but only in sections, so that the rising channel 3 may, for example, extend in the upward direction radially from the outside farther toward the inside and/or in or against a rotating direction in a circumferential direction and may therefore have a twist.
According to FIG. 2 , the groove 20 in the distributor shaft 16 for forming a discharge channel or discharge area 4 is not symmetrically aligned with respect to the bisecting line W of each disc segment 19 but is asymmetrically laterally offset. This can also optimize the flow conditions in the disc stack 26 .
According to FIGS. 3 to 5 , discharge channels 6 , 7 are constructed directly in the disc stack 26 . That is, a first discharge channel 6 for a light liquid phase is constructed radially outside the inner circumference I of the discs 1 in the disc stack 26 , and a second discharge channel 7 for a heavier liquid phase is constructed radially inside the outer circumference A of the discs 1 . These channels 6 , 7 also may be aligned not only symmetrically but also asymmetrically with respect to the bisecting line W of each disc segment 19 . This also applies to the rising channels 3 for the product feed.
The discharge channels 6 , 7 are formed analogously to the rising channels 3 by bores 8 , 9 in the discs 1 situated above one another, which bores 8 , 9 are situated close to the inner I or outer A circumference of the discs 1 . The discharge channels 6 , 7 may again have a diameter which is not constant and/or may not be situated directly above one another but offset with respect to one another relative to a drum axis M. To this extent, all of the arrangements of the bores 2 for the rising channels 3 mentioned above or below can be analogously utilized also when further developing the bores 8 , 9 for the discharge channels 6 , 7 .
According to FIG. 3 , the bores 8 of the inner discharge channel 6 for the light liquid phase and/or the bores 9 of the discharge channel 7 for the heavier phase and/or the bores 2 of the rising channel 3 may include several bores 2 , 8 , 9 in a manner of a multiple perforation 10 . In this case, individual bores can be arranged, for example, in a circle 12 , in a radially oriented straight line or in a curve oriented in the circumferential direction or a straight line 13 . The curves or straight lines may be arbitrarily oriented in an angular and/or offset manner with respect to the bisecting line W of the segment 19 or to other radial lines through the drum axis M of the centrifuge depending on the application.
According to the present disclosure, a division of the product flow into many small channels represents an improvement with respect to the uniform charging of the disc stack 26 s and optimizes the flow conditions in the disc stack 26 .
The individual bores 2 , 8 , 9 may have any geometry. Thus, a circular shape or a polygonal shape, for example, a triangular or square shape, as shown in FIG. 4 or a curved shape, as shown in FIG. 5 . The polygon or the other geometrical shapes can be oriented at any angle with respect to the bisecting line W of the angle.
It is advantageous to mutually adapt the geometry of the bores 2 , 8 , 9 of a rising channel 3 such that gaps between the discs 1 are uniformly charged with liquid over the entire height of the disc stack 26 or the rising channel 3 . This can be achieved by tests and/or theoretical considerations, such as computer simulations.
FIGS. 6 to 8 illustrate that, by an optimized development of the distributor, it becomes possible to further optimize the flow conditions in the drum 21 (see FIG. 9 ) as well as in the disc stack 26 .
A one-piece distributor 22 (see FIG. 10 ) is provided with distributor channels 14 which are not radially oriented. The channels 14 are constructed as a bore (see FIG. 9 ) and, first extend in a first bore section in the drum 21 in a sloped manner from an inside to an outside in a downward direction and end in a bore section which is constructed as an expanding or geometrically changing distributor outlet 15 a . This distributor outlet 15 a is directed upward in the drum 21 and leads directly below one of the rising channels 3 . Its outlet area may have a circular or, for example, slot-type shape. Slot-type distributor outlets 15 b (see FIG. 7 ) from the bores of the distributor channels 14 may then, in turn, extend relative to a remaining distributor channel tangentially to radial line R in the rotating direction r of drum 22 ( FIG. 7 ) or against ( FIG. 8 ) the rotating direction r of the drum 22 , or may advance or lag.
It thus becomes possible to optimize the flowing of product into the drum 22 as well as into the disc stack 26 in a very targeted manner while a feeding bore cross-section is optimized. This is in order to achieve an improved separation of particles and, if required, improve a parallel connection of the discs 1 .
FIG. 9 is a cross-sectional view of a schematically illustrated self-discharging separator having a drum 21 with a vertical axis of rotation D, which has a distributor 22 . A feeding pipe, which is not shown, leads from above into the distributor 22 . The distributor 22 has the upper distributor shaft 16 , which is oriented concentrically with respect to the axis of rotation D. The distributor 22 includes distributor channels 14 which are constructed as bores and each lead into one of the distributor outlets 15 (as shown in FIG. 9 ) or 15 a,b,c (as shown in FIG. 10 ). A piston valve 23 is used for the opening and closing of solids discharge openings 24 . The liquid discharge from the drum 24 takes place by grippers or centripetal pumps (not shown).
FIG. 10 is a top view of the distributor 22 with the distributor shaft 16 and the lower, radially expanding, almost disc-type base section 25 . Section 25 is penetrated by, for example, three distributor channels 14 , shown here by broken lines, and leading into the distributor outlets 15 a,b,c.
Straight bores, which form the distributor channels 14 in the one-piece distributor 22 , are not arranged radially but relative to the radial line R through the drum axis M (congruent with the axis of rotation D) in a lagging manner with respect to the rotating direction r, which permits a careful inflow of the centrifugal material.
The holes of the rising channel 14 are designed not to be constant over the height of the disc stack 26 . The holes are designed in an optimized manner with respect to the flow conditions to not be constant, that is, to be variable. An angle β between the distributor channels 14 and the radial line R, which extends through a starting area of the distributor channel 14 at an inner circumference of the distributor 22 , amounts to between 15 and 85°, particularly between 25° and 65°, in order to achieve a careful inflow of the centrifugal material into the drum 21 .
The distributor outlets 15 a,b,c may have various geometries which are also adapted to the rising channels 3 and which may be oriented to be lagging 15 b , advancing 15 c or “neutral” 15 a relative to a lagging distributor arm (see also FIG. 10 ).
Although the present disclosure has been described and illustrated in detail, it is to be clearly understood that this is done by way of illustration and example only and is not to be taken by way of limitation. The scope of the present disclosure is to be limited only by the terms of the appended claims. | A separator including a vertical axis of rotation, a drum having solids discharge openings and a conical centrifugal space, and a disc stack located in the conical centrifugal space. Also included is a plurality of conical discs super-imposed on one another and having disc bores forming at least one rising channel in the disc stack. Further included is a drum, a distributor and a lower base section which expands radially, and on which lower base section are one or more distributor channels. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to Chinese Patent Application No. 201610757136.6 filed on Aug. 30, 2016, and is a continuation-in-part of and claims priority to U.S. patent application Ser. No. 14/415,037 filed on Jan. 15, 2015, which in turn is a national stage application of, and claims priority to, PCT/CN2013/075684 filed on May 16, 2013, which claims priority to Chinese Patent Application No. 201310072627.3 filed on Mar. 7, 2013. The disclosures of these applications are hereby incorporated by reference in their entirety.
BACKGROUND
[0002] In recent years, many studies have been made on plant cultivation via artificial light source. In particular, the plant cultivation by the light-emitting diode (LED) attracts much attention due to excellent monochromaticity, energy saving, long service life and small size.
[0003] Plant illumination mainly includes the plant growth light and aquarium light. The plant growth light supplements the light source when the natural light is insufficient, which complements the sunlight and adjusts the agricultural product growth. The aquarium light not only improves the growth of aquatic plants, but also has the lighting effect for sightseeing.
[0004] Compared with traditional plant illumination, the LED plant illumination is advantageous in the following aspects: i) energy saving. The LED plant illumination may directly generate the light for plant with same-lumen photon, which consumes little power; ii) high efficiency. As monochromatic light, the LED can generate light waves matching the plant requirement, which cannot be achieved by traditional plant light; iii) the LED plant illumination has rich wavelength types capable of controlling the plant flowering, fruiting, plant height and nutrient contents. With the further improvement of LED plant illumination technology, it will be used for multi-layer 3D combined cultivation systems with less system heat, small space and low thermal load.
SUMMARY
[0005] The present disclosure describes an LED for plant illumination, including a new light-emitting material Ga X In (1-X) As Y P (1-Y) of which can significantly improve the light-emitting efficiency by 50%-100%.
[0006] An LED for plant illumination, comprising a substrate arranged at the PN junction light-emitting part of the substrate. The light-emitting part has a strained light-emitting layer with component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<1).
[0007] In some embodiments, the light-emitting part has a strained light-emitting layer with component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<0.2).
[0008] In some embodiments, the light-emitting part has a strained light-emitting layer with component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<0.1).
[0009] In some embodiments, the light-emitting part has a strained light-emitting layer with component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<0.05).
[0010] In some embodiments, the light-emitting part has a barrier layer, forming a 2˜40-pair alternating-layer structure with the strained light-emitting layer.
[0011] In some embodiments, each alternating-layer structure is 5-100 nm thick.
[0012] In some embodiments, the barrier layer has a component formula of (Al A Ga 1-A ) B In (1-B) P (0.3≦A≦1 and 0<B<1).
[0013] In some embodiments, the substrate material may be GaAs, GaP or any one of their combinations.
[0014] In some embodiments, the invention also comprises a buffer layer between the substrate and the light-emitting part.
[0015] In some embodiments, the invention also comprises a window layer arranged on the light-emitting part.
[0016] In some embodiments, the window layer material is GaP.
[0017] In some embodiments, the window layer is 0.5-15 μm thick.
[0018] In some embodiments, in the LED for improving photosynthesis during plant cultivation, the peak light-emitting wavelength of the strained light-emitting layer is 650 nm-750 nm.
[0019] In some embodiments, in the LED for improving photosynthesis during plant cultivation, the peak light-emitting wavelength of the strained light-emitting layer is 700 nm-750 nm.
[0020] In another aspect, an LED is provided for plant illumination, including a light-emitting part of strained light-emitting layer on the substrate with component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<1). The strained light-emitting layer material is GaInAsP, which can improve the light-emitting efficiency of the strained light-emitting layer. In addition, the material is helpful for improving life stability due to the lack of Al component.
[0021] In addition, by adjusting the composition and thickness of the strained light-emitting layer, the light-emitting wavelength from the strained light-emitting layer is in a range of 650 nm-750 nm. In some embodiments, a window layer is provided at the light-emitting part of the LED for plant illumination, which is transparent to the light-emitting wavelength, and therefore will not absorb the light from the light-emitting part. In addition, it can have a current spreading function.
[0022] Hence, according to some embodiments of this disclosure, a high output power and/or highly efficient LED capable of generating a large quantity of light-emitting wavelength of 650 nm-750 nm is provided.
[0023] In another aspect, an epitaxial wafer for a plant lighting LED is provided, including from up to bottom: a growth substrate, a first red-light epitaxial laminated layer, a DBR semiconductor laminated layer and a second red-light epitaxial laminated layer, wherein, the first red-light epitaxial laminated layer comprises a first N-type ohmic contact layer, a first N-type covering layer, a first light-emitting layer, a first P-type covering layer and a first P-type ohmic contact layer; and the second red-light epitaxial laminated layer comprises a second N-type ohmic contact layer, a second N-type covering layer, a second light-emitting layer, a second P-type covering layer and a second P-type ohmic contact layer.
[0024] In some embodiments, a doping concentration of the DBR semiconductor laminated layer is ≦5×10 17 , to form a high resistance interface.
[0025] In some embodiments, light emitting wavelength of the first light-emitting layer is 710 nm˜750 nm, and that of the second light-emitting layer is 640 nm˜680 nm.
[0026] In some embodiments, light emitting wavelength of the first light-emitting layer is 730 nm, and that of the second light-emitting layer is 660 nm.
[0027] In some embodiments, an etching stop layer is provided between the DBR semiconductor laminated layer and the second red-light epitaxial laminated layer.
[0028] In another aspect, an LED chip for a plant lighting LED is provided, including from up to bottom: a first red-light epitaxial laminated layer, a DBR semiconductor laminated layer, a second red-light epitaxial laminated layer and a conductive bonding substrate; in which, the first red-light epitaxial laminated layer comprises a first N-type ohmic contact layer, a first N-type covering layer, a first light-emitting layer, a first P-type covering layer and a first P-type ohmic contact layer; and the second red-light epitaxial laminated layer comprises a second N-type ohmic contact layer, a second N-type covering layer, a second light-emitting layer, a second P-type covering layer and a second P-type ohmic contact layer; wherein, light-emitting area of the first red-light epitaxial laminated layer is less than that of the second red-light epitaxial laminated layer; the first N-type ohmic contact layer is provided with a first electrode; between the first P-type ohmic contact layer and the second N-type ohmic contact layer is provided with an electronic-connected structure, and the second P-type ohmic contact layer is provided with a second electrode.
[0029] In some embodiments, light emitting wavelength of the first light-emitting layer is 710 nm˜750 nm, and that of the second light-emitting layer is 640˜680 nm.
[0030] In some embodiments, doping concentration of the DBR semiconductor laminated layer is ≦5×10 17 , to form a high resistance interface.
[0031] In some embodiments, surface of the second red-light epitaxial laminated layer is preset with a light-emitting zone and a non-light-emitting zone, and a DBR semiconductor laminated layer is formed on the non-light-emitting zone of the second red-light epitaxial laminated layer.
[0032] In some embodiments, area of the DBR semiconductor laminated layer is less than the light-emitting area of the second red-light epitaxial laminated layer, but larger than that of the first red-light epitaxial laminated layer.
[0033] In some embodiments, the non-light-emitting zone on the surface of the second N-type ohmic contact layer is provided with an electric diffusion structure.
[0034] In some embodiments, an etching stop layer is provided between the DBR semiconductor laminated layer and the second red-light epitaxial laminated layer.
[0035] In another aspect, a light-emitting system is provided for plant lighting. The system can include a plurality of the LED chips described above. The LED chips can form an array over a packaging frame.
[0036] In another aspect, a fabrication method for growing a plant lighting LED chip is provided, including: 1) epitaxial growth: provide a growth substrate, and form any of aforesaid LED epitaxial wafer for plant lighting; 2) substrate transfer: bond a conductive bonding substrate on the epitaxial wafer surface and remove the growth substrate to expose the first N-type ohmic contact layer surface of the epitaxial wafer; 3) defining of light-emitting zone: define a first light-emitting zone and a second light-emitting zone on the epitaxial wafer surface, and remove the first N-type ohmic contact layer, the first N-type covering layer, the first light-emitting layer and the first P-type covering layer of the second light-emitting zone to expose the first P-type ohmic contact layer; 4) electrode fabrication: remove the DBR semiconductor laminated layer of the second light-emitting zone and expose the surface of the second N-type ohmic contact layer; fabricate an N-type electrode on the surface of the first N-type ohmic contact layer, and fabricate an electronic-connected structure; electrically connect the first P-type ohmic contact layer and the second N-type ohmic contact layer.
[0037] In some embodiments, in step 3), the epitaxial wafer surface is also defined with an isolation zone between the first light-emitting zone and the second light-emitting zone.
[0038] In some embodiments, in step 3), remove the second light-emitting zone and the first N-type ohmic contact layer, the first N-type covering layer, the first light-emitting layer and the first P-type covering layer of the isolation zone.
[0039] In some embodiments, after step 4), the DBR layer is larger than the first light-emitting zone but smaller than the second light-emitting zone.
[0040] Other features and advantages of the present disclosure will be described in detail in the following specification, and moreover, will become obvious partially through the Specification or understood through implementations of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, together with the embodiments, are therefore to be considered in all respects as illustrative and not restrictive. In addition, the drawings are merely illustrative, which are not drawn to scale.
[0042] FIG. 1 is a sectional structure diagram of an LED for plant illumination according to some embodiments.
[0043] FIG. 2 is a side sectional view of a LED chip for plant lighting in accordance with Embodiment 7.
[0044] FIG. 3 is a top view of the LED chip as shown in FIG. 2 .
[0045] FIG. 4 illustrates a first step of fabricating an LED chip for plant lighting according to some embodiments.
[0046] FIG. 5 illustrates a second step of fabricating an LED chip for plant lighting according to some embodiments.
[0047] FIG. 6 illustrates a third step of fabricating an LED chip for plant lighting according to some embodiments.
[0048] FIG. 7 illustrates a fourth step of fabricating an LED chip for plant lighting according to some embodiments.
[0049] FIG. 8 illustrates a fifth step of fabricating an LED chip for plant lighting according to some embodiments.
[0050] FIG. 9 illustrates a sixth step of fabricating an LED chip for plant lighting according to some embodiments.
[0051] FIG. 10 illustrates a seventh step of fabricating an LED chip for plant lighting according to some embodiments.
[0052] FIG. 11 illustrates an eight step of fabricating an LED chip for plant lighting according to some embodiments.
[0053] FIG. 12 illustrates a ninth step of fabricating an LED chip for plant lighting according to some embodiments.
[0054] FIG. 13 illustrates a tenth step of fabricating an LED chip for plant lighting according to some embodiments.
[0055] In the drawings:
200 : growth substrate; 210 : far red-light epitaxial laminated layer; 211 : first N-type etching stop layer; 212 : first N-type ohmic contact layer; 213 : first N-type electrode diffusion layer; 214 : first N-type covering layer; 215 : first light-emitting layer; 216 : first P-type covering layer; 217 : first P-type ohmic contact layer; 220 : DBR semiconductor laminated layer; 230 : super red-light epitaxial laminated layer; 231 : second N-type etching stop layer; 232 : second N-type ohmic contact layer, 233 : second N-type electrode diffusion layer; 234 : second N-type covering layer; 235 : second light-emitting layer; 236 : second P-type covering layer; 237 : P-type transition layer; 238 : second P-type ohmic contact layer; 240 : mirror structure; 250 : conductive bonding layer; 260 : conductive bonding substrate; 271 : N-type electrode; 272 : BeAu metal layer; 273 : electronic-connected structure; 274 : electrode extension bar; 275 : P-type electrode.
DETAILED DESCRIPTION
[0057] Based on study results so far, the light-emitting wavelength of light sources suitable for plant growth is near 450 nm (blue light) and 600-750 nm (red light).
[0058] The traditional light-emitting layer for plant illumination is AlGaAsP or AlGaAs. However, the LED with light-emitting layer made of AlGaAsP or AlGaAs has low light-emitting output power. To promote feasible light source of LED for plant cultivation, it is necessary to develop LED with high output power and/or high efficiency in consideration of energy and cost saving.
[0059] The following embodiments provide a LED with 650-750 nm wavelength suitable for plant illumination, featured by high output power and stable service life.
[0060] The GaInP light-emitting wavelength is near 640 nm and the GaAs light-emitting wavelength is near 850 nm. In the following embodiments, the light-emitting layer GaInP material is doped with As and the thickness and strain capacity of the strained light-emitting layer are adjusted; therefore, an LED composed of new epitaxial structure for plant illumination is developed that is suitable for wavelength of 650-750 nm.
[0061] Detailed descriptions will be given below about this disclosure with reference to accompanying drawings and embodiments.
Embodiment 1
[0062] As shown in FIG. 1 , an LED comprises: a substrate 11 , divided into a first surface and a second surface; a light-emitting part, which consists of a stack of semiconductor material layers, including a buffer layer 12 , a first restriction layer 13 , a light-emitting layer 14 and a second restriction layer 15 , sequentially from down up and formed on the first surface of the substrate 11 ; a window layer 16 formed on a partial region of the second restriction layer 15 of the light-emitting part; a second electrode 17 , formed on the window layer 16 ; and a second electrode 18 , formed on the second surface of the substrate 11 .
[0063] In the element, the substrate 11 material may be GaAs, GaP or any one of their combinations.
[0064] The buffer layer 12 can mitigate lattice imperfection of the epitaxially growing substrate but is not a necessary film for the element.
[0065] The light-emitting part consists of an alternating layer (of strained light-emitting layer and barrier layer) structure, including at least two 2 pairs (preferably 2-40 pairs). The structure of each pair of alternating-layers is, without limitation to, 5-100 nm thick. A structure of a plurality of alternating layers can effectively improve the saturation current of the element. In this embodiment, the pair number of the alternating layer structure of alternating strained light-emitting layer and barrier layer is 6. The structure of each pair is 40 nm thick and the total thickness is 240 nm.
[0066] The strained light-emitting layer material is Al-free GaInAsP with component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<1). In some embodiments, to better control the peak wave of the light-emitting layer within 650 nm-750 nm, the Y value is preferably 0<Y<0.2. In this embodiment, X=0.5 and Y=0.01.
[0067] The barrier layer material is AlGaInP with component formula of (Al A Ga 1-A ) B In (1-B) P (0.3≦A≦1 and 0<B<1). In this embodiment, A=0.5 and B=0.5.
[0068] The window layer is GaP (thickness: 0.5 μm-15 μm) and is capable of current expansion. The window layer is not a necessary film for the element, which can be chosen based on the process parameters.
[0069] Referring to Table 1 for the optical-electrical characteristics of the 42×42 mil large-power quaternary LED element structure. As shown in Table 1, based on the flowing current results of the first electrode and second electrode after being powered on, the element emits red light with an average peak wavelength of 685.6 nm. When the 350 mA current flows through in forward direction, the average forward voltage value is 2.25 V and the output power is 250.3 mW.
[0000]
TABLE 1
VF/V
Po/mW
WLD/nm
WLP/nm
No. 1
2.26
248.5
656.2
686.0
No. 2
2.23
252.1
656.2
685.1
Average
2.25
250.3
656.2
685.6
Embodiment 2
[0070] In comparison with Embodiment 1, t the following is the same: in the 42.times.42 mil quaternary LED element structure of this embodiment, the pair number of the alternating-layer (of strained light-emitting layer and barrier layer) structure is 6. The structure of each pair is 60 nm thick and the total thickness is 360 nm. The difference is that: the strained light-emitting layer is Ga X In (1-X) As Y P (1-Y) (X=0.5 and Y=0.025). Based on the flowing current results of the first electrode and second electrode after being powered on, the element emits red light with average main wavelength of 680.2 nm and average peak wavelength of 714.9 nm. When the 350 mA current flows through in forward direction, the average forward voltage value is 2.22 V and the output power is 232.7 mW.
Embodiment 3
[0071] In comparison with Embodiment 1, the difference is that: the strained light-emitting layer of the 42.times.42 mil quaternary LED element structure of this embodiment is Ga X In (1-X) As Y P (1-Y) (X=0.5 and Y=0.04).
[0072] Refer to Table 2 for the optical-electrical characteristics of the 42.times.42 mil quaternary LED element structure. As shown in Table 2, based on the flowing current results of the first electrode and second electrode after being powered on, the element emits red light with average peak wavelength of 722.0 nm. When the 350 mA current flows through in forward direction, the average forward voltage value is 2.18 V and the output power is 216.5 mW.
[0000]
TABLE 2
VF/V
Po/mW
WLD/nm
WLP/nm
No. 1
2.19
215.7
693.7
721.7
No. 2
2.20
222.7
697.4
723.5
No. 3
2.16
220.1
701.7
723.5
No. 4
2.19
207.6
691.5
719.3
Average
2.19
216.5
696.1
722.0.
Embodiment 4
[0073] In comparison with Embodiment 3, the difference is that: the strained light-emitting layer of the 42.times.42 mil quaternary LED element structure of this embodiment is Ga X In (1-X) As Y P (1-Y) (X=0.5 and Y=0.05). Based on the flowing current results of the first electrode and second electrode after powering on, the element emits red light with average main wavelength of 712.3 nm and average peak wavelength of 739.5 nm. When the 350 mA current flows through in forward direction, the average forward voltage value is 2.21 V and the output power is 202.2 mW.
Embodiment 5
[0074] In comparison with Embodiment 3, the difference is that: in the 42.times.42 mil quaternary LED element structure of this embodiment, the pair number of alternating-layer (of strained light-emitting layer and barrier layer) structure is 9. The structure of each pair is 50 nm thick and the total thickness is 450 nm. Based on the flowing current results of the first electrode and second electrode after powering on, the element emits red light with average main wavelength of 701.5 nm and average peak wavelength of 733.5 nm. The saturation current is above 2,000 mA. When the 350 mA current flows through in forward direction, the average forward voltage value is 2.24 V and the output power is 223.9 mW.
[0075] To sum up, in the LED element structure for improving photosynthesis during plant cultivation, the peak light-emitting wavelength can be controlled within 650-750 nm by adjusting the composition of strained light-emitting layer, component value range and the pair number and thickness range of the alternating-layer (of strained light-emitting layer and barrier layer) structure, thereby achieving high output power. In addition, the material is helpful for improving life stability due to the lack of Al component.
Embodiment 6
[0076] The larger is Y value in the strain light-emitting layer Ga X In (1-X) As Y P (1-Y) , the narrower is the material gap, and the longer is the light emitting wavelength. Moreover, mismatch degree between the light emitting portion and base gets larger, and lattice growth quality of material gets poorer. As evidenced by experiment, as Y changes from 0 to 0.1, mismatch degree of the light emitting portion material increases gradually and lattice growth quality gets poorer. As the comparison examples No. 1˜No. 8 in Table 3 shown, when b value of the barrier layer (Al A Ga 1-A ) B In (1-B) P and total thickness of the alternating laminated structure in light emitting portion (MQW structure) remain unchanged, if Y is 0.01, light emitting efficiency is highest.
[0077] With As added in the light emitting layer, lattice constant of the strain light-emitting layer in the light-emitting zone is larger than that of GaAs, thus generating compression strain. Therefore, to reduce such compression strain, a barrier layer (Al A Ga 1-A ) B In (1-B) P is designed, wherein, 0.5<B≦0.52, i.e., lattice constant of the barrier layer is less than that of the GaAs base, thus generating tension strain. With a combination of the light-emitting zone and the barrier layer, effect and substrate mismatch degree get smaller to improve light-emitting efficiency and reliability of the material. As shown in Table 3, when B is 0.52, the light-emitting efficiency is highest.
[0078] For a MQW structure, total tension strain=compression strain of strain light-emitting layer (quantum well)*well thickness (positive)+tension strain of barrier layer (quantum barrier)*barrier thickness (negative). Total tension strain is preferred to be less than 500 ppm and preferably 100˜200 ppm as evidenced by an experiment. To achieve high-lighting efficiency LED with 650˜750 nm light-emitting wavelength, as shown in optimized experiment results, when B=0.52 in the barrier layer (Al A Ga 1-A ) B In (1-B) P and Y=0.01 in the light-emitting layer Ga X In (1-X) As X P (1-Y) , and total thickness is 360 nm, light-emitting effect of LED is best, reaching 1.5˜2 times compared with conventional method.
[0000]
TABLE 3
No.
1
2
3
4
5
6
7
8
Y value
0
0.01
0.025
0.01
0.01
0.01
0.01
0.01
[Light emitting
layer
Ga x In( 1−x )AS y P( 1−y )]
b value
05
0.5
0.5
0.5
0.52
0.53
0.52
0.52
[Barrier layer
(Al A Ga 1−A ) B In( 1−B )P]
Total thickness
240
240
240
240
240
240
360
450
of MQW/nm
(Po/VF/350 mA)
13.70%
28.80%
27.90%
28.40%
29.10%
28.30%
30.50%
27%
Light-emitting
efficiency
(Po/VF/350 mA)
Embodiment 7
[0079] It is common to pack the deep-blue-light, ultra-red-light and far-red-light LED chip with single wavelength one by one, and assemble individual packages on the light plate in various arrangements, as shown in FIG. 14 . Due to limited space and cost, it is better to use less LEDs in smaller size.
[0080] This embodiment discloses a LED for plant lighting, in which, ultra-red light (˜660 nm) and far-red light (˜730 nm) for plant lighting are realized in a single chip via laminated layer epitaxy.
[0081] With reference to FIG. 2 , a vertical LED chip according to the present invention is provided, comprising: a far-red-light epitaxial laminated layer 210 , a DBR semiconductor laminated layer 220 , a ultra-red-light epitaxial laminated layer 230 , a mirror structure 240 , a conductive bonding layer 250 , a conductive substrate 260 , an N-type electrode 271 and a P-type electrode 275 ,
[0082] Wherein, light-emitting wavelength of the far-red-light epitaxial laminated layer 210 is 710 nm˜750 nm, preferably, ˜730 nm, and that of the far-red-light epitaxial laminated layer 210 is 640 nm˜680 nm, preferably, ˜660 nm. In some embodiments, lighting area 210 a of the far-red-light epitaxial laminated layer 210 is less than or equals to lighting area 230 a of the ultra-red-light epitaxial laminated layer 230 . Preferably, lighting area 210 a of the far-red-light epitaxial laminated layer 210 is one-third of lighting area 230 a of the ultra-red-light epitaxial laminated layer 230 .
[0083] The DBR semiconductor laminated layer 220 is located between the far-red-light epitaxial laminated layer 210 and the ultra-red-light epitaxial laminated layer 230 . On the one hand, it reflects far red light emitted by the far-red-light epitaxial laminated layer 210 and prevents such light from being absorbed by the ultra-red-light epitaxial laminated layer 230 ; on the other hand, a high-resistance interface is formed as a current blocking layer to make current flow to the light-emitting zone of the ultra-red-light epitaxial laminated layer 230 , which has no far-red-light epitaxial laminated layer 210 , so as to improve luminance. Therefore, doping concentration of the DBR semiconductor laminated layer 220 is preferred to be not more than 5×10 17 , and preferably 4.00×10 17 .
[0084] The far-red-light epitaxial laminated layer 210 and the ultra-red-light epitaxial laminated layer 230 can be made of AlGaInP-based material, wherein, the far-red-light epitaxial laminated layer 210 , from up to bottom, comprises an N-type ohmic contact layer 212 , a first N-type electrode diffusion layer 213 , a first N-type covering layer 214 , a first light emitting layer 215 , a first P-type covering layer 216 and a first P-type ohmic contact layer 217 ; and the ultra-red-light epitaxial laminated layer 230 , from up to bottom. comprises a second N-type ohmic contact layer 232 , a second N-type electrode diffusion layer 233 , a second N-type covering layer 234 , a second light emitting layer 235 , a second P-type covering layer 236 , a P-type transition layer 237 and a second P-type ohmic contact layer 238 . An N-type etching stop layer 231 can be provided between the ultra-red-light epitaxial laminated layer 230 and the DBR semiconductor laminated layer 220 .
[0085] A step-shaped structure is provided between the far-red-light epitaxial laminated layer 210 and the ultra-red-light epitaxial laminated layer 230 for fabricating an electronic-connected structure 271 , wherein, one end is connected to the ohmic contact layer 261 of the far-red-light epitaxial laminated layer 210 , and the other end is connected to the ohmic contact layer 237 of the ultra-red-light epitaxial laminated layer 230 . Preferably, as lighting area 230 a of the ultra-red-light epitaxial laminated layer 230 is larger than lighting area 210 a of the far-red-light epitaxial laminated layer 210 , an extension bar 274 can be set on the ohmic contact layer 237 of the ultra-red-light epitaxial laminated layer 230 to ensure even light-emitting of the light emitting layer, as shown in FIG. 3 .
[0086] With reference to FIGS. 4-13 and fabrication method, the structure of the LED chip is described in detail below, mainly comprising: (I) epitaxial growth; (II) substrate transfer; (III) defining of light-emitting zone; (IV) electrode fabrication.
[0087] (I) Epitaxial Growth
[0088] Form an epitaxial structure on the growth substrate, as shown in FIG. 4 . The key of the structure is to grow an epitaxial layer as shown in Table 4 on the GaAs substrate in sequence. It should be noted that only one typical material is listed in the table below for material of each layer of the epitaxial structure. The material in actual application is not limited to the listed one but can be expended to any other necessary materials.
[0000]
TABLE 4
GaAs substrate
Thickness
Doping
Function
Layer
Material
(nm)
concentration
P-type ohmic
P-GaP
GaP:Mg
≧500
≧8.00 × 10 17
contact layer (2)
P-type transition
P-AlGaInP
AlGaInP:Mg
≦100
≧2.00 × 10 18
layer
P-type covering
P-AlInP(2)
AlInP:Mg
≧500
≧1.20 × 10 18
layer (2)
~660 nm light
GaInP-well
GaInP
≧8 × 3
—
emitting layer
AlGaInP-barrier
AlGaInP
≧8 × 3
—
N-type covering
N-AlInP(2)
AlInP:Si
≧500
≧1.60 × 10 18
layer (2)
N-type current
N-AlGaInP(2)
AlGaInP:Si
≧1000
≧1.00 × 10 17
diffusion layer (2)
N-type ohmic
N-GaAs(2)
GaAs:Si
≧100
≧6.00 × 10 18
contact layer (2)
N-type etching
N-GaInP(2)
GaInP:Si
≧100
≧1.00 × 10 18
stop layer (2)
DBR semiconductor
P-AlAs
AlAs:Mg
≧54.5 × 2
≦5.00 × 10 17
laminated layer
P-AlGaAs
AlGaAs:Mg
≧50.9 nm × 2
≦5.00 × 10 17
P-type ohmic
P-GaAs
GaAs:Mg
≧500
≧1.00 × 10 18
contact layer (1)
P-type covering
P-AlInP(1)
AlInP:Mg
≧900
≧1.20 × 10 18
layer (1)
~730 nm light
AlGaAs-well
AlGaAs
≧12 × 3
—
emitting layer (1)
AlGaInP-barrier
AlGaInP
≧13 × 3
—
N-type covering
N-AlInP(1)
AlInP:Si
≧500
≧1.60 × 10 18
layer (1)
N-type current
N-AlGaInP(1)
AlGaInP:Si
≧1000
≧1.00 × 10 17
diffusion layer (1)
N-type ohmic
N-GaAs(1)
GaAs:Si
≧100
≧6.00 × 10 18
contact layer (1)
N-type etching
N-GaInP(1)
GaInP:Si
≧100
≧1.00 × 10 18
stop layer(1)
[0089] (II) Substrate Transfer
[0090] In this step, bond the conductive substrate 260 and remove the growth substrate. To reach sufficient light emitting efficiency, a mirror structure is designed between the conductive substrate 260 and the epitaxial structure. In the embodiments below, at first, fabricate a mirror structure before substrate transfer. Details are as follows.
[0091] At first, on the surface of the second P-type ohmic contact layer 238 of the epitaxial structure, plate a light-transmission dielectric layer, and make a hole on the dielectric layer to remove the plated P-type metal ohmic contact layer (such as AuZn) and metal mirror layer (such as Au) to form a mirror structure 240 . According to a variant, deposit a transparent conducing layer (such as ITO) and a metal mirror layer (such as Ag) on the surface of the second P-type ohmic contact layer 238 in sequence to form another mirror structure.
[0092] Next, plate a bonding layer 250 on the mirror structure 240 , and perform bonding for the conductive substrate 260 with a bonding layer to complete metal bonding. The structure is shown in FIG. 5 . The metal bonding layer 250 can be made of Au/Au, Au/In, Au/Sn, Ni/Sn.
[0093] Remove GaAs substrate with alkaline solution and the first N-type etching stop layer 211 with hydrochloride acid solution and expose the first N-type ohmic contact layer 212 to complete substrate transfer, as shown in FIG. 6 .
[0094] (III) Defining of Light-Emitting Zone
[0095] Preset a far-red-light light-emitting zone 210 a on surface of the first N-type ohmic contact layer 212 of the epitaxial structure, and remove the first N-type ohmic contact layer 212 , the first N-type current diffusion layer 213 , the first N-type covering layer 214 , the first light emitting layer 215 , the first P-type covering layer 216 of the far-red-light light-emitting zone 210 to expose the first P-type ohmic contact layer 217 , as shown in FIG. 7 . The far-red-light light-emitting zone 210 a can be referred to FIG. 3 .
[0096] (IV) Electrode Fabrication
[0097] At first, fabricate a BeAu metal layer 272 on surface of the first P-type ohmic contact layer 217 , and form ohmic contact with the first P-type ohmic contact layer 217 after annealing, as shown in FIG. 8 .
[0098] Next, preset a ultra-red-light light-emitting zone 230 a on surface of the first P-type ohmic contact layer 217 and remove the first P-type ohmic contact layer 217 , the DBR semiconductor laminated layer 220 and the second N-type etching stop layer 231 of ultra-red-light light-emitting zone 230 a to expose the second N-type ohmic contact layer 232 , as shown in FIG. 9 . Remove the first P-type ohmic contact layer 217 and the DBR semiconductor laminated layer 220 with phosphoric acid solution, and remove the second N-type etching stop layer 231 with hydrochloride acid solution.
[0099] Remove the second N-type ohmic contact layer 232 with LIT Litho or phosphoric acid solution and leave the ohmic contact zone for patterning, as shown in FIG. 10 . The remaining portion can be referred to corresponding areas of the electronic-connected structure 273 and the electrode extension bar 274 as shown in FIG. 3 .
[0100] Next, evaporate GeAu on the first N-type ohmic contact layer 212 as the N-type electrode 271 , and form GeAu metal on the second N-type ohmic contact layer 232 , and connect it to the BeAu metal layer 272 on surface of the first P-type ohmic contact layer 217 as an electronic-connected structure 273 and an electrode extension bar 274 . Form ohmic contact after annealing, as shown in FIG. 11 .
[0101] Next, singularize the chip and remove part of the second N-type electrode diffusion layer 233 , the second N-type covering layer 234 , the second light emitting layer 235 , the second P-type covering layer 236 and the P-type transition layer 237 , till the second P-type ohmic contact layer 238 for patterning, as shown in FIG. 12 .
[0102] In some embodiments, form a light-intensifying structure on surfaces of the first N-type electrode diffusion layer 213 and the second N-type electrode diffusion layer 233 with hydrochloride acid solution, as shown in FIG. 13 .
[0103] Last, form a P-type electrode 275 on back of the conductive substrate 260 to complete a vertical LED chip for plant lighting.
[0104] With a combination of epitaxial growth of ultra-red-light and far-red-light laminated layer and chip fabrication, this embodiment reduces number of packages and area of plant lighting plate, and therefore cut cost.
[0105] All references referred to in the present disclosure are incorporated by reference in their entirety. Although specific embodiments have been described above in detail, the description is merely for purposes of illustration. It should be appreciated, therefore, that many aspects described above are not intended as required or essential elements unless explicitly stated otherwise. Various modifications of, and equivalent acts corresponding to, the disclosed aspects of the exemplary embodiments, in addition to those described above, can be made by a person of ordinary skill in the art, having the benefit of the present disclosure, without departing from the spirit and scope of the disclosure defined in the following claims, the scope of which is to be accorded the broadest interpretation so as to encompass such modifications and equivalent structures. | A light-emitting diode (LED) for plant illumination includes a substrate, and a PN-junction light-emitting portion over the substrate. The light-emitting portion has a strained light-emitting layer with a component formula of Ga X In (1-X) As Y P (1-Y) (0<X<1 and 0<Y<1), and a barrier layer, forming a 2˜40-pair alternating-layer structure with the strained light-emitting layer. | 8 |
FIELD OF THE INVENTION
This invention relates to hydrocolloid adhesive compositions having a variety of medical uses, particularly in the field of wound dressings, incontinence and ostomy care. More specifically, this invention relates to hydrocolloid adhesive compositions comprising a rubbery elastomeric base having dispersed therein one or more water soluble or water swellable hydrocolloid powders.
BACKGROUND ART
Hydrocolloid adhesive compositions have been known for many years. Chen, in U.S. Pat. No. 3,339,549 discloses a blend of a rubbery elastomer such as polyisobutylene and one or more water soluble or water swellable hydrocolloids such as a powdery mixture of pectin, gelatin and carboxymethylcellulose. The adhesive mass has a water-insoluble film applied to one surface. A composition of this type is available commercially from E. R. Squibb & Sons Inc. under the trademark "Stomadhesive" and is used as a skin barrier around stomas to prevent skin breakdown by the corrosive fluids discharged by the stoma.
In hydrocolloid adhesive compositions of this type, the polyisobutylene provides the adhesive properties and the dispersed hydrocolloid powders absorb fluid. These compositions are gaining increasing acceptance as wound dressings for dermal ulcers, burns and other exudative wounds.
One major problem which has been encountered with conventional hydrocolloid adhesive compositions is their susceptibility to breakdown upon exposure to wound exudate and body fluids. When the compositions are used as skin barriers, e.g., around stomas, absorption of fluid is desirable, but excessive swelling causes the composition to lose its moisture seal with the skin. Leakage occurs and the barrier must be replaced more often than is desirable.
Conventional hydrocolloid compositions used as wound dressings in the treatment of, for example, burns, dermal ulcers and pressure sores tend to dissolve upon exposure to wound exudate and form a gel on the surface of the wound. When the dressing is removed, a residue remains on the wound requiring removal, typically by irrigation. When this breakdown occurs the dressings may also lift off the wound and allow leakage of wound exudate onto clothing and bedding.
A number of attempts have been made to improve the integrity of hydrocolloid compositions.
U.S. Pat. Nos. 4,192,785 and 4,551,490 describe incorporating into the hydrocolloid composition a cohesive strengthening agent such as natural or synthetic fibrous material, finely divided cellulose, crosslinked dextran, crosslinked carboxymethylcellulose or a starch-acrylonitrile graft copolymer. The cohesive strengthening agent is said to control the rate of hydration of the composition thereby increasing resistance to breakdown by body fluids.
U.S. Pat. No. 4,477,325 describes incorporating into the hydrocolloid composition a mixture of a copolymer resin of ethylene and vinyl acetate (EVA). After mixing and molding, the composition is subjected to ionizing radiation to form crosslinked polymer networks of the EVA or EVA with another crosslinkable resin. The crosslinked matrix is said to provide controlled swelling.
U.S. Pat. No. 4,496,357 describes the incorporation of fumed silica into hydrocolloid compositions to control swelling.
Generally speaking, these prior methods of improving the integrity of hydrocolloid dressings all involve crosslinking or otherwise strengthening the matrix of the composition to control swelling upon contact with body fluids. This approach tends to limit the absorption capacity of the composition, which is not always desirable, particularly when the composition is used as a wound dressing on highly exudative wounds.
SUMMARY OF THE INVENTION
According to the present invention the integrity of hydrocolloid adhesive compositions is improved through the judicious selection of the hydrocolloid particles used in the compositions. There is provided a pressure-sensitive adhesive composition comprising a rubbery elastomer having dispersed therein water absorbable or water swellable hydrocolloid particles wherein at least some of the hydrocolloid particles are polycationic hydrocolloid particles. Compositions of the invention have an absorbency value (hereinafter defined) of at least 180 percent and an integrity value (hereinafter defined) of at least 60 percent. The polycationic hydrocolloid particles preferably comprise at least 10 percent by weight of the composition. The total amount of hydrocolloid particles preferably comprises at least 20 percent by weight of the composition. For wound healing applications, greater absorbency is generally required and a total hydrocolloid concentration of at least 40 percent by weight is preferred.
Preferred compositions of the invention contain a mixture of hydrocolloid particles, including polycationic and polyanionic hydrocolloid particles. Especially preferred mixtures comprise polycationic, polyanionic and neutral hydrocolloid particles in approximately equal proportions.
The preferred polycationic hydrocolloid for use in the compositions of the invention is a water soluble chitosan salt such as chitosan malate or chitosan glutamate. Especially preferred polyanionic and neutral hydrocolloid particles comprise pectin and gelatin, respectively.
When the hydrocolloid compositions of the invention are used for wound healing, it is preferred to cover one surface of the composition with a backing which is preferably moisture vapor permeable.
Compositions of the invention exhibit greater resistance to biological fluids than comparable hydrocolloid adhesive compositions of the prior art which do not contain polycationic hydrocolloid particles. Wound dressings made from compositions of the present invention exhibit lower rates of wound exudate leakage during use than dressings made from such prior art compositions. Longer wear time is provided and less clean up is required upon removal of the dressing since less residue is left in the wound bed.
Compositions of the present invention provide surprisingly increased integrity without a concomitant decrease in absorbency. In fact, because the compositions maintain their integrity longer, they are actually able to absorb more fluid over extended periods of time than comparable prior art compositions without polycationic hydrocolloid particles.
In addition to increased integrity and resistance to breakdown by body fluids, preferred compositions of the present invention containing chitosan particles exhibit antimicrobial properties, and may also exhibit hemostatic, immunopotentiating, endotoxin binding and enhanced wound healing properties.
DETAILED DESCRIPTION
The hydrocolloid adhesive compositions of the present invention comprise a blend of at least two basic ingredients, viz., the rubbery elastomeric adhesive matrix and the powdery polycationic hydrocolloid. In most oases, the polycationic hydrocolloid powder will be mixed with other hydrocolloid powders to provide optimum results in terms of absorbency and integrity.
Materials for forming the rubbery elastomeric adhesive matrix are well known and described, for example, in U.S. Pat. Nos. 3,339,546 and 4,253,460. Both natural or synthetic rubber or mixtures thereof are useful, also Kratons (block copolymers of styrene/butadiene and the like available from Shell Chemical Company), polybutene and polyacrylates may be used. Tackifiers, plasticizers and other materials known in the art for incorporation in the rubbery elastomeric matrix may also be used (See, for example, U.S. Pat. Nos. 4,231,369 and 4,551,490). Polyisobutylene is particularly useful as the rubbery elastomeric matrix. Preferably, the polyisobutylene is a mixture of low molecular weight polyisobutylene (viscosity average molecular weight of about 10,000 to 12,000) and a higher molecular weight polyisobutylene (viscosity average molecular weight of about 80,000 to 100,000) in a ratio of about four to one. Suitable low and high molecular weight polyisobutylene pressure sensitive adhesives are available from Exxon Chemical Company under the tradenames Vistanex LM and Vistanex L-100, respectively.
The rubbery elastomer preferably comprises about 30 to 50 percent by weight of those compositions used as wound dressings, and as much as 80 percent by weight of compositions used for ostomy care and related applications. When the elastomer is present in amounts below about 35 percent, the composition tends to exhibit inadequate adhesive properties. For wound dressing applications, it is desirable to minimize the amount of elastomer present, consistent with achieving adequate adhesive properties, in order to maximize the level of hydrocolloid, thereby achieving maximum fluid absorbency.
The improvement in integrity associated with the compositions of the present invention is attributable to the polycationic hydrocolloid particles contained in the compositions, particularly when mixed with anionic hydrocolloid particles or a blend of anionic and neutral hydrocolloid particles. The polycationic hydrocolloid is preferably a chitosan salt. Water soluble salts of chitosan, such as chitosan malate or chitosan glutamate are especially preferred. Improved composition integrity has also been observed with the polycationic hydrocolloid DEAE-Dextran. Other polycationic hydrocolloids which may be useful include any cationic-substituted hydrocolloid.
The polycationic hydrocolloid preferably comprises at least 30 percent of all hydrocolloids present, and in the case of wound dressing applications, should comprise at least 10, and preferably between 15 and 25, percent by weight of the total composition. Examples of other hydrocolloids which may be included in the compositions are neutral hydrocolloids such as gelatin, locust bean gum and guar gum, and polyanionic hydrocolloids such as pectin, carboxymethylcellulose, alginate, carageenan, xanthan gum, tragacanth gum, or mixtures of neutral and polyanionic hydrocolloids. The best results are obtained with a mixture of gelatin, chitosan malate and pectin.
The amount of hydrocolloid present in the composition for wound healing applications is preferably as large as possible consistent with maintaining adequate adhesive properties. This amount has been found to be about 60 percent by weight of the compositions. For other applications, e.g., skin barriers, concentrations as low as 20 may be useful.
Compositions of the invention may also contain minor amounts of other ingredients such as antioxidants, deodorants, perfumes, antimicrobials and other pharmacologically active agents as is well known in the art.
Compositions of the invention are made by compounding the pressure sensitive adhesive and any thermoplastic elastomer with a heavy duty mixer until a homogeneous blend is obtained. Small portions of a dry-blended premix of hydrocolloid particles are added and milling continued until a homogeneous dispersion of the particles in the adhesive phase is obtained. The blended adhesive mass is then molded into sheets for further conversion into wound dressings or formed into shapes such as strips, rings, etc., by any number of means commonly used for converting plastics and elastomers into shapes such as compression or injection molding.
The compositions are preferably sterilized by gamma irradiation at between 2.5 and 4 MRad. Ethylene oxide and E-Beam irradiation may also be used.
The invention is further illustrated by reference to the accompanying drawings wherein like reference numerals refer to like elements.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a wound dressing incorporating the hydrocolloid adhesive composition of the present invention;
FIG. 2 is an exploded side view of the dressing of FIG. 1;
FIG. 3 is a top view of an alternative embodiment of a wound dressing incorporating the hydrocolloid adhesive composition of the present invention; and
FIG. 4 is an exploded side view of the dressing of FIG. 3.
Referring to FIGS. 1 and 2, wound dressing 10 comprises an oval-shaped sheet 12 of the hydrocolloid adhesive composition of the present invention. Laminated to the top side (side facing away from the skin when the dressing is in use) is a slightly larger oval-shaped transparent film backing 14. An intermediate layer 16 of a conventional pressure-sensitive skin adhesive is used to facilitate lamination. The peripheral portion of the film backing 14 and adhesive layer 16 extends beyond the hydrocolloid sheet 12 to assist in adhering the hydrocolloid sheet 12 to the skin. A conventional release liner 18 is used to protect the exposed surface of the hydrocolloid sheet 12 and the exposed portion of the adhesive layer 16 prior to use. Delivery sheet 20 is attached to the top side of film backing 14 to prevent wrinkling and curling of the edges of backing 14 and adhesive layer 16 after removal of release liner 18. Delivery sheet 20 is divided into two sections of approximately equal size and heat-sealed to the top side of film backing 14. Both sections have a non-heat-sealed edge 22 at the center of the dressing to form handles which facilitate grasping and removal of the delivery sheet. Delivery sheet 20 supports the exposed periphery of backing 14 and adhesive layer 16 during application of the dressing to the patient. Once the dressing is in place on the skin, delivery sheet 20 is removed.
Separation of the release liner 18 from the hydrocolloid sheet 12 and adhesive layer 16 of the dressing 10 is facilitated by two tabs 24 and 26. Tab 24 comprises aligned rectangularly-shaped extensions of each of the delivery sheet 20, film backing 14 and adhesive layer 16, and further comprises a stiffening member 28 adhered to the adhesive layer 16 to facilitate separation of the tab members from each other. The second tab 26 is aligned with tab 24 and comprises a rectangularly-shaped extension of release liner 18. A perforation line 30 separates tab 24 from the main oval section of the dressing. Tab 24 provides an area for the person applying the dressing to hold onto without touching or otherwise contaminating the adhesive 14 and hydrocolloid sheet 12 in the main oval portion of the dressing. After the dressing is in place on the patient, tab 24 can be separated from the main oval portion of the dressing along perforation line 30.
The dressing illustrated in FIGS. 1 and 2 is the presently preferred embodiment of the invention. The oval shape reduces dressing size and minimizes edge lift.
The film backing 14 is preferably a highly moisture vapor permeable film of, for example, porous polyethylene such as that disclosed in U.S. Pat. No. 4,539,256 or polyurethane such as that described in U.S. Pat. Nos. 3,645,535 or 4,598,004. Moisture vapor permeable films of this type allow the wound exudate to evaporate through the dressing and reduce the pooling of exudate under the dressing. The moisture vapor transmission rate of the backing is preferably at least 500 grams/square meter/24 hours when measured at 40° C. and 80 percent humidity differential. Film backing 14 is preferably about 1 mil (0.0256 mm) thick.
Adhesive layer 16 is also preferably moisture vapor permeable so as not to detract significantly from the moisture vapor permeability of the film backing 14. Suitable medical adhesives of this type such as the copolymer acrylate adhesive and polyvinyl ether adhesive described in U.S. Pat. Nos. 4,598,004 and 3,645,535, respectively, are well known. The adhesive is preferably about 1-3 mils (0.025-0.075 mm) thick.
Delivery sheet 22 is preferably a polyester-film with a polyethylene-ethylvinyl acetate heat seal coating available commercially from 3M, under the trademark Scotchpack 1220.
Hydrocolloid sheet 12 preferably has the composition of Example 14 below and has a thickness between 40 and 70 mils (1.0-1.75 mm).
The dressing of FIGS. 3 and 4 represents an alternative embodiment of a wound dressing which incorporates the hyrocolloid adhesive composition of the present invention. Dressing 32 comprises a square sheet 34 of the hydrocolloid adhesive composition. A square film backing 36 of the same dimensions as the hydrocolloid sheet is laminated to the top surface (facing away from the skin) of the hydrocolloid sheet by adhesive layer 38. Release liner 40 covers the exposed surface of hydrocolloid sheet 34 and extends outwardly from the hydrocolloid sheet on all sides to facilitate grasping of the liner 40 and removal thereof prior to application of the dressing to the wound. The materials which can be used to form film backing 34 and adhesive layer 38 are essentially the same as those discussed above in connection with the embodiment of FIGS. 1 and 2. The dressing of FIG. 3 is cheaper to manufacture than the dressing of FIG. 1 and is also easier to cut to the dimensions of the wound.
The hydrocolloid adhesive compositions of the present invention exhibit increased integrity over similar prior art compositions without a polycationic hydrocolloid. Generally speaking, compositions of the invention also exhibit increased absorbency over such prior art compositions. The integrity and absorbency of the compositions were determined according to the following test procedures.
INTEGRITY TEST
Preweighed(W i ) test samples of the dressing 2.54 cm×2.54 cm) are placed in an eight ounce bottle containing fifty milliliters of phosphate buffered saline solution (pH 7.4) available from Sigma Chemical Company. The bottles are capped and agitated on a bottle roller at 50 rpms for a period of eighteen hours. The test sample is removed, weighed, dried in a circulating air oven maintained at 100° C. and 10 percent relative humidity until dry (4-6 hours) and weighed(W f ).
The Integrity Value of the sample is calculated using the following equation: ##EQU1## Compositions of this invention exhibit an Integrity Value of at least 60 percent and preferably 80 percent.
ADSORPTION TEST
Preweighed(W i ) test samples (2.54 cm×2.54 cm) of the dressing are placed in an eight ounce bottle containing fifty milliliters of phosphate buffered (pH 7.4) saline solution available from Sigma Chemical Company. The bottles are capped and allowed to stand without agitation. Test samples are removed at two hour intervals, weighed(W t ) and returned to the bottle. The Absorbency Value is calculated using the following formula: ##EQU2##
Twenty-four hour absorbency data is reported for the dressing compositions listed in Table 1 below. Compositions of the present invention exhibit a twenty-four hour absorbency value of at least 180 percent and preferably 300 percent.
EXAMPLES 1-3, 10-21 and 29 AND COMPARATIVE EXAMPLES 4-9 and 22-28
Wound dressings incorporating the hydrocolloid adhesive compositions of the invention and comparative dressings (Examples 4-9 and 22-28) as identified in Table I below were made according to the same general procedure.
The adhesive phase of the dressing was prepared by compounding a mixture of the pressure sensitive material and a thermoplastic elastomer on a two-roll rubber mill without supplemental heating or cooling until a homogeneous blend of the two components was obtained (typically 1-2 minutes). Small portions of a blended premix of the hydrocolloid powders, which had been previously prepared by dry blending the powders in the specified weight ratios, were then added to the adhesive phase and the milling continued until a homogeneous dispersion of the powders in the adhesive phase obtained. The blended adhesive mass was then removed from the rubber mill and formed into approximately 60 mil (1.5 mm) thick sheet stock material by compression molding the adhesive mass at approximately 150° C. and approximately 2,000 psi between two sheets of silicone release paper. The release paper was removed from one side of the adhesive sheet stock and replaced with a backing material, preferably a high moisture vapor permeable polyurethane film having a pressure sensitive adhesive on the surface contacting the adhesive stock, e.g., Tegaderm Transparent Dressing manufactured by 3M. The resulting laminate structure was then die cut into the desired shapes and sterilized by exposure to gamma radiation.
TABLE 1__________________________________________________________________________Examples 1-29__________________________________________________________________________ Example Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17__________________________________________________________________________Adhesive MatrixVistanex LM-MH.sup.1 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32Vistanex L-100.sup.2 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8Hydrocolloid NeutralGelatin.sup.3 40 20 -- 20 20 -- 20 20 20 20 20 20 20 20 20 20 20Locust Bean Gum.sup.4 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --Guar Gum.sup.5 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --PolyanionPectin.sup.6 -- -- -- 20 -- 30 20 20 20 -- -- -- 20 20 -- -- -Na CMC.sup.7 -- -- -- -- 20 30 20 20 -- 20 20 -- -- -- -- -- --Na Alginate.sup.8 -- -- -- 20 20 -- -- -- -- -- -- 20 -- -- -- -- --Carageenan.sup.9 -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20 -- --Xanthan Gum.sup.10 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20 --Tragacanth Gum.sup.11 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20Aqualon C.sup.12 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --PolycationChitosan Malate.sup.13 20 40 60 -- -- -- -- -- -- -- 20 20 20 -- 20 20 20Chitosan Glutamate.sup.14 -- -- -- -- -- -- -- -- -- -- -- -- -- 20 -- -- --Chitosan Lactate.sup.15 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --DEAE - Dextran.sup.16 -- -- -- -- -- -- -- -- 20 20 -- -- -- -- -- -- --Percent Integrity.sup.# 92 80 70 36 10 5 19 45 82 92 85 69 93 85 89 92 76Absorbency 180 270 310 390 160 270 240 320 110 240 490 390 360 370 330 350 320__________________________________________________________________________ Example Number 18 19 20 21 22 23 24 25 26 27 28 29__________________________________________________________________________ Adhesive Matrix Vistanex LM-MH.sup.1 32 32 32 32 32 32 32 32 32 32 32 32 Vistanex L-100.sup.2 8 8 8 8 8 8 8 8 8 8 8 8 Hydrocolloid Neutral Gelatin.sup.3 -- -- -- 20 -- 20 20 20 -- -- 20 20 Locust Bean Gum.sup.4 -- 20 -- -- -- -- -- -- -- 30 20 -- Guar Gum.sup.5 20 -- -- -- -- -- -- -- 30 -- -- 20 Polyanion Pectin.sup.6 20 20 20 10 30 20 20 20 -- -- -- -- Na CMC.sup.7 -- -- -- -- -- 5 10 15 -- -- -- -- Na Alginate.sup.8 -- -- 20 10 30 -- -- -- -- -- -- -- Carageenan.sup.9 -- -- -- -- -- -- -- -- -- -- -- -- Xanthan Gum.sup.10 -- -- -- -- -- -- -- -- -- -- -- -- Tragacanth Gum.sup.11 -- -- -- -- -- -- -- -- -- -- -- -- Aqualon C.sup.12 -- -- -- -- -- 15 10 5 -- -- -- -- Polycation Chitosan Malate.sup.13 20 20 20 20 -- -- -- -- 30 30 20 20 Chitosan Glutamate.sup.14 -- -- -- -- -- -- -- -- -- -- -- -- Chitosan Lactate.sup.15 -- -- -- -- -- -- -- -- -- -- -- -- DEAE - Dextran.sup.16 -- -- -- -- -- -- -- -- -- -- -- -- Percent Integrity.sup.# 90 96 89 89 0 0 0 0 55 30 0 80 Absorbency 360 370 360 360 220 500 500 520 245 --* 370 280__________________________________________________________________________ .sup.# Average of three replicate tests *Hydrocolloid adhesive dissolved off backing .sup.1 Polyisobutylene PSA available from Exxon Chemical Co., Viscosity average MW 10,000-11,700 .sup.2 Polyisobutylene rubber available from Exxon Chemical Co., Viscosit average MW 81,000-99,000 .sup.3 Gelatin 150 Bloom A available from Atlantic Gelatin .sup.4 Available from Sigma Chemical Co. .sup.5 Available from Sigma Chemical Co. .sup.6 Pectin USP100 available from Hercules, Inc. .sup.7 Cellulose Gum CMC #7H4XF available from Hercules, Inc. .sup.8 Protanal SF 40 available from Proton Laboratories .sup.9 Carageenan type II, available from Sigma Chemical Co. .sup.10 Available from Sigma Chemical Co. .sup.11 Available from Sigma Chemical Co. .sup.12 Available from Hercules, Inc. .sup.13 Available from Protan Laboratories .sup.14 Available from Protan Laboratories .sup.15 Available from Protan Laboratories .sup.16 Available from Sigma Chemical Co.
Examination of the Integrity data generated for the samples reported in Table 1 shows that, in general, better integrity was obtained from compositions containing a polycationic hydrocolloid than from compositions without a polycationic hydrocolloid. Compositions containing a mixture of hydrocolloids including both polycationic and polycationic hydrocolloids, generally exhibit the best integrity. Example 13, which represents an optimized formulation for the dressings of the present invention, gives approximately double the integrity obtained from the dressing of Example 8 which has a composition similar to that used in a commercially available hydrocolloid dressing. (DuoDerm Hydroactive Dressing from E. R. Squibb & Sons, Inc.)
The absorbency of the dressing compositions, especially when considered in conjunction with the integrity data, further illustrates the improvement which the dressings of the present invention offer. Generally speaking, high absorbencies at 24 hours can be realized with dressing compositions based on mixtures of hydrocolloids which do not include polycationic hydrocolloids, but only at the expense of the integrity of the dressing. As such dressings lose integrity over time, absorbency is decreased. The preferred formulation for dressings of the present invention (Example 13) when compared to the DuoDerm product, did not show a significant difference in absorbency at 24 hours, but at 48 hours the composition of Example 13 showed a two-fold increase in absorbency. This increase in absorbency is directly related to the increased integrity of the composition of Example 13 over the Duoderm product. The actual results of the comparative study are shown in the following table.
TABLE 2______________________________________Absorbency (%) HoursComposition 2 4 6 8 23 48 72 144______________________________________Example 13 .97 1.55 2.04 2.40 3.60 5.26 5.29 5.54DuoDerm 1.36 2.06 2.44 2.59 3.19 2.18 1.23 1.12______________________________________Integrity (%) HoursComposition 6 24 32 40 48 120______________________________________Example 13 94.6 89.0 95.0 95.0 92.0 87.0DuoDerm 90.6 45.0 37.0 29.0 23.0 18.0______________________________________
EXAMPLE 27
The dressing composition of Example 13 was scaled up in an extrusion process as follows:
A hydrocolloid adhesive premix was prepared by compounding gelatin (25 weight percent) in Vistanex L-100 (75 weight percent) on a two roll mill with no supplemental heating or cooling until a homogeneous mixture was obtained (approximately 15 minutes). The premix was removed from the mill and cut into cubes approximately 2.54 cm×2.54 cm×2.54 cm.
A mixture of chitosan malate (1.87 parts), pectin (1.87 parts), gelatin (1.62 parts) and the previously described hydrocolloid adhesive premix (1 part) were charged into a 10 gallon Baker-Perkins double arm sigma blade mixer (mogul) and the mixture blended for two (2) minutes. The mogul was stopped, Vistanex LM-MH charged to the mogul (3.00 parts) and the mixture blended for an additional nine (9) minutes. The blended hydrocolloid adhesive (HCA), which had a final composition of 20 weight percent chitosan malate, 20 weight percent pectin, 20 weight percent gelatin, 8 weight percent Vistanex L-100 and 32 weight percent Vistanex LM-MH, was removed from the mogul and cut into strips prior to being fed into a 3.5 inch Davis-Standard Rubber Extruder to convert it into a sheet stock form. The HCA was cold-fed into the extruder and heated to about 70° C. as it was pumped to the extrusion die. The HCA was extruded into a nip roller assembly having a silicone release liner (Grade 8766 semi-bleached paper, 60#, coated on both sides, available from James River Corp., H. P. Smith Division) over the top roll and the product liner (2-6OBKG-157 and 99AM, silicone coated on both sides, available from Daubert Chemical Co.) over the bottom roll. The release liner was removed from the laminate construction and the HCA/product liner construction wound into 100 meter storage rolls. The HCA layer produced by this process was approximately 1.5 mm thick. Dressings of the present invention are prepared by laminating the HCA/product liner to a high moisture vapor permeable bandage such as that described in U.S. Pat. No. 4,499,896. The lamination is effected by assembling a construction having the adhesive component of the bandage in contact with the HCA component of the HCA/product liner laminate and passing the construction through a heated nip roll assembly. | Hydrocolloid adhesive compositions are disclosed comprising a rubbery elastomeric base having dispersed therein hydrocolloid particles, at least some of which are polycationic hydrocolloid particles. The compositions have enhanced resistance to breakdown by body fluids and are especially useful as wound dressings. | 0 |
FIELD OF THE INVENTION
The invention is in the field of leveling devices.
BACKGROUND OF THE INVENTION
The related art leveling devices have the deficiency of poor drag and drop performance. Simply put, the related art is susceptible to damage caused by the moment created by applying a force to the foot of the leveler by moving the support structure (i.e. furniture). Support within a furniture leg via a propel nut, for example, counteracts torque applied to the foot of a leveling device. Longer propel nuts may be used to provide better support as the foot is coupled to the propel nut with a threaded stud. However, longer propel nuts are difficult and expensive to form as they are stamped from sheet steel and drawn longer and longer by a progressive die. This is difficult however due to thinning of the material and long propel nuts are difficult to tap.
FIG. 1 is a partial cross-sectional view 100 of a prior art leveler 109 attached to a wood, plywood, or pressboard substrate 101 . Alternatively, levelers may be used with plastic substrates. The substrate 101 may be a furniture leg or support. The device may be, for instance, applied to industrial equipment. A propel nut 104 resides in a bore 102 of the substrate 101 . The propel nut has skives 105 which engage the bore 102 of the substrate and surrounding substrate material and which assist in retaining the propel nut in the substrates. The propel nut has a flange 107 which abuts exterior surface 106 of the substrate 101 . The propel nut is fixed in the substrate. The flange surface 108 engages the surface 106 of the substrate. A threaded stud 103 A is threaded into the propel nut 104 and is rotatably and translationally movable with respect to the propel nut.
The threaded stud 103 A includes an integral nut 109 A and floor engaging surface 109 B. Threads 103 extend from the nut 109 A to the end of the stud. The threaded stud 103 A rotates and moves translationally with respect to the internal threads of the propel nut. In this way the floor engaging surface 109 B may be positioned relative to the substrate (i.e. leg of the furniture) to adjust the height of the furniture with respect to the floor. When the propel nut is installed into the substrate there is a slight rotational movement of the skives 105 and the barrel of the nut as the nut is forced into the bore 102 of the substrate 101 . The height of the leveler is based on the translational movement of the threaded stud within the propel nut. Deformation 130 occurs in the substrate 101 near the surface of the propel nut as it is forced into the substrate.
FIG. 2 is a bottom view 200 of the prior art leveler in substrate 101 . The wood substrate has cracks 201 in the surface 106 and distortions 210 or bowing in the plane of the wood. The cracks or other disruptions in the surface are caused by dropping or sliding the furniture. Dropping applies a force generally along the axis of the threaded stud 103 A and dragging applies a force generally perpendicular to the axis of the threaded stud 103 A.
Propel nuts are used in the furniture industry to secure levelers in substrates. Propel nuts are shorter than the threaded studs which are inserted inside the propel nut so that adjustments may be made. The height of the prior art leveler is changed by adjusting the threaded stud relative to the propel nut.
When extended to its full length, the leveler is especially susceptible to bending or breaking which can damage either the substrate or the entire piece of furniture. The leveler is more susceptible when fully extended because the bending moment or torque which is applied when the furniture is moved by sliding it on the floor is large. Also, the furniture may be lifted and dropped which tends to fracture the substrate 101 .
Correcting a defect in an article supported and positioned by a leveler can be difficult, time consuming, labor intensive, and expensive. In some cases, the entire substrate or the furniture may have to be discarded and/or the furniture disassembled if a leg of the furniture is fractured.
Two approaches to solve the aforementioned problems involve the use of thicker side panels or longer propel nuts. Use of aforementioned thicker side panels adds to the weight of the substrate and can significantly add to the expense of the furniture produced. Longer propel nuts also contribute to increased cost in manufacturing the final piece of furniture.
Levelers for the legs or walls of furniture are also sometimes described as leveling mounts, swivel levelers, rigid levelers, adjustable feet, leveling pads, furniture glides, leg levelers, desk glides, table glides, furniture sliders, threaded T-nuts for wood legs, and low profile levelers. U.S. Pat. No. 4,991,365 to Jackson discloses a foot pad attached to a shaft portion for leveling panels in a relocatable wall. U.S. Pat. No. 6,129,431 to Hansen Jr. et al discloses the use of a built-in riser in the base of a wall section. U.S. Pat. No. 4,770,275 discloses the use of a riser in an adjustable ladder assembly. U.S. Pat. No. 5,138,814 to Giles et al. discloses the use of a nut-and-bolt type leveler consisting of a threaded bolt portion which cooperates with a nut against a washer to extend or retract a foot.
The structure of the instant invention and the advantages its provides will be readily apparent to a person of ordinary skill in the art when reference is made to the Summary of the Invention, Brief Description of the Drawings, Description of the Invention and Claims which follow hereinbelow.
SUMMARY OF THE INVENTION
A leveling device is disclosed and claimed which exhibits superior drag performance. An end cap is pressed onto an end of the threaded stud which is used in combination with a propel nut and a bore in the substrate. In this way, the effective length of the propel nut in the bore and the effective arm length is extended which counteracts a drag force applied to the foot of the device which engages the floor or the mounting surface. The end cap snugly fits within the bore of the substrate providing support while enabling rotational and translational movement of the threaded stud with respect to the propel nut.
Use of the device enables larger adjustment ranges through the use of longer threaded studs while providing improved performance in regard to drag tests.
A leveling device for leveling furniture includes a propel nut and threaded stud in a bore of a substrate. The threaded stud includes a nut for rotating the stud, a leveling surface for engaging the floor or other surfaces, and an end cap secured to the end of the stud. The distal (with respect to the foot) threaded stud includes a first end (top end) and a second end (bottom end). The top end is cylindrically shaped. The bottom includes a foot and an integral nut. The propel nut includes a flange which abuts on the outer surface of the substrate and skives which grip the bore.
The first end of the threaded stud is not threaded and passes through the propel nut when the treaded portion of the threaded stud interengages the propel nut. Then an end cap is pressed on the top end. The bottom end of the threaded stud contains a nut and a leveling surface.
Once assembled the leveling device is fit into the bore of a substrate by forcefully pressing the propel nut with skives on its barrel into the bore. The diameter of the cylindrical end of stud with the end cap pressed thereon is greater than the diameter of the threaded stud and at least as large as the diameter of the propel nut 104 . As a result, the end cap snugly engages the bore of the substrate when forced into the bore. The end cap is rotationally and translationally movable within the bore, so that the leveler and the threaded stud may be repositioned.
However, the end cap has a translational movement limitation. The end cap can not move past the top end of the propel nut, thus preventing the extraction of the threaded stud and foot. The nut surface 109 C can not move beyond the top end of the bore 102 . The end cap has a snug fit within the bore which prevents movement of the threaded stud.
The range of movement of the threaded stud is limited by the end cap as far as extension of the stud is concerned. Further, the range of movement of the threaded stud as far as the minimum extension is concerned is limited by the nut of the stud engaging the flange of the propel nut. The snug fit of the end cap in the bore prevents non-axial movement of the threaded stud and this then increases the stability and strength of the leveling device and improves its resistance to drag. One end (the lower end) of the end cap engages the propel nut and prevents the threaded stud from being removed and thus defines the maximum extension of the threaded stud. The end cap adds strength to the leveling system and helps prevent splitting of side panels if the furniture is dropped and especially if the furniture is dropped such that the foot strikes the floor at an angle. The threaded stud can not be removed or overextended from the leveling device. As a result, stability of the leveler is significantly increased.
Use of the device allows adjustability between a first full extended position of the stud and foot of the leveler and a second fully inserted position of the stud and foot of the leveler.
A method for forming and using the leveling device is disclosed and claimed. The method includes the steps of: threading a threaded stud into a propel nut, forming an end cap on a first end of the threaded stud, inserting and pressing the propel nut and end cap of the threaded stud into the bore of the substrate. Adjusting the leveling surface of the threaded stud is accomplished by turning the nut attached to the second of the threaded stud until the desired position is achieved.
It is an object of the instant invention to provide a leveling device which includes a propel nut, a threaded stud, and an end cap mounted on the threaded stud.
It is an object of the instant invention to provide a stable height adjustment device for a substrate containing a bore.
It is an object of the instant invention to provide level adjustment using an end cap on a threaded stud press fit within a bore in which the end cap has a diameter greater than the threaded stud.
It is an object of the instant invention to provide level adjustment of a substrate with a threaded stud in which one end contains a level adjustment surface and the other end of the threaded stud has a end cap which resides in a bore of the substrate.
It is an object of the instant invention to provide a method for forming a leveling device having a threaded stud, end cap, and propel nut.
It is an object of the instant invention to provide a leveling device which has superior drag resistance.
It is an object of the instant invention to provide a leveling device which is able to absorb a large bending moment which is created when the furniture in which it is installed is dragged along a floor to a new position.
It is an object of the instant invention to provide a leveling device which counteracts a large bending moment through the use of an end cap on the threaded stud.
It is an object of the present invention to provide a leveling device which may be installed for use and then shipped with the threaded stud retained therein.
It is an object of the invention to enable use of longer threaded studs which provide a greater range of height adjustment due to increased stability of the device.
It is an object of the present invention to obtain the functionality of a long propel nut using the end cap and a shorter propel nut.
These and other objects of the invention will be best understood when reference is made to the Brief Description Of The Drawings and Claims which follow hereinbelow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial cross-sectional view of a prior art leveler inserted and secured to a wood, plywood, or press board substrate.
FIG. 2 is a bottom view of the prior art leveler of FIG. 1 .
FIG. 3 is an exploded assembly view of the rolled end cap, propel nut, and threaded stud.
FIG. 3A is an assembled view of the end cap, threaded stud, and propel nut.
FIG. 3B is a top view of the threaded stud of FIG. 3A .
FIG. 3C is a cross-sectional view taken along the lines 3 C- 3 C of FIG. 3B of the threaded stud and propel nut assembly.
FIG. 4 is an exploded assembly view of the improved leveling device.
FIG. 4A is an assembled view of the improved leveling device.
FIG. 5 is exploded assembly view of the improved leveling device with a rolled end cap.
FIG. 5A is exploded assembly view of the improved leveling device with a press fit end cap.
FIG. 6 is perspective view of the assembled leveling device which uses a longer the threaded stud.
FIG. 6A is perspective view of the assembled leveling device of FIG. 6 .
FIG. 6B is a partial cross-sectional view of the assembled leveling device employing a long threaded stud completely inserted into the base of a substrate.
FIG. 6C is partial cross-sectional view similar to FIG. 6B with the threaded stud just about completely retracted.
FIG. 6D is a partial cross-section view of the assembled leveling device where a drag force is applied perpendicularly to the foot of the assembled device in a state of adjustment.
FIG. 6E is a partial cross-section view of the assembled leveling device where a drag force is applied perpendicularly to the foot of the assembled device in another state of adjustment.
FIG. 7 is a side view of another example of the leveling device.
FIG. 7A is a top view of FIG. 7 .
FIG. 7B is a side view of another example of the leveling device.
FIG. 7C is a top view of FIG. 7B .
FIG. 7D is a side view of another example of the leveling device.
FIG. 7E is a top view of FIG. 7D .
FIG. 8 is a perspective view of a desk with a leveler attached to the bottom of a side wall of the desk.
FIG. 8A is an enlarged cut-away perspective view of the assembled leveling device mounted in the side wall of the desk in FIG. 8 .
FIG. 8B is a perspective view of a piece of furniture.
FIG. 8C is an enlarged cut-away similar to FIG. 8B .
The drawings will be best understood when reference is made to the Description of the Invention and Claims below.
DESCRIPTION OF THE INVENTION
FIGS. 1-2 have been described above in connection with the Background of the Invention.
FIG. 3 is an exploded assembly view 300 of the rolled end cap 301 , propel nut 104 , and threaded stud 103 A. The rolled end cap 301 has a seam 302 . Propel nut 104 has internal threads 304 , a plurality of skives 105 , and a flange 107 . Flange 107 has a contact or engagement surface 108 for interengaging the substrate. See FIGS. 6B-6D . Threaded stud 103 A has a cylindrical end 120 , an end 303 , a nut 109 A, and a leveler 109 . It is specifically contemplated that levelers having a shape other than that described and shown in the drawings may be used. The cylindrical end 120 terminates in surface end 303 of the threaded stud as viewed in FIG. 3 . The diameter of the cylindrical end 120 is less than the diameter of threads 103 of the stud 103 A. Cylindrical end 120 of the stud 103 A is not threaded. The threaded stud is threaded from the nut 109 A to the cylindrical end 120 . The nut 109 A is part of the threaded stud adjacent to the leveler and has a hexagonal shape. Leveler 109 is disk shaped, has a diameter greater than nut 109 A, and is located on the bottom of the threaded stud. The leveler has a bottom surface 109 B which engages the mounting surface such as a floor. See FIG. 3C .
FIG. 3A is an assembled view 300 A of the end cap 301 , threaded stud 103 A, and propel nut 104 . Threads 103 extend from the nut 109 A to the cylindrical end 120 of the stud 103 A. End cap 301 is pressed onto the cylindrical end of stud 120 . End 303 is exposed at the top of the threaded stud. The threaded stud 103 A is threaded into the propel nut 104 . Flange 107 of the propel nut 104 is shown engaging nut 109 A in FIG. 3A . Nut 109 A is integral with leveler 109 . Leveler 109 is located at the bottom of the threaded stud 103 A and is integral therewith.
FIG. 3B is a top view 300 B of the assembled leveling device. The end 303 of the threaded stud is viewed in FIG. 3B . Rolled end cap 301 is located on the outer circumference of the cylindrical end 120 . Propel nut 104 is threadedly interconnected to threads 103 of stud 103 A. The position of the stud 103 A may be adjusted by rotating the threaded stud within the propel nut. Skives 105 are located around the circumference or barrel of the propel nut 104 . Surface 108 of the flange 107 of the propel nut 104 interengages the surface of the device into which it is installed. See FIGS. 6B-D . The diameter of the leveler 109 is greater than the diameter of the flange 107 of the propel nut 104 .
FIG. 3C is a cross-sectional view 300 C taken along the lines 3 C- 3 C of FIG. 3B of the threaded stud 103 A and propel nut 104 assembly. End 303 of the threaded stud 103 A and rolled end cap 301 are viewed in FIG. 3C . Rolled end cap 301 surrounds cylinder 120 and seam 302 is viewed therebetween. The internal threads 304 of the propel nut 104 are shown threadedly interengaging the threaded stud 103 A which extends therethrough. Skives 105 are located on the outer surface of the propel nut. The contact surface 108 of the flange 107 of the propel nut 104 is located above the leveler 109 . There are a few threads of the threaded stud shown in between the flange 107 and the top surface 109 of the nut 109 A on the threaded stud. The nut is located directly on top of the leveler 109 and is integral therewith. The outer diameter of the leveler is slightly larger than the diameter of the flange of the propel nut. The surface of the leveler 109 B is located at the bottom of the assembly and engages the floor.
FIG. 4 is an exploded assembly view 400 of the improved leveling device. Press fit end cap 401 is fitted over the cylindrical end 120 of the threaded stud. A larger diameter end cap may be used and will result in a tighter fit in bore 102 making rotational and translational movement of the stud 103 A more difficult but still possible. The press fit end cap has an internal and external radius. The external radius is roughly equivalent to the outer radius of the shaft of the propel nut which lies beneath the end cap.
Internal threads 304 line the inside of the propel nut 104 . Skives 105 are located on the upper part of the outer shaft (barrel) of the propel nut 104 . The cylindrical end 120 is not threaded and receives the press fit end cap. The threaded stud 103 A has a threaded area extending from after the cylindrical end 120 to nut 109 A. Nut 109 A has a hexagonal shape and is integral with the threaded stud 103 A which is integral with the leveler 109 .
Leveler 109 is disk shaped with a diameter greater than the nut 109 A, flange 107 of propel nut, shaft (barrel) of the propel nut, and end cap 301 / 401 .
FIG. 4A is an assembled view 400 A of the improved leveling device. The end cap 401 is press fit over the cylindrical end 120 of the threaded stud 103 A. Threads 103 are located intermediate end cap 401 and nut 109 A of the threaded stud. The propel nut is threaded onto the threaded stud. The flange 107 of the propel nut is shown abutting nut 109 A of the threaded stud 103 A.
FIG. 5 is an exploded assembly view 500 of the improved leveling device with a rolled end cap 301 . FIG. 5A is an exploded assembly view 500 A of the improved leveling device with a press fit end cap 401 . FIGS. 5 and 5A illustrate different stud lengths, different propel nuts, 504 , 504 A with different lengths, and different end caps 301 , 401 . Additionally, it will be noticed that the stud lengths and propel nut lengths of FIGS. 5 and 5A are longer than those shown in FIG. 3 .
FIG. 6 is perspective view 600 of the assembled leveling device with a longer threaded stud 103 A. The threaded stud in FIG. 6 is longer than the threaded stud in the leveling device of FIG. 4A or the leveling device in the Prior Art in Fig. 1 . A greater range of level adjustments that can achieved with the improved leveling device of FIG. 6 because of the support of the end cap within the bore 102 .
FIG. 6A is perspective view 600 A of the assembled leveling device employing a longer threaded stud 103 A as in FIG. 6 . Rolled end cap 301 is wrapped around and secured to cylindrical end of stud 120 as in FIGS. 4A and 6 . Propel nut 604 is illustrated closer to the top of the threaded stud 103 A showing an adjustment in the position of the propel nut from its position in FIG. 6 . Propel nut 604 is fixed in the substrate and the threaded stud is moved relative thereto. Threaded stud 103 A is adjustable in a plurality of positions with respect to the propel nut. The rolled end cap 301 at the end of threaded stud does not allow the threaded stud to move past the point where the bottom of the end cap 301 and the top of the propel nut 104 engage preventing complete extraction of the threaded stud. Threaded stud 103 A is limited in its translational positions with respect to the propel nut in that the rolled end cap 301 abuts against the top of the propel nut 604 or the nut 109 A engages against the flange 107 .
FIG. 6B is a perspective view 600 B of the threaded stud 103 A inserted into the bore 102 of a substrate 101 . The assembled leveling device uses a threaded stud 103 A. Rolled end cap 301 is located near the top of the bore 102 and this represents the fully inserted position of the foot 109 . The outer surface of the rolled end cap engages the bore 102 as indicated by reference numeral 601 . Propel nut 104 is fixed in position in the bore 102 of the substrate 101 . Skives 105 are illustrated as embedded into the substrate 101 . Slight deformation of the wood 130 is observed in the vicinity of the substrate 101 intermediate the shaft of the propel nut 104 and the bore 102 of the substrate 101 . Flange 107 of the propel nut abuts bottom surface 106 of the substrate 101 . The top of the nut 109 A abuts flange 107 of the propel nut 104 , Leveler 109 is integral with nut 109 A and bottom surface 109 B rests upon a surface (not shown).
The threaded stud is able to move in an up and down translational direction by rotating the nut 109 A which enables the threaded stud to move relative to propel nut 104 . The movement of the threaded stud 103 A with respect to the propel nut is limited by the position of the nut 109 A on the outside of the bore 102 and the position of the end cap 301 in the bore 102 of the substrate 101 .
End cap 301 is diametrically larger than the threaded stud 103 A. End cap 301 has a snug fit within bore 102 and is rotationally movable as the end cap 301 passes along the cylindrical bore 102 when the threaded stud 103 A rotates with respect to the interior threads of the propel nut 104 . The height of the substrate and leveling device is adjustable based on the length of the threads 103 of the threaded stud 103 A. As shown in FIG. 6B , the leveler is illustrated in a second position fully inserted into and through the propel nut. This second position provides the shortest possible leg height adjustment. At the lowest height adjustment position of the leveling device, the length of the threaded stud within the bore 102 of the substrate is at its maximum and this is referred to herein as the first position of the leveler. The leveler, which may be longer using the end cap, is fully adjustable in a range of positions between the first and second positions.
FIG. 6C is partial cross-sectional view 600 C of the threaded stud 103 A and propel nut 104 inserted into the plastic substrate 610 . In comparison to FIG. 6B , another height adjustment of the leveling device is shown in FIG. 6C . Rotating nut 109 A, adjusts the length of the threaded stud 103 A which extends into and out of the bore 102 of the substrate 101 . Adjustment of the nut 109 A enables different lengths of the threaded stud 103 A to extend beyond the bottom surface of the substrate 106 . In FIG. 6C , the leveling device has been adjusted by rotating the nut so as to provide a different height adjustment with respect to the substrate. In this view, it can be seen that the height of the leveling device is limited at the point where the bottom of the end cap 301 engages propel nut 104 . The height of the leveling device will reach its maximum when the bottom of end cap 401 abuts the propel nut 104 . At the maximum height of the leveling device and hence the device it supports, the length of the threaded stud 103 A within the bore of the substrate will be at its minimum. Reference numeral 601 B represents support of the bore on the end cap 601 B.
FIG. 6D is a partial cross-sectional view 600 D of the leveling device having a threaded stud 103 A where a force F is applied perpendicularly to the orientation of the threaded stud 103 A and bore 102 . The threaded stud 103 A illustrated in FIG. 6D has an increased length. Bore 102 counters the applied force by reacting against the propel nut as indicated by reference numeral 611 . Skives 105 on propel nut grip the bore 102 . End cap 401 engages bore 102 as indicated by reference numeral 612 . Put another way, the exterior of the cylindrical barrel of propel nut 104 engages the bore 102 as indicated by numeral 611 . The invention enables the use of a longer threaded stud 103 A which provides a greater range of height adjustment and also stabilizes the leveling device in response to the force F applied to the leveler 109 . Additionally, moment M is absorbed by the engagement of the flange surface 108 with the substrate surface 106 , the engagement of the propel nut 104 with bore 102 as indicated by reference numeral 611 , and the engagement of end cap 401 with bore 102 as indicated by reference numeral 612 .
FIG. 6E is a partial cross-sectional view 600 E of the leveling device having a long threaded stud 103 A where a force F is applied to the foot 109 . FIG. 6E illustrates the stud adjusted so as to provide a different height for the substrate (i.e. a furniture leg). In this way position, the moment M 1 will be larger than the moment M for the position of the FIG. 6D given the same force because the foot 109 has been rotated out of the propel nut 104 and the moment is larger since the force F is applied through a longer radius since the foot has been rotatably moved and translated downwardly.
Still referring to FIG. 6E , long threaded stud 103 A is adjusted to a level position where a significant section of the threaded stud 103 A extends outside the bore 102 past the bottom surface of the substrate 106 . In this position, the leveling device including the threaded nut and the substrate has a greater height. A force F is applied to the leveler. This applied force is counteracted by the end cap 401 and propel nut 104 reacting against bore 102 . Reference numerals 611 and 613 indicate the counteraction of the bore 102 against the propel nut 104 and end cap 401 respectively.
Skives 105 on propel nut grip bore 102 . The bore 102 counters the applied force by supporting the propel nut 104 as indicated by reference numeral 611 . End cap 401 engages bore 102 as indicated by reference numeral 613 . The exterior of the cylindrical barrel of propel nut 104 engages the bore 102 as indicated by numeral 611 .
The invention enables the use of a longer threaded stud 103 A which provides a greater range of adjustment and also stabilizes the leveling device in response to the force F applied to the leveler 109 . Additionally, the moment M 1 is absorbed by the engagement of the flange surface 108 and the substrate surface 106 .
FIG. 7 is a side view 700 of another example of a leveling device. The slab base 2 prong tee nut 701 has a flange 703 with upwardly pointed prongs 702 A and 702 commonly used on the T-nuts.
FIG. 7A is a top view 700 A of FIG. 7 . Intermediate rolled end cap 301 and leveler 109 is flange 703 of a tee nut used in place of a propel nut. Flange 703 includes straight edges in a generally rectangular shape with ends of the flange forming prongs 702 , 702 A.
FIG. 7B is a side view 700 B of another example of the leveling device. A press fit end cap 401 is located at the top of the threaded stud 103 A. A slab base two hole tee nut 707 has a generally rectangularly shaped flange 704 with long straight edges on opposite sides. Tee nut 707 includes apertures for tacking the tee nut to a substrate. The flange 704 of the tee nut extends past the leveler 109 horizontally on both sides. Each of the straight edges of the flange 704 are connected with a rounded arc on each end.
FIG. 7C is a top view 700 C of FIG. 7B . From this view, flange 704 is seen to have a generally rectangular profile with rounded arcs on the shorter ends. Apertures 705 and 706 are located in the flange on opposites of the flange 704 . Flange 704 has two longer straight edges with rounded edges on the shorter sides. The straight line edges of the flange 704 extend past the circular profile of the leveler 109 which is located underneath the flange 704 .
FIG. 7D is side view 700 D of another example of the leveling device. Slab base two tab tee nut 711 has arc shaped wings 708 , 709 that extend in an upward direction 708 , 709 much like a napkin holder. The arc shaped wings of the flange 710 extend in a horizontal direction past the nut 109 A and the leveler 109 .
FIG. 7E is a top view 700 E of FIG. 7D . Flange 710 is seen to have a generally rectangular shaped profile with the extended wings 708 , 709 on flange 710 seen as long straight sides with shorter arc shaped edges at both ends in this view. The extended wings 708 , 709 extend past the outer circumference of the leveler 109 .
FIG. 8 is a perspective view 800 of a desk 801 with a leveler 109 attached to the bottom of a side wall 802 of the desk.
FIG. 8A is a cut-out perspective view of the leveler 109 attached to the bottom of side wall 802 of the desk 801 in FIG. 8 . The threaded stud 103 A is located in a bore 102 in the side wall 802 with end cap 301 located at the top of the threaded stud 103 A near the top of the bore 102 . The propel nut 804 is located in the bore 102 and interengages the threaded stud 103 A. Skive 105 of the propel nut engages the bore 102 . Contact surface 108 of the flange of the propel nut engages the bottom of side wall 802 .
FIG. 8B is a perspective view 800 B of a piece of furniture 801 . Roller 809 is located on the bottom of the side wall 802 .
FIG. 8C is an enlarged cut-away view 800 C from FIG. 8B . Threaded stud 103 A is located in a bore 102 in the cutout 803 of the file cabinet. The outer surface of the top end of the thread stud 303 is located near the top of the bore 102 . Rolled end cap 301 on the cylindrical end of the threaded stud has a snug fit within the bore 102 . Propel nut is located on the threaded stud with skive 105 of the propel nut gripping the bore 102 . Nut 109 A is located on the threaded stud 103 A beneath the flange of the propel nut. Nut 109 A is integral with roller 809 . Roller 809 is located at the bottom of the side wall of the desk. The threaded stud 103 A and the side wall of the desk rests on the roller 809 .
Referring to FIGS. 8-8D , when the furniture is moved, the bore in the substrate, the end caps, the propel nut and the flange of the propel nut absorb the moment applied due to the threaded stud.
LIST OF REFERENCE NUMERALS
100 cross-section view of the prior art leveler of FIG. 1
101 wood, plywood, or pressboard substrate
102 bore or aperture in substrate
103 threads
103 A threaded stud
104 propel nut
105 skive of propel nut
106 bottom surface of wood, plywood, or pressboard substrate
107 flange of propel nut
108 contact surface of flange
109 leveler
109 A nut
109 B outer surface of leveler for engagement with the floor
120 cylindrical end of stud
130 deformation in substrate
200 bottom view of the prior art leveler in substrate
201 cracks in surface of substrate
210 distortions in substrate
300 exploded perspective view of leveler
300 A perspective view of assembled leveler
300 B top view of leveling device
300 C cross sectional view along line 3 C- 3 C
301 rolled end cap
302 seam of rolled end cap
303 top end of stud
304 internal threads of propel nut
315 radius of propel nut joining barrel
320 end cap fit over cylinder in the bore
400 exploded assembly view of leveler
401 press fit end cap
500 exploded assembly view of leveler with shorter propel nut
504 A extended length of propel nut
504 shorter propel nut
600 perspective view of leveler with adjusted position of propel nut
600 A perspective view of leveler with long threaded stud
600 B partial cross-sectional view of leveler in substrate
600 C partial cross-sectional view of leveler in substrate
600 D partial cross-sectional view of leveler with force applied perpendicularly to the leveler
600 E partial cross-sectional view of leveler with force applied perpendicularly to the leveler
601 rolled end cap
601 B support of end cap in plastic substrate
602 seam of rolled end cap
604 propel nut
610 plastic substrate
611 support of propel nut embedded in substrate
612 support of end cap of cylinder end of threaded stud in the bore
613 support of end cap of cylinder end of threaded stud in the bore
700 partial cross section view of propel nut with pointed flanges
700 A end view of propel nut with toothed flanges
700 B partial cross section view of propel nut with extended rectangular flange
700 C view of propel nut with generally rectangular flanges
700 D partial cross section view of propel nut with extended downward directed arc-shaped flange
700 E view of propel nut with extended downward directed arc-shaped flange
701 slab base 2 prong tee nut
702 , 702 A prongs
703 flange of slab base 2 prong tee nut
704 rectangular flange of propel nut
705 , 706 aperture
707 shaft of propel nut with rectangular flange
708 extended wing on flange
709 extended wing on flange
710 flange
711 shaft of propel nut
800 perspective view of side wall of desk using improved leveling device
800 B perspective view of file cabinet using improved leveling device
801 furniture,
802 side wall of furniture
803 cutout of sidewall of furniture
809 roller
F force applied perpendicular to the threaded stud
M-moment
M 1 -moment
Those skilled in the art will realize that the invention has been set forth with particularity by way of example only and that many changes may be made to the invention without departing from the spirit and scope of the appended claims. | An improved leveling device for adjusting the height of a substrate with a leveling device located between the floor and the bottom of the piece of furniture. The leveling device is comprised by a threaded stud which resides in a propel nut. The threaded stud is comprised by a first end, an end cap, and a second end, a leveling surface. The leveling device is inserted into a bore in the bottom of the piece of furniture. The propel nut of the leveling device grips the bore and holds the leveling device in the bore. The oversized end cap with respect to the threaded stud and the propel nut in combination with the bore of the substrate is resistably movable and exerts a force against the bore in the substrate to counter forces exerted against the leveler by the floor when dragging the furniture. | 0 |
This application is a division of application Ser. No. 660,387 filed Feb. 23, 1976, now U.S. Pat. No. 4,065,871.
BACKGROUND OF THE INVENTION
This invention relates to animal traps and more particularly this invention relates to a low impact leghold type animal trap.
Leghold traps have been in use for many years in the fur trapping industry and are wide spread in their application. Depending on the size of the trap, a great variety of animals can be caught, usually without damage to the fur. These traps have recently been widely criticized because of certain aspects which are considered by some people to be inhumane. One of the most important of the disadvantages leading to the charges of inhumanity is the fact that when the jaws clamp shut on the leg of the animal, they do so with considerable force and inflict severe pain.
Interestingly, the basic design of the leghold trap has not changed over the years with new improvements being made generally in the trigger assembly or other components not affecting the operating principle of the trap. See, for example, U.S. Pat. Nos. 833,827, dated Oct. 23, 1906; 1,356,775 dated Oct. 26, 1920; 1,939,190, dated Dec. 12, 1933; and 3,335,517, dated Oct. 15, 1967.
Although there have been improvements to leghold traps over the years, the basic construction remains the same today as it was 100 years ago. Specifically, a pair of jaws pivotally mounted on a base plate are moved upwardly from the set position to the sprung position by spring means urging the jaws together. As already mentioned it has been found that the impact force of the jaws coming together is extremely high and, in fact, unnecessarily high. In order to prove this, a technique was developed at the Laboratories of Arthur D. Little, Inc. for measuring the forces involved in these traps and a measuring apparatus was constructed.
It will be recognized that the behavior of a trap cannot be expressed as a single number. As the trap closes, the geometry varies continuously and the impact force, therefore, varies according to the size of the object between the jaws. Similarly, the clamping force after impact varies with jaw opening. Plotting the force versus the jaw opening accurately defines a trap. As will be discussed more fully hereinbelow, if means could be provided to lessen the impact forces and provide more uniform clamping force at smaller openings of the trap, the standard leghold trap can be made more humane.
Accordingly, it is a primary object of the present invention to provide a leghold type trap which operates in a more humane manner than the prior art traps.
It is another object of the present invention to provide a leghold type trap wherein the clamping force of the jaws is materially reduced at smaller openings.
It is yet another object of the present invention to provide a leghold type trap wherein the impact force of the jaws is reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
This 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 perspective view of a trap according to one embodiment of the present invention;
FIG. 2 is an end view of the trap of FIG. 1;
FIG. 3 is a perspective view of another configuration of a trap according to the first embodiment;
FIG. 4 is a side elevation, partially fragmented, of another configuration of a trap according to the first embodiment;
FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4;
FIG. 6 is a sectional view taken along the line 6--6 of FIG. 4, with the trap in the set position;
FIG. 7 is similar to FIG. 6 but with the trap partially closed;
FIG. 8 is similar to FIGS. 6 and 7 with the jaws in the closed position;
FIG. 9 is a perspective view of a spring and damper means according to a second embodiment of the present invention;
FIG. 10 is a perspective view of a spring and damper means and part of a trap according to another configuration of the second embodiment of the present invention;
FIG. 11 is an end view, partly in section, of a prior art trap with the jaws half closed;
FIG. 12 is an end view, partially in section, of a trap according to another embodiment of the present invention;
FIG. 13 is a curve showing calculated forces against jaw opening of a prior art trap and a trap according to the third embodiment of the present invention;
FIG. 14 is a curve showing the actual forces plotted against jaw opening of the prior art trap and the trap according to the third embodiment of the present invention;
FIG. 15 is a plan view of a trap according to still another embodiment of the present invention with the trap in the set position;
FIG. 16 is a front view of the trap of FIG. 15 with the trap in the set position;
FIG. 17 is a perspective view of the damper means used in the trap of FIG. 15; and
FIG. 18 is a front view of the trap of FIG. 15 in the closed position.
SUMMARY OF THE INVENTION
According to the present invention, an animal trap of the leghold type is provided having a base, a pair of U-shaped coacting jaws swingably mounted on the base, spring means biasing the jaws to a closed position, trigger means for locking the jaws in an open position until released and means for reducing the impact of the jaws when they close without significantly reducing the closing speed or holding power. In one embodiment, an inertial snubber is mounted in such a way as to absorb excess energy from the spring immediately before impact of the jaws. In another embodiment, the jaws are shaped to provide an escapement and the lever or spring riding up the jaws is made to contact the escapement so that as the jaws close a point will be reached whereat the jaws momentarily reverse their direction thereby dissipating excess energy. In another embodiment the shape of the jaws is programmed in such a way that the energy curve will remain fairly constant.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, there is shown a jump trap generally designated by the numeral 10 which has a base 12 having elongated first and second ears 14 and 16 at the ends thereof and a pair of jaws 18 and 20. Jaws 18 and 20 each comprises a pair of substantially parallel spaced legs 22 and 24 and cross-member 26. The legs 22 and 24 terminate in laterally outwardly directed pintles 28 journaled through bores 30 in ears 14 and 16. Affixed to the longitudinal base 12 is a lateral cross-piece 32. Upstanding from cross-piece 32 is leg 34 having pintles 36 journaled through bores 38 in the shank 40 which is integral with the pan 42. Extending upwardly and outwardly from one end of cross-piece 32 is an extension 44 carrying dog 46.
It will be seen that legs 22 are relatively straight extending downwardly from cross-member 26 to pintle 28. In the prior art trap legs 24 would have the same configuration. The last essential member of the trap is a spring which, in the embodiment of FIG. 1, is shown as a jump spring 48 which is in the form of a leaf spring affixed to base 12 at the end 50 which is in the approximity of legs 22. Spring 48 is affixed to base 12 by any suitable means such as rivets or screws 52. Spring 48 terminates at the other end portion in opening or eye 54 the shape of which will be described more fully hereinbelow. It will be recognized, however, that in the prior art traps the eye 54 is generally circular so that when the trap is set with the spring forced into a position against base 12 and the jaws are spread apart and held in place by pan and shank assembly 40, 42 and dog 46 (see FIG. 6), and the trap is released, the end portion of spring 48 carrying eye 54 will move rapidly upwardly and urge legs 24 into the upright and closed position. But, in this embodiment of the present invention, it is noted that legs 24, when together in an upright position and viewed from the end as in FIG. 2, generally conform to an "hour glass" shape. That is, each of the legs 24 has a pintle 28 and then curves outwardly for a short distance at 56, inwardly at 58, outwardly at 60, and inwardly again at 62 to where the substantially straight portion 64 begins. The eye 54 of spring 48 has a longitudinally extending cross-piece 66 extending between legs 24 and terminating in an upwardly extending portion 68.
Thus, in use, the trap is set as already explained and when triggered by an animal, spring 48 moves upwardly with outer wall 70 of eye 54 riding along portion 56 of legs 24 thereby urging the jaws to a closed position. However, when eye 54 reaches the portion 58 of legs 24, the direction of the jaws is suddenly reversed so that they momentarily begin to open again. But, as eye 54 reaches portion 60 of legs 24, the jaws are again urged to a closed position. This momentary opening of the jaws in the middle of their closing travel absorbs or dissipates considerable energy which is essentially unusable energy in terms of the necessary clamping force to hold an animal and diminishes the impact. The loss in closing time caused by this momentary reverse motion is negligible. The direction of travel of jaws, therefore, is, in essence, controlled by an escapement.
Referring to FIG. 3, there is seen another configuration of a trap falling within the definition of the first embodiment of the present invention already described. This trap comprises base 12 and jaws 72 and 74. Each of the jaws has a leg 76 and an opposite leg 78 each journaled by means of pintles 28 into upstanding ears 80 and 82. Cross-piece 32 holds the pan and shank assembly and dog (not shown). It will be seen that legs 76 are substantially straight while legs 78 form a similar escapement to that shown in FIG. 1. Instead of a jump spring as shown in FIG. 1, the configuration of FIG. 3 shows a long spring 84 which is also a leaf spring. Leaf spring 84 has a stationary end 86 and a slidable end 88. End portion 88 has a pair of eyes 90 and 92 separated by a cross-piece 94. The operation of this trap is the same as the operation of the trap of FIG. 1 with end portion 88 of spring 84 moving upwardly when the trap is released and urging the jaws together for the first part of their travel, momentarily apart, and then together again.
Referring now to FIGS. 4 through 8, there is seen another configuration of a trap according to this first embodiment of the invention. In this trap, base 12 is provided with upstanding ears 96 and 98 into which pintles 28 of jaws 100 and 102 are journaled. Cross-piece 32 having upstanding ears 34 and 44 carrying pan and shank assembly 42 and 40, and dog 46, respectively, are the same as previously described.
As shown in FIG. 4, partially fragmented for ease of illustration, a long spring basically similar to that shown in FIG. 3 is used having upper portion 104 and lower portion 106 which, in turn, are fixed to eye members 108 and 110, respectively. Eye member 110 merely contains an enlongated slot to fit over base portion 112 of ear 98. Eye member 108, however, has a pair of eyes 114 and 116 (FIG. 5) to fit over ear portions 118 and 120, respectively (FIGS. 5 and 6). Between eyes 114 and 116 is cross-piece 122.
As can be clearly seen in FIG. 8, the configuration of legs 124 and 126 of jaws 100 and 102, respectively, includes a lower foot portion 128 having substantially parallel linear outer surface 130 and inner surface 132. Moving upwardly from foot portion 128, there is a first intermediate portion 134 projecting inwardly and having a curved outer surface 136 and rectilinear inner surfaces 138 and 140, which can be more easily recognized by reference to FIG. 6. Again moving upwardly, there is second intermediate portion 142 defined by substantially parallel linear outer and inner surfaces 144 and 146, respectively. Finally, there is upper portion 148 which is defined at its outer surface by linear edge 150 and at its inner surface by curved surface 152 which is transformed to linear surface 154, linear surface 154 being substantially parallel to linear surface 150.
For ease in understanding the operation of this trap, attention is directed to FIGS. 6 through 8, and in particular to FIG. 7. In FIG. 6, the trap is shown in its set position with jaws 100 and 102 fully open and held in place by the locking mechanism which comprises the pan 42, shank 40, and dog 46. This, in turn, compresses the spring which is held in position by surface 130 of legs 124 and 126 of the jaws 100 and 102. Considering FIG. 7, when the jaws are released and the spring begins to move upwardly, member 108 moving upwardly and bearing against surface 130 urges the jaws up and toward the closed position. As the member 108 moves to the position shown in phantom in FIG. 7, portion 122 becomes the operative factor and, by bearing against surface 138 and then 140, it reverses the direction of travel of the jaws and urges them slightly more open to the position shown in phantom in FIG. 7. As member 108 continues to rise, it bears against surface 144 to close the jaws and hold them in a closed position as shown in FIG. 8.
Thus, it will be seen that each of the traps shown in FIGS. 1 through 8, while having a slightly different configuration, operates in essentially the same way. It will be appreciated, also, that while these traps are shown and described by reference to particular type of spring, that is, a jump spring or a long spring, the actual type of spring is immaterial and they may be interchanged. In fact, a coil spring type trap having a lever of the type shown in FIG. 15 could be used in this embodiment.
Turning to the next embodiment, attention is directed to FIG. 9 which merely shows a prior art type long spring 154 terminating at either end in an eye 156. This spring when used in the conventional manner is mounted essentially as shown in FIG. 3 but, of course, using the conventionally shaped jaws which will be appreciated by referring to FIG. 11 or to any of the prior art patents cited above. At this point it is important to keep in mind the basic principles underlying the various embodiments of the instant invention. Specifically, it must be understood that a leghold trap must grip a captured animals's leg with sufficient force to prevent escape. A spring strong enough to provide this force, however, liberates considerable energy when the trap is triggered and most of this energy is absorbed by the animal's leg. Thus, it is important to be able to dissipate excess energy harmlessly without compromising the gripping power of the spring. With this in mind, and returning to FIG. 9, there is provided a damper or snubber generally designated by numeral 158 which comprises an inertia arm 160 extending outwardly from a crank 162 rotating in upstanding legs 164. In operation, the trap begins to close in the conventional manner, the jaws being driven together by a leaf spring, either of the long spring or the jump spring type. Before the jaws contact the animal's leg, however, the spring encounters the crank 162. The spring must turn the crank, accelerating inertia arm 160 in order to continue its own motion. Since the arm 160 has higher inertia than the jaws, the spring essentially lags behind the jaws and softly clamps the same shut after they have already closed due to their own momentum.
FIG. 10 shows another form of inertial damper or snubber. In this modification, provision is made in ear 166 which is upstanding from base 12 of the trap for inserting hook means 168 of inertial snubber 170. Again, as the spring rises, it contacts inertial snubber 170 imparting excess energy to it and lagging behind the jaws which close gently and then become clamped by the spring.
Before discussing the next embodiment of the instant invention, it would be helpful to briefly describe certain of the factors involved in the use of a typical leghold trap. For this purpose, a standard Victor number 3 long spring trap was used. It will be appreciated by one skilled in the art that the principles involved apply to any size trap of the leghold type and that this discussion by reference to a number 3 trap is for illustrative purposes only. FIG. 11 shows the geometry of the trap jaws in the standard trap. The expression F = fR/L gives the static clamping force at any opening. The expression F = S tan θ describes the relationship between the jaw angle and the spring force. In these calculations, friction was ignored, as was the minor variation in spring force, since neither factor would have much effect on the basic relationships.
The "standard #3" curve in FIG. 13 shows the results of a series of calculated data points. One sees a drastic increase in force at less than half inch opening. This would be likely to severely injure small animals, while allowing larger ones to escape. Redistributing the spring force in a more reasonable distribution is shown on the second curve of FIG. 13, marked "Modified Jaw #3 Trap." This was arrived at by selecting desired values of F as θ varied. Returning to the formula F = fr/L, L barely varies, and both f and R vary with θ:
f = S tan θ
R = K sin θ
Therefore, varying θ will produce any desired value of F.
Following the above formula, jaws were fabricated as shown in FIG. 12. In this case, jaws 172 and 174 each has a lower portion 176 having a curved outer surface denoted as "C." It will be appreciated, therefore, that as the eye of the spring moves upwardly along surface C urging the jaws closed, θ constantly changes. In the particular example, using a number 3 trap, curved surface C was arcuate. Measurements were then taken on an instrument measuring force in millivolts, the instrument having previously being calibrated so that 1.84 millivolts was equal to 1 pound. Jaw opening was plotted against force for both the standard trap and the trap with the jaws modified as in FIG. 12. The curves are set forth in FIG. 14 it was not possible to take measurements at extremely small jaw openings because of the size of the sensor. It will be seen, however, that the curve for the standard trap is essentially as calculated and shown in FIG. 13 and the curve for the modified jaw trap essentially follows that predicted as in FIG. 13 and, in fact, was somewhat more level. Clearly, therefore, the impact force of the jaws closing, regardless of the distance between the jaws at the time of closing on the leg of an animal, is held relatively constant and at a relatively low level. In a sense, the jaws can be "programmed" to provide any desired force curve.
Turning now to FIG. 15, there will be seen a leghold trap of the coil spring type. This trap is shown with two springs but this embodiment could be used with a single coil spring of the type shown in Montgomery et al. U.S. Pat. No. 3,335,517. This trap which is generally designated by the numeral 178 comprises a base 180 having upstanding ears 182; jaws 184 comprising a pair of substantially parallel spaced legs 186 and 188 terminating in laterally outwardly directed pintles 190 which are journaled through bores in ears 182; and cross-piece 190 carrying pan and shank assembly 192, with the pan partially broken away for clarity of illustration, and dog 194. A generally U-shaped spring mount 196 is mounted on cross-piece 190 and base 180 in such a way that the legs 198 and 200 are aligned transversely of base 180 and equidistant from cross-piece 190. Levers 202 and 204 are mounted to pivot on legs 198 and 200, respectively, of mount 196. Levers 202 and 204 are provided with openings 206 and 208, respectively, which correspond to the eyes 156, for example, of spring 154 shown in FIG. 9. Also mounted on legs 198 and 200 are coil springs 210 and 212 which are joined at their far ends by member 214. At the ends of the coil springs 210 and 212 closest to base 180, end portion 216 and 218 is fixed to the underside of lever 202 and 204, respectively, so that the levers are normally biased in an upward position as shown in FIG. 18. As shown in FIG. 15, on the other hand, the trap is in the set position and the levers are down and the jaws wide open.
To this point, the description of the trap of FIGS. 15 through 18 has been a description of a conventional coil spring leghold trap. But, according to the last embodiment of the present invention, a pair of inertial snubbers or dampers is provided which relies on the mass of the trap itself to provide the inertial damping. The inertial snubber is shown in FIG. 17 and is generally designated by the numeral 220. It comprises a crank portion 222 and an arm portion 224. As will be seen from FIG. 15, snubber 220 is mounted in such a way that crank 222 rides on lever 202 or 204 and is mounted to pivot about the axis provided by members 198 and 200. Arm 224, when the trap is in the set position lays flat on the ground with the weight of the trap itself on top of the same. This can be easily seen in FIG. 16.
Turning to FIG. 18, it will be seen that when the trap is sprung, levers 202 and 204 are urged upwardly in the direction shown by arrows A by springs 210 and 212 thereby urging jaws 184 together. At the same time, however, cranks 222 are contacted by levers 202 and 204 and caused to rotate about pivots 198 and 200, respectively. As cranks 222 rotate, arms 224 move in the direction shown by the arrows labelled B. Since the trap 178 is resting on arms 224, when arms 224 are caused to move as shown by arrows B, the trap itself is displaced upwardly. The mass of the trap 178 causes an inertial dampening of levers 202 and 204 which then lag behind the closing of the jaws 184. Jaws 184 close gently on the animal's leg and then are tightly clamped by levers 202 and 204. An additional advantage of this action is that the upward movement of the complete trap will cause the jaws to close higher up on the animal's leg thereby creating a more positive grip as well as a less painful grip. Additionally, if the animal pulls its leg away from the trap when it is startled, the trap, in essence, follows this action and still grips the animal's leg.
While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. | An animal trap of the leghold type having low impact force is disclosed. The means for lessening the impact force of the jaws when they close takes one of three forms. The first is an inertial snubber. The second is an escapement mechanism. The third is a programmed control of the impact force by changing the shape of the bearing surface of the jaws on which the spring rides. | 0 |
Research and development of the present invention and application have not been Federally-sponsored, and no rights are given under any Federal program.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to dispenser caps of the type intended to discharge viscous products in ribbon or strip-like form.
2. Description of the Related Art Including Information Disclosed Under 37 CFR §§1.97-1.99
The present invention more particularly relates to improvements in the dispenser cap illustrated and described in U.S. Pat. No. 5,044,530 dated Sep. 3, 1991, and issued to co-inventor Gene Stull.
The following additional U.S. patents are cited as being of interest in the field to which the present invention pertains:
U.S. Pat. Nos.:
______________________________________1,895,854 3,108,721 3,216,6303,285,479 3,369,707 3,549,0603,578,223 3,901,410 4,358,0314,646,949 4,754,899 4,842,169______________________________________
Also, reference is made to:
British Pats. Nos. 10,767 and 688,732, and
German Pat. No. 1,203,668
U.S. Pat. No. 1,895,854 discloses a dispenser tube having an apertured cap which is turnable on the tube and wherein an internal plug that is carried on a helical member (29) advances toward or retracts from the aperture as the cap is turned, so as to selectively seal or open the aperture.
U.S. Pat. No. 3,108,721 illustrates a removable valve assembly for a container, having a plug-like valve stem which normally maintains the valve in a closed position. U.S. Pat. Nos. 3,901,410 and 3,549,060 similarly show plug-like tilt valves for selectively sealing off the discharge passages of pressurized aerosol containers.
U.S. Pat. No. 3,578,223 discloses a squeeze bottle having an apertured screw cap and an internal fitment member that is snapped onto and retained by the neck of the bottle. Unscrewing of the cap unseats a sealing peg from the aperture in the cap, to enable dispensing of product.
A somewhat similar construction is shown in U.S. Pat. No. 4,358,031. An apertured screw cap is carried on the neck of a bottle, and an internal fitment member having a sealing plug is receivable in the aperture of the cap.
U.S. Pat. No. 4,646,949 illustrates still another type of screw cap employing a sealing plug that is carried on the base cap or undercap for a dispenser. An aperture in the screw cap is selectively sealed off by the sealing plug when the screw cap is disposed in a lowered, sealing position.
British Patent No. 10,767 discloses an apertured closure cap for the threaded neck of a container, the latter carrying an upstanding stopper plug of flattened configuration. The plug is turnably mounted in a transverse wall that extends across the neck. As the cap is unscrewed, it backs away from the plug thereby to unseal the aperture in the cap.
British Patent No. 688,732 discloses a screw cap construction wherein an axially shiftable apertured closure cap is selectively sealed by a plug that is pressed into the neck of a container and held captive therein. When the cap is unscrewed, the plug is withdrawn from the aperture, enabling discharge of the contents of the container to occur.
German Pat. No. 1,203,668 discloses a twist cap construction employing a stopper peg that is carried by an insert which is force fitted into the neck of a container or tube, and an apertured closure cap that can be moved between sealing and discharging positions. The discharging position corresponds to a raised condition of the closure cap wherein its aperture is uncovered.
Also, U.S. Pat. Nos. 3,216,630; 4,754,899 and 4,842,169 disclose twist cap constructions of the type having stopper pegs of cylindrical configuration. The pegs in each case provide a seal with corresponding cylindrical walls of the discharge openings in the respective twist cap when the latter are placed in sealing positions.
In prior caps having round discharge passages, where the product being dispensed is relatively viscous as in the case of ketchup or mustard, such product emerges in the shape of an elongate, thin bead. In use, the container is inverted and squeezed while the opening of the twist cap is positioned over or applied to the underlying food.
As noted above in connection with U.S. Pat. No. 1,895,854 and British Pat. No. 10,767, efforts have been made to provide cap structures with elongated or oblong openings, in which the product is discharged as a flat ribbon, as opposed to a bead of essentially round or oval cross section. Such a ribbon shape has been considered desirable for use with mustard and ketchup, since it results in a more uniform application, and improved adhesion to the particular food to which such mustard or ketchup is being applied.
However, most prior attempts to achieve ribbon-type discharge characteristics have met with little commercial success. For example, in U.S. Pat. Nos. 3,285,479 and 3,369,707 the twist caps that are disclosed are provided with slit-like openings in their ends, in which are received blade-like sealing members. The blade-like members are fixedly mounted on the undercap or base cap. In U.S. Pat. No. '707, as the twist cap is unscrewed it rides up cam tracks provided on the base cap. The blade-like sealing member occupies the slit in the twist cap. During such unscrewing the upper end portion of the blade-like sealing member is forcibly twisted and deformed, and eventually separates from the walls of the slit to provide a discharge passage for the product. Following use, the consumer reseats the twist cap by turning it in a screwing-on direction, with the blade-like sealing member purportedly being restored to its initial planar shape, and re-establishing its position occupying the slit in the twist cap.
In U.S. Pat. No. 3,285,479 the arrangement is similar, except that the twist cap is not raised by means of a cam track on the base cap. Instead, when the twist cap is turned in either direction, the blade-like sealing member becomes deformed as it is engaged by the inner conical surface of the twist cap and the latter is in turn, cammed upwardly by such engagement. Portions of the walls of the slit become disengaged from the blade-like sealing member and thus enable product discharge. Re-sealing is accomplished by merely pushing downwardly on the twist cap. As this is done, the blade-like sealing member tends to restore the twist cap to its original circumferential position, and the walls of the slit slide over the upper end of the blade-like sealing member, to re-establish the seal.
A number of specific problems have occurred with dispensers of the type involving deformable stopper blades as described above. In particular, it is considered difficult to fabricate a solid sealing member in the form of a flat blade having sufficient resiliency so as to not take a "set", especially following an extended period of use. In addition, attempts to make a plastic blade relatively stiff often resulted in the blade cracking or breaking during use, as opposed to merely flexing, as was desired. In the event of such breakage, the sealing function of the dispenser was completely lost, and there was the possibility of plastic fragments finding their way into the dispensed product. This was particularly troublesome where the substance being discharged was a food such as mustard, ketchup or other creamy substance, such as dressings and the like.
Even where breakage of the blade did not occur, smooth operation of the cap was difficult to attain. In particular, the use of the blade as a cam to shift the cap, as in U.S. Pat. No. '479, caused undue stresses on the blade, and it is believed that the design parameters inherent in prior blade type sealing caps did not lend themselves toward adaptation to a smooth and reliable operating mechanism for a dispensing cap.
As noted above, the present invention involves improvements in the ribbon-type dispenser cap construction of Stull U.S. Pat. No. 5,044,530. While the devices disclosed in this patent have been found to be smooth and reliable in operation, efforts to reduce cost and assembly time are always considered of extreme importance. This patented cap involved basically three separate components, namely the cap body, the closure cap, and as a separate piece, the stopper blade. It was considered that if one component could be eliminated as a separate molded piece, considerable cost savings could be realized. Of course, additional criteria had to be met, namely that any resultant construction have the inherent reliability, safety from contamination, and ease of use of the patented device.
SUMMARY OF THE INVENTION
Accordingly it is an object of the present invention to provide a novel and improved essentially two-piece ribbon-type dispenser cap construction which is extremely simple in its structure and especially low cost in terms of molding, and assembly time.
Yet another object of the invention is to provide an improved dispenser cap construction as above set forth, which provides relatively wide passageways for product flow, thus circumventing potential problems with clogging, poor flow rates for viscous materials, and the like.
Still another object of the invention is to provide an improved dispenser cap as above characterized, which requires a considerably less volume of plastic than many of the prior art devices, thereby saving on material costs.
Yet another object of the invention is to provide an improved dispenser cap in accordance with the foregoing, which is both rugged and reliable in operation, and not susceptible to malfunction.
Still another object of the invention is to provide an improved dispenser cap as outlined above, wherein there is virtually eliminated the possibility of malfunctioning of a type which might result in plastic fragments inadvertently finding their way into the product being dispensed.
A further object of the invention is to provide an improved dispenser cap as above characterized, which can be quickly and inexpensively assembled, largely by automated capping equipment.
The above objects are accomplished by a dispensing cap construction for containers, comprising in combination a cap body and means for attaching the cap body to a container neck, the cap body having a discharge spout portion, and a closure cap turnably carried by the cap body and overlying the spout portion. The closure cap has a non-round orifice, and a stopper blade is located in the closure cap and receivable in the orifice so as to close off the orifice. Resilient means are provided, comprising a pair of oppositely-disposed spaced-apart, resilient support legs connected with the stopper blade and mounting the latter on the spout portion, the resilient means retaining the stopper blade against outward axial movement with respect to the spout portion of the cap body while simultaneously enabling limited rotary movement of the stopper blade with the closure cap as the latter is shifted axially outward on the cap body to thereby effect removal of the stopper blade from the orifice.
The arrangement is such that, in a preferred embodiment, the legs are spaced a sufficient distance so as to permit them to twist or deform slightly as the stopper blade twists with unscrewing movement of the closure cap. It has been found that support legs constructed in accordance with the invention, do not take a "set" to any appreciable extent. Reliable alignment of the stopper blade is maintained at all times, regardless of the open or closed position of the closure cap.
In a preferred form, solely two keying ribs are positioned adjacent the walls of an orifice which is generally oblong or slit-like. The ribs are positioned to guide the blade especially during closing movement of the closure cap, the ribs functioning to engage opposite sides of the blade and insure smooth turning of the blade and alignment with the walls of the orifice.
Other features and advantages will hereinafter appear.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, illustrating a preferred embodiment of the invention:
FIG. 1 is a top plan view of the ribbon-type dispenser cap construction of the present invention, showing the closure cap and stopper blade occupying their closed or sealing positions.
FIG. 2 is a side view, partly in elevation and partly in axial section, taken on the line 2--2 of FIG. 1.
FIG. 3 is a bottom plan view of the closure cap per se, of the dispenser cap construction of FIGS. 1 and 2.
FIG. 4 is a top plan view of the cap body of the dispenser cap construction of FIGS. 1 and 2.
FIG. 5 is a bottom plan view similar to FIG. 3, except showing the closure cap rotated from the position of FIG. 3, as it would appear from the underside, occupying its open, discharging position, and
FIG. 6 is a fragmentary top plan view similar to FIG. 1, except showing the closure cap and stopper blade disposed in their open, discharging positions, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIGS. 1 and 2 there is illustrated a dispenser cap construction generally designated by the numeral 10, including a cap body 12 having a depending skirt 14 with internal threads 16 of usual construction, adapted to mate with corresponding external threads on the neck of a container (not shown). The cap body 12 has a transverse top wall 18, and a spout portion 20 extending upwardly from the top wall 18. The spout portion 20 has a bore or discharge passage 22, Pig. 4, which is preferably of cylindrical configuration. Disposed on the upper surface of the transverse top wall 18 are oppositely disposed cam tracks 24, and at the upper ends of each track 24 there is a stop shoulder 26, one of which is shown in FIG. 2 and both of which are shown in FIG. 4. The spout portion 20 is provided with external threads 28.
Carried on the cap body is a closure cap 30. The closure cap 30 has a pair of cam follower lugs 32 on its underside, FIGS. 3 and 5, adapted to ride up the cam tracks 24 as the closure cap 30 is turned in an unscrewing (counterclockwise) direction as viewed from the top, FIG. 1. The closure cap 30 is provided with internal threads 34 which cooperate with the threads 28 on the spout portion 20, and which function to pull the closure cap 30 axially downward in FIG. 2 when the closure cap 30 is turned in a screwing down direction (clockwise) in FIG. 1.
There is a narrow annular clearance space between the spout portion 20 and the inner surface of the closure cap 30, the clearance space being designated 36. An external sealing bead 38 is provided on the spout portion 20, to prevent the contents of the container from entering the annular space 36. The bead 38 slidingly engages the inner cylindrical surface of the closure cap 30 when the latter is moved between the closed, sealing position illustrated in solid outline in FIG. 2, and the raised, discharging position illustrated in dotted outline, in FIG. 2.
The closure cap 30 has a discharge spout 40 containing a discharge orifice 42. Cooperable means are provided on the exterior surface of the spout portion 20 and on the inner surface of the closure cap 30, to yieldably retain the latter in its open or raised position. In accomplishing the retention, the cap body 12 has a pair of oppositely-disposed outstanding positioning lugs 44, FIG. 4, and there are cooperable camming lugs 46, FIGS. 3 and 5, on the inside of the closure cap 30. When the closure cap 30 is turned in an unscrewing direction, counterclockwise in FIG. 1 or clockwise in either FIG. 3 or FIG. 5, the lugs 44 ride up the camming lugs 46 and come to rest against shoulders 48 which are located at the ends of the camming lugs 46. The lugs 44 are rounded sufficiently so that the shoulders 48 can by-pass the lugs 44 when the user applies sufficient force in a screwing down direction, clockwise as viewed in FIG. 1 or counterclockwise in either FIG. 3 or FIG. 5.
In accordance with the present invention there is provided a novel and improved structural combination for selectively opening or sealing off the discharge orifice 42 of the closure cap 30 in response to turning of the latter with respect to the cap body 12. In accomplishing the sealing function, the the discharge orifice 42 has a non-round, or oblong discharge configuration shown particularly in FIGS. 3, 5 and 6, and there is provided a substantially flat stopper blade 50 having a width in FIG. 2, which exceeds its height in this figure. Disposed at opposite ends of the blade 50 are depending, divergent, resilient and yieldable support legs 52, which extend to the periphery of the bore 22 of the spout portion 20. The legs 52 are relatively thin, being of a thickness which is commensurate with the thickness of the stopper blade 50. The legs are flexible and stretchable in a direction transverse to their lengths. Each leg 52 has two portions, an upper portion 54 whose outermost surface is generally parallel to the axis of the closure cap 30, and a lower portion 56 which is convergent toward the axis of the closure cap 30 and which is of reduced cross section with respect to that of the upper portion 54. The innermost edges of each leg are convergent as shown, and together with the stopper blade 50 and the lip of the spout portion 20, form a trapezoidal-shaped opening 58 when viewed from the side, FIG. 2, which provides a relatively large clearance space through which product being discharged can flow.
As shown in FIGS. 2 and 4, the innermost edges of the legs 52 merge into the cylindrical wall of the bore 22 of the spout portion 20, being substantially flush therewith.
Further in accordance with the present invention, there are provided novel vertical guide ribs 60 on the underside of the closure cap 30 and adjacent the discharge orifice 42 thereof, the guide ribs 60 being substantially co-extensive with one another. One rib 60 is disposed on a side wall of the orifice 42 and nearer one end thereof, whereas the other rib 60 is disposed on the other side wall of the orifice 42 and nearer the other end thereof.
The guide ribs 60 engage the opposite faces of the stopper blade 50 when the closure cap 30 is disposed in its lowered, sealing position as shown in FIG. 1, and as shown in solid outline in FIG. 2. When the closure cap 30 is turned in an unscrewing direction, counterclockwise in FIG. 1, the walls of the discharge orifice 42, having been in engagement with the stopper blade 50, cause it to turn initially only, with the closure cap 30. The absence of ribs on the opposite wall of the discharge orifice 42 directly across from each rib 60 enables the closure cap to ultimately turn by a greater extent than the stopper blade 50 immediately after the initial unscrewing movement has occurred, thereby requiring less turning of the blade 50 than would otherwise be the case were the blade 50 keyed to the closure cap 30 more or less continuously as in the constructions disclosed in Stull U.S. Pat. No. 5,044,530 above identified. As a consequence, the stopper blade 50 turns through an angle which is less than that ultimately experienced by the closure cap 30, such that the parts eventually assume the relative positions shown in FIG. 6. Stated differently, in a fully unscrewed or open position of the closure cap 30, wherein the cam lugs 32 engage the stop shoulders 26, the closure cap 30 and its orifice 42 have turned through a greater angle than the stopper blade 50, by an amount indicated by the angle "X" in FIG. 6. FIG. 4 shows in dotted outline, the position of the stopper blade 50 when twisted, corresponding to a discharging condition of the dispenser cap wherein the closure cap 30 has been raised to the dotted outline position in FIG. 2.
The effect of the reduced turning required on the part of the stopper blade 50 has been found to contribute significantly to the successful operation of the dispenser cap construction 10. In particular, the amount of flexing of the support legs 52 that is required as occasioned by the turning of the stopper blade 50, is correspondingly reduced. The reduction in flexure has two important advantages. It markedly increases the reliability of the dispenser cap since the legs 52 are not likely to break from repeated, excessive stretching. Second, the reduced flexure minimizes the tendency for the legs 52 to take a "set", as was often the case in prior devices where a plastic component was subjected to repeated stretching or prolonged elastic deformation to a predetermined state or configuration. As a consequence, reliability has been found to be excellent, with no noticeable tendency for the legs 52 to buckle or bend, or otherwise experience any tendency to fail.
The particular arrangement of the ribs 60 has been found to contribute to the proper guidance of the stopper blade 50 when the closure cap 30 is turned toward a closing position. Because each rib 60 has no counterpart (rib) on the opposite wall of the discharge orifice 42, there is realized increased space between the stopper blade 50 and the walls of the discharge orifice 42, through which product can more easily flow.
Also, with the disclosed construction, the inclusion of the lugs 44, 46 has been found to be desirable from the standpoint of eliminating any tendency for the resilience of the support legs 52 acting through the stopper blade 50, to inadvertently cause backing off (i.e. toward closing) of the closure cap 30 from its fully open position.
In a preferred form of the invention, there is provided on the underside of the cap body, a keying recess designated 62 in FIG. 2, by which the cap body 12 can be oriented to a particular rotary position on suitable automatic capping equipment (not shown). This same capping equipment can utilize the oblong configuration of the closure cap orifice 42 during assembly, so that the closure cap 30 can be pressed onto the cap body 12 in the proper manner and without the need for manual positioning or guidance. During such pressing on, the threads 28 and 34 by-pass one another, in a manner known per se in the dispenser cap art.
From the above it can be seen that we have provided a novel and improved dispenser cap construction which is both simple in its structure, being in a preferred form, constituted of only two separate molded components, and reliable in operation. Relatively high flow rates are achievable by the unique disposition and configuration of the guide ribs 60, without sacrifice of reliability in assuring alignment between the stopper blade 50 and the walls of the discharge orifice 42 as the closure cap is closed.
The arrangement of two support legs 52 for the stopper blade has been found to provide the needed support therefor while still enabling the blade to turn a limited extent with initial unscrewing movement of the closure cap. Potential problems with the legs 52 taking a "set", or with inadvertent breakage of the legs from repeated opening and closing, are considered to be completely overcome. Also, by virtue of the relatively small mass or volume of plastic represented by the thin stopper blade 50 and support lugs 52, there is realized a savings in the amount of plastic material required, and a consequent savings in manufacturing expense. Also, the impact on the environment is lessened, because of the reduced bulk represented by the article after it has been discarded.
Finally, the dispenser cap of the invention can be adapted for use not only with foods as noted above, but also with other viscous substances, including chemicals, specifically adhesives or glues.
The disclosed ribbon-type dispenser cap construction is thus seen to represent a distinct advance and improvement in the field of closures for hand-held dispensers.
Variations and modifications are possible without departing from the spirit of the invention.
Each and every one of the appended claims defines an aspect of the invention which is separate and distinct from all others, and accordingly it is intended that each claim be treated in this manner when examined in the light of the prior art devices in any determination of novelty or validity. | A dispensing cap construction for containers includes a cap body for attachment to a container neck, the cap body having a discharge spout portion, and a closure cap turnably carried by the cap body and overlying the spout portion. The closure cap has a non-round orifice, and a stopper blade located in the closure cap and receivable in the orifice so as to close off the same. Resilient oppositely-disposed spaced-apart support legs are connected with the stopper blade and mount the latter on the spout portion. The resilient legs retain the stopper blade against outward axial movement with respect to the spout portion of the cap body while simultaneously enabling limited rotary movement of the stopper blade with the closure cap as the latter is shifted axially outward on the cap body, to thereby effect removal of the stopper blade from the orifice. | 1 |
[0001] The present application is a continuation of co-pending application Ser. No. 09/828,1365 filed on Apr. 10, 2001, and for which priority is claimed under 35 U.S.C. §120, the entire contents of which are hereby incorporated by reference. The present application also claims priority upon U.S. Provisional Patent Application. Ser. No. 60/197,677, filed Apr. 17, 2000, the entirety of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention is directed toward the field of digital television signal meta data generation, and more particularly to the non-uniform issuance of certain tables included within such meta data.
BACKGROUND OF THE INVENTION
[0003] It is known for a digital television (DTV) signal to include meta data representing information about the contents of the events, e.g. programs, movies, sports games, etc. contained in the DTV signal. For a terrestrially broadcast DTV signal, the Advanced Television Standards Committee (ATSC) has promulgated the A/65 Standard that defines such meta data. The A/65 standard refers to such meta data as program and system information protocol (PSIP) data.
[0004] The PSIP type of meta data is issued periodically. Data of greater importance in the meta data hierarchy is inserted into the DTV signal more frequently than data of lower importance.
[0005] In general, in this art it is desired to maximize the amount of available bandwidth that can be allocated to the transmission of the DTV program content. Unfortunately, meta data consumes bandwidth that otherwise could be used to transmit the corresponding DTV program content. But such meta data is a prerequisite to an A/65 compliant DTV signal, hence it cannot be eliminated to recover bandwidth.
[0006] It is a problem to reconcile the contradictory design criteria of maximizing bandwidth allocated to DTV program content and providing sufficient meta data to ensure compliance with the A/65 standard.
SUMMARY OF THE INVENTION
[0007] The invention is, in part, a solution to the problem of how to insert the least amount possible of meta data into the DTV signal and yet still achieve an A/65 compliant DTV signal. In other words, the invention is, in part, a recognition that it is desirable to insert meta data into the DTV signal as infrequently as possible.
[0008] The invention is, also in part, a recognition that: the A/65 standard establishes fixed frequencies of table output for some of the program and system information protocol (PSIP) data tables, e.g., such as the Master Guide Table (MGT), the Virtual Channel Table (VCT) and the System Time Table (STT), but not for some others; and such unfixed output intervals afford opportunities to lessen meta data output thereby reducing bandwidth consumption in the form of PSIP meta data without sacrificing compliance with the A/65 standard.
[0009] The invention provides, in part, a method to determine issuance intervals for like types of tables, respectively, in a digital television packet stream having a plurality of different types of tables that do not have issuance intervals set by a governing standard. Such a method comprises: setting issuance intervals for like ones of the non-governed tables, respectively, to be non-uniform. Such non-uniform issuance intervals can be determined as a function of at least one of an amount of time in the future to which the table corresponds and a degree of probable interest to a viewer. Further, such non-uniform issuance intervals can be weighted so that an issuance interval for a table corresponding to a time nearer the present is smaller than an issuance interval corresponding to a time further in the future.
[0010] Examples of meta data PSIP tables that can benefit from the method according to the invention include extended text tables (ETTs) and event information tables (EITs).
[0011] Each issuance interval between any two instances of an i th table can be determined according to the following equation:
[0000] interval( i th table)=root_time+(increment_time)* i
[0000] where interval(i th table) is the interval between any two instances of the i th table, root_time is a predetermined interval for the table corresponding most closely in time to the present, increment time is a non-zero scalar and i is a non-zero integer.
[0012] The invention, also in part, provides a program and system information protocol (PSIP) generator to generate tables for a digital television system packet stream, the generator comprising: an interface to receive at least one issuance parameter for like tables that do not all have an issue interval assigned by a governing standard; and a non-uniform interval calculation unit to determine non-uniform issuance intervals for unassigned-interval-ones of said like tables based upon said at least one issuance parameter. Such a PSIP generator embodies the method according to the invention, e.g., as described herein.
[0013] The invention, also in part, provides a processor-readable article of manufacture having embodied thereon software comprising a plurality of code segments to cause a processor to perform the method according to the invention.
[0014] According to an aspect of the invention, there is provided an apparatus for generating at least one table in a broadcast environment, the apparatus comprising: a generator to generate an event information table (EIT) and an extended text table (ETT), the ETT having program guide information for an n-hour span and having a transmission interval, the ETT having a transmission interval and having program description information according to the EIT, wherein the transmission interval of the EIT is shorter than the transmission interval of the ETT.
[0015] According to an aspect of the invention, there is provided a method for generating at least one table in a broadcast environment, the method comprising: generating an event information table (EIT) and an extended text table (ETT), the ETT having program guide information for an n-hour span and having a transmission interval, the ETT having a transmission interval and having program description information according to the EIT, wherein the transmission interval of the EIT is shorter than the transmission interval of the ETT.
[0016] According to an aspect of the invention, there is provided a data structure for generating at least one table in a broadcast environment, the structure comprising: an event information table (EIT) having program guide information for an n-hour span and having a transmission interval; and an extended text table (ETT) having a transmission interval and having program description information according to the EIT, wherein the transmission interval of the EIT is shorter than the transmission interval of the ETT.
[0017] Advantages of the present invention will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] 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 do not limit the present invention.
[0019] FIG. 1 is a block diagram of a PSIP generator according to the invention in the context of typical inputs to it and outputs from it.
[0020] FIG. 2 is an image of a dialog window within a screen of a graphical user interface (GUI) generated by the PSIP data generator according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] FIG. 1 is a block diagram of a program and system information protocol (PSIP) data generator according to the invention in the context of system 100 that can produce an Advanced Television Standards Committee (ATSC), standard A/65, compliant digital television (DTV) signal. The system 100 of FIG. 1 includes: a PSIP generator 102 according to the invention; sources of data upon which the PSIP generator operates, such as a source 108 of listing service data, a source 110 of traffic system data and a source 112 of other data; a multiplexer 114 to incorporate the PSIP data from the PSIP generator 102 into an A/65-compliant DTV signal; and a source 116 of audio data, video data, etc.
[0022] In FIG. 1 , the PSIP generator 102 includes an interface unit 104 and a non-uniform interval calculation unit 106 .
[0023] The PSIP generator 102 according to the invention can be implemented by adapting a well known PSIP generator according to the discussion herein. An example of a known PSIP generator is the PSIP BUILDER PRO brand of PSIP generator manufactured and sold by TRIVENI DIGITAL INC. The PSIP BUILDER PRO itself is based upon a programmed PC having a Pentium type of processor using the MICROSOFT WINDOWS NT4.0 operating system. The software can be written in the Java language. The ether blocks of FIG. 1 correspond to known technology.
[0024] In FIG. 1 , the invention has been depicted in the context of a digital television broadcast such as a terrestrial broadcast, and more particularly one that is compliant with the Advanced Television Standards Committee (ATSC), where each event is a program, and the schedule data is PSIP data. However, the invention is readily applicable to any television format, e.g., analog terrestrial, analog cable, digital cable, satellite, etc., for which an electronic schedule is maintained and corresponding data is sent to a receiver for the purpose of presenting an electronic program guide (EPG) to a viewer.
[0025] The units 104 and 106 within the PSIP generator 102 do not necessarily correspond to discrete hardware units. Rather, the units 102 and 104 can represent functional units corresponding to program segments of the software that can embody the invention.
[0026] The interface unit 104 can generate a graphical user interface (GUI) that operates to receive at least one issuance parameter for like PSIP tables (e.g., ETTs or EITs) that do not all have an issue interval assigned by the A/65 standard. Such an interface will be described in more detail below with regard to FIG. 2 . The non-uniform interval calculation unit 106 is operable to determine non-uniform issuance intervals for ones of the like PSIP tables that do not have an assigned interval, based upon the issuance parameter(s) received via the interface unit 104 .
[0027] FIG. 2 is an example image of a dialog window 200 (a GUI) that can be generated by the interface unit 104 according to the invention. In FIG. 2 , the dialog window 200 can include: a Cycle Time Settings tab 202 ; a Miscellaneous Settings tab 204 ; a FTP Periodic Update Controls tab 206 ; an “Apply Settings” button 226 ; a “Defaults” button 228 ; a “Refresh” button 230 ; and a “Close” button 232 . The position of the cursor can be indicated via the reverse highlighting 234 . The Cycle Time Settings tab 202 can include a “Cycle Times (in seconds) for EITs:” region 208 , a “Cycle Times (in seconds) for PSIP Tables:” region 210 , a “Cycle Times (in seconds) for PSI Tables:” region 212 and a “Cycle Times (in seconds) for ETTs,” region 214 .
[0028] It is well known that EITs carry program schedule information including program title information and program start information. Each EIT covers a three-hour time span. ETTs carry text messages associated with the EITs, e.g., program description information for an EIT.
[0029] In FIG. 2 , the “Cycle Times (in seconds) for EITs:” region 208 of the dialog window 200 can include: a box 216 in which a user can enter a fixed interval for the EIT 0 table; a box 218 in which a user can enter an increment for the EIT k , table; and a box 220 in which a user can enter a maximum number of EIT tables that are to be sent. Usually, the number entered in box 220 will be far smaller than the maximum number of EIT tables permitted by the A/65 standard.
[0030] Also, in FIG. 2 . the “Cycle Times (in seconds) for ETTs:” region 214 can include: a box 222 in which a user can enter a fixed interval for the ETT 0 table; and a box 224 in which a user can enter an increment for the ETT k table.
[0031] The non-uniform interval calculation unit 106 can receive the values in the boxes 216 , 218 , 220 , 222 and 224 from the regions 208 and 214 , respectively, and use them to determine the non-uniform issuance intervals of, e.g., the EIT and ETT tables. Further discussion of the operation of the unit 106 is couched in a particular non-limiting example, for simplicity.
[0032] The A/65 standard recommends a time interval for outputting the zeroith Event Information Table (EIT), i.e., EIT 0 , but provides no guidelines regarding EIT 1 through EIT 128 . For the Rating Region Table (RRT), the A/65 standard recommends a value only for the output frequency of RRT 1 . And no recommendation is made regarding the output frequencies of any of the Extended Text Tables (ETTs).
[0033] Under the A/65 standard, it is left to the discretion of the operator of a PSIP data generation system to select the frequency of table output for the unmentioned tables. The operator could specify an entry for each group of tables, but that would be burdensome because it would require a total of over 500 entries. A simple solution to the problem of unspecified output frequencies would be to set each type of table to the same output frequency, but that creates a problem in that the guidelines for bandwidth specified by the A/65 standard would be exceeded.
[0034] A further consideration to solve the problem, namely of how to insert the least amount possible of meta data into the DTV signal and yet still achieve an A/65 compliant DTV signal, is: How closely in time to the present moment does each table relate? That is, table types such as the EIT describe event information up to two weeks into the future. A user of an electronic program guide that receives such table types will typically want to view event information concerning only the next 24-48 hours. Users typically do not look farther into the future than this because (at least in part) the event schedule information two weeks into the future is much more likely to change than is event schedule information concerning the next 24-48 hours, i.e., the farther into the future, the less reliable the event information becomes.
[0035] Care must be exercised so as not to set the intervals to be too infrequent. This is because the DTV receiver can become stalled waiting for a table to arrive. If the DTV receiver is stalled for 0.5 seconds, a user might not notice or object if she did. But such a delay of, e.g., 4-5 seconds probably would be noticed by, and probably would annoy, the user. This reinforces the need to set short intervals for near term events because users are likely to want to display EPG information about them.
[0036] Again, the invention, in part, provides an interface unit 104 that defines parameters that the non-uniform interval calculation unit 106 then can use to generate the time intervals between tables of the same type. Typically (but not necessarily) the function performed by the unit 108 will be linear, e.g., with a defined start interval (the root_time) and an increment interval (increment_time). For example, if the user desires EIT 0 to be output every half second (root_time) with each succeeding EIT 1 to be output 0.25 seconds less frequently than the preceding EIT, namely EIT F1 , the user would enter 0.5 seconds as the root_time in box 216 and 0.25 seconds as the increment_time in box 218 . The function for each table EIT-i interval would then be:
[0037] Time between any two instances of table:
=root time+(increment_time*i) =0.5 sec+(0.25 sec*i)
For example, EIT 12 can be output every 0.5 sec+(0.25 sec*12)=3.5 seconds, which is less frequent than EIT 0 . Obviously, other examples are possible, e.g., the increment_time for each of different-groups of like tables can be set.
[0040] A similar calculation for ETTs can be performed by the unit 106 .
[0041] The invention has at least the following advantages: 1) it provides an easy way of entering the interval times for the tables: 2) it defines the interval times for like tables that are not all fixed to a constant interval; and 3) it provides an interval function that increases the interval for tables that represent information further out in time.
[0042] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | An apparatus, method and data structure for generating at least one table in a broadcast environment, are provided. The apparatus includes a generator to generate an event Information table (EIT) and an extended text table (ETT). The ETT has program guide information for an n-hour span and has a transmission interval. The ETT has a transmission interval and program description information according to the EIT. The transmission interval of the EIT is shorter than the transmission interval of the ETT. | 7 |
BACKGROUND
This invention relates to automated server replication.
The popularity of the World Wide Web as a communications medium lies in the richness of its information content and ease of use. Information in this medium exists as objects in a widely distributed collection of internetworked servers, each object uniquely addressable by its own Uniform Resource Locator (URL). The proliferation of commercial applications on the World Wide Web brings with it an increasing number of users making ever-increasing numbers of requests for web content. The problems of latency and bandwidth considerations manifest themselves in delay and lost information.
Network architects respond using an array of solutions, one of which is the server farm. This involves the use of multiple web servers with identical content, or the segmentation based upon functionality. For example, two servers for web functions, two for File Transfer Protocol (FTP), two as a database, and so forth. The use of multiple servers solves one problem at the expense of creating another. If there are multiple servers, how does the end user locate a particular web site? Presently, names and Universal Resource Locator (URLs) are resolved into unique single addresses by a Domain Name Service (DNS) residing in a DNS server. DNS servers maintain a list of domain names cross referenced to individual Internet Protocol (IP) addresses. However, if multiple web servers or server farms are used, a modified version of DNS service is used. A common approach to this problem is to modify the DNS system to be aware of a one-to-many mapping of names-to-IP-addresses. Thus, the DNS will return an IP address that comes from a list of possible IP addresses that correspond to a particular web object. Thus, from one moment to the next, a DNS query will resolve to different IP addresses. In this example, the modified DNS decides which IP address to return based on how busy each of the servers is.
In current network management systems, there are various methods of detecting and monitoring the load across a server or a server farm. One system uses a load capacity detection agent to monitor the load across a server or a server farm. In this system, when the load detection agent detects that a server farm, for example, is experiencing excess load, the agent notifies a system administrator of the system. The system administrator may decide to manually take action to either reduce the load across the server farm, or alternatively, increase the available load capacity by adding a server to the server farm. Generally, the system administrator adds a server by manually identifying an additional available server, and then modifying the entries in the load management system to include the IP address of the recently-added content server.
SUMMARY
In general, in one aspect, the invention provides a method and apparatus, including a computer program apparatus, implementing techniques for detecting a change in demand for server resources across a load-bearing system having one or more content servers hosting identical content, the load-bearing system being connected to a network of content servers; and automatically modifying the number of content servers on the load-bearing system in response to the change in demand.
Each content server on the network may be categorized as active or idle. The hosted content may be assigned a priority level, and a number defining a maximum number of content servers on the load-bearing system. A content server may be added to the load-bearing system if the change in demand is greater than a pre-configured threshold and the number of content servers on the load-bearing system is less than a maximum number assigned to the hosted content. The number of content servers may be modified by selecting an available content server on the network; loading hosted content onto the selected content server; and adding the selected content server to the load-bearing system. All of the content servers on the load-bearing system including the selected content server host identical content. The available content server having the lowest priority level, the highest available load capacity, or the least number of active sessions may be selected.
The hosted content may be assigned a number defining a minimum number of content servers on the load-bearing system. A content server may be removed from the load-bearing system if the change in demand is greater than a pre-configured threshold and the number of content servers on the load-bearing system is greater than a minimum number assigned to the hosted content. The content server having the highest available load capacity or the least number of active sessions may be removed.
Embodiments may have one or more of the following advantages. The invention uses scripting, or other software techniques, to automate the addition or removal of a content server from a load-bearing system. Automating the addition and removal of content servers gives, for example, a web hosting operation a way to manipulate server resources between high-activity servers and low-activity servers without requiring any user intervention. In particular, the invention serves the needs of “seasonal” or “spiky” web applications, such as tax preparation services or Superbowl-related web sites, which experience a tremendous increase in the number of hits at specific times of the year.
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
FIGS. 1 a - 1 d are block diagrams illustrating an internetwork topology including an network of content servers and a management server.
FIG. 2 is a flowchart of a process for automatically modifying the number of content servers on a load-bearing system.
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
Referring to FIGS. 1 a - 1 d , an exemplary internetwork 100 includes a network of servers 102 connected to a network of clients 104 through the Internet 106 . The network of servers 102 includes a management server 108 and a group of content servers 110 .
The content servers 110 are nodes on the network 102 that perform the actual serving of content, for example, Web pages or FTP files. Although only nine content servers 110 are shown in FIGS. 1 a through 1 d , it will be understood that any number of content servers may be connected to the network 102 . Each content server 110 is capable of receiving queries from clients, doing substantially all the processing necessary to formulate responses to the queries, and providing these responses to the clients. Web servers, for example, respond to requests from clients (e.g., through browser software) for access to files and data. Other types of servers allow clients to share access to network devices, such as shared printers or disk storage.
In one exemplary commercial setting, each content server 110 is a managed node on the network 102 maintained by a network operator, such as Genuity Inc. of Woburn, Mass. By the term “managed node”, it is meant that each content server 110 runs a management process that allows another computer to query the managed node for information. For example, Simple Network Management Protocol (SNMP) describes how a computer formats a message to send to the managed node. Software on the managed node, called an SNMP agent (not shown), examines SNMP messages it receives, and responds accordingly. Each SNMP agent maintains a local database of variables that describe the state of the content server 110 and may, optionally, affect its operation. Each SNMP agent's local database includes, but need not be limited to the following: the number of packets and bytes sent and received from the Internet 106 , the number of broadcasts, the current output queue size, the current transaction rate, the current processor utilization, and the current disk utilization.
Content servers 110 are the systems which store information that may be accessed using web browser software such as Netscape Communicator® and Microsoft's Internet Explorer®. Content servers transmit their information in response to receiving a message of a format specified by Hyper Text Transfer Protocol (HTTP). The format of the server's response is also specified by HTTP, and is understood by web browser software.
Network management on the network 102 can be done from management servers, an example of which is shown as management server 108 , which are general-purpose computers running management software. The management server 108 interacts with the SNMP agents in the content servers 110 using the SNMP protocol. This protocol allows the management server 108 to query the state of an agent's local variables, and change them if necessary. For example, the management server 108 can issue commands and get responses that allow the management server 108 to monitor the resources available (i.e., available load capacity) on each content server 110 , and express them in a way that enables the content servers 110 to be categorized as active or idle. In one example, the management server 108 only considers the CPU resource, and neglects all others. In other implementations, the management server 108 uses a more complex combination of considerations, with load metrics ranging from the instantaneous CPU utilization and IO queue length, through to a linear combination of CPU, memory and IO queue lengths. The management server 108 can also modify network routing tables, and change the status of network links and devices. The collection of all possible variables available via SNMP is given in a data structure called the Management Information Base (MIB), which is formally defined in the Internet Engineering Task Force (IETF) Request For Comment (RFC) 1213 . The IETF is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and smooth operation of the Internet—it is open to any individual.
The management server 108 also houses several other software components, which include in one implementation, an image manager 116 , and a content storage system 118 . In the illustrated examples on FIGS. 1 a - 1 d , a single server implements the software components of the management server 108 . However, it should be noted that two or more servers connected to the network 102 may implement the software components.
The router 114 uses any one of a number of dynamic routing algorithms (e.g., distance vector routing and link state routing) to decide where to send packets addressed to a particular IP address; for example, how to get to a particular content server which are all distinguished based on their assigned IP address. Dynamic routing algorithms change their routing decisions in response to changes in the topology of the network 102 . A set of files is stored in the content storage system 118 . Each file contains content data, applications and all the necessary software required to implement a web site presence on the Internet 106 . Each file can be loaded onto a content server 110 by the image manager 116 . In one implementation, the image manager 116 maintains a table (shown below) that includes, for each file, a priority level, a minimum number and a maximum number of content servers 110 that can be used to implement the web site. The priority level indicates to the management server 108 the relative importance—to the network operator, Genuity Inc., for example—of implementating a particular web site in situations in which several web sites are vying for limited server capacity. In one implementation, a five-point scale is used to designate a priority level: “highest”, “high”, “medium”, “low” and “lowest”. Generally, the higher the priority level assigned to a file, the more server resources (up to the maximum number of content servers 110 identified in the table) are allocated to implement the web site. By default, content servers 110 that are idle are assigned a “lowest” priority level. When a file having a “highest” priority level is loaded onto a content server 110 that is idle, for example, the priority level of the content server 110 changes from “lowest” to “highest”.
Assume, for example, that three files—file “A”, file “B”, and file “C”—are stored in the content storage system 118 . The second, third and fourth table entries are populated with the following data:
File Priority Level Min. Number Max. Number A highest 1 7 B medium 1 3 C low 1 3
Initially, each file is loaded and run on one or more content servers 110 , indicated in dashed lines in FIG. 1 a as load-bearing system A 120 , load-bearing system B 122 , and load-bearing system C 124 . If a load-bearing system, such as load-bearing system A 120 , has multiple content servers 110 , the load on the system is distributed using one of the following schemes: (1) a load-sharing scheme; (2) a load-balancing scheme; or (3) a load-leveling scheme. Generally, content servers 110 in a load-sharing system that utilizes the load-sharing scheme are viewed in binary. That is, the server is either idle or busy, and load may only be placed on idle servers. Load-balancing schemes attempt to ensure that the load on each content server 110 in the system is within a small degree of the load present on every other content server in the system. Load-leveling schemes can be viewed as the middle ground between the load-sharing and load-balancing schemes. Rather than trying to obtain an even distribution across the system, or utilizing only the content servers 110 that are idle, the load-leveling scheme distributes load in a manner that minimizes congestion.
Referring to FIG. 2 , a process 200 residing in the management server 108 periodically checks ( 202 ) the available load capacity on each load-bearing system. In one implementation, the process 200 polls each content server 110 in a load-bearing system to determine its available load capacity.
If the process 200 detects ( 204 ) that the load on the load-bearing system B 122 , for example, is greater than a preconfigured threshold level (i.e., there is insufficient aggregate available load capacity), the process then determines ( 206 ) whether the number of content servers 110 in the load-bearing system B 122 is less than the maximum number that may be allocated to that system. If so, the process 200 will add a content server 110 to the load-bearing system B 122 if one is available. By use of the term “available”, it is meant that the content server 110 is idle and may be added to a load-bearing system, or alternatively, the content server has a lower priority level and may be removed from a particular load-bearing system and allocated to a different load-bearing system. For example, as shown in FIG. 1 b , if the load-bearing system C 124 is implemented by a single content server 124 a , the content server 124 a is not available for re-allocation to either of the other two load-bearing systems 120 and 122 , because the network operator has designated in the table that at least one content server 110 in the network 102 must be allocated to the load-bearing system C 124 .
The process 200 first polls all of the content servers 110 on the network 102 to determine ( 210 ) if there is an available content server 110 on the network 102 . If none of the content servers 110 are available, the process 200 logs and signals the event ( 208 ) to the network operator maintaining the network 102 . Otherwise, the process 200 selects ( 212 ) one of the available content servers for addition to the load-bearing system B 122 . If there are multiple available content servers 110 , the process 200 will typically select one that is idle for addition to the load-bearing system B 122 . However, if all of the available content servers 110 on the network 102 are active, as shown in FIG. 1 c , the process 200 makes the selection as follows:
(1) If there is only one available content server 110 , the process 200 selects that content server 110 . (2) If there are multiple available content servers 110 , the process 200 selects the content server 110 having the lowest priority level. (3) If there are multiple available content servers 110 having the lowest priority level, the process 200 polls each of those content servers 110 to determine which content server 110 has the highest available load capacity and selects that content server 110 . Alternatively, the process 200 polls each of those content servers 110 to determine which content server 110 has the least number of running processes in progress (called “active sessions”) and selects that content server 110 .
Once the selection is made, say, for example, the process 200 selects the content server having an IP address of “128.11.234.59” 124 b in the load-bearing system C 124 , as shown in FIG. 1 c , the process 200 can be configured to immediately stop all future client queries directed to the load-bearing system C 124 from being sent to the selected content server 124 b for processing. The process 200 can also be configured to wait until all of the active sessions on the selected content server 124 b have been terminated before removing that content server 124 b from the load-bearing system C 124 . Once removed, the process 200 retrieves the file “B” from the content storage system 118 and uses the image manager 116 to load ( 214 ) it onto the selected content server 124 b . Referring to FIG. 1 d , the process 200 then starts the selected content server 124 b having the recently-loaded file “B”, and modifies the DNS system to add ( 216 ) the content server having an IP address of “128.11.234.59” 124 b to the load-bearing system B 122 . Thereafter, when a client requests a service by entering in a web browser the URL for the web site implemented by the load-bearing system B 122 , the request can be directed to the content server 124 b.
Referring to FIG. 1 c , 1 f the process 200 detects ( 218 ) that the load on the load-bearing system B 122 , for example, is less than a preconfigured threshold level, the process 200 then determines ( 220 ) whether the number of content servers 110 in the load-bearing system B 122 is more than the minimum number that may be allocated to that system 122 . If so, the process 200 may select ( 222 ) a content server 110 from the load-bearing system B 122 for removal if the aggregate available load capacity of the load-bearing system B, the historical demand for services implemented by the load-bearing system B, as well as damping considerations, among others, warrants removal of a content server. The process 200 selects a content server for removal much in the same manner described above. That is, the selection may be made by polling each of the content servers 110 in the load-bearing system B 122 to determine which content server 110 has the highest available load capacity and selecting that content server 110 . Alternatively, the selection may be made by polling each of those content servers 110 to determine which content server 110 has the least number of active sessions and selecting that content server 110 . The process 200 can be configured to wait until all of the active sessions on the selected content server 110 have been terminated before removing ( 224 ) that content server 110 from the load-bearing system B 122 , and categorizing it as idle.
Other embodiments are within the scope of the following claims. | Methods and apparatus for detecting a change in demand for server resources across a load-bearing system having one or more content servers hosting identical content, the load-bearing system being connected to a network of content servers; and automatically modifying the number of content servers on the load-bearing system in response to the change in demand. | 7 |
COPYRIGHT NOTICE AND AUTHORIZATION
[0001] This patent document contains material which is subject to copyright protection.
[0002] (C) Copyright 2007. Chevron U.S.A. Inc. AH rights reserved.
[0003] With respect to this material which is subject to copyright protection. The owner, Chevron U.S.A. Inc., has no objection to the facsimile reproduction by any one of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records of any country, but otherwise reserves all rights whatsoever.
FIELD OF THE INVENTION
[0004] The present invention relates to the use of steam for increasing oil recovery in fields characterized by a high viscosity crude oil.
BACKGROUND OF THE INVENTION
[0005] Steam flooding is a method of increasing oil recovery from an oil field where the oil has a high viscosity. The high viscosity slows or prevents flow of oil thus inhibiting its recovery. Steam flooding greatly reduces the viscosity of the crude oil so that it can now flow from the reservoir into the production wells.
[0006] Typically, in steam flood operations the steam generators are not completely automated. Additionally, there is no steam flood operation where the latent heat targets are used for the control of steam generation or steam distribution, and there is no place where steam generation and distribution controls are integrated, in summary, a need exists for complete integration and automation of the controls of steam generation and distribution driven by heat management design. Throughout the life of a steam flood project, steam generation and distribution need to be optimized to ensure that each injection well rate (and cyclic heat delivered to the reservoir to promote production) proceeds along the trajectory necessary to provide the appropriate latent heat to each part of the reservoir. Executing this reliably and efficiently, day in and day out, will increase the probability that a steam flood project achieves its planned operational efficiency and production.
[0007] This invention overcomes the above-described shortcomings of known methods and systems.
SUMMARY OF THE INVENTION
[0008] In one aspect, the present invention is a method for determining a steam injection schedule for a set of subsurface formation regions (or patterns) of an oil field, the method including the steps of: determining a thermal maturity for each subsurface region of the set; calculating a latent heat target for each subsurface region according to the determined thermal maturity therefore; calculating a steam injection target tor each subsurface region according to the calculated latent heat target therefore; determining the availability of steam for injection to the subsurface regions; and calculating a steam injection schedule for each subsurface region according to the determined steam availability and calculated steam injection targets for all subsurface regions of the set.
[0009] Another aspect of the invention provides a system for determining a steam injection schedule for a set of subsurface formation regions of an oil field, the system including: a CPU; a memory operatively connected to the CPU, the memory containing a program adapted to be executed by the CPU; the program configured and adapted for: determining a thermal maturity for each subsurface region of the set; calculating a latent heat target for each subsurface region according to the determined thermal maturity therefore; calculating a steam injection target for each subsurface region according to the calculated latent heat target therefore; determining the availability of steam for injection to the subsurface regions; and calculating a steam injection schedule for each subsurface region according to the determined steam availability and calculated steam injection targets for all subsurface regions of the set. So that the above recited features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof that are illustrated in the appended drawings. 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic context diagram showing the environment of the invention and its relationship to other systems.
[0011] FIGS. 2-3 depict a schematic system level 0 data flow diagram of one embodiment of the invention and show the major process and logical data flow between the major processes.
[0012] FIGS. 4-10 depict a schematic level 1 or 2 data flow diagram (a first or second decomposition of one process in the level 0 data flow diagram in FIG. 2 , or others) and show the processes and logical data flow between the processes of the Determine Thermal Maturity process 1.0.
[0013] FIG. 11 depicts a schematic level 1 data flow diagram of the processes and logical data flow between the processes of the Determine Latent Heat Target process 2.0.
[0014] FIG. 12 depicts an exemplary constant steam Injection schedule.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] Overview
[0016] The major components (also interchangeably called aspects, subsystems, modules, functions, services) of the system and method of the invention, and examples of advantages they provide, are described below with reference to the figures. For figures including process/means blocks, each block, separately of in combination, is alternatively computer implemented, computer assisted, and/or human implemented. Computer implementation optionally includes one or more conventional general purpose computers having a processor, memory, storage, input devices, output devices and/or conventional networking devices, protocols, and/or conventional client-server hardware and software. Where any block or combination of blocks is computer implemented, it is done optionally by conventional means, whereby one skilled in the art of computer implementation could utilize conventional algorithms, components, and devices to implement the requirements and design of the invention provided herein. However, the invention also includes any new, unconventional implementation means.
[0017] The System
[0018] FIG. 1 is a schematic context diagram showing the environment of the invention and its relationship to other systems. Steam System Optimizer Process 100 interacts with several other systems or entities. Several processes/entities receive data from and send data to Steam System Optimizer Process 100 . Steaming schedule data passes from Steam System Optimizer Process 100 to Master Work Schedule Process 130 so that work tasks necessary to implement the steaming schedule can be scheduled. Steaming schedule data passes from Steam System Optimizer Process 100 to De-Watering Management Process 120 so that de-watering work tasks necessary to implement the steaming schedule can be scheduled, Steaming schedule data passes from Steam System Optimizer Process 100 to Surface Facility Development processes 160 so that surface facility work tasks necessary to implement the steaming schedule can be scheduled. These same external systems send results back to Steam System Optimizer Process 100 for calibration to keep it synchronized with actual field results.
[0019] Several processes/entities provide data to Steam System Optimizer Process 100 . Subsurface region development data passes from Subsurface region Development (or Pattern Development) Management Process 150 to Steam System Optimizer Process 100 so that it can be taken into account in optimizing the steam system. Generator Management data passes from Generator Management Processes ( Steam Generators) 110 to Steam System Optimizer Process 100 so that it can be taken into account in optimizing the steam system. Generator management data passes from Well-Logging Processes 140 to Steam System Optimizer Process 100 so that it can be taken into account in optimizing the steam system. These same external systems will accept schedule information from Steam System Optimizer Process 100 .
[0020] FIGS. 2-3 depict a schematic block system level 0 data, flow diagram of one embodiment of the invention and show the major process and logical data flow between the major processes. Determine Thermal Maturity process 205 passes output to Thermal Maturity File 240 . The output is an indication of thermally mature or not.
[0021] Determine Latent Heat Target process 210 retrieves the Determine Thermal Maturity process 205 output as formatted data from Thermal Maturity File 240 and passes its own output to Latent Heat Target File 245 . The output from Determine Latent Heat Process 210 is a value having units of BTU′s, or other units measuring of heat, to be delivered to the subsurface region. Determine Steam. Injection Target process 220 retrieves Determine Latent Heat Target process 210 output as formatted data from Latent Heat Target File 245 and passes its own output to Steam Injection Target File 250 . The output is a target barrels of steam to be delivered to each subsurface region.
[0022] Determine Available Steam process 227 retrieves Determine Steam Injection Target process 220 output as formatted data from Steam Injection Target File 250 and passes its own output to Available Steam File 255 , The output is a table or other structured or unstructured data indicating steam availability over a time period of interest for each subsurface region of interest. Determine Steam Injection Schedule process 225 retrieves Determine Available Steam process 227 output as formatted data from Available Steam File 255 and passes its own output to Steam Injection Schedule File 260 . The output is a steam injection schedule. Given a latent heat target for one or more subsurface regions, available steam, along with other system constraints. Determine Steam Injection Schedule process 225 prepares a steaming schedule for a predetermined time period, e.g., number of days, weeks, or months. Various methods can be used to prepare a schedule based on pre-determined criteria, e.g., desired time to reach thermal maturity for each subsurface region. Methods of preparing a cyclic steaming schedule are described in U.S. Pat. No. 6,446,721, entitled System and method for scheduling cyclic steaming of wells, assigned to Chevron U.S.A. Inc., which is incorporated herein by reference in its entirety.: Methods of preparing a non-cyclic steaming schedule are described in U.S. Pat. No. 5,174,377, entitled Method for optimizing steam flood performance, assigned to Chevron Research and Technology Company, which is incorporated herein by reference In its entirety.
[0023] Execute Steam Injection Schedule process 230 retrieves Determine Steam Injection Schedule process 223 output as formatted data from Steam Injection Schedule 260 and passes its own output to Steam Schedule Execution File 265 . The output is a list or schedule of tasks and operating procedures necessary to execute the steam schedule. Monitor Steam Injection process 235 retrieves Execute Steam Injection Schedule process 230 output as formatted data from Steam Schedule Execution Schedule 265 and passes its own output to Monitor Steam Injection File 270 . The output is a historical report of steam delivered to each subsurface region and each well within a subsurface region. Determine Steam Deficiency/Excess process 270 retrieves Monitor Steam Injection process 235 output as formatted data from Monitor Steam Injection File 270 . The output indicates any variances between the steam scheduled to be delivered and the steam actually delivered.
[0024] FIGS. 4-10 depict a schematic level 1 data flow diagram (a first decomposition of one process in the level 0 data flow diagram in FIG. 2 ) and show the processes and logical data flow between the processes of the Determine Thermal Maturity process 205 .
[0025] FIG. 4 a depicts a preferred embodiment of the overall Determine Thermal Maturity Process 205 . First (process 400 ) determine In steps 405 and 415 the reservoir type, i.e., if a single or multi-zone reservoir (step 405 ) and whether the reservoir is flat or dipping (step 415 ), This output will be used (step 417 ) in assigning weighting to thermal maturity indicators in step 460 .
[0026] In FIG. 4 b, then (process 407 ) retrieve the latest neutron density (“ND”). Neutron density is dimensionless. If the ND is less than a predetermined threshold (step 430 ), then get temperature data (step 440 ). If the ND is not less, then the pre-determined threshold then this indicates more liquid is present and there is no steam chest, thus the subsurface region is not thermally mature (step 435 ). The pre-determined threshold temperature is determined, e.g., by identifying the saturation temperature of steam at the prevailing reservoir pressure. The temperature is retrieved via a query to a temperature survey database.
[0027] After getting the temperature data from well logging data (step 440 ), determine if the temperature is above a pre-determined threshold (step 445 ). If not, then this indicates pores are filled with air and there is no steam chest, thus the subsurface region is not thermally mature (step 450 ), If the temperature is above a pre-determined threshold (step 445 ), then the subsurface region potentially thermally mature and the indicator status should be identified (step 455 ) and combined (step 460 ) by averaging them with appropriate weights. “Indicator status” refers to the indicator supporting the pattern being mature or immature.
[0028] Then determine if the combined indicator value is at least at a pre-determined threshold (step 465 ). If not, men this indicates there is not enough evidence of a steam chest and the subsurface region is at most of mixed maturity (step 470 ). If yes, the there is sufficient evidence of thermal maturity (step 475 ).
[0029] FIG. 5 provides a preferred embodiment of a first deconstruction view determining the combined indicator value (step 455 )—showing specific indicators. FIGS. 6-11 provide a preferred embodiment of a second deconstruction view of the individual indicators in FIG. 5 . Five indicator categories are shown in FIG. 5 . The first one listed is to determine if high temperature and low saturation or flat temperature for thick sands (step 515 ). If yes, this indicates thermal maturity 505 . IF not then determine if low temperature and high saturation or not flat temperature for thick sands (step 520 ). If yes, then this indicates a mixed maturity 510 . The determination of whether there is a high temperature and low saturation is by user specified thresholds. “High”temperature means higher than the user specified threshold, “Low” saturation means lower than the user specified threshold.
[0030] The next listed indicator is to determine if the flow line or wellhead temperature is elevated (step 525 ). This is determined by measuring the temperature of flowing fluid at the wellhead. An “elevated” wellhead temperature in this context means higher than the user specified threshold. If yes, this indicates thermal maturity 505 . If not, this indicates mixed thermal maturity 510 . The next listed indicator is/to determine if production has peaked (step 530 ). If yes. this indicates thermal maturity 505 . If not, this Indicates mixed thermal maturity 510 , The next listed indicator is to determine if case vent rates are high (step 540 ). This is determined by user specified thresholds. “High” case vent rates in this context means higher than the user specified threshold. If yes, this Indicates thermal maturity 505 . If not, this indicates mixed thermal maturity 510 . The next listed indicator is to determine if a steam chest has developed (step 545 ). This is determined by an earth model. A “developed” steam chest means presence of steam at the top of the zone of consideration. If yes, this indicates thermal maturity 505 . If not, then check if there are pockets in the steam chest (step 550 ). If not, this indicates mixed thermal maturity 510 .
[0031] FIG. 6 depicts in one embodiment a further decomposition 600 of the Determine if Flow line or Wellhead Temperature is Elevated indicator 525 ( FIG. 5 ). This is applicable in single-reservoir projects. First, for a given subsurface region retrieve the flow line temperature for associated wells and determine if it is high (step 605 ), This is determined by user specified thresholds, A “high” flow line temperature in this context means higher than specified threshold. If not, this indicates not thermal mature (step 610 ). If yes, validate whether the temperature can be used by determining If the well has not been recently steamed (step 615 ). If it has been recently steamed, then the temperature data cannot be used to indicate thermal maturity, so there is not a clear indicator of thermal maturity (step 620 ). If not recently steamed, determine if the flow rate is high (step 625 ), i.e., is it adequate when compared to the predicted production rate. If the flow rate is high (step 625 ), then this indicates thermal maturity (step 630 ). If not, there is no clear indicator of thermal maturity (step 625 ). As a follow-up it is recommended to look for FOP (fluid over pump) conditions.
[0032] FIG. 7 depicts in one embodiment a further decomposition 700 of the Determine if Casing Vent Rates are High indicator 540 ( FIG. 5 ). This is applicable in single-reservoir projects. If the casing vent rate is not high when compared to the well baseline value (step 705 ), then there is no clear indicator of thermal maturity (step 710 ). If the easing vent rate is high, then this indicates thermal maturity (step 715 ).
[0033] FIG. 8 depicts in one embodiment a further decomposition 800 of the Determine if the Production has Peaked indicator 530 ( FIG. 5 ). First, determine if the barrels of production per day per well is declining (step 805 ). This is determined by applying change point analysis to monthly production data. If no, then there is no clear indicator of thermal maturity (step 810 ), If it is declining (step 805 ), then determine if the recommended heat is being provided (step 815 ), i.e., enough heat to reach thermal maturity. “Recommended heat” in this context means the targeted pattern level injection rate. If no, then low heat may be the reason production is low and there is no clear indicator of thermal maturity (step 820 ). If the recommended heat is being provided (step 815 ), then validate the heat measurement to ensure the correct physical conditions are being met by determining if the injectors are in critical flow (step 825 ). If no, then there is not enough steam being injected and there is no clear indicator of thermal maturity (step 830 ). If the injectors are in critical flow (step 825 ), this indicates thermal maturity (step 835 ). This is determined by comparing the pressures upstream and downstream of the orifices. “Critical” flow in this context means fluid is flowing at sonic velocity.
[0034] FIG. 9 depicts in one embodiment a further decomposition 900 of the step of determining if high temperature and low saturation or flat temperature for thick sands (step 515 ), First, determine if the target sands are thick (step 905 ). This is determined by interpretation of geologic parameters. “Thick” target sands In this context means thicker than a user specified threshold. If yes, then determine if the temperature is greater than a pre-determined threshold temperature (step 910 ), typically measured in an observation well. This is determined by see above. The predetermined threshold temperature is determined by user specified parameters. If not, then this measurement is not valid and there is no clear indicator of a steam chest and thermal maturity (step 915 ). If yes, then this indicates thermal maturity (step 920 ). The predetermined threshold temperature is derived from the known reservoir pressure at the observation well.
[0035] FIG. 10 depicts in one embodiment a further decomposition 1000 of the Determine if a Steam Chest has Developed indicator 545 ( FIG. 5 ). Firsts determine if an Earth Model, e.g., GOCAD™ brand Earth Model is available (step 1010 ), i.e., whether an earth model is available that can accept the thermal data. If yes, then read the Earth Model output and determine if visualizations provide evidence of a steam chest (step 1020 ). This is determined, e.g., by model observation. If not, there is no clear indicator of a steam chest and thermal maturity (step 1030 ). If yes, then this indicates thermal maturity (step 1040 ).
[0036] FIG. 11 depicts a schematic level 1 data flow diagram of the processes and logical dataflow between the processes of the Determine Latent Heat Target process 210 . The status of either thermally mature on not thermally mature is retrieved by Determine Latent Heat Target process 210 . This can be Implemented via a thermally mature variable for each subsurface region which is either set or not set, i.e., set being a value of 1 and indicating thermal maturity, and not set being a value of 0 indicating not thermally mature. If the thermally mature variable is set, control is passed to Heat Maintenance Rate Calculator process 1120 . Otherwise, control is passed to Neumann Rate Calculator process 1110 . The output from Determine Latent Heat Process 210 is a value having units of BTU's, or other units measuring of heat, to be delivered to the subsurface region.
[0037] Determine Steam Injection Target process 220 ( FIG. 2 .) is a calculation. The heat in BTU's from Determine Latent Heat Process 210 is divided by the amount of heat per barrel of steam to determine the needed barrels of steam. Steam quality will vary so this calculation must be updated periodically.
[0038] Constraints used in determining Steam Injection Schedule 225 ( FIG. 3 ) include fresh water availability, distribution system limits, well injection limits, steam generator capacity and maintenance schedules, cyclic steam rig availability and well availability for cyclic steaming. Distribution system limits include steam delivery limits of the distribution system header, well choke size or control valve setting, and pipe sizes.
[0039] FIG. 12 depicts an exemplary constant steam schedule 1200 . Each well is identified in No. column 1210 arid name column 1215 . The steam rate column 1220 gives steam rates, e.g., barrels per day or other suitable expression of unit volume per unit time. Steam quality column 1225 gives the steam quality in, e.g., percent vapor. Valve/Choke settings 1230 indicates the size, e.g., diameter, of a variable opening at the well head. This setting must typically be changed manually if a change is desired. The date 1235 the new steaming schedule 1200 is to take effect is given, or alternatively, each well may have a separate date field.
[0040] Other Implementations
[0041] Other embodiments of the present invention and its Individual components will become readily apparent to those skilled in the art from the foregoing detailed description. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the spirit and the scope of the present invention. Accordingly, the drawings and detailed description are to he regarded as illustrative in nature and not as restrictive. It is therefore not intended that the invention be limited except as indicated by the appended claims. | The invention includes a method for determining a steam injection schedule for a set of subsurface formation subsurface regions of an oil field, the method including the steps of determining a thermal maturity for each subsurface region of the set; calculating a latent beat target for each subsurface region according to the determined thermal maturity therefore; calculating a steam injection target for each subsurface region according to the calculated latent heat target therefore; determining the availability of steam for injection to the subsurface regions; and calculating a steam injection schedule for each subsurface region according to the determined steam availability and calculated steam injection targets for all subsurface regions of the set. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application Ser. No. 10/938,275 filed Sep. 9, 2004 entitled Photochromic Polyurethane Laminate, which claims the benefit of priority from U.S. Provisional Application Ser. No. 60/501,820 filed Sep. 9, 2003 entitled Photochromic Laminate; and U.S. Provisional Application Ser. No. 60/501,819 filed Sep. 9, 2003 entitled Photochromic Film And Method Of Manufacture, all of which are hereby incorporated herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a photochromic laminate that can be applied to polymeric surfaces or can be used by itself as a photochromic element. The invention also relates to a photochromic laminate that is capable of withstanding high temperatures and can be incorporated into plastic lenses by means of injection molding. The invention further relates to a photochromic laminate that is excellent in both control of thickness and surface smoothness of the photochromic layer, and thereof exhibits uniform darkness at the activated state.
[0004] 2. Description of the Related Art
[0005] Photochromic articles, particularly photochromic plastic materials for optical applications, have been the subject of considerable attention. In particular, photochromic ophthalmic plastic lenses have been investigated because of the weight advantage and impact resistance they offer over glass lenses. Moreover, photochromic transparencies, e.g. window sheets, for vehicles such as cars, boats and airplanes, have been of interest because of the potential safety features that such transparencies offer.
[0006] The use of polycarbonate lenses, particularly in the United States, is widespread. The demand for sunglasses that are impact resistant has increased as a result of extensive outdoor activity. Materials such as polycarbonate have not historically been considered optimal hosts for photochromic dyes due to slow activation rate, slow fading (bleaching) rate, and low activation intensity.
[0007] Nonetheless, there are several existing methods to incorporate photochromic properties into lenses made from materials such as polycarbonate. One method involves applying to the surface of a lens a coating containing dissolved photochromic compounds. For example, Japanese Patent Application 3-269507 discloses applying a thermoset polyurethane coating containing photochromic compounds on the surface of a lens. U.S. Pat. No. 6,150,430 also discloses a photochromic polyurethane coating for lenses.
[0008] Another method involves coating a lens with a base coating. An imbibing process described in U.K. Pat. No. 2,174,711 or U.S. Pat. No. 4,968,454 is used to imbibe a solution containing photochromic compounds into the base coating material. The most commonly used base material is polyurethane.
[0009] However, the two methods described above, which involve coating the lens after it is molded, have significant shortcomings. For example, typically a coating of about 25 μm or more is needed to incorporate a sufficient quantity of photochromic compounds into the base in order to provide the desired light blocking quality when the compounds are activated. This relatively thick coating is not suited for application on the surface of a segmented, multi-focal lens because an unacceptable segment line and coating thickness nonuniformity around the segment line are produced, and the desirable smooth surface quality is affected.
[0010] Lenses made from plastic materials such as polycarbonate are produced by an injection molding process and insert (also known as in-mold decoration) injection molding is used to incorporate photochromic properties into the lenses. Insert injection molding is a process whereby a composition is injection molded onto an insert in the mold cavity. For example, as disclosed in commonly assigned U.S. Pat. No. 6,328,446, a photochromic laminate is first placed inside a mold cavity. Polycarbonate lens material is next injected into the cavity and fused to the back of the photochromic laminate, producing a photochromic polycarbonate lens. Because the photochromic function is provided by a thin photochromic layer in the laminate, it is practical to make photochromic polycarbonate lenses with any kind of surface curvature by the insert injection molding method.
[0011] Transparent resin laminates with photochromic properties have been disclosed in many patents and publications, for example, Japanese Patent Applications 61-276882, 63-178193, 4-358145, and 9-001716; U.S. Pat. No. 4,889,413; U.S. Patent Publication No. 2002-0197484; and WO 02/093235. The most commonly used structure is a photochromic polyurethane host layer bonded between two transparent resin sheets. Although the use of polyurethane as a photochromic host material is well known, photochromic polyurethane laminates designed especially for making photochromic polycarbonate lenses through the insert injection molding method are unique.
[0012] Problems associated with conventional insert injection molding techniques in the manufacture of photochromic lens are polyurethane bleeding and poor replication of segment lines. “Bleeding” occurs from the deformation of the polyurethane layer during processing. In particular, bleeding occurs when the polyurethane layer melts and escapes from its position between the two transparent sheets of the laminate during the injection molding process. The inventors have discovered that bleeding most frequently results from an excess amount of polyurethane and from using too soft a material. The inventors have also discovered that poor replication of segment lines occurs when the layer of polyurethane is too thick and movement of the laminate occurs as pressure from the mold is applied.
[0013] In order to prevent the bleeding problem, it is preferred to have the polyurethane cross-linked. However, cross-linked polyurethane, once made, is difficult to be laminated between transparent resin sheets. A convenient method to incorporate cross-linked polyurethane is to start with a liquid polyurethane system such as the one described in U.S. Patent Publication No. 2002-0197484. To make the laminate efficiently, a web coat-laminate line such as the one described in Japan Patent Laid Open 2002-196103, is usually used. The state of the art coating equipment is capable of coating a uniform layer of liquid polyurethane mixture. However, this layer will only be partially solidified (or cured) at the moment of in-line lamination. Any possible surface defects of resin sheet and lamination rollers are easily transferred to the soft polyurethane layer during lamination. The most often seen defects in the polyurethane layer include thickness un-evenness across the web and thin spots due to uneven pressure at lamination or improper handling. In order to have the polyurethane layer firm enough to withstand the necessary pressure during lamination, it needs to be cured for a certain amount of time, which slows down the processing or renders the continues web coating-laminating impossible.
[0014] Therefore, the need exists to overcome the problems and shortcomings associated with existing polyurethane laminates having photochromic properties and methods of making these laminates.
BRIEF SUMMARY OF THE INVENTION
[0015] The need and shortcomings of the existing laminates and methods of manufacturing these laminates are met by the polyurethane laminate and method in accordance with the present invention.
[0016] It is an object of the present invention to provide a transparent photochromic polyurethane laminate that has improved thickness uniformity and surface smoothness, so that the darkness or light transmission at the activated state is uniform.
[0017] It is another object of the present invention to provide a photochromic polyurethane laminate that exhibits dimensional stability under high temperature and high pressure, so that it can be used to produce a plastic photochromic lens though an insert injection molding process.
[0018] The objects are achieved by the transparent photochromic polyurethane laminate in accordance with the present invention. One embodiment of the present invention comprises a polyurethane layer including photochromic compounds having first and second sides, a front transparent resin sheet is bonded to the first side of the polyurethane photochromic layer, and a back transparent resin sheet is bonded to the second side of the polyurethane photochromic layer. The front and back transparent resin sheets may be bonded to the polyurethane layer with or without additional adhesive such as epoxies and the acrylate types. The front and back transparent resin sheets are preferably made of the same material as the lens base. That is, if the lens base material is polycarbonate, it is preferred to have polycarbonate resin sheets bonded to the polyurethane photochromic layer. If the lens base material is cellulose acetate butyrate, then it is preferred to have cellulose acetate butyrate resin sheets bonded to the polyurethane photochromic layer. Any clear, transparent plastic resin may be used for the base and resin sheets, for example, polysulfones, polyacrylates and polycycloolefins. The term “front resin sheet” means that the resin sheet is facing the mold cavity to duplicate the front (convex) surface of the whole lens. By the term “back”, we mean that the resin sheet is facing the lens base. The term “lens base” means the portion of the lens that is molded onto the laminate to form the main portion of the lens.
[0019] The objects of the present invention are further achieved by the careful design of the polyurethane composition used to host the photochromic dyes. The polyurethane layer material comprises a) a solid thermoplastic polyurethane, b) at least one aliphatic isocyanate-terminated polyurethane prepolymer, and c) at least one photochromic compound selected from a group consisting of spiropyrans, spiroxizines, fulgides, fulgimides, and naphthopyrans. The thermoplastic polyurethane has a theoretical NCO index from 90 to 105, and a molecular weight (number averaged) of from 9,000 to 100,000. The isocyanate prepolymer has a NCO content of from 1.0% to 10.0%, by weight. The weight ratio of the thermoplastic polyurethane vs. the isocyanate prepolymer is in the range from 1:9 to 9:1. The photochromic compound(s) counts for 0.1% to 5% of the total polyurethane, by weight.
[0020] To enhance the fatigue resistance of the photochromic compounds, stabilizers such as antioxidants, light stabilizers, and UV absorbers are added in the polyurethane layer.
[0021] The photochromic laminate is preferably made through a cast-lamination process. All components described above are dissolved in a suitable solvent, cast on a release liner. After the solvent is evaporated substantially, the thermoplastic polyurethane portion will provide the cast polyurethane film enough rigidity to go through the lamination process without any deformation. After lamination, the polyurethane prepolymer will provide further curability by reacting with active hydrogen atoms in the system to enhance the dimensional stability of the polyurethane layer under high temperature and high pressure.
[0022] Although the photochromic laminate according to this invention is especially suitable for making photochromic polycarbonate lenses through the insert injection molding process, other non-limiting uses include photochromic transparencies such as goggles and face shields.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides a photochromic polyurethane laminate having two transparent resin sheets bonded to a photochromic polyurethane layer formed by curing a mixture of a solid thermoplastic polyurethane, at least one isocyanate prepolymer, at least one photochromic compound, and a stabilizing system. The thermoplastic polyurethane has a theoretical NCO index of from 90 to 105, and a molecular weight (number averaged) of from 20,000 to 100,000. The isocyanate prepolymer has a NCO content of from 1.0% to 10.0%, by weight. The weight ratio of the thermoplastic polyurethane vs. the isocyanate prepolymer in the photochromic polyurethane composition is in the range from 1:9 to 9:1. The photochromic compound(s) counts for 0.1% to 5% of the total polyurethane, by weight.
[0024] To enhance the fatigue resistance of the photochromic compounds, stabilizers such as antioxidants, light stabilizers, and UV absorbers are added in the polyurethane layer.
[0025] The photochromic laminate is preferably made through a cast-lamination process. All components described above are dissolved in a suitable solvent, cast on a release liner. After the solvent is evaporated substantially, the thermoplastic polyurethane portion will provide the cast polyurethane film enough rigidity to go through the lamination process without any deformation. After lamination, the polyurethane prepolymer will provide further curability by reacting with active hydrogen atoms such as those of terminal hydroxyl groups, moisture, urethane groups, and urea groups in the system to enhance the dimensional stability of the polyurethane layer under high temperature and high pressure.
[0026] Transparent Resin Sheets
[0027] The material used to make the transparent resin sheet is not limited so long as it is a resin with high transparency. In case the photochromic polyurethane laminate of the present invention is incorporated into a thermoplastic article such as a spectacle lens, the transparent resin sheets of the laminate is preferably of a resin material that is thermally fusible to the article base material so that the photochromic laminate is tightly integrated with the article base when produced with the insert injection molding process. Thus, it is more preferred to have same kind of material for both the article base and the transparent resin sheets.
[0028] Suitable sheet resin materials include polycarbonate, polysulfone, cellulose acetate butyrate (CAB), polyacrylates, polyesters, polystyrene, copolymer of an acrylate and styrene, blends of compatible transparent polymers. Preferred resins are polycarbonate, CAB, polyacrylates, and copolymers of acrylate and styrene. A polycarbonate-based resin is particularly preferred because of high transparency, high tenacity, high thermal resistance, high refractive index, and most importantly, and especially its compatibility with the article base material when polycarbonate photochromic lenses are manufactured with the photochromic polyurethane laminate of the present invention and the insert injection molding process. A typical polycarbonate based resin is polybisphenol-A carbonate. In addition, examples of the polycarbonate based resin include homopolycarbonate such as 1,1′-dihydroxydiphenyl-phenylmethylmethane, 1,1′-dihydroxydiphenyl-diphenylmethane, 1,1-dihydroxy-3,3′-dimethyldiphe-nyl-2,2-propane, their mutual copolymer polycarbonate and copolymer polycarbonate with bisphenol-A.
[0029] While the thickness of a transparent resin sheet is not particularly restricted, it is typically 2 mm or less, and preferably 1 mm or less but not less than 0.025 mm.
[0030] Thermoplastic Polyurethane
[0031] As the thermoplastic polyurethane, it is preferably made from a diisocyanate, a polyol, and a chain extender. Thermoplastic polyurethanes of this kind are known and may be obtained, for example, in accordance with U.S. Pat. Nos. 3,963,679 and 4,035,213, the disclosures of which are incorporated herein by reference.
[0032] The thermoplastic polyurethane used in the present invention is particularly prepared from a composition comprising a) an aliphatic isocyanate having a functionality of 2, b) at least one high molecular weight polyol having a nominal functionality of 2 and a molecular weight of from 500 to 6000 g/mole, preferably from 700 to 3000 g/mol, and counting for from about 50% to about 98% by weight, preferably from 70% to 95%, of the total isocyanate reactive species in the composition, and c) at least one low molecular weight diol having a molecular weight of from 62 to 499, and counting for from about 2% to about 50% by weight, preferably from 5% to 30%, of the total isocyanate reactive species in the composition.
[0033] Polyols
[0034] The polyols of the present invention are those conventionally employed in the art for the preparation of polyurethane cast elastomers. Naturally, and often times advantageously, mixtures of such polyols are also possible. Examples of the suitable polyols include polyether polyols, polyester polyols, polyurethane polyols, polybutadiene polyol, and polycarbonate polyols, while polyether and polyester types are preferred.
[0035] Included among suitable polyether polyols are polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polytetramethylene glycol, block copolymers, for example, combinations of polyoxypropylene and polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethylene glycols, poly-1,4-tetramethylene and polyoxyethylene glycols, and copolymer glycols prepared from blends or sequential addition of two or more alkylene oxides. The polyalkylene polyether polyols may be prepared by any known process such as, for example, the process disclosed in Encyclopedia of Chemical Technology, Vol. 7, pp. 257-262, published by Interscience Publishers, Inc. (1951), the disclosure of which is incorporated herein by reference.
[0036] Polyethers which are preferred include the alkylene oxide addition products of polyhydric alcohols such as ethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, hydroquinone, resorcinol glycerol, glycerine, 1,1,1-trimethylol-propane, 1,1,1-trimethylolethane, pentaerythritol, 1,2,6-hexanetriol, .alpha.-methyl glucoside, sucrose, and sorbitol. Also included within the term “polyhydric alcohol” are compounds derived from phenol such as 2,2-bis(4-hydroxyphenyl)-propane, commonly known as Bisphenol A.
[0037] The suitable polyester polyols include the ones which are prepared by polymerizing ε-caprolactone using an initiator such as ethylene glycol, ethanolamine and the like. Further suitable examples are those prepared by esterification of polycarboxylic acids. Further suitable polyester polyols include reaction products of polyhydric, preferably dihydric alcohols to which trihydric alcohols may be added and polybasic, preferably dibasic carboxylic adds. Instead of these polycarboxylic adds, the corresponding carboxylic add anhydrides or polycarboxylic add esters of lower alcohols or mixtures thereof may be used for preparing the polyesters. The polycarboxylic adds may be aliphatic, cycloaliphatic, aromatic and/or heterocyclic and they may be substituted, e.g., by halogen atoms, and/or unsaturated. The following are mentioned as examples: succinic add; adipic add; suberic add; azelaic add; sebacic add; phthalic add; isophthalic add; trimellitic add; phthalic add anhydride; tetrahydrophthalic add anhydride; hexahydrophthalic add anhydride; tetrachlorophthalic add anhydride, endomethylene tetrahydrophthalic add anhydride; glutaric add anhydride; maleic add; maleic add anhydride; fumaric add; dimeric and trimeric fatty acids such as oleic acid, which may be mixed with monomeric fatty acids; dimethyl terephthalates and bis-glycol terephthalate. Suitable polyhydric alcohols include, e.g., ethylene glycol; propylene glycol-(1,2) and -(1,3); butylene glycol-(1,4) and -(1,3); hexanediol-(1,6); octanediol-(1,8); neopentyl glycol; (1,4-bis-hydroxymethylcyclohexane); 2-methyl-1,3-propanediol; 2,2,4-trimethyl-1,3-pentanediol; Methylene glycol; tetraethylene glycol; polyethylene glycol; dipropylene glycol; polypropylene glycol; dibutylene glycol and polybutylene glycol, glycerine and trimethlyolpropane. A preferred polyester polyol is polycaprolactone polyol having an average molecular weight from 500 to 6,000, and preferably from 700 to 3,000.
[0038] Diols
[0039] Suitable diols are those polyols listed above having a functionality of 2 and a molecular weight of from 62 to 499. Preferred dols are 1,4-butane-diol and 1,3-propane-diol.
[0040] Isocyanates
[0041] The diisocyanate component is preferably an aliphatic diisocyanate. The aliphatic diisocyanate is selected from the group consisting of 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate, 1-isocyanato-2-isocyanatomethyl cyclopentane, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cyclohexane (isophorone diisocyanate or IPDI), bis-(4-isocyanatocyclohexyl)-methane, 2,4′-dicyclohexylmethane diisocyanate, 1,3- and 1,4-bis-(isocyanatomethyl)-cyclohexane, bis-(4-isocyanato-3-methylcyclohexyl)-methane, .alpha.,.alpha.,.alpha.′,.alpha.′-tetramethyl-1,3- and/or -1,4-xylylene diisocyanate, 1-isocyanato-1-methyl-4(3)-isocyanatomethyl cyclohexane, 2,4- and/or 2,6-hexahydrotoluoylene diisocyanate, and mixtures thereof. Bis-(4-isocyanatocyclohexl)-methane is the preferred diisocyanate in occurrence with the method of the present invention.
[0042] The polymerization process to make the thermoplastic polyurethane can be carried out in one-pot fashion, that is, all starting materials are initially added into the reaction vessel. The polymerization process can also be carried out with a prepolymer approach. That is, a polyurethane prepolymer terminated with isocyanate groups is first obtained by reacting a stoichiometrically in excess diisocyanate with a polyol. Suitable equivalent ratio of diisocyanate to polyol in the present invention is from 1.2:1.0 to 8.0:1.0. A chain extender of diol is then mixed with the prepolymer to complete the reaction. The NCO index of the thermoplastic polyurethane, formed from the quotient, which is multiplied by 100, of the equivalent ratio of isocyanate groups to the sum of the hydroxyl groups of polyol and chain extender is within a range of 90 to 105, preferably between 92 and 101.
[0043] Catalysts such as organotin or other metallic soaps may be added in the mixture to make a thermoplastic polyurethane. Example catalysts include dibutyltin dilaurate, stannous octoate, and cobalt naphthenate.
[0044] Isocyanate Prepolymer
[0045] The isocyanate prepolymer used in the photochromic polyurethane composition of the present invention is prepared in the same way as the prepolymer used to prepare the thermoplastic polyurethane in a prepolymer method described above. Preferably, the polyol and the isocyanate used to make the isocyanate prepolymer is the same as the polyol to make the thermoplastic polyurethane. More preferably, the isocyanate is an aliphatic diisocyanate described in the previous sections, and the polyol is a polyester polyol having a molecular weight between 700 and 3,000. The molecular weight (number averaged) of the isocyanate prepolymer is preferably between 1,000 and 6,000, and more preferably between 1,500 and 4,000. As an isocyanate group terminated prepolymer, its NCO content is between 1.0% and 10.0%, preferably between 2.0% and 8.0%.
[0046] When mixing the isocyanate prepolymer and the thermoplastic polyurethane together, the mixing ratio by weight is in the range from 1:9 to 9:1, preferably from 1:3 to 3:1.
[0047] Photochromic Compounds
[0048] Suitable photochromic compounds in the context of the invention are organic compounds that, in solution state, are activated (darken) when exposed to a certain light energy (e.g., outdoor sunlight), and bleach to clear when the light energy is removed. They are selected from the group consisting essentially of benzopyrans, naphthopyrans, spirobenzopyrans, spironaphthopyrans, spirobenzoxzines, spironaphthoxazines, fulgides and fulgimides. Such photochromic compounds have been reported which, for example, in U.S. Pat. Nos. 5,658,502, 5,702,645, 5,840,926, 6,096,246, 6,113,812, and 6,296,785; and U.S. patent application Ser. No. 10/038,350, all commonly assigned to the same assignee as the present invention and all incorporated herein by reference.
[0049] Among the photochromic compounds identified, naphthopyran derivatives are preferred for optical articles such as eyewear lenses. They exhibit good quantum efficiency for coloring, a good sensitivity and saturated optical density, an acceptable bleach or fade rate, and most importantly good fatigue behavior. These compounds are available to cover the visible light spectrum from 400 nm to 700 nm. Thus, it is possible to obtain a desired blended color, such as neutral gray or brown, by mixing two or more photochromic compounds having complementary colors under an activated state.
[0050] More preferred are naphtho[2,1b]pyrans and naphtho[1,2b]pyrans represented by the following generic formula:
[0000]
[0051] Substituents on various positions of the aromatic structure are used to tune the compounds to have desired color and fading rate, and improved fatigue behavior. For example, a photochromic dye may contain a polymerizable group such as a (meth)acryloyloxy group or a (meth)allyl group, so that it can be chemically bonded to the host material through polymerization.
[0052] The quantity of photochromic compound(s) incorporated into the polyurethane layer of the present invention is determined by the desired light blockage in the activated state and the thickness of the polyurethane layer itself. The preferred outdoor visible light transmission of sunglasses is preferably between 5% and 50%, more preferably between 8% and 30%, most preferably between 10% and 20%. Preferably, the amount of total photochromic substance incorporated into or applied on the polyurethane layer may range from about 0.1 wt. % to about 5 wt % of the total polyurethane, and more preferably from about 0.5 wt. % to about 3.0 wt. %. If the thickness of the polyurethane layer is 100 μm, between about 0.5 wt. % to about 1 wt. % of photochromic compound(s) is needed to achieve an outdoor light transmission of between 10% and 20%. The amount of photochromic compound(s) needed is inversely proportional to the thickness of the polyurethane layer. In other words, to achieve the same outdoor light transmission the thicker the polyurethane layer, the lower the concentration of photochromic compound(s) needed. The concentration of the photochromic compound(s) also depends on the color intensity of the photochromic compound(s) at the activated state.
[0053] Stabilizers
[0054] Additives such as antioxidants and light stabilizers are incorporated into the polyurethane layer in order to improve the fatigue resistance of the photochromic compounds. Hindered amines are usually used as light stabilizers, and hindered phenols are usually used as antioxidants. Preferred hindered amine light stabilizers include, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-sebacate, or a condensation product of 1,2,2,6,6-pentamethyl-4-piperidinol, tridodecyl alcohol and 1,2,3,4-butanetetra carboxylic acid as tertiary hindered amine compounds. Preferred phenol antioxidants include, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, tetrakis-[methylene-3-(3′,5′-di-t-butyl-4-hydroxy-phenyl)propionate]methane, and 1,3,5-tris(3,5-di-t-butyl-4-hyroxybenzyl)-1,-3,5-triazine-2,4,6-(1H,3H,5H)-trione. Phenol antioxidants that contain 3 or more hindered phenols are preferable.
[0055] Process to Make the Laminate
[0056] A photochromic laminate having a polyurethane layer in between two transparent resin sheets in accordance with the present invention may be produced through a variety of processes. Depending on the nature of the starting material to the polyurethane, processes such as casting-lamination (also referred to in the art as coating-lamination), and extrusion-lamination may be used.
[0057] To the photochromic polyurethane composition of the present invention, a novel casting-lamination process has been developed by the inventors. The process essentially comprises: a) preparing a solvent casting solution by dissolving a solid thermoplastic polyurethane, at least one isocyanate polyurethane prepolymer, at least one photochromic compound, and optional stabilizers in a proper solvent; b) cast the solution on a release liner film; c) remove the solvent from the cast film to a substantially dry state to form a photochromic polyurethane film; d) transfer-laminate the photochromic polyurethane film between two transparent resin sheets; e) cure the photochromic polyurethane film, thereby forming a photochromic polyurethane laminate.
[0058] To cast a photochromic polyurethane film, a thermoplastic polyurethane, an isocyanate prepolymer, selected photochromic compounds and other necessary additives are first dissolved in a suitable solvent or in a mix of solvents to form a cast solution. The solid concentration in such a solution is usually 15% to 50%, by weight, and the solution has a viscosity suitable for coating. For example, suitable viscosity of the cast solution for using a slot die method is within the range from 500 cPs to 5000 cPs. Examples of suitable solvents that may be used to dissolve polyurethanes include cyclohexane, toluene, xylene and ethyl benzene, esters such as ethyl acetate, methyl acetate, isopropyl acetate, n-propyl acetate, isobutyl acetate, n-butyl acetate, isoamyl acetate, methyl propionate and isobutyl propionate, ketones such as acetone, methylethyl ketone, diethyl ketone, methylisobutyl ketone, acetyl acetone and cyclohexyl ketone, ether esters such as cellosolve acetate, diethylglycol diacetate, ethyleneglycol mono n-butylether acetate, propylene glycol and monomethylether acetate, tertiary alcohols such as diacetone alcohol and t-amyl alcohol and tetrahydrofuran. Ethyl acetate, methyl ethyl ketone, cyclohexane, tetrahydrofuran, toluene and combinations thereof are preferable.
[0059] The solution is then cast on a release liner by using a method known to those skilled in the art, such as slot-die, knife-over-roll, reverse-roll, gravure, etc. Slot die and knife-over-film are referred. Slot die method is especially preferred due to its capability to handle wide range of solution viscosity and to cast uniform films. A release liner may consist of a base film and a release coating or simply a film itself. Films with surface energy low enough to provide easy release of the cast film can be used by itself. Examples include low energy polyolefins and fluoropolymers. Most commercially available release liners are based on polyester film coated with a release coating. The release coating has a proper surface energy so that a cast solution or coating forms a uniform film (e.g., without beading) on it. At the same time the release coating does not provide good adhesion to the dried film so that the film can be easily peeled off. Release coatings include silicone (siloxane) based and non-silicone base such as fluoropolymers. A liner based on polyester (PET) with cured siloxane release coating is preferred due to the dimensional stability, flatness, handling, solvent resistance, low cost. Suitable liners should have a thickness of from 25 micrometers to 130 micrometers.
[0060] The wet photochromic polyurethane film cast on the release liner is sequentially dried in a forced air oven system. The solvent will be substantially evaporated so that the solvent retention in the photochromic polyurethane film is low enough to not cause any defects (e.g., bubbling) in the future laminate. The solvent retention preferably is less than 2 wt. %, more preferably less than 1 wt. %, and most preferably less than 0.5 wt. %. Conventional methods such as hot air dryers may be used to evaporate the solvent before lamination. The drying conditions, such as temperature and air flow rate in the oven, for a desired solvent retention value depends on the nature of the solvent, the thickness of the cast film, the type of the release liner, and the web speed. The drying conditions should not be so aggressive to cause any surface defects in the cast film. Example defects are blisters (bubbles) and orange peel. Preferably, the drying oven system has multi-zones whose drying conditions are controlled separately.
[0061] The thickness of the dried photochromic polyurethane layer is from about 5 micrometers to about 150 micrometers. For using the photochromic laminate in an insert injection molding process to make plastic photochromic lenses, the thickness of the photochromic polyurethane is preferably between 5 micrometers and 80 micrometers. The thickness variation of the photochromic polyurethane layer should be controlled in order to produce a uniform light blockage at the activated state. A thickness variation of less than 15% over the width of the laminate is required and preferably less than 10% and more preferably less than 5%.
[0062] The transfer-lamination of the dried photochromic polyurethane film to two transparent resin sheets to form a laminate of the polyurethane film between the two resin sheets, may be done by either a sequential lamination process or an in-line lamination process. In a sequential lamination process, the dried polyurethane film on the release liner is first laminated to the first transparent resin sheet through a first lamination station. The semi-laminate consisting of the release liner, the polyurethane film, and the resin sheet, is then wound up on a core. The wind is then brought to a second lamination station where the release liner is peeled off and the second transparent sheet is laminated to the polyurethane film to form the final photochromic polyurethane laminate. The first and the second lamination stations may be the same one. The lamination may be conducted between two chrome coated steel rolls or between one steel roll and one rubber roll, although the later is preferred.
[0063] According to the findings of the inventors, an in-line lamination process is more preferred. In such a process, the second transparent resin sheet is immediately laminated to the semi-laminate without first winding the semi-laminate. The in-line lamination may be done with two two-roll lamination stations, or more conveniently be conducted on one three-roll setup in which the first roll and the second roll form a first nip, and the second roll and the third roll form a second nip. The dried polyurethane film on the release liner is first laminated to the first transparent resin sheet through the first nip. Without forming and winding a semi-laminate, the release liner is peeled off, and the second transparent resin sheet is immediately laminated to the exposed side of the polyurethane film on the first transparent resin sheet, through the second nip. This in-line lamination process will significantly increase the productivity. It also eliminates an extra winding step and reduces the possibilities of defects in the polyurethane film associated with the winding step. Example defects are de-lamination between the polyurethane film and the transparent resin sheet, impressions in the polyurethane film caused by possible external particles under winding pressure.
[0064] The photochromic polyurethane laminate thus formed according to the present invention needs to be cured before application. The curing is preferably carried in two stages: a) ambient curing for 1 day to 1 week, b) post curing at elevated temperature of from 50° C. to 130° C. for 8 hours to 1 week.
[0065] If the solvent selected to dissolve the photochromic polyurethane composition does not whiten the transparent resin sheet, a direct cast on the resin sheet may be employed. In this case, a simple two-roll lamination setup is acceptable for making a photochromic polyurethane laminate.
[0066] In an alternative process, the photochromic layer from a thermoplastic polyurethane and isocyanate-terminated polyurethane prepolymer may be co-extruded utilizing a single- or twin-screw extruder. The extruded photochromic polyurethane film will then be immediately hot-laminated between two transparent resin sheets to form the photochromic polyurethane laminate. The photochromic compounds and other additives may be incorporated into the polyurethane during the resin synthesis stage or melt-mixed prior to extrusion.
[0067] Although the photochromic laminate according to the present invention is especially suitable for making photochromic polycarbonate lenses through the insert injection molding process described in commonly assigned U.S. Pat. No. 6,328,446, it can also be used as-is for other photochromic transparencies such as goggles and face shields. The photochromic laminate may also be incorporated into other types of eyewear lenses such as cast resin lenses with a process described in U.S. Pat. No. 5,286,419.
[0068] The photochromic polyurethane laminate in accordance with the present invention will now be illustrated with reference to the following examples, which are not to be construed as a limitation upon the scope of the invention in any way.
[0069] In the examples, all values are expressions of weight %. CR49 and CR59 are tradenames of photochromic dyes available from Corning Corp. Grey-762 is proprietary grey photochromic dye. Irganox-1010 as an antioxidant, Tinuvin-144 and Tinuvin-765 as light stabilizers are available from CIBA (Tarrytown, N.Y., US).
[0070] To visually evaluate the activation and the photochromic polyurethane layer uniformity, a photochromic laminate or lens was exposed to UV irradiation (12 mw/m2) for 5 minutes.
Example 1
Preparation of Isocyanate Polyurethane Prepolymer A
[0071] In a 3-necked flask equipped with an overhead stirrer, thermocouple, and a vacuum adapter, 393.5 g (3 equivalents) of 4,4′-dicyclohexylmethanediisocyanate (H12MDI, available from Bayer as Desmodur W) was charged into the reactor and stirred at ambient temperature, 1000 g (2 equivalents) of a polycaprolactone diol having an OH number of 112 mg KOH/g and a number average molecular weight of about 1000 g/mole (available from Dow Chemical as Tone™ 2221) was preheated in an oven to 80° C. and added to the reactor. The mixture was allowed to stir for about 15 minutes, before adding 6 g of dibutyltin dilaurate catalyst (available from Air Products as T-12). The reaction flask was evacuated (<0.1 mm HG) and held at 90° C. for 6 hours. An aliquot of the prepolymer was withdrawn and titrated for isocyanate content using standard n-butyl amine titration. The isocyanate content was found to be 2.92% (theory; 3.0%).
Example 2
Preparation of isocyanate Polyurethane Prepolymer B
[0072] In a 3-necked flask equipped with an overhead stirrer, thermocouple, and a vacuum adapter, 613.0 g (4.67 equivalents) of 4,4′-dicyclohexylmethanediisocyanate (H12MDI, available from Bayer as Desmodur W) was charged into the reactor and stirred at ambient temperature. 1000 g (2 equivalents) of a polycaprolactone diol having an OH number of 112 mg KOH/g and a number average molecular weight of about 1000 g/mole (available from Dow Chemical as Tone™ 2221) was preheated in an oven to 80° C. and added to the reactor. The mixture was allowed to stir for about 15 minutes, before adding 8 g of dibutyltin dilaurate catalyst (available from Air Products as T-12). The reaction flask was evacuated (<0.1 mm HG) and held at 90° C. for 6 hours. An aliquot of the prepolymer was withdrawn and titrated for isocyanate content using standard n-butyl amine titration. The isocyanate content was found to be 6.75% (theory, 7.0%).
Preparation of Thermoplastic Polyurethane
[0073] A thermoplastic polyurethane having a theoretical NCO index of 95 was prepared as following. The isocyanate prepolymer B (927.2 g) prepared in Example 2 was heated in vacuo (<0.1 mm HG) with stirring to 80° C. and 1,4-butane-diol (72.8 g) as the chain extender and 3 g of dibutyltin dilaurate catalyst were combined with the prepolymer while keeping stirring. The mixture was stirred for 30 seconds and subsequently poured into a Teflon lined tray. The tray containing the casting was cured in an oven at 85° C. for 24 hours.
Example 4
[0074] A solution was first made by dissolving 4 g of the thermoplastic polyurethane prepared in Example 3 in 16 g of anhydrous tetrahydrofuran. To the solution was further added 4 g of the isocyanate prepolymer prepared in Example 1, 0.14 g of CR49 dye, 0.02 g CR59 dye, 0.17 g each of Irganox-1010, Tinuvin-144, and Tinuvin-765. The mixture was stirred at room temperature for 3 hours before cast on an easy release liner (available from CPFilms as T-50) with draw bar targeting a 38 micrometer dry film thickness. The solvent in the cast film was evaporated at 60° C. for 5 minutes with airflow above the film. The dried film was transfer-laminated between two 0.3 mm thick polycarbonate sheets (available from Teijin as PC-1151) with a bench top roller laminator. After 4 days under ambient, the laminate was cured at 70° C. for 3 days.
[0075] The laminate was cut into a 76 mm disc and used to make a segmented multi-focal polycarbonate photochromic lens. After the insert injection molding process with common molding parameters, the finished lens had an acceptable thin, crisp segment line. No polyurethane bleeding from the laminate was observed. The lens showed quick and uniform photochromic activation. No any lamination defects were observed.
Example 5
[0076] A solution having 28.2% solid, was first prepared by dissolving 1950 g of the thermoplastic polyurethane prepared as in Example 3 in 7550 g of anhydrous tetrahydrofuran. To the solution was further added 780 g of the isocyanate prepolymer prepared as in Example 1, 59 g each of “762” dye, Irganox-1010, Tinuvin-144, and Tinuvin-765. The mixture was stirred at room temperature for 3 hours then set overnight before cast on an easy release liner (available from Saint-Gobain as 8310) at a web speed of 5.5 feet per minute in a pilot coater equipped with a slot die, a two-zone drying oven, and a three-roll lamination station. The solvent in the cast film was evaporated at 70° C. for 1 minute and 120° C. for another minute with forced airflow above the film. The dried film was 38 micrometer thick and had a solvent retention of 0.1%. It was transfer-laminated between two 0.3 mm thick polycarbonate sheets (available from Teijin as PC-1151) with an in-line process (without winding the semi-laminate of the release liner, polyurethane film, and the first polycarbonate sheet). After 4 days in ambient (22° C. and 35%˜50% RH), the laminate was cured at 70° C. for 3 days.
[0077] The laminate was cut into 76 mm discs and used to make a segmented multi-focal polycarbonate photochromic lenses. After the insert injection molding process with common molding parameters, the finished lens had an acceptable thin, crisp segment line. No polyurethane bleeding from the laminate was observed. The lens showed quick and uniform photochromic activation. No any lamination defects were observed.
Example 6
[0078] A solution having 35.3% solid, was first prepared by dissolving 1950 g of the thermoplastic polyurethane prepared as in Example 3 in 7742 g of anhydrous tetrahydrofuran. To the solution was further added 1950 g of the isocyanate prepolymer prepared as in Example 1, 68 g of CR49 dye, 10 g CR59 dye, 85 g each of Irganox-1010, Tinuvin-144, and Tinuvin-765. The mixture was stirred at room temperature for 3 hours then set overnight, then cast directly on a first 0.3 mm thick polycarbonate sheet (available from Teijin as PC1151) at a web speed of 5.5 feet per minute in a pilot coater equipped with a slot die, a two-zone drying oven, and a three-roll lamination station. The solvent in the cast film was evaporated at 94° C. for 1 minute and 127° C. for another minute with forced airflow above the film. The dried film was 25 micrometer thick and had a solvent retention of 0.1%. A second 0.3 mm thick polycarbonate sheet was laminated on the exposed side of the dried polyurethane film on the first polycarbonate sheet. After 4 days in ambient (22° C. and 35%˜50% RH), the laminate was cured at 70° C. for 3 days. The laminate obtained was clear. No solvent whitening on the polycarbonate sheets was seen.
Comparison Example 1
[0079] To 10 g of Hysol® (Loctite) U-10FL urethane adhesive resin are dissolved 1.5% of “762” dye, 2.0% of Tinuvin 144, and 2.0% of Tinuvin 765. Then, 9.1 g of Hysol® U-10FL urethane adhesive hardener is mixed in to form a liquid adhesive.
[0080] The adhesive was coated with a draw bar directly on a polycarbonate sheet (0.3 mm thick, available from Teijin as 1151) to form a 38 micrometer cast film. Another polycarbonate sheet was laminated onto the adhesive through a bench top roller laminator. Some adhesive was squeezed out. The laminate was allowed to cure at room temperature overnight, then is post cured at 65° C. for 10 hours.
[0081] When the photochromic laminate was activated, thin spots (lightly activated due to thinner spots in the polyurethane layer) and non-uniformity of activation due to thickness gradient across the laminate were observed.
Comparison Example 2
[0082] Example 4 was followed, except the isocyanate prepolymer was neglected. The photochromic polyurethane layer was 38 micrometers thick. The laminate showed uniform photochromic activation. No lamination defects were observed. However, when molded into a polycarbonate lens as in Example 4, severe polyurethane bleeding was observed at the edge of the laminate.
[0083] The foregoing detailed description of the preferred embodiments of the invention has been provided for the purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Many modifications and variations will be apparent to practitioners skilled in the art to which this invention pertains. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. | A photochromic polyurethane laminate that is constructed to solve certain manufacturing difficulties involved in the production of plastic photochromic lenses is disclosed. The photochromic laminate includes at least two layers of a resinous material and a photochromic polyurethane layer that is interspersed between the two resinous layers and which contains photochromic compounds. The polyurethane layer is formed by curing a mixture of a solid thermoplastic polyurethane, at least one isocyanate prepolymer, at least one photochromic compound, and a stabilizing system. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a U.S. National Stage application of International Application No. PCT/US2009/037755, filed Mar. 20, 2009, the disclosure of which is hereby incorporated by reference herein in its entirety.
TECHNICAL FIELD
The present invention relates to a data protocol to implement a wireless voice and data communication system that for use in underground and hazardous areas for dispatch, remote supervision, and tracking of personnel, as well as, monitoring, asset control, and management of wireless sensors and equipment. More specifically the protocol enables the creation of a wireless ad hoc mesh network and facilitates the transport of communication packets for voice, data, text and network operations supporting normal and emergency operation.
BACKGROUND OF THE INVENTION
Recent events have indicated the need for reliable communication systems during emergencies in underground and hazardous work areas such as coal mines. During a mine disaster the current voice and data communication systems fail or shutdown so the conditions of personnel, environment and equipment is unknown which complicate recovery efforts. Past mining accidents have demonstrated that current communication systems are not sufficient to provide the support required to effectively handle evacuation and rescue operations. The 2006 MINER Act amends the Federal Mine safety and Health Act of 1977 stating underground coal mine operators must provide for post accident communication between underground and surface personnel via a wireless two-way medium within three years. Robust and reliable mine communications are critical for both mining operations and in the event of a mine emergency. The National Institute for Occupational Safety and Health (NIOSH) released a solicitation in late 2006 for an underground communication system that is highly reliable and provides in-mine and mine-to-surface voice and data communications to evaluate wireless mesh network technology as part of an underground communications system.
Prior art mesh communications systems for use in hazardous environments have used the standard Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless protocol to transfer status and multimedia information as well as centrally generated and controlled routing tables to control packet latency in a multi-cast application with a changing network topography. The IEEE802.11 wireless protocol supports an infrastructure mode in which mobile nodes are connected to a coordinating master referred to as the Access Point (AP) and an ad hoc mode in which mobile nodes form peer-to-peer connections with no preconfigured network topology. The original 802.11 protocol had very limited Quality of Service (QoS) mechanisms. A Point Coordination Function (PCF) was specified in which each AP sends a poll to each client one at a time to provide a contention-free transmission opportunity. This media access control (MAC) method has not been implemented in many APs and is bandwidth inefficient since it always requires a poll packet be sent to the client for each high priority packet to be sent to the AP. The 802.11e amendment was incorporated into the 802.11 standard in 2007. It specifies two additional mandatory QoS MAC methods. The first method is the Enhanced Distributed Channel Access (EDCA) method which specifies traffic priority levels and assigned transmission opportunities for each priority level. This method does protect against collisions (and subsequent loss) of high-priority packets due to low-priority packets, however it does not protect against collisions of packets with the same priority from multiple clients. The second QoS method introduced by 802.11e is an infrastructure-only method referred to as Hybrid Coordinator Function Controlled Channel Access (HCCA). This QoS method is similar to the PCF method with the exceptions of the timing of the contention-free transmission opportunities is not limited to certain inter-beacon time slots and the AP is able to poll a client for a particular Traffic Class (TC) to enable session-aware QoS. This HCCA method suffers from the same bandwidth inefficiency as PCF. In addition to the lack of an efficient method to guarantee transmission opportunities for high priority packets between a client and an AP (infrastructure mode) or between two clients (ad hoc mode), the 802.11 solutions do not provide the additional necessary capability to forward said packet to the next destination in the network in an efficient and contention-free manner. Therefore, what is needed is a method and apparatus for establishing dedicated transmission opportunities for each fixed node in a given cluster to forward packets to the next node in the cluster as well as contention-based transmission opportunities for fixed nodes and mobile nodes to join the cluster.
Furthermore, the efficient routing of packets across a mesh network is a vital component in determining the packet latency through the network. Prior art mesh network communication systems for hazardous environments have utilized routing tables generated from a centralized location and periodically propagated across the network using high priority MAC message mechanisms, resulting in a delay in routes being modified as conditions change. There is also a need in the art for an intelligent de-centralized flood routing technique to ensure mobile units can seamlessly roam throughout the network.
SUMMARY OF INVENTION
This invention relates to a computer-implemented method for providing a protocol enabling reliable communications between elements of an ad hoc mesh network which include at least fixed mesh nodes, mobile mesh radio nodes and gateway nodes. One of the fixed mesh nodes is designated a time master node, and an intelligent de-centralized flood routing technique is used to ensure that units containing mobile mesh radio nodes can seamlessly roam throughout the network. Each fixed mesh node transmits over a pair of bonded, time-synchronized channels, one of which is a voice channel while the other is a data channel.
The protocol includes at least one super-frame time interval. If there is more than one super-frame time interval, they are all of equal duration and synchronized with the time master node. There are at least two time slots within the primary level of each super-frame, one of which is assigned to be a first level contention access period time slot and the second of which is assigned to be a period during which fixed mesh nodes may transmit network packets to neighboring fixed mesh nodes and to any mobile mesh radio nodes with which they are associated. The protocol has multiple levels of time slots, each of which is assigned to a specified type of activity to account for the various functions to be provided by the protocol.
BRIEF DESCRIPTION OF DRAWINGS
The foregoing and other objects, aspects and advantages of the invention will be better understood from the following detailed description of the invention with reference to the drawings, in which
FIG. 1 illustrates the concept of a wireless voice and data ad hoc mesh network deployment in a logical design block diagram view according to an embodiment of the present invention.
FIG. 2 illustrates an example of a cluster of Fixed Mesh Nodes, depicting the parent-child relationships as well as the transceiver operation during a typical protocol super-frame.
FIG. 3 illustrates the partitioning of a protocol super-frame into first level time slots as defined by this invention.
FIG. 4 illustrates the partitioning of a first level FMN-to-FMN time slot into second level time slots as defined by this invention.
FIG. 5 illustrates the partitioning of a first level Data Channel Contention Access Period (CAP) time slot into second and third level time slots as defined by this invention.
FIG. 6 illustrates the partitioning of a first level Voice Channel Contention Access Period (CAP) time slot into second and third level time slots as defined by this invention.
FIG. 7 illustrates the partitioning of a generic first level frame into second and third level frames as defined by this invention.
FIG. 8 illustrates the partitioning of a third level Frame Control Field frame into fourth level frames as defined by this invention.
FIG. 9 illustrates the partitioning of a third level Extended Header frame into fourth level frames as defined by this invention.
FIG. 10 illustrates the partitioning of a generic fourth level Extended Header frame into fifth level frames as defined by this invention.
FIG. 11 illustrates the partitioning of a fourth level Slot Info Extended Header frame into fifth level and sixth level frames as defined by this invention.
FIG. 12 illustrates the partitioning of a sixth level Cycle Slot #/Foster Rotation frame of a fourth level Slot Info Extended Header frame into seventh level frames as defined by this invention.
FIG. 13 illustrates the partitioning of a fourth level Piggyback Acknowledge (ACK) Extended Header frame into fifth level and sixth level frames as defined by this invention.
FIG. 14 illustrates the partitioning of a fourth level Piggyback Grant Extended Header frame into fifth level and sixth level frames as defined by this invention.
FIG. 15 illustrates the partitioning of a fourth level Future Grant Extended Header frame into fifth and sixth level frames as defined by this invention.
FIG. 16 illustrates the partitioning of a first level Single Data Frame Packet into second level, third level and fourth level frames as defined by this invention.
FIG. 17 illustrates the partitioning of a first level Concatenated Data Frame Packet into second level, third level and fourth level frames as defined by this invention.
FIG. 18 illustrates the partitioning of a first level SYNC MAC frame into second level, third level and fourth level frames as defined by this invention.
DETAILED DESCRIPTION OF THE INVENTION
This invention helps to provide reliable voice and data communications with personnel and sensors within a hazardous area and also with a remote operation center during normal operations as well as during an event that requires shut down of normal operations. The invention allows rescue teams to determine personnel status, where personnel are located, and environment conditions such as water, toxic gases, and oxygen availability in the hazardous area. The wireless voice/data network protocol of the present invention comprises a number of intercommunicating blocks which automatically form a Wireless Mesh Network (WMN) 100 that can reform when links are removed or blocked.
The system and method of the present invention provide a voice/data network protocol to supply Operations Center staff with event detection information, voice and text communications, and personnel location information, as illustrated in FIG. 1 . In a preferred embodiment, four types of nodes are provided in the network:
Fixed Mesh Node FMN 102 is a stationary dual-transceiver mesh radio unit operates on the WMN 100 . Multiple units operate together to form the semi-static infrastructure for the WMN 100 . Each FMN 102 has the capability to coordinate individual clusters within the wireless mesh network WMN 100 and route data through the network between mobile nodes and to a Gateway Node (GWN) 104 . An FMN 102 can also communicate through a wired backbone headend 106 with a wired backbone 107 , such as a leaky feeder system, as well as form the core links for WMN 100 .
GWN 104 supports the transfer of information between WMN 100 and the infrastructure for a wide area network (WAN). GWN 104 is a highly modular design that is normally implemented as a fixed device but could be a mobile device. GWN 104 includes all of the functions of a full function FMN 102 .
Mobile Mesh Radio (MMR) 101 is a portable device carried by personnel that allows them to have voice and data communication with a Network Operations Center 105 and/or other personnel equipped with an MMR 101 . MMR 101 can also be a relay link between another MMR 101 and an FMN 102 , or between a sensor mesh node (SMN) 103 and an FMN 102 .
SMN 103 connects data from various types of sensors such as light, noxious gas, acoustic, temperature, oxygen, and imaging sensors into WMN 100 by communicating through one or more FMNs 102 or one or more MMRs 101 to forward information from a sensor to network operations center (NOC) 105 .
Other units may also be added to WMN 100 . For example, a Data Mesh Node may be used to communicate with equipment operating in a mine or hazardous area. Thus, use of this invention is not limited to the types of nodes specifically mentioned.
1. Definitions
The following terms are used throughout this description with the following meanings:
Node—This term is used to denote a Fixed Mesh Node (FMN) 102 , Gateway Node (GWN) 104 , Mobile Mesh Radio (MMR) 101 or Sensor Mesh Node (SMN) 103 .
Time Master—This term refers to the node which is providing the protocol super-frame timing to all the other nodes in a cluster. This node may have direct children nodes and if it does it may have inherited children through these children. Its direct children of the Time Master will directly synchronize to the time master's slot timing while the inherited children will synchronize to their respective parents slot timing thus inheriting the time master's timing with some offset due to propagation delay. For example, in FIG. 2 , Node 1 is the Time Master; Node 2 is the only direct child of Node 1 while Nodes 3 and 4 are the inherited children of Node 1 through Node 2 .
Cluster—A cluster is a group of nodes which all have the same time master. Nodes in a cluster do not necessarily (and often will not) have direct RF connectivity to all the other nodes in the cluster. Information packets between clusters pass through a pair of gateways if a gateway exists in each cluster. FIG. 2 illustrates a cluster of FMN's containing nodes 1 , 2 , 3 and 4 .
Parent Node—A parent node is a node which is providing a time reference to a child node. In FIG. 2 , a parent-child relationship is illustrated by the lines towards which indicator 205 points in which the arrowhead for each of the lines points towards that node's parent. Thus, node 1 is the parent of node 2 while node 2 is the parent of node 3 and node 4 . The numbering system for the nodes is described in further detail below.
Child Node—A child node is a node which is basing its time reference on a parent node. The only node in a cluster which is not a child to some parent is the time master.
Peer Node—A peer node is a node which has the same time reference as a given node but is not a child or parent of that node. In FIG. 2 , a peer relationship is illustrated by a line without arrowheads, such as line 210 .
Observing Node—A node which is examining the frequency spectrum for adjacent nodes, parent node, children nodes, peer nodes, and known nodes.
Known Node—A node is said to be a known node to an observing node if its presence is known by the observing node but it is not in the same cluster as the observing node.
Neighbor—A node is considered to be a neighbor of another node if it is the parent, a child or a peer to that node. Known nodes are not considered to be neighbors.
Orphan Node—An orphan node is a node which is currently operating in a dedicated search mode. In this mode it will continually search for any node with a higher time master ranking than it has itself.
Orphan Cluster—An orphan cluster is a cluster which does not contain a gateway.
Wireless Mesh Network (WMN) 100 —Refers to the mesh network in its entirety, including FMNs 102 , GWNs 104 , MMRs 101 and SMNs 103
2. Functional Overview
The mesh protocol provides a means to form and maintain the fixed network (FMNs 102 and GWNs 104 ) and provides access into the network for mobile nodes (MMRs 101 and SMNs 103 ). The fundamental purpose of this network is to transmit application layer packets between various points in the system with the highest reliability and lowest latency which can be achieved given a certain system cost.
Since a GWN 104 operates as a mesh network member in a manner which is indistinguishable from an FMN 102 on the mesh radio side, the term FMN 102 will be used in the remainder of this description when referencing functionality common to both FMN 102 and GWN 104 .
3. Frequency and Slot Assignment
An important aspect of this invention is the ability to form a mesh network which can provide dedicated bandwidth for each FMN 102 within a cluster. This dedicated bandwidth is essential in the efficient routing of voice communications which is very sensitive to any system latency. When an FMN 102 attempts to join an existing cluster of FMN's 102 it sends an Association Request to the FMN 102 which it has determined to be its best parent. The potential parent responds with an Association Response indicating whether it accepts or rejects the joining FMN 102 as a child. In the case of the former, the parent FMN 102 provides a channel and slot assignment on which the joining FMN 102 is to operate. In this way the bandwidth within a cluster can be managed such that, within a given RF collision domain, each cluster member has a unique RF channel/time slot combination for it to transmit its FMN-to-FMN messages in time slots 310 within super-frame 305 , shown in FIG. 3 .
4. Mesh Operation
FIG. 2 illustrates the operation of a small mesh consisting of 4 nodes. For purposes of this description each node is referenced by its ID, i.e. Node 1 is the node with an ID of 1. Each node has a frequency pair associated with it, one for the primary channel and one for the secondary channel. This frequency pair is “bonded” since there is a fixed relationship between them and if one is known, the other can be easily derived. For example, Node 3 in FIG. 2 operates with a primary frequency of f 7 and a secondary frequency of f 7 ′. Each node learns the frequency pair associated with each of its neighbors during cluster formation.
In addition each node has a first level FMN-to-FMN time slot 310 associated with it. For example Node 4 in FIG. 2 has time slot 0 associated with it. The time slot for each member of a cluster is assigned during cluster formation.
As illustrated in FIG. 2 , during a typical super-frame, each node will tune its primary and secondary transceiver frequencies to its assigned frequencies during its assigned first level FMN-to-FMN time slot 310 and transmit any packets it has queued for transmission on that channel as described previously. In addition, during a typical super-frame, for each first level FMN-to-FMN time slot 310 which is assigned to a neighbor, a node will tune its transceivers to the frequencies associated with that neighbor and attempt to receive packets from that neighbor. Also during a typical super-frame, each node will tune its transceivers to its assigned frequencies during the first level contention access period (CAP) time slot 315 , shown in FIG. 3 and explained further below, attempting to receive packets from transmitting mobile nodes or other FMNs 102 which are attempting to join the cluster. Finally, during any first level FMN-to-FMN time slot 310 which is not currently assigned to a neighbor, a node will use both transceivers to scan for other clusters which might provide an improved time metric.
Exceptions to this typical super-frame operation are made in order to allow nodes to discover other nodes associated with other clusters when these other nodes are operating in time slots which overlap the time slots assigned to discovering node or the discovering node's neighbors. These exceptions are known as puncturing events. A node will periodically puncture its own first level FMN-to-FMN time slot 310 , as well as its neighbors' assigned time slot(s) and the first level CAP time slot 315 . During a puncturing event, the node performing the puncturing will replace the typical operation described in the preceding paragraph with a scan operation. The puncturing schedule for the two transceivers for a given node is independent.
5. Routing
In order to support multicast communications, seamless mobility for mobile nodes such as MMRs 101 and SMNs 103 and redundant communications links, the routing of voice packets through the mesh network must be dynamic. This invention accomplishes this using an intelligent flood routing technique.
Mobile nodes transmit and receive with the FMN 102 which provides the best communications path at that given time; this FMN 102 is considered to be the mobile node's parent at that time. As a mobile node travels through the network its position relative to a given parent changes and therefore the RF characteristics change. When the quality of the link between the mobile node and its parent FMN 102 has degraded such that it is below a programmable threshold of acceptable operation, the mobile node seeks another parent which can provide a higher quality communication link. This results in the entry point of the voice and data packets into the network changing with time.
In addition to mobility, the occasional removal of one or more FMNs 102 from the network is an operational reality. This can occur due to maintenance action, failure of a unit or loss of line of sight between units due to obstructions or cave-in. Each of these scenarios can cause a modification to the current route which packets are taking through the network. Since the intelligent flood routing algorithm used by the current invention does not attempt to establish any static or semi-static routes for communication packets from a given source to a given destination, it is able to immediately react to each of these scenarios with minimal or no loss of data.
Flood routing is understood to those skilled in the art to be a technique by which a router forwards packets received on all interfaces except the one on which said packet was received. This is known to artisans as a technique which can be used to add multicast support to a mesh network. However, this technique can result in large amounts of redundant traffic since there are many possibilities for circular routing loops. The present invention eliminates circular loops by storing a history of data packet sequence numbers and voice packet timestamps. As each data packet is forwarded, its sequence number is recorded in memory along with a timestamp indicating the current system time. If another data packet is received with this same sequence number before a programmable timeout period, this packet is discarded. However if the sequence number of the data packet does not match any stored sequence number of recently forwarded packets, the packet is forwarded and the timestamp associated with that sequence number is replaced with the current time.
A similar procedure is used for filtering duplicate voice packets, however timestamps are used instead of sequence numbers to eliminate the possibility of forwarding a voice packet associated with a given voice stream which is significantly older than a previously forwarded voice packets associated with the same voice stream. Each voice packet contains two timestamps, one which indicates the time at which the first voice packet of the associated voice stream was transmitted into the network and one which indicates the time at which this specific packet of the stream was transmitted into the network. As each voice packet is received by a FMN 102 it will only be forwarded if no other voice packet was recently forwarded with the same voice stream origination time and a packet origination time which is greater than or equal to the packet origination time in packet under consideration. In a preferred embodiment of this invention the definition of “recently” is controlled by a configurable timeout parameter.
6. Super-Frame Format
All transmissions on the mesh network are strictly time synchronized to increase the likelihood of successful transmission of any given packet. Each FMN 102 utilizes a pair of bonded channels on which it will transmit. FIG. 3 illustrates the super-frame timing used on both of these channels. The timing of the super-frames 305 on each channel is synchronized to prevent an FMN 102 from attempting to receive on one channel while it is transmitting on another channel. The timing of the super-frame 305 for all the nodes in a cluster is synchronized with the time master for that cluster providing the time reference.
In one embodiment of this invention each super-frame 305 is 60 ms in duration and is subdivided into six 10 ms first level time slots. The first five first level 10 ms time slots 310 are dedicated as first level FMN-to-FMN time slots and the sixth 10 ms first level time slot 315 is dedicated as the first level Contention Access Period (CAP) time slot. The purpose of the first level FMN-to-FMN time slot 310 is to provide a guaranteed time period during which a FMN 102 can transmit network packets to its neighboring FMN(s) 102 and to any mobile units (MMRs 101 or SMNs 103 ) which may be using it as their current parent.
The first level FMN-to-FMN time slot 310 is sub-divided into six second level time slots as illustrated in FIG. 4 . Each of these second level time slots has an assigned operation which will be executed by the FMN which is assigned the specific time slot. The second level Pre-guard time slots 440 allows for clock drift between network components, the assigned FMN does not transmit or receive during this second level time slot. The duration of the second level Pre-guard time slots 440 is fixed for a given network based on the clock accuracy of the components within the network. The second level PA Ramp time slot 445 is a time slot set aside to allow the Power Amplifier (PA) component of the FMN to reach full output power. The assigned FMN turns on its transmitter circuitry at the beginning of this second level time slot and then delays for the duration of the second level time slot without transmitting. The duration of the second level PA Ramp time slot 445 is fixed for a given network. The third second level time slot is the second level Primary time slot 450 . The assigned FMN uses the second level Primary time slot 450 to transmit queued network packets to its listening neighbors. Typically, a single first level Concatenated Data Frame 1700 , as shown in FIG. 17 , is used to transfer all the network packets. The duration of the second level Primary time slot is variable depending on the number of network frames in the assigned FMN's 102 outgoing queue. The second level Primary time slot 450 is followed by an second level Idle time slot 460 during which the FMN 102 can power down its transmitter to conserve power. The duration of the second level Idle time slot 460 is fixed for a given FMN 102 ; it may be adjusted during network deployment to provide a method to trade-off network formation/re-formation time with FMN power consumption. The second level Idle time slot 460 is followed by the second level Sync time slot 465 during which the assigned FMN 102 will transmit first level PHY frames 701 containing third level Sync frames 1800 . These Sync frames 1800 are used to aid scanning FMNs 102 or mobile nodes to find and synchronize with the network. The number of Sync frames 1800 to be sent in a given second level Sync time slot 465 may vary between subsequent super-frames depending on the durations of the second level Idle time slot 460 and the second level Primary time slot 450 . The second level Post-guard time slot 455 follows the second level Sync time slot 465 . The FMN 102 uses the second level Post-guard time slot 455 to turn off its transmitter and switch to receive mode for the next first level time slot 310 or 315 .
The purpose of the first level CAP time slot 315 is to provide an opportunity for other FMNs 102 to transmit Child Association request frames to a potential parent FMN 102 and to provide an opportunity for mobile nodes to transmit frames containing network packets into WMN 100 . The exact format for first level CAP time slot 315 depends on whether that particular bonded channel is dedicated to voice or data. For a given FMN 102 , one of the bonded channels is designated as the data channel due to the first level CAP time slot 315 being formatted into second level CAP data time slots 505 , as illustrated in FIG. 5 , and the other channel in the pair is designated as the voice channel due to the first level CAP time slot 315 being formatted into second level CAP voice time slots 605 , as illustrated in FIG. 6 .
As FIG. 5 also illustrates, the second level CAP data time slots are further comprised of a third level TX On Guard time slot 510 , a third level data Physical Layer (PHY) frame time slot 515 , a third level data Idle time slot 520 and a third level data TX Off Guard time slot 525 . Third level data TX On Guard time slot 510 and third level data TX Off Guard time slot 525 instruct the radio transmitting in the CAP slot time to turn its transmit circuitry on and off, respectively. Third level data Idle time slot 520 is the period of time after the transmitting radio has transmitted the last bit of the variable length third level data frame time slot 515 and before the beginning of third level data TX Off Guard time slot 525 .
Similarly FIG. 6 illustrates, the second level CAP voice time slots 605 are further comprised of a third level voice TX On Guard time slot 610 , a third level voice Physical Layer (PHY) frame time slot 615 , a third level voice Idle time slot 620 and a third level voice TX Off Guard time slot 620 . Third level voice TX On Guard voice time slot 610 and third level voice TX Off Guard time slot 625 instruct the radio transmitting in the CAP slot time to turn its transmit circuitry on and off, respectively [0034] FIG. 7 illustrates the general format of a first level PHY frame 701 . This frame format applies to both the third level Data Physical Layer (PHY) frame time slot 515 and the third level Voice Physical Layer (PHY) frame time slot 615 . A first level PHY frame 701 is further comprised of a second level PHY header frame 705 and a second level MAC frame 710 . The second level PHY header frame 705 further consists of a third level Preamble frame 715 , a third level Sync frame 720 and a third level Length frame 725 .
The third level Preamble frame 715 is encoded as a set of alternating 1 and 0 bits. The purpose of this third level frame is to provide a means for receiving radios to reliably obtain bit synchronization on the incoming bit stream.
The third level Sync frame 720 consists of a unique bit pattern which is preconfigured into all devices in WMN 100 . This third level frame is used by a receiving radio to obtain slot synchronization.
The third level Length frame 725 indicates to the receiver the number of bytes to expect in the second level MAC frame 710 .
The second level MAC frame 710 contains several third level frames which provide control and error correction functions. These third level frames include a third level Frame Control frame 730 , a third level Sequence Number frame 735 , a third level Destination Address frame 740 , a third level Source Address frame 745 , an third level Extended Header frame 750 , a third level MAC Payload frame 755 and a third level a cyclic redundancy check (CRC) frame 760 .
The third level Frame Control frame 730 provides several fourth level frames which inform the receiving radio of the purpose and format of the remainder of second level MAC frame 710 . The format and purpose of these fourth level frames are discussed in a subsequent section.
Third level Sequence Number frame 735 allows the acknowledgement of individual MAC packets and the filtering of duplicate packets. The value of this third level frame is set by the transmitter of the packet. Whenever a unicast acknowledgement is sent to indicate the status of the reception of this packet the value of the third level Sequence Number frame 735 in the Acknowledgement is set to this value.
Third level destination address frame 740 specifies the network address of the intended recipient of this packet. The length of this third level frame is determined by fourth level Destination Mode frame 845 , shown in FIG. 8 , of third level frame control frame 730 . In the preferred embodiment of this invention certain Destination Address values are reserved to indicate a packet is a broadcast packet and should therefore be processed by all receiving nodes.
Third level Source Address frame 745 specifies the network address of the transmitting unit. The length of this third level frame is determined by fourth level Source Mode frame 855 , shown in FIG. 8 , of third level Frame Control frame 730 .
The purpose of third level Extended Header(s) frame 750 is to provide a mechanism by which the sender can dynamically expand the MAC header with additional network information when needed. The format of this third level frame is described in a subsequent section.
The purpose and content of third level MAC Payload frame 755 is context dependent. The types of MAC packets which are supported on the WMN 100 are described in a subsequent section.
Third level CRC frame 760 provides the receiver with a method for detecting bits errors which may have occurred in the demodulation of the data bits in other third level frames 730 , 735 , 740 , 745 , 750 and 755 . This third level frame is 16 bits in length and is calculated using the standard CCITT CRC16 parameters.
Frame Control Field
The third level Frame Control frame 730 consists of several fourth level frames which inform the receiving radio of the purpose and format of the remainder of the second level MAC frame 710 . FIG. 8 illustrates the format of the third level Frame Control frame 730 . The fourth level frames within the third level Frame Control frame are shown in FIG. 8 and comprise the fourth level Frame Type frame 805 , the fourth level Security Enabled frame 810 , the fourth level Frame Pending frame 815 , the fourth level ACK Request frame 820 , the fourth level Intra-personal area network (Intra-PAN) frame 825 , the fourth level Extended Header indication flag frame 830 , the fourth level Scan frame 835 , the fourth level Retry frame 840 , the fourth level Destination Mode frame 845 , the fourth level Power Control frame 850 and the fourth level Source Mode frame 855 .
The fourth level Frame Type frame 805 indicates the purpose of this second level MAC frame 701 and therefore indicates the format of the third level MAC Payload frame 755 . The three fourth level MAC frame types used on this system are Single Data Frames, Concatenated Data Frames and Sync frames.
The fourth level Security Enabled frame 810 indicates whether or not MAC layer security is enabled.
The fourth level Frame Pending frame 815 indicates whether the sending unit has additional frames to send to the same destination address.
The fourth level ACK Request frame 820 indicates whether the sending unit is requesting a MAC layer acknowledgement of this frame.
The fourth level Intra-PAN frame 825 is reserved for future intra-PAN communications.
The fourth level Extended Header indication flag frame 830 is a flag which, when set to true, indicates whether or not one or more fourth level extended header frames follows the third level Source Address frame.
The fourth level Scan Notify frame 835 indicates whether or not the transmitter will be performing a scan operation in the next time slot or will be performing a normal transmission in the time slot.
The fourth level Retry frame 840 indicates whether or not the first level frame is a first transmission of the contained information or a retry of the transmission of the information.
The fourth level Destination Mode frame 845 indicates number of bits in the third level Destination Address frame 740 .
The fourth level Power Control frame 850 is used to indicate the power level at which the transmitter is transmitting the packet.
The fourth level Source Mode frame 855 indicates the number of bits in the third level Source Address frame 745 .
Extended Headers
The third level Extended Header frame 750 of the second level MAC frame 710 may consist of zero or more fourth level Extended Header frames 905 as illustrated in FIG. 9 . The presence or absence of the first fourth level Extended Header frame 905 is indicated by fourth level Extended Header indication frame 830 of third level Frame Control frame 730 . The presence or absence of each subsequent fourth level Extended Header 905 is indicated by the fifth level Next Extended Header frame 1005 in the header of the preceding fourth level Extended Header 905 frame. There are four different types of Extended Header frames 905 , each of which has a different format.
As illustrated in FIG. 10 , each fourth level Extended Header frame 905 consists of four generic elements. These elements are a fifth level Next Extended Header frame 1005 , a fifth level Extended Header Length frame 1010 , a fifth level Extended Header Type frame 1015 and a fifth level Extended Header Data frame 1020 .
The fifth level Next Extended Header frame 1005 indicates the presence or absence of an additional fourth level Extended Header frame 905 following this fourth level Extended Header frame 905 .
The fifth level Extended Header Length field 1010 indicates the number of octets in the fifth level Extended Header Data frame 1020 .
The fifth level Extended Header Type field 1015 indicates the purpose of this particular fourth level Extended Header frame 905 and the subsequent format of the fifth level Extended Header Data frame 1020 . There are five possible types of fourth level Extended Header frames which are Slot Info headers, Piggyback ACK headers, Piggyback Grant headers, Power Control headers and Future Grant headers.
The format of the first type of fourth level Extended Header frame 905 incorporates a fifth level Slot Info Extended Header frame 1100 , as illustrated in FIG. 11 . The contents of the fifth level Slot Info Extended Header Data frame 1100 consists of six sixth level frames: the ACK Map frame 1105 , the Channel frame 1110 , the Cycle Slot #/Foster Rotation frame 1115 , the Long Slot Number frame 1120 , the Time Master frame 1125 and the Time Hops frame 1130 .
The sixth level ACK Map frame 1105 is a bit mapped frame used to acknowledge multi-cast packets which have been received by the FMN 102 transmitting the Slot Info Extended Header.
The sixth level Channel frame 1110 indicates the logical channel on which this first level frame is being transmitted. This value, in combination with the slot and super-frame numbers can be used to synchronize to the transmitting unit hopping sequence if frequency hopping is being used.
The sixth level Cycle Slot #/Foster Rotation frame 1115 consists of three seventh level frames as illustrated in FIG. 12 . The first seventh level frame is the parent slot number frame 1205 which advertises whether the transmitting unit is a fostering MMR 101 or an FMN 102 and if it is the latter, this field indicates the slot number of the fostering MMRs 101 parent FMN 102 . The second seventh level frame is the Foster Rotation Number frame 1210 which advertises the future position of the voice and data CAP slots for a MMR which is being fostered. The final seventh level frame is the Slot Rotation Cycle frame 1215 which is used by a fostering MMR 101 to advertise which slot rotation schedule it is currently employing.
The sixth level Long Slot Number frame 1120 of a Slot Info Extended Header indicates the current value of the 16 bit slot number.
The sixth level Time Master frame 1125 of a Slot Info Extended Header indicates the ID of time master of the cluster to which the transmitting unit is a member.
The sixth level Time Hops frame 1130 indicates the number of hops to the Time Master of the cluster.
FIG. 13 illustrates the format of the second type of fourth level Extended Header frame 905 . This type of frame incorporates a fifth level Piggyback ACK Extended Header Data frame 1300 which is used by the transmitting unit to acknowledge a previously received unicast packet. A sixth level Sequence Number frame 1305 indicates the sequence number of the packet being acknowledged. A sixth level Address frame 1310 indicates the Source ID which was received in the packet being acknowledged. The sixth level receive signal strength indication (RSSI) frame 1315 indicates the receive signal strength at which the packet being acknowledged was received.
FIG. 14 illustrates the format of the third type of fourth level Extended Header frame 905 . This type of frame incorporates a fifth level Piggyback Grant Extended Header frame 1400 which is used by the transmitting unit to indicate which nodes are allowed to transmit in the next first level CAP time slot 315 . This arrangement provides a method by which bandwidth can be reserved for a unit which has multiple packets to send. Each of the four sixth level Address frames 1405 , 1410 , 1415 and 1420 will specify either a unicast address if the corresponding second level upstream time slot is reserved for a unicast transmission from a particular unit or to the special broadcast address if the corresponding second level CAP time slot is to be used as a CAP slot. In alternative embodiments, there may be more than four sixth level Address frames.
The fourth type of fourth level Extended Header frame 905 incorporates a fifth level Power Control Extended header frame which is not illustrated. This type of frame is used to communicate the current power setting of the transmitter. This is necessary since the power control algorithm may cause a unit to transmit at less than its nominal power setting and this information is needed to allow the receiving units to normalize the received signal strength readings associated with this unit. Since the receive power levels are used for position triangulation.
FIG. 15 illustrates the format of the fifth type of fourth level Extended Header frame 905 . This type of frame incorporates a fifth level Future Grant Extended Header frame 1500 which is used to reserve second level CAP time slots 315 for the upstream two slots in the future. Its primary purpose is to prevent an FMN 102 from transmitting in the next second level CAP time slot and missing its guaranteed grant coming up in the second level time slot after that. Each of the four sixth level Address frames 1505 , 1510 , 1515 and 1520 will specify either a unicast address if the corresponding second level CAP time slot is reserved for a unicast transmission from a particular unit or to the special broadcast address if the corresponding second level CAP time slot is to be used as a CAP slot. In alternative embodiments, there may be more than four sixth level Address frames.
MAC Packet Types
There are three possible formats for the third level MAC payload frame 755 used on WMN 100 . As mentioned above, the specific type of MAC packet is indicated in the fourth level Frame Type frame 805 . These three third level frame types are Single Data Frames, Concatenated Data Frames and Sync Frames.
FIG. 16 illustrates the format of a first level Single Data frame 1600 . The purpose of a first level Single Data frame 1600 is to transfer one and only one network packet. For this type of frame the third level MAC Payload frame 755 consists entirely of a single fourth level network packet frame 1605 . The third level Length field 725 will indicate the length of the fourth level network packet frame 1605 . The other third level fields of the first level Single Data frame 1600 will be used as described in the preceding sections.
FIG. 17 illustrates the format of a first level Concatenated Data frame 1700 . This frame type is used to transfer zero, one or more fourth level network packet frames 1605 between units. For this type of frame, the third level MAC Payload frame 755 consists of zero, one or more Length/Network Packet pairs. Each of these pairs will consist of a fourth level Length frame 1705 and a variable length fourth level Network Packet frame 1605 The fourth level Length frame 1705 indicates the number of octets in the corresponding fourth level Network Packet frame 1605 . The fourth level Network Packet frame 1605 contains the actual application layer information being transferred. The third level PHY Length frame 725 will indicate the number of octets in all of the fourth level Length/Network Packet pairs. The other third level frames of this type of first level packet frame are used as described in the preceding sections.
FIG. 18 illustrates the format of first level Sync frame 1800 . This type of frame may be sent during a first level FMN-to-FMN time slot 310 to facilitate adjacent FMNs 102 and mobile nodes in finding the network. The third level MAC Payload frame 755 for this first level frame type 1800 consists of a fourth level Time Master frame 1805 , a fourth level Slot Number frame 1810 and a fourth level Channel Number frame 1815 . The value of the fourth level Time Master frame 1805 is set to the network ID of the current time master of the transmitting unit. The value of the fourth level Slot Number frame 1810 is set to the current slot number for the cluster to which the transmitting unit belongs. The value of the fourth level Channel Number frame 1815 is set to the logical channel number on which the SYNC frame is being transmitted.
In alternative embodiments, more than one of any of the disclosed types of time slots and frames may be incorporated into the communications protocol formed with this invention.
In an emergency situation the need for reliable communications is paramount. For example, in a hazardous environment, such as underground, direct communications between two points is often made unreliable or impossible by destroyed infrastructure and/or blockage of line-of-sight by equipment and/or debris. By design, this invention creates a method by which the ad hoc mesh nodes automatically form and re-form in clusters to provide reliable network communications. This characteristic facilitates the natural creation of clusters of communication around FMN's 102 to provide an infrastructure and provides a method by which isolated pockets (clusters) of FMN's 102 can quickly reconnect with the main infrastructure. This invention further creates a protocol that provides a reliable wireless network formed by ad hoc mesh nodes. The communication protocol supports the creation and maintenance of a reliable network 100 including fixed and mobile nodes. This protocol provides methods by which mobile devices can communicate with other mobile devices and with Network Operations Center 105 while roaming freely through the network formed by the Fixed Mesh Nodes (FMN) 102 . The protocol supports voice, data and text communications in emergency and non-emergency modes. In addition this protocol provides methods by which each infrastructure node and mobile node can be monitored and managed at remote Network Operations Center 105 .
While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes and modifications may be made, and equivalents may be substituted for elements thereof without departing from the true scope of the present invention. In addition, many modifications may be made to adapt the teaching of the present invention to a particular situation without departing from its central scope. Therefore it is intended that the present invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out the present invention, but that the present invention include all embodiments falling within the scope of the appended claims. | Methods and apparatus for forming and maintaining an ad hoc mesh network suitable for reliable voice and data communications in underground, industrial and other hazardous environments. This invention includes support for cooperative negotiation of dedicated transmission bandwidth for all fixed network nodes, determination of network time synchronization without a pre-determined time master, discovery and merging of adjacent ad hoc mesh networks, and routing techniques for voice, data and network status packets which react instantaneously to network topology changes. Furthermore this invention provides a reliable communication network for mobile nodes carried by personnel and sensor nodes that are fixed or mobile that supports voice, data and tracking/situation awareness. A current application for this technology is a coal mine communication system with an operations center to dispatch, monitor and control coal mine operation including communication and location of mine personnel, and environmental conditions in the mine. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation of U.S. patent application Ser. No. 11/368,688 filed on Mar. 6, 2006 now abandoned which claims priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 60/662,957 filed on Mar. 18, 2005.
FIELD OF THE INVENTION
The present invention relates to intravascular devices used in medical treatment and procedures. More specifically, the present invention relates to a new class of organic high intensity X-ray contrast agents suitable for enhancing the imaging of medical devices, particularly polymeric medical devices and polymeric coatings being fabricated from a polymer with the contrast agent dispersed within, conjugated at one or both ends of the polymers, as well as the method of manufacture of such materials and devices.
DISCUSSION OF THE RELATED ART
Recently, transluminal prostheses have been widely used in the medical arts for implantation in blood vessels, biliary ducts, or other similar organs of living body. These prostheses are commonly known as stents and are used to maintain, open, or dilate tubular structures. An example of a commonly used stent is given in U.S. Pat. No. 4,733,665 filed by Palmaz on Nov. 7, 1985, which is hereby incorporated herein by reference. Such stents are often referred to as balloon expandable stents. Typically the stent is made from a solid tube of stainless steel, although other metallic materials have been utilized. Thereafter, a series of cuts are made in the wall of the stent. The stent has a first smaller diameter, which permits the stent to be delivered through the human vasculature by being crimped onto a balloon catheter. The stent also has a second, expanded diameter, upon application of a radially, outwardly directed force, by the balloon catheter, from the interior of the tubular shaped member.
However, one concern with such stents is that they are often impractical for use in some vessels such as the carotid artery. The carotid artery is easily accessible from the exterior of the human body, and is close to the surface of the skin. A patient having a balloon expandable stent made from stainless steel or the like, placed in their carotid artery, might be susceptible to severe injury through day-to-day activity. A sufficient force placed on the patient's neck could cause the stent to collapse, resulting in injury to the patient. In order to prevent this, self-expanding stents have been proposed for use in such vessels. Self-expanding stents act like springs and will recover to their expanded or implanted configuration after being crushed.
One type of self-expanding stent is disclosed in U.S. Pat. No. 4,655,771, which stent has a radially and axially flexible, elastic tubular body with a predetermined diameter that is variable under axial movement of the ends of the body relative to each other and which is composed of a plurality of individually rigid but flexible and elastic thread elements defining a radially self-expanding helix. This type of stent is known in the art as a “braided stent” and is so designated herein. Placement of such stents in a body vessel can be achieved by a device that comprises an outer catheter for holding the stent at its distal end, and an inner piston that pushes the stent forward once it is in position.
However, braided stents have many disadvantages. They typically do not have the necessary radial strength to effectively hold open a diseased vessel. In addition, the plurality of wires or fibers used to make such stents could become dangerous if separated from the body of the stent, where they could pierce through the vessel. Therefore, there has been a desire to have a self-expanding stent that is cut from a tube of metal, which is the common manufacturing method for many commercially available balloon-expandable stents. In order to manufacture a self-expanding stent cut from a tube, the alloy used would preferably exhibit superelastic or pseudoelastic characteristics at body temperature, so that it is crush recoverable.
The prior art makes reference to the use of alloys such as Nitinol (Ni—Ti alloy), which have shape memory and/or superelastic characteristics, in medical devices that are designed to be inserted into a patient's body. The shape memory characteristics allow the devices to be deformed to facilitate their insertion into a body lumen or cavity and then be heated within the body so that the device returns to its original shape. Superelastic characteristics, on the other hand, generally allow the metal to be deformed and restrained in the deformed condition to facilitate the insertion of the medical device containing the metal into a patient's body, with such deformation causing the phase transformation. Once within the body lumen, the restraint on the superelastic member can be removed, thereby reducing the stress therein so that the superelastic member can return to its original un-deformed shape by the transformation back to the original phase.
Alloys having shape memory/superelastic characteristics generally have at least two phases. These phases are a martensite phase, which has a relatively low tensile strength and which is stable at relatively low temperatures, and an austenite phase, which has a relatively high tensile strength and which is stable at temperatures higher than the martensite phase.
Shape memory characteristics are imparted to the alloy by heating the metal at a temperature above which the transformation from the martensite phase to the austenite phase is complete, i.e. a temperature above which the austenite phase is stable (the A f temperature). The shape of the metal during this heat treatment is the shape “remembered.” The heat-treated metal is cooled to a temperature at which the martensite phase is stable, causing the austenite phase to transform to the martensite phase. The metal in the martensite phase is then plastically deformed, e.g. to facilitate the entry thereof into a patient's body. Subsequent heating of the deformed martensite phase to a temperature above the martensite to austenite transformation temperature causes the deformed martensite phase to transform to the austenite phase, and during this phase transformation the metal reverts back to its original shape if unrestrained. If restrained, the metal will remain martensitic until the restraint is removed.
Methods of using the shape memory characteristics of these alloys in medical devices intended to be placed within a patient's body present operational difficulties. For example, with shape memory alloys having a stable martensite temperature below body temperature, it is frequently difficult to maintain the temperature of the medical device containing such an alloy sufficiently below body temperature to prevent the transformation of the martensite phase to the austenite phase when the device was being inserted into a patient's body. With intravascular devices formed of shape memory alloys having martensite-to-austenite transformation temperatures well above body temperature, the devices can be introduced into a patient's body with little or no problem, but they must be heated to the martensite-to-austenite transformation temperature, which is frequently high enough to cause tissue damage.
When stress is applied to a specimen of a metal such as Nitinol exhibiting superelastic characteristics at a temperature above which the austenite is stable (i.e. the temperature at which the transformation of martensite phase to the austenite phase is complete), the specimen deforms elastically until it reaches a particular stress level where the alloy then undergoes a stress-induced phase transformation from the austenite phase to the martensite phase. As the phase transformation proceeds, the alloy undergoes significant increases in strain but with little or no corresponding increases in stress. The strain increases while the stress remains essentially constant until the transformation of the austenite phase to the martensite phase is complete. Thereafter, further increases in stress are necessary to cause further deformation. The martensitic metal first deforms elastically upon the application of additional stress and then plastically with permanent residual deformation.
If the load on the specimen is removed before any permanent deformation has occurred, the martensitic specimen will elastically recover and transform back to the austenite phase. The reduction in stress first causes a decrease in strain. As stress reduction reaches the level at which the martensite phase transforms back into the austenite phase, the stress level in the specimen will remain essentially constant (but substantially less than the constant stress level at which the austenite transforms to the martensite) until the transformation back to the austenite phase is complete, i.e. there is significant recovery in strain with only negligible corresponding stress reduction. After the transformation back to austenite is complete, further stress reduction results in elastic strain reduction. This ability to incur significant strain at relatively constant stress upon the application of a load, and to recover from the deformation upon the removal of the load, is commonly referred to as superelasticity or pseudoelasticity. It is this property of the material which makes it useful in manufacturing tube cut self-expanding stents.
The prior art makes reference to the use of metal alloys having superelastic characteristics in medical devices that are intended to be inserted or otherwise used within a patient's body. See for example, U.S. Pat. No. 4,665,906 (Jervis) and U.S. Pat. No. 4,925,445 (Sakamoto et al.). However, the prior art has yet to disclose any suitable tube-cut self-expanding stents. In addition, many of the prior art stents lacked the necessary rigidity or hoop strength to keep the body vessel open. In addition, many of the prior art stents have large openings at their expanded diameter. The smaller the openings are on an expanded stent, the more plaque or other deposits it can trap between the stent and the vessel wall. Trapping these deposits is important to the continuing health of the patient in that it helps prevent plaque prolapse into the vessel, restenosis of the vessel it is implanted into, and strokes caused by the release of embolic particles into the bloodstream.
One additional concern with stents, and with other medical devices, is that they may exhibit reduced radiopacity under X-ray fluoroscopy. To overcome this problem, it is common practice to attach markers made from highly radiopaque materials to the stent, or to use radiopaque materials in plating or coating processes. Those materials are typically gold, platinum, or tantalum. The prior art makes reference to these markers or processes in U.S. Pat. No. 5,632,771 (Boatman et al), U.S. Pat. No. 6,022,374 (Imran), U.S. Pat. No. 5,741,327 (Frantzen), U.S. Pat. No. 5,725,572 (Lam et al), and U.S. Pat. No. 5,800,526 (Anderson et al). However, due to the relative position of these materials in the galvanic series versus the position of the base metal of the stent in the galvanic series, there is a certain challenge to overcome; namely, that of galvanic corrosion.
In addition, biodegradable stents and stents fabricated from polymeric materials that avoid the use of metallic materials must still be able to be visualized under X-ray fluoroscopy. For these types of devices a major challenge exists in how to impart/increase the radiopacity of these devices with out the use of radiopaque markers or coatings. The prior art makes reference to one such method in U.S. Pat. No. 4,935,019 (Papp), in which a radiopaque, polymeric composition suitable for printing onto surgical fabrics provides an X-ray detectable marker, said marker is obtained by dispersing a heavy metal salt such as barium sulfate in a liquid polymer carrier. In Papp, the barium sulfate has an average particle size greater than about 5 microns and is present in an amount of from about 15 to 90% by weight of total solids of said composition. Papp indicates that barium sulfate comprising from about 60 to 90% by weight of solids of said composition is preferred. However addition of barium sulfate in large percentage quantities such as this may affect the integrity of the base material, reducing strength, and adversely affecting other mechanical properties and characteristics. In biodegradable polymers, the impact of radiopaque additives may also affect properties such as degradation rates of bioabsorbable polymers, elasticity, while potentially adding the presence of stress risers in and around any localized concentration of barium sulfate particles within the material. Furthermore, inorganic contrast agents such as barium sulfate and zirconium oxide do not readily dissolve or do not easily disperse in organic solvents, which are commonly used to dissolve non-degradable and biodegradable polymers.
Accordingly, there is a need for a radiopaque material or agent that can be easily added to biostable polymeric and biodegradable polymeric materials which readily dissolves into the polymer so that the resulting composite material is adequately radiopaque and which will not adversely affect the material or mechanical properties of the material one desires to make radiopaque.
BRIEF SUMMARY OF THE INVENTION
The high intensity X-ray contrast agent in accordance with the present invention overcomes the disadvantages and shortcomings of what is currently available and satisfies the unmet needs of imaging medical devices, particularly non-metallic medical devices by maximizing the intensity of the x-ray contrast agent both through primary and secondary effects. Primary effects include incorporating the radiopaque element and maximizing the content of this element in the contrast agent through chemistry, while secondary effects include optimizing the location of the radiopaque element within the polymer. Essentially by selectively maximizing and incorporating the iodine content within and dispersed throughout the polymer one can tune the radiopacity of polymeric materials to levels previously not available. Moreover, the creation and optimization of this contrast agent allows for improved processing characteristics when combined with polymeric materials and as such may further reduce manufacturing costs while providing a polymeric material with improved high intensity radiopacity with a satisfactory degradation profile.
The present invention relates to a high intensity dendritic or star-shaped contrast agent suitable for use with implantable polymeric medical devices or for a polymeric coating of an implantable medical device. Multivalent hydroxyl or amine containing organic compounds such as pentaerythritol, bis-pentaerythritol glycerol, polyhydric mono- and di-saccharides, etc., can be used to react with an iodine containing aromatic compounds such as 2,3,5-triiodobenzoic acid to form such high iodine containing compounds. Each such compound may contain a multiple of three (3) iodine atoms, greatly intensifying the x-ray image of a medical device fabricated from a material containing such a compound. The iodine content in such a high intensity dendritic contrast agent may be as high as 85% using commercially available dendritic polyamine precursors.
In an exemplary embodiment of the present invention, the contrast agent may contain a multiplicity of iodine atoms or bromine atoms or a combination of both in a single molecule in order to enhance the x-ray image produced by dispersing the agent throughout the material that either the device will be fabricated from or applied as a coating to the device. In accordance with the present invention, the contrast agent can be constructed from any core of dendrimer containing free functional groups such as amine, hydroxyl, sulfhydryl, isocyanate, and result in a molecule containing a multiple of three (3) iodine or bromine or a combination of both atoms with each additional conjugation of small iodine or bromine containing building block, such as triiodobenzoic acid or as triiodobenzoic acid chloride. When constructed in this fashion, the contrast agent may be substantially soluble in common organic solvent such as acetone, dimethylacetamide (DMA), dimethylsulfoxide (DMSO), acetone, THF, 1,4-dioxane, DCM etc. and also has substantially good miscibility with common organic polymers such as PLGA, PLA etc. The contrast agent in accordance with the present invention can form a solid solution with a polymer matrix that can then form the basis of a medical device. The contrast agent in accordance with the present invention is substantially biocompatible and can be added to polymer or polymer mixtures, and/or inorganic/organic composite materials to enhance its X-ray image quality.
In another exemplary embodiment of the present invention, the contrast agent may be mixed with the bulk material by various means such as solvent casting, injection and/or compression molding in order to form a medical device or a coating for a medical device. The bulk form can then be processed to final size and shape by traditional fabrication methods. Alternatively, the polymeric coating with the contrast agent included can be applied to the surface of an implantable medical device employing traditional coating methods
In yet another exemplary embodiment of the present invention, selective incorporation of the contrast agent to a polymeric structure can be accomplished in a number of ways. By ensuring placement of the contrast agent in certain areas of the polymer structure and not in other areas, additional secondary improvements in radiopacity can be realized without affecting material and/or mechanical properties. One such example is incorporation of the contrast agent at the proximal and distal ends of the polymer chain. By utilizing methods such as orientrusion, which may provide for a high degree of molecular orientation of the polymer chains within the polymer, one can create a polymeric material with high intensity radiopacity at the select portions of the bulk material which would be significantly more radiopaque than the surrounding areas where the contrast agent was not present. Like wise the selective placement of the contrast agents in the coating material can provide one with secondary benefits similar to those obtained with selective placement of the contrast agents in the bulk material.
In yet another exemplary embodiment of the present invention, selective incorporation of the contrast agent to a polymeric structure can be accomplished through a covalent conjugation process at either of the distal and proximal end, or both ends of a biostable and/or biodegradable polymer chain. Such polymers with inherent radiopacity can be used to either build implantable devices or as a coating for an implantable medical device.
Furthermore the incorporation or application of biological and/or pharmaceutical agents with or onto the material can provide additional benefits when used in combination with the present invention, and as such is a further object of this invention. Compounds such as those identified below may be applied as coatings on these devices or incorporated within the polymer and may be used to deliver therapeutic and pharmaceutical agents which may include: anti-proliferative/antimitotic agents including natural products such as vinca alkaloids (i.e. vinblastine, vincristine, and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e. etoposide, teniposide), antibiotics (dactinomycin (actinomycin D) daunorubicin, doxorubicin and idarubicin), anthracyclines, mitoxantrone, bleomycins, plicamycin (mithramycin) and mitomycin, enzymes (L-asparaginase which systemically metabolizes L-asparagine and deprives cells which do not have the capacity to synthesize their own asparagine); antiplatelet agents such as G(GP) ll b /lll a inhibitors and vitronectin receptor antagonists; anti-proliferative/antimitotic alkylating agents such as nitrogen mustards (mechlorethamine, cyclophosphamide and analogs, melphalan, chlorambucil), ethylenimines and methylmelamines (hexamethylmelamine and thiotepa), alkyl sulfonates-busulfan, nirtosoureas (carmustine (BCNU) and analogs, streptozocin), trazenes-dacarbazinine (DTIC); anti-proliferative/antimitotic antimetabolites such as folic acid analogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine, and cytarabine), purine analogs and related inhibitors (mercaptopurine, thioguanine, pentostatin and 2-chlorodeoxyadenosine {cladribine}); platinum coordination complexes (cisplatin, carboplatin), procarbazine, hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen); anti-coagulants (heparin, synthetic heparin salts and other inhibitors of thrombin); fibrinolytic agents (such as tissue plasminogen activator, streptokinase and urokinase), aspirin, dipyridamole, ticlopidine, clopidogrel, abciximab; antimigratory; antisecretory (breveldin); anti-inflammatory: such as adrenocortical steroids (cortisol, cortisone, fludrocortisone, prednisone, prednisolone, 6α-methylprednisolone, triamcinolone, betamethasone, and dexamethasone), non-steroidal agents (salicylic acid derivatives i.e. aspirin; para-aminophenol derivatives i.e. acetaminophen; indole and indene acetic acids (indomethacin, sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac, and ketorolac), arylpropionic acids (ibuprofen and derivatives), anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids (piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone), nabumetone, gold compounds (auranofin, aurothioglucose, gold sodium thiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenic agents: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF); angiotensin receptor blockers; nitric oxide donors; antisense oligionucleotides and combinations thereof; cell cycle inhibitors, mTOR inhibitors, and growth factor receptor signal transduction kinase inhibitors; retenoids; cyclin/CDK inhibitors; HMG co-enzyme reductase inhibitors (statins); and protease inhibitors.
The use of compounds in conjunction with the present invention can provide distinct clinical advantages over existing therapies and/or devices. More specifically, compounds that are capable of causing lysis or degradation of the embolic debris can be incorporated into the filtering portion of the present invention. A factor to consider in the selection of such a compound is the origin of the debris be it thrombus, plaque, atheroma, or any other form representing an embolus. As the mesh and or pore size of the filtering aspect of the present invention decreases, more embolic material may become trapped in the filtering mechanism of the present invention, thereby increasing the load on the filtering portion. While small emboli (typically smaller than 100 microns) are not a major concern because of the body's natural ability to enzymatically degrade, digest or lyse the emboli, the embolic load on the filter itself can be overloaded and result in formation of a thrombus if the blood flow is significantly slowed to the point which allows for a thrombus formation. In this situation the incorporation or application of compounds, which can degrade trapped emboli, can be beneficial. Some exemplary suitable compounds may include: Tissue Plasminogen activator (TPA); Streptokinase (SK); Reteplase; Tenecteplase; Urokinase; Lanoteplase; Staphylokinase; and/or Nadroparin (anti-factor Xa). In addition, the filtering portion of the present invention may incorporate an antithrombotic and/or antithrombogenic agent to prevent the formation of a thrombus. Some exemplary compounds may include: Heparin; Fragmin (dalteparin, low MW Heparin); a monoclonal antibody such as ReoPro™ (abciximab, antiplatelet antibodies) Acenocoumarol; Anisindione; Dicumarol; Warfarin; Enoxaparin (Lovenox); Anagrelide (Agrylin); Indomethacin (Indocin); Dipyridamole; Clopidogrel; Aggrenox; and/or Coumadin. Furthermore, an affinity-binding compound may also be incorporated with the filtering aspect of the present invention by itself or in combination with other compounds. Affinity-binding compounds can promote the binding and/or adhesion of embolic material thus facilitating entrapment of embolic material and subsequent removal from the blood stream. Whether incorporated into the strut or membrane by methods such as chemical surface treatments, bombardment, placement into reservoirs, or in the case of polymeric struts and membranes, blended with the material itself, or by application of a coating to the struts and/or membranes with a compound, any identified compound or combination of identified compounds may be used. Furthermore any number of compounds may suggest themselves to one who is skilled in the art and may be utilized in connection with the present invention alone or in combination with other compounds.
The foregoing exemplary embodiments of the present invention provide a high intensity radiopaque contrast agent which may be used independently, for example as a coating or may be incorporated within a polymeric material to be subsequently fabricated into medical devices in accordance with the present invention. Moreover, the incorporation of drugs and/or agents may be combined with the high intensity contrast agent to realize additional synergistic benefits. As noted above, the incorporation of biological and/or pharmaceutically active agents with the present invention can be utilized for the additional purposes of preventing thrombus formation, promotion of binding, and degradation of thrombus, all of which provide a patient benefit.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the present invention as well as the preceding information may best be understood with reference to the subsequent detailed description taken in conjunction with the accompanying exemplary drawings in which:
FIG. 1 shows the coupling reaction between pentaerythritol and 2,3,5-triiodobenzoic acid and the reaction products wherein, SOCl 2 is the catalyst or activating agent, and THF/Hexane is the reaction medium or solvent for the reaction. The end product is a star-shaped high-density contrast agent.
FIGS. 2A and 2B show the coupling reaction between any of the polyamine dendrimers with 2,3,5-triiodobenzoic acid chloride to yield corresponding dendritic iodine-containing contrast agent (A); and a schematic drawing of a dendritic polyamine up to level 4 (B) as used in the present invention.
FIG. 3 shows the chemical structure of a level 1 polyamine dendritic derived high intensity iodine containing contrast agent.
FIG. 4 shows the chemical structure of a level 2 polyamine dendritic derived high intensity iodine containing contrast agent.
FIG. 5 shows the chemical structure of a Vacation 3 polyamine dendritic derived high intensity iodine containing contrast agent.
FIG. 6 shows the chemical structure of a Vacation 4 polyamine dendritic derived high intensity iodine containing contrast agent.
FIG. 7 shows the chemical structure of a commercially available water soluble contrast agent known in the art under the trade name Ultravist®.
FIG. 8 shows the reaction of an Fmoc-protected polyhydroxyl compound with 2,3,5-triiodobenzoic acid chloride to yield a protected high density iodine-containing initiator.
FIG. 9 shows the deprotection reaction of compound in FIG. 8 to yield the high density iodine containing amine initiator.
FIG. 10 shows transformation of amine-terminated initiator to a carboxyl-ended contrast agent.
FIG. 11 shows the reaction between the compound synthesized in FIG. 9 and lactide to yield a bioabsorbable polymer terminated with high density iodine contrast agent on one end (step 1 ); coupling reaction between carboxyl terminated initiator synthesized in FIG. 10 to yield a bioabsorbable polylactide (PLA) terminated with high density iodine contrast agent on both terminals (step 2 ).
FIGS. 12A and 12B show schematically the random orientation of polymer strands/chains in a matrix ( 12 A) and the aligned orientation of polymer strands/chains in a polymer that has undergone orientrusion ( 12 B).
FIG. 13 shows the chemical structure of exemplary dimers (glycolide, caprolactone, p-dioxanone, and trimethylene carbonate) used for making bioabsorbable polymers and/or copolymers.
FIG. 14 shows the reaction between the compound synthesized in FIG. 9 and glycolide (GA) to yield a bioabsorbable polymer terminated with high density iodine contrast agent on one end (step 1 ); coupling reaction between carboxyl terminated radiopaque compound synthesized in FIG. 10 to yield a bioabsorbable polyglycolide (PGA) terminated with high density iodine contrast agents on both ends (step 2 ).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1 , when reacting pentaerythritol ( 100 ) with 2,3,5-triiodobenzoic acid ( 200 ) in the presence of SOCl 2 (the catalyst) and THF/Hexane (the reaction medium), the resulting contrast agent ( 300 ) may have a high iodine content of 85%, almost twice as high as commercially available agents ( 50 ) such as those under the trade name Ultravist® as shown in FIG. 7 . In the reaction scheme, the number of benzoic acid moiety is denoted by m which is an integer between 1 and 4, depending on the completeness of the reaction. The number of unreacted hydroxyl group in the final compound is denoted by n, which is an integer between 0 and 3, depending again on the completeness of the reaction. The sum of m and n, however, should always be 4 which corresponds to the number of hydroxyl groups in the starting pentaerythritol. FIG. 2A shows an exemplary coupling reaction between a polyamine-terminated dendrimer with 2,3,5-triiodobenzoic acid chloride to yield a corresponding dendritic iodine containing contrast agents. In the reaction scheme, R′ denotes the portion of a dendrimer without the (NHR) n portion as depicted in FIG. 3 (level 1 dendrimer in which n=2), in FIG. 4 (level 2 dendrimer in which n=4), in FIG. 5 (level 3 dendrimer in which n=8), and in FIG. 6 (level 4 dendrimer in which n=16). In the reaction scheme, n is the total number of amine groups in a starting dendrimer that can be utilized in the coupling reaction. The total number of iodine atoms in each is 3n since each amine group after the reaction will yield 3 iodine atoms on the benzene ring. For example, for level 1 dendrimer in FIG. 3 , there are 2 amine groups in the starting dendrimer. The final iodine atom is 3×2=6 after the conjugation reaction. Likewise, FIG. 4 shows the conjugation reaction of a level 2 dendrimer and final dendritic contrast agent with 12 iodine atoms. FIG. 5 shows a level 3 dendritic contrasting agent with 24 iodine atoms. FIG. 6 shows a level 4 dendritic contrasting agent with 48 iodine atoms. FIG. 2 b shows a generic chemical structure of a dendritic compound used in the present invention with various levels denoted therein. Similarly dendrimers containing other functional groups such as carboxyl, hydroxyl, and sulfhydryl groups can also be used as the building blocks of high intensity contrast agents in accordance with this invention. As shown for the chemical structure of a commercially available contrast agent ( 50 ), known under the trade name Ultravist® in FIG. 7 , each such molecule only contains 3 iodine atoms covalently linked to the core benzene ring. The I—C bonds are demonstrated to be stable under physiological and irradiation conditions. The compound is mainly eliminated through renal dialysis.
The Iopromide compound in Ultravist® has multiple hydroxyl groups that make it soluble in water. Although the water solubility of this agent makes it suitable for use as an injectable contrast agent, it may not perform as well when used as a radiopaque coating or as a radiopaque additive in a polymer matrix. Such increase of side group makes the weight percentage of iodine in the molecule relatively low. In contrast, in accordance with the present invention, the linking of a multiple triiodobenzene ring structure to a core dendritic structure so the iodine content in each molecule is maximized can create a high intensity contrast agent suitable as an radiopaque additive as both a coating and an additive to a polymer matrix as well as other uses known to those skilled in the art. As shown in FIG. 8 , the simplest form of such a high iodine content contrast agent is synthesized through the reaction between a 9-fluorenylmethyl (Fmoc)-protected 1-amino-2,2-dihydroxymethyl-3-propanol ( 110 ) and three 2,3,5-triiodobenzoic acid chloride ( 210 ). In FIG. 8 , m denotes the number of the triiodobenzene moiety in the final contrast agent and is an integer between 1 and 3. N is the unreacted hydroxymethyl group in the final compound and is an integer between 0 and 2. The sum of m and n equals 3. When the reaction proceeds to completion, the resulting contrast agent ( 310 ) has an iodine content of about 74%, much higher than Ultravist's 48% ( 50 ). Additional advantages of a contrast agent in accordance with the present invention are that all raw materials are readily available and the coupling reactions generally have a high yield. Multiple layers of dendrimer cores may increase the cost, but this may be offset by ever-higher iodine content and reduced amount of the required agent in the medical device to achieve adequate image contrast. Increased molecule weight also reduces the mobility and potential of the contrast agent to leach out of the medical device.
Reacting a hydroxyl- or an amine-group containing compound and an iodine containing aromatic carboxylic acid or carboxylic acid chloride compound with a catalyst may be used to synthesize an iodine containing contrast agent. In accordance with the present invention this reaction is expanded further by using a bi-, tri- or tetra-hydroxyl containing compounds such as ethylene glycol, propylene glycol, glycerol, and pentaerythritol, bis-pentaerythritol to a single reactive contrast agent with a multiple number of iodine atoms, which may result in maximizing the radio-opacity of the molecule.
In-house research has showed that commercially available injectable contrast agents such as those under the trade name Ultravist® ( 50 ) (Ultravist is a Registered Trademark of Schering AG) (iopromide containing 3 iodine atoms in each Ultravist molecule) demonstrated comparable x-ray contrast to barium sulfate. The contrast agents in accordance with the present invention have up to two times (2×) more iodine atoms per unit weight of contrast agent, which may provide up to an estimated four times (4×) sharper contrast image quality. In addition, the proposed contrast agent is sparingly water-soluble and would not swell the polymer matrix of the medical device and thus better maintain the mechanical properties of a medical device. In addition to limiting the swelling, the leaching of the agent is also minimized.
In accordance with the present invention, multiple iodine molecules are built into a single contrast agent resulting in maximizing the radio-opacity of the contrast agent. Moreover, because good solubility of the contrast agent is present in common organic solvents, good miscibility may result with common polymers or polymer blends to form solid solutions. Enhanced mechanical strength of the bulk materials is maintained due to the elimination of crystalline additives which may result in stress risers, while relatively low water solubility ensures long residence time and degradation rate of the bulk material.
Additional modifications in accordance with the present invention such as use of various hydroxyl or amine containing functional molecules in the reaction may be beneficial. Typical examples include, ethylene glycol, propylene glycol, glycerol, pentaerythritol. Other functional group containing compounds such as carboxyl groups, may be used for the synthesis of the high intensity contrast agent compounds and naturally derived amine or polyhydric alcohols such as sorbitol, trehelose etc. may be used to construct such a contrast agent and in addition may provide good biocompatibility. As previously indicated, various processing methods such as solvent casting, dip coating, injection molding etc. may be used to mix the contrast agent and a bulk material.
In accordance with the present invention, compositions of a new class of polymeric high intensity X-ray contrast agents suitable for imaging implanted medical devices such as a drug eluting stent are formulated. Protected polyhydric alcohol or amine containing organic compounds commonly used in the synthesis of dendrimers may be used to react with an iodine containing aromatic compounds such as 2,3,5-triiodobenzoic acid to form such high iodine containing initiators. Each such initiator may contain a multiple of three (3) iodine atoms. Upon deprotection of Fmoc group, as shown in FIG. 9 , these iodine rich compounds possess a free amine group and can serve as an initiator for a ring opening reaction (ROP) of cyclic lactones such as lactide, glycolide etc. to form a bioabsorbable polymers. Other functional dimers such as a dilactams, lactone such as caprolactone, mixed dilactones, mixed cyclophosphoester, trimethylene carbonate (TMC), may also be used in the reaction. Optionally as shown in FIG. 10 , the amine end-capped initiator can be transformed to a carboxyl end-capped high iodine functional moiety by chloroacetic acid and later on used to cap the remaining end of a bioabsorbable polymer initiated with a iodine compound made in FIG. 9 . As shown in FIG. 11 , the initiator created in FIG. 9 is then used to initiate a cyclic dimmer through ROP to form a bioabsorbable polymer with high iodine content on one end ( 410 ). The resulting polymer can be further conjugated to a iodine containing compound created in FIG. 10 to yield a bioabsorbable polymer that have iodine atoms on both ends ( 510 ). This additional iodine containing moiety at the end of the polymer doubles the iodine content in the final bioabsorbable polymer and further enhances the x-ray image contrast. Similarly di-functional iodine rich compounds can be used in building other types of polymers such as polyurethanes and polyureas. The specific advantages of such a compound include but are not limited to: iodine containing bioabsorbable polymers which behave like bioabsorbable polymers used to make the matrices of a medical device such as a drug eluting stent; these compounds are soluble in common organic solvents; the molecular weight and other properties of such iodine containing bioabsorbable polymers can be adjusted to vary the degradation time, mechanical strength, and contrast intensity per polymer; the iodine-containing polymers in accordance with the present invention are miscible with the bulk materials used to construct a medical device, avoiding the change of degradation time and mechanical strength, and are not water-soluble and do not leach out during the manufacturing processes and initial implantation period.
FIGS. 12A and 12B show the orientation of polymer strands in a polymer matrix. Although the normal orientation of polymer chains in a polymer matrix ( 10 ) is random, one can impart a forces and/or processing conditions to create an alignment of the polymer chains within the structure ( 11 ) that may result in anisotropic material properties and may lead to improved material and/or mechanical properties. In accordance with the present invention, the polymers having high intensity contrast properties can be similarly processed to achieve the desired mechanical properties.
Similarly, other commonly used cyclic dimers as shown in FIG. 13 , for ring opening reactions such as glycolide (GA), caprolactone (CL), p-Dioxanone (DO), trimethylene carbonate (TMC) can all be used in the polymerizations alone or in mixture. Such dimers alone such as in FIG. 14 showing an ring opening reaction of glycolide (GA) to yield a bioabsorbable polyglycolide (PGA, 610 ), and end capping reaction with an iodine containing functional moiety to yield PGA ( 710 ) with 2× radiopaque density of 610. These cyclic dimmers may be used in combination with each other to adjust the physical and chemical properties of the final copolymers. These combinations are known to the skilled in the arts.
Additional embodiments and/or modifications include a series of functional iodine or bromine containing initiators used to initiate the ring opening reactions of a bioabsorbable polymer such as lactide, glycolide, caprolactone, or the mixture therein. Difunctional iodine or bromine rich compounds may serve as a building block of non-degradable polymers such as polyurethanes and polyureas. These polymeric structures can be further modified by having a biodegradable and/or biostable polymer containing multiple iodine atoms at one end or both ends of the polymer chains. This is accomplished by utilizing a process in accordance with the present invention for end capping an iodine or bromine containing biodegradable and/or biostable polymer at the end of the reaction to double the iodine atoms in the polymer chain. Moreover this process in accordance with the present invention may be used to form X-ray visible bulk material of a medical device using such iodine or bromine containing bioabsorbable polymers providing the necessary radiopacity. Alternately this process, in accordance with the present invention, for adding such iodine or bromine containing bioabsorbable polymers may be used to enhance the X-ray contrast intensity of the bulk of the medical device. Furthermore one is not limited to bioabsorbable polymers as this process, in accordance with the present invention, for using such iodine or bromine containing non-degradable or biostable polymers may be utilized to form X-ray visible bulk material of a medical device. The process in accordance with the present invention may also enhance the X-ray contrast intensity of the bulk of the medical device by adding such iodine or bromine containing nondegradable or biostable polymers to the bulk of the medical device.
A simple calculation of iodine content may show that with an iodine rich compound one has an iodine content of 72.7%. When incorporated into the final polymer with a degree of polymerization (DP) of 200 (molecular weight is ca. 30 KD), the iodine content in the final polymer is approximately 3.81%, which is adequate for visibility under normal x-ray operating conditions. If the final end-capping step in accordance with the present invention is used, the iodine content in the final polymer may be doubled to 7.25%, achieving a value much higher than 3.0% to 5.0% iodine content needed for acceptable x-ray opacity. Alternatively, the Molecular weight of the polymer may be doubled to around 60 Kilo Daltons (KD) without adversely affecting the radiopacity since the polymer would still have adequate X-ray opacity with the end-capping process of the present invention.
The method for introducing iodine or bromine atoms into each repeating monomer as disclosed in U.S. Pat. No. 6,475,477, (which is hereby incorporated by reference) may cause the property of bulk polymer to change as a result of iodine or bromine introduction which is distributed throughout the polymeric material. This series of patents were also limited to iodine or bromine containing polycarbonates. In comparison, the current method in accordance with the present invention clusters iodine atoms and/or selectively locates the atoms at one end or both ends of a polymer chain, leaving the bulk of the polymer chains intact for its role as a medical device and thereby not producing a change in the properties of the bulk material which may affect device performance.
This disclosed invention applies to both degradable and bioabsorbable polymer synthesis as well as non-degradable/biostable polymers. The incorporation of the high density radiopaque contrast agents can be added to a biostable polymer through grafting polymerization or plasma grafting processes. The X-ray opaque polymers may be further processed into different forms and shapes as medical devices providing the bulk material from which the end product or device is formed. The polymers may also be used as a polymeric coating or a drug release barrier for device drug combination products or to simply enhance the radiopacity of the device for which the material is coated upon or incorporated within.
The reaction between a hydroxyl group containing compound and an iodine containing aromatic compound may be processed for synthesizing an iodine containing contrast agent. This invention expands the concept further and used a protected bi-, tri- or tetra-hydroxyl containing compounds to make a functional initiator. Upon deprotection of Fmoc (9-fluorenylmethoxycarbonyl) as shown in FIG. 9 , the initiator can be used to initiate a ring opening reaction of cyclic lactones such as lactide, glycolide to form an iodine-containing polymer. Other commonly used protecting groups for amine and hydroxyl groups, other than Fmoc, such as Boc-, Z-, Ddz-, tert.-Butyl, Cbz, may be expressly used to substitute for Fmoc as a suitable protecting group in the reaction. The ring opening reaction is well researched and used in production of other biocompatible materials such as resorbable sutures. The final end-capping step as shown in FIGS. 11 and 13 is a variation of regular end capping of a methanol, to impart more iodine content of the bioabsorbable polymer.
In accordance with the present invention, multiple iodine molecules are built into a single initiator of a ring opening reaction. A bioabsorbable polymer contains a large number of iodine atoms without sacrificing the mechanical properties of the bulk materials, for example, such a bioabsorbable polymer may contain twice the number of iodine atoms by end capping with a derivative of the iodine containing functional initiator. Such iodine containing bioabsorbable polymer can be blended with regular bulk materials to form a medical device with much enhanced x-ray contrast and is non-leachable during the processing and initial period of implantation, ensuring desired degradation and biocompatibility. Furthermore, the contrast intensity of the medical device can be adjusted by varying the molecular weight and the percentage of the iodine-containing polymer in the matrices. This iodine introduction method may be used for synthesis of radiopaque non-degradable polymer as well in accordance with the present invention.
Modifications include use of various hydroxyl or amine containing functional molecules, which upon proper protection, can be used in the synthesis of the functional initiator. Upon deprotection, these functional initiators can be transformed into corresponding end capping iodine containing functional compounds. Any commonly monomers for bioabsorbable polymers such as lactide, glycolide, caprolactone, dioxanone, trimethylene carbonate, etc., or the combination of these monomers, can be used to construct the iodine-containing degradable polymers. Non-degradable polymers such as polyurethanes or polyureas may also be made more radiopaque using the same or similar chemistry such as chemical or plasma grafting reactions.
Although what has been shown and described is what is believed to be the most practical and preferred embodiment of the present invention, other forms of, and departures from the specific designs described and shown, will suggest themselves to those skilled in the art and may be used without departing from the spirit, scope or essential characteristics of the present invention. The present invention is not restricted or limited to the foregoing described embodiments, but rather should be constructed to cohere with all variations, combinations, and modifications that may fall within the scope of the appended claims. | In accordance with the present invention, a high intensity radiopaque contrast agent is disclosed. The agent may be coated on or incorporated within bulk materials, which may then be subsequently utilized to fabricate a radiopaque medical device. Primary effects through chemistry include higher radiopaque concentrations per unit weight of the radiopaque element or agent. Secondary effects include selective placement of the radiopaque elements which may further enhance the radiopacity of the device with reduced requirements of the radiopaque agent. Such a radiopaque contrast agent may be produced in various forms such as a dendrimer and/or incorporated as the end groups of polymeric chain. In addition one can incorporate biological and/or pharmaceutical agents in combination with the present invention. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the design, construction, and use of magnetic resonance (MR) imaging to identify areas within a patient where changes in a molecular environment are occurring, as from chemical concentration changes effected by medical procedures. The invention also describes a drug delivery device for targeted drug delivery into a patient using magnetic resonance (MR) imaging combined with conventional catheter placement techniques, particularly including neurosurgical or neuroradiologic techniques used in intracranial drug delivery.
2. Background of the Art
Although endoscopic, arthroscopic, and endovascular therapies have produced significant advances in healthcare, the diagnostic accuracy and clinical utility of these procedures is ultimately "surface limited" by what the surgeon can see through the device itself or otherwise visualize during the course of the procedure. Magnetic Resonance (MR) imaging, by comparison, overcomes this limitation by enabling the surgeon to non-invasively visualize tissue planes beyond the surface of the tissue under direct evaluation. Moreover, MR imaging enables differentiation of normal from abnormal tissues, and can display critical structures such as blood vessels in three dimensions. Thus, high-speed MR-guided therapy offers an improved opportunity to maximize the benefits of minimally invasive procedures. Prototype high-speed MR imagers which permit continuous real-time visualization of tissues during surgical and endovascular procedures have already been developed. Recent publications in the medical literature have described a number of MR-guided interventions including needle biopsies, interstitial laser therapy, interstitial cryotherapy and interstitial focused ultrasound surgery.
The standard current procedure for drug treatment of various focal neurological disorders, neurovascular diseases, and neurodegenerative processes requires neurosurgeons or interventional neuroradiologists to deliver drug agents by catheters or other tubular devices directed into the cerebrovascular or cerebroventricular circulation, or by direct injection of the drug agent, or cells which biosynthesize the drug agent, into targeted intracranial tissue locations. The blood-brain barrier and blood-cerebrospinal fluid barrier almost entirely exclude large molecules like proteins, and control entry of smaller molecules. Small molecules (<200 daltons) which are lipid-soluble, not bound to plasma proteins, and minimally ionized, such as nicotine, ethanol, and some chemotherapeutic agents, readily enter the brain. Water soluble molecules cross the barriers poorly or not at all. Delivery of a drug into a ventricle bypasses the blood-brain barrier, and allows for a wide distribution of the drug in the brain ventricles, cisterns, and spaces due to the normal flow pathways of cerebrospinal fluid in the brain. However, following intracerebroventricular injection, many therapeutic drug agents, particularly large-molecular weight hydrophobic drugs, fail to reach their target receptors in brain parenchyma because of metabolic inactivation and inability to diffuse into brain tissues, which may be up to 18 mm from a cerebrospinal fluid surface.
To optimize a drug's therapeutic efficacy, it should be delivered to its target tissue at the appropriate concentration. A number of studies reported in the medical literature, for example, Schmitt, Neuroscience, 13, 1984, pp. 991-1001, have shown that numerous classes of biologically active drugs, such as peptides, biogenic amines, and enkephalins have specific receptor complexes localized at particular cell regions of the brain. Placing a drug delivery device directly into brain tissue thus has the notable advantage of initially localizing the injected drug within a specific brain region containing receptors for that drug agent. Targeted drug delivery directly into tissues also reduces drug dilution, metabolism and excretion, thereby significantly improving drug efficacy, while at the same time it minimizes systemic side-effects.
An important issue in targeted drug delivery is the accuracy of the navigational process used to direct the movement of the drug delivery device. Magnetic resonance imaging will likely play an increasingly important role in optimizing drug treatment of neurological disorders. One type of MR unit designed for image-guided therapy is arranged in a "double-donut" configuration, in which the imaging coil is split axially into two components. Imaging studies are performed with this system with the surgeon standing in the axial gap of the magnet and carrying out procedures on the patient. A second type of high-speed MR imaging system combines high-resolution MR imaging with conventional X-ray fluoroscopy and digital subtraction angiography (DSA) capability in a single hybrid unit. Both of these new generations of MR scanners provide frequently updated images of the anatomical structures of interest. This real-time imaging capability makes it possible to use high-speed MR imaging to direct the movement of catheters and other drug delivery vehicles to specific tissue locations, and thereby observe the effects of specific interventional procedures.
A prerequisite for MRI-guided drug delivery into the brain parenchyma, cerebral fluid compartments, or cerebral vasculature is the availability of suitable access devices. U.S. Pat. No. 5,571,089 to Crocker et al. and U.S. Pat. No. 5,514,092 to Forman et al. disclose endovascular drug delivery and dilatation drug delivery catheters which can simultaneously dilate and deliver medication to a vascular site of stenosis. U.S. Pat. No. 5,171,217 to March describes the delivery of several specific compounds through direct injection of microcapsules or microparticles using multiple-lumen catheters, such as disclosed by Wolinsky in U.S. Pat. No. 4,824,436. U.S. Pat. No. 5,580,575 to Unger et al. discloses a method of administering drugs using gas-filled liposomes comprising a therapeutic compound, and inducing the rupture of the liposomes with ultrasound energy. U.S. Pat. No. 5,017,566 to Bodor discloses redox chemical systems for brain-targeted drug delivery of various hormones, neurotransmitters, and drugs through the intact blood-brain barrier. U.S. Pat. No. 5,226,902 to Bae et al. and U.S. Pat. No. 4,973,304 to Graham et al. disclose drug delivery devices, in which biologically active materials present within a reversibly permeable hydrogel compartment can be delivered into tissues by various endogenous and exogenous stimuli. U.S. Pat. No. 5,167,625 to Jacobsen et al. discloses an implantable drug delivery system utilizing multiple drug compartments which are activated by an electrical circuit. U.S. Pat. No. 4,941,874 to Sandow et al. discloses a device for the injection of implants, including drug implants that may used in the treatment of diseases. U.S. Pat. Nos. 4,892,538, 4,892,538, 5,106,627, 5,487,739 and 5,607,418 to Aebischer et al. disclose implantable drug therapy systems for local delivery of drugs, cells and neurotransmitters into the brain, spinal cord, and other tissues using delivery devices with a semipermeable membrane disposed at the distal end. U.S. Pat. No. 5,120,322 to Davis et al. describes the process of coating the surface layer of a stent or shunt with lathyrogenic agent to inhibit scar formation during reparative tissue formation, thereby extending exposure to the drug agent. U.S. Pat. Nos. 4,807,620 to Strul and 5,087,256 to Taylor are examples of catheter-based devices which convert electromagnetic Rf energy to thermal energy. Technology practiced by STS Biopolymers (Henrietta, N.Y.) allows incorporation of pharmaceutical agents into thin surface coatings during or after product manufacture. The invention disclosed by STS Biopolymers allows for the drugs to diffuse out of the coating at a controlled rate, thereby maintaining therapeutic drug levels at the coating surface while minimizing systemic concentrations. The coating can incorporate natural or synthetic materials that act as antibiotics, anticancer agents, and antithrombotics, according to the issued patent. U.S. Pat. No. 5,573,668 to Grosh et al. discloses a microporous drug delivery membrane based on an extremely thin hydrophilic shell. U.S. Pat. No. 5,569,197 to Helmus et al. discloses a drug device guidewire formed as a hollow tube suitable for drug infusion in thrombolytic and other intraluminal procedures.
A number of articles published in the medical literature, for example, Chandler et al., Ann. N.Y. Acad. Sci., 531, 1988, pp. 206-212, Bouvier et al., Neurosurgery 20(2), 1987, pp. 286-291, Johnston et al., Ann. N.Y. Acad. Sci., 531, 1988, pp. 57-67, and Sendelbeck et al., Brain Res., 328, 1985, pp. 251-258 describe implantable pump systems designed for continuous or episodic delivery of therapeutic drugs into the central nervous system via systemic, intrathecal, intracerebroventricular, and intraparenchymal injection or infusion.
The patented inventions referenced above provide useful methods for introducing, delivering, or applying a drug agent to a specific target tissue, but each invention also has inherent problems. For example, some catheter systems which provide endovascular drug delivery require temporary blocking of a segment of the vessel, thereby transiently disrupting brain perfusion. Microencapsulated coatings on catheters permit longer exposure of the tissue to the drug agent, but the physical limitations imposed by microcapsules restrict the volume and concentration of drug that can be effectively applied to any tissue area. Exposed coatings on catheters which contain drug agents usually require some type of sheath that must be removed from the catheter before the drug can be released from the coating. The sheath and any catheter components required to physically manipulate the sheath greatly increase the profile of the catheter, and thereby limit the variety of applications for which the drug delivery system can be employed. Furthermore, the binders or adhesives used in catheter coatings may themselves significantly dilute the concentration of the therapeutic agent Finally, thermal and light energy required to melt and bond coatings such as macroaggregated albumin, to reduce tissue mass by ablation, and to inhibit restenosis by cytotoxic irradiation may also cause damage to blood vessels.
U.S. Pat. No. 5,470,307 to Lindall discloses a low-profile catheter system with an exposed coating containing a therapeutic drug agent, which can be selectively released at remote tissue site by activation of a photosensitive chemical linker. In the invention disclosed by Lindall, the linker is attached to the substrate via a complementary chemical group, which is functionalized to accept a complementary bond to the therapeutic drug agent. The drug agent is in turn bonded to a molecular lattice to accommodate a high molecular concentration per unit area and the inclusion of ancillary compounds such as markers or secondary emitters.
Although U.S. Pat. No. 5,470,307 to Lindall describes significant improvements over previous catheter-based drug delivery systems, there are nonetheless some problems. First, in common with other currently used endovascular access devices, such as catheters, microcatheters, and guidewires, the catheter tip is difficult to see on MRI because of inadequate contrast with respect to surrounding tissues and structures. This makes accurate localization difficult and degrades the quality of the diagnostic information obtained from the image. Also, the mere observation of the location of the catheter in the drug delivery system does not reliably or consistently identify the position, movement and/or efficient delivery of drugs provided through the system. Thus, one objective of this invention is to provide for an MR-compatible and visible device that significantly improves the efficacy and safety of drug delivery using MR guidance.
Any material that might be added to the structure of a pliable catheter to make it MR visible must not contribute significantly to the overall magnetic susceptibility of the catheter, or imaging artifacts could be introduced during the MR process. Moreover, forces might be applied to such a catheter by the superconducting magnetic manipulation coils of a nonlinear magnetic stereotaxis system which might be used in the practice of the present invention. In either case, the safety and efficacy of the procedure might be jeopardized, with resulting increased risk to the patient. Also, an MR-visible catheter must be made of material that is temporally stable and of low thrombolytic potential if it is to be left indwelling in either the parenchymal tissues or the cerebral vasculature. Examples of such biocompatible and MR-compatible materials which could be used to practice the invention include elastomeric hydrogel, nylon, teflon, polyamide, polyethylene, polypropylene, polysulfone, ceramics, cermets steatite, carbon fiber composites, silicon nitride, and zirconia, plexiglass, and poly-ether-ether-ketone.
It is also important that drug delivery devices used under MR guidance are MR-compatible in both static and time-varying magnetic fields. Although the mechanical effects of the magnetic field on ferromagnetic devices present the greatest danger to patients through possible unintended movement of the devices, tissue and device heating may also result from radio-frequency power deposition in electrically conductive material located within the imaging volume. Consequently, all cables, wires, and devices positioned within the MR imager must be made of materials that have properties that make them compatible with their use in human tissues during MR imaging procedures. Many materials with acceptable MR-compatibility, such as ceramics, composites and thermoplastic polymers, are electrical insulators and do not produce artifacts or safety hazards associated with applied electric fields. Some metallic materials, such as copper, brass, magnesium and aluminum are also generally MR-compatible, viz. large masses of these materials can be accommodated within the imaging region without significant image degradation.
Guidewires for the catheter or drug delivery system are usually made of radiopaque material so that their precise location can be identified during a surgical procedure through fluoroscopic viewing. Exemplary of guidewires used under X-ray viewing is the guidewire disclosed by LeVeen, U.S. Pat. No. 4,448,195, in which a radiopaque wire can be identified on fluoroscopic images by metered bands placed at predetermined locations. The U.S. Pat. No. 4,922,924, awarded to Gambale et al. discloses a bifilar arrangement whereby radiopaque and radiotransparent filaments are wrapped on a mandril to form a bifilar coil which provides radiopaque and radiotransparent areas on the guide wire. U.S. Pat. No. 5,375,596 to Twiss et al. discloses a method for locating catheters and other tubular medical devices implanted in the human body using an integrated system of wire transmitters and receivers. U.S. Pat. No. 4,572,198 to Codrington also provides for conductive elements, such as electrode wires, for systematically disturbing the magnetic field in a defined portion of a catheter to yield increased MR visibility of that region of the catheter. However, the presence of conductive elements in the catheter also introduces increased electronic noise and the possibility of Ohmic heating, and these factors have the overall effect of degrading the quality of the MR image and raising concerns about patient safety. Thus, in all of these examples of implantable medical probes, the presence of MR-incompatible wire materials causes large imaging artifacts. The lack of clinically adequate MR visibility and/or imaging artifact contamination caused by the device is also a problem for most commercially available catheters, microcatheters and shunts.
MRI enables image-guided placement of a catheter or other drug delivery device at targeted intracranial loci. High-resolution visual images denoting the actual position of the drug delivery device within the brain would be extremely useful to the clinician in maximizing the safety and efficacy of the procedure. Drug delivery devices, such as catheters, that are both MR-visible and radio-opaque could be monitored by both X-ray fluoroscopy and MR imaging, thus making intra-operative verification of catheter location possible.
Initial attempts to position and visualize endovascular devices in MR imaging were based on passive susceptibility artifacts produced by the device when exposed to the MR field. Magnetic susceptibility is a quantitative measure of a material's tendency to interact with and distort an applied magnetic field. U.S. Pat. No. 4,827,931, to Longmore and U.S. Pat. Nos. 5,154,179 and 4,989,608 to Ratner disclose the incorporation of paramagnetic material into endovascular devices to make the devices visible under MR imaging. U.S. Pat. No. 5,211,166 to Sepponen similarly discloses the use of surface impregnation of various "relaxants", including paramagnetic materials and nitrogen radicals, onto surgical instruments to enable their MR identification. However, these patents do not provide for artifact-free MR visibility in the presence of rapidly alternating magnetic fields, such as would be produced during echo-planar MR imaging pulse sequences used in real-time MR guidance of intracranial drug delivery procedures. Nor do these patents teach a method for monitoring with MR-visible catheters the outcomes of therapeutic interventions, such as, for example, drug delivery into brain tissues, cerebral ventricles, or subarachnoid space. Ultrafast imaging sequences generally have significantly lower spatial resolution than conventional spin-echo sequences. Image distortion may include general signal loss, regional signal loss, general signal enhancement, regional signal enhancement, and increased background noise. The magnetic susceptibility artifact produced by the device should be small enough not to obscure surrounding anatomy, or mask low-threshold physiological events that have an MR signature, and thereby compromise the physician's ability to perform the intervention. These relationships will be in part dependent upon the combined or comparative properties of the device, the particular drug, and the surrounding environment (e.g., tissue).
An improved method for passive MR visualization of implantable medical devices has recently been disclosed by Werne (Ser. No. 08/554,446) ITI Medical Technologies (Application Pending). This invention minimizes MR susceptibility artifacts, and controls eddy currents in the electromagnetic scattering environment, so that a bright "halo" artifact is created to outline the device in its approximately true size, shape, and position. In the method of the invention disclosed by ITI, an ultra thin coating of conductive material comprising 1-10% of the theoretical skin depth of the material being imaged--typically about 250,000 angstroms--is applied. By using a coating of 2,000-25,000 angstroms thickness, ITI has found that the susceptibility artifact due to the metal is negligible due to the low material mass. At the same time, the eddy currents are limited due to the ultra-thin conductor coating on the device. A similar method employing a nitinol wire with Teflon coat in combination with extremely thin wires of a stainless steel alloy included between the nitinol wire and Teflon coat, has recently been reported in the medical literature by Frahm et al., Proc. ISMRM, 3, 1997, p. 1931.
Exemplary of methods for active MR visualization of implanted medical devices is U.S. Pat. No. 5,211,165 to Dumoulin et al., which discloses an MR tracking system for a catheter based on transmit/receive microcoils positioned near the end of the catheter by which the position of the device can be tracked and localized. Applications of such catheter-based devices in endovascular and endoscopic imaging have been described in the medical literature, for example, Hurst et al., Mag. Res. Med., 24, 1992, pp. 343-357, Kantor et al., Circ. Res., 55, 1984, pp. 55-60; Kandarpa et al., Radiology, 181, 1991, pp. 99; Bornert et al., Proc. ISMRM, 3, 1997, p. 1925; Coutts et al., Proc. ISMRM, 3, 1997, p. 1924; Wendt et al., Proc, ISMRM, 3, 1997, p. 1926; Langsaeter et al., Proc. ISMRM, 3, 1997, p. 1929; Zimmerman et al., Proc. ISMRM, 3, 1997, p. 1930; and, Ladd et al., Proc. ISMRM, 3, 1997, p. 1937.
In the treatment of neurological diseases and disorders, targeted drug delivery can significantly improve therapeutic efficacy, while minimizing systemic side-effects of the drug therapy. Image-guided placement of the tip of a drug delivery catheter directly into specific regions of the brain can initially produce maximal drug concentration close to the loci of tissue receptors following injection of the drug. At the same time, the limited distribution of drug injected from a single catheter tip presents other problems. For example, the volume flow rate of drug delivery must be very low in order to avoid indiscriminate damage to brain cells and nerve fibers. Delivery of a drug from a single point source also limits the distribution of the drug by decreasing the effective radius of penetration of the drug agent into the surrounding tissue receptor population. Another aspect of this invention is therefore to overcome these inherent limitations of single point source drug delivery by devising a multi-lumen catheter with multiple drug release sources which effectively disperse therapeutic drug agents over a brain region containing receptors for the drug, or over an anatomically extensive area of brain pathology.
SUMMARY OF THE INVENTION
Magnetic Resonance Imaging (MRI) is used in combination with 1) an MR observable delivery device or 2) an MR observable medical device which can alter a water based molecular environment by performed medical operations, the delivery device or medical device being used in the presence of MR observable (in water, body fluid or tissue) compound(s) or composition(s). MRI images are viewed with respect to a molecular environment to determine the position of the delivery or medical device (hereinafter collectively referred to as the "delivery device" unless otherwise specifically identified) and changes in the environment where the delivery device is present as an indication of changes in the molecular environment. As the delivery of material from the delivery device is the most significant event within the molecular environment in the vicinity of the delivery area, the changes in the molecular environment are attributable to the delivery of the MR observable compounds or compositions. Changes in signal intensity within the MR images reflect the changes in the molecular environment and therefore track the location of delivered materials, and are indicative of delivery rates and delivery volumes in viewable locations. With the medical device, chemical composition within the molecular environment may also be altered as by the removal of deposits of certain materials into the liquid (water) environment, where those materials can alter the MR response. Some materials which may be removed by medical procedures will not affect the MR response, such as calcium, but fatty materials may. Additionally, medical treatments which stimulate natural activities of chemical producing systems (e.g., the glands, organs and cells of the body which generate chemicals such as enzymes and other chemicals with specific biological activity [e.g., dopamine, insulin, etc.] can be viewed under direct MR observation and any changes in chemical synthetic activity and/or delivery can be seen because of molecular environment changes which occur upon increased synthetic activity.
One recently established method of reading the data obtained from the MR imaging is technically founded upon existing knowledge of Apparent Diffusion Coefficients (ADC) in particular regions of the body. There is significant published literature with respect to ADC values for specific tissues in various parts of animals, including various tissues of humans (e.g., Joseph V. Hajnal, Mark Doran, et al., "MR Imaging of Anisotropically Restricted Diffusion of Water in the Nervous System: Technical, Anatomic, and Pathological Considerations," Journal of Computer Assisted Tomography, 15(1): 1-18, January/February, 1991, pp. 1-18). It is also well established in the literature that loss of tissue structure through disease results in a decrease of the ADC, as the tissue becomes more like a homogeneous suspension. Clinical observations of changes in diffusion behavior have been made in various tissue cancers, multiple sclerosis, in stroke, where the reduction in diffusion precedes the increase in T2, and in epilepsy. Thus, ADC values are specific for specific types of tissues. Accordingly, as different drugs/chemicals are introduced into a tissue volume under MR observation, the ADC resulting from each drug/chemical interaction can be observed and the change in the ADC can be determined for that drug/chemical interaction with that particular tissue/drug environment.
While the ADC is the preferred means within the present invention of mapping the delivery of drug in tissue, other embodiments of the invention allow for additional tissue contrast parameters to track the delivery of a drug into tissue. In other words, the delivery of a drug into tissue will cause other MRI-observable changes which can be mapped (as is done for ADC) and which can be used to spatially track the delivery and extent of a drug into a tissue. While some of these observations may be larger in magnitude than others, any of the effects can be used as a tracking mechanism.
The tissue contrast changes apparent on an MR image can arise from ADC, from alterations in the B0 magnetic field (often referred to as magnetic susceptibility or ΔB0 produced by the presence of a substance in said tissue), from alterations in local tissue T1 relaxation times, from local T2 relaxation times, from T2* relaxation times (which can be created by susceptibility differences), from the magnetization transfer coefficients (MTC is an effect produced by local communication between free water protons and those of nearby macromolecular structures), from the ADC anisotropy observed in oriented matter, and also from local differences in temperature which will affect in varying degrees all of the included tissue contrast parameters. In addition, the delivery of drug can also be tracked from magnetic filed frequency shifts caused by the drug or arising from agents added with unique frequency shifts from those of the local protons (such as that created from F-19 or fluorine-19 agents found in or added to the drug).
MR imaging of the alterations in the B0 magnetic field (also known as imaging of the local magnetic susceptibility) can reveal the spatial distribution of a drug from the interaction of the drug with the otherwise homogeneous magnetic field found in MRI. To enhance the alterations in the magnetic field B0 caused by the drug, small amounts of a B0-altering added agents can be added to the drug during delivery. This can include iron oxide particles, or materials comprising lanthanide-, manganese-, and iron-chelates. In addition, vehicles containing differing gases (N2, O2, CO2) will also alter the local magnetic field and thus produce a magnetic susceptibility effect which can be imaged.
The invention includes a device and a method for MR-guided targeted drug delivery into a patient, such as intracranial drug delivery, intraspinal drug delivery, intrarenal drug delivery, intracardial drug delivery, etc. The MR-visible drug delivery device is guided to target entrance points to the patient such as periventricular, intracerebroventricular, subarachnoid, or intraparenchymal tissues magnetic resonance imaging, or conventional methods of neurosurgical or neuroradiologic catheter manipulation. The drug delivery device has a linearly arranged array of radiopaque and MR-visible markers disposed at its distal end to provide easily identifiable reference points for trackability and localization under susceptibility MR imaging and X-ray fluoroscopy guidance. Additionally, active MR visualization of the drug delivery device is achieved by means of RF microcoils positioned along the distal axis of the device. MR visibility can be variably adjustable based on requirements related to degree of signal intensity change for device localization and positioning, enhancement along the shaft of the device, enhancement around the body of the device, visibility of the proximal and distal ends of the device, degree of increased background noise associated with device movement, and other factors which either increase or suppress background noise associated with the device. Since the tip of the drug delivery device can be seen on MR and X-ray images and thus localized within the brain, the multiple point source locations of drug delivery are therefore known and can be seen relative to the tip or the shaft of the device.
Targeted delivery of drug agents is performed utilizing MR-compatible pumps connected to variable-length concentric MR-visible dialysis probes each with a variable molecular weight cut-off membrane, or by another MR-compatible infusion device which injects or infuses a diagnostic or therapeutic drug solution. Imaging of the injected or infused drug agent is performed by MR diffusion mapping using the RF microcoils attached to the distal shaft of the injection device, or by imaging an MR-visible contrast agent that is injected or infused through the walls of the dialysis fiber into the brain. The delivery and distribution kinetics of injections or infusions of drug agents at rates between 1 ul/min to 1000 ul/min are monitored quantitatively and non-invasively using real-time contrast-enhanced magnetic susceptibility MR imaging combined with water proton directional diffusion MR imaging.
One aspect of the present invention is to provide a non-invasive, radiation-free imaging system for tracking a drug delivery device to a target intracranial location.
Another aspect of the present invention is to provide an imaging system for visualizing the distal tip of the drug delivery device at the target intracranial location.
A third aspect of this invention is to provide for an MR-compatible and visible device that significantly improves the efficacy and safety of intracranial drug delivery using MR guidance.
A fourth aspect of the present invention is to provide for interactive MR imaging of injected or infused MR-visible drug agents superimposed upon diagnostic MR images of the local intracranial anatomy.
A fifth aspect of the present invention is provide an MR imaging method for quantitative monitoring of the spatial distribution kinetics of a drug agent injected or infused from a drug delivery device into the central nervous system, in order to determine the efficacy of drug delivery at various intracranial target sites.
A sixth aspect of the present invention is to provide an MR imaging method to evaluate how the spatial distribution kinetics of a drug agent injected or infused from a drug delivery device into the central nervous system is influenced by infusion pressure, flow rate, tissue swelling and other material properties of the brain, and by the physicochemical nature of the drug agent infused.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of the drug delivery device illustrating an exemplary method of practicing the present invention.
FIG. 2 is a cross-sectional view of the preferred embodiment of the drug delivery device, shown on a platform located above an anatomically targetted site in the brain. The view shows the disposition of a pump or reservoir containing the injectable material in relation to the other components of the device.
FIGS. 3A and 3B illustrate the preferred arrangement of the individual delivery catheters within the assembly of the multi-lumen delivery device.
FIG. 4 is a further cross-sectional view of the preferred embodiment of the device which shows the disposition of RF microcoil elements along the distal shaft of the delivery device.
FIG. 5 is an elevated cross-sectional view of the preferred embodiment of the device showing the disposition of the individual tubular probes at the distal tip of the delivery device.
FIGS. 6A, 6B and 6C are side elevational views of the preferred embodiment of the device illustrating the relationship between the RF microcoils and individual tubular components of the distal tip of each drug delivery catheter.
FIG. 7 is a flowchart of the MR imaging methods used to establish the position and orientation of the delivery device, and to track the spatial distribution kinetics of a material injected or infused from the delivery device into tissue.
FIG. 8 illustrates how the method of the invention is used to track the spatial distribution kinetics of different drug agents based on their signal intensity decay profiles following injection into a homogeneous cavity in the brain extracellular compartment
FIG. 9 illustrates how the method of the invention is used to track the spatial distribution kinetics of different drug agents based on their respective signal intensity decay profiles following injection into the heterogeneous extracellular space of the brain.
FIG. 10 illustrates how the method of the invention is used to track the spatial distribution of a drug agent that is injected into heterogeneous brain tissue comprised of nerve cells and nerve fibers.
FIG. 11 illustrates how the method of the invention is used to track the spatial distribution of a drug agent injected into the region of a brain tumor.
DETAILED DESCRIPTION OF THE INVENTION
One of the significant difficulties with delivery of materials such as drugs, hormones, or neurotransmitters to living tissue is assuring that the materials are delivered to the target receptor location in the intended amount. Many materials which are delivered to a patient, even though beneficial in the treatment of a specific condition, may be moderately or even strongly noxious or damaging to healthy tissue. It is therefore one object of conventional materials application treatment to maximize dosage to a desired location and to minimize dosage to locations which do not require the delivery of the material. Additionally, newer medical treatments may include procedures which remove unwanted deposits of materials with an expectation that the removal will be assisted by physical removal (by a withdrawal system) or natural bodily function removal (e.g., the circulatory system), or which may attempt to stimulate the body to produce natural chemicals (of which a patient may be deficient) at an increased rate (e.g., electrical stimulation to increase the production of dopamine). Because these procedures are usually highly invasive, it would be extremely desirable to have a real time indication of immediate, transient and persistent effectiveness of the procedure. Where undesired deposits or collections of materials are being dispersed, it would be desirable to visualize the actual movement of materials to assist in collecting them (e.g., through catheters) or tracking them to assure that they are not again depositing or collecting (as in intravenous or cerebrospinal fluid blockage), or moving in segments which are too large and could cause blockage in other parts of the body as they are carried about.
Unfortunately, with in vivo delivery of materials, particularly extremely small doses in small volumes delivered by small instrumentation into tissue regions protected by the blood-brain barrier, or the brain-cerebrospinal fluid barrier, or into visually inaccessible areas, it has not been possible to observe real time distribution of the material delivery, or the dispersion or distribution of the material at the injection or infusion site within the tissue. Where even small variations or miscalculations about the location of the target sight and the delivery device can significantly affect the delivery of material and the effectiveness of the delivered material, real time observation of the material delivery is even more critical than in topical or gross (e.g., massive systemic injection) delivery events. There has been no truly effective observation system for such delivery prior to the present invention.
The basic operation of the present invention therefor involves the initial MR imaging observation of a molecular environment of a patient (e.g., a particular area or region of a patient, such as tissue, particularly such tissue as that present in organs or systems of animal bodies and especially the human body, including, but not limited to the intracranial compartment and the various anatomic regions of the brain, including the cerebral ventricles, cisterns, epidural and subdural spaces, sinuses, and blood vessels, the spinal cord, including disks, nerves and associated vascular system, the heart and the coronary vascular circulation, liver and the hepatic vascular circulation, kidney and the renal vascular circulation, spleen and the splenic vascular system, gastrointestinal system, special senses, including the visual system, auditory system, and olfactory system endocrine system including the pituitary gland, thyroid gland, adrenal gland, testes, and ovaries, with observation of an MR image signal intensity at a given time and/or state (e.g., prior to material introduction or at some defined stage of material diffusion into the molecular environment. In an example of the method of the invention, the distribution of the material in the tissue is determined by releasing an amount of the material through a drug delivery device positioned in the tissue, allowing the material to diffuse in the tissue, and analyzing the resulting MR signal intensity. On a continual basis or at some subsequent time interval later (e.g., a pulsed interval, preselected interval, random interval, frequent or sporadic intervals), the MR image of the molecular state within the same general area is observed. Changes in the characteristics, properties or quality of the image, such as the image signal intensity within the area are presumptively (and in most cases definitively) the result of the introduction of material into the original molecular environment and alteration of the MR response for regions of the environment where delivered material concentration has changed. By repeating observation of the MR image signal intensity within an area at least once (e.g., first taking the initial observation at a material concentration state at a time T 1 , and at least one subsequent observation of MRI-observable changes such as in the signal intensity qualities at a time T 2 ), the change in MR image signal intensity qualities can be related to the change in material concentration between times T 1 and T 2 , whether that change is from a starting point of zero concentration or from an existing concentration level. The observations therefore relate to the actual delivery of material into the molecular environment in an observable, and to some lesser degree, quantifiable manner.
The change in the signal, e.g., the change in the amplitude of the MR signal in the visible image may be altered by:
a) a change in the apparent diffusion coefficient (ADC) of tissue water protons;
b) a change in tissue magnetic susceptibility (BO);
c) a change in T1 tissue relaxivity (T1);
d) a change in T2 tissue relativity (T2);
e) a change in tissue magnetization transfer coefficients (MTC);
f) a change in tissue chemical shift frequency;
g) a change in tissue temperature; or
h) a combination of any one or more of a)-g) alone or with other effects.
The MR signal is dephased by the random motion of diffusing water molecules, and the presence of the delivered material locally affects the degree to which the amplitude of the signal is altered by the dephasing. If the amount of active ingredient to be delivered is quite small, or the effect of that material on the alteration of the amplitude is minimal, the delivered material may be associated with a larger amount of a second material or another more MR signal responsive material, which are preferably selected on a basis of similarity in diffusion rates through like materials or at least comparable (mathematically relatable) diffusion rates. In this manner, using such a taggant material, the diffusion of the delivered material may be assumed to relate to the diffusion/delivery of the taggant material. Unlike other observational techniques, these taggant materials may be readily provided as non-toxic, inexpensive taggant materials since there is such a wide variety of materials which could be so used, and their only functional requirements would be diffusion rate and non-toxicity. Many dyes commonly used in medical procedures could be used for this purpose.
The availability of an MR-visible drug delivery device combined with MR-visible chemical or drug agents would make it possible to obtain near real-time information on drug delivery during interventional procedures in an intra-operative MR system, as well as for pre-operative and post-operative confirmation of the location of the drug delivery device. Medical and surgical applications would include vascular surgery and interventional radiology, cardiac surgery and cardiology, thoracic surgery and radiology, gastrointestinal surgery and radiology, obstetrics, gynecology, urology, orthopedics, neurosurgery and neurointerventional radiology, head & neck surgery and radiology, ENT surgery and radiology, and oncology. In addition to direct tissue injection, the method of the invention applies to drug delivery via intraluminal, intracavitary, laparoscopic, endoscopic, intravenous, intraarterial applications.
There is currently considerable interest in the therapeutic use of small ions as well as macromolecules in the treatment of various neurologic diseases. To be effective, such molecules must be able to reach target tissue receptors. Many molecules that are used in therapeutic drugs are large in size, for example, neuroleukin, a neuromodulator drug tested for treatment of amyotrophic lateral sclerosis is about 56 kDa, bethanechol chloride used in treatment of Alzheimer's Disease is about 196 kDa and nerve growth factor is about 13 kDa. While the importance of large molecular weight molecules in direct parenchymal drug therapy is growing, little is known about the time course and the spatial range of their actions, since dynamic visualization methods for studying macromolecular diffusion have not been available.
Diffusion of drug and/or water protons in a complex medium, such as a brain cell microenvironment, is influenced by numerous factors. Materials injected into the brain or spinal cord do not move unimpeded through the aggregations of neurons, glia, capillaries, and nerve fibers. The distribution of a drug volume in the brain cell microenvironment following injection directly into brain tissue is governed by a number of factors including the physicochemical characteristics of the drug, capillary uptake, metabolism, excretion, size of the extracellular space (the volume fraction), and geometry of the brain cell microenvironment (tortuosity). The degree to which each of these factors influences the distribution of a particular drug agent within the brain or spinal cord is an important determinant of the effectiveness of drug treatment of diseases of the central nervous system.
Despite the fact that the average spacing between brain cells may be no more than 20 nm, the mean free path of an ion at the typical ionic strength of the mammalian nervous system (about 0.15) is only about 0.01 nm. In ways similar to altering the local ADC of the water protons, presence and transport of a drug through a tissue will also alter the magnetic susceptibility, T1, T2, MTC, water proton diffusion anisotropy, chemical shift frequency, and temperature of the protons within each imaged voxel. This represents the distance traveled between collisions with other molecules. Almost all these collisions actually take place with water molecules since the concentration of water is 55 M. Thus ions intrinsic to the brain rarely encounter cell membranes and generally behave as though they were in a free medium. However, the diffusivity properties becomes much more complicated when the boundary has a complex geometry, or when macromolecular interactions involve exogenous solutions injected into tissues.
In complex media such as brain tissue, diffusion obeys Ficks Law, subject to two important modifications. First, the diffusion coefficient, D, is reduced by the square of the tortuosity factor to an apparent diffusion coefficient ADC*=D/tortuosity factor 2 because a diffusing material encounters membranous obstructions as it executes random movements between cells. Second, the source strength is divide by the volume fraction of the extracellular space so that a given quantity of released material becomes more concentrated than it would have been in a free medium.
In most media, tortuosity and volume fraction are essentially dimensionless factors which depend only on the geometrical constraints imposed by local structures. In brain tissue, however, a third factor, non-specific uptake, is present in the diffusion equation as a term, k', for loss of material across the cell membranes. In fact k' can be expressed as P(S)/volume fraction, where P is the membrane permeability and (S) is the volume average of the membrane surface area. Complex local boundary conditions imposed by cell membranes can thus be removed by averaging the local diffusion equations and boundary conditions over some characteristic volume of tissue a few micrometers in extent. Thus in the case where a substance is injected from a point source at a rate of q moles/sec in a free medium, the source term becomes q/tortuosity in a complex medium while the diffusion coefficient ADC is modified to be ADC/volume fraction 2 in the new equation, which is the apparent diffusion coefficient.
Knowledge of the properties of the brain extracellular microenvironment is thus essential to understanding the role of diffusion in delivering metabolic or therapeutic agents to brain or spinal cord cells. Diffusion has been determined employing radioactive or fluorescent tracers, in which the concentration profiles of the tracer are monitored over time, and its diffusivity is inferred from the data. Microscopic displacements can be seen with tracers on the scale of millimeters. Spatially resolved methods, such as infrared spectroscopy or Rayleigh scattering, have been used allowing resolution in the micrometer range. Such tracer techniques have been successfully applied in biological systems, such as the brain. However, because of the inherent invasiveness of using exogenous tracers, such techniques cannot be used in vivo with humans.
Techniques have also been developed for determining the diffusion characteristics of small molecules in local regions of the brain using radiotracers, microiontophoresis, or pressure microinjection combined with ion-selective microelectrodes. The applications of these methods to intracranial drug delivery have been described in the medical literature, for example, Lux et al., Exp. Brain Res., 17, 1973, pp. 190-205, Gardner-Medwin, Neurosci. Res. Progr. Bull., 1980, 18, pp. 208-226, Nicholson et al., J. Physiol., 1981, 321, pp. 225-257, Nicholson et al., Brain Res., 1979, 169, pp. 580-584. However, these techniques have several key limitations. First, these techniques provide a measurement at only a single point in the tissue so that spatial patterns of diffusion cannot be determined. Second, ion-selective microelectrodes can only be used with a few small ions. Third, since radiotracer techniques rely on postmortem counting of particles in fixed and sectioned tissues, they provide limited spatial resolution and no dynamic information.
Several previous studies have obtained estimates of the ADC of large fluorescent molecules from digitized images of fluorescent molecules as they diffused away from blood vessels. However, the complicated geometry of the source and inability to precisely characterize the emitted flux, substantially limit the clinical utility of the information. Similarly, new optical imaging methods, in which a uniform distribution of fluorescent tracer is first established in the sample and then a region is photobleached with a strong laser, has serious limitations because the laser beam can also damage the tissue area being imaged. Studies with optical fluorescence methods suggest that molecules as large as 70 kDa can pass through the brain extracellular microenvironment Below some limit between 10 and 40 kDa, molecular diffusion is not restricted any more than with much smaller molecules. Similar constraints have been found for diffusion in the brain intracellular microenvironment, whereby all molecules diffuse at least three times slower than in aqueous solution, suggesting a similar tortuosity in the intracellular environment.
An integrative optical imaging technique disclosed by Tao and Nicholson, Biophysical J., 1993; 65, pp. 2277-2290 yields an apparent diffusion coefficient from digitized images, and enables precise determination of the diffusion characteristics of fluorescently labeled compounds of high molecular weight. The generalized equations disclosed by Nicholson and Tao have two nondimensional factors that incorporate the structure of the tissue into the imaging solution. The first factor, the tortuosity, accounts for the hindrance to extracellular diffusion that arises from the obstructions presented by cell membranes. The second structural factor is the volume fraction, which is defined as the ratio of the volume of the brain extracellular microenvironment to the total volume of tissue averaged over some small reference domain. The method disclosed by Nicholson and Tao ("Hindered diffusion of high molecular weight compounds in brain extracellular microenvironment measured with integrative optical imaging." Biophysical J. 1993; 65:2277-2290) does not, however, yield a direct measurement of the molecular distribution in a three-dimensional sample, and furthermore requires use of large fluorescent markers which are not suitable for repeated injections in human patients.
An alternative approach to measuring diffusivity of therapeutic drug injections is to monitor the diffusion process itself, i.e. the random motions of an ensemble of particles. Einstein showed that the diffusion coefficient measured in nonequilibrium concentration cell experiments is the same quantity that appears in the variance of the conditional probability distribution, P(r/ro, t), the probability of finding a molecule at a position r at a time t, which was initially at a position ro. For free diffusion, this conditional probability distribution obeys the same diffusion relation. Thus, MR imaging parameters which reflect the differences in relative water proton-diffusion path lengths may serve to enable imaging differentiation between tissue water protons and protons in macromolecular solutions that are injected into brain tissues.
Molecular water-proton diffusion is caused by thermally induced random Brownian motion. As the protons continually collide with their microenvironments, their average random traveled pathlength <L>, along one direction (e.g. along the magnet-bore direction) is described according to Einstein as: <L2>=2 TD where over an observation time of T (seconds) the displacement is expressed by a "diffusion coefficient, D" in mm 2 /s or cm 2 /s. The diffusion process is continuous, so that the average displacement of any population of water protons increases with MR imaging time. However, the diffusion behavior of protons can be hindered by impermeable or semi-permeable barriers, such as cell membranes, and macromolecules, which may themselves contain populations of diffusing protons. For tissue water protons diffusing within a tissue matrix, the observed diffusion rate and direction will reflect the molecular and macromolecular barriers or hindrances that the diffusing protons encounter during their translational processes. One example of the application of this concept in human neurobiology is that myelinated nerve fibers in the brain and spinal cord preferentially dispose the diffusion of water protons along, rather than across, myelin tracts thereby giving rise to diffusional anisotropy MR imaging properties (Moseley et al., Mag. Res. Med., 19, 1991, pp. 321-326, Moseley et al., Topics Mag. Res. Med., 3, 1991, pp. 50-68).
Although noted for its effects on high-resolution, high-field MR spectra more than 25 years ago, molecular (water proton) diffusion has just recently been shown to have an important impact in clinical MR neuroimaging applications. While T1 and T2 relaxation times reflect frequency-dependent rotational and proton exchange processes, diffusion is caused solely by molecular or proton displacements or translations. Molecular size, shape, microenvironment, and temperature all influence the diffusion rate of molecules. Generally, larger molecules will translate (diffuse) more slowly than smaller molecules, such as water protons, and the differences in diffusion rates between different populations of molecules can be distinguished by signal intensity differences on diffusion-weighted MR images, particularly MR images which employ large diffusion gradients (b values). Thus, the measurable diffusion of smaller versus large molecules with MR imaging can be used as an in vivo tracer to probe the structural orientation of the tissues into which the drug agent has been injected. Advances in diffusion-weighted MR imaging have been made possible by major technical improvements in MR scanner hardware and software. High-speed MR echo-planar imaging now enables subsecond diffusion-sensitive imaging of water proton behavior in brain and spinal cord.
Thus, MR-visible molecules may exist in a variety of environments in brain tissue, which modify the way in which the molecules can move. First, the space in which the molecules can move may be small (e.g., intracellular) or large (e.g., an enlarged extracellular space). Second, the amount of dissolved compounds and proteins may alter the viscosity of the substance injected into the tissue. The random movement of the molecules is characterized by its diffusion coefficient ADC as the mean square distance moved for unrestricted isotropic (i.e. same in all directions) diffusion (for example a large sample of pure water). ADC is high in pure water, and lower by about a factor of 10 in tissue. As tissue becomes destroyed by disease processes, ADC is expected to rise toward its free water value. Diffusion-weighted imaging, in which field gradients are applied to attenuate the signal from rapidly diffusing water, shows increased image intensity in areas of low ADC. Similarly, the presence of a drug in tissue, or its transport through tissue extracellular, intercellular or intracellular microenvironments, will also alter the magnetic susceptibility, T1, T2, MTC, water proton diffusion anisotropy, chemical shift frequency, and temperature of protons within each imaged voxel.
The medical treatment and the medical device used in the practice of the present invention, even when a delivery device, may also be a diagnostic device rather than only a treatment device. For example, there are numerous diseases which alter the thickness of specific layers or coverings within the body, such as the myelin around nerves. The present invention provides a diagnostic tool to the degree that alterations in the thickness or existence of coatings such as myelin will alter the transport of chemical from one part of the body to another. Where, as in certain myelin deficiency diseases such as Multiple Sclerosis, the effect on the myelin is progressive and not uniform, the administration of chemicals into an area under MR imaging guidance according to the present invention can enable viewing of the variations in the rate of migration or transport of these observable chemicals to different areas of the myelinated nerve. The degree of advance of the disease can thus be observed, and it is possible to diagnose or even quantify the stage of the disease more acutely and comparatively within a given patient According to that method, a chemical material would be introduced into the patient, and the relative movement of that chemical through supposedly similar structures in the area could be observed. Significant differences in penetration rates and/or concentrations of these chemicals through similar tissue material (e.g., the myelin) would be indicative of different properties (e.g., thickness, hydrophilicity, porosity, etc.) which would be symptomatic of a disease. The observation would therefore provide data that could support or prove a clinical diagnosis of a disease which is known to affect the specific properties observed.
FIGS. 1 and 2 illustrate an MR-compatible drug delivery device made in accordance with the most preferred embodiment of the present invention. A variable-length concentric MR-visible multi-lumen catheter 4 is formed by extruding a tubular assembly with both porous 4b and non-porous 4a tubular components, The non-porous tubular component 4a is made of MR-visible elastomeric hydrogel, various polymeric compositions including polyvinylchloride, polyacrylonitrile, polyvinylidene fluoride, polystyrene, polyurethane, and polyamides, or other similar low friction material intended to minimize abrasive damage to the brain during insertion. One or more of the tubing conduits 2, 2a, 2b in the multi-lumen catheter are connected to a pump 3, 3a, 3b or other temporary reservoir 1, 1a, 1b, which circulates a therapeutic drug solution or MR-sensitive contrast agent through a dialysis fiber into a target tissue or pathological lesion. The distal terminus of each porous tubular component 4b has a dialysis probe 17 with a variable molecular weight cut-off membrane 18 which permits unimpeded movement of cerebrospinal fluid, small ions, and small molecular weight drugs, but is substantially impermeable to blockage by cellular material, said semipermeable membrane having a molecular weight exclusion of approximately 100-200 kD. The dialysis membranes can be made of regenerated cellulose hollow fiber tubing, as well as various polymeric compositions including polyvinylchloride, polyacrylonitrile, polyvinylidene fluoride, polystyrene, polyurethane, polyamides, cellulose acetates and nitrates, polymethylmethacrylate, polysulfones, polyacrylates, and derivatives, copolymers and mixtures thereof.
The inlet tubing of the dialysis probe is connected to a microinjection pump 3 or reservoir 1 providing a flow of 0.1-10 μl/minute of drug solution or sterile Ringer's solution perfusing the inside of the probe. The outlet tubing 2a is connected to a section of plastic tubing leading to a collection vial 3a. Regenerated cellulose hollow fiber dialysis tubing is cemented into the distal end of the plastic tubing with clear epoxy or other MR-compatible bonding material. The dialysis fiber (Spectra/Or; Spectrum Medical) or other similar commercially available semi-permeable membrane has a nominal molecular weight cut-off of 100-200 kD, an i.d. (interior diameter) of 5-50 μm, and a membrane length of 1-10 mm.
With further reference to FIGS. 1-3 of the drawings, the outlet tubing 2a is incorporated into the probe into the dialysis chamber 1 via a small perforation in the inlet tubing. The entire upper portion of the assembly, including the junction between the inlet tubing and plastic cannula, is sealed with epoxy. The outer tubing consists of 5-10 cm length of flexible fused silica tubing (Polymicro Technologies). These probes are inexpensive and easy to construct, and the small o.d. minimizes the tissue damage. The concentric design makes it simple to implant the probe into different intracranial locations.
With reference to FIG. 4, active MR visualization of drug delivery is achieved by means of one or more RF microcoils 9, 9a, 10, 10a positioned along the longitudinal axis of the device 4. Particularly preferred is an RF coil consisting of a circular loop of gold or other conductive material 9 positioned around the widest part of the drug delivery device, which would project the field-of vision (FOV) furthermost into the tissue. Depending on orientation of the coil with the magnetic B0, single microcoils may be used separately or may be constructed in an array that may be used together to optimally image the surrounding tissue structure and contrast. In order to reduce the thickness of the RF microcoil, the coil material is sputter-coated onto the surface of the drug delivery device. Preferred also for very small (nanoliter or microliter) injections is a solenoid volume RF microcoil 9a, which by design is sensitive only to the volume inside the coil, said imaging volume being directly related to the diameter of the RF coil. Another preferred MR imaging method which can be used to practice the invention is a combination of RF microcoil and surface coil positioned on the surface of the patient's head. Also preferred is telescoping coil 10 inside of the catheter, expanding it when one wants to image and then withdraw the coil and move on. One may see several cm with this idea. Another preferred method of MR imaging involves the use of an oblong surface loop of wire at the end of a slanted drug delivery device or along the shank of the device, thereby yielding a long FOV. In each of these preferred embodiments of the invention, the transmitting coil would be the head or body volume RF coil inside of the MR imager. The RF surface coil is used only for detection purposes. In another preferred embodiment, a preamplifier 10b positioned near the distal end of the delivery device 4 serves to amplify signals from the RF microcoils 9, 91, 10, 10a.
With further reference to FIGS. 3 and 4, the medical device used in the preferred practice of the present invention for delivery of materials may vary widely with respect to its structure, being highly dependent upon the particular procedural use to which it is being intended. However, there are many features which can be common to all of the devices or which should at least be considered in the various constructions. The simplest device could be a single delivery tube (catheter) which has MR responsive material in or on the composition of the tubing 19, preferably near the distal end or outlet of the delivery tube for assisting in detection by the MR imaging system. The next level of simplified construction would be the presence of MR coils or microcoils 9, 9a, 10, 10a at or near the distal end of the catheter. This again, as elsewhere described, improves the visibility of the viewable signal observable by the MRI system. More than one coil or microcoil may be present, as the distribution of microcoils along a length of the catheter helps define the region within which local signals are detected at efficient intensities. That is, each coil acts as a detector of local MR intensity, and each coil supports a volume around the coil which is observable by MRI systems. The coils may add or integrate their detectable volumes, defining a combined volume which can be efficiently observed by the MR system. As different medical procedures are performed in different environments, with different shapes and different variations in densities, the coils may be located, sized, angled, or otherwise designed to provide specific MR signals and/or responses tailored to the anticipated needs of a particular procedure. In general, the invention is best practiced by employing an array of RF microcoils, such that an image is obtained for any orientation of the drug delivery device.
The device may also include numerous catheter elements and/or ports and/or supplemental or independent functional elements. For example, as illustrated in FIG. 3, at least two ports 21, 22 may be needed, one to carry in on chemical material and another to deliver a second distinct chemical material which is or may become desirable during a medical procedure. For example, in addition to a primary treatment chemistry being delivered, saline solutions or specifically tailored solutions to dilute potential oversized deliveries could be desirable. Some treatments may require sequences of drug delivery or delivery of various drugs which may not be storage stable prior to delivery to a patient. Separate ports 23, 24 would be desirable in those events. Additionally, ports may be used to evacuate undesirable materials which are directly or indirectly introduced by the medical procedure. The withdrawal port 25 may comprise a tube with a port which can be attached to negative pressure with respect to the an opening in such a withdrawal port thus being able to reduce liquid or small particle solids volumes within the area of the procedure. Where the liquid volume or solids are MR viewable, the MR viewable device may be directed towards specific locations or areas and the ports targeted towards those specific areas. In addition, the various ports may be marked or designed to provide distinct signals when viewed by MR systems so that they may be distinguished during performance of the procedures. For example, MR insensitive materials may be used to line a port 26 or materials with different distributions or intensities of MR response may be used in the various ports to differentiate the elements while being observed during performance of procedures. For example, where a withdrawal tube 27 has openings through which materials may be withdrawn, the orientation of that opening within the device becomes important. By lining the edges of the opening with material having unique MR responsiveness within the device 28, the position and orientation of the opening can be readily determined. Particularly preferred is a 2,000-5,000 angstrom thick coating of MR-visible material along the distal shaft of the device.
Where multiple catheters or ports or functional elements are combined into a single device, the configuration of the different components should be tailored for a particular procedure. The different components may be associated by various orientations. As illustrated in FIG. 3B, the most preferred is generally a central tube or tubes with other tubes forming a circular distribution around the central tube or tubes. An MR-visible guidewire may be inserted within the device 4 to assist in positioning the device at a target anatomical location. Particularly preferred is a guidewire or other structural support made of Nitinol™ or other MR-compatible shape memory metal. This is the simplest geometry and provides for smallest diameter sizing of the device. As illustrated in FIG. 5A, other configurations such as parallel alignment of the elements in a strip-like orientation, stacking of elements in rows and columns, or mixtures of these and other configurations may also be useful. Other elements which may be included within the device, in addition to or separate from the use of delivery and/or withdrawal tubes 29, include thermal elements 30 (for providing heat), radiation carrying elements 31 (e.g., ultraviolet radiation, visible radiation, infrared radiation, and even hard radiation carrying elements, such as optical fibers or other internal reflection radiation carrying systems), detection elements 32 (e.g., pH indicators, electronic activity indicators, pressure detectors, ion detectors, thermal detectors, etc.), and any other sensing or detection element which would be useful during medical procedures. These individual elements are each extendable to permit optimal positioning within the tissue would be configured as desired or needed for the particular procedure intended for the device. Procedurally inert elements such as structural supports, reinforcing elements or coatings, back-up elements, and the like, may also be present within the device. Particularly preferred as structural supports or reinforcing elements are circumferential bands of Nitinol or other MR-compatible shape memory metals 35 which, when activated, can facilitate accurate directed placement of the functional tip of the device.
One type of configuration which is presently considered as the preferred embodiment of the invention is the use of a core of element(s) surrounded by a sheath or distribution of additional elements. For example, with further reference to FIGS. 3A and 3B, a central core element my comprise a single tube for delivery of a material, a pair of tubes for delivery of two chemicals, a delivery and withdrawal tube, or a procedurally inert structural support element 11. Around the central core element may be disposed multiple additional elements 21-27, usually seeking as near to a circular distribution about the central core as geometries allow. The attempt at the circular distribution is primarily for purposes of optimizing a small size for the diameter of the article, and is not necessarily a functional aspect to the performance of the device. With respect to FIG. 5, the MR responsive materials, including MR microcoils, may be located within the central core 33, around the central core 34 (beneath any next layering of elements), or over the elements surrounding the central core 34a. Where one or more of the elements receive, transmit or are powered by electrical signals, it is desirable that these elements be electrically separated by either or both of physical separation or additional insulation to prevent mixing or cross-transmission of signals between the distinct elements. Carrying and withdrawing tubes (as well as other elements) may also secondary functions. For example, a carrying tube may be conductive (by being naturally conductive or by having a conductive coating in or outside of the tube) and the electrical connection may be associated with an electronic element or component at the distal end of the device. The tube may thereby act as a carrying tube and electrical connection to the electronic component or element. Structural or adhesive support materials between different elements may also provide such functions. The system may have the material delivery device comprise a catheter assembly of from 2 to 10 mass transporting elements.
The various individual elements within the device must be structurally associated, especially away from the distal end, and during insertion, may need structural association at the distal end 11. The structural support or structural integrity may be provided by some physical means of attaching the various elements. This may be done by adhesive materials between the individual elements (which adhesive should be MR compatible), fusion of the various elements, or by coextrusion of the tubes into a single unit (or single component of a multiple element device). The adhesive may be an organic or inorganic adhesive. The distal end of the device may have the ends of the elements temporarily or controllably bonded during insertion. This may be beneficial because it may be desirable to have the individual elements fan out or separate during a medical procedure, for example, as in the case of a target tissue or area of pathology which is anatomically extensive. The adhesive could be water soluble (which would dissolve in a timely manner after insertion), solvent soluble (with solvent delivered into the distal end during a preliminary procedure, or radiation disruptable (e.g., a positive-acting resist adhesive composition which is sensitive to UV, visible or IR radiation which may be delivered through a radiation carrying port). Many other variations and combinations of these considerations and constructions may be used within the practice of the present invention.
With reference to FIG. 6a, in another embodiment the dialysis probe is replaced by an MR-visible microcatheter 38, which is a single extrusion catheter made from one of several possible sizes of a polyethylene terephthalate proximal shaft, e.g. 30 ga. The 1-2† mm distal segment of the microcatheter drug delivery device is made of elastomeric hydrogel or similar soft material which minimizes tissue damage during insertion. A plurality of semipermeable membranes 38b are placed circumferentially at regular intervals along the distal segment of the microcatheter, thus enabling wide dispersion of an injected agent, semipermeable membrane consisting of a 0.18-0.22 mμ millipore filter. The companion microguidewire in this example is made of nitinol or similar memory metal which enables directed placement of the tip of the catheter. The microguidewire 37 is threaded into a clear hub luek-lock cap 39 made of poly-methel-pentene or similar compatible plastic. Both the catheter and guidewire have a linearly arranged array of radiopaque and MR-visible markers 40 disposed at the distal end to provide easily identifiable reference points for trackability and localization under MR imaging and X-ray fluoroscopy guidance. The microcatheter can also be made from any of the well-known soft, biocompatible plastics used in the catheter art such as Percuflex, a trademarked plastic manufactured by Boston Scientific Corporation of Watertown, Mass. With further reference to FIG. 6a of the drawings, when the delivery device is positioned intracranially, the distal markers will be identifiable in an MR image and by X-rays. In another preferred embodiment, two or more RF microcoils are placed along the distal shaft of the microcatheter.
With further reference to FIG. 6 of the drawings, the delivery device can be employed to deliver pharmacologic therapies in order to reduce morbidity and mortality associated with cerebral ischemia, intracranial vasospasm, subarachnoid hemorrhage, and brain tumors. In the method of the invention the distal tip of the multi-lumen catheter assembly is typically positioned a few millimeters above the intracranial target structure using MR imaging. In one preferred embodiment of the invention illustrated in FIGS. 6B and 6C, surface modifications of the material components of the dialysis probe 18 enable timed-release kinetics of MR-visible biologic response modifiers, including peptide macromolecules. In another preferred embodiment of the invention, a pump or other infusion or injection device circulates a solution containing a therapeutic drug or an MR-visible contrast agent through the walls of the dialysis fiber into the brain at rates between 0.01 ul/min to 10 ul/min. In another preferred embodiment of the invention, pressure ejection techniques well described in the medical literature are used to deliver a predetermined amount of a therapeutic drug agent or MR-visible contrast through one or more of the tubular components of the multi-lumen device. In one specific preferred embodiment of the invention, the catheter is backfilled with the drug or contrast agent, which is functionally connected to a Picospritzer™ (General Valve Corp, Fairfield, N.J.) or a similar instrument that is able to deliver pulses of nitrogen or compressed air with a duration ranging from a few milliseconds to several seconds at a pressure of 10-50 psi. Using such a pressure ejection mode of drug delivery, the concentration of the released substance in the vicinity of the tip is accurately defined by the concentration of the material in the delivery device. A binary solution can also be released, in that two therapeutic or diagnostic compounds can be delivered at the same time by pressure ejection of two materials from two or more separate microcatheters.
In another embodiment of the invention, the MR-visible solution contains sterically stabilized liposomes, with lipophilic or hydrophilic chelators, such as polyaminocarboxylic acids and their salts, such as DTPA on phosphatidyl ethanolamine or steric acid embedded within the external bilayer, or double-label liposomes that chelate a T2-sensitive metal ion within the internal aqueous space and another T1-sensitive metal ion on the outside membrane surface, or liposomes which contain 100-1000 nm air-bubbles, such as argon, carbon dioxide, or air, as a contrast agent In another preferred embodiment, RF microcoils 41a-f are positioned at the distal ends of individual delivery tubes, said microcoils acting as local MR detectors.
With further reference to FIGS. 1 and 2, in a method of the invention, the implantable MR-visible multilumen catheter includes in another tubing conduit a hydrocephalus pressure valve 1C and self-sealing port 1D preferably made of Nitinol™ or other similar MR-compatible material for regulating the flow of cerebrospinal fluid through the catheter after placement of the catheter tip into cerebral ventricle or other intracranial fluid compartment under MR imaging guidance.
With further reference to FIGS. 1 and 2, in the method of the invention, the implantable MR-visible multilumen catheter also includes in another tubing conduit a metabolic biopsy microcatheter which is used to collect and measure the number of small molecules present in the extracellular fluid, including energy-related metabolites, such as lactate, pyruvate, glucose, adenosine, and inosine, and excitatory amino acids, such as glutamate and aspartate, in a separate reservoir 3b.
With reference to FIG. 7 to FIG. 11 of the drawings, in the method of the invention, MR imaging is used to differentiate normal brain tissues from various pathologic conditions, including solid brain tumor, abscess cavity, edema, necrotic infarcts, reversibly ischemic infarcts, demyelination, and hemorrhage, based on the characteristic ADC of these tissue pathologies already well established in the medical literature. In order to determine the delivery and distribution kinetics of intracerebrovascular, intrathecal, and intra-parenchymal injections or infusions of drug or contrast agents within the brain for purposes of creating a means of acquiring a "metabolic" biopsy, a sequence of MR images are collected over a period of time t, which is preferably <100 min and >10 sec. The MR intensity distribution and spatial variation of the calculated ADC of the tissue volume undergoing MR imaging prior to drug delivery is compared with the ADC in the same region following drug delivery in order to determine the efficacy of drug delivery to the targeted intracranial loci.
Methods to obtain absolute measurements of ADC using MR imaging have been described in the medical literature, for example, Moseley et al., Mag. Res. Med., 19, 1991, pp. 321-326, and Moseley et al., Topics Mag. Res. Med., 3, 1991, pp. 50-68). It is well established that if there is restriction to diffusion (e.g. from cell walls), then the measured ADC will decrease with increasing diffusion time. Thus, an express objective of the present invention is to evaluate the efficacy of MR image-guided drug delivery by measuring restricted diffusion with localized MR pulse sequences. In the method of the present invention, modeling of restricted diffusion is used to estimate the size of the diffusion spaces and the permeability of the barriers to drug agents injected into the brain microenvironment. A conventional imaging sequence is repeated with field gradients of increasing strength or duration. The signal decays away exponentially as e-bD, where b depends on the strength, duration and timing of the diffusion-sensitizing gradients. However, the diffusion gradients make the sequence extremely sensitive to motion. Thus, in a preferred embodiment of the invention, a navigator echo technique, or its variants, are used to suppress the contaminating effects of patient motion on the ADC measured with MR imaging. In another preferred embodiment, high speed echoplanar imaging is used without movement artifact. In a further preferred embodiment of the present invention, localized measurements of the ADC, ΔB0, T1, T2, MTC, chemical shift frequency, and temperature are acquired from images produced from single-shot or multi-shot stimulated echo (STEAM), gradient echo (GRE or FLASH), or fast spin-echo (FSE) MRI sequences.
In one preferred embodiment of the imaging method of the invention, a 1.5 tesla, 80-cm-bore MR imager with actively shielded gradients of at least 20 mT/m is used to acquire axial diffusion-weighted echoplanar images through a volume of brain tissue one slice at a time, with separate application of diffusion gradients in three orthogonal directions. Trapezoidal diffusion gradients, equal in magnitude and duration, are applied in the vertical (anterior-posterior) direction, and phase-encoding gradients are applied in the horizontal (left-right) direction. A 5-cm field-of-view and 200-kHz continuous readout sampling is preferred, which requires a plateau readout gradient of 12 mT/m. Also preferred are readout gradient trapezoids with 320-microsecond ramps and 640-microsecond plateaus, resulting in 1.28-millisecond readout lobes and 82-millisecond total readout time. The spin echo is placed coincident with the zero-phase-encoded gradient echo. To attain the preferred diffusion gradient of b=600 s/mm2, a spin-echo time of 90 milliseconds was used, and the center of k-space is placed symmetrically. Diffusion-weighted images are preferably acquired as 16 contiguous 1.5 mm slices at 1 slice per second in an interleaved order to minimize magnetization transfer and slice cross-talk effects. At least four diffusion strength, preferably b=10, 207, 414, and 621 s/mm2, should be applied separately in each primary orthogonal direction. Reference scans are acquired without phase-encoding gradients to allow correction of echo position and phase before Fourier transformation reconstruction, to minimize image ghosts. Thus, in the preferred method of the invention, a total of 384 diffusion-weighted echo-planar scans are acquired in approximately 6.4 minutes. The resulting 128×128 images are reconstructed by two-dimensional Fourier transformation. Nominal image resolution is 1.6 mm×2.1 mm×5 mm, giving a 17-uL nominal voxel.
With reference to FIGS. 8-11 of the drawings, in the most preferred embodiment of the MR imaging method of the invention, a therapeutic drug agent is injected from an MR visible drug delivery device into the intraparenchymal extracellular space of the brain. The solution containing the macromolecular drug agent may either form a cavity or infiltrate the extracellular space depending on a number of factors. In either case, subsequent diffusion is governed by the volume fraction (extracellular or pore fraction), the tortuosity of the brain tissue (apparent increase in path length of the diffusing particle), and the diffusion coefficient of the substance itself. A finite and specified concentration of the substance with a finite and specified volume is deposited in the tissue in a period that is effectively instantaneous (i.e. <<time-scale of subsequent diffusion measurements). The injected volume of substance can exhibit at least two distinct behaviors disclosed by MR imaging in the method of the present invention.
In the first example, summarized in FIG. 8, the injected volume can form a fluid-filled cavity in the tissue, within which the volume fraction and tortuosity take the value of unity which corresponds to a free aqueous solution. Outside this region, the brain tissue has a volume fraction and tortuosity. In this example, diffusion as a function of distance from the injected substance can be represented as a series of curves denoting the concentration as a function of distance from the center of the cavity at successive time intervals. Different drug agents will diffuse at different rates thereby yielding characteristic individual signal intensity delay curves on MR imaging. At the interface between the fluid-filled cavity and surrounding brain tissue two continuity conditions involving flux and concentration apply. Since the amount of material leaving the first region, per unit area of the interface, must be equal to the amount arriving at the second, the phase averages of the fluxes in the two regions must be equal.
In the second example, summarized in FIG. 9, the injected material does not form a cavity but instead infiltrates the extracellular space. The diffusion of each agent is related to its molecular weight, molecular radius, and the tissue matrix structure into which the material is injected. Throughout the whole brain tissue, the diffusion behavior is governed by the volume fraction and tortuosity and no discontinuity exists.
In the third example of the MR imaging method of the invention summarized in FIG. 10, MR visualization of a drug agent injected into a region of nerve fibers in the brain or spinal cord is performed with diffusion-weighted anisotropic MR imaging. In the preferred method of anisotropic imaging, a 3×3 matrix (tensor) is used, and the signal loss is measured for at least six directions of diffusion gradient. The matrix can be transformed to one that is independent of the directions along which the gradients were applied, and therefore of the orientation of the patient in the magnet. In the preferred method, two measurements are of particular interest. First, the trace of the tensor (i.e. the sum of the diagonal elements) is relatively uniform throughout normal brain, despite its anisotropic structure. It can be thought of as the diffusion coefficient averaged over all directions. Second, an anisotropy index, such as the ratio of the diffusion coefficient in the most freely diffusible direction to that in the least freely diffusible, is highly sensitive to the directionality of the tissue structure. To measure high values in a directional structure the voxel size should be small enough so that there is no averaging of directions within the voxel. Loss of tissue structure is likely to decrease the anisotropy, as the tissue becomes more like a homogenous suspension. Clinical observations of changes in diffusion behavior have been made in multiple sclerosis, in stroke, where the reduction in diffusion precedes the increase in T2, and in experimental epilepsy.
In the fourth example of the MR imaging method of the invention (FIG. 11) macromolecular transport of drugs in tumor tissue is hindered to a lesser extent than in normal tissue, resulting in an altered ADC which enables the visualization of injected drug in neoplastic versus normal tissues.
A catheter system for delivering fluid to a selected site within a tissue comprises a pump for delivering the fluid and a catheter coupled to the pump. The catheter comprises a first tubular portion that has a generally cylindrical lumen of a first internal diameter and is composed of a relatively impermeable material. A second tubular portion that has an open end is disposed within the lumen and a closed distal end is disposed without the lumen. The second tubular portion is composed of a flexible, porous material having a preselected microporosity that is operable to permit fluid to flow from the catheter into the tissue. The second tubular portion is selectively moveable with respect to the first tubular portion. Alternatively, a catheter for delivering fluid to a selected site within a tissue comprises a first tubular portion that has a generally cylindrical lumen of a first internal diameter and is composed of a relatively impermeable material. A second tubular portion that has an open end is disposed within the lumen and a closed distal end is disposed without the lumen. The second tubular portion is composed of a flexible, porous material that has a semi-permeable membrane with pre-selected molecular weight exclusion that is operable to permit fluid to flow from the catheter into the organism. The second tubular portion is selectively moveable with respect to the first tubular portion. | The invention is an apparatus and method for targeted drug delivery into a living patient using magnetic resonance (MR) imaging. The apparatus and method are useful in delivery to all types of living tissue and uses MR Imaging to track the location of drug delivery and estimating the rate of drug delivery. An MR-visible drug delivery device positioned at an target site (e.g., intracranial delivery) delivers a diagnostic or therapeutic drug solution into the tissue (e.g., the brain). The spatial distribution kinetics of the injected or infused drug agent are monitored quantitatively and non-invasively using water proton directional diffusion MR imaging to establish the efficacy of drug delivery at a targeted location. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to a process for liquefaction and saccharification of biomasses containing polysaccharides, having a high dry matter content and preferably possessing fibres and particles with large average sizes. Furthermore the present invention relates to the further utilisation of such processed biomasses, e.g. for subsequent fermentation into bio-ethanol, specialty carbohydrates for food and feed as well as carbon feedstock for processing into plastics and chemicals.
BACKGROUND OF THE INVENTION
[0002] Numerous industrial and agricultural processes e.g. municipality operations, food and feed processing and forestry generate biomasses, waste and by-products containing polymeric sugars e.g. in the form of starch, cellulose and hemicellulose. Agribusiness and chemical industries as well as public organisations have considerable interest in developing processes for converting such biomasses into materials of a higher value. Thus, by way of example such biomasses could potentially be converted into bio-ethanol, biogas or chemicals using microorganisms and/or hydrolytic enzymes. However, the majority of processes known today have not yet reached large-scale commercial practice due to their high production cost and high energy demand and thus inherent uncertain economic feasibility.
[0003] Besides being important as food and feed, carbohydrates from biomass can be used as feedstock for a number of industrial processes. In the form of polymers a well-known product is paper where cellulose is the main component. However, when processed into oligomers and monomers carbohydrates are an important feedstock for a number of industrial processes. As will be described in detail they are necessary for a number of microbial processes, but in addition they can be used as feedstock for e.g. enzymatic processing into specialty carbohydrates for food and feed e.g. trehalose. Also carbohydrate oligomers and monomers may substitute petrochemicals for processing into plastics and organic chemicals. Furthermore, carbohydrates may be used as hydrogen carriers in catalytic hydrogenation.
[0004] It is therefore evident that if a low-cost and abundant resource of processed carbohydrates can be made available for industrial processing it may have a substantial economic potential.
[0005] Starch is the most widespread storage carbohydrate in plants and occurs in the form of granules, which differ markedly in size and physical characteristics from species to species. Starch granules are generally quite resistant to penetration by both water and hydrolytic enzymes due to the formation of hydrogen bonds within the same molecule and with other neighbouring molecules. However, these inter- and intra-hydrogen bonds can become weak as the temperature of the suspension is raised. When an aqueous suspension of starch is heated, the hydrogen bonds weaken, water is absorbed, and the starch granules swell. This process is commonly called gelatinization because the solution formed has a gelatinous, highly viscous consistency. Chemically, starch is a natural polymer of glucose, which is generally insoluble but dispersible in water at room temperature and made up of a repeating unit similar to that of cellulose and linked together by α-1,4 and α-1,6 glucosidic bonds, as opposed to the β-1,4 glucosidic bonds for cellulose. The units form either a linear chain component, called amylose, or a branched chain component, called amylopectin. Most plant seeds, grains and tubers contain about 20-25% amylose. But some, like e.g. pea starch have 60% amylose and certain species of corn have 80% amylose. Waxy varieties of grains, such as rice, are low in amylose.
[0006] Apart from starch the three major constituents in plant biomass are cellulose, hemicellulose and lignin, which are commonly referred to by the generic term lignocellulose. Polysaccharide containing biomasses as a generic term include both starch and lignocellulosic biomasses.
[0007] Cellulose, hemicellulose and lignin are present in varying amounts in different plants and in the different parts of the plant and they are intimately associated to form the structural framework of the plant.
[0008] Cellulose is a homopolysaccharide composed entirely of D -glucose linked together by β-1,4-glucosidic bonds and with a degree of polymerisation up to 10,000. The linear structure of cellulose enables the formation of both intra- and intermolecular hydrogen bonds, which results in the aggregation of cellulose chains into micro fibrils. Regions within the micro fibrils with high order are termed crystalline and less ordered regions are termed amorphous. The micro fibrils assemble into fibrils, which then form the cellulose fibres. The partly crystalline structure of cellulose along with the microfibrillar arrangement, gives cellulose high tensile strength, it makes cellulose insoluble in most solvents, and it is partly responsible for the resistance of cellulose against microbial degradation, i.e. enzymatic hydrolysis.
[0009] Hemicellulose is a complex heterogeneous polysaccharide composed of a number of monomer residues: D -glucose, D -galactose, D -mannose, D -xylose, L-arabinose, D -glucuronic acid and 4-O-methyl- D -glucuronic acid. Hemicellulose has a degree of polymerisation below 200, has side chains and may be acetylated. In softwood like fir, pine and spruce, galactoglucomannan and arabino-4-O-methyl-glucuronoxylan are the major hemicellulose fractions. In hardwood like birch, poplar, aspen or oak, 4-O-acetyl-4-methyl-glucuronoxylan and glucomannan are the main constituents of hemicellulose. Grasses like rice, wheat, oat and switch grass have hemicellulose composed of mainly glucuronoarabinoxylan.
[0010] Lignin is a complex network formed by polymerisation of phenyl propane units and it constitutes the most abundant non-polysaccharide fraction in lignocellulose. The three monomers in lignin are p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol, and they are most frequently joined through arylglyceryl-β-aryl ether bonds. Lignin is linked to hemicellulose and embeds the carbohydrates thereby offering protection against microbial and chemical degradation.
[0011] As stated above the processed biomasses could potentially be converted into bio-ethanol or chemicals using microorganisms and/or hydrolytic enzymes, or the carbohydrates from the processed biomasses could be used as feedstock for a number of industrial processes, e.g. enzymatic processing into specialty carbohydrates for food and feed or as substitutes for petrochemicals in the production of plastics and organic chemicals. In addition the processing of carbohydrates in biomass according to the present invention can be combined with separation and fractionation of the non-carbohydrate components. A particularly preferred use of a process according to the present invention is an integrated part of a process for bio-ethanol production.
[0012] Bio-ethanol production from polysaccharide containing biomasses can be divided into three steps: 1) pre-treatment, 2) hydrolysis of the polysaccharides into fermentable carbohydrates 3) and fermentation of the carbohydrates.
[0013] Pre-treatment is required if subsequent hydrolysis (e.g. enzymatic hydrolysis) of the polysaccharides requires the break down of an otherwise protecting structure (e.g. lignin) of the plant materials. Several pre-treatment techniques are known. For cereals and grains, this pre-treatment may be in the form of a simple dry milling in order to render the surfaces accessible, but for lignocellulosic biomasses thermal and/or chemical processes are needed as well. A polysaccharide containing biomass consisting of e.g. refined starch does not require said pre-treatment methods prior to enzymatic processing. Pre-treatment-processes may be based on acidic hydrolysis, steam explosion, oxidation, extraction with alkali or ethanol etc. A common feature of the pre-treatment techniques is that combined with the action of possible added reactants they take advantage of the softening and loosening of plant materials that occurs at temperatures above 100° C.
[0014] Following the pre-treatment, the next step in utilisation of polysaccharide containing biomasses for production of bio-ethanol or other biochemicals is hydrolysis of the liberated starch, cellulose and hemicellulose into fermentable sugars. If done enzymatically this requires a large number of different enzymes with different modes of action. The enzymes can be added externally or microorganisms growing on the biomass may provide them.
[0015] Cellulose is hydrolysed into glucose by the carbohydrolytic cellulases. The prevalent understanding of the cellulolytic system divides the cellulases into three classes; exo-1,4-β- D -glucanases or cellobiohydrolases (CBH) (EC 3.2.1.91), which cleave off cellobiose units from the ends of cellulose chains; endo-1,4-β- D -glucanases (EG) (EC 3.2.1.4), which hydrolyse internal β-1,4-glucosidic bonds randomly in the cellulose chain; 1,4-β- D -glucosidase (EC 3.2.1.21), which hydrolyses cellobiose to glucose and also cleaves of glucose units from cellooligosaccharides.
[0016] The different sugars in hemicellulose are liberated by the hemicellulases. The hemicellulytic system is more complex than the cellulolytic system due to the heterologous nature of hemicellulose. The system involves among others endo-1,4-β- D -xylanases (EC 3.2.1.8), which hydrolyse internal bonds in the xylan chain; 1,4-β- D -xylosidases (EC 3.2.1.37), which attack xylooligosaccharides from the non-reducing end and liberate xylose; endo-1,4-β- D -mannanases (EC 3.2.1.78), which cleave internal bonds; 1,4-β- D -mannosidases (EC 3.2.1.25), which cleave mannooligosaccharides to mannose. The side groups are removed by a number of enzymes; α- D -galactosidases (EC 3.2.1.22), α-L-arabinofuranosidases (EC 3.2.1.55), α- D -glucuronidases (EC 3.2.1.139), cinnamoyl esterases (EC 3.1.1.-), acetyl xylan esterases (EC 3.1.1.6) and feruloyl esterases (EC 3.1.1.73).
[0017] The most important enzymes for use in starch hydrolysis are alpha-amylases (1,4-α- D -glucan glucanohydrolases, (EC 3.2.1.1). These are endo-acting hydrolases which cleave 1,4-α- D -glucosidic bonds and can bypass but cannot hydrolyse 1,6-alpha- D -glucosidic branchpoints. However, also exo-acting glycoamylases such as beta-amylase (EC 3.2.1.2) and pullulanase (EC 3.2.1.41) can be used for starch hydrolysis. The result of starch hydrolysis is primarily glucose, maltose, maltotriose, a-dextrin and varying amounts of oligosaccharides. When the starch-based hydrolysate is used for fermentation it can be advantageous to add proteolytic enzymes. Such enzymes may prevent flocculation of the microorganism and may generate amino acids available to the microorganism.
[0018] In combination with pre-treatment and enzymatic hydrolysis of lignocellulosic biomasses, it has been found that the use of oxidative enzymes can have a positive effect on the overall hydrolysis as well as the viability of the microorganisms employed for e.g. subsequent fermentation. The reason for this effect is the oxidative crosslinking of lignins and other phenolic inhibitors as caused by the oxidative enzymes. Typically laccase (EC 1.10.3.2) or peroxidase (EC 1.11.1.7) are employed either externally or by incorporation of a laccase gene in the applied microorganism.
[0019] Enzymatic hydrolysis of biomass has previously been described. However, in case of lignocellulosic biomasses only material consisting of fibres and particles with an average size below 1 inch (25.4 mm) and furthermore having a relatively low dry matter content, i.e. below 20% (w/w), have successfully been hydrolysed by such a method.
[0020] U.S. Pat. No. 4,409,329 describes hydrolysis of solid cellulose material to sugar, where cellulose is hydrolysed to simple sugars by treating a granular slurry of 3-20% (w/w) solid feed containing 30-80% (w/w) cellulose, with a cellulase enzyme complex. The solid cellulose-containing charge stock had a mean particle size from 0.01 to 1 inch (0.0254-25.4 mm) in diameter. Perforated rotorblades were used for mixing.
[0021] US2002117167A describes enzymatic hydrolysis of hemicellulose in biomass material, comprising solubilizing at least a portion of hemicellulose and hydrolyzing the solubilized hemicellulose to produce at least one monosaccharide. The utilised biomass is preferably aqueous slurry of raw or pre-treated material. The biomass material may be any cellulosic material that includes hemicellulose. The process is described as being especially effective with grain fibres such as corn, wheat, rice, oats or barley.
[0022] US2004005674A describes a process for enzymatic hydrolysis of lignocellulose. Degradation of lignocellulose to sugars comprises contacting the lignocellulose with at least one auxiliary enzyme and at least one cellulase. The lignocellulosic material was grounded (the average fibre size of the material was not further specified) and had a low dry matter content (0.2 g of grounded stover material in 10 ml of the enzyme solution).
SUMMARY OF THE INVENTION
[0023] The present invention relates to a process for liquefaction and saccharification of polysaccharide containing biomasses, having a relatively high dry matter content, preferably above 20%, and preferably consisting of relatively large fibres and particles preferably with a distribution of fibre and particle sizes wherein at least 20% (w/w) of the biomass ranges within 26-70 mm. Furthermore, the process is particularly suited for the liquefaction and saccharification of polysaccharide containing biomasses consisting primarily of starch, refined starch, cellulose, hemicellulose and lignin, e.g. grains or wheat straw. In the case of lignocellulosic biomasses these are preferably pre-treated by subjection to temperatures between 110-250° C. for 1-60 min. in a manner, which secures accessibility of the cellulose to the enzymes and at the same time secures a limited content of fermentation inhibitors in the pre-treated biomass. The present invention combines enzymatic hydrolysis based on the combination of hydrolytic enzymes including a carbohydrolytic enzyme and an oxidative enzyme with a type of mixing relying on the principle of gravity ensuring the application of mechanical forces, primarily shear and tear forces, to the biomasses. Preferred types of mixing are e.g. free fall mixers such as drum mixers, tumble mixers or similar mixing devices.
DESCRIPTION OF THE INVENTION
[0024] Production of concentrated sugar solutions is beneficial in relation to subsequent fermentation or other microbial processes due to improved volumetric productivity and reduced cost of down stream processing. In case of bio-ethanol production, the energy requirement for distillation is significantly reduced if the fermentation broth contains above 4% ethanol (Galbe and Zacchi, 2002). This requires a sugar concentration above 8%, which with most types of lignocellulosic biomasses corresponds to an initial dry matter content above 20%. It is in other words desirable to subject polysaccharide-containing biomasses with high dry matter contents, preferably above 20%, to enzymatic hydrolysis in order to be able to subsequently produce bio-ethanol-containing fermentation broths suitable for distillation of ethanol.
[0025] The processes of the present invention provide a degree of enzymatic hydrolysis of typically 30-50%. However, under optimised conditions even a higher degree of enzymatic hydrolysis may be obtained. The liquefied and saccharificated biomass will consequently contain relatively large amounts of glucose, xylose, cellobiose, lignin, non-degraded cellulose and hemicellulose and still active enzymes suitable for further processing i.e. fermentation processes (ethanol, lactic acid etc.). The liquefied biomass will also be suitable for gasification, hydrogenation, organic synthesis, or production of biogas and feed.
[0026] If the polysaccharide containing biomasses are lignocellulosic the pre-treatment must ensure that the structure of the lignocellulosic content is rendered more accessible to the enzymes, and at the same time the concentrations of harmful inhibitory by-products such as acetic acid, furfural and hydroxymethyl furfural remain substantially low. There are several strategies to achieve this, which all implies subjecting the lignocellulosic material to temperatures between 110-250° C. for 1-60 min e.g.:
Hot water extraction Multi stage dilute acid hydrolysis, which removes dissolved material before inhibitory substances are formed Dilute acid hydrolyses at relatively low severity conditions Alkaline wet oxidation Steam explosion Almost any pre-treatment with subsequent detoxification
[0033] Polysaccharide containing biomasses according to the present invention includes any material containing polymeric sugars e.g. in the form of starch as well as refined starch, cellulose and hemicellulose. Biomasses having a dry matter content above 20% are preferred.
[0034] Relevant types of biomasses for enzymatic hydrolysis and mixing according to the present invention may include biomasses derived from agricultural crops such as e.g.:
Starch e.g. starch containing grains and refined starch Corn stover Bagasse Straw e.g. from rice, wheat, rye, oat, barley, rye, rape, sorghum Softwood e.g. Pinus sylvestris, Pinus radiata Hardwood e.g. Salix spp. Eucalyptus spp. Tubers e.g. beet, potato Cereals from e.g. rice, wheat, rye, oat, barley, rye, rape, sorghum and corn Waste paper, fibre fractions from biogas processing, manure, residues from oil palm processing, municipal solid waste or the like with a similar dry matter content.
[0044] If the polysaccharide containing biomasses are lignocellulosic, the material may be cut into pieces where 20% (w/w) of the biomass preferably ranges within 26-70 mm, before pre-treatment. The pre-treated material has preferably a dry matter content above 20% before entering the mixing device. Besides liberating the carbohydrates from the biomass, the pre-treatment process sterilises and partly dissolves the biomass and at the same time washes out potassium chloride from the lignin fraction.
[0045] The mixing performed in a process according to the present invention serves at least a four-fold purpose.
[0046] Firstly, it ensures close contact between the enzymes used and the polysaccharide containing biomass (substrate), as this will in most cases be insoluble or only very slightly soluble.
[0047] Secondly, the mechanical work performed on the material during the mixing helps tearing larger biomass fibres and particles apart and will therefore assist in increasing the surface area of the material. This will increase the accessibility of e.g. cellulose and hemicellulose to the enzymes used. To further increase the mechanical work on the material, steel balls or similar means that will collide with the material might be added to the drum.
[0048] Thirdly, the mixing of the material prevents local accumulation of high cellobiose concentration that—as is well known for a person skilled in the art—can inhibit e.g. cellulase enzymes, especially the cellobiohydrolases.
[0049] Fourthly, an important characteristic of the cellulase enzymes is the influence of cellulose binding domains (CBD) on the enzyme performance. CBD's are functional parts of cellulose degrading enzymes. The CBD enables adhesion of the water-soluble enzyme onto an insoluble substrate surface (cellulose). The close association between the enzyme and cellulose provided by the CBD enhances the catalytic rate and stability of the enzyme. To hydrolyse cellulose, the enzyme must change the position of the CBD on the cellulose chain. It is believed that mechanical action, i.e. mixing, is important for the movement of the CBD and consequently for the enzymatic action of the enzymes along the cellulose chain.
[0050] In addition to the above it should be noted that enzymatic hydrolysis of biomass has traditionally been conducted in stirred tank reactors equipped with impellers (e.g. Rushton turbine or Intemig impeller) mounted on a centrally placed impeller shaft similar to what is used in the fermentation industry. Due to this equipment, solutions of high viscosity, very sticky or very dry material cannot be stirred efficiently but will result in zones with very poor or no mixing. Furthermore, stirrings of such solutions require very large energy inputs, which is detrimental to the process economy. Operating with polysaccharide containing biomasses this has previously restricted the upper possible limit to app. 20%. The gravity based mixing principle according to the present invention overcomes this problem and may be used for polysaccharide containing biomasses with a dry matter content up to 80%, preferably 20-50%. The principle of gravity mixing according to the present invention can easily be scaled up and be applied for all kinds of biomasses, besides refined starch, containing up to more than 80% cellulose.
[0051] Unlike conventional stirred tank reactors traditionally used for enzymatic hydrolysis, a gravity based mixing principle, i.e. a drum mixer, a mixer with a rotary axis lifting the biomass or similar mixing devise utilising a free fall principle, at the same time enables an efficient mixing even with small power inputs and high dry matter contents and furthermore performs a mechanical processing/degradation through the forces of gravity including shear and tear forces between material and drum as well as the forces resulting from the impact between falling material and the bottom of the drum and at the same time positively effects the influence of cellulose binding domains (CBD) on enzyme performance.
[0052] Although processing of non-miscible plant materials, such as e.g. polysaccharide containing biomass with relatively high dry matter content and large average fibre and particle size, is known from solid-state fermentation or bioreactors, where tumble type mixers are used for blending (Giovanozzi et al. 2002), this principle has not previously been implemented in a dedicated liquefaction/saccharification process or a bio-ethanol fermentation process.
[0053] The present invention provides a process for processing of biomasses at relatively high dry matter contents, e.g. dry matter contents between 20-80%, preferably between 20-50%. Furthermore, the process according to the present invention ensures efficient liquefaction and saccharification enabling the direct use of the end product in e.g. fermentors.
[0054] Enzymes capable of effecting a conversion of starch, cellulose and hemicellulose or parts thereof into glucose, xylose and cellobiose are added to the biomass either in native form or in form of microbial organisms giving rise to the accumulation of such enzymes. The pH and the temperature of the biomass are adjusted with reference to the pH-optimum and the temperature optimum of the enzymes applied.
[0055] Depending on enzyme loading, the biomass will be liquefied and saccharified to a liquid without any or only with few remaining large fibres and particles within 3-24 hours. Adding a glucose metabolising microorganism at any given time during the hydrolysis and liquefaction may enhance the degree of enzymatic hydrolysis as inhibitory enzyme products are thereby removed.
DETAILED DESCRIPTION OF THE INVENTION
[0056] A process according to the present invention can be performed using the following preferred technical parameters.
Dry matter content: 20-80%, preferably 25-70%, more preferably 25-60%, even more preferably 25-50% or 25-40% and most preferably 25-35% Distribution of fibre and particle sizes of lignocellulosic biomass: 0-150 mm, preferably, 5-125 mm, more preferably, 10-100 mm, even more preferably 15-90 mm or 20-80 mm and most preferably 26-70 mm. The preferred distribution of fibre and particle sizes is defined as at least 20% (w/w) of the lignocellulosic biomass ranging within the preferred interval.
[0059] If the polysaccharide containing biomass is lignocellulosic, it has to be pre-treated e.g. by a hot water extraction. If a hydro thermal pre-treatment is chosen the following technical data are preferred:
Pre-treatment temperature: 110-250° C., preferably 120-240° C., more preferably 130-230° C., more preferably 140-220° C., more preferably 150-210° C., more preferably 160-200° C., even more preferably 170-200° C. or most preferably 180-200° C. Pre-treatment time: 1-60 min, preferably 2-55 min, more preferably 3-50 min, more preferably 4-45 min, more preferably 5-40 min, more preferably 5-35 min, more preferably 5-30 min, more preferably 5-25 min, more preferably 5-20 min and most preferably 5-15 min Dry matter content after pre-treatment of at least 20 w/w %.
[0063] Enzymatic treatment of polysaccharide containing biomasses in a gravity mixer:
[0064] If a vessel based on the free fall mixing concept in the form of a reactor with a horizontal placed stirrer shaft lifting the biomass or similar mixing devise is used, the following technical data are preferred:
Rotational speed: 0-30 rpm, preferably 0-20 rpm, more preferably 0-15 rpm even more preferably 0-10 rpm and most preferably 0-5 rpm. Rotation with periodically alternated rotating direction. Rotation in pre-defined intervals.
[0068] The optimal rotational speed will depend on the volume of the vessel, the preferred rotational speed may thus be relatively high when the process is carried out in a relatively small vessel, while it may be relatively low when the process is carried out in a relatively large vessel.
Enzymes for lignocellulosic biomass:
Cellobiase (e.g. Novozym 188) Cellulase (e.g. Celluclast 1.5 FG L)
Enzyme loading in Filter Paper Units (FPU)/g DM. 1 FPU equals the amount of enzyme necessary to hydrolyse 1 μmol/min of glycosidic bonds on Whatmann # 1 filter paper, under specified conditions well known to a person skilled in the art. However, enzymatic activity could in principle be supplied in any conceivable form including through the addition of microorganisms giving rise to the desired enzymatic activity: corresponding to 0.001-15 FPU/g dry matter, preferably 0.01-10 FPU/g dry matter, more preferably 0.1-8 FPU/g dry matter, more preferably 1-7 FPU/g dry matter and most preferably less than 6 FPU/g Enzymes for starch containing biomass:
Enzymes in the processing of starch: alpha-amylases and glucoamylases
Treatment time for enzymatic hydrolysis: 0-72 hours, preferably 1-60 hours, more preferably 2-48 hours and more preferably 3-24 hours such as 4-24 hours, such as 6-24 hours, such as 8-24 hours, such as 10-24, such as 12-24 hours, such as 18-24 hours or 22 hours Temperature for enzymatic hydrolysis. Adjusted with reference to the optimum temperatures of the applied enzymatic activities: 0-105° C., preferably 10-100° C., more preferably 15-90° C., more preferably 20-80° C., more preferably 25-70° C. and most preferably 30-70° C. such as 40-45° C. or room temperature. pH of biomass. Adjusted with reference to the optimum pH of the applied enzymatic activities: 3-12, such as 5-10, such as 6-9, such as 7-8 and preferably 4-11 The enzymatic treatment can be conducted as a batch, fed batch or a continuous process.
EXAMPLE 1
Enzymatic Hydrolysis in Laboratory Scale
[0079] Pressed pre-treated wheat straw with an average size of approximately 40 mm (counter-current water extraction at 180-200° C. for 5-10 min., water and dry matter flow ratio of 5:1) corresponding to 25 g dry weight (=67.0 g pre-treated straw) was put into a plastic bag. 0.75 mL of Novozym 188, 3.75 mL of Celluclast 1.5 FG L and 11.9 mL of 50 mM sodium citrate buffer, pH 5.0, was mixed and sprayed onto the straw. This resulted in a final dry matter content of 30%. The enzyme loading corresponded to 10 Filter Paper Units (FPU)/g DM.
[0080] The mixer consisted of a drum (1.0 m long and 0.78 m in diameter) with 5 internal ribs along the long axis to ensure proper mixing of the material. The drum rotated along the horizontal axis with a speed of 26 rpm. The mixing/hydrolysis of the material was performed for 18-24 hours at room temperature. This resulted in a thick paste without any remaining large fibres. A control bag with the same enzyme loading but no mixing showed no sign of degradation of the straw.
[0081] Part of the resulting material after the enzymatic hydrolysis for 24 hours (an amount corresponding to 29 g dry matter) was diluted to 15% dry matter in a blue cap bottle and yeast (Baker's yeast, De Danske Spriffabrikker) was added. The bottle was closed by an air lock and placed for 72 hours at 30° C. with stirring at 500 rpm. The resulting liquid contained 33 g/L of ethanol, 10 g/L of xylose. No glucose was detected indicating that the yeast was capable of utilising all glucose produced during the hydrolysis. Assuming an ethanol yield on glucose of 0.5 g ethanol per g glucose this corresponded to conversion of 70% of the originally cellulose.
EXAMPLE 2
Enzymatic Hydrolysis at Pilot Scale
[0082] Pressed pre-treated wheat straw with an average size of approximately 40 mm (pre-treated by counter-current water extraction at 180-200° C. for 5-10 min. with a water and dry matter flow ratio of 5:1) corresponding to 7 kg DW (=20 kg pre-treated straw) was put into a conventional rotary cement mixer, with a horizontal axis tilted about 10 degrees. The mixer had 2 internal ribs along the long axis to ensure mixing of the material. A lid was mounted on the opening to avoid evaporation from the mixer. The mixer drum rotated along the horizontal axis with a speed of 29 rpm.
[0083] 200-1150 mL of Celluclast 1.5 FG L and 40-225 mL of Novozym 188 were added to the straw. This resulted in a final dry matter content of 30%. The enzyme loading corresponded to 3-15 FPU/g DM. The pH was adjusted to 4.8 to 5.0 by addition of sodium carbonate.
[0084] The cement mixer was heated to 40-45° C. by use of a fan heater. The mixing/hydrolysis of the material was performed for 22 hours. Depending on enzyme loading this resulted in a more or less viscous liquid without any remaining large fibres. The pre-treated straw was degraded to a paste in app. 3-5 hours. After 5-24 hours of mixing the paste was changed to a viscous liquid. Control experiments with pre-treated wheat straw only or wheat straw pre-treated at only 160° C. but using the same enzyme loading showed no sign of liquefaction of the straw.
[0085] Simultaneous saccharification and fermentation was performed by adding yeast to the cement mixer after 24 hours of hydrolysis at 40-45° C. using an enzyme loading of 10-15 FPU/g DM. The temperature was allowed to cool to below 35° C. and compressed yeast (Baker's yeast, De Danske Spritfabrikker) was added to a concentration of approximately 1% (w/w) based on initial dry matter of straw. The saccharification and fermentation was continued for 48 hours at 25° C.
[0086] The resulting material was centrifuged for 15 min at 2500 rpm. The supernatant was filtered through a 0.45 μm filter and analysed for sugars on HPLC. At an enzyme load of 15 FPU/g DM, the supernatant contained 70 g/L of glucose, 30 g/L of xylose after 24 hours of hydrolysis. This corresponded to 50% hydrolysis of the cellulose and hemicellulose originally present in the straw. The simultaneous saccharification and fermentation using an enzyme loading of 10 FPU/g DM resulted in 42 g/L of ethanol and 30 g/L of xylose.
EXAMPLE 3
Liquefaction, Hydrolysis and Fermentation
[0087] The hydrolysis reactor was designed in order to perform experiments with liquefaction and hydrolysis solid concentrations above 20% DM ( FIG. 1 ). The reactor consisted of a horizontally placed drum divided into 5 separate chambers each 20 cm wide and 60 cm in diameter. A horizontal rotating shaft mounted with three paddlers in each chamber was used for mixing/agitation. A 1.1 kW motor was used as drive and the rotational speed was adjustable within the range of 2.5 and 16.5 rpm. The direction of rotation was programmed to shift twice a minute between clock and anti-clock wise. A water-filled heating jacket on the outside enabled the control of the temperature up to 80° C.
[0088] The chambers were filled with pressed pretreated wheat straw with an average size of approximately 40 mm (pre-treated by counter-current water extraction at 180-200° C. for 5-10 min. with a water and dry matter flow ratio of 5:1) and water to give an initial DM content of 20 to 40%. Celluclast 1.5 FG L and Novozym 188 in 5:1 ratio were added to give an enzyme loading of 7 FPU per g DM. The liquefaction and hydrolysis was performed at 50° C. and pH 4.8 to 5.0. The mixing speed was 6.6 rpm. Simultaneous saccharification and fermentation (SSF) experiments were performed by lowering the temperature to 32° C. after 8 h of liquefaction and hydrolysis and following the addition of 15 g of compressed baker's yeast (De Danske Spriffabrikker) per kg of initial DM.
[0089] Liquefaction and hydrolysis was possible with initial DM content of up to 40% DM ( FIG. 2 and 3 ). With initial 40% DM it was possible to reach glucose concentrations of 80 g kg −1 after 96 h. It was also possible to operate the process as SSF ( FIG. 3 ), thereby reducing the product inhibition of the cellulases caused by the glucose accumulation. It was possible to ferment the hydrolysates with up to 40% initial DM content using normal baker's yeast. Under not fully anaerobic conditions the ethanol yield was 80, 79, 76, 73 and 68% of what was theoretically obtainable at 20, 25, 30, 35 and 40% DM, respectively.
EXAMPLE 4
Whole Crop Liquefaction, Saccharification and Fermentation
[0090] Lignocellulosic and starch containing biomass can be processed simultaneously using gravity mixing and a mixture of cellulases, hemicellulases and amylases. The lignocellulosic biomasses may be derived from agricultural crops consisting of e.g. corn stover, straw e.g. from rice, wheat, rye, oat, barley, rye, rape and sorghum, tubers e.g. beet, potato, cereals from e.g. rice, wheat, rye, oat, barley, rye, rape, sorghum, wood consisting of softwood e.g. Pinus sylvestris, Pinus radiata , hardwood e.g. Salix spp., Eucalyptus spp., municipal solid waste, waste paper and similar biomasses.
[0091] The hydrolysis reactor described in example 3 was used for the experiments. Wheat straw (primarily a lignocellulose source) was pretreated using counter-current water extraction at 180-200° C. for 5-10 min. with a water and dry matter flow ratio of 5:1. Wheat grain (primarily a starch source) was dry milled using a Kongskilde roller mill. The wheat grain and pretreated straw with an average size of approximately 40 mm was mixed in a 1:1 ratio on a dry basis. DM was adjusted to between 30 and 40% by addition of water. Celluclast 1.5 FG L and Novozym 188 in a 5:1 ratio were added to give an enzyme loading of 7 FPU per g DM of straw. Hydrolysis of starch was carried out using cold mash enzyme NS50033 (Novozymes A/S, Bagsvaerd, Denmark) at a loading of 3.5 g per kg of wheat grain. The liquefaction and hydrolysis was performed at 50° C. and pH 4.8 to 5.0. After 8 h, the temperature was lowered to 34° C. and 15 g of compressed baker's yeast (De Danske Spriffabrikker) was added per kg of initial DM. An experiment with straw only at 30% DM was run in parallel.
[0092] Mixing straw with grain resulted in a fast initial accumulation of glucose in the liquefaction and hydrolysis step compared to applying straw only ( FIG. 4 ). After 96 h of liquefaction and SSF the ethanol concentration was 41 g kg −1 using only wheat straw as the only substrate ( FIG. 4 ). In the experiment with straw and grain the ethanol concentration reached 68 g kg −1 .
EXAMPLE 5
Low Temperature Liquefaction of Starch or Starch Containing Materials
[0093] A process according to the present invention can also be applied for low temperature processing of refined starch or starch containing materials (e.g. beet, potato, cereals from e.g. rice, wheat, rye, oat, barley, rye, sorghum). According to example 4, heat pre-treatment of the grain is not necessary for liquefaction and hydrolysis of starch. Dry milling is on the other hand generally used for pre-treatment of starch containing grains. Dry milled grains with a dry matter content of 20-60% are loaded into the gravity mixer. Cold mash enzyme NS50033 (Novozymes A/S, Bagsvaerd, Denmark) or alpha-amylase and glucoamylases are added simultaneously. A full liquefaction and saccharification of the starch is then possible in a one-pot process. Temperature and pH ranges during the enzymatic hydrolysis process are defined by the enzymes and will be in the range of 25-60° C., preferably 40-55° C., and pH 3-12, preferably pH 3-8, respectively.
[0094] The process may be combined with SSF.
CITED LITERATURE
[0000]
Galbe, M., Zacchi, G. (2002). A review of the production of ethanol from softwood. Appl. Microbiol. Biotechnol. 59:618-628.
Giovannozzi-Sermanni, G., D'Annibale, A., Perani, C., Porri, A., Falesiedi, G. (2002). Solid-state bioreactors for the sustainability.
http://www.unitus.it/dipartimenti/dabac/progetti/ssbioreactors/solidstatebioreactor.htm
Gregg, D., Saddler, J. N. (1995). Bioconversion of lignocellulosic residues to ethanol: Process flow-sheet development. Biomass Bioenerg. 9:287-302.
Mais, U., Esteghalalian, A. R., Saddler, J. N. (2002). Influence of mixing regime on enzymatic saccharification of steam-exploded softwood chips. Appl. Biochem. Biotechnol. 98-100:463-472.
U.S. Pat. No. 4,409,329
US2002117167A
US2004005674A | The present invention relates to a process for liquefaction and saccharification of polysaccharide containing biomasses, having a relatively high dry matter content. The present invention combines enzymatic hydrolysis with a type of mixing relying on the principle of gravity ensuring that the biomasses are subjected to mechanical forces, primarily shear and tear forces. Furthermore, the present invention relates to the further utilisation of such processed biomasses, e.g. for subsequent fermentation into bio-ethanol, bio-gas, specialty carbohydrates for food and fees as well as carbon feedstock for processing into plastics and chemicals. | 2 |
FIELD OF THE INVENTION
The present invention relates to a method for removing casings from sausages and, in particular, for removing cellulosic casings from sausages such as frankfurters and the like.
BACKGROUND OF THE INVENTION
It is well known that certain types of sausages such as frankfurters, are made on automatic stuffing machines. These machines stuff an uncooked sausage emulsion into a long tubular casing while simultaneously forming the casing into links. Typically, the casing is of a regenerated cellulosic and the individual links are formed by twisting the casing during stuffing. The individual links also may be formed by pinching the stuffed casing. In any event, the result is a string of links that may be up to 50 meters or more long. The string is processed to cook or cure the emulsion and then the casing is removed to produce individual sausages ready for retail packaging. Casings for use in making linked sausages generally are made of a pure regenerated cellulose and are produced in sizes which range from about 14.5 to 45 mm in diameter.
Peeling the cellulose casing from the sausages has presented particular problems to the art. In this respect, peeling aid solutions have been developed. These peeling aid solutions are applied to the inner wall of the casing by the casing manufacturer. Generally the solutions include compounds that create an aqueous film between the surface of the sausage and the casing. This film reduces the adhesion of the casing to the surface of the sausage and thus facilitates the peeling of the casing from the sausage. The effect of such peeling aids varies depending upon the particular formulation of the emulsion being stuffed and the processing conditions. Accordingly, it is not unusual for casing manufacturers to offer several different peeling treatments to accommodate the particular needs of its customers. The application of a peeling solution to the interior of the cellulose casing also requires additional materials and manufacturing steps that add to the casing cost.
A typical method used by the sausage maker to remove the cellulose casing from the sausages is to run the string of links through a mechanical peeler. The peeler has a knife edge that longitudinally slits the casing. The string then passes over a perforated wheel connected to a vacuum source. The vacuum pulls the casing around the wheel and away from the sausages while the sausages are allowed to pass tangentially off the wheel. This separates the casing and frees the individual sausage links. The peeling apparatus also commonly exposes the string of sausages to steam to help loosen the casing from the sausage and facilitate peeling. Mechanical peelers of this type are shown in U.S. Pat. Nos. 3,698,973; 4,118,828; and U.S. Pat. No. 4,414,707 among others.
Mechanical peelers while comprising the present preferred method for peeling sausages, have several drawbacks. For example, the knife edge becomes dull and must be replaced periodically. If the knife edge is improperly positioned, it either will not cut through the casing or it may cut too deeply and score the sausage. If the casing is not cut, it can not be separated from the sausage. Thus, the knife edge must be critically controlled for bearing pressure and placement with respect to the casing surface in order to properly slit the casing without deeply scoring the surface of the sausage. The use of steam also is an objectionable part of the process even though it often is necessary for high percentage peeling. Use of steam results in high utility costs. The steam condenses and the free-standing water which results makes for an unsafe work environment. Also, the condensed steam collects on the peeled sausages and is a source of contamination. The problems caused by condensation is particularly acute if the steam peeling is conducted in a refrigerated environment.
Mechanical peelers and the use of casing treatments are not 100% effective. Often shards or bigger sections of casing remain on the peeled link that must be removed manually. Casing manufactures often add color or stripes to the cellulose casing to facilitate spotting the casing piece on the peeled sausage. These stripes or colors further add to the casing cost.
Disposal of the spent casing after removal from the sausages is another problem for the sausage manufacturer. Typically the spent casing is sent to a land fill. This is costly in terms of hauling and landfill charges.
In view of the drawbacks of methods currently in use for peeling cellulose casings from sausages, the need exists for an improved method for removing the casing from frankfurters that does not depend upon either chemical treatments applied to the inner surface of the casing or upon contact of the processed sausage with steam to facilitate the separation of the cellulose casing from the sausage. The need further exists for a method that eliminates the need for mechanical peelers to remove a cellulose casing from the sausages.
Accordingly, one object of the present invention is to provide an improved method for removing cellulose casings from sausages.
Another object of the present invention is to provide a method for removing cellulose casing from sausages that avoids the need for applying a product-specific easy peeling chemical treatment to the inner surface of the casing.
A further object of the present invention is to eliminate the use of mechanical peelers and steam assisted peeling to remove cellulose casings from frankfurter sausages and the like.
Yet another object is to provide a method of removing cellulose casing from sausages that eliminates the need for land filling the spent casing.
SUMMARY OF THE INVENTION
The present invention is a method of removing a cellulosic food casing from about a stuffed sausage by action of food grade enzymes or enzymes which are generally recognized as safe (GRAS), and which have the ability to hydrolyze cellulose and hemicellulose. This can be accomplished by contacting the string of processed sausages with a solution containing the enzyme or enzyme blend such as by showering the string or passing it through a tank containing the solution. Enzymes particularly suited to metabolize a cellulose casing include cellulase and xylanase. It has been found that a few hours in contact with a solution containing the appropriate enzyme or enzyme blend is sufficient to permit the enzyme to metabolize the cellulose casing so as to rid the sausage of its casing.
It is not necessary for purposes of the present invention to have the cellulose casing completely metabolized by the enzyme in order to remove the casing from the sausage. It is sufficient that the enzyme degrade the casing to the point where either the sausage and casing can be separated or casing pieces remaining on the sausage can be removed by rinsing.
The sausages, once they are rid of the casing, are considered to be "skinless". They are then collected from the solution and packaged for the retail trade. If necessary, the skinless sausages are rinsed prior to packaging. The solution which remains after the skinless sausages are collected contains the by-products of metabolizing the cellulose including glucose, xylose, cellobiose, and other oligosaccharides. The solution may also contain bits of cellulose if the metabolism has not gone to completion. This solution either is discharged to the sewer, processed to recover the glucose and other by-products, or is processed for use as an animal feed. Preferably, processing of the solution includes recovery of the enzyme for reuse.
Accordingly, the method of using an enzyme to metabolize the cellulose food casing on the sausage addresses and resolves the problems associated with applying product-specific easy peel treatments to the casing interior, mechanically peeling the casing and dealing with the spent casing after peeling.
Several enzymes that have been found suitable are MULTIFECT™ CL, MULTIFECT™ GC, and MULTIFECT™ XL all sold by Genencor Corporation of Rochester, N.Y. These enzyme formulations are GRAS and are derived from selected strains of Trichoderma longibrachiatum (formerly Trichoderma reesei).
At present, the only commercial process for manufacture of a cellulose casing involves use of the well-known viscose process. In the viscose process a natural cellulose is contacted with a strong base to produce alkali cellulose. The alkali cellulose then is reacted with other chemicals to produce cellulose xanthate, a soluble cellulose derivative. The xanthate is extruded as a tube into an acid bath. The acid reacts with the xanthate to regenerate the cellulose. Thus, with the viscose process, there is a first chemical reaction to create a soluble cellulose derivative and a second chemical reaction to regenerate the cellulose from the derivative.
More recently, a solution process has been adapted to the production of cellulose casing. In a solution process a cellulose casing is formed by a method involving the direct dissolution of a natural cellulose, such as wood pulp, by a cellulose solvent, such as N-methyl-morpholine-N-oxide (NMMO). The solution is extruded as a tube into a bath of a non cellulose solvent, such as water, to extract the solvent and precipitate or regenerate the cellulose. Thus when using a solution process, a non derivitized cellulose casing is formed in contrast with a derivitized cellulose casing formed using a process such as the viscose process. Reference is made to U.S. Pat. Nos. 5,277,857 and 5,451,364 for more details of a method for forming a casing of a non derivitized cellulose. For purposes of the present invention a "non derivitized" cellulose means a cellulose which has not been subjected to covalent bonding with a solvent or reagent but which has been dissolved by association with a solvent or reagent through Van der Waals forces and/or hydrogen bonding.
Unexpectedly, it has been found that the enzyme is more effective against a non derivitized cellulose casing than against a derivitized cellulose casing. It is not understood why the enzyme metabolizes a casing of non derivitized cellulose faster than a casing of a derivitized cellulose. One possible reason is that the derivitized cellulose may contain trace amounts of a sulfur compound that may inhibit enzyme activity. These sulfur compounds commonly evolve during the chemical reaction for regenerating the derivitized cellulose. U.S. Pat. No. 5,702,783, discloses that the crystalline structure of non derivitized cellulose casing is different from the crystalline structure of a casing of derivitized cellulose. This difference in crystalline structure may be the reason why the non derivitized cellulose is more susceptible to enzymatic metabolism.
For what ever the reason, it has been found that non derivitized cellulose is more susceptible to enzyme action than is a derivitized cellulose. For example, a non derivitized cellulose casing is opened by enzyme action in as short a time as 0.5 hours and is made completely soluble by the enzyme in as short a time as five hours. In contrast, a derivitized cellulose casing takes longer to be opened by enzyme action and is made completely soluble in 5.5 to 7.0 hours. Thus, a preferred embodiment of the invention involves the use of a non derivitized cellulose casing to make the sausages.
Accordingly, the present invention may by characterized in one aspect thereof be a method for removing a cellulose casing from sausages such as frankfurters and the like comprising contacting the encased sausage with a solution containing a food approved enzyme under conditions permitting the enzyme to metabolize an amount of casing sufficient to degrade the casing to such an extent that the casing separates from the sausage thereby producing a substantially casing-free sausage.
DESCRIPTION OF THE DRAWINGS
The sole FIGURE is a schematic representation showing apparatus for carrying out the method of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawing, apparatus for caring out the method of the present invention is generally indicated at 10. The apparatus includes container 12 that is open at its upper end 14. The bottom and side walls of the container each have a plurality of openings 16. Container 12 is arranged for movement into and out of a vat 18. The vat preferably is provided with a temperature control means 20 and contains a solution 22 that includes a food approved enzyme or enzyme blend capable of metabolizing cellulose and/or hemicellulose.
In operation, a string of frankfurters 24 is placed into the container 12. The frankfurter string consists of cooked frankfurters encased in a cellulose food casing. Preferably, the frankfurters are fresh from the processing operation that has cooked the emulsion stuffed into the cellulose casing. As an alternative, the string may be divided by cutting the connective casing between the frankfurters so the cellulose encased frankfurters of the string are separated one from another.
The container 12 is lowered into the vat. The openings 16 allow the enzyme-containing solution 22 in the vat to enter and fill the container. The container is kept in the vat for a time sufficient to permit the enzyme to metabolize the cellulose casing on the frankfurter. If desired, means (not shown) may be provided to force the circulation of the enzyme-containing solution through the container. The frankfurters can remain in contact with the enzyme until the cellulose is fully metabolized. However, as metabolism progresses, the casing is degraded to such an extent that pieces and flecks of casing are easily washed or otherwise removed from the frankfurter. Accordingly, the complete removal of the casing from the frankfurter does not depend on fully metabolizing the casing.
After the cellulose has been metabolized, the container is lifted from the vat. The enzyme-containing solution drains from the openings 16 and back into the vat as the container is lifted. In this fashion the frankfurters, now casing-free, are recovered from the solution. They are then removed from the container, rinsed if necessary to remove any residual casing bits and then passed on for retail packaging.
The solution that remains in the vat is glucose rich as a result of the metabolism of the cellulose by the enzyme and likely contains flecks of casing as well as other metabolism by-products such as monosaccharides (xylose) and oligosaccharides. This solution can be further processed to concentrate or recover the glucose and other by-products for other uses, such as for example, use as an animal feed. Enzymes also can be recovered from the solution for reuse.
It is known that by-products of the cellulose digestion such as glucose, may inhibit the action of the enzyme. Accordingly, to maintain enzyme activity, the enzyme-containing solution 22 as it becomes contaminated by the by-products of the cellulose metabolism, may be circulated through an ultra filtration unit indicated at 26. In the ultra filtration unit, the glucose and other by-products such as oligosaccharides are removed and then the filtered, enzyme -containing solution is returned to the vat 18.
It has been found that the area of the cellulose casing that undergoes the fastest metabolism by the cellulase is along a seam in the casing believed to be the extrusion fold. The extrusion fold is a longitudinal fold produced during the manufacture of the casing. The fold occurs as the casing, in a gel state, is laid flat and passed between nip rollers prior to drying. The cellulose casing is probably weakest along the extrusion fold which may account for the faster metabolism in this area.
The metabolism of the casing by the enzyme first opens a seam along the extrusion fold. At this point the casing is not completely removed from the casing. However, while it is preferred to allow the enzyme to completely metabolize the casing, the opening of a seam does provide an opportunity to shorten the cycle time of the process. In this respect rather than wait until all of the cellulose casing has been metabolized, the frankfurters can be removed from the container 12 when the seam is opened in the casing. Either the opened casing will drop from the sausages or a pressure wash can be used to remove the casing from about the sausages.
Several tests were conducted to demonstrate the method of the present invention. A first test was conducted for screening purposes to determine the optimal conditions for the enzyme. In the test, spent casing of a conventional derivitized cellulose was exposed to various concentrations of an enzyme active against cellulose. The spent derivitized cellulose casing consisted of NOJAX® cellulose casing made by Viskase Corporation recovered from a conventional mechanical peeling machine. In the screening tests, the enzyme used was a MULTIFECT™CL enzyme sold by Genencor International, Inc. According to the manufacturer, this enzyme is generally recognized as safe (GRAS). It is a fungal cellulase derived from a selected strain of Trichoderma reesei and its activity is standardized on the basis of its ability to metabolize carboxymethylcellulose (CMC) to glucose. The minimum CMC activity of this enzyme is represented as being 2,000 IU/ml wherein one IU (International Unit) of activity liberates 1 μmole of reducing sugar (glucose equivalent) in one minute at 50° C. and pH of 4.8. The enzyme is said to degrade crystalline or amorphous cellulose.
In the screening test, three enzyme solution samples were prepared by adding 0.25 gm/liter, 0.5 gm/liter and 2 gm/liter respectively of the enzyme to 100 grams of a pH 5 buffer solution at a temperature of about 50° C. Six samples were prepared at each concentration giving a total of 18 samples. The spent casing was not washed to remove any fats or oils remaining on the inner surface of the casing after peeling. However, the spent casing was dried in order to more accurately measure the amount of cellulose being used in the test.
Ten grams of the dried spent cellulose casing were added to each sample. After different time intervals samples were centrifuged for thirty no minutes at 3000 RPM to recover solids. The solids were weighed and ten grams of the remaining liquid fraction from each sample were analyzed for glucose content. Glucose is not the sole by-product of the metabolism of the cellulose by the enzyme. As noted above, other compounds such as xylose and oligosaccharides are produced. However, the amount of glucose is a convenient indicator of the efficiency of the enzyme to metabolize the cellulose.
After about three hours in the highest concentration solution of 2.0 gm/liter, the solids content of the original 10 gm sample was reduced by 2 gm and the glucose content of the liquid fraction increased to 1704 ppm, which translates to 1.7% of the dry casing as being converted to glucose. After 28 hours the solids content was reduced to about 6 gm with the glucose content increasing to about 8305 ppm. This means that about 8.31% of the dry casing was converted to glucose. While reducing the solids content by almost one-half over a period of 28 hours is significant, it is not an indication that enzyme action could function as a peeling mechanism.
Similar tests conducted at a pH of 5.6 produced results not as good as those conducted at a pH 5. Other tests conducted at pH 5 and at temperatures of 400 and 60° C. were not as good as those conducted at 50° C.
The screening indicated that the enzyme appeared to be most effective against the cellulose casing at a temperature of 50° C. and a pH of 5. Accordingly, further tests were conducted under these conditions.
The enzyme concentration was raised to 20 gm/liter to increase the speed of the cellulose degradation by the enzyme. Five liter samples of a buffered (pH 5) solution were prepared, each containing a 20.0 gm/liter concentration of the MULTIFECT™ CL enzyme. One kilogram of frankfurters, comprising a string of about fifteen links was place in each of the five liters of solution. The solutions then were heated to a temperature of about 50° C. Frankfurters stuffed in casings of both derivitized and non derivitized cellulose casings were tested separately. The samples were observed over a period of about four hours and during this time, some metabolism of both casings was observed. The samples were left over night for a total time in the enzyme solution of about eighteen hours. By morning, the casing in both cases was completely metabolized and the individual sausages were casing-free. Glucose analysis showed that after eighteen hours, about 86% of the non-derivitized cellulose had been converted to glucose and 83.2% of the derivitized cellulose had been converted.
There are various reasons why the enzyme was slow to metabolize the spent casing in the screening test but successfully metabolized all of the casing (both the derivitized type and the non derivitized casing) in less than eighteen hours. One reason is the higher enzyme concentration. Another possible contributing factor is that the contact of the enzyme with the fats and oils from the spent casing interfered with the action of the enzyme. In the second test which used stuffed casing, the enzyme only could contact the outer surface of the casing which is relatively free of fats and oils.
Given the results of the second test, a third test was conducted in order to determine more precisely, the time taken to metabolize the samples. In the third test, the test conditions of the second test were repeated except that the samples were inspected at intervals of 10, 25, 50, 80, 140 and 170 minutes.
After ten and twenty-five minute intervals there appeared to be no visual change in either type of casing. After about fifty minutes, both types of casing appeared to tear more easily indicating a weakening of the cellulose structure by the enzyme. This weakening was most apparent along the extrusion fold.
After about 170 minutes, the non-derivitized casing was metabolized along the extrusion fold to such an extent that a seam had opened allowing easy removal of sausages from the casing. Metabolism of the extrusion fold of the derivitized cellulose casing was noticed but the casing was still intact and dio no seam had opened.
The test was allowed to continue. By five hours, a seam had opened in the derivitized cellulose casing allowing removal of some sausages from the casing. After about seven hours, almost all of the non derivitized cellulose casing had been metabolized leaving the individual sausages clean and free of casing, whereas the derivitized cellulose still was mostly intact about the sausages.
Based on these tests it is apparent that an enzyme having the ability to hydrolyze cellulose is effective for removing cellulose casing from a stuffed sausage such as a string of frankfurters. This is particularly the case when using a casing made with a non derivitized cellulose because the enzyme appears to attack and is able to metabolize a non derivitized cellulose casing much faster than a derivitized cellulose casing. Thus the use of an enzyme to remove casing from a string of stuffed sausages is a viable alternative to mechanical peeling.
An additional screening test using the conditions noted above, was conducted using MULTIFECT™ XL enzyme. MULTIFECT™XL is identified by the manufacturer to be a cellulase enzyme complex with endoxylanase activity. The enzyme is derived from a strain of Trichoderma reesei and is said to have minimum activity of 445 XAU where the XAU (Xylanase Activity Unit) is based on the release of Remazol Brilliant Blue-dyed oat spelt xylan at pH 4.5 at 40° C. in ten minutes using an endoxylanase reference standard.
The same spent NOJAX® casing was used in the tests with a solids and glucose analysis being made at intervals of 1, 2, 20, and 24 hours. At a pH of 5 and temperature of 50° C., the enzyme reduced the initial ten gram sample of casing to 6.6 grams in twenty hours and to 6.4 grams in twenty-four hours. However, glucose analysis showed that after 24 hours, 17.13% of the cellulase had been converted to glucose as opposed to an 8.31% conversion for the MULTIFECT™CL enzyme in twenty-eight hours (see above). Since cellulose casing is not known to contain a large percentage of xylan, the amount of glucose produced confirms that the XL enzyme does include a cellulase. From this screening, and based on the amount of cellulose converted to glucose, it is apparent that both types of enzymes (cellulase and xylanase), working together, are more effective in metabolizing the cellulose casing than a cellulase alone.
In another test, frankfurters in casings of both derivitized and non derivitized cellulose casings were exposed to different enzymes. In all cases the enzyme concentration was 20 gm/liter at pH 5 and 50° C. Two solutions were prepared, one containing the MULTIFECT™ XL and another containing a 50/50 blend of the MULTIFECT™ XL with MULTIFECT™ CL. Strings of ten frankfurters each (about 0.5 kilograms) were placed in beakers containing 2.5 liters of each buffered enzyme solution heated to 50° C. Periodically, visual observations were made to determine the extent of the cellulose degradation.
From a purely visual observation, there was little difference between the action of the XL alone and the XL/CL blend on the non derivitized cellulose casing. After 0.5 hours in the XL solution the casing was broken along a longitudinal seam. After 1.5 hours about 85% of the casing was gone and nine of the ten frankfurters were free of the casing. In this respect, enough of the casing was metabolized to permit the remaining casing to slip from the frankfurter and settle in the beaker. At 2.0 hours about 95% of the casing was solubilized. At 3.5 hours substantially all the casing was gone and at 5.0 hours no casing was seen. In the blend solution about 95% of the casing was solubilized after 2.0 hours.
The same general trend, albeit somewhat slower, was observed with the frankfurters stuffed into a derivitized cellulose casing and the XL/CL blend appeared to be slightly more effective based on visual observations, than the XL alone. Here, after 1.5 hours about 60% of the derivitized casing was solubilized by the XL/CL blend and some of the frankfurters had slipped from the casing. After 3.5 hours in the XL/CL blend solution and after 4.5 hours in the XL solution about 95% of the cellulose had been solubilized. No visible piece of the derivitized cellulose casing remained in either solution after 5.5 to 6 hours.
As compared with the previous tests using MULTIFLET™ CL alone, the XL enzyme containing a greater proportion of xylanase and the CL/XL blend both appeared to be the more effective agent to metabolize either types of cellulose casing.
Accordingly, it should be appreciated that the method of the present invention accomplishes its intended objects in providing an improved method for removing the cellulose casing from sausages such as frankfurters and the like. The use of an enzyme such as a cellulase or cellulase enzyme complex having xylanase activity can eliminate the need to apply special internal easy peeling coatings to the internal surface of the casing. It further eliminates the need for mechanical peelers and reduces utility costs by eliminating the use of steam in the peeling operation. The use of an enzyme or enzyme complex according to the present invention further eliminates the need to color the casing or provide the casing with stripes to highlight casing that may remain on the sausage after a mechanical peeling operation.
Although a preferred embodiment of the invention has been described in detail, it should be understood that modifications may be made without changing the spirit and scope of the invention as claimed. For example, since the enzyme is most active at a temperature of 50° C., it can be applied directly to the cellulose casing during the shirring of the casing. The enzyme then would remain relatively inactive until the casing is stuffed and processed to make the frankfurters. The moisture added by stuffing and an increase in temperature to 50° C. would activate the enzyme previously deposited on the cellulose casing to begin the metabolism of the casing. | The removal of a cellulosic casing from about a sausage stuffed and processed in the casing is accomplished by contacting the sausage with a cellulase or cellulase enzyme complex to metabolize the cellulosic casing on the sausage thereby producing a substantially casing-free sausage. | 0 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the invention
[0002] The present invention is generally directed to a system for temporarily shoring up an excavation site. More particularly the invention is directed to a reinforcing assembly for a corner connection used in a reinforcing arrangement that supports sheet piling in an excavation site.
[0003] 2. Description of the Prior Art
[0004] In a typical excavation site, workers are exposed to numerous hazards. The most common hazard is having the walls of the excavation site cave in on the workers, thus causing serious injury. Often due to soil conditions and wetness, the sides of a construction site will simply collapse. Water is a particularly dangerous hazard because it is so heavy and can destroy shoring, which has not been properly reinforced. Realizing this problem the government, at both the federal and state level, has set up specific requirements for all excavation sites to avoid the problem of cave-ins. For example the United States Department of Labor and, more specifically, the Occupational Safety and Health Administration (OSHA) requires that excavation sites be prepared with some type of shoring. Additionally many companies are now aware of the problems involved in a typical excavation site and have developed internal policies requiring shoring for any excavations they contract to have completed.
[0005] A good example of a typical excavation project is found in replacing underground storage tanks for a gasoline station. Typically, in such an operation, sheet piling is pounded into the ground in a generally rectangular configuration around the work site. The piling has to be driven extremely deeply into the ground and arranged to provide sufficient support against potential cave-ins. Typically the sheet piling has to be driven so deep that half its total height remains underground after the excavation has been completed. Use of such large amounts of material is quite expensive. After the sheet piling has been installed, the workmen then remove the dirt and fill material from within the rectangular shoring. During the work of removing the old storage tanks and replacing them with new storage tanks the shoring provides protection to the workmen against potential cave-ins. Once the storage tank replacement operation has been completed the shoring can either be completely removed or simply cut down We to a safe distance below ground and then left in place. Such a method of shoring an excavation site is extremely expensive.
[0006] Various solutions have been proposed in an attempt to cut down on the costs of shoring an excavation site. For example U.S. Pat. No. 5,154,541 discloses a modular earth support system. Specifically, the patent teaches using panels placed around an excavation site and interlocked with one another to form a generally rectangular shoring configuration. Once the panels are in place, reinforcing beams are placed behind the panels to ensure the weight and force of the dirt behind the panels does not cause the panels to fail. The main drawback of using such a system is that standard I-beams cannot be used. Rather, special beams that are cut exactly to size and additionally have a customized end configuration must be used. Such beams are particularly expensive; especially considering a large number of beams of varying sizes would have to be kept available for differently sized excavation sites.
[0007] Another proposed solution to reducing the high cost of shoring excavation sites is found in U.S. Pat. No. 4,685,837. This patent proposes using panels as shoring members in an excavation site and uses laterally extending braces to reinforce the panels. The braces are connected to one another by a bracket. Alternatively, the braces maybe connected to each other by means of a connection in which one brace has a pair of tabs welded thereto with each tab having an aperture formed therein. The apertures align with a hole in a second brace and a pin is placed though the apertures to complete the connection. In either case there is no provision to adjust the length of the braces and connectors and they must be custom made for each different sized excavation site.
[0008] Numerous other proposed solutions are available including using wooden shoring which is a custom made to a particular excavation site. Such shoring is used only at the designated site and then disposed of. As a result this approach is prohibitively expensive. Also wooden shoring is not as durable as its metal counterparts. Often water along with regular wear and tear at the construction site can destroy the shoring during the construction job.
[0009] Perhaps the best solution proposed so far is set forth in U.S. Pat. No. 6,416,259 which is incorporated herein by reference. In that patent a corner connection for temporary shoring is shown as being used in an excavation site. Specifically, the corner connection is used to secure I-beams together at corners within the excavation site. Typically, four I-beams are connected together to form a rectangular frame that is suspended within the excavation for bracing the shoring walls thereof. The corner connection itself comprises mating socket or connecting members that are placed over the ends of I-beams to be fastened together. Some portions of this prior patent are summarized below in the discussion of FIGS. 4 and 5 labeled “Prior Art”.
[0010] Turning now to FIG. 4 , there is illustrated a close-up view of a corner connection 11 located at the ends of two I-beams 20 , 21 , including two meeting connectors 29 , 30 . Each connector 29 , 30 has a similar overall shape. However, one type of connector 29 has a single tab 32 while the other type of connector 30 has a double tab 34 , 36 . A single tab type connector 29 shown in FIG. 4 includes a box-like main body portion 40 having an opening 45 therein for receiving an I-beam 21 . The box-like main body portion 40 comprises five major panels to form the open box shape. Opposing top 50 and bottom 51 panels are connected with opposing side panels 55 , 56 to form the square or rectangular opening 45 designed to receive the I-beam 21 . An end panel 57 also preferably square or rectangular in shape closes off one end of the box type main body 40 . These five pieces 50 , 51 , 55 , 56 , 57 are all made of heavy steel and are welded together. The end panel 57 and one of the side panels 56 have the single tab 32 welded thereto. The tab 32 is a flat plate like member that extends laterally from the box-like main body portion 40 of the connector 29 and has an aperture 60 formed therein. The tab 32 is made of a similar material as the panels of the box-like main body 40 . The tab 32 is preferably welded to the side 56 and end 57 panels.
[0011] A double tab type connector 30 shown in FIG. 4 includes a box-like main body portion 70 having an opening 75 therein for receiving an I-beam 20 . The box-like main body portion 70 comprises five major panels to form the open box shape. Opposing top 80 and bottom 81 panels are connected with opposing side panels 85 , 86 to form the square or rectangular opening 75 designed to receive the I-beam 20 . An end panel 87 also preferably square or rectangular in shape closes off one end of the box type main body 70 . These five pieces 80 , 81 , 85 , 86 , 87 are all made of heavy steel and are welded together. The end panel 87 and one of the side panels 86 have top and bottom tabs 34 , 36 welded thereto. The tabs 34 , 36 are flat members which extend laterally from the box-like main body portion 70 of the connector 30 and each have an aperture 90 , 91 formed therein. The tabs 34 , 36 are made of a similar material as the panels of the box-like main body 70 . The tabs 34 , 36 are preferably welded to the side 86 and end 87 panels. While other methods may be used to attach the tabs 34 , 36 it is important that the tabs 34 , 36 be able to withstand the tremendous hydraulic pressures which may be transmitted by sheet piling 219 (seen in FIG. 1 ) as it starts to buckle.
[0012] As can clearly be seen in FIG. 4 , connectors 29 , 30 may easily be joined together by placing the tab 32 of the single tab connector 29 within the two tabs 34 , 36 of the double tab connector 30 . Ideally, the single tab aperture 60 aligns with the apertures 90 , 91 formed in each of the two tabs 34 , 36 of the double tab connector 30 . A securing bolt or pin 100 is placed through the aligned apertures 60 , 90 , 91 in order to pivotably secure the connectors 29 , 30 together.
[0013] Turning now to FIG. 5 , there is shown a second preferred embodiment of the invention. Specifically, the box like connectors 29 , 30 of the first embodiment illustrated in FIG. 4 now are shown with modifications to support an added reinforcing member. Since the connectors 29 ′, 30 ′ shown in FIG. 5 are based on the connectors 29 , 30 shown in FIG. 4 only a discussion of the modifications will be provided here.
[0014] Essentially each box type connector 29 ′, 30 ′ has a box-like main body 40 ′, 70 ′ that has been lengthened along with its corresponding panels 50 ′, 51 ′, 55 ′, 56 ′, 80 ′, 81 ′, 85 ′, 86 ′ to provide room to support a pair of extra tabs 101 , 102 , 103 , 104 each tab has an aperture (only two shown) 106 , 108 formed therein. A reinforcing bar 120 having a tab 130 , 131 located at each end is provided to reinforce the two box type connectors 29 ′, 30 ′. The tabs 130 , 131 located at the end of reinforcing bar 120 each have an aperture (not shown) located therein which will cooperate and align with the apertures 106 , 108 , formed in the extra tabs 101 , 102 , 103 , 104 of each box type connector 29 ′, 30 ′. A pin 100 may then be placed in the respective apertures once they are in proper alignment to hold the reinforcing bar 120 in place.
[0015] However even with this reinforcing bar 120 in place the maximum permissible load may be insufficient and the expense of using heavier materials is always a factor.
[0016] Based on the above, therefore there exists a need in the prior art of excavation shoring to provide a system wherein shoring can be provided at an excavation site in an inexpensive and reusable manner that does not suffer the disadvantages of the prior art discussed above. More specifically there exists in the art a need to provide a connector for interconnecting various beams used to reinforce shoring in a manner which may allow much greater loading than previously has been available but still uses the same parts as used in previous shoring systems.
SUMMARY OF THE INVENTION
[0017] Specifically, a corner connection used to secure I-beams together at corners within the excavation site is provided with a reinforcing assembly that allows for greater loads. Typically, four I-beams are connected together to form a rectangular frame that is suspended within the excavation for bracing the shoring walls thereof however; any polygonal shape may be used. The corner connection itself comprises mating socket or connecting members that are placed over the ends of I-beams to be fastened together.
[0018] One of the connecting members includes an outwardly extended tab while the other includes a pair of outwardly extended tabs. The first outwardly extending tab fits between the two extending tabs of the corresponding connecting member. All of the tabs are provided with apertures that are placed in alignment when the connection is made so that a bolt or pin can be passed through the apertures to secure the two connectors together. An additional set of tabs is provided on the connecting members that is also provided with apertures. A reinforcing assembly is provided and includes a reinforcing bar with tabs. A first spacer bar is attached to the reinforcing bar and one connecting member and a second spacer bar is attached to the reinforcing bar and an adjacent connecting member. The spacer bars, the reinforcing bar and the connection members are all connected with tab/pin connections. Advantageously the reinforcing assembly can use the existing second set of tabs located on the prior art connectors.
[0019] The socket members also include a large eyelet for receiving a chain or other elongated supporting member that is typically used to suspend the resulting I-beam frame at a desired height within the shoring walls.
[0020] Additional objects, features and advantages of the present invention will more readily be apparent from the following description of the preferred embodiment thereof, when taken in connection with the drawings wherein like reference numerals refer to correspond parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a prospective view of a corner connection, a reinforcing assembly and associated shoring beams for temporary shoring according to a first preferred embodiment of the invention as it would be seen in use in a typical excavation site;
[0022] FIG. 2 is a close-up perspective view of a corner connection including two corner connectors and a reinforcing assembly shown in their engaged condition connecting two shoring beams according to the first preferred embodiment of the invention;
[0023] FIG. 3 is an exploded view of the assembly shown in FIG. 2 ;
[0024] FIG. 4 is a prospective view of a corner connection including two corner connectors shown in their engaged condition according to the prior art and;
[0025] FIG. 5 is a plan view of a corner connection including two corner connectors and a reinforcing bar shown in their engaged condition according the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Referring now to FIG. 1 there is shown a typical excavation site 205 with an excavation hole 206 incorporating corner connections 211 - 214 for temporary shoring 218 according to a preferred embodiment of the invention. The temporary shoring 218 actually comprises three major elements: interlocking sheet piling 219 , reinforcing I-beams or shoring beams 220 - 223 and corner connections 211 - 214 , each connection including two connectors for the I-beams 220 - 223 . Although shown here as I-beams, beams of different shapes could be used so long as the connector and beam have mating shapes. For example, round, L-shaped and U-shaped beams could be used, as could a beam of almost any cross section. Interlocking sheet piling 219 is shown placed along the walls of the excavation hole 206 . Such interlocking sheet piling 219 , which in the embodiment shown is formed by interconnecting two types of side wall panels and corner panels (not separately labeled), is usually driven into the ground prior to any digging. Typically a driving machine 225 , which is essentially a pile driver, is used to drive each section of piling 219 to a desired depth within the ground. As mentioned above, typically such sheet piling 219 was driven two to three times the depth of the excavated hole 206 . In this preferred embodiment however, because of the I-beams 220 - 223 and the corner connections 211 - 214 , the sheet piling 219 need only be driven slightly deeper than the desired depth of the excavation hole 206 . In either case the sheet piling 219 is driven into the ground one panel at a time each panel becoming an upstanding wall portion.
[0027] The panels of piling 219 have interlocking edges and thus can provide support for each other once they are in place. Also the panels 219 are formed in an undulating pattern for added strength. Typically such panels 219 are made of relatively thick and expensive sheet metal. It is important to note that using large quantities of such a sheet metal is extremely expensive. Furthermore, using prior shoring methods, the sheet metal was often left at the excavation site 205 at the conclusion of the construction job. As will be discussed more fully below, with the subject method, the amount of sheet piling 219 used is not only reduced, but less sheet piling 219 is required initially because the sheet piling 219 only has to extend as deep as the excavation hole 206 .
[0028] A reinforcing structure 226 is provided behind the interlocking sheet piling 219 . The reinforcing structure 226 includes the set of I-beams 220 - 223 that interact with the set of corner connections 211 - 214 . Such a structure 226 is needed in order to prevent the sheet piling 219 from buckling under the weight of the earth surrounding the sheet piling 219 . This is particularly true when the earth is wet or particularly loose. The corner connections 211 - 214 are designed to receive the ends of the I-beams 220 - 223 to form a rectangular structure. While a rectangular shape is shown here and is probably the most common configuration used it should be kept in mind that any polygonal configuration of three or more sides could be used and not depart from the spirit of the invention.
[0029] Under normal conditions the reinforcing structure 226 would simply be suspended by a chain or other mechanism (not shown) at a desired height within the excavation hole 206 . If however, the sheet piling 219 starts to buckle under the weight of wet earth it will immediately engage with the reinforcing structure 226 . As pressure is placed on the I-beams 220 - 223 and corner connections 211 - 214 they will only give a small distance before applying an enormous normal force that will stop the sheet piling 219 from any further buckling.
[0030] Turning now to FIG. 2 , there is illustrated a close-up view of a corner connection 211 including two meeting connectors 229 , 230 and the ends of two I-beams 220 , 221 . Each connector 229 , 230 has a similar overall shape. However, one type of connector 229 has a single tab 232 while the other type of connector 230 has a double tab 234 , 236 . A single tab type connector 229 shown in FIG. 2 includes a box-like main body portion 240 having an opening 245 therein for receiving an I-beam 221 . The box-like main body portion 240 comprises five major panels to form the open box shape. Opposing top 250 and bottom 251 panels are connected with opposing side panels 255 , 256 to form the square or rectangular opening 245 designed to receive the I-beam 221 . An end panel 257 also preferably square or rectangular in shape closes off one end of the box type main body 240 . These five pieces 250 , 251 , 255 , 256 , 257 are all made of heavy steel and are welded together. The end panel 257 and one of the side panels 256 have the single tab 232 welded thereto. The tab 232 is a flat plate-like member that extends laterally from the box-like main body portion 240 of the connector 229 and has an aperture 260 formed therein. The tab 232 is made of a similar material as the panels of the box-like main body 240 . The tab 232 is preferably welded to the side 256 and end 257 panels. While other methods may be used to attach the tab 232 , it is important that the tab 232 be able to withstand the tremendous hydraulic pressures that may be transmitted by the sheet piling 219 as it starts to buckle.
[0031] Optionally a gusset 262 is formed between the side panel 256 and the tab 232 for added strength. An additional gusset (not shown) may be formed between the tab 232 and the end panel 257 . Preferably an eyelet 269 is formed on the top panel 250 . The eyelet 269 is designed to receive a chain or other elongated supporting member (not shown) used to support the I-beams 220 - 223 and corner connections 211 - 214 at a desired height within the excavation hole 206 . The eyelet 269 is completely optional as the chain could simply be placed around one of the I-beams 220 - 223 to provide support.
[0032] A double tab type connector 230 shown in FIG. 2 includes a box-like main body portion 270 having an opening 275 therein for receiving an I-beam 220 . The box-like main body portion 270 comprises five major panels to form the open box shape. Opposing top 280 and bottom 281 panels are connected with opposing side panels 285 , 286 to form the square or rectangular opening 275 designed to receive the I-beam 220 . An end panel 287 also preferably square or rectangular in shape closes off one end of the box type main body 270 . These five pieces 280 , 281 , 285 , 286 , 287 are all made of heavy steel and are welded together. The end panel 287 and one of the side panels 286 have top and bottom tabs 234 , 236 welded thereto. The tabs 234 , 236 are flat members that extend laterally from the box-like main body portion 270 of the connector 230 and each have an aperture 290 , 291 formed therein. The tabs 234 , 236 are made of a similar material as the panels of the box-like main body 270 . The tabs 234 , 236 are preferably welded to the side 286 and end 287 panels. While other methods may be used to attach the tabs 234 , 236 it is important that the tabs 234 , 236 be able to withstand the tremendous hydraulic pressures which may be transmitted by the sheet piling 219 as it starts to buckle.
[0033] Optionally a gusset 292 is formed between the side panel 286 and the top tab 234 for added strength. Webs (not shown) may be formed between the two tabs 234 , 236 in order to further increase their strength. An additional gusset (not shown) may be formed between the top tab 234 and the end panel 287 . Preferably an eyelet 295 is formed on the top panel 280 . The eyelet 295 is designed to receive a chain or other elongated supporting member (not shown) used to support the I-beams 220 - 223 and corner connections 211 - 214 at a desired height with the excavation site 205 . The eyelet 295 is completely optional as the chain could simply be placed around the I-beams 220 - 223 to provide support.
[0034] As can clearly be seen in FIG. 2 , connectors 229 , 230 may easily be joined together by placing the tab 232 of the single tab connector 229 within the two tabs 234 , 236 of the double tab connector 230 . Ideally, the single tab aperture 260 aligns with the apertures 290 , 291 formed in each of the two tabs 234 , 236 of the double tab connector 230 . A securing bolt or pin 300 is placed through the aligned apertures 260 , 290 , 291 in order to pivotably secure the connectors 229 , 230 together. The bolt or pin 300 previously supported all the forces transmitted between the two connected I-beams 220 , 221 and was subject to failure. However as discussed more fully below, the temporary shoring 218 has been modified with an improved reinforcing assembly 300 330 .
[0035] As can best be seen in FIG. 3 each box type connector 229 , 230 also supports a pair of extra tabs 301 , 302 , 303 , 304 and each tab has an aperture 306 , 307 , 308 , 309 formed therein. While the box connectors 229 , 230 are shown with pairs of extra tabs 301 , 302 , 303 , 304 only a single extra tab 302 , 304 on each connector 229 , 230 is required. The box type connectors 229 , 230 described so far are known in the art and are substantially identical to the box type connectors 29 ′ 30 ′ described above with reference to FIG. 5 .
[0036] The reinforcing assembly 330 includes a reinforcing bar 320 , a first spacer bar 322 attached to the reinforcing bar 320 and the first shoring beam connector 229 and a second spacer bar 324 attached to the reinforcing bar 320 and the second shoring beam connector 230 . The reinforcing bar 320 is formed of a standard I-beam that has had its ends cut at 45 degrees so as to form the overall temporary shoring 218 into a square configuration. As mentioned above other shapes and angles could be used. The reinforcing bar 320 will preferably be 8 feet or 12 feet long but other sizes may be used as desired. The spacer bars 322 , 324 are simply rectangular flat pieces of steel. The spacer bars must be sized based on the length of the reinforcing bar 320 and the angle of the corner connection. As such this length is set by the geometry of the temporary shoring 218 .
[0037] A first fastening assembly 335 includes the first tab 301 that extends laterally from the main body portion 240 of the first shoring connector 229 . The first tab 301 has an aperture 306 located therein adapted to receive a first connecting pin 336 . Optionally the first fastening assembly may also include the second tab 302 having aperture 307 aligned with aperture 306 and adapted to receive the first connecting pin 336 . A second fastening assembly 340 includes the first tab 303 extending laterally from said main body portion 270 of the second shoring beam connector 230 , and has aperture 309 located therein adapted to receive a second connecting pin 346 . Optionally the second fastening assembly 340 may also include a second tab 304 having an aperture 309 aligned with the aperture 308 and adapted to receive second connecting the pin 346 .
[0038] The reinforcing bar 320 further comprises a first tab 350 with an aperture 351 adapted to receive a third connecting pin 352 located at a first end 353 and a second tab 354 with an aperture 355 adapted to receive a fourth pin 356 located at a second end 357 . Optionally third and fourth tabs 358 , 359 may be added to the reinforcing bar 320 and be aligned with first and second tabs 350 , 354 respectively.
[0039] The first spacer bar 322 further comprises an end 360 with an aperture 361 located therein adapted to receive the first connecting pin 336 , a second end 363 with an aperture 364 located therein is adapted to receive the third pin 352 . When the optional tabs 302 , 358 of the first corner connector 229 and the reinforcing bar 320 are used, the ends 360 , 363 of the spacer bar 332 will fit between the tabs 301 , 302 of the first corner connector 229 and the tabs 350 , 358 of the reinforcing bar 320 .
[0040] The second spacer bar 324 further comprises a first end 370 with an aperture 371 located therein adapted to receive the second connecting pin 346 . A second end 373 with an aperture 374 located therein is adapted to receive the fourth pin 356 . When the optional tabs 304 , 359 of the second corner connector 230 and the reinforcing bar 320 are used the respective ends 370 , 373 of the spacer bar 324 will fit between the tabs 303 , 304 of the second corner connector 230 and the tabs 354 , 359 of the reinforcing bar 320 .
[0041] The reinforcing bar 320 has a hook 380 , 382 attached to each end 384 , 386 and each said hook 380 , 382 is adapted to be connected to a respective shoring beam 221 , 220 . The hooks 380 , 382 are formed of a main plate 390 , 391 welded to each end 384 , 386 of the reinforcing bar 320 and an additional two smaller plates 394 , 395 , 396 , 397 are welded to the main plates 390 , 391 to form a hook configuration. The hooks 380 , 382 mate with the top web of the respective I-beam shaped shoring beams 221 , 220 . Additional lower hooks 398 , 399 may be mounted to the main plates 390 , 391 but they are completely optional because the weight of the reinforcing bar 320 is sufficient to keep it in place.
[0042] In operation, typically the entire temporary shoring assembly 218 arrives on a truck. Initially the I-beams 220 - 223 are arranged in a rectangular or other polygonal shape around the perspective excavation site. Next the connectors 229 , 230 such as shown in FIG. 2 are placed on the ends of the I-beams 220 - 223 forming corner connections 211 - 214 . It is important to note that the connectors 229 , 230 may simply be slipped onto the ends of the I-beams 220 - 223 and that they do not need to be welded thereto. Essentially the main body portion 240 of the connector 229 is adapted to slidably receive the end of an I-beam 221 until it hits an abutment such as the end wall 257 . Of course, any abutment will do so long as it transfers force from the I-beam 221 to the connector 229 . As such, the connections 211 - 214 and I-beams 220 - 223 may be easily assembled on excavation site 205 . Next the apertures 260 , 290 , 291 in the tabs 232 , 234 , 236 of each single and double tab connector 229 , 230 are aligned and a pin 300 is placed therethrough. After the connections 211 - 214 and beams 220 - 223 are in place, the reinforcing assembly 330 may be added.
[0043] First the reinforcing bar 320 is placed on the shoring beams 221 , 220 so that the hooks 380 , 382 seat on the top web (not separately labeled) of each shoring beam 221 , 220 . Next the spacer bars 322 , 324 are placed so that the apertures 361 , 364 , 371 , 374 on the first and second ends 360 , 363 ; 370 , 373 of each bar 322 , 324 align with the appropriate apertures 306 - 309 , 351 , 355 , of the corner connectors 229 , 230 and reinforcing bar 320 . At this point the optional lower hooks 398 , 399 may be installed. The reinforcing structure 226 formed of the I-beams 220 - 223 and corner connections 211 - 214 now defines the edge of the excavation site 205 . The sheet piling 219 is driven into the ground around the reinforcing structure 226 .
[0044] Previously, the sheet piling 219 would have to be driven 2 ft. into the ground for every 1 ft. deep into the ground the excavation site 205 would extend. The cost of using so much sheet piling 219 is extremely expensive. With this new invention the sheet piling 219 need only extend slightly below the bottom of the excavation site 205 .
[0045] Once the sheet piling 219 is in place, the dirt and other material within the excavation site's perimeter is then removed. The reinforcing structure 226 is then lowered to an appropriate height. The reinforcing structure 226 is held at that height by chains that extend to the eyelet on each box connector. It should be noted that the reinforcing structure 226 would not actually be under load until and if the sheet piling 219 starts to buckle under the load of dirt or water located behind a sheet piling 219 . If the sheet piling 219 starts to buckle the corner connections 211 - 214 will take that load and be forced tighter unto their respective I-beams 220 - 223 . Once any tolerance between the I-beams 220 - 223 and corner connections 211 - 214 is taken up the reinforcing structure 226 will then prevent any further movement of the sheet piling 219 and also prevent a cave in. When pressure is applied to the main I-beams 220 - 223 from the walls of the excavation hole 205 as they try to collapse the spacer bars 322 , 324 keep the reinforcing bar 320 in place and stop it from moving away from the corner connection 211 . The reinforcing bar 320 then takes most of the load, much more of a load than could be handled by the corner connection 211 on its own. Workers can then move about the excavation site 205 and safely perform whatever task is necessary. For example, the workers could remove old storage tanks (not shown) that may need removing and replace them with a new set of storage tanks (not shown). Additionally, other structures may be formed within the excavation site 205 . For example a slab of concrete may be poured at the bottom of the excavation site 205 to aid in supporting storage tanks. Additionally, gravel or other fill material may be placed around the tanks as is needed. All the while, the workers will be safe from any potential cave in.
[0046] Once the excavation site 205 is ready to be refilled, typically a corner sheet of piling 219 is removed so as to enable the workers to remove the corner connections 211 - 214 . Once one set of corner connectors is removed, the rest of the reinforcing structure 226 can easily be removed from the excavation site 205 and used again. One of the great benefits of the instant invention is that a much greater load can be supported by the overall temporary shoring 218 . Additionally, with the use of the reinforcing assembly 330 even larger holes may be shored. Indeed holes with sides of up to 60 feet per side may be shored which much greater than can be shored without the reinforcement assembly 330 .
[0047] Although described with respect to preferred embodiments of the invention, it should be understood that various changes and/or modifications could be made to the invention without departing from the spirit thereof. Therefore, the specific embodiments disclosed herein are to be considered illustrative and not restrictive. Instead, the invention is only intended to be limited by the scope of the following claims. | A corner connection used to secure I-beams together at corners within the excavation site is provided with a reinforcing assembly that allows for greater loads. Typically, four I-beams are connected together to form a rectangular frame that is suspended within the excavation for bracing the shoring walls thereof, however, any polygonal shape may be used. The corner connection itself comprises mating socket or connecting members that are placed over the ends of I-beams to be fastened together. One of the connecting members includes an outwardly extended tab while the other includes a pair of outwardly extended tabs. The first outwardly extending tab fits between the two extending tabs of the corresponding connecting member. All of the tabs are provided with apertures that are placed in alignment when the connection is made so that a bolt or pin can be passed through the apertures to secure the two connectors together. An additional set of tabs is provided on the connecting members that is also provide with apertures. A reinforcing assembly is provided and includes a reinforcing bar with tabs. A first spacer bar is attached to the reinforcing bar and one connecting member and a second spacer bar is attached to the reinforcing bar and an adjacent connecting member. The spacer bars, the reinforcing bar and the connection members are all connected with tab/pin connections. Advantageously the reinforcing assembly can use the existing second set of tabs located on the prior art connectors. Such an arrangement provides much greater support for the sidewalls of the excavation site. | 4 |
The present invention relates to systems and methods for measurement of surface profile, and more particularly to a system and method for measuring the profile of a vehicle travel surface such as a road or runway. Yet more specifically, the invention relates to improvements in the system disclosed and claimed in U.S. Pat. No. 3,266,302.
The term "road" is used herein in a generic sense to include highways, streets and the like commonly travelled by automotive vehicles, runways and other surfaces used by aircraft for take-off and landing, railways, and any other type of surface over which a vehicle may travel.
BACKGROUND OF THE INVENTION
In accordance with the teachings of U.S. Pat. No. 3,266,302, a measurement vehicle is propelled over a road surface, and surface profile (W) is measured as a conjoint function of displacement of the vehicle suspension system (W-Y) and the twice-integrated output (Y) of an accelerometer carried by the vehicle. The disclosed system is described as effecting profile measurement with respect to a plane of reference, defined by inertia of the vehicle, over a total frequency range of road surface undulations determined at lower frequencies by accelerometer response characteristics and at higher frequencies by the vehicle suspension displacement transducer. However, the signal/noise response capabilities of the accelerometer at lower frequencies and any steady-state offset in the electrical output of both transducers, coupled with the described double integration, limit the capabilities of the system to the extent disclosed in the referenced patent.
To overcome the low frequency response difficulties which inhere in the accelerometer/double-integration technique, it was proposed in Spangler et al, "A Method of Measuring Road Profile", GMR-452, General Motors Corp. (1964) to subject the accelerometer output to a time domain highpass filter for attenuating the low frequency response prior to time domain double integration. However, since the spatial frequency content of the road profile varies in proportion to vehicle velocity, the provision of the highpass time domain filter causes the measured profile to vary as a function of vehicle speed. This problem was alleviated to some extent by providing a highpass filter with a step-wise variable natural or cutoff frequency thereby to accommodate step-wise differing but constant vehicle speed.
A further improvement which is prior art to the present invention implemented time domain digital processing techniques in place of, but exactly analogous to, the analog time domain processing techniques proposed in the above-referenced patent and GMR paper. This improvement embodied the capacity for user-input of desired frequency (or wavelength) measuring capability and contemplated vehicle speed. A corresponding highpass filter natural frequency was computed and applied to the accelerometer output in time domain computation of road profile. Although the technique so implemented effectively replaces the earlier step-wise selectable filter with a continuously variable filter, it was still necessary to maintain a constant vehicle velocity during the measurement process.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and system of the described type which provide a profile output having a constant spatial frequency content independent of vehicle speed and/or variations in vehicle speed.
Another and more specific object of the invention is to provide a profile measurement method of the type described which is readily adaptable for either analog or digital implementation, and to provide analog and digital apparatus implementing such method.
A more general object of the invention is to provide an improved and reliable method and apparatus for measuring surface profile, with particular adaptation to road surface profile, which remedy some or all of the aforementioned deficiencies and shortcomings of the prior art.
The foregoing and other objects are accomplished in accordance with the invention by providing a system and method which measure road profile in the spatial domain rather than the time domain. Specifically, a transducer is responsive to rotation of a road-contacting wheel for initiating a road profile sample measurement at preselected distance intervals ds along the road surface. Profile W is then measured in accordance with the equation
W=(W-Y)+∫∫(Y/V.sup.2) ds ds, (1)
where the quantity (W-Y) is a measure of displacement of the "sprung inertial vehicle" mass relative to the road surface, Y is acceleration of the "vehicle sprung inertial" mass normal to the road surface and V is vehicle velocity in the direction of travel. The quantity (Y/V 2 ) is a time-indepedent measure of spatial acceleration of the sprung inertial mass of the measurement vehicle. Thus, the units of all quantities in equation (1) are time-independent units of distance. Velocity V may be measured at each distance interval using a suitable transducer, or may be determined by the equation
V=(ds/dt) (2)
where dt is the time required to travel the distance interval ds.
Spatial acceleration given by the expression (Y/V 2 ) is subjected to a highpass filtering operation to attenuate any low frequency and steady-state components of the transducer signals. However, the filter cutoff frequency, which is in time-independent spatial frequency units of radians per unit length, remains constant during the measurement cycle (following initialization) and produces a road profile measurement having the desired frequency (wavelength) information content regardless of vehicle velocity and/or changes in vehicle velocity.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:
FIG. 1 is a schematic diagram of a vehicle equipped with a road profilometer in accordance with the invention;
FIG. 2 is a functional block diagram of an analog embodiment of the road profile computer shown in block form in FIG. 1;
FIG. 3 is a flow chart of a digital embodiment of the road profile computer of FIG. 1 comprising a programmed digital computer;
FIG. 4 is a functional block diagram of a digital embodiment of the road profile computer of FIG. 1 corresponding to FIG. 3 but comprising discrete electronic hardware;
FIG. 5 is a fragmentary flow chart of a modification to FIG. 3 between lines A--A and B--B; and
FIG. 6 is a fragmentary functional block diagram of a corresponding modification of FIG. 4.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 illustrates a vehicle 10 equipped with a road profile measurement apparatus or profilometer 12 in accordance with the invention for measuring road profile W as a distance from an imaginary plane 14 defined by the inertia element of an accelerometer 20 mounted on the sprung vehicle mass. Apparatus 12 includes a distance measuring device or transducer 16 mounted with the accelerometer 20 on the sprung mass of vehicle 10 for measuring the distance (W-Y) to the actual road surface 18, which distance varies as a function of the vehicle suspension system (not shown) as vehicle 10 travels over the road surface. Device 16 may take the form of a road following wheel and a variable resistor as shown in the above-referenced patent mounted on a separate towed vehicle. Ultrasonic and other non-contact transducers have also been proposed and may be mounted on vehicle 10 per se.
The accelerometer 20 mounted with displacement transducer 16 and responsive to acceleration of the sprung mass of the measurement vehicle in a direction perpendicular to inertial reference plane 14 to provide the acceleration signal Y. Accelerometer 20 and distance transducer 16 direct their respective outputs to a road profile computer indicated generally at 22. The above-referenced patent and GMR publication disclose prior art embodiments of computer 22 as previously discussed, and also discuss in detail background theory and operation of road profilometry in general. The patent and publication are incorporated herein by reference for such background discussions. FIGS. 2-6 to be discussed in detail hereinafter illustrate various preferred embodiments of computer 22 in accordance with the present invention. The output W F of computer 22, which indicates profile W suitably spatially filtered to highlight spatial frequency (wavelength) content of interest, is fed to a data storage device 24, which may comprise a strip chart recorder, magnetic tape recorder, etc.
In accordance with the present invention, computer 22 operates exclusively in the spatial domain. In the preferred embodiment herein disclosed, such spatial domain operation is carried out under control of a train of distance pulses S received from a road travel distance measuring transducer 26. Transducer 26 may be suitably mounted to one of the vehicle wheels as shown, or to a separate "fifth wheel", so as to provide a pulse S of fixed time duration t in response to travel of the vehicle over a predetermined fixed distance ds. Transducer 26 may comprise electro-optical couplers responsive to a suitably apertured disc for providing pulse S of duration t at a rate (1/ds) of twenty per foot (approximately 1.5 pulses per centimeter) of travel, for example. In this example, therefore, each pulse S indicates a distance ds of 0.05 feet (1.524 cm). Time interval dt between successive pulses S will vary with vehicle speed.
FIG. 2 is a functional block diagram of an analog embodiment of computer 22 for providing the filtered output W F as a function of inputs S, Y and (W-Y) previously discussed. An electronic switch 30 is responsive to transducer 26 for connecting a voltage source to an integrator 32, the frequency of such connections, and therefore the output V of integrator 32, being a function of vehicle velocity. Math module 34 receives the accelerometer signal Y and velocity signal V from integrator 32, and provides an output A as a function of the quantity (Y/V 2 ). This quantity, which is an expression of acceleration in the spatial domain, is fed through an electronic switch 36 to an integrator 38. The output I of integrator 38 is fed to one input of a summing amplifier 40.
The output G of amplifier 40 is fed through an electronic switch 42 to an integrator 44 which has an output P connected to one input of a summing amplifier 46. The output Y1 of amplifier 46, which may be visualized in FIG. 1 as corresponding to the total distance from devices 16 and 20 to the inertial reference plane 14, is fed to a summing amplifier 48. Amplifier 48 receives a second input (W-Y) from device 16, and provides at its output the profile measurement W F as a function of the sum (W-Y)+Y1.
The highpass spatial domain analog filter of the embodiment of FIG. 2 is illustrated by the general reference numeral 50. The output W F of amplifier 48 is fed back through the electronic switch 52 to an integrator 54 which has a gain factor T3. The output D of integrator 54 is fed through an electronic switch 56 to an integrator 58, which has an output E fed to a second input of summing amplifier 40. The output W F of amplifier 48 is also fed through an electronic switch 60 to an integrator 62 having gain factor T2, and which has an output F fed to a third input of amplifier 40. The output W F of amplifier 48 is also fed through an electronic switch 64 and an integrator 66 with gain factor T1, the latter having an output H connected to the second input of summing amplifier 46.
The gains of integrators 66, 62, 54 correspond to the spatial highpass filter constants T1, T2, T3, which are respectively given by the following equations:
T1=2·(2π/L) (3)
T2=2·(2π/L).sup.2 (4)
T3=(2π/L).sup.3 (5)
where L (FIG. 1) is the maximum desired profile measurement wavelength preselected by an operator. (Means for presetting the gains of integrators 66, 62, 54 may be of conventional type and are not shown). The maximum desired wavelength L may be selected, for example, based upon the type of vehicle which will travel over the measured surface, normal traffic speed and passenger comfort. A maximum wavelength of 300 feet (91.4 meters) would be appropriate for medium size automobiles traveling 55 miles/hour (88.5 km/hr), while a wavelength of 550 feet (152.5 meters) may be appropriate for a commercial size passenger aircraft traveling at a runway speed of 100 miler/hr (160.9 kn/hr). Electronic switches 30, 36, 42, 52, 56, 60 and 64 are all identically responsive to pulses S from transducer 26 as previously described for connecting the corresponding input to the corresponding output for the fixed time duration t upon occurrence of each pulse S.
FIG. 3 illustrates the flow chart of a programmed digital computer embodiment of road profile computer 22 in FIG. 1. Letters and symbols used in FIG. 3, and in the succeeding drawings, correspond to letters and symbols previously discussed in connection with FIGS. 1 and 2. Likewise, to facilitate appreciation of the analogous relationship between FIGS. 2 and 3, and to forestall unnecessary repetition, stages in the flow chart of FIG. 3 which illustrate digital computation steps corresponding to analog stages in FIG. 2 are identified by corresponding reference numerals followed by the subscript a.
The process illustrated in FIG. 3 is characterized by an initialization technique illustrated by the stages 80 which allows spatial profile measurement on start-up independently of profiles previously measured, and by means of which the road profile measured during start-up has a spatial frequency content that exactly matches the spatial frequency filtering capability of the highpass digital filter 50a (corresponding to analog filter 50 in FIG. 2) at any given point in the initialization process. The initialization process ultimately sets the highpass spatial filter constants T1, T2 and T3 to correspond to the selected maximum desired measurement wavelength L, and reduces the effect of steady-state offset and low frequency noise in the output of accelerometer 20 and transducer 16 (FIG. 1) in the final output.
Immediately upon start-up, all variables I, H, F, D, E and P previously discussed are set at zero. L1, which in FIG. 3 is a variable which controls spatial frequency filter constants T1, T2 and T3, is initially set at zero and then incremented to ds at 81. Filter constants T1, T2 and T3 are computed accordingly at stages 82, 84, 86 per preceding equations (3) to (5). Upon occurrence of an S pulse from transducer 26 (FIG. 1), accelerometer output Y is sampled, distance measuring device output (W-Y) is sampled and time dt elapsed since the last S signal is read from a suitable internal clock. Velocity V is then determined as ds/dt, and digital computation of variables A, I, H, F, D, E, G, P, Y1 and W F proceed as shown and previously discussed. Note that inclusion of distance ds in computation of integrated variables I, H, F, D, E, and P is analogous in terms of operation in the spatial domain to inclusion of the S-operated electronic switches at the inputs of the analog integrators for computing the corresponding variables in FIG. 2.
Continuing the initialization process, i.e. until the variable L1 is equal to the user input L, L1 is incremented by the amount ds, and the filter constants T1, T2 and T3 are correspondingly recomputed on each pass--i.e. following each occurrence of an S pulse and computation of W F . When L1 is finally equal to L, the filter constants are at their final value, and W F is effectively computed upon occurrence of each S pulse from transducer 26 (FIG. 1). A complete listing of instructions for implementing the process of FIG. 3 is BASIC source code is as follows:
1.0..0.: ! START
11.0.: INPUT L
12.0.: I=.0.
13.0.: H=.0.
14.0.: F=.0.
15.0.: D=518
16.0.: E=.0.
17.0.: P=.0.
18.0.: L1=.0.
19.0.: L1=L1+S ! S=ds
2.0..0.: T1=2*(2*PI/L1)
21.0.: T2=2*(2*PI/L1) 2
22.0.: T3=(2*PI/L1) 3
23.0.: ! HAS DISTANCE ds BEEN TRAVELED?
24.0.: IF NO THEN 23.0.
25.0.: IF YES THEN 26.0.
26.0.: ! READ ACCELERATION (y2)
27.0.: ! READ DISPLACEMENT (W-Y)
28.0.: ! READ ELAPSED TIME (dt)
29.0.: V=S/T ! T=dt
3.0..0.: A=Y2/V 2
31.0.: I=I-A*S
32.0.: H=H+W1+T1*S ! W1=Wf
33.0.: F=F+W1+T2*S
34.0.: D=D+W1+T3*S
35.0.: E=E+D*S
36.0.: G=F+E+I
37.0.: P=P+G*S
38.0.: Y1=P+H
39.0.: W1=W-Y-Y1 ! W1=Wf
4.0..0.: IF L1=L THEN 23.0.
41.0.: GO TO 19.0.
42.0.: END
FIG. 4 is a functional block diagram of a discrete-circuit digital embodiment 70 of road profile computer 22 (FIG. 1). The elements and variable outputs are laid out in FIG. 4 in correspondence with corresponding analog elements and outputs in FIG. 2. The blocks of FIG. 4 are identified by reference numerals which find appropriate correspondence in FIGS. 2 and 3, followed by the letter b, including specifically the computation steps of FIG. 3 and highpass filter elements 50b of FIG. 4 which effect highpass spatial filtering in accordance with the invention. Operation of the embodiment of FIG. 4 will be evident from the foregoing discussion. It will be appreciated that the hardware for implementation of the previously-discussed initialization process 80 (FIG. 3) is not shown in FIG. 4. Hardware necessary for such implementation will be evident to the artisan.
FIGS. 5 and 6 illustrate respective modifications to FIGS. 3 and 4 wherein the highpass filtering operation is carried out in a "quasi spatial" domain in accordance with the invention utilizing vehicle velocity V and elapsed time dt between S pulses in the spatial domain computations. Stages or elements in FIGS. 5 and 6 which find correspondence in FIGS. 3 and 4 are indicated by respectively identical reference numerals followed by the letters c and d.
Specifically, FIG. 5 illustrates a modification to FIG. 3 between the lines A--A and B--B in the latter. Note that the terms dt·V, dt·V 2 and dt·V 3 replace the constant ds in computation of variables H, F and D respectively. This modification introduces temporal units (1/sec) in variables H, F and D, which are then removed by multiplication by time dt in computation of variables H, F, D, E and P. To implement the modification of FIG. 5 in the previous source code listing instructions 29.0. and 3.0..0. are eliminated, and instructions 31.0.-37.0. are replaced as follows:
31.0.: I=I-Y2*T ! T=dt
32.0.: H=H+W1*T1*T*V ! W1=Wf
33.0.: F=F+W1*T2*T*V 2
34.0.: D=D+W1*T3*T*V 3
35.0.: E=E+E*T
36.0.: G=F+E+I
37.0.: P=P+G*T
FIG. 6 illustrates a "quasi spatial" domain highpass filter 50d for use in place of filter 50b in FIG. 4. The modifications of FIGS. 5 and 6 are fully analogous to the pure spatial domain embodiments previously described, and are fully as effective in measuring road profile independently of vehicle speed and/or changes in vehicle speed in accordance with the invention. | Apparatus and method for use on a measurement vehicle to measure road surface profile independently of variations in vehicle velocity over the road surface. Transducers are mounted on the vehicle suspended mass for measuring distance (W-Y) to the road surface and acceleration Y normal to the road surface as the vehicle is propelled over the road surface. A third transducer is responsive to fixed increments ds of vehicle travel over the road surface. Surface profile is determined as a continuous function of the time-independent equation
W=(W-Y)+∫∫(Y/V.sup.2) ds ds,
ps where V is average vehicle velocity over each successive incremental distance ds. A spatial domain filter attenuates profile wavelength components in excess of a desired preselected maximum wavelength. | 1 |
TECHNICAL FIELD
This invention relates to a locking device for rectilinear or circular displacement jacks.
Jacks which are locked by rollers in an indifferent condition are already known, since these jacks are increasingly used in the automobile industry as well as for the setting of the seats of nautical and air vehicles.
However, the various solutions have not proved satisfactory because the lockage safety is insufficient.
BACKGROUND ART
Prior documents which can be mentioned are French Patent specifications No. 2,592,441 and No. 2,574,721.
But in both documents, smooth rollers are used for displacement and locking of the jacks, making it necessary to provide an extra safety device which is therefore costly and not completely safe.
DISCLOSURE OF THE INVENTION
The present invention remedies these disadvantages by providing a locking device for rectilinear or circular displacement mechanical jacks, the study of which has been more particularly addressed to providing a rectilinear and continuous displacement of the seating portion and a circular and continuous offset of the backing portion of vehicle seats, the movements of which can be obtained either manually or by an appropriate motorized system.
These embodiments are very simple and, at the same time, very safe since locking of the jack is perfect and resists transverse as well as frontal impacts. Also, the seats provided with these locking devices are not only very easily adjustable by the user but ensure a great safety since, should an accident occur, they absorb a considerable energy by being deformed, thereby protecting the passengers sitting on the seat, without any risk of an inadvertent unlatching.
According to the invention, the locking device for rectilinear or circular displacement jacks includes at least one rod normally locked by notched rollers mounted in notched V-shaped bearing plates having a vertical displacement which is created by rotation of a control cam controlled by one of a manual and motorized element, the control cam having studs rigidly connected thereto, and holding in position of the control cam being provided for a correct locking of the at least one rod under action of a spring placed on the studs, a positive return of the notched rollers and of the bearing plates being provided by two members in a shape of a two-pointed hat controlled by snugs connected to side faces of the cam.
According to another feature of the invention, the bearing plates are placed so as to provide an unlocking movement either in the upward direction or in the downward direction while being guided by an inner casing having a general shape of a trapezium and used as a support for the jack rod by a lower portion.
Various other features of the invention will become more apparent from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are shown by way of non limiting examples in the accompanying drawings, wherein:
FIG. 1 is a side elevation view of a first embodiment of the locking device for rectilinear displacement mechanical jacks provided with roller return springs;
FIG. 1a is an enlarged view corresponding to FIG. 1 and showing the position of various members of the locking device as well as the return coil spring of the control cam;
FIG. 1b is an enlarged partial view of FIG. 1, for a setting in position of the various parts of the locking device without the roller return springs;
FIG. 1c is an enlarged elevation view of the locking members shown in FIGS. 1, 1a and 1b;
FIG. 2 is a side elevation view of the locking device for circular displacement mechanical jacks adapted to a continuous adjustment of seat back;
FIG. 3 is a front elevation view corresponding to FIG. 2;
FIG. 4 is a side elevation view of an alternative embodiment of FIG. 2;
FIG. 5 is a side elevation view of a second embodiment of a rectilinear displacement mechanical jack provided with a locking device;
FIG. 6 is a side elevation view of a locking device for circular displacement mechanical jacks adapted to setting of a seat back;
FIG. 7 is an alternative embodiment of the device of FIG. 6;
FIG. 8 is front elevation view of a mechanical jack driven by a motive member for setting of a seat or of a slide by a motor;
FIG. 9 is a plan view corresponding to FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, FIG. 1 shows schematically the rod 1 of a jack which is rectilinear and the section of which is most often square.
The jack rod 1 carries, at its end 1a, a jack attachment system 2 made of a head through which extends a hole 3 for fixation of the rod 1 on a member rigidly connected for example to the mobile profile of a slide or on a rotation pin of a lever arm rigidly connected to a pivot of a seat back.
The jack rod 1 bears on a bottom 4 of an inner casing 5 having in elevation a shape of a trapezium, which casing 5 is covered by a lid casing 6 which is fixed to the inner casing 5 by turned over lugs 7 extending into pockets 8 formed in the inner casing 5.
A circular part 9 is provided on both sides of the casing 5, 6, which circular part 9 (see FIGS. 1 and 1a) has for its function a fixation of the casings 5, 6 either to the armature of a seat or to a point of another adjusting mechanism by forming the second fixation point of the rectilinear stroke jack for the embodiment of FIGS. 1, 1a, 1b, 1c.
These circular members 9 are placed in the vertical median axis X--X of the casings 5, 6. Slanting sides 8a, 8b of the casing 5 are used as guiding paths for two bearing plates 10, 11 in a shape of a cocked hat with a larger base which is machined in order to form each time two toothed ramps 12, 13 spaced apart by a recess 14. The ramps 12, 13 are each formed with a toothing adapted for cooperating with the notched rollers 15, 16 mounted on pins 17, 18 extending beyond the side faces of the rollers 15, 16. The pins 17, 18 are mounted in two members 19 having a shape of a two-pointed hat.
A cam 20 is placed between the two bearing plates 10, 11, and the movement of the cam 20 is controlled by a shaft 21. The assembly formed by the rollers 15, 16, bearing plates 10, 11, two-pointed hat-shaped member 19 and cam 20 is held within the casings 5, 6. Moreover, the shaft 21 carries a stud 22a, and the shaft 21 can be controlled in rotation either by a lever or by any other desired rotation means. Two protrusions 23 integral with the shaft 21 are placed in the central recess 20a of the member 19 which is in the shape of a two-pointed hat; the cam 20 being centered by means of bores formed in the casing 5, lid 6 and pin 21.
As may be understood from FIG. 1a, a coil spring 123 is fixed by one of its ends 123a on the stud 22a and by its other end 123b on a stud 22b rigidly connected to the lid casing 6.
Reference numerals 20b and 20c are the points of contact of the cam 20 with the side faces 10a, 11a of the bearing plates 10, 11.
The coil spring 123 is provided to hold the rollers 15, 16 in a pressed position via the bearing plates 10, 11 and cam 20 on the rectilinear and square rod 1.
Thus, when rotating the shaft 21 anticlockwise (see angle α in FIG. 1b), it is possible to cause a slight rotation of the cam 20, the steps 20b, 20c of which will move downwardly and thereby release the pressure which the cam exerts on the bearing plates 10, 11. Thus the toothings 12, 13 of the bearing plates 10, 11 get disengaged from the toothings of the rollers 15, 16 which were firmly bearing on the upper face of the jack rod 1, while locking this rod.
The jack rod 1 is therefore free and can be displaced in opposite directions shown by the double arrow F 1 (FIG. 1).
In some cases and in order to provide, when the cam 20 is retracted, an easy lifting of the notched rollers 15, 16, it is possible to additionally provide two curved springs 25 having substantially a shape of an Ω and centered about circular members 9 rigidly connected to both sides of the inner casing 5 and lid casing 6.
When the jack rod 1 has been placed in a correct position, the only thing to do is to rotate the shaft 21 clockwise so that the cam 20, via its steps 20b and 20c, will lock once more the bearing plates 10, 11 which will move downwardly, thereby locking the rollers 15, 16 on the upper face of the jack rod 1.
FIG. 1c shows the position of a roller (for example the roller 16) in the slanting and toothed ramps 12, 13. From the position of the members there appears an angle α 1 avoiding a tilting of the rollers (for example the roller 16) due to: i) the supports far from the roller teeth on the toothings 12, 13 provided in the bearing plates; and ii) the double support of the two upper teeth of the rollers on the rod 1. During displacement of this rod (straight or curved), there is produced a rotation of a tooth of the rollers in the corresponding staircase-shaped ramp, a compression of the assembly formed of the rod 1, roller 16, V-shaped members 11 and cam 20, then, by reaction of the inner casing 5 and lid casing 6 with the rod and the support of the cam 20 in the casing, which eliminates the horizontal clearance of the rod or the angular clearance if the rod is substituted by a curved part (FIG. 2 and following).
The fact that the peripheral toothings of the rollers 15, 16 cooperate with the toothings 12, 13 of the bearing plates 10, 11 provides a correct hold of these members with respect to one another and a positive meshing of the rollers 15, 16 with the upper face of the jack rod 1 by holding firmly this rod even in the case of lateral or frontal impacts of the vehicle composing the seats provided with this jack. There is thus obtained a greater safety.
FIG. 2 shows that the casing 30 has a curved bottom 31 on which bears on an arc-shaped rod 32 which is welded or otherly fixed on the lower portion of the armature 33 of the seat back. The casing 30 is attached to the vertical wing 35 of a base 36 fixed on the vehicle floor or on a sliding element, for example a slide. The locking members of the arc-shaped rod 32 are identical to those described in FIG. 1 and are therefore designated by the same references. But in this case, the return spring has not been shown, as it is not necessary to use it, since return of the rollers 15, 16 is effected by the two-pointed hat-shaped member 19 under action of the snug 23 acting on the cam 20 in the recess 20a. The rotary movement being counterclockwise, the grooved rollers 15, 16 immediately disengage themselves from the upper face of the arc shaped rod 32 due to the shape as such of the latter and thereby enable an easy rotation of the armature 33 about the pin 37 solid with the vertical wing 35 of the base 36.
There again, the safety of the device has been considerably increased since, when the cam 20 is in the locking position (position shown in FIG. 2) of the bearing plates 10, 11, the toothings of the rollers 15, 16 will extend sufficiently inside the face of the arc shaped rod 32 so as to ensure a perfect locking.
In both cases of FIGS. 1 and 2, the displacement is continuous and provides therefore a perfect setting either of the jack rod 1 or of the seat back in consideration, without spacing.
Such a setting is called a "0° setting" in case of the above jack used in a seat back articulation. Actually, one can obtain a displacement as small as possible so as to provide the user with a perfect comfort. It is also possible to obtain a displacement smaller than 1 mm in the case of a slide, which slide is then usually called a "0 mm displacement" slide.
FIG. 4 shows an embodiment substantially identical to that of FIG. 2, with the base 36 supporting the vertical wing 35 holding in position the casing 40 which has been reversed over 180°.
Actually, in this case, the bearing plates 10, 11 are placed in a position which is the reverse of the position previously occupied, and therefore the rollers 15, 16 will bear, when the device is unlocked, on the bottom of the recesses formed by the opposite slopes 12, 13 of each bearing plates 10, 11. There again, a return spring for the rollers 15, 16 is not necessary since, as soon as the cam 20 is unlocked, the bearing plates 10, 11 are returned by the two-pointed hat-shaped member 19 under action of the snug 23 acting on the cam 20 of the recess 20a. In fact, the movement is obtained by the pins 17, 18 of the rollers 15, 16 mounted in the two-pointed hat-shaped member 19. Thus, the rollers 15, 16 are free, and their toothings do not mesh with the lower face of the arc-shaped member 32 which is rigidly connected to the armature 33 of the seat back. When the cam 20 pivots in the positive direction, the bearing plates 10, 11 are lifted, and they push back the rollers 15, 16 which come in contact with the shaped member 32 and lock it against the bent over edge 45 of the casing 40. An unlatching of the device is effected in the reverse direction by rotation of the cam 20 driven by a control lever (not shown) or by any other suitable motive member.
In FIG. 5, the latching device for rectilinear rod 50 provided with the attachment head 51 is made of a single roller 52 cooperating with a single bearing plate 53, the bearing plate and this roller being grooved. The bearing plate 53 is subjected to action of the cam 20 carrying the protrusion 23 and, in this case, due to the reversed position of the bearing plate 53, it is necessary to use a casing 54 permitting a correct hold of the rectilinear rod 50 in the lid 55 and also to use a spring 56 having substantially the shape of an Ω, which is hooked at 56a inside the casing 55 and the other end 56b of which will bear on the pin 52a of the roller 52. Centering of the springs 56 is effected about the circular members 9 as in the case of FIG. 1. Operation of this latching device is identical to that previously described. Reference numeral 119 designates the member corresponding to the two-pointed hat-shaped member 19 of the previous mechanisms.
In FIG. 6, the device of FIG. 5 is used for positioning a seat back. The arc-shaped member 32 is identical to that shown in FIG. 2. Its operation is identical, and the members are therefore designated by the same references as in FIG. 5.
Finally, in FIG. 7, the device includes a single bearing plate 60 turned downwardly, but the operation of this device is identical to that of FIG. 2 and therefore the same references as those of the preceding figures are used again.
As may be seen in FIGS. 8 and 9, the rod 100 of the mechanical jack is, at its upper portion, provided with a rack 101 cooperating with a pinion 102 carried by a shaft 103 extending from a speed reducer 104 driven by a motor 105 which is of an electrical, pneumatic or the like type.
As regards the latching mechanism of the rod 100, there is no modification with respect to the arrangement shown and described in FIG. 1, and therefore these members are designated by the same references.
In the present case, when, with assistance of the lever 110, the rod 100 has been unlatched and when one wishes to have the rod 100 sliding frontwardly (arrow F 10 , FIG. 8), one presses the control 111 carried by the control knob 110a of the lever 110, which supplies the electric motor 105 through the reversing switch by rotating the pinion in direction of the arrow F 11 .
As soon as the position is reached, the control knob 111 is released, and the lever 110 is brought back to the latching position in order to lock the rod 100.
When one wishes to displace the rod 100 in the rear direction, the operation is identical as that just described, but by using the control knob 112. At that moment, the electric motor 105 drives the pinion 102 in direction of the arrow F 12 .
It is also possible, in a very safe manner, to substitute the lever 110 used for the unlatching and latching of the cam 20 by an electromagnet which, by unlocking this cam, unlatches the rod 100, then according to the supplying direction of the motor 105 of the stem 100, can move either in the front direction or in the rear direction. It is possible to use any suitable positioning control member so that the unlatching function is carried out before the motor control will supply the motor 105 with electric current. A memory electronic circuit can also be used.
As soon as the electric feed of the motor 105 is no more supplied, the feed of the electromagnet controlling the cam 20 is immediately cut off, and a spring member provided to this effect on the mobile armature of the electromagnet brings back the cam 20 in the locking position.
In the hereabove case, the motorization is an electrical motorization, but could also be a pneumatic or hydraulic motorization, the safety being thus increased since it is the return spring for the cam which locks the assembly when the electric current or the pneumatic or hydraulic feed is stopped for the natural reason of use or when there is a failure of the power feed. | The device comprises at least one rod normally locked by notched rollers mounted on pins and cooperating with at least one V-shaped bearing plate having toothed ramps, and the vertical displacement of which is made by rotation of a cam driven by a set of studs rigid with a circular member, with control means being further provided to drive this circular member. | 1 |
This is a division of application Ser. No. 07/190,310 filed May 4, 1988, U.S. Pat. No. 4,881,410, which is a division of application Ser. No. 07/057,884 filed June 1, 1987, now U.S. Pat. No. 4,815,472.
FIELD OF THE INVENTION
This invention relates in general to solid-state pressure sensors and methods of making them, and in particular to silicon pressure sensors having a diaphragm and supporting rim structure made from monocrystalline silicon wafers processed using etch-stop techniques.
BACKGROUND OF THE INVENTION
There are many applications requiring the accurate measurement of pressure, ranging from the monitoring of physiological parameters for medical research, to the precise control of fluids or gases, to measurement of low energy acoustical signals. Typical applications include industrial process monitoring, such as the monitoring of gas flow under partial vacuums in semiconductor processing facilities to the precise control of air/fuel ratios in automobiles. Typical medical applications include measurement of blood pressure in surgery and in intensive care, air pressure in respiratory diseases, intrauterine pressure in obstetrics, abdominal and urinary pressure for diagnosis of disorders, and the like. In some such applications, it is desirable to measure pressure with an extremely small sensor so as not to disturb the system being monitored. For example, cardiovascular catheterization has become a major and common diagnositic tool in dealing with the cardiovascular system. In angioplasty (balloon pumping) to treat occlusions in the coronary artery of the heart, there is presently no satisfactory means of judging the results on-line, that is, as treatment is being administered. Existing catheter-tip pressure sensor are single-point, not highly reliable, very expensive, and too large for use within the coronary artery. Also, they typically offer only low-level output signals which are very susceptible to noise and artifact.
Recent advances in silicon micromachining technology have allowed the development of a wide range of solid-state pressure sensors. Amongst the most useful, on account of their increased sensitivity, are capacitive pressure sensors. In the past few years the use of impurity-sensitive etch-stops and deposited diaphragm structures have resulted in precise, ultrathin diaphragms that have substantially broadened the range of practical structures which can be realized. In particular, a significant miniaturization of solid-state pressure sensors is now feasible. See for example, H. Guckel, et al, "Laser-Recrystallized Piezoresistive Micro-Diaphragm Sensor," Dig. Tech. Papers, IEEE Int. Conf. Solid-State Sensors and Actuators, pp. 182-185 (June 1985).; R. S. Hijab and R. S. Muller, "Micro-mechanical Thin-Film Cavity Structures for Low Pressure and Acoustic Transducer Applications," Dig. Tech. Papers, IEEE Int. Conf. Solid-State Sensors and Actuators, pp. 178-181 (June 1985).; and S. Sugiyama, et al, "Micro-Diaphragm Pressure Sensor," IEDM Tech. Dig., Dec. 1986. For a general review of factors affecting performance and down-sizing of pressure sensors, see H. L. Chau and K. D. Wise, "Scaling Limits in Batch-Fabricated Silicon Pressure Sensors," IEEE Trans. Electron Devices, Vol. ED-34, Apr. 1987. Thus, some techniques are now known for fabricating thin diaphragms essential for the ultraminiature sensors. However, improved fabrication techniques are needed along with improved sensor packaging and interface electronics in order to allow the sensors to be scaled downwardly while maintaining high performance and high yield. The most commonly used techniques for forming a diaphragm and supporting rim structure from a silicon wafer involve anisotropically etching a recess for the reference cavity of the transducer on the front side a silicon wafer, and selectively etching away 90% or more of the back of the silicon wafer in order to form a diaphragm of desired thickness. The diaphragm thickness is typically controlled using a boron buried layer or a p-n junction etch-stop. This back etching is done normally with preferential etchants which give a bevel having a wall angle of about 52 degrees. Due to the thickness of the silicon wafer, much lateral area around the diaphragm of the transducer is required, thus making it difficult to produce a small device. This use of lateral space is not productive, in that it is not a functional part of the sensor.
Many solid-state pressure transducers or sensors are made using a silicon wafer which is first preferably etched, and then electrostatically bonded to a glass substrate. In many such sensors, particularly those having larger diaphragms, the electrostatic bonding process requires the application of a very high applied field which tends to pull the diaphragm over the glass and weld it to the glass, thus resulting in an inoperable device. To avoid this problem, a field shield plate, which can be one of the electrodes of the capacitive transducer, is grounded during the sealing processing. However, grounding of individual capacitor plates during a batch process is very hard to arrange, and is more effectively done only when the transducers are bonded to a supporting piece of glass one at a time. However, to produce commercial quantities of transducers, it is highly desirable to be able to seal an entire wafer of silicon transducers to a glass plate at one time without having to ground the individual capacitor plates of the transducers.
Another problem with many techniques used for producing solid-state pressure sensors is that numerous processing steps are required, including a number of steps requiring critical alignment and masks and the like, thus increasing costs and reducing yield. Thus, it would desirable to provide for a simpler, more reliable process requiring fewer processing steps and fewer critical alignment steps. In this regard, it is noted that existing techniques for making ultraminiature pressure sensors are typically costly. For example for sensors approaching one millimeter in diameter, devices may cost as much as several hundred dollars each. Clearly, it would very desirable to provide a pressure sensor structure and method of making it which would permit the cost of producing such ultraminiature devices to be reduced considerably, perhaps by as much as an order of magnitude or more.
In light of the foregoing, it is a primary object of the present invention to provide an improved solid-state pressure sensor structure and method of making it which allows ultraminiature pressure sensors to be fabricated with fewer, less costly steps and greater yield. Other objects of the present invention include eliminating the large rim areas associated with existing pressure sensors having a diaphragm and rim structure made from bulk silicon, and eliminating the need to provide a field shield plate during the electrostatic bonding process.
Other objects of the present invention include providing a pressure sensor that is capable of multipoint operation, is addressable, and is compatible for use on a multisite catheter having only two leads, namely the electrical power supply leads. One more object is to provide such a sensor which allows on-chip temperature measurement for purposes of compensation. Yet another object is to provide such a catheter system suitable for medical uses such as cardiovascular catheterization. Additional objects of the invention include providing a transducer fabrication process that is fully batch in nature and does not require individual handling of small parts.
SUMMARY OF THE INVENTION
In light of the foregoing problems and to fulfill one or more of the foregoing objects, the present invention provides an ultraminiature capacitive pressure sensor having a silicon diaphragm and rim structure made with a simple double-diffusion process. This novel diaphragm and rim structure is part of a silicon transducer chip which is electrostatically bonded to a glass support plate prior to removal of all of the wafer except for the diaphragm and rim structure. The novel diaphragm and rim structure features a very small rim area, thus allowing the transducer to be constructed in ultraminiature form. Thus, capacitive pressure sensor of the present invention can be mounted, for example, in a 0.5 millimeter OD multisite cardiac catheter suitable for measuring blood pressure gradients inside the coronary artery of the heart. The silicon pressure transducer preferably includes supporting interface circuitry on a chip fastened to the same glass support plate as the diaphragm and rim structure.
According to one aspect of the invention, there is provided a method of making a pressure sensor having a diaphragm in rim structure including bulk silicon, which comprising the steps: (a) providing a silicon wafer; (b) forming at least one mesa upon the silicon wafer to be used as part of the rim structure of the pressure sensor; (c) impregnating a selected portion of the silicon wafer which includes the mesa with at least a first material which alters an etching characteristic of the first selected portion; (d) impregnating a second selected portion of the silicon wafer which will become the diaphragm of the sensor with a second material which alters an etching characteristic of the second selected portion; and (e) removing by etching at least a selected third portion of the silicon wafer adjacent to the first and second portions as part of forming the diaphragm and rim structure. Steps (c) and (d) are preferably performed by a deep diffusion and a shallow diffusion respectively of an impurity dopant, namely boron, into the silicon wafer.
According to a second aspect of the invention, there is provided an ultraminiature solid-state capacitive pressure transducer, comprising: an integrally formed structure made from single-crystal material and having a diaphragm and a rim extending about a substantial portion of the periphery of the diaphragm, the structure having at least two dimensions orthogonal to one another of less than one millimeter. The transducer typically includes a glass plate that is electrostatically bonded to at least part of the rim structure, and the single-crystal material is typically a silicon. The rim and diaphragm and heavily impregnated with at least a first material which alter an etching characteristic of the rim and diaphragm in comparison to single-crystal material which contains substantially less of such first material. The first material is typically a impurity dopant selected from a group of dopants including n-type materials and p-type materials, with the preferred p-type material being boron.
According to a third aspect of the present invention, there is provided a multipoint pressure-measuring catheter system, comprising: a catheter; a plurality of pressure sensors spaced along the catheter; and single conduit means within the catheter for providing a path for signals to be passed between an external monitor and each of the pressure sensors. The pressure sensors each include pressure transducer means for converting a sensed pressure into an internal signal, switching means for applying the internal signal to the signal conduit means, and addressing means responsive to a command signal from the external monitor for selectively interrupting switching means, whereby the external monitor may receive separately the internal signal generated by each of the pressure sensors.
These and other aspects, objects and advantages of the present invention will be better understood by reading the following detailed description in conjunction with the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings form an integral part of the description of the preferred embodiments and are to read in conjunction therewith. Like reference numerals designate identical components in the different Figures, where:
FIG. 1 is an exploded perspective view of an ultraminiature capacitive pressure sensor of the present invention which includes a silicon pressure transducer and integrated circuit chip mounted on a glass substrate;
FIGS. 2A-2H are a series of cross-sectional side views taken along line 2--2 of FIG. 1 showing the various processing steps associated with fabricating the silicon transducer from a silicon wafer, and bonding it to the glass support substrate;
FIG. 3 is a top cross-sectional view of the silicon pressure transducer of FIG. 1 after it is bonded to the glass substrate;
FIG. 4 is a plan view showing several completed glass silicon transducers from a matrix array of such chips which have been simultaneously bonded to a glass plate using the batch processing steps of FIG. 2, prior to dicing the plate into individual sensors;
FIG. 5 is a graph showing the capacitance change versus applied pressure characteristics of one ultraminiature pressure sensor constructed in accordance with the present invention;
FIG. 6 is a functional block diagram of a preferred embodiment for the on-chip circuitry used in the FIG. 1 pressure sensor;
FIG. 7 is a circuit diagram of the pulse amplitude discriminator module of FIG. 6;
FIG. 8 is a circuit diagram of the two-stage counter of FIG. 6;
FIG. 9 is a detailed block diagram of the Schmitt trigger oscillator module of FIG. 6;
FIG. 10 is a signal timing diagram showing waveforms and timing relationships of various signals in the circuitry illustrated in FIGS. 6-10; and
FIG. 11 is a multipoint pressure-sensing catheter system of the present invention which utilizes two of the FIG. 1 pressure sensors.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, an ultraminiature pressure sensor 30 of the present invention is shown in an exploded perspective view for ease of understanding. The pressure sensor 30 is comprised of three main components: a patterned glass support substrate 32 selectively metallized in certain areas, a patterned silicon transducer chip 34, and an interface circuit chip 36. The glass substrate has formed two therein grooves 40 and 42 at the left end 44 of the glass substrate 32, and a second pair of grooves 46 and 48 at the right end 50 of the glass substrate. Formed just beyond the inner end of the groove 40 and 42 are metallized bonding pads 60 and 62. Similarly, just beyond the inner ends of grooves 46 and 48 are metallized bonding pads 66 and 68. Typically, the grooves have a trapezoidal cross-section. The grooves 40, 42, 46 and 48 are metallized and are electrically connected respectively to pads 60, 62, 66 and 68. The grooves 40 and 42 receive wires 70 and 72, while grooves 46 and 48 receive wires 76 and 78. The wires 80, 82, 86 and 88 are respectively soldered or otherwise secured to grooves 40, 42, 46 and 48 prior to using the pressure sensor 30, as will later be described.
Upon the top surface 38 of the glass substrate 32 is a patterned metallized area or region 90 containing a first (rear) and second (front) interconnect traces 96 and 98, which follow the periphery of and are spaced from a metallized rectangular pad 100 which serves as one-half of the active capacitor C X of the pressure transducer of sensor 30, namely the lower plate of capacitor C. In region 90 are three metallized pads 106, 107 and 108 spaced apart from one another in a line perpendicular to the central longitudinal axis 105 of the glass support substrate 32. The first interconnect trace 96 is connected at one end thereof to pad 106, and at the other end thereof to pad 66. The second trace 98 is connected at one end thereof to pad 108 and at the other end thereof to pad 68. An enlarged view of the traces 96 and 98 and capacitor plate 100 is provided in FIG. 3. The circuit chip 36 contains a first set of beam leads 110 and 112, at the left and thereof, and a second set of beam leads 116, 117 and 118 at the right end thereof. As indicated by dashed lines 120, the circuit chip 36 is assembled to the glass support substrate 32 by flipping chip 36 over so that the beam leads 110, 112, 116, 117 and 118 respectively about against and may be bonded to bonding pads 60, 62, 106, 107 and 108 by ultrasonic bonding or thermocompression.
The patterned transducer chip 34 is preferably made from a conventional single crystal silicon wafer of the type widely used in the semiconductor industry. The chip 34 contains a very thin centrally located diaphragm 130 which is integrally connected to and surrounded by a much thicker rectangular rim 132. The rim 132 is preferably formed with at least two reference pressure inlet channels 133 and 134 respectively located on opposite sides of the rim, and which (until sealed off) provide access to a small space or chamber 135 under diaphragm 130. The silicon transducer chip 34 is electrostatically bonded to the glass substrate 32 in the location indicated in phantom by-dotted lines 136. The circuit chip 36 preferably contains all of the necessary read-out electronics, as will be further explained.
Key parts of the structure and process for making the pressure sensor 30 are the structure and process for making the transducer chip 34, and the process for joining of this chip to the glass substrate 32. This process and the resulting structure is illustrated in FIGS. 1 through 4.
The fabrication process starts with a 250 micron thick borosilicate glass plate 138 which may be a Corning 7740 glass plate, and which becomes the patterned glass plate 32 after processing. Since the height of the gap between the metallized capacitor plate 100 and silicon diaphragm 130 shown in FIG. 1 is typically less than 5 microns, a very smooth finish on both plates 100 and 140 are important in achieving high yield. Grooves 40, 42, 46 and 48 are first etched into the glass plate 32 with concentrated hydrofluoric (HF) acid using a gold/chromium mask. The gold/chromium mask is preferably formed in two layers by vacuum evaporation, with the chromium layer being about 200 to 400 angstroms thick and being deposited first, and the gold layer being about 3,000 to 5,000 angstroms thick. This mask is patterned using conventional photolithographic techniques so that the HF acid isotropically attacks the glass only in the area where the grooves are desired. Once the grooves are formed, the two layer mask is completely removed and a second multiple-layer conductive coating is deposited everywhere on the glass, and photolithographically patterned to form the appropriate metallized areas, namely grooves 40, 42, 46 and 48, bonding pads 60, 62, 66 and 68, interconnects 96 and 98 the lower plate 100 of the active capacitor (i.e., the transducer capacitor), and the metal pads 106, 107 and 108. Using batch processes, sites for numerous identical sensors 30 are created on a single sheet of glass 138.
The multiple-layer conductive coating may be made of a first layer of chromium about 300 angstroms thick for good adhesion to the glass substrate 32, and a second layer of gold about 2000 to 4000 angstroms thick for making good electrical contact with the wires, beam leads and the like connected thereto. Alternatively, a combination of three metal layers consisting of a first layer of titanium, a second layer of platinum, and third or top layer of gold could be used as the conductive coating. In this alternative conductive coating, the titanium and platinum layers should have a combined thickness of about 200 to 300 angstroms, while the gold layer should have a thickness of 2000 to 4000 angstroms. As is shown in FIG. 3, an area of overlap 139 between the rim 132 and the interconnect trace 96 in the vicinity of the metal pad 66 provides the electrical connection between the rim 132 and trace 96. The rim 132 serves as the conductive path leading to the top plate of the transducer capacitor, namely the silicon diaphragm 130.
Referring to the various views of FIG. 2, the processing of the silicon transducer chip 34 will now be explained. Starting with either n-type or p-type 100-oriented silicon wafer having a resistivity of about 6-8 ohm-centimeters, the wafer 140 is first cleaned. The wafer 140 is next thermally oxidized to a thickness of about 0.5 microns on all surfaces as indicated by a top layer 142 and bottom layer 144 of silicon dioxide in FIG. 2A. The wafer 140 is then coated with a layer of photoresist, which is then patterned in accordance with a first mask so as to leave resist in two flattened U sections 146 and 148 shown in FIG. 3, with cross-sectional portions of sections 146 and 148 thereof being shown in FIG. 2A. The wafers are aligned in a mask aligner so that the 110-orientation flat is parallel to the long side of the diaphragm 100. The silicon dioxide of top layer 142 is then patterned, and undesired areas thereof removed, leaving SiO 2 portions 152 and 154 located under the remaining photoresist portions 146 and 148. The photoresist portions 146 and 148 are then removed.
Next as shown in FIG. 2B, the shallow recessed sections 156, 158 and 160 are removed by etching the top of the silicon wafer 140 using potassium hydroxide as an etchant and the silicon dioxide portions 152 and 154 as a mask. The recesses 156-160 have positioned therebetween unetched mesas 162 and 164 respectively located under silicon dioxide portions 152 and 154. The recesses 156 and 160 provide the horizontal spacing between adjacent transducers, while the recess 158 forms the gap which become space 135 in the transducer capacitor. Next, the silicon dioxide portions 152 and 154 are etched away with buffered HF acid. Thereafter, a new layer of silicon dioxide is thermally grown to a thickness of about 1.2 microns and conforms to the existing mesa structure shape. It is then photolithographically patterned in accordance with a second mask whose geometry is depicted in FIG. 3 by large and small rectangles 176 and 178 shown in dashed lines. After this patterning, as shown in FIG. 2C, the silicon dioxide portions 178, 180 and 181 remain.
Referring again to FIG. 2C, the silicon wafer 140 is then impregnated in selected areas with etch-rate altering impurities by performing a deep boron diffusion, using the oxide mask portions 178, 180 and 181 to prevent the dopant gas from diffusing too far thereunder. This deep boron diffusion step defines the intended rim areas, such as rim portions 182 and 184. The deep boron diffusion is preferably performed at 1175 degrees C. for 15 hours using a solid dopant source (e.b., boron nitride) to provide a desired rim thickness as will be further explained. The doped wafer is then placed in a drive-in furnace at about 1100 degrees C. for 40 minutes to re-oxidize the surface boron-glass layer created during the previous step to a thickness of about 0.5 microns, as indicated by layer 188 of FIG. 2D.
Thereafter, as shown in FIG. 2D, a layer 190 of photoresist is deposited over the new oxide layer and patterned by removing all portions of the photoresist in the entire transducer area 192, i.e., the area within the large rectangle 176 indicated by dashed lines in FIG. 3. Thereafter, the silicon dioxide in the transducer area 192 is removed, thus leaving oxide layer portions 196 and 198 shown in FIG. 2E.
Next, as indicated in FIG. 2E, a short or shallow boron diffusion step is performed in the open transducer area within rectangle 176, including in the central region 200 between rim areas 182 and 184. The depth of this short boron diffusion is equal to the desired thickness for the silicon diaphragm 136. For a thickness of 2 microns, for example, the short boron diffusion step is performed at 1175 degrees Centigrade for 30 minutes.
Thereafter, if desired, the diaphragm area 136 may be covered with a dielectric layer for protection against electrical shorts and environmental contamination. The dielectric layer 204 is preferably a compound layer comprised of a first sublayer 205 of thermally grown oxide 1000 angstroms thick and a second sublayer 206 of CVD silicon nitride (Si 3 N 4 ) 1000 angstroms thick. The resulting composite layer 204 is nearly neutral in stress (or in mild tension). By altering the thickness of its sublayers, such a composite layer 204 can be readily adjusted to have a temperature coefficient closely matching that of the underlining silicon diaphragm 136. The dielectric layer 204 is initially grown and deposited over the entire wafer 140, as indicated in FIG. 2F. Next, the dielectric layer 204 is removed over all areas, other than the diaphragm 136. This is done as follows. A layer 207 of photoresist is applied and patterned using a fourth mask having a geometry corresponding to the inside rectangle 178 shown in FIG. 3, so that a patterned photoresist portion 208 remains and covers the diaphragm area. Then, using a plasma (dry) etch of silicon nitride, followed by a buffered HF (wet) etch to remove the oxide layer, the dielectric layer 204 is removed from all areas of wafer 140 other than the diaphragm 136, so that only dielectric layer portion 210 remains, as best seen in FIG. 2G. The same buffered HF etch also removes the back side oxide layer 144.
Thereafter, a bonding step is performed, as illustrated in FIG. 2G, wherein the silicon wafer 140 is batch bonded to the glass plate 32 using an electrostatic (anodic) bonding technique. The alignment of the silicon wafer 140 to the glass substrate 32 is straightforward since the glass is transparent. The bonding is preferably formed by heating the assembly 212 of the wafer 140 and glass substrate 32 to between 400 and 450 degrees C., and then applying 400 to 600 volts DC from a suitable power source 214 across the glass plate 32 and silicon wafer 140 for two minutes. This forms a hermetic seal between the rim structure (e.g., rim portions 182 and 184) of the wafer 140 and the glass 32. The electrostatic bonding of a silicon wafer to glass is widely used to construct other types of silicon capacitive pressure transducers. See for example, Y. S. Lee and K. D. Wise, "A Batch-Fabricated Silicon Capacitive Pressure Transducer With Low Temperature Sensitivity", IEEE Transactions on Electron Devices, Vol. ED-29, No. 1, pp. 42-48 (Jan. 1982), which is hereby incorporated by reference. Thus, the electrostatic bonding step need not be further described here.
Following the bonding step, the silicon wafer glass assembly shown in FIG. 2G is immersed in an anisotropic etchant for silicon (such as ethylene-diamine/pyrocatechol/water (EDP)) and all of the silicon wafer 140 is dissolved, except for the boron doped rim portions of the wafer, such as rim portions 182 and 184, and diaphragm 136 therebetween. Thus, only the boron-doped portions of the wafer 140 are retained, and these portions constitute the patterned transducer chip 34 shown in FIG. 1. These portions do not etch in EDP, nor do the interconnect metals, the glass, or the oxide or other dielectric layers. The result of this etching operation is a glass plate 32 containing a glass-silicon transducer 220 as shown in FIG. 2H.
FIG. 4 shows a portion of a glass substrate 138 having eight glass substrates 32 prior to being diced into individual substrates. The four substrates 32 in the center are shown with completed glass-silicon transducers 220 of the type shown in FIG. 2H. (To avoid cluttering the Figure, the glass substrates 32' are shown without their transducers 220.) As can be readily appreciated by those skilled in the art, the fabrication process described with respect to FIGS. 1-3 is fully compatible with automated batch processing techniques which will allow the transducers 220 to be prepared en masse, that is by the hundreds (or more) from a single silicon wafer. The glass substrates 32 shown in FIG. 4 are diced along the vertical and horizontal dashed lines 222 and 224 to separate then into individual substrates 32.
As should be evident from the foregoing, the transducer process described above utilizes single-sided processing of silicon wafers having normal thickness. It requires only three non-critical masking steps to produce the patterned silicon wafer diaphragm and rim structure or chip 34, and produces a very high yield. (IF the optional dielectric SiO 2 --Si 3 N 4 layer is used, then a fourth mask is required.) The rim and diaphragm thicknesses are set by the deep and shallow boron diffusion steps with a precision of better than 0.1 microns, while lateral dimensions are controlled by lithography to a precision of better than 0.25 microns.
The rim size is scalable, but is typically 12 microns thick and 80 microns wide. This is significantly smaller than those found in conventional pressure sensing structures, in which the diaphragm is formed from a back side anisotropic etch, and the width of the rim is comparable to the wafer thickness (300 microns or more). Furthermore, in the present approach, batch wafer bonding to the glass before wafer dissolution eliminates handling of individual diaphragm structures until die separation and final packaging. The glass 138 may be sawed into individual dies (i.e., glass plates 32) before or after the bonding of the chips 36 to the metal pads 60, 62, 106, 107 and 108.
FIG. 5 shows the measured pressure characteristics of the ultraminiature sensor illustrated in FIG. 1. The reference cavity 135 for the sensor 130 upon which the measurements were made was sealed and at atmospheric pressure. However, differential pressure measurement with an unsealed reference pressure inlet channel 134 is also possible with the transducer 220. The sensor 30 upon which the measurements shown in FIG. 4 were made had a diaphragm size of 260 microns×600 microns×2 microns, a capacitor plate separation of 2.2 microns, a zero-pressure capacitance of 0.33 pF, a pressure range of about 500 mmHg and a pressure sensitivity of 1440 ppm/mmHg. By scaling lateral and vertical diaphragm dimensions, the pressure sensitivity of the transducer 220 can be scaled over several orders of magnitude.
The small size of the capacitance change associated with the sensor and the need to simplify packaging by minimizing external leads poses a challenge to the design of the circuit chip. An oscillatory-type circuit which requires only two external leads has been developed in which the supply current is pulse-period modulated by the applied pressure. A functional block diagram of this circuit is shown in FIG. 6. The circuit 250 includes a pulse amplitude discriminator circuit 252, a two-stage counter 254, and a Schmitt trigger oscillator circuit 256 including a Schmitt trigger oscillator 258, an enable switch 260, and a two-position selector 262. Electrical power and signal communication is delivered over conductors 266 and 268 which respectively are nominally at a solid-state circuit supply voltage VDD (such as +5 VDC) and ground potential GND (0.0 volts). The operation of circuit 250 may be explained in brief as follows. Schmitt trigger oscillator 258, in which the period of oscillation is dominated by the charging time of the transducer capacitance C X , sets up an oscillation in the supply current delivered via conductors 266 and 268. The electrical pressure signal originating with capacitor C x is then extracted by detecting the frequency of current variations over the power lines 266 and 268. Tradeoff between pressure signal bandwidth and resolution can be attained by altering the length of the sampling time. Temperature compensation is accomplished by differencing the oscillation period produced using the transducer with that of an on-chip reference capacitor C R which may be a thin film capacitor integrally fabricated with the other circuit components on circuit 250 in IC chip 36. The reference capacitor C R , together with the temperature coefficient of the circuit supplying power to capacitor C R , also serves as a transducer for on-chip temperature readout. Site and pressure/temperature transducer addressing is accomplished by signaling over the supply line 266 to circuit 252, which triggers an on-chip counter 254 and allows one particular sensor on a bussed multisensor line to be activated, while inactivated oscillator circuits such as circuit 256 are disabled. Thus multisite operation is possible. By depositing a thin film metal resistor having a high temperature coefficient of resistance on the diaphragm 130, it is possible to measure dynamic changes in temperature as well as pressure at each sensing site to allow future thermal dilution measurements of blood flow.
The addressable read-out circuit 250 in FIG. 5 may be fabricated on a single integrated chip such as chip 36 shown in FIG. 1. Prototypes of the chip 36 have been fabricated using standard NMOS processing, with beam leads to allow low-capacitance low-profile high-density interconnects to the transducer 220 and output leads 60, 62, 66 and 68 via the glass substrate 32. Use of a hybrid arrangement, as shown in FIG. 1 where the IC chip 36 and pressure transducer 200 are separately fabricated and then connected together, has several important advantages: (1) the circuits 250 can be processed using standard IC fabrication techniques and may be realized using a chip foundry; (2) the circuitry 250 is not exposed to the high voltage needed for the electrostatic bonding process; and (3) working circuit chips 36 can be selected for bonding to transducers 220, thus improving yield.
FIG. 7 shows a detailed circuit diagram of the pulse amplitude discriminator circuit 252. The circuit 252 contains seven metal-oxide-semiconductor (MOS) insulated-gate field effect transistors (FETs) 270 through 282. FETs 270-274 are enhancement-mode devices, while FETs 276-282 are depletion-mode devices. The circuit 252 receives power over supply lines 266 and 268, and receives two different types of commands over supply lines 266. The nominal voltage VDD is +5 volts DC. The first command signal is a clock signal which is delivered at +8 volts DC. The second command signal is a reset signal which is delivered at +11 volts DC. The first command signal is shown in FIG. 10 on waveform 284. The pulses 286 are the clock pulses. The circuit 252 produces three outputs signals, namely the RESET on line 290 and the MODE and MODE* signals on lines 292 and 294. A waveform 296 in FIG. 10 shows the timing and voltage levels of the MODE signal. The MODE* signal is the complement of the MODE signal. (The asterisk symbol is used to indicate the complement of whatever signal it follows.) The operation of circuit 252 in FIG. 7 may be briefly explained as follows. When VDD line 266 temporarily goes to 8 volts, it draws node 300 to a sufficiantly high level, causing gate 298 of transistor 272 to go high, which turns transistor 272 on. Accordingly, MODE* goes from a high to a low logic level, and transistor 274 turns off, which makes the MODE signal on line 292 switch from a low logic level to a high logic level. When VDD line 266 returns to 5 volts, gate 298 returns to a low logic level causing transistor 272 to turn off. Accordingly, the MODE* signal switches from a low to high logic level, and transistor 274 turns on, which causes the MODE signal on line 292 to switch from high to low. When the VDD line goes to 11 volts, indicating a RESET command, it draws reset line 290 from a low to high logic level.
FIG. 8 is a circuit diagram of the two-stage counter circuit 254 shown in FIG. 6. The circuit 254 includes a first stage 310 and a second stage 312 interconnected by a single conductor 314. The output signal P on line 316 of first stage 310 is the low-order bit output of counter 254, while the output signal CE (which stands for Chip Enable) is the output for the high-order bit of counter 254. The first and second stages 310 and 312 each receive the MODE, MODE* and RESET signals respectively from lines 292, 294 and 290. The circuit 254 provides as outputs the P and P* signals on lines 316 and 320 respectively from the first stage 310, and provides as outputs the CE and CE* signals on lines 318 and 270 of the second stage 312. In the FIG. 10 graph, waveforms 322, 324 and 326 show the timing relationships for signals P, P', and CE respectively.
As shown in FIG. 8 the first stage 310 includes inverter 330, MOSFET 332, NOR gate 334, inverter 336 and MOSFETs 338 and 339, all connected as shown. The second stage 312 includes: inverter 340, MOSFETs 341 and 342, NOR gate 344, inverter 346 and MOSFETs 348 and 349, all connected as shown. The operation of stages 310 and 312 will now be briefly explained, and it will be assumed that the RESET line 290 remains at a low logic level, which causes NOR gates 334 and 344 to each function as a simple inverter. As long as the MODE* signal remains high, the transistors 338 and 348 conduct. In stage 310, the NOR gate 334 and inverter 336 act as a latch to hold on the signal present on line 320 whenever transistor 338 is on and transistor 332 is off. Similarly, in stage 312, the NOR gate 344 and inverter 346 act as a latch whenever transistor 348 is on (that is, conducting) and transistor 341 or 342 is off. Returning now to first stage 310, assume line 314 (the P' signal) is low. When the mode signal arrives on line 292, transistor 332 turns on, causing line 350 to go low irrespective of its previous state, which causes line 316 to go high and line 320 to go low. While the MODE signal on line 292, the MODE* signal on line 294 is low and transistors 338 and 339 are off. When the MODE signal on line 292 goes low, transistors 338 and 339 turn on, thus latching in the low signal on line 320 and simultaneously supplying a low signal on line 352 going to the input of inverter 330. This causes the output of inverter 330 and line 314 to go high. However, since transistor 332 is now off, the high signal on line 314 is unable to propagate through to line 350 at this time. When the mode signal on line 292 goes high again, the high signal on line 314 propagates through to line 350, thus causing line 316 to go high and line 320 to go low. When the mode signal goes low again, the low state of line 320 is latched in via transistor 338. Thus, it will be appreciated that the output 316 and 320 of first stage 310 change state each time that the mode signal on line 292 goes high.
In contrast, the outputs 318 and 270 of the second stage 312 toggle, that is, change state, only with every second time that the MODE signal on line 292 goes high. This is because the stage 312 contains an additional transistor 341 which only allows the output signal CE* on line 270 to change state when the MODE signal on line 292 and the signal on line 314 from stage 310 are both high. In all other respects, the operation of stage 312 is the same as stage 310. Note that when the RESET signal on line 290 goes high, the outputs of NOR gates 334 and 344 are forced low irrespective of the state of input lines 350 and 356, thus causing both the P signal on line 316 and the CE signal on line 318 to go low. Transistors 338 and 348 if on will latch in this RESET output state.
FIG. 9 shows a detailed block diagram of the trigger oscillator circuit 256 shown in FIG. 6. The circuit 256 includes a MOSFET 360, which acts as the enable switch 260. In the circuit 256 shown in FIG. 9, the switch 260 is turned on whenever the gate input line 270, containing the enable signal CE* from the second stage 312 of the counter 254 is high. In another circuit 256', (not shown) the input to transistor 360 would be the output signal CE on line 318 from the second stage 312 of counter 254. Since the enable switch 260 must be on in order to for the oscillator circuit 256 to operate, it will be appreciated that the input signal to transistor 360 is effectively an address signal which must be high in order for the oscillator circuit 256 to be addressed. The Schmitt trigger oscillator 258 consists of three components, namely an inverting Schmitt trigger 362, inverter 364 and a source 366 of approximately constant current which is provided at a predetermined level from supply line 266 to output line 368. The current source 366 is set to produce the desired rate of charging of the transducer capacitor C X and the reference capacitor C R shown in FIG. 9. The switching circuit 262 includes four enhancement-mode MOSFETs 370-376. The operation of circuit 256 will now be briefly explained. When circuit is enabled by a high signal on the input of transistor 360, and the output of inverter 364 on line 378 is low, transistors 372 and 376 will be off, thus permitting capacitors C X and C R to charge. When signal P on line 316 is high, transistor 370 is on, thus allowing transducer capacitor C X to charge, and the reference capacitor C R will not charge since the complementary signal P* on line 320 will be low. Conversely, when the signal P* on line 320 is high, transistor 374 will be on, thus allowing reference capacitor C R to charge, while transistor 370 will be off, so that capacitor C X cannot charge. The rate at which the capacitor C X and C R charge is determined by the rate at which current is supplied to line 368 from the constant current source 366. When either capacitor C X or C R charges to a predetermined threshold voltage level which exceeds the input threshold voltage required to turn Schmitt trigger 362 on, output of Schmitt trigger 362 on line 380 goes low, which causes the output of inverter 364 on line 378 to go high. This turns on transistors 372 and 376, discharging both capacitors C X and C R . The voltage on line 368 immediately approaches zero volts, thus resetting the Schmitt trigger 362 and allowing the output of inverter 364 to go low high, which turns off transistors 372 and 376. At this point, either capacitor C X or C R is allowed to begin charging again.
Waveform 382 in FIG. 10 illustrates the operation of the FIG. 9 circuit by showing the output voltage VOUT on line 368. As shown in FIG. 10, the time period T X between t1 and t2 represents the interval during which the transducer capacitor C X is being repetitively charged and discharged by circuit 256. Similarly, the time period T R between times t0 and t1 represents the interval of time during which the circuit 256 is charging and discharging the reference capacitor C R . During the time period T OFF from times t2 to t4, the circuit 256 shown in FIG. 9 is disabled, thus allowing the voltage VOUT on line 368 to approach the value of voltage VDD on line 266 as shown by waveform portion 384 of waveform 382 in FIG. 10. Since the constant source 366 may be measured or otherwise calibrated at a known temperature, any change in the rate of charging of reference capacitor C R can be correlated with reasonable accuracy to changes in temperature of the integrated circuit chip 336 in which capacitor C R is located. Given the small size of the sensor 30, and the proximity of capacitor C R to the diaphragm 130, it will be appreciated that C R provides a convenient and accurate method for determining the temperature of the pressure transducer of sensor 30, so that the pressure readings obtained from the charging time of transducer capacitor C X can be accurately compensated for temperature by an external monitoring system which examines the charging rates of capacitors C X and C R . These charging rates are monitored by monitoring the frequency of the current signal drawn by circuit 252 over power supply lines 266 and 268. As is well understood by those in the art, the amount of pressure applied to the diaphragm 130 of pressure transducer 220 directly influences the capacitance value of capacitor C X . For example, as pressure increases, the capacitance value increases. Since changes in the capacitance value of capacitor C X results in proportional changes in the charging time of capacitor C X , the pressure being applied to the diaphragm 130 can be readily determined by monitoring the frequency of the current signal on power lines 256 and 268 when capacitor C X is allowed to charge by transistor 370 being on, and transistor 372 being off, as has been discussed with respect to FIG. 9.
As will be readily understood by those skilled in the art, the pressure transducer 220 of sensor 30 can be operated in several ways. For example, the pressure transducer 220 can be sealed at ambient pressure, or under vacuum conditions. If sealed at ambient pressure, epoxy or other suitable sealing materials can be deposited at the openings of both reference channels 133 and 134 (see FIGS. 1 and 3). One disadvantage of sealing gas in the cavity or chamber 135 of the pressure transducer 220 is that it results in a pressure transducer which has a high temperature coefficient on account of the pressure of the trapped gas naturally changing within sealed chamber 135 as the gas temperature changes. If the transducers 200 are to be sealed under vacuum conditions, this may be done en masse simultaneously while they are still on the glass plate 138 before the glass plate sections 32 are diced into individual glass plates, by depositing a dielectric material with sealing properties directionally through a shadow mask at the mouth or opening of each of the reference channels 134 and 135. This task can be carried out in a sputtering chamber using silicon dioxide (or the like) as the sealing material using a shadow mask which only has openings above the reference channels.
Referring now to FIG. 11, an ultraminiature catheter system 400 is shown. The system includes a very small catheter 402 such as 0.5 mm outer diameter (OD) tubing made from polyethylene or other suitable material, which has a length sufficient for the medical (or other) purpose to which the catheter will be placed. The system shown has two pressure sensors 30a and 30n, which are preferably constructed like sensor 30 shown in FIG. 1, spaced apart by a predetermined distance 404 such as 5 cm. The catheter 402 has three distinct sections: a catheter tip section 406, preferably round and gently pointed as shown to facilitate insertion into and passage along the interior of smaller blood vessels; an intermediate section 40 between the two pressure sensors 30a and 30b; and an extension section 410 to provide a conduit through which the wire leads 266 and 268 from electronic pressure sensor monitoring equipment may pass to reach the first and closest sensor 30a.
Preferably, the catheter system uses only the two wire leads 266 and 268 which are electrically connected in parallel to the two sensors 30a and 30n, while physically being arranged in series. Prior to the assembly of the catheter system 400 the pressure sensors 30a and 30n, which each include a glass plate 32 with the transducer chip 34 and read-out electronics chip 36 mounted thereon, is partially encapsulated with a biomedically compatible material 414 (i.e., one that is non-toxic and will not be adversely affected by the bodily fluids to which it be exposed) such as polyimide, silicone rubber, or the like, to seal off the hollow cylindrical interiors of the catheter sections from bodily fluids. The diaphragm 130 may have encapsulating material upon it, provided that the thickness of the layer of material upon the diaphragm is controlled so as to be at least about an order of magnitude more flexible than the silicon diaphragm 310. The integrated circuit chip 36 is preferably within the dry interior of the catheter section 408 (or section 410) where it will not be contacted by bodily fluids.
The required catheter leads 266 and 268 are attached via soldering or the like into the etched grooves 40, 42, 46 and 48 as has been explained in FIG. 1. Finally, the ends of the glass plates 32 are inserted in the catheter 402, leaving only the silicon diaphragms 130 exposed for measurement.
Prototypes of the above-described multipoint pressure-sensing catheter system have been fabricated and successfully tested. Table I below provides typical specifications for our prototypes.
TABLE 1______________________________________Catheter Size 0.5 mm ODDiaphragm Size 290 × 500 × 2 micronsTransducer Die Size 0.45 × 1 mmCircuit Die Size (Prototype) 0.45 × 1.1 mmZero-Pressure Capacitance 470 fFPressure Accuracy 1 mmHgPressure Range 500 mmHgSignal Bandwidth 50 HzTemperature Compensation Frequency Differencing Using an On-Chip Reference CapacitorPower Supply Single 5 VSignaling Levels 8 Volts - Addressing, 11 Volts - ResetPower Dissipation less than 10 mWOutput Signal Small-Signal Supply Current Variation (600 A p-p Over 850 microamps dc Baseline)Number of Sensing Sites 2Number of Transducers/Site 2 (Pressure/On-Chip) Temperature)Number of External Leads 2______________________________________
It is recognized that those skilled in the art may make various modifications or additions to the preferred embodiments chosen to illustrate the invention without departing from the spirit and scope of the present contribution to the art. For example, the pressure transducers of the present invention may be made much larger or smaller than the embodiments described herein by appropriate scaling of various dimensions. Also, the pressure transducer of the present invention may be used to sense fluid flow and other conditions by providing appropriate means for causing deflection of the diaphragm are provided. Accordingly, it is to be understood that the protection sought and to be afforded hereby would be deemed to extend to the subject matter claimed and all equivalents thereof fairly within the scope of the invention. | A capacitive pressure sensor suitable for making highly sensitive, low pressure measurements is disclosed. The sensor may be mounted into a 0.5 mm OD catheter suitable for multipoint pressure measurements from within the coronary artery of the heart. The sensor employs a tranducer which consists of a rectangular bulk silicon micro-diaphragm several hundred microns on a side by two microns thick, surrounded by a supporting bulk silicon rim about 12 microns thick. Both the diaphragm and the rim are defined by a double diffusion etch-stop technique. The transducer fabrication process features a batch wafer-to-glass electrostatic seal followed by a silicon etch, which eliminates handling of individual small diaphragm structures until die separation and final packaging. An addressable read-out interface circuit may be used with the sensor to provide a high-level output signal, and allows the sensor to be compatible for use on a multisite catheter having only two electrical leads. | 8 |
FIELD OF THE INVENTION
The present invention relates to a process for preparing a bean jam. More particularly, the present invention relates to a process for preparing a bean jam, in which adzuki bean (Vigna angularis) or the other beans including soybeans (referred to hereinafter as "adzuki beans") and water used for preparing bean jams are applied with high voltage negative electrons.
DESCRIPTION OF THE PRIOR ART
The operation for removing the astringent ingredients contained in adzuki beans has been conventionally conducted by washing the starting beans with water and repeating the cooking of the beans in a cooker. It is generally required for removing cyanic compounds contained in beans to soak the starting beans for at least four hours in warm water, to cook the beans for several hours and to refine the resulting bean jams in water at least three times. Soybeans have being unsuitable as a starting material for bean jams, because of having a high content of water-soluble ingredients. Moreover, they are not used entirely as the starting material, because of their having a peculiar beany flavor.
For producing bean jams of adzuki beans, a large amount of water is used, a high level of heat energy is lost accordingly, and a period of at least 4-6 hours is required for preparing one batch of bean jam, so that the daily production amount per unit is limited.
In addition, as the astringent ingredients of adzuki bean or the cyanic compounds cannot be removed sufficiently during the soaking and cooking steps, a large amount of water is also required for the refining step. However, criteria for discharging waste water has recently become severe and drainage from factories is restricted. It has also been considered impossible to remove astringent ingredients or cyanic compounds by using water and to remove the beany flavor even by soaking and cooking the soybeans according to the conventional method.
SUMMARY OF THE INVENTION
The present inventor has found that the above-mentioned problems can be solved by applying high voltage negative electrons without flowing entirely an electric current on red beans and water for preparing bean jam while a pole at a secondary higher voltage side of a high voltage electrostatic transformer is completely sealed and insulated and a high output resistance is provided at another pole, and affording activation energy to the adzuki beans and the water.
That is, while the astringent ingredients or cyanic compounds could not be removed sufficiently even by soaking adzuki beans in water at an ordinary temperature, it has become possible to remove astringencies such as tannin and gummy materials or cyanic compounds by using the adzuki beans or water activated according to the present process. When the present process is used to soybeans, not only is the beany flavor removed, but also the lees formed are reduced and the yield of bean jam may be improved.
According to the process of the present invention, the removal of the astringent ingredients or cyanic compounds, which could conventionally be done only incompletely, even at the latter step (cooking step), has been successfully done at the former steps (washing and soaking steps). Moreover, adzuki beans activated by the present process enhances extensively the heating efficiency, reduces the cooking period and decreases the cracking of the beans. It has thus become possible to manufacture economically and quickly the bean jam having an excellent and mild taste. Furthermore, it has been possible as the secondary effect to use the stock itself (soup) of the beans as a high quality "Shiruko" (stock), since the astringent ingredients or cyanic compounds can be completely removed at the former steps.
The adzuki beans and the water used according to the present invention is activated by the following treatment conditions. A high voltage electrostatic transformer is used, and a pole at a secondary higher voltage side is completely sealed and insulated, while another pole is connected to a plate or container of an electroconductive material which is completely insulated from the earth without flowing, entirely, any electric current. The plate or container of an electroconductive material is used as an electrode, with which the adzuki beans are brought into contact by filling them in the plate or container for applying a high electrostatic voltage.
As for the appropriate negative electron generating conditions in this case, the electric current at the primary side of the high voltage electrostatic transformer of 100 V is in the range from 0.02 A to 0.3 A per 1 m 2 of electrode, and the electric voltage at the primary side in the range from 5,000 V to 20,000 V is required. The application time is preferably in the range from 2 to 100 hours. While the plate or container of the electroconductive material used in the present invention is of metallic materials such as iron and stainless steel or carbon materials, the activation treatment of the present invention may be further improved particularly by coating the surface opposite to that contacting the starting adzuki beans with a non-electroconductive material such as plastic material. When a non-electroconductive container is used, it is also possible to conduct electronic treatment under the aforementioned condition by inserting an electroconductive material as an electrode in the starting adzuki beans.
In order to accomplish sufficiently the object of the present invention, it is necessary to conduct the activation treatment of not only the starting adzuki beans but also water used for the soaking of the beans and for manufacturing the bean jam. The activation treatment of the water is conducted by using a high voltage electrostatic transformer in the same manner as the activation treatment of the beans and applying negative electrons on a water tank. That is, when an electroconductive container which is completely insulated from the earth is filled with the water and connected to the aforementioned high voltage electrostatic transformer or when a non-electroconductive container is used, it is also possible to insert an electroconductive material plate as an electrode into the water in the same manner as the beans and to conduct treatment under the same condition as above. While the application condition is the same as the case of the beans, the application time of the water is desirably at least 8 hours. The treatment effect of the present invention may also be enhanced by removing chlorine and the like from the water.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is the cross-sectional view of the container into which the beans have been filled.
FIG. 2 is the sectional view of the apparatus for activating water used for preparing the bean jam.
Explanation of the symbols:
1. Apparatus for generating negative electrons by electrostatic induction;
2. Electron treatment tank and electroconductive part;
3. The beans such as adzuki beans and soybeans;
4. Insulating part;
5. Insulating container;
6. Water;
7. Electroconductive part;
8. Activated carbon tank.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is further described with reference to examples.
As shown in FIG. 1, in preparing the examples, 30 kg of adzuki beans (domestic or Chinese strain), 40 kg of butter beans from Myanmer, 40 kg of baby Lima from the United States and 60 kg of soybeans from China were used, respectively, and were each charged in a stainless steel container on a plastic insulating pallet, and a pole of a high electrostatic transformer was connected to the container. The domestic beans were treated for 48 hours, the Chinese adzuki beans and soybeans for 72 hours, and the butter beans and the baby LIMA for 96 hours. Also, as shown in FIG. 2, a 1 m 3 amount of the water which had been passed through an activated carbon tank on a plastic insulating pallet was charged in a polyethylene container, a stainless steel plate as an electrode was provided in the water, and a pole of the high voltage transformer was connected to the electrode plate for conducting the treatment for 12 hours. The water has a pH value of 6.9 before the treatment and 7.5 after the treatment.
Example 1
The adzuki beans and/or the water treated as above and those without treatment were subjected to soaking test at room temperature. The amount of the water absorbed per 1 kg of the adzuki beans and the pH value of the water after soaking are shown in Tables 1 to 3.
TABLE 1______________________________________(1) Domestic adzuki beans (small) 6 hours 12 hours 18 hours Amount of Amount of Amount of water water waterSoaking time absorbed pH absorbed pH absorbed pH______________________________________Both beans 80 6.2 690 6.0 1030 5.6and watertreatedOnly beans 70 6.7 520 6.3 830 6.0treatedOnly water 70 6.8 560 6.5 930 6.0treatedNeither 60 7.0 420 6.8 760 6.7beans norwater treated______________________________________
TABLE 2______________________________________(2) Domestic adzuki beans (large) 6 hours 12 hours 18 hours Amount of Amount of Amount of water water waterSoaking time absorbed pH absorbed pH absorbed pH______________________________________Both beans 70 6.4 500 6.3 980 5.8and watertreatedOnly beans 60 6.8 400 6.6 870 6.1treatedOnly water 65 6.7 410 6.5 880 6.2treatedNeither 50 6.9 330 6.8 680 6.6beans norwater treated______________________________________
TABLE 3______________________________________(3) Chinese adzuki beans 6 hours 12 hours 18 hours Amount of Amount of Amount of water water waterSoaking time absorbed pH absorbed pH absorbed pH______________________________________Both beans 130 6.2 880 6.0 1400 5.6and watertreatedOnly beans 110 6.6 720 6.3 1180 5.9treatedOnly water 110 6.8 760 6.4 1230 5.8treatedNeither 90 6.9 600 6.6 1020 6.2beans norwater treated______________________________________
Example 2
A 30 kg amount of the domestic adzuki beans (small) was soaked in 60 liters of the treatment water for 12 hours. The beans were then taken out and placed in a cooker to cook with 45 liters of the treatment water for 13 minutes. Removal of the soup gave 7.6 kg of a grained bean jam. The grained bean jam had a good texture, of no astringency and rich in the sweetness and flavor of adzuki beans. Besides, the soup could be used as a high quality shiruko soup.
Similarly, beans jams were prepared with the treatment of adzuki beans, the treatment of only water and the treatment of both beans and water under the same conditions as above.
TABLE 4______________________________________ Sugar Cooking Yield of contentSoaking time bean jam of bean Astring-time (min) (kg) jam (bx) ency Color______________________________________Both 13 76 8 none purplishadzuki graybeans andwatertreatedOnly beans 16 73 4 scarecely graytreated anyOnly water 15 74 5 scarecely graytreated anyNeither 25 68 2 notable brownishbeans nor graywatertreated______________________________________ (Sugar content was measured with a saccharimeter.)
(2) Bean jam was prepared under the same conditions except that the domestic adzuki beans (small) in (1) were replaced by the Chinese beans.
TABLE 5______________________________________ Sugar Cooking Yield of contentSoaking time bean jam of bean Astring-time (min) (kg) jam (bx) ency Color______________________________________Both 23 68 6 none purplishadzuki graybeans andwatertreatedOnly beans 38 62 4 a little graytreatedOnly water 42 61 4 scarecely graytreated anyNeither 85 50 2 notable brownishbeans nor graywatertreated______________________________________
Example 3
(1) A 40 kg amount of the butter beans from Myanmer treated as above was soaked in 80 liters of the treated water for 12 hours. The butter beans were placed in a cooker, cooked with 60 liters of the treated water before removing the astringent ingredients once and further cooked with 60 liters of the treated water for 30 minutes.
Similarly, beans jams were prepared with non-treated butter beans and non-treated water under the same conditions as above.
TABLE 6______________________________________Amount of After onceresidual cyanic After removing Aftercompounds (ppm) soaking astringency cooking______________________________________Treated 7 undetectable undetectableproductsNon-treated 250 210 75products______________________________________ (The amount of the cyanic compounds of the butter beans is 360 ppm.)
(2) Tests were conducted under the same conditions except that the butter beans in (1) were replaced by the baby LIMA (US product).
TABLE 7______________________________________Amount of After onceresidual cyanic After removing Aftercompounds (ppm) soaking astringency cooking______________________________________Treated 6 undetectable undetectableproductsNon-treated 220 180 30products______________________________________ (The amount of the cyanic compounds of the baby LIMA is 320 ppm; the cyanic compounds are detected by the ion electrode method.)
As is apparent from the examples, it is considered that when the adzuki beans and the water are treated according to the process of the present invention, the cells of the beans themselves are activated, and the clusters of water molecules are decreased to increase soaking power into the raw material, so that the aforementioned advantageous effects are accomplished. However, the mechanism thereof cannot be precisely understood.
It is found from the data shown in Tables 1 to 3 that the treated products absorb water more rapidly and in a larger amount as compared with the non-treated products. Furthermore, the drop of pH is caused by the leaching of acids in the beans.
It is found from the data shown in Tables 4 and 5 that judging from no astringency and the color of the bean jam made of the treated products, tannin, gummy materials in seeds and seed leaves and the other materials which impair the flavor have been completely bled out with water at room temperature. Moreover, the heating ability and the thermal conductivity of the beans were improved, so that the cooking time was successfully reduced to about 1/2-1/4 time with increasing the yield of the bean jam by 12%-38% and the sugar content to three or four times.
It has been found from the data shown in Tables 6 and 7 that 98% or more of the cyanic compounds in butter beans or baby LIMA have been removed by soaking into water at room temperature. After the astringent ingredients have been once removed, no cyanic compounds were detected. However, the astringent ingredients were removed by only 30% from the non-treated product, and the cyanic compounds could not be extracted with water at room temperature. As a conclusion, while better results can be obtained by applying high negative electron on only the adzuki beans or the water as compared with the conventional method as shown in Tables 1 to 7, it is more preferable to conduct the treatment of both the beans and the water.
Example 4
After 60 kg of soybeans from China treated as above were soaked in 20 liters of the treated water for 10 hours, the beans were charged in a cooker and cooked with 180 liters of the treated water for 4 minutes. After removing the soup formed on cooking therefrom, the beans were ground with a masher while adding an appropriate amount of the activated water and then separated into the bean meat and skin with a separator. The mashed jams of the soybean were prepared from the resulting content according to the conventional method. The jams had no beany flavor, had a viscous texture and were rich in sweetness. In addition, only a small amount of lees was formed.
Similarly, soybean jams were prepared with the treatment of only soybeans, the treatment of only water and no treatment of both beans and water under the same conditions as above.
TABLE 8______________________________________Cooking Yield of Amount ofTime Jam Lees Beany(min) (kg) (kg) flavor Color______________________________________Both 10 120 15 None Creamysoybeans whiteand watertreatedOnly beans 16 100 65 A little Creamytreated yellowOnly water 14 105 60 A little Creamytreated yellowNeither 25 75 150 Not- Yellowbeans nor ablewatertreated______________________________________
As is shown in Table 8, the cooking time with the treatment of both soybeans and water lowers to half or less than that with non-treatment and yield of the jams resulted in an extraordinary 60% increase. In addition, the amount of the lees was 1/10. That is, it appears that the skin of the soybeans was very much softened by activating the starting beans and water to obtain a jam component, and accordingly only the hard portion remains as the lees which are not viscous and dry to the touch.
Recently, treating such lees of Tofu curd constitutes a social problem in their utility, because of having a high moisture content, but the lees formed by the present process have relatively low moisture of about 65% and a long shelf life. The products according to the present invention have no beany flavor and may be utilized for various food products. Moreover, they are utilizable as a white bean jam in view of their color and sweet taste as well. | A process for preparing a bean jam is disclosed wherein adzuki beans or other beans and water are separately applied with high voltage negative electrons of 5,000 V to 20,000 V to separately produce treated beans with enhanced bean jam-producing properties and a treated water, the treated beans and the treated water are combined and heated to produce bean jam and stock, and the resulting bean jam is then removed from the stock. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a national stage patent application filed under 35 U.S.C. §371, claiming priority to International Serial No. PCT/MX2007/000077, filed on Jun. 22, 2007, which claims the benefit of U.S. Ser. No. 11/669,335, filed on Jan. 31, 2007, entitled “Method and Apparatus for Dispensing Paste-Like Substances,” the technical disclosure of which is hereby incorporated by reference.
[0002] This application is also being filed as a continuation-in-part of co-pending U.S. Ser. No. 11/669,335, filed on Jan. 31, 2007, entitled “Method and Apparatus for Dispensing Paste-Like Substances,” the technical disclosure of which is hereby incorporated by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0003] Not Applicable
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
[0004] Not Applicable
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
[0005] Not Applicable
BACKGROUND OF THE INVENTION
[0006] 1. Technical Field
[0007] The present invention relates to an apparatus and method for dispensing a paste-like substance from a first cavity and can optionally dispense another substance from a second cavity.
[0008] 2. Description of Related Art
[0009] Piston-based dispensing containers are known in the art. For example, Kaplan (U.S. Pat. No. 3,472,423) discloses a compartmentalized dispensing container capable of dispensing a plurality of independently stored substances in such a manner so as to homogenously administer the substances. Nielsen (U.S. Pat. No. 4,323,177) discloses a tube-shaped container with an inner piston. An axial force is provided by a piston rod. Otto, Sr. (U.S. Pat. No. 4,074,833) discloses a tube-shaped container having a conical-shaped end and a conically-shaped piston. A threaded rod is coaxially aligned with the longitudinal axis of the container and through the center of the piston. One end of the threaded rod is secured to a knob, which when turned creates a rotationally-generated axial force that causes a circular member to advance thereby dispensing the contents.
[0010] While the prior art discloses a piston for ejecting a paste-like material from a container, the prior art fails to disclose a container that can be used to store another non-paste like material such as a powdered or granular food topping that can be dispensed separately from the paste material. The prior art also fails to disclose a container that permits a paste to be first dispensed by direct application of an axial force to the piston followed by an axial force generated by rotation.
SUMMARY OF THE INVENTION
[0011] In one aspect, the proposed invention is a container having a first cavity for ejecting a food-based paste and a second cavity for a seasoning. The container comprises a hollow piston having a cone-shaped end and a cylindrical end-cap receiving end. A larger, similarly shaped top section having a cone-shaped section with a dispenser is adapted to encapsulate the cone-shaped portion of the hollow piston. A region of the piston encapsulated between the top section and the cone-shaped portion of the hollow piston defines a first cavity for a paste.
[0012] In one aspect, a recessed endcap having one or more removable sections engages the cylindrical end of the hollow piston defining a second cavity therein. A rotatable piston spinner having one or more openings can be attached to the endcap. Upon removing the removable sections of the endcap, the piston spinner can be rotated to permit or prevent the release of contents from the second cavity. The outer perimeter of the top section can comprise a pair of flange members to facilitate dispensing of the paste that occurs by slidably advancing the piston towards the dispenser. To maximize the amount of paste dispensed from the container, the hollow piston can optionally comprise a set of threads about the outer periphery that are adapted to receive a corresponding set of threads disposed on the inner periphery of the top section once the piston has slidably advanced a pre-determined distance into the top section. The remaining paste is then forced through the dispenser by twisting the engaged threaded sections to rotatably advance the piston. The above as well as additional features and advantages of the present invention will become apparent in the following written detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:
[0014] FIG. 1 is an exploded view of the dual-compartment paste dispensing container in accordance with one embodiment of the present invention;
[0015] FIG. 2 is a cross-sectional side view of the dual-compartment paste dispensing container depicted in FIG. 1 ;
[0016] FIG. 3 is a top perspective view of the dual-compartment paste dispensing container in accordance with one embodiment of the present invention; and
[0017] FIG. 4 is a bottom perspective view of the dual-compartment paste dispensing container depicted in FIG. 3 .
DETAILED DESCRIPTION
[0018] FIG. 1 is an exploded view of the dual-compartment paste dispensing container in accordance with one embodiment of the present invention. As used herein, like numerals indicate like elements throughout the specification. As shown in FIG. 1 , the container comprises a hollow piston 110 comprising a cone-shaped portion 112 that terminates as a plane 119 at the narrow end and a cylindrical section 114 that terminates at a piston flange 111 . In one embodiment, the plane 119 is parallel to the dispenser 128 . In the embodiment shown, the piston 110 comprises male outer threads 115 about the outer periphery of the piston 110 . Similarly, the top section 120 comprises female inner threads 125 designed to threadably engage the male threads 115 . The outer male threads 115 and inner female threads 125 are optional and, in one embodiment, the piston 110 comprises a cylindrical section 114 having no male or female threads. Similarly, in one embodiment, the top section 120 comprises a cylindrical section 124 having no male or female threads. The piston 110 is sized such that the piston 110 can slidably engage the top section 120 and slidably advance the piston 110 towards the dispenser 128 . In the embodiment shown, once the piston 110 has advanced towards the dispenser 128 a pre-determined distance, the piston 110 and top section 120 can threadably engage via the external threads 115 on the piston 110 and the inner threads 125 on the top section 120 . The piston 110 and/or top section 120 can then be twisted to rotatably advance the piston 110 towards the dispenser 128 . As used herein, the term “pre-determined distance” is the length of the cylindrical section 114 from the top external thread 115 to the largest diameter of the cone-shaped portion 112 .
[0019] Similar to the hollow piston 110 , the top section 120 comprises a cone-shaped section 122 and a cylindrical section 124 . In one embodiment, the top section 120 comprises an outwardly extending flange 126 about the circumference near the terminal end of the cylindrical section 124 . The outwardly extending flange 126 can reside anywhere on the cylindrical section 124 of the top section 120 . For example, in the embodiment shown, the outwardly extending flange 126 is located below the inner threads 125 at the terminal end of the cylindrical section 124 . In an alternative embodiment (not shown), the outwardly extending flange is located between the inner threads 125 and the cone-shaped section 122 .
[0020] The cone-shaped section 122 comprises a dispenser 128 at the narrow, terminal end of the top section 120 . In one embodiment, the dispenser 128 comprises one or more spokes 127 . Spokes 127 can be used provide additional rigidity to the dispenser 128 . A snap-fit or threaded removable cap 150 can be used to cover the dispenser 128 . In the embodiment shown, the removable cap 150 is decorative in nature and resembles a lava flow from a volcano. Other decorative or non-decorative caps can be used in other embodiments.
[0021] The endcap 130 comprises one or more scored, removable openings 132 a 132 b . In one embodiment, the endcap 130 comprises an endcap flange 136 about its circumferential periphery, which helps to facilitate the endcap 130 being press-fit into the hollow piston 110 . Consequently, when then endcap 130 is disposed in the hollow piston 110 , the endcap flange 136 mates with the piston flange 111 . A rotatable piston spinner 140 having one or more openings 142 a 142 b can be attached to the endcap 130 . In one embodiment, the piston spinner 140 is snap-fit to the endcap 130 .
[0022] FIG. 2 is a cross-sectional side view of the dual-compartment paste dispensing container depicted in FIG. 1 . The top section 120 slidably engages about the outer periphery 116 of the piston 110 to form a first cavity 210 . The first cavity 210 is defined by the area between the cone-shaped portion 112 of the hollow piston 110 and the top section 120 . The first cavity 210 can be used for storing a paste-like substance. As used herein the terms “paste” and “paste-like substance” are synonymous and are used interchangeably. As used herein, a paste-like substance is used to define materials which have viscosity and flow characteristics which are comparable with those of a non-Newtonian fluid. Examples of paste-like substances include, but not limited to cheese spread, cream cheese, peanut butter, fruit paste, frostings, glazes, and doughs.
[0023] In one embodiment, a second cavity 220 exists in the hollow piston 110 and is defined by the area within the inner periphery 118 of the hollow piston 110 and the endcap 130 . A powdery or granular-like substance including, but not limited to, sugar, ground nuts, decorative sprinkles, herbs, spices, and salt can be placed into the second cavity 220 . Alternatively, a non-granular material can be stored in the second cavity 220 and a user can use the thumb hole 137 to easily remove the endcap 130 and access the material. The material in the second cavity 220 can be any material and is preferably a material that complements the material in the first cavity 210 . For example, peanut butter can be the paste-like material in the first cavity and jelly can be placed in the second cavity 220 . Although many embodiments of the present invention utilize a piston 110 that is hollow, such embodiment is only necessary if a second cavity 220 is desired.
[0024] Referring to FIGS. 1 and 2 , to dispense paste in the first cavity 210 shown in FIG. 2 , a user's thumbs can be placed opposite one another on the endcap flange 136 while the user's index fingers are placed on the top section 120 outwardly extending flange 126 . In this configuration, the operator can then slidably advance the piston 110 towards the dispenser 128 to dispense the paste. As the thumbs and index fingers approach one another as the piston 110 is slidably advanced towards the dispenser 128 , the angle between the index fingers and the thumbs decreases, and it becomes more difficult for the user to provide the requisite force to slidably advance the piston 110 . Consequently, in one embodiment, once the piston 110 has slidably advanced a pre-determined distance, the inner threads 125 can engage the outer threads 115 and the piston can be twisted to rotatably advance the piston 110 towards the dispenser until the cone shaped section 112 of the piston 110 approaches the cone-shaped section 122 of the top section 120 . Such design advantageously dispenses more of the paste-like substance from the first cavity 210 than could be otherwise dispensed without the threads 115 , 125 . In one embodiment, the piston 110 and top section 120 do not have threads.
[0025] FIG. 3 is a top perspective view of the dual-compartment paste dispensing container in accordance with one embodiment of the present invention. FIG. 4 is a bottom perspective view of the dual-compartment paste dispensing container depicted in FIG. 3 . Referring to FIG. 3 and FIG. 4 , in one embodiment, the piston flange 111 comprises an arch 117 to create a thumb hole 137 that allows the consumer to press down on and remove the endcap flange 136 . Such embodiment can facilitate re-fill of the second cavity. In one embodiment, as best depicted by FIG. 4 , the piston spinner 140 can freely rotate in the clockwise or counterclockwise position as shown by the arrows to reveal a removable opening (not visible) on the endcap 130 below. Thus, the piston spinner 140 can be rotated as desired to permit or prevent the release of contents from the second cavity.
[0026] In one embodiment, the present invention comprises a method for dispensing a paste-like substance. To dispense the paste, the dispenser 128 is slidably advanced a pre-determined distance down the cylindrical section 114 of the hollow piston 110 in the direction indicated by the arrows depicted in FIG. 3 . In one embodiment, the internal threads 125 and the external threads 115 are threadably engaged, and the piston 110 and top section 120 are twisted to rotatably advance the piston and dispense additional paste.
[0027] There are several advantages provided by the present invention. One advantage is that the pre-determined distance can be varied as desired. For example, if a relatively high viscosity paste (e.g. a paste that is not easily dispensed) is used in the first cavity, it may only be possible for a person to slidably advance the piston for a short distance. The present invention, however, permits the pre-determined distance that the piston is slidably advanced to be shortened to compensate for this scenario. Thus, in one embodiment, the pre-determined distance can be relatively short and a majority of the piston movement can occur by twisting the top section and piston after the threaded sections have been engaged. Consequently, the present invention can be used to permit people to dispense high viscosity pastes that are resistant to flow. Further, in one embodiment, the pre-determined distance can be adjusted to permit the elderly or young children to better dispense a paste-like substance from a container.
[0028] Another advantage of the present invention is that because there is no axial member within the hollow piston, the hollow piston can be used to as a second cavity to store a granular food topping that can be dispensed separately from the paste material. In one embodiment, the present invention, the first cavity can be used to store a fruit paste and the second cavity can be used to store a colored or uncolored sugar-based topping.
[0029] While this invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. | The present invention discloses a container having a cavity for dispensing a paste and a cavity for another material. In one aspect, a first cavity for a comestible paste resides in an area between a hollow piston and a top section having a dispenser. The top section and piston optionally have corresponding male and female threads in their respective cylindrical sections. The paste can be dispensed by slidably advancing the piston towards the dispenser. In an optional embodiment, the threads can then be engaged to rotatably advance the piston towards the dispenser to dispense additional paste. A comestible seasoning or other material can be disposed in the hollow piston. | 1 |
BACKGROUND
[0001] Exemplary embodiments relate generally to communications services, and more particularly, to methods, systems, and computer program products for implementing an ad-hoc, autonomous communications network.
[0002] Various technologies exist for enabling communications between and among devices, such as telephones, computers, personal digital assistants, and pagers, to name a few. Several communication or transmission protocols have been adopted for facilitating these communications and corresponding network elements. In a wireless networking environment, devices supporting wireless communications typically rely on some type of power source (e.g., battery) that must be periodically recharged in order to maintain operability. In addition, these devices generally require the assistance of a centralized networking system (e.g., host system, cell tower, base station, etc.) to effectuate wireless communications. For example, a telephone number of a target cell phone is entered into a calling cell phone. The call signal is relayed to systems or equipment managed by a service provider which routes the call signal through one or more networks before it is received at the target cell phone.
[0003] There may be situations that occur in which direct, peer-to-peer transmissions (without the aid of an intermediary) are desirable, e.g., a catastrophic event causing a communications network servicing a geographic region to become disabled. Another example is a situation or event occurring in a region that is without adequate communications capabilities (such as a remote area). What is needed is a way to provide direct, peer-to-peer communications among devices without the requirement of an intermediary.
SUMMARY
[0004] The above disadvantages and shortcomings are overcome or alleviated by methods, systems, and computer program products for implementing an ad-hoc, autonomous communications network. Methods include activating a power supply for a first article embedded with communications components. The power supply is generated via at least one of a power source of the communications components and a power generator of the communications components that is implemented via active motion of the first article. The method also includes broadcasting a transmission event via the communications components of the first article for a time period less than or equal to the life of the power supply. The method further includes detecting a communications node within a proximity of the first article, the communications node receiving the transmission event.
[0005] Systems for implementing an ad-hoc, autonomous communications network include a first article embedded with communications components. The communications components include a power supply generated by at least one of a power source of the communications components and a power generator of the communications components that is implemented via active motion of the first article. The communications components also include a transmitter and a transmission event broadcast by the transmitter for a time period less than or equal to the life of the power supply. The communications components further include a means for detecting a communications node within a proximity of the first article, the communications node receiving the transmission event.
[0006] Computer program products for implementing an ad-hoc, autonomous communications network comprise instructions for performing a method. The method includes activating a power supply for a first article embedded with communications components. The power supply is generated via at least one of a power source of the communications components and a power generator of the communications components that is implemented via active motion of the first article. The method also includes broadcasting a transmission event via the first article for a time period less than or equal to the life of the power supply. The method further includes detecting a communications node within a proximity of the first article, the communications node receiving the transmission event.
[0007] Other systems, methods, and/or computer program products according to embodiments will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional systems, methods, and/or computer program products be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.
BRIEF DESCRIPTION OF DRAWINGS
[0008] Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:
[0009] FIG. 1 is block diagram of a system for implementing the ad-hoc, autonomous communications network in exemplary embodiments;
[0010] FIG. 2 is a block diagram of a system for implementing the ad-hoc, autonomous communications network in alternative exemplary embodiments;
[0011] FIG. 3 is a diagram depicting time-sequenced events associated with the generation of power for mobile units implementing the ad-hoc, autonomous communications network; and
[0012] FIG. 4 is a diagram illustrating a sample interaction between three mobile units implementing the ad-hoc, autonomous communications network.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0013] In accordance with exemplary embodiments, the ad-hoc, autonomous networking system enables mobile units to discover and interconnect with communications devices, including other mobile units, within a given proximity. Mobile units refer generally to articles embedded with network elements. The mobile units may be wireless, wireline, or a combination of both. The communications may be enabled using one or more communications and network protocols (e.g., Wireless Fidelity (WiFi), Zigbee protocol, ultra wide band, etc.). Additionally, the mobile units may be auto-powered and self-powered (e.g., as in the case where the mobile unit has a resident power source, such as a battery), creating an ad-hoc networking paradigm that can be perpetuated by movement (e.g., walking motion).
[0014] By enabling mobile units with network connectivity and the ability to discover others within a proximity, an unlimited number of communications networks can be enabled. With relatively little hardware, common items such as shoes, can be enabled with basic components such as power generation, transmission and receiver capabilities sufficient to create a networking node for contacting at least one other such node in the immediately proximity.
[0015] The ad-hoc, autonomous networking system may be implemented for a variety of usages such as entertainment, automatic information collection, and syndromic surveillance as will be described further below. For example, an entertainment application may be a social situation whereby individuals who collectively gather for an event, pass on intangible information ‘droppings’ that are picked up by others (whether acquaintances or not). The information, or transmissions, may be short text messages, light displays, images, music, or similar types of transmissions. Further, the transmissions may be directly targeted to selected mobile units such that only the targeted mobile units are capable of receiving the transmissions, provided they are within range of the broadcasts.
[0016] Automatic information collection refers to specific information collected from mobile units. For example, a venue hosting an event may track participants or attendees at the venue for statistical or marketing purposes.
[0017] Syndromic surveillance refers to specific information collected from mobile units for the purpose of recreating information trails and reconstructing interactions in the course of a time frame. This type of information may be useful in identifying and notifying individuals present at a location in which a contamination event occurred, or for identifying and notifying any individuals who may have been in contact with an individual found to have a contagious disease.
[0018] Turning now to FIG. 1 , a system upon which the ad-hoc, autonomous networking may be implemented in exemplary embodiments will now be described. The system of FIG. 1 includes mobile unit 150 including an article 102 embedded with various elements. The embedded components are collectively referred to as communications components 100 and enable the article 102 to create and maintain an ad-hoc, autonomous communications network. Article 102 may be, e.g., an article of clothing or personal object, and is capable of being transported by an individual or other animate object. By way of example, article 102 is shown in the system diagram of FIG. 1 as a sneaker.
[0019] The communications components 100 embedded within the article 102 include a processor 106 , a receiver(s) 108 , an antenna 110 , a memory 116 , a global positioning system (GPS) transceiver 120 , a receiver antenna 112 , transmitter(s) 114 , and a power generator 124 . Optionally, communications components 100 may also include a rich media generator 126 , power storage 122 , and input/output devices 118 (e.g., sensors, actuators, etc.). Article 102 and communications components 100 collectively form a mobile unit 150 . It will be understood that communications components 100 may be incorporated into other objects as well, such as watches, pedometers, or other wearable, transportable items.
[0020] In accordance with exemplary embodiments, the ad-hoc, autonomous network activities, or a portion thereof, may be implemented via a client application associated with each mobile unit, e.g., a client application executing on processor 106 . Alternatively, a simple logic gate array may be implemented in lieu of the processor 106 for rudimentary networking applications.
[0021] One or more receiver(s) 108 enable mobile unit 150 to receive communications broadcast from other network elements. These communications, both in substance and form, are referred to herein as transmission events. The transmission events broadcast from other network sources are received by receiver 108 via the receiver antenna 112 . Likewise, the transmitter 114 enables the mobile unit 150 to broadcast transmission events to other network devices. Communications components 100 may also include a second antenna 110 for optimizing transmissions between mobile unit 150 and other communications nodes. One or more antennae, including antenna 110 , may be positioned at fixed locations on the article 102 (e.g., front facing, rear-facing, sides) in order to enhance the quality of the communications. Alternatively, one or more antennae, including antenna 110 , may be employed for accommodating signals utilizing various communications protocols (e.g., Bluetooth, ultra wideband, etc.).
[0022] Transmission events may comprise various forms, such as an identifier identifying a broadcasting mobile unit or other mobile unit, a location of the broadcasting mobile unit, a time that the broadcasting mobile unit is at the location, a brand identifier identifying a manufacturer of the broadcasting mobile unit, entertainment content such as lights, text, rich media, and audio elements.
[0023] The global positioning system (GPS) 120 transceiver enables the mobile unit 150 to track its location as it travels from one area to the next by sending signals to, and receiving signals from, a GPS network. The memory 116 may be a temporary storage element that holds data for a limited period of time. Alternatively, a non-volatile storage element (e.g., flash memory) may be employed to maintain information elements. Memory 116 may store items such as the identifier of the mobile unit 150 , the location derived from GPS transceiver 120 , distance measured while traveling, and logs of statistical data (e.g., location information and time).
[0024] Power generator 124 provides the energy required to enable communications or transmission events, as well as implement other items comprising communications elements 100 . In accordance with exemplary embodiments, power generator 124 is mechanically charged and may be recharged as needed. Power generator 124 may be implemented in various ways. For example, power generator 124 may be implemented using a weight-driven (e.g., eccentric weight) mechanism. Alternatively, power generator 124 may be implemented using a solar cell incorporated, e.g., into the article 102 , along with a small rechargeable battery or capacitor for allowing short power retention. Alternatively, a piezoelectric deformable element may be incorporated into the article 102 that generates small voltages with each movement or step or emits a fast series of pulses with each step (e.g., ultra wideband emission). In this embodiment, the article 102 may be designed with a piezo element that is disposed between compressible and non-compressible elements, such that each step would cause the compressible and non-compressible elements to bear down on the piezo element, thus emitting a charge.
[0025] In alternative exemplary embodiments, a power source (e.g., a battery) may be included in the communications components 100 for supplying power to the article 102 . The mechanically produced power described above may then be used for recharging the power source when needed.
[0026] As shown in the system diagram of FIG. 1 , communications elements may alternatively include a rich media generator 126 , power storage 122 , and input/output elements 118 . The rich media generator 126 may comprise, e.g., digital camera or image capture equipment. An image may be captured via the rich media generator 126 and broadcast to other communications devices or mobile units. Power storage 122 enables mobile unit 150 to temporarily store power that was generated by power generator 124 . Power storage 122 may comprise, for example, ultra capacitors capable of rapidly storing instantaneous charge spikes, or other suitable devices. Input/output elements 118 allow an individual to control the transmission events broadcast to others and to perceive the incoming transmission events. For example, an input element may be provided that allows an individual to select or target a recipient mobile unit for receiving a transmission event. The individual may further select a response activity that is implemented in response to a transmission event (e.g., flash blue lights on sneaker when desired target receives transmission event or is in broadcast proximity). The input/output elements 118 may include some type of display for receiving transmission events in text form, or a speaker for presenting transmission events in audio form, etc.
[0027] In exemplary embodiments, mobile unit 150 is in communication with a communications node 104 as shown in the system diagram of FIG. 1 . Communications node 104 may be another mobile unit, a telephone, cell phone, pager, personal digital assistant, server, or other communications device.
[0028] Turning now to FIG. 2 , a system for implementing ad-hoc, autonomous networking activities in alternative exemplary embodiments will now be described. The system of FIG. 2 incorporates many of the same or similar elements as those described above with respect to FIG. 1 . Unless indicated otherwise, the elements shown and described in FIG. 2 perform substantially the same functions as those described above in FIG. 1 . The system of FIG. 2 includes an aggregator 230 in communication with a network 232 . Alternatively, aggregator 230 may be directly in communication with mobile unit 150 . Aggregator 230 collects information broadcast from mobile units such as mobile unit 150 and may be implemented by a server, personal computer, or other suitable processor device.
[0029] As indicated above, there may be various uses for the ad-hoc networking system, including entertainment, automatic information collection, and syndromic surveillance. Aggregator 230 may gather the information directly from mobile unit 150 if within proximity of mobile unit 150 . Alternatively, aggregator 230 may collect information indirectly from mobile unit 150 , e.g., through communications node 104 and network 232 . In alternative embodiments, aggregator 230 may comprise a mobile unit configured with advanced features (e.g., additional memory, advanced power generator, etc.) for collecting greater quantities of information from other mobile units.
[0030] Turning now to FIG. 3 , a diagram illustrating a sampling of time-sequenced power generation events will now be described in exemplary embodiments. The diagram of FIG. 3 displays five time periods (T 1 -T 5 ) through which a mobile unit is mechanically generating power. At each time period, the diagram of FIG. 3 illustrates a corresponding power output, storage capacitance, activity, and state items relating to the mobile unit. The mobile unit may be in one of three power states: dead, alive, and dying. As can be seen from FIG. 3 , prior to T 1 , the mobile unit is in a dead state. During T 1 , the motion of the mobile unit (MECHANICAL GENERATOR EVENTS) causes the power generator to generate power (INSTANTANEOUS POWER OUTPUT). The power increases and decreases in proportion to the extent of movement. At T 1 , the storage capacitance also increases and decreases in proportion to the extent of movement (USABLE POWER CAPACITY). As shown in FIG. 3 , during the period of T 1 when the mobile unit has power, it is able to broadcast or receive a transmission event (ACTIVITY). The corresponding state of the mobile unit at this time is ALIVE. Between T 1 and T 2 , there are no mechanical generator events occurring and there is no power output. Accordingly, the state of the mobile unit at this time is DEAD, which means the mobile unit is unable to broadcast or receive transmission events. However, this does not necessarily mean that all previously transmitted and received information is gone. The information may ‘live on’, e.g., through passing the information on to other mobile units (i.e., as from one broadcast to the next or from one transmission event to the next) referred to herein as stigmergy. Alternatively, if the mobile unit 150 includes non-volatile memory, the information may be accrued over time and stored in the non-volatile memory and so may likewise ‘live on’ even when the power state of the mobile unit 150 is DEAD. It will be understood that mobile units 150 may be configured such that some have non-volatile memory incorporated therein while others have temporary storage capabilities.
[0031] Moving forward to the time periods of T 2 and T 3 , the rate of mechanical generator events has diminished, although not halted, and the power output is weakening. At this time, the state of the mobile unit is DYING, which means that the mobile unit has limited ability to broadcast or receive transmission events. As shown in time periods T 4 -T 5 , the rate of the mechanical generator events increases resulting in greater power output. With optimized power output capabilities, the mobile unit may be capable of performing other functions in addition to broadcasting and receiving transmission events. For example, the mobile unit may seek out a GPS location status, collect and log information elements produced from recently received transmission events, send transmission events that require more substantial power (e.g., image capture and transmission), etc.
[0032] Turning now to FIG. 4 , a diagram depicting a stigmergic application of ad-hoc, autonomous networking (e.g., syndromic surveillance) will now be described in accordance with exemplary embodiments. The diagram of FIG. 4 illustrates two regional quadrants (QA and QB) and three mobile units 402 , 404 , and 406 . Though quadrants are shown in FIG. 4 for ease of illustration, it should be appreciated that the invention is applicable to any arrangement of geographic regions. Each of quadrants QA and QB represent a geographic region whereby mobile units present in the quadrants are discoverable by one another. Likewise, a mobile unit in one quadrant may not be discoverable by a mobile unit in the other quadrant. Each of mobile units 402 , 404 , and 406 follow a unique pathway, periodically broadcasting a transmission event 408 . When mobile unit 402 enters quadrant QB, it sends out a broadcast (TE 1 ), which goes undiscovered. On the second broadcast in quadrant QB, it discovers mobile unit 404 , which receives the transmission event (TE 1 ) and sends out its own transmission event (TE 2 ). The transmission event (TE 1 ) may be temporarily stored by mobile unit 404 . Subsequently, mobile unit 404 enters quadrant QB. In its second broadcast in quadrant QB, it discovers mobile unit 406 , and sends out transmission event (TE 2 ) and may further send all or a portion of TE 1 captured from mobile unit 402 . Mobile unit 406 then continues along its pathway. By passing along transmission information from one mobile unit to the next in a stigmergic fashion, the transmission information may be sustained indefinitely, even when the information is purged from the temporary storage previous mobile units. Acquiring this information can be useful in retracing events and individual contacts for conducting syndromic surveillance or other applications.
[0033] As indicated above, the ad-hoc, autonomous networking system enables mobile units to be in direct contact with communications devices or other mobile units within a given proximity. The mobile units may be wireless, wireline, or a combination of both. The information or transmissions may serve a variety of purposes, such as entertainment, social interaction, information collection, or syndromic surveillance. Additionally, the mobile units may be continuously charged and self-powered by mechanical means.
[0034] As described above, the present invention can be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into an executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.
[0035] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. | Methods, systems, and computer program products for implementing an ad-hoc, autonomous communications network is provided. The method includes activating a power supply for a first article embedded with communications components. The power supply is generated by at least one of a power source of the communications components and a power generator of the communications components that is implemented via active motion of the first article. The method also includes broadcasting a transmission event via the first article for a time period less than or equal to the life of the power supply. The method further includes detecting a communications node within a proximity of the first article, the communications node receiving the transmission event. | 8 |
TECHNICAL FIELD
The invention relates to a paint drying system for painted bodies, and particularly, but not exclusively, a system for drying painted motor vehicles.
BACKGROUND ART
Conventional automobile spraybooths dry solvent-borne paints which have been applied onto the surfaces of a motor vehicle by passing heated air over the painted surface. Typically, heated air is blown into the spraybooth through inlets e.g. in the booth ceiling and is evacuated through floor outlets.
The surfaces of the bodies such as motor vehicles and particularly non-conductive components such as plastic bumpers, are normally found to be electro-statically charged. This electrostatic charge results from normal handling of the body prior to painting and is generally unavoidable.
The electrostatically charged surfaces of the vehicle attract dirt and dust particles and this results in contamination of the painted surface.
In an attempt to reduce such contamination, the surface is typically degreased and “tacked off” (rubbed using what is commonly referred to as a “tack rag”) prior to painting. However, this can be counter-productive as the rubbing action greatly increases the static charge on the surface. Loose/airborne particles originating from tack cloths, operator clothing etc., are then attracted to the surface.
Paint is typically applied to motor vehicles using a spray gun. When the paint is atomised from the spray gun, this also acquires a static charge which attracts dirt and dust particles.
The result is that the painted surface is often contaminated by dust/dirt particles and although the painting process is designed for a “gun finish” without subsequent polishing, refinishing work is often necessary involving many wasted hours of removing dirt ingressed during painting which reduces the cost effectiveness of the painting operation.
A further problem is that metallic paint finishes make up approximately 50% of car colours currently on the road. Mica or aluminium is used to produce the metallic finish and is disturbed by static charge which can result in a patchy surface and colour inaccuracy.
DISCLOSURE OF THE INVENTION
It is, therefore, an object of this invention to provide a system for drying a painted body which eliminates or, at least, reduces contamination by dust and particles of the painted surface, thereby eliminating or, at least, reducing the need for refinishing operations.
According to the invention therefore there is provided a paint drying system for drying a painted body, the system comprising a spraybooth having an enclosure, an air inlet, an air outlet and means to supply air to the inlet to flow through the enclosure from the inlet to the outlet, characterised by the provision of means for electrically charging the said air supply.
With this arrangement any static charge on the body surfaces or on particles present on the surfaces is neutralised by ions in the air supplied, thereby eliminating or, at least reducing contamination of painted surfaces and eliminates or reduces the need for refinishing operations which would otherwise reduce the cost effectiveness of the operation.
A further, somewhat surprising effect, which has been noted is a reduction by 20% in drying times of painted motor vehicles.
Furthermore, it has been found that dust and dirt particles are predominantly positively charged.
Thus, preferably the supply air is negatively charged. The negative ions produced neutralise any positively charged particles present on the panel thereby neutralising the attractive forces between the charged contaminants and the panel so that the contaminants are then easily blown off the surface by the air flow through the booth and subsequently removed via the air outlet.
However, it is not intended that the invention is to be restricted to the negative ionisation, and it is envisaged that positive ionisation may be provided, if desired, for example, to neutralise contaminants found to be negatively charged.
The means for electrically charging the air inlet supply to the enclosure may take any suitable form however and this preferably comprises at least one ionisation member operable to be electrically charged by, for example, appropriate electrical coupling to a voltage supply.
The each ionisation member preferably comprises a conductive material e.g. metal.
Alternative forms of air charging means may be used, however, the advantage of using a high voltage charging device is that this type of device is not regulated by stringent legislation and is fairly easy and inexpensive to obtain. Furthermore, a high voltage charging device can be safely used whilst operators are inside the enclosure.
The spraybooth may take any suitable form but, preferably, the means to supply air to the inlet comprises a pump/pumps, which preferably are operable to supply air from the atmosphere externally of the booth to the air inlet. Preferably, also the spraybooth incorporates a heater for heating the inlet air.
Alternatively, air may be re-circulated from within the enclosure, or from a plenum chamber of the inlet or outlet air system.
The air inlet may take any suitable form and may include a duct/duct system which is connected to the enclosure at one or more openings in the enclosure walls or ceilings etc. so as to supply air into the enclosure.
The spraybooth may have at least one further air inlet which may receive air from the atmosphere externally of the booth and direct this air into the enclosure transversely of the said airflow.
Alternatively, this air may be re-circulated from the enclosure to the further air inlet.
This air inlet may comprise air nozzles or jets which are mounted internally of the enclosure and are operable to direct air obliquely at surfaces of the body.
The air nozzles/jets may be mounted on a housing or support structure which is mounted internally of the enclosure.
Compressed air may be supplied to the air inlet and/or the further air inlet by means of an air compression device.
The or each ionisation member may be located in any suitable position. However, preferably the or each ionisation member is mounted internally of the enclosure and particularly, preferably, directly in the path of the air flow into the enclosure, from the air inlet and/or the further air inlet.
To this end, the ionisation member may be mounted on an internal structure of the enclosure e.g. wall, ceiling, etc., and preferably adjacent e.g., so as to straddle the or each enclosure opening.
With this arrangement, ions produced by the or each ionisation member may be distributed to the body surfaces by the said air flow (from the inlet).
However, the invention is not intended to be restricted to mounting of the ionisation member within the enclosure. Alternatively, the ionisation member may be located at any suitable position within the air inlet and/or the further air inlet.
Where the spraybooth incorporates a further air inlet, as mentioned above, the or each or any ionisation member may be attached to, or adjacent, the further air inlet, so as to position the member directly in the path or the air flow from the nozzles/jets into the enclosure. Alternatively, there may be one or more ionisation members within or adjacent each jet or nozzle.
The or each further air inlet may include doors which, in a closed position, are operable to shield or enclose the nozzles or jets when not in use e.g. during painting so as to prevent contamination of the nozzles/jets by airborne paint particles.
The or each ionisation member may be located so as to be shielded or enclosed by the doors when in a closed position.
The or each ionisation member may be mounted so as to be positionally adjustable.
The or each ionisation member may have any suitable structure, and may be an elongate bar or rod or a grid/grill structure.
Preferably, the or each further air inlet comprises one or more parallel columns of nozzles/jets and there is one ionisation member consisting an elongate metal rod which is mounted generally parallel with the said columns.
The ionisation member may be integral to the spraybooth so that part of the spraybooth is electrically charged.
Advantageously, the paint drying system may also be used for drying a body painted with a water-based paint.
The body may be any suitable body, but preferably, it is a motor vehicle.
A further problem concerns a control system for controlling a paint drying system.
Conventional automobile paint drying systems comprise a spraybooth in which the motor vehicle body is first painted and then dried (or ‘baked’). The temperature at which the painted body must be dried and the drying time is critically dependent upon the type of paint which has been applied and the paint surface finish required.
Spraybooth drying times are generally the most important factor within a busy paint spraying workshop. Each paint product has optimum drying temperature time (collectively referred to as a drying cycle) both in terms of speed and quality. The same applies to paint manufacturers as a paint product as one company may benefit from different temperature profile to that of another manufacturer.
Spraybooth operator errors in setting the temperature and time of the drying process can mean that the paint is not dried sufficiently, and in this case, the drying process must be repeated in its entirety. Such errors may expensively reduce the number of painted bodies which may be dried and so reduce the cost effectiveness of the paint drying operation.
A further object of the present invention is to provide a control system which eliminates or reduces operator error.
According to a further aspect the invention therefore, there is provided a control system for controlling a paint drying system for drying a painted body, the control system including at least one user-operable control, the or each user operable control being operable to preselect a predetermined parameter or predetermined combination of parameters.
With this arrangement the paint drying system can be operated in a quick and efficient manner, increasing the throughput of the paint drying system and, at the same time because individual setting of the various system parameters is not necessary, there is less risk of user error when operating the paint drying system.
The painted body is preferably a motor vehicle, e.g. a motor car. However the invention may also advantageously used for drying other painted bodies such as aircraft bodies, watercraft bodies etc.
The paint drying system may include a spraybooth which may have an enclosure in which the painted body is dried. The spraybooth may have an air inlet and air outlet, and pump means to supply air from atmosphere externally of the spraybooth to the air inlet to flow through the enclosure from the air inlet to the air outlet. Preferably, the spray booth incorporates a heater for heating the inlet air.
The or each user-operable control may be operable to preselect a single predetermined parameter, such as temperature.
However, the or each user-operable control may be operable to control any number and combination of system parameters, such as inlet air flow rate, temperature, pressure, humidity, spraybooth enclosure temperature, pressure, humidity, etc.
The control system may incorporate sensors for sensing paint drying system operating parameter values, such a enclosure temperature, pressure, inlet flow rate etc., so that such parameter values can be monitored and regulated by the control system.
Preferably, the or each user-operable control is operable to preselect at least two predetermined parameters, wherein one of such parameters is a time and/or temperature related parameter.
Most preferably, the or each user-operable control is operable to control the characteristics of a respective drying stage or cycle in which a parameter such a temperature, or combination of parameters vary with time.
The spraybooth may have at least one further air inlet which receives air from the atmosphere externally of the booth and directs this air into the enclosure transversely to said air flow.
This air inlet may comprise air nozzles or jets which are mounted internally of the enclosure and are operable to direct air obliquely at surfaces of the motor vehicle.
Accordingly, the user-operable control may be operable to preselect system parameters associated with the further air inlet airflow, such as air flow rate, temperature, pressure, humidity etc.
The predetermined parameters which are preselected by the or each user-operable control may vary with respect to time, such that the parameter values vary during a particular drying stage or cycle. For instance, a parameter may increase/decrease incrementally throughout the drying cycle or part of the cycle, or there may be one or more ramped increase/decrease(s) during a cycle.
In a preferred embodiment there are a plurality of user-operable controls, each control being operable to preselect the parameters of an associated drying cycle, such that a plurality of drying cycles may be provided for.
The or each user operable control may take any suitable form and may comprise a button, key, switch, touch/heat/photo-sensitive display screen etc.
Preferably, the control system incorporates an electronic control unit such as programmable controller or a microprocessor based unit and may further incorporate a data storage (memory) unit so that the parameter values may be stored.
Preferably the control unit is pre-programmable so that the system parameters for the or each drying cycle of the system may be pre-programmed, by , for example, the spraybooth proprietor, or manufacturer.
Accordingly, the control unit may include a data entry device such as a keypad or keyboard and further preferably a date entry display device to enable viewing of entered programming data during and/or after pre-programming.
The control system may incorporate a display device to display the parameter settings of a particular drying cycle. This display device may be operative to display the parameter settings either on demand and/or during a drying cycle.
The or each display may comprise any suitable form but preferably incorporates a digital display. There may be a separate display for each of the above functions or alternatively, and preferably there is a single, multi-functional display device operative to display parameter values during pre-programming and during a drying cycle.
Preferably, the control system includes a housing which houses the above described control system components. The housing may take any suitable form such as a metal or plastic box construction.
The housing may be attached or integral to the spraybooth, but preferably, it provides for electrical/pneumatic/hydraulic coupling of the control system to corresponding spraybooth components as is required e.g. an electric coupling between the or each heater, a spraybooth thermo-sensor and the control housing for effecting enclosure temperature control; a pneumatic coupling between a pressure sensor in the enclosure interior and the control housing and any of the spraybooth flow rate devices (pumps, fans, flow dampers etc.) for effecting control of the pressure of the enclosure etc.
Preferably, the user operable components of the control system including the user operable control(s), data entry device(s) and any display device(s) alarms etc., are mounted so as to be accessible by a user/operator when outside of the enclosure.
Advantageously, these user operable components mentioned above are mounted on a panel which may be incorporated into the above described housing.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described by way of example and with reference to the accompany drawings in which:
FIG. 1 is a diagrammatic representation of part of a paint drying system according to one form of the present invention, showing an ionisation member.
FIG. 2 is a plan view of the ionisation member of FIG. 1
FIG. 3 is a plan view of the paint drying system of FIG. 1
FIG. 4 is a perspective view of the paint drying system of FIG. 1 .
FIG. 5 is a diagrammatic representation of a control system of the present invention;
FIGS. 6 a - 6 h are typical temperature profiles of drying cycles of the paint drying system of FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, a paint drying system is used for drying a painter motor car.
The paint drying system comprises a spraybooth 1 which has an enclosure 2 of generally rectangular box construction in which the vehicle 4 (only shown in FIG. 3) is first painted and then dried and/or baked.
The spraybooth 1 incorporates an air inlet system 6 and an air outlet system 8 such that air flows under the action of pumps 10 , from the atmosphere, externally of the spraybooth 1 , into the enclosure 2 . The air inlet system 6 incorporates ducting 26 and a plenum chamber 28 through which inlet air passes to the enclosure 2 .
The spraybooth 1 has a re-circulation duct 12 which connects the inlet and outlet ducts (by means of a damper) during baking of the painted vehicle so as to provide re-circulation of 90% of spraybooth air—thereby increasing the temperature of the enclosure during baking. This air flow is enhanced by a number of pumps and fans.
The air inlet further incorporates a gas-fired air heater 14 for preheating the inlet air. (Alternatively, this could be an oil-fired heater).
The air outlet of the spraybooth comprises a grid 16 in the enclosure base which leads via ducting 18 to the atmosphere external of the booth. This duct incorporates an air flow damper (not shown) which can be closed to restrict air flow from the enclosure. If air flow into the chamber is maintained whilst the damper is in the closed position, the internal pressure of the enclosure increases above atmospheric pressure. Similarly, when the damper is in the open position, the enclosure may be negatively pressurised by adjusting the flow rate of air into the booth.
The spraybooth incorporates main doors 20 for vehicular access and operator access doors 22 .
The system incorporates a control system (described in detail hereinbelow) which is operable to remotely control the parameters: time, temperature and pressure of the various (eight) drying cycles (in which all the air flowing through the enclosure is from the atmosphere, externally of the booth) and the bake cycle (in which the air is re-circulated as described above).
The spraybooth 1 incorporates a further air inlet comprising four corner units 30 , the unit 30 being mounted internally of the enclosure 2 in the respective four corners thereof.
Each unit 30 has a triangular body in the form of an elongate shell of triangular cross section mounted upright in a corresponding enclosure corner unit 30 .
Each unit 30 has an internal passageway 32 which is connected to the air inlet system ducting 26 , and has two columns of four spaced apart vertically aligned air jets 34 which are directed obliquely at the surfaces of the car 4 . (As shown in FIG. 3 ). The two lowermost jets are 300 mm from the base of the enclosure and the distance between adjacent vertically aligned jets is 300 mm.
Each corner unit 30 has a door 31 which can be pneumatically and remotely operated between an open position as shown, and a closed position in which the air jets 34 are enclosed (for use during paint spraying operations).
The further air inlet also incorporates four ionisation members 33 each comprising an elongate metal rod 1100 mm in length and which is electrically coupled to a high voltage supply consisting of an AC power unit (not shown), controlled by an electrical control unit (not shown) and coupled to a coil which is connected to the bars 33 by high tension leads (not shown). The control unit is integrated into the spraybooth control system (not shown) so that operation of the ionisation member can be remotely controlled.
The ionisation members 33 are mounted upright on the corner units in between the two columns of air jets 34 .
The ionisation members 33 are operable to emit ions within a range of approximately 100 mm (in static air conditions).
The ionisation members 33 are mounted so that, as with the jets 34 , they are exposed with doors 31 open and enclosed with the doors 31 shut.
Dual speed motors (alternatively air volume dampers) are fitted to the corner units to reduce the velocity of the air flowing through the jets on the bake cycle—high air velocities can damage the wet paint finish.
In use the doors 31 are open and the heated air is pumped to flow from the atmosphere externally of the booth, through the air inlet ducting 26 (and plenum chamber 28 ) into an inlet in the ceiling of the enclosure 2 and to the corner mounted jets 34 .
The air from the jets enters the enclosure transversely to the air entering via the ceiling, and directs the air obliquely at the external surfaces of the painted motor vehicle.
The ionised bars 33 are then electrically charged to negatively charge air flowing into the chamber from the air jets. (opening of the doors is a control system requirement for charging of the bars 33 ).
The air flow distributes the ions on to the surfaces of the motor vehicle thereby neutralising any positively charged dirt/dust on the surfaces. Statically neutralised, the dirt and dust is no longer attracted to the surfaces and blown away and extracted via the outlet system.
Paint is generally applied to a motor vehicle in a number of layers. Advantageously the anti-static ionisation bars 33 are used throughout the process i.e. during initial preparation prior to painting of the vehicle within the spraybooth and a primer paint baking cycle, during a waterborne paint drying cycle and on a final laquer coat or solid colour baking cycle.
This ensures that static charge is continuously neutralised for quality of finish and cleanliness but also the process baking times are, surprisingly, reduced by approximately 20%.
The corner unit with ionisation bars may, together, with a modified control system, be retrofitted into existing e.g. standard downdraft spraybooths.
The above paint drying system provides an automated statically neutralised paint drying system for the motor vehicle refinishing industry. This eliminates the need for refinishing after drying.
Referring to FIG. 5, the control system 210 is used to control a paint drying system is used for drying a painted motor car. The paint drying system comprises a spraybooth 1 which has an enclosure 2 of generally rectangular box construction in which the vehicle (not shown) is first painted and then dried and/or baked.
The control system comprises a housing 212 which is a metal rectangular box construction and is secured to one of the upright external walls of the enclosure so as to be accessible to an operator when he/she is outside of the enclosure. The housing incorporates a front panel 213 hinged to the housing by hinges 213 a and 213 b . This panel 213 conveniently locates all user-operable components and display devices as described below.
The housing incorporates a ‘bake mode’ electronic temperature control device 214 comprising an digital programmable controller with a data storage device (not shown), four digital display screens 216 , 218 , 220 , 222 and a data-entry keypad 224 .
A thermocouple (not shown) is installed in the spraybooth enclosure and is operable to measure the temperature of the enclosure and connected to the device (the connection being indicated by the dashed line 226 ) so as to transmit temperature readings to the controller. The controller 214 is also connected to the heater so as to be operable to control the heater. The device is thereby, by means of a simple closed loop control system operable to control the temperature of the enclosure.
The housing also incorporates a second simplified ‘spray mode’ temperature controller 228 which is constructed as for the ‘bake mode’ controller, with similar connections (indicated by dashed line 229 ) to heating devices as described for the ‘bake mode’ controller above, excepting it has a single display 230 and a simplified keypad 232 .
The housing incorporates eight user-operable control push-buttons 234 . Each of the buttons 234 is connected to input terminals of the temperature controller via relay switches so that when activated, each button connects to a respective pair of bake controller input terminals so that each button can provide a different input signal to the controller. Each button is identified by the controller by a respective one of numbers 0-7. The buttons 234 each include a respective lamp which illuminates when the button 234 is depressed.
The control housing also incorporates other standard control buttons: an on/off button 239 connects the internal circuitry of the control housing to the mains power supply; a reset button 240 is operative to cancel the previous selection of user-operable control button; bake mode start and stop buttons 242 and 244 start and stop the selected drying process; spray mode start and stop buttons 246 and 248 start and stop the spraying process. There is also an enclosure lighting controller button 250 and a heater alarm 252 which can be used to shut off the gas heaters of the air input (or oil-fired heaters as the case may be).
The control system also includes pressure regulatory controllers. A pressure balance controller button 254 is connected to the air outlet damper so that the spraybooth enclosure pressure can be positively or negatively pressurised. A over pressure control 256 is operable to shut the entire paint drying system down if the pressure inside the booth exceeds a set level. Both controls 254 and 256 are connected to an enclosure pressure sensing device (not shown) mounted in the spraybooth enclosure interior, and this is also connected to a pressure gauge 258 which displays current operating pressure within the enclosure.
All button except those referenced 239 , 250 , 252 , 254 and 256 are push buttons.
The ‘bake mode’ controller is used to control the time and temperature parameters of eight different drying cycles, each one having an associated user-operable controller button 234 . An example of a predetermined selection of drying cycles is as follows:
1. primer—Hi build/surfacer
2. wet on wet primer
3. clear coat standard
4. clear coat express
5. solid colour standard
6. solid colour express
7. 80 deg. C for 30 minutes—Airtemp (metal)
8. 60 deg. C for 30 minutes—Airtemp (plastic)
The unit is pre-programmed by inputting the time/temperature values of each drying cycle into the memory unit via the keypad 224 . During pre-programming of each drying cycle, the input values are displayed in the display regions 216 - 222 . However, once the programming is completed the keypad may be electronically locked to prevent tampering.
Each drying cycle comprises a predetermined number of timed temperature phases or steps so that the temperature profile of the drying system changes with respect to time for each cycle (as shown more clearly in FIGS. 6 a - 6 h ).
The step number, step duration, associated enclosure temperature setting of each step are displayed in respective display regions 218 , 220 and 222 .
The number of the associated user-operable button 234 is also displayed in the display region 216 .
The ‘spray mode’ temperature controller is used to control the temperature within the enclosure during spraying. The temperature is set by pre-programming the controller 228
The example temperature profile graph of FIGS. 6 a - 6 h shows a typical programme. The less sensitive products benefit from a rapid temperature rise whilst others require a slower temperature increase initially but higher temperatures towards the end of the cycle.
Standard bake time and temperature combinations are included with buttons 7 and 8 for non standard products.
Having the most efficient cure cycle saves valuable booth time and energy consumption.
The quality of cure reduces the risk of paint defects and warranty problems.
In use, the motor vehicle body is first sprayed. The operator simply presses the ‘spray mode’ start button 246 which initiates the spray process at the pre-programmed temperature (in this case 21 degrees centigrade). The operator then begins spraying.
When the spraying process is complete, the paint drying system is activated by pressing the user-operable control appropriate to the paint and finish required. The button is thereby illuminated and its identifying number indicated in display region 216 .
Each step in the selected drying cycle is also shown in display regions 218 - 222 : i.e. as shown in the FIG. 1, activated and illuminated button 234 a is identified as button ‘ 0 ’ in display region 216 ; the current step is identified as step ‘ 1 ’ in region 218 ; the enclosure temperature of this step is identified as 25 degrees centigrade in display region 220 and the step number identified in display region 222 .
The operator then depresses the ‘bake mode’ start button and the drying cycle is initiated. The operator has no need to select individual temperature parameters, which are particularly critical to the paint finish obtainable.
With this arrangement, the paint drying system can be operated in a quick and efficient manner, increasing the throughput of the paint drying system and, at the same time because individual setting of the various system parameters is not necessary, there is less risk of user error when. operating the paint drying system.
It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only. | A paint drying system for drying a painted body ( 4 ), such as a painted motor vehicle, includes a spraybooth ( 1 ) having an enclosure ( 2 ) through which air flows from an air inlet ( 6 ) to an air outlet ( 16, 18 ). The spraybooth ( 1 ) may also have columns of air jets ( 34 ) mounted in respective corners of the enclosure ( 2 ) to direct air obliquely at surfaces of the vehicle body ( 4 ). The system includes ionization members ( 33 ) for electrically charging this air supply. In a preferred embodiment the air is negatively charged by ionization members comprising one or elongate rods ( 33 ) mounted parallel with the columns of air jets ( 34 ). The spraybooth ( 2 ) may also have a control system ( 210 ) for controlling the paint drying system ( 4 ). The control system ( 210 ) has user-operable controls ( 234 ) to pre-select a predetermined parameter/combination of parameters and thus control the characteristics of a respective drying stage or cycle which parameters, e.g. temperature, vary with time. | 8 |
This application is a continuation of application Ser. No. 07/835,230, filed Feb. 13, 1992 now abandoned.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to acoustics and more specifically to sound barrier structures.
2. Prior Art
Sound barrier walls typically used along highways have flat surfaces which simply reflect noise with limited change. Sound barriers with three dimensional surfaces have greater potential for controlling noise. Complex baffle and resonator structures for example are well-known in acoustic chamber applications. Several U.S. patents disclosing sound barriers are reviewed in Applicant's co-pending application Ser. No. 07/705,587, now abandoned, which is incorporated herein by reference.
Referring to FIG. 1, a conventional Helmholtz resonator R has a hollow cavity C of volume V mostly surrounded by inside surface S of enclosure E. Interior cavity C communicates by a proportionally dimensioned port P through an opening of diameter D and length L on axis T to the exterior of enclosure E.
Acoustic resonators R are conventionally molded around a given volume V defined by a convex outside surface of a rigid solid interior form (not shown).
Conventionally, molding media mass is supported around rigid forms. After molding a medium outside, any solid rigid forms left inside need to be removed to embody a resonator R. Interior form removal may be possible only in pieces through a port compromised to a larger than preferred diameter D.
Cavity volumes V can as well be defined on the exterior of a molding medium using rigid forms with concave inside surfaces. If external pressures can be neglected or controlled during molding, then a cavity C interior does not need support by a form.
For example, in blow molding, a fluid (e.g., air) pressure on an inside surface of a sheet of plastic overcomes a lower pressure on its outside surface of the plastic confronted by a rigid exterior form. Biased pressures on the sheet plastic distends outward to, and through a port hole entrance into, the form. A resonator cavity opening inflates inside to conform the plastic surface to bulb molding surfaces on the inside of the rigid form.
Obstacles such as these constrain the economy of using acoustic resonators more widely as noise barriers. Thus, there remains a need for improved techniques of constructing sound barriers.
SUMMARY OF THE INVENTION
A primary object of the invention is to provide an efficient means for attenuating sound. Another object is to provide durable and weather resistant means for suppressing noise. A further object is to provide large area panels for noise-barriers. An additional object is to mold resonators without using solid forms inside cavities.
Acoustic resonator panels according to the invention are preferably embodied through two stages of molding. A first stage pre-forms resonator bulbs without having solid forms inside. In a second stage, the pre-formed resonator bulbs and concrete are molded together to form a sound-attenuating panel.
The invention's advantages are made increasingly apparent in the following Detailed Description and accompanying Drawing.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 illustrates a Helmholtz resonator;
FIG. 2 is an isometric view of a jig form which defines a panel molding region for holding pre-formed resonator bulbs in a pattern with intervening spaces to be filled by concrete;
FIG. 3 shows a pre-formed bulb at a resonator location on axis T3 in a cross-section along plane 3--3 through the jig form of FIG. 2;
FIG. 4 is an isometric view of a resonator panel having a sound-receiving front face with port openings molded by pre-formed resonator bulbs; and
FIG. 5 is a view along arrow 45 in FIG. 4 with a resonator opening on axis T5 through cross-section plane 5--5.
DETAILED DESCRIPTION OF THE INVENTION
The present invention forms sound-attenuating panels by molding a medium such as concrete around acoustic resonators. In a first stage a Helmholtz resonator is pre-formed as a bulb enclosing a volume of space without using a solid rigid form. The hollow bulb material may be formed through mechanical, thermal, chemical, electrolytic, magnetic or other applicable instrumentalities. A plastically-moldable medium of, for example, metal, glass or polymer plastic can be blow-molded or roto-molded into a bulb using a rigid form on only the exterior of the bulb.
Preferably, resonator bulbs are blow-molded by fluid (e.g., air) pressures unbalanced on inside and outside surfaces of a thin moldable sheet of plastic. Pressure biased outward on the sheet distends plastic toward and into an entrance hole to a passage within, a rigid exterior form. Plastic flows along the passage surrounded by a cylindrical port-form molding surface. The passage opens into a bulb cavity-form space surrounded by a bulb cavity-form molding surface. The molding surfaces anticipate the shape of concrete to be molded around molding surfaces on the outside the bulb later as shown in FIG. 5.
Pressure inflates the plastic and spreads its surface through the form space. The resonator opening expands until plastic fills the form space entirely to the molding surfaces. The resonator opening inside surface conforms within a tolerance to the contour of the molding surfaces. While conforming, the plastic hardens and its shape is fixed as a bulb.
Afterwards the rigid exterior form is removed. This leaves the plastic resonator bulb, ending the first stage. Completed resonator bulbs may resemble light bulbs or Christmas tree ornaments as well as the resonator schematic in FIG. 1. A pre-formed resonator bulb can function in a stand-alone application. Bulbs embodied according to the invention are instead used as hollow interior forms which will withstand pressures exerted by concrete in the panel molding process.
Referring to FIG. 2, after having pre-formed resonator bulb 10, the invention process advances to a second stage of molding, preferably using jig form 12. A resonator panel is molded using pre-formed resonator bulbs 10 and concrete together in panel molding region 14. Wood, metal, plastic or other suitable material embodies jig form 12. Base 16 has a horizontal upper surface floor 18 for forming a sound-receiving front face surface on concrete once poured in molding region 14. Frame 20 has a vertical inside surface border 22 around the periphery for forming an edge surface on the concrete. Frame 20 is a preferably rectangular with inside surface 22, outside surface 24 and top surface 26 of which the elevation determines the thickness of panels molded in jig form 12.
Referring to FIG. 3, the surface of floor 18 is generally flat except in resonator location areas which accommodate pre-formed resonator bulbs 10 as shown for example at axis T3 in a cross-section along vertical plane 3--3 taken from FIG. 2. Floor 18 at each resonator location has an anchor hole 28 surrounded by sidewall 30 descending to bottom 32.
Cylindrical pin 34 is made of a material as mentioned above. Lower end 36 is scaled for a friction fit into anchor hole 28. Pin 34 projects perpendicularly from surface 18 to an upper end 38 and is scaled to fit through the area A of the opening of port P of pre-formed resonator bulb 10. Pin 34 when fitted into port P aligns bulb 10 at a resonator location, possibly in a pattern as shown by FIG. 2. Pins 34 brace respective bulbs 10 against impact shock followed by turbulence of concrete being poured into molding region 14.
Concrete (not shown) filling jig form 12, afterwards while it sets, compresses bulbs 10. Tension increases in each bulb 10 causing minimal volume changes of its cavity C until the bulb wall tension counter-balances the weight of concrete. The equilibrium cavity volume is finalized when the concrete settling around the molding surface M outside bulb 10 is done.
Referring to FIG. 4, when the poured concrete dries, jig form 12 is removed, which leaves resonator panel embodiment 40 at the end of the second stage. The portion of concrete 42 which was molded horizontally on the floor 18 of jig form 12 now becomes the panel's vertically standing sound receiving front face surface 43 bounded by edges E around port areas A of openings of ports to bulbs 10 in an array corresponding to the resonator locations shown in FIG. 2. The edge surfaces 44h along the height and 44w along the width in the thickness dimension correspond to vertical inside surface border 22 of frame 20.
FIG. 5 shows an example bulb 10 in a cross-section along plane 5--5 inside panel 40 taken from FIG. 4 as seen along arrow 45. Bulb 10 has outer side molding surface M bounded by an edge E which circumscribes a port are A. Since hollow bulbs instead of conventional rigid solid interior forms were used, there are no solid form obstructions needing to be cleared from the resonator panel embodiment 40. After stiffening, concrete 42 reaches a final amount of compression of the resonator bulbs 10 which remain permanently inside panel 40. The surrounding concrete reinforces each bulb 10 against incidental shocks to resonator panel 40. The panel has the advantage of reducing the amount of concrete needed, as well as the weight of, the panel.
Notwithstanding that the invention has been disclosed in terms of its preferred embodiment, persons skilled in the art will appreciate that the embodiment could be modified. For example, the first stage can have resonator bulbs pre-formed by other than blow molding techniques. The second stage can have a jig form embodied by an assembly of more numerous subcomponents, or alternatively in a single piece monolithically molded with an integral base and pins. A further alternative embodiment can omit pins from the jig form for holding pre-formed resonator bulbs having outside surfaces dimensioned to fit into anchor holes. To insure against pre-formed resonator bulbs floating in liquid concrete, the anchor means can be supplemented. The preferred concrete medium can be replaced by a substitute medium. Certain selected media could pre-form bulbs in the first stage and then also be filled in between the bulbs in the second stage. This could merge the interface boundaries between them and even mold a monolithic panel.
Accordingly, the invention, to the extent of any such variations, is intended to be covered in interpreting the scope of the following claims. | Acoustic resonator means are embodied through successive stages of molding. A first stage pre-forms resonator enclosures without solid forms inside. After resonator enclosures have been pre-formed they advance to a second stage. A jig form molds pre-formed resonator bulbs and concrete together in a panel molding region to form a resonator panel. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part of U.S. patent application Ser. No. 10/607,237, entitled “APPARATUS AND METHOD FOR MONITORING OF AN AUTOMATIC DEICING CONTROLLER”, filed Jun. 26, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to deicing equipment, and, more particularly, to automatic controls for deicing equipment used to melt and remove snow and ice from pavement, roofs, gutters, downspouts and the like.
[0004] 2. Description of the Related Art
[0005] Electric and hydronic heaters are commonly used to melt ice and snow. Applications include pavement and similar structures, but also include roofs, downspouts and gutters. Pavement applications include sidewalks, driveways, stairs, drive through window areas, building portals, loading docks, bridge decks, parking garages and off ramps, etc.
[0006] Typically, automatic controls are utilized to sense ambient temperature and moisture to control ice removal heating equipment. Heater elements may include hydronic tubing installed under or proximate to areas in which the removal of ice or snow is desirable. Hydronic systems include an interface with a heating system that provides energy for the removal of ice and snow. Electrical heating cables may also be employed that consist of stranded copper wires separated by a semi-conductor polymer enclosed in one or more layers of organic insulating material, this type of electrical cable is often referred to as self-limiting or self-regulating heating cable. Additionally, an insulated resistant wire may be used, which maintains a relatively constant resistance as it dissipates heat. The insulation may consist of magnesium oxide or various polymeric materials.
[0007] The status of, and functioning of, the automatic control can be determined by way of a visual indicator on the control or an electrical interface to which an electrical device can be connected to analyze the functioning of the control. The visual indicator thereon may indicate the sensed temperature, the presence of electrical power and whether moisture is detected. Additionally, the automatic control can be checked if the temperature and moisture are controlled to a point of causing the controller to energize the heating system to thereby verify operation of the control system.
[0008] The power density used for the melting of snow on pavement varies between 30 and 60 Watts/ft 2 , with 45-50 Watts/ft 2 being typical. In comparison, the heaters used to melt snow and ice on a precipitation sensor has typically been at least 380 Watts/ft 2 . This power density is more than eight times greater than that of the pavement heaters which are typically controlled by the controller. The higher power density has been utilized by controllers to determine the amount of frozen precipitation so that the time in which the precipitation stopped can be determined and to burn through any accumulated snow on the sensor. This prior art approach results in a guess as to when the precipitation on the pavement will be dissipated. It is a guess because the precipitation on the sensor is typically dissipated before the moisture on the pavement is melted. To compensate for the unknown the heater is held on for a predetermined time to ensure the melting of the ground precipitation. The typical heater hold-on time is usually 2½ to 10 hours.
[0009] What is needed in the art is an automatic heater controller that tracks the melting of the precipitation on the pavement or walkway by way of a remotely mounted sensor.
SUMMARY OF THE INVENTION
[0010] The present invention provides a monitoring method and apparatus having a sensor that tracks the melting of the precipitation on the heated pavement.
[0011] The invention comprises common in one form thereof, a snow melting system including a controller, a first heater supplying heat under the control of the controller, the first heater supplying heat at a power density, a moisture detection apparatus located apart from the first heater, the moisture detection apparatus communicatively coupled to the controller and a second heater located proximate to the moisture detection apparatus, the controller directing power to the second heater at an other power density, the other power density substantially the same as the power density.
[0012] An advantage of the present invention is that a shorter hold-on time for the heater in the pavement can be utilized.
[0013] Another advantage is that the controller accurately determine's the completion of the moisture dissipation on a pavement by melting the frozen precipitation on the sensor at the same rate as that utilized in the heating element associated with the pavement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
[0015] [0015]FIG. 1 is combination perspective view of an embodiment of a heater control of the present invention and a schematical form of typical external circuitry attached thereto;
[0016] [0016]FIG. 2 is a schematic diagram of a heater control of FIG. 1;
[0017] [0017]FIG. 3 is a block diagram of a method used by the heater controller of FIGS. 1 and 2; and
[0018] [0018]FIG. 4 is a block diagram of another method used by the heater controller of FIGS. 1 and 2.
[0019] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring now to the drawings, and more particularly to FIG. 1, there is shown one embodiment of a deicing control system 10 of the present invention. System 10 includes power system 12 and control system 14 .
[0021] Power system 12 includes power conductors 16 and 18 , control conductor 20 , relay coil 22 , relay contact 24 and heater system 26 . Power conductors 16 and 18 are connected to electrical power such as a 120 volt circuit. Power conductors 16 and 18 also provide power to control system 14 . Control conductor 20 receives a signal from control system 14 that drives relay coil 22 causing a controllable connection of relay contact 24 thereby allowing power to flow from power conductor 16 through heater system 26 to power conductor 18 . Heater system 26 can be the controlling pump of a hydronic heating system 26 or an electrical heating element 26 .
[0022] Now, additionally referring to FIG. 2, there is shown a control circuit 30 , which is part of control system 14 . Control system 14 also includes moisture detector 32 and temperature detector 34 . Moisture detector 32 includes a moisture grid that is a spaced apart interdigitated set of conductors exposed on the top of control system 14 . Moisture, in the form of water, ice, snow and/or sleet on the surface of moisture detector 32 is detected by a current flow between fingers of the interdigitated conductors.
[0023] Prior moisture detectors measured the conductivity between the interdigitated conductors using an uninterrupted supply of a DC voltage. This causes electrochemical problems including polarization and copper electroplating that reduces the life expectancy and reliability of the sensor. Polarization occurs when DC current flows through the grid when wet. The water from melted snow and ice becomes an electrolyte due to atmospheric contamination and the ions therefrom are positioned, due to the constant electro-potential on the interdigitated fingers. However, the circuit and method employed by the present invention reduces this problem to a negligible proportion by employing an active sensing technique that reduces the current through the moisture detection grid by more than an order of magnitude. Further, the circuit detects moisture on the sensing grid in the form of ice, in any form, without the need for heating the sensor to turn the ice into water. An advantage of this approach is that heat is not dissipated in the moisture sensor at a higher rate than that utilized in the pavement, or other application areas, where the heating element is distributing the heat. The advantage of this is that the moisture on the moisture detector will dissipate at the same rate as the moisture on the ground or other area under the control of control system 14 . The selection of the power density that is applied to the moisture sensor to melt the snow and ice on the conductive grid is such that it operates to allow the snow and ice to be removed at approximately the same rate as that on the ground. This advantageously permits a shorter hold-on time of the heating system thereby saving energy. The hold-on time, of approximately one hour, ensures complete melting of the moisture and the evaporation of any standing melt water.
[0024] Now, additionally referring to FIG. 4, there is illustrate a method 200 that is utilized to determine when moisture detector 32 is energized and when heater elements 26 located in pavement or walkway 27 are energized. Method 200 starts at step 202 and continues to step 204 , where the temperature of the air is determined to be above or below a predetermined value such as 38° F. If temperature sensor 34 detects a temperature equal to or above the predetermined value then method 200 returns to step 204 .
[0025] If temperature sensor 34 detects an air temperature below the predetermined value, then method 200 proceeds to step 206 . At step 206 , moisture sensor 32 is turned on by controller 36 .
[0026] At step 208 , if moisture is detected by moisture sensor 32 , method 200 proceeds to step 212 . If moisture sensor 32 does not detect moisture then method 200 proceeds to step 210 .
[0027] At step 212 , heating element 26 is turned on, thereby providing heat to pavement 27 . When the heat is turned on at step 212 , controller 36 additionally activates heaters 42 . Heaters 42 are sized to provide the same or substantially the same power density as that being applied to heater element 26 is pavement 27 .
[0028] At step 214 , method 200 de-energizes moister sensor 32 for a predetermined time, such as ten minutes. After the completion of the predetermined time period, moisture sensor 32 is reenergized and method 200 proceeds to step 208 .
[0029] If no moisture is then detected at step 208 , method 200 proceeds to step 210 . At step 210 , power to heaters 42 is removed and heat to heating element 26 is held on for a predetermined time, such as one hour, and then automatically heating element 26 is de-energized. Method 200 then proceeds back to step 204 . Advantageously, since the melting of precipitation on moisture detector 32 approximates the rate of the melting of precipitation on pavement 27 , a relatively short hold-on time can be used, thereby reducing energy costs.
[0030] Power to the moisture sensor is turned off at temperatures above 38° F. At lower temperatures excitation of moisture detector 32 is continuous until precipitation is detected. Thereafter, moisture detector 32 is electrically activated at predetermined intervals, such as every six minutes, for a few seconds to check for the presence of moisture. If moisture had been previously detected, then the detection of a lack of moisture marks the beginning of the heater hold-on time interval. This modulating of the DC voltage on moisture detector 32 advantageously reduces the average current flowing through moisture detector 32 thereby prolonging its life.
[0031] Alternatively, at step 212 , when energy is applied to heating element 26 , the energy supplied to resistors 42 may be modulated by controller 36 to thereby provide a power density to moisture detector 42 that matches the power density of heating element 26 in pavement 27 . This advantageously allows a standard heating element 42 to be utilized with the power density being under the control of controller 36 . The selection of the power density to be applied to moisture detector 32 by way of heating elements 42 can be predetermined or selected at the time of installation.
[0032] Additionally, another technique in detecting moisture involves the measurement of AC conductivity of the moisture-sensing grid of moisture detector 32 . Low frequency AC excitation reduces the electrochemical deterioration of the surface of the moisture sensing grid when it is exposed to precipitation in any form, since the average current is zero. Further, the measurement of the AC capacitance of the moisture-sensing grid of moisture detector 32 may be used to detect moisture.
[0033] Control circuit 30 incorporates a negative temperature coefficient precision thermistor 34 to convert the ambient temperature into a voltage value using half of a DC excited Wheatstone bridge. The other half of the bridge is supplied by a successive approximation routine that utilizes an analog-to-digital converter in microcontroller 36 . Since both halves of the Wheatstone bridge are excited by supply voltage V + , the encoded temperature value is essentially independent of variations in V + .
[0034] Control circuit 30 includes microcontroller 36 , relay 38 , field effect transistor (FET) 40 , heater elements 42 , FET 44 , FET 46 ; capacitor 48 and resistor 50 . Controller 36 is interconnected with temperature detector 34 , FETs 40 , 44 and 46 . FET 40 controls the driving power to relay 38 , thereby providing an electrical connection between power line 16 and control line 20 . This places microcontroller 36 in control of the power supplied to heating element 26 . FET 44 is connected to resistive elements 42 that are proximate to and/or integrated with moisture detector 32 . Resistors 42 provide heat to moisture detector 32 when energized by FET 44 . FET 46 functions as an operational amplifier having a feedback capacitor 48 and a feedback resistor 50 . Feedback capacitor 48 serves to integrate current conducted from moisture detector 32 . Feedback resistor 50 provides a leak off of the integrated value otherwise integrated by FET 46 , capacitor 48 and current from moisture detective 32 .
[0035] Conductors 52 , 54 , 56 , 58 and 60 electrically interconnect microcontroller 36 with elements of control circuit 30 . Conductor 52 connects controller 36 with FET 40 thereby allowing controller 36 to turn power on to heater element 26 in a controllable manner. Conductor 54 is interconnected with controller 36 and FET 44 thereby controlling power to heating elements 42 that heat moisture detector 32 . The control of heat to moisture detector 32 is selected such that the power density applied thereto matches the power density in the deicing area. Microcontroller 36 advantageously controls the power supplied to heater elements 42 , in a programmed manner, to substantially match the heat density applied to moisture detector 32 to that supplied to the deicing area by way of heating element 26 . Conductor 56 provides a voltage level from thermistor 34 that corresponds with the external temperature. The voltage level is utilized by controller 36 to determine the ambient temperature and decide when to activate FETs 40 , 44 and 46 . For example, if the temperature detected from thermistor 34 is above 38°, FETs 40 , 44 and 46 will not be activated. When the temperature detected is below 38° F. moisture detector 32 , by way of conductors 58 and 60 , is activated to determine if any moisture is present on moisture detector 32 . If moisture is detected on moisture detector 32 , then conductor 52 is energized thereby causing FET 40 to be conductive causing the contact in relay 38 to close, thereby providing power to relay coil 20 , causing relay contact 24 to close, thereby directing electrical power to heating element 26 . FET 44 is modulated according to a prescribed power density to approximate the power density of heater element 26 . Once moisture is detected from moisture detector 32 , conductor 60 is de-energized for a predetermined amount of time. After the predetermined amount of time conductor 60 is re-energized to again detect the presence or absence of moisture on moisture detector 32 . Conductor line 58 serves as a sensor input to microcontroller 36 and conductor 60 supplies power to moisture detector 32 . Microcontroller 36 is a microprocessor driven controller and in the preferred embodiment a microchip 12C672 8-bit Harvard Architecture device is utilized. Microcontroller 36 advantageously has analog input and digital input/output ports, which are correspondingly interconnected to conductors 52 , 54 , 56 , 58 and 60 .
[0036] Now, additionally referring to FIG. 3, there is shown a method 100 that is executed by microcontroller 36 . Method 100 is initiated at step 102 , upon power on of control system 14 or upon a manual initiation, for example, by the pressing of a button not shown. Upon initiation, method 100 proceeds to step 104 in which controller 36 obtains the operational status of control system 14 . Operational status includes a test of moisture detector 32 , a reading of temperature reported by detector 34 and the status of power applied to FETS 40 , 44 and 46 . Status information thus obtained at step 104 is then available for transmittal at step 106 .
[0037] At step 106 , status information about control system 14 is directed to heater element 26 by way of relay 38 and relay elements 22 and 24 . The information is conveyed by a predetermined pulsing of relay 38 causing the current flowing through heating element 26 to be turned on and off in a predetermined pattern. The pulsing of the current through the heater element 26 can be detected by an operator having placed a clamp-on amp meter around conductor 28 to thereby detect the pattern being pulsed from control system 14 . The information passed to heater element 26 includes the current temperature detected by temperature detector 34 and whether or not moisture detector 32 is detecting any moisture. Additionally, status regarding microcontroller 36 and the status of relay 38 upon turn on may be directed to heater element 26 .
[0038] Method 100 proceeds to step 108 wherein controller 36 reads a memory contained within microcontroller 36 that contains historical operating information. The historical operating information may include performance in a previous time period such as the last time controller 36 energized heater element 26 and the duration thereof.
[0039] At step 110 , microcontroller 36 sends the historical data to heater element 26 again by a predetermined pulsing pattern of power under the control of FET 40 , relay 38 and relay elements 22 and 24 . The information sent to heater element 26 is thereby interpreted by an operator observing a voltmeter detecting the application of voltage to heater element 26 or by way of an amp meter detecting the current through conductor 28 . Alternatively, if relay elements 22 and 24 include a light circuit, the operator can detect the pulse pattern by observing the light on the relay or listen to the relay closures. Advantageously, the present invention conveys information regarding control system 14 to a user by way of a pulse pattern to the heating element, thereby allowing control system 14 to provide operating information without the need of applying a controlled temperature and moisture environment to temperature detector 34 and moisture detector 32 to thereby test the operation of control system 14 .
[0040] The information provided from control system 14 to heater element 26 and conductor 28 may be in the form of pulsing steps, which include varying the time duration of pulses or the frequency of pulses in the pattern. The pattern of pulses is completed in a relatively short period of time upon turn power-up of control system 14 . The relatively short period of time may be less than one minute in duration and more specifically less than 30 seconds. Additionally, the pulse pattern may be delayed for a short period of time allowing an operator to move from a power on switch to the amp meter to thereby detect the information. The delay in operation may be a predetermined time such as 2 minutes.
[0041] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. | A snow melting system including a controller, a first heater supplying heat under the control of the controller, the first heater supplying heat at a power density, a moisture detection apparatus located apart from the first heater, the moisture detection apparatus communicatively coupled to the controller and a second heater located proximate to the moisture detection apparatus, the controller directing power to the second heater at an other power density, the other power density substantially the same as the power density. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates generally to a method for transferring data, and more particularly to a method for transferring data from a host computer to a storage media using selectable caching strategies.
Write-back caching is an exemplary environment for transferring data from an initiator device to a target device. Write-back caching refers to a method of executing write requests where an initiator device such as a host computer transfers write request data to a target device such as a caching disk array controller which then transfers the write request data to storage media. Depending upon the particular write-back caching strategy being implemented by the controller, the write request data can either be written immediately to the storage media, or the write request data can be temporarily stored in a cache memory as unwritten or “dirty data” and then “flushed” or written to the storage media at some later point in time. In both cases, the controller sends back status information to the host computer indicating that the write request is complete so that the host computer can continue executing a software application. What is meant herein by the use of the term “dirty data” is data that is located in cache memory which is not yet been written to storage media. To provide meaning to the following terms “flush”, “flushed” or “flushing” which are used herein, it should be appreciated that the act of “flushing” data means writing dirty data to storage media.
The performance of a host computer when executing a certain software application is dependent, at least in part, upon the particular caching strategies that are implemented by the caching disk array controller. More specifically, the performance of the host computer can be optimized by implementing the most appropriate caching strategies for the particular software application being executed.
With regard to write-back caching, the host computer may experience optimal performance when executing a first software application with write request data written immediately to storage media, while the host computer may experience optimal performance when executing a second software application with write request data stored in cache memory for as long as possible before it is written to storage media. Further, the host computer may experience optimal performance when executing a third software application with write request data stored in cache memory for a particular time interval, or until a particular amount of write request data has been stored in the cache, before it is written to storage media.
Heretofore, a host computer was unable to adjust or tune the caching strategy used for writing its write request data to storage media during execution of various software applications. It would therefore be desirable to provide a method in which the host computer would adjust the caching strategy used for writing its write request data to storage media during execution of various software applications so that the host computer could optimize its performance during execution of the various software applications.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention, there is provided a method for transferring data to a storage medium. The method includes the steps of (1) providing a controller having a cache memory, (2) generating a cache-flushing parameter in the host computer, (3) transferring the cache-flushing parameter from the host computer to the controller, and (4) writing a quantity of write request data from the cache memory of the controller to the storage medium in accordance with the cache-flushing parameter.
Pursuant to another embodiment of the present invention, there is provided a method of transferring data from a host computer to a storage media. The method includes the steps of (1) sending a first caching parameter which defines a first caching strategy to a controller, (2) transferring a first quantity of data from the host computer to the storage media based on the first caching parameter, (3) sending a second caching parameter which defines a second caching strategy to the controller, and (4) transferring a second quantity of data from the host computer to the storage media based on the second caching parameter.
Pursuant to yet another embodiment of the present invention, there is provided a method for transferring data to a storage device. The method includes the steps of (1) updating a cache-flushing parameter associated with a cache memory, and (2) flushing the cache memory to the storage device in accordance with the cache flushing parameter after the updating step.
Pursuant to still yet another embodiment of the present invention, there is provided a method for controlling cache flushing characteristics of a storage device, with the storage device having a controller which includes a cache memory. The method includes the steps of (1) sending a cache-flushing parameter to the controller, and (2) flushing the cache memory of the controller in accordance with the cache-flushing parameter.
It is therefore an object of the present invention to provide a new and useful method for dynamically changing a cache flushing algorithm.
It is another object of the present invention to provide a new and useful method of changing cache flushing characteristics through host selectable parameters.
It is a further object of the present invention to provide a new and useful method for varying how much of a cache memory will be flushed at one time using a host selectable parameter.
It is yet another object of this invention to provide a new and useful method for varying a time interval for writing unwritten write request data to a storage media.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a host computer and a multi-controller disk array apparatus which is responsive to host-selectable parameters for changing cache flushing strategies in accordance with the method of the present invention;
FIG. 2 illustrates a memory buffer format with fields containing host-selectable parameters;
FIGS. 3A and 3B are graphs illustrating exemplary relationships between a range of host-selectable cache flush modifiers and corresponding time intervals for flushing a cache memory; and
FIG. 4 is a graph illustrating a begin on-demand flush threshold, end on-demand flush threshold and a dirty maximum threshold which define the operating parameters for an exemplary on-demand cache flushing operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Referring now to FIG. 1, there is shown a computer system 2 comprising a host computer 10 , a peripheral disk drive apparatus 12 connected to the host computer 10 , and a sub-system uninterruptable power supply (UPS) 13 associated with the disk drive apparatus 12 . The host computer 10 includes a first host adapter 14 and a second host adapter 16 both of which function to interface the host computer 10 to various peripheral devices such as the disk drive apparatus 12 . The sub-system UPS 13 only provides power to the disk drive apparatus 12 .
The disk drive apparatus 12 includes a first caching disk array controller 18 , a second caching disk array controller 20 , a plurality of back-end buses or channels 22 A- 22 E, and at least one storage medium 24 associated with each channel 22 A- 22 E. In the described embodiment, the channels 22 A- 22 E are SCSI channels which connect the first controller 18 to the second controller 20 . SCSI is an acronym for a Small Computer System Interface which defines a communications protocol standard for input/output devices. The first version of the standard, SCSI-1, is described in ANSI X3.131-1986 and is incorporated herein by reference. The SCSI-1 specification has been upgraded with an expanded interface referred to as SCSI-2. The SCSI-2 specification is described in ANSI Document No. X3.131-1994 which is also incorporated herein by reference.
In the described embodiment, there are five disks 24 A- 24 E which cooperate to form a one-column disk array 26 , and which are individually connected to the controllers 18 , 20 via the buses 22 A- 22 E, respectively. The disk array 26 incorporates a design termed “Redundant Array of Inexpensive Disks” (RAID). Five levels of RAID design, termed RAID-1 through RAID-5, are known in the art and are described in the publication titled “A Case for Redundant Arrays of Inexpensive Disks (RAID)” by David A. Patterson, Garth Gibson and Randy H. Katz; University of California Report No. UCB/CSD 87/391, December 1987, which is incorporated herein by reference. It should be appreciated that the disk array 26 can include additional columns of disks connected to the respective buses 22 . For example, a 5 by 6 disk array comprising thirty (30) disk drives can be formed by connecting 5 additional disks to each bus 22 A- 22 E, respectively.
The host computer 10 , and more particularly, the host adapters 14 , 16 are connected to the respective disk array controllers 18 , 20 via separate buses or channels such as host SCSI buses 28 and 30 . The first controller 18 includes a data processor such as a conventional microprocessor 31 , an input/output processor or secondary processor 32 , a cache memory 33 , and a cache battery 35 . The cache memory 33 can be partitioned into at least two separate areas, a primary cache memory area 34 . and an alternate cache memory area 36 . Likewise, the second controller 20 includes a data processor such as a conventional microprocessor 37 , an input/output processor or secondary processor 38 , a cache memory 39 and a cache battery 41 . The cache memory 39 is partitioned into at least two separate areas, a primary cache memory area 40 and an alternate cache memory area 42 . The cache batteries 35 , 41 exclusively power the cache memories 33 , 39 , respectively, in the event of a power failure or interruption to prevent the loss of data stored in the cache memories 33 , 39 .
The input/output processors 32 , 38 execute ASIC-specific (Application Specific Integrated Circuit) instructions independent from controller firmware which is executed by the respective microprocessors 31 , 27 . One example of a suitable input/output processor is the SCSI Input/Output Processor (SIOP) 53C825 chip manufactured by Symbios Logic Inc. of Fort Collins, Colo. The 53C825 input/output processor executes SCRIPTS instructions which are an ASIC-specific instruction set specifically designed for controlling the 53C8XX family of Symbios Logic Inc. products.
The controllers 18 , 20 can operate one of two modes, passive-active or dual-active. In the dual-active mode of operation, both controllers 18 , 20 have portions of their respective cache memories 33 , 39 allocated for exclusive use by the other controller. Thus, in the dual-active mode, both controllers 18 , 20 function as a primary controller and an alternate controller. More specifically, the primary cache memory area 34 is assigned to controller 18 for use during cache read/write requests from the host computer 10 , and the alternate cache memory area 36 is assigned to controller 20 for use in mirroring write request data which is stored in the primary cache memory area 40 of controller 20 . Controller 20 is responsible for managing the write request data that it mirrors or stores in the alternate cache memory area 36 .
Likewise, the primary cache memory area 40 is assigned to controller 20 for use during cache read/write requests from the host computer 10 , and the alternate cache memory area 42 is assigned to controller 18 for use in mirroring write request data which is stored in the primary cache memory area 34 of controller 18 . Controller 18 is responsible for managing the write request data that it mirrors into the alternate cache memory area 42 .
The alternate cache memory areas 42 , 36 are allocated to the respective controllers 18 , 20 during the system configuration phase of start-up operations for the computer system 2 . It should be appreciated that the alternate cache memory area 42 is assigned the same corresponding memory addresses as assigned to the primary cache memory area 34 , and that the alternate cache memory area 36 is assigned the same corresponding memory addresses as assigned to the primary cache memory area 40 thus simplifying mirroring operations by avoiding the need for virtual memory mapping operations.
In the passive-active mode of operation, one of the controllers, such as controller 18 , functions as a primary controller which receives read/write requests from the host computer 10 while the other controller, controller 20 , functions as an alternate controller which provides cache memory for mirroring the write request data under the direction of the primary controller 18 as described above with regard to the dual-active mode of operation.
It should be appreciated that the primary cache memory area 34 does not have to be the same size as the alternate cache memory area 42 , and that the primary cache memory area 40 does not have to be the same size as the alternate cache memory area 36 . By way of example, the alternate cache memory area 36 has to only be large enough to handle all of the mirrored write request data that controller 20 wants to store. At any given time, the primary cache memory area 40 , and similarly, the primary cache memory area 34 , has X % of read cache, Y % of write cache and Z % of unused memory allocated thereto, where X+Y+Z=100% of the primary cache memory area 40 . If the maximum amount of write request data (Y % of write cache) that can be stored in the primary cache memory area 40 is less than 100% of the primary cache memory area 40 , then the alternate cache memory area 36 can be smaller than the primary cache memory area 40 . That is, the alternate cache memory area 36 need only be as large as the amount of the primary cache memory area 40 allocated for write caching.
The present invention provides for adjustment of the caching strategies implemented by the controllers 18 , 20 . For ease of description, further reference will be limited to adjustment of the caching strategies implemented by controller 18 only. However, it is to be understood that adjustment of the caching strategies implemented by controller 20 occur in an analogous manner.
Referring now to FIG. 2 there is shown an exemplary memory buffer 44 with a plurality of fields containing host-selectable caching parameters that control the operation of the controller 18 in accordance with the method of the present invention. The memory buffer 44 is maintained in the controller 18 for receiving data and instructions from the host computer 10 the form of a vendor-unique caching page. When the host computer desires to change the way that caching operations are being implement by the controller 18 , the host computer 10 updates the memory buffer 44 via a mode select page command followed by the vendor-unique caching page directed to the memory buffer 44 . In the embodiment being described, the host computer 10 transfers the 63-byte vendor-unique caching page in the form of a data stream that contains the host-selectable parameters to the memory buffer 44 . The parameters are then used by the controller 18 to vary or modify the caching strategy or strategies implemented in the controller 18 . Note that a portion of the 63-byte vendor-unique caching page that is transferred by the host computer 10 may be reserved for other purposes.
The controller 18 executes the mode select page command sent from the host computer 10 on an advisory basis. That is, the controller 18 takes into consideration not only the mode select page command from the host computer 10 , but also other events that are occurring within the computer system 2 that may require the controller 18 to perform a task differently from that requested by the host computer 10 . For instance, the controller 18 may have to flush the primary cache memory area 34 at an interval different from that specified by the host computer 10 in the memory buffer 44 . The memory buffer 44 can also be used by the host computer 10 to retrieve configuration information from the controller 18 by issuing a mode sense page command which causes the contents of the memory buffer 44 to be read into the host computer 10 .
The fields within the memory buffer 44 are divided into three groups, namely, a cache control flag group, a cache operating state flag group, and a cache control field group. The cache control flag group contains the following one-bit cache control flags: allow write caching without batteries (CWOB) flag 46 , force write-through on two-minute warning (FWT) flag 48 , and cache mirror enable (CME) flag 50 .
If the CWOB flag 46 (allow write caching without batteries flag) is set to one (1), the controller 18 will permit write caching operations without the presence of the cache batteries 35 , 41 . The CWOB flag allows the use of write caching with a volatile cache memory such as the cache memory 33 and the uninterruptable power supply (UPS) 13 . The UPS 13 provides battery back-up to the disk drive apparatus 12 including the cache memories 33 , 39 in the event of a power failure to the controller 18 . The value specified by the CWOB flag 46 is maintained on a logical unit basis. The term “logical unit” is used herein to mean a group of one or more disks 24 that the host computer 10 sees as a single unit. Each logical unit comprises a plurality of 512 byte sectors or blocks. A RAID controller, such as controller 18 , can define multiple logical units, wherein each logical unit can be configured to implement a different RAID level.
The FVVT flag 48 (force write-through on two-minute warning flag) provides control over the actions taken by the controller 18 if a UPS two-minute warning is received while write-back caching is enabled on a logical unit. That is, if battery power in a system-wide UPS (not shown) is about to be depleted, then a UPS two-minute warning will be issued. If a logical unit has write-back caching disabled, the FWT flag 48 has no effect on the logical unit.
The default for the FWT flag 48 is off, i.e. set to zero (0), indicating that the controller 18 will not force write-back caching to a disabled state on the logical unit when a UPS two-minute warning is received. Thus, write-back caching operations will continue on the logical unit as long as write request commands are received from the host computer 10 . The controller 18 provides the highest possible write throughput from the host computer 10 with the FWT flag 48 is set to zero (0). This action is desirable for a host computer that does not have battery back-up for its internal memory and needs to flush its memory as quick as possible before the system-wide UPS is depleted. Thus, by continuing to use write-back caching after a UPS two-minute warning is received, there is a better chance of flushing the host computer's memory before battery power in the system-wide UPS is depleted.
If the FWT flag 48 is turned on, i.e. set to one (1), the controller 18 will disable write-back caching and flush any dirty data in the cache memory 33 to the storage media. This action is desirable for a host computer that does have its own UPS (not shown) or battery-backed memory (not shown), and thus does not have an urgent need to ensure that all data in its memory has been written before the system-wide UPS battery is depleted. The controller 18 flushes the dirty data to storage media so that the sub-system UPS 13 will not have to be expended to store any dirty data when the system-wide UPS battery is depleted.
The FWr flag 48 only controls enabling or disabling the cache memory 33 and will not affect read caching operations. Cache flushing operations can also be controlled by using a TMW Flush Modifier field 78 discussed further below.
The CME flag 50 (cache mirror enable flag) is used to control the use of the cache mirroring capabilities in redundant controller configurations. If the CME flag 50 is set to one (1), cache mirroring is enabled and a copy of the write request data is placed in the alternate cache memory area 42 of the alternate controller 20 as previously described. If the CME flag 50 is turned off, the controller 18 will maintain a copy of the write request data from the host computer 10 in its own cache memory 33 , but not copy the data to the alternate controller 20 .
The CME flag 50 is maintained for each logical unit and thus the cache mirroring feature can be enabled or disabled for each individual logical unit. If write-back caching is disabled in a standard SCSI caching mode page, then the CME flag 50 and the other write-back caching parameters in the vendor-unique caching page are ignored. The standard SCSI caching mode page provides a single bit for enabling and disabling write-back caching in addition to limited algorithm control. However, the standard SCSI caching mode page does not provide for the same level of adjustment or tuneablity as provided for in the vendor-unique caching page of the present invention.
The cache operating state flag group contains the following one-bit cache operating state flags: write cache active (WCA) flag 52 , read cache active (RCA) flag 54 , batteries OK (BOK) flag 56 , alternate controller batteries OK (ABOK) flag 58 , cache mirroring active (CMA) flag 60 , alternate controller cache mirroring active (ACMA) flag 62 , batteries present (BPR) flag 64 and alternate controller batteries present (ABPR) flag 66 . The cache operating state flags are returned by the controller 18 on a mode sense command. The mode sense command permits the host computer 10 to determine the current configuration of a SCSI target device, such as controller 18 . The cache operating state flags are ignored if set on a mode select command. The mode select command permits the host computer 10 to configure a SCSI target device, such as the controller 18 .
When the WCA flag 52 (write cache active flag) is set to one (1), the controller 18 uses write-back caching to service write requests from the host computer 10 . When the WCA flag 52 is set to zero (0), write-back caching has either been disabled by the host computer 10 or the controller 18 has temporarily de-activated the feature. The WCA flag 52 does not indicate if write back data is present in the cache memory 33 .
When the RCA flag 54 (read cache active flag) is set to one (1), the controller 18 uses read caching. When the RCA flag 54 is set to zero (0), read caching has either been disabled by the host computer 10 , or the controller 18 has temporarily de-activated the RCA feature. The RCA flag 54 does not indicate if cached data or parity is present in the cache 33 .
When the BOK flag 56 (batteries OK flag) is set to one (1), the cache battery 35 in controller 18 is operational. If the BOK flag 56 is set to zero (0), the battery power to the cache memory 33 has failed or there is no battery 35 present. If the battery 35 is not present, the batteries present flag 64 will be off, i.e. set to zero (0).
When the ABOK flag 58 (alternate controller batteries OK flag) is set to one (1), the cache battery 41 on the alternate controller 20 is operational. If the ABOK flag 58 is set to zero (0), the battery power to the cache memory 39 has failed or there is no battery 41 present. If the battery 41 is not present, the alternate controller batteries present flag 66 will be off, i.e. set to zero (0).
When the CMA flag 60 (cache mirroring active flag) is set to one (1), the controller 18 mirrors write request data stored in the primary cache memory area 34 to the alternate cache memory area 42 of controller 20 . When the ACMA flag 62 (alternate controller cache mirroring active flag) is set to a one (1), the alternate controller 20 mirrors write request data stored in the primary cache memory area 40 to the alternate cache memory area 36 of primary controller 18 .
If the BPR flag 64 (batteries present flag) is set to one (1), then controller 18 has detected that cache battery 35 is available to power the cache memory 33 in the event of a power interruption. If the ABPR flag 66 (alternate controller batteries present flag) is set to one (1), the alternate controller 20 has detected that the battery 41 is available to power the cache memory 39 in the event of a power interruption.
The cache control field group contains the following cache control fields: read caching algorithm field 68 , write caching algorithm field 70 , cache flush algorithm field 72 , cache flush modifier field 74 , two-minute warning flush algorithm field 76 , two-minute warning flush modifier field 78 , demand flush threshold field 80 , and the demand flush account field 82 .
The parameter specified in the read caching algorithm field 68 is used to select a particular read caching algorithm. Likewise, the parameter specified in the write caching algorithm field 70 is used to select a particular write caching algorithm. Further, the parameter specified in the cache flush algorithm field 72 is used to select a particular cache flushing algorithm.
The parameter specified in the cache flush modifier field 74 is used to vary cache flushing characteristics such as a flushing schedule for a cache flushing algorithm implemented by the controller 18 . More specifically, the value specified in the cache flush modifier field 74 indicates to the controller 18 , the time interval to use for cache flushing if the “begin demand flush” threshold (discussed further below) is not reached. The parameter specified in the cache flush modifier field 74 is selected by the host computer 10 to optimize the performance of the host computer 10 when executing a particular software application. The host-selectable cache flush modifier parameter indirectly specifies the amount of time that unwritten write request data is to remain in the cache memory 33 . The parameter ranges from zero (0) to fifteen (15), where zero (0) means that the unwritten write request data is to be written as soon as possible, and fifteen (15) means that the unwritten write request data can remain in the cache memory 33 at least until another host write request demands the use of cache memory 33 .
If the cache flush modifier parameter is set to zero (0), then immediate cache flushing is indicated. Thus, the controller 18 will write the unwritten write request data to the disk array 26 as soon as possible if not immediately. This may provide the best response time since the amount of dirty data stored in the cache memory 33 will be kept at a minimum, thereby allowing cache memory 33 to be allocated quickly for new write request data. However, since dirty data will be retained in the cache memory 33 for a shorter period of time, fewer cache write hits (overwriting existing write request data stored in memory) will occur, and there will be less opportunity for concatenation and grouping of I/O requests thus causing more I/O accesses to the disk array 26 which degrades the performance of certain RAID levels. At a system shutdown and subsequent power down, all dirty data is quickly written to storage media, and battery 35 can be turned off thereby extending the battery life.
If the cache flush modifier parameter is set to fifteen (15), then the controller 18 will write the dirty or unwritten write request data to storage media only when there is a cache demand for new write request data. This may provide the lowest response time since dirty data stored in the cache memory 33 will be kept at a maximum, thereby causing new write requests to wait until other write request data has been written to storage media. Since dirty data will be retained in the cache memory 33 for a longer period of time, more cache write hits (overwrites) will occur and there will be more opportunities for concatenation and grouping of I/O requests thus causing fewer I/O accesses to storage media which improves the performance of certain RAID levels. At system shutdown and subsequent power down, the dirty write request data remains in cache, thus the battery 35 must be used to preserve the data thereby reducing battery life.
If the cache flush modifier parameter is set between zero (0) and fifteen (15), then schedule-driven cache flushing is indicated. That is, the controller 18 will flush the cache memory 33 in accordance with a particular time interval that is a function of the selected cache flush modifier parameter as shown in FIGS. 3A and 3B. The cache flushing time interval could relate exponentially to the cache flush parameter as shown in FIG. 3A, or could level out relative to the cache flush modifier parameter as shown in FIG. 3 B. Alternatively, the time interval could relate linearly to the cache flush modifier parameter. Thus, it should be appreciated that the time interval values shown in FIGS. 3A and 3B are only exemplary and can be modified accordingly. Further, it should be appreciated that each time interval vs. modifier relationship can be implement by a different cache flushing algorithm, and the different cache flushing algorithms can be selected in the cache flush algorithm field 72 . The cache flush modifier parameter is selectable on a per logical unit basis regardless of how the logical units are configured. Thus, if the controller 18 defines a number of logical units, each logical unit can have a different cache flushing modifier associated therewith.
The value specified in the two-minute warning flush algorithm field 76 is used to select a cache flushing algorithm to use when a UPS two-minute warning is received. The value specified in the two-minute warning flush modifier field 78 is used to provide cache flushing parameters to the controller 18 when a UPS two-minute warning is received. The two-minute warning flush modifier value indicates to the controller 18 the time interval to use for cache flushing if the “begin demand flush” threshold (discussed further below) is not reached. More specifically, the controller 18 uses the two-minute warning flush modifier parameter to select a time interval to use for cache flushing as described above with regard to the cache flush modifier parameter in field 74 .
Two additional host-selectable fields are used to implement demand cache flushing, namely, the demand flush threshold field 80 and the demand flush amount field 82 . The parameters specified in fields 80 and 82 are selectable on a global basis. In particular, if the controller 18 defines a number of logical units, then the demand cache flush parameters specified in fields 80 and 82 apply to each of the logical units.
As shown in FIG. 4, the demand flush threshold field 80 defines a selectable “begin demand flush” threshold 75 at which the controller 18 will begin to flush the cache memory 33 . The “begin demand flush” threshold 75 represents a particular amount of dirty data that is stored in the cache memory 33 . The “begin demand flush” threshold 75 is defined as a certain percentage of a “dirty maximum” threshold 77 , where the “dirty maximum” threshold 77 is a non-selectable, configuration-specific threshold that is governed by the amount of cache memory 33 that is allocated for storing dirty or unwritten write request data. The “begin demand flush” threshold 75 is specified as a ratio using 255 as the denominator and the value in field 80 as the numerator.
The demand flush amount field 82 defines a “end demand flush” threshold 79 at which the controller 18 will stop flushing the cache memory 33 . The “end demand flush” threshold 79 represents a particular amount or level of dirty data that will remain stored in the cache memory 33 after the controller 18 stops flushing the cache memory 33 . Once demand cache flushing begins, it will continue until the amount of dirty data stored in cache memory 33 falls below the “end demand flush” threshold 79 . Thus, the demand flush amount field 82 defines, in effect, the amount of dirty data that will be flushed by the controller 18 when a demand flush of dirty data occurs. The “end demand flush” threshold 79 is defined as a certain percentage of the “begin demand flush” threshold 75 , and is specified as a ratio using 255 as the denominator and the value in field 82 as the numerator.
In view of the foregoing, it should be appreciated that the cache memory 33 can be independently flushed based upon (1) the age of the dirty data stored in the cache memory 33 which is set by the cache flush modifier parameter in field 74 , and (2) the percentage of dirty cache stored in the cache memory 33 which is set by the “begin on-demand flush” threshold parameter in field 80 and the “end on-demand flush” threshold parameter in field 82 . Thus, it is possible that the cache memory 33 could fill-up with dirty data faster than the dirty data could age so that on-demand caching would take-over and flush the cache memory 33 . Likewise, it is possible that the cache memory would not fill-up with dirty data faster that the dirty data could age so that schedule driven caching would take over to flush the cache memory 33 .
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. | An apparatus and method is disclosed which enables a host computer to adjust the caching strategy used for writing its write request data to storage media during execution of various software applications. The method includes the step of generating a caching-flushing parameter in the host computer. The cache flushing parameter is then transferred from the host computer to a controller which has a cache memory. Thereafter, a quantity of write request data is written from the cache memory to a storage medium in accordance with the cache-flushing parameter. | 6 |
BACKGROUND OF THE INVENTION
This invention relates to an actuator assembly and more particularly, to an actuator assembly for converting linear movement to alternating clockwise and counterclockwise rotational movement.
A wide variety of actuators for converting linear movement to rotational movement have been developed and utilized in the past, typically for opening doors, operating locking mechanisms, etc., e.g., furnace doors, automobile vent windows, automobile heating and air conditioning duct doors, door locks, etc. These actuators generally include some type of linear motive means such as a vacuum motor and some type of gear arrangement, e.g., a worm gear assembly to convert the linear movement of the vacuum motor to a rotational movement which acts upon the door or the like which is to be moved through an arc or rotated. Clockwise and counterclockwise rotational movement is generally accomplished by changing the direction of linear movement of the vacuum motor, i.e., by reversing the motor. Although some of these actuators have been generally satisfactory, they have some disadvantages such as bulkiness, complicated linkages, unreliability, and high cost of manufacture. Accordingly, there is a continuing need for improved actuators to eliminate the above disadvantages.
SUMMARY OF THE INVENTION
According to the present invention, there is provided an actuator assembly for converting linear movement to rotational movement which is compact, reliable, and inexpensive to manufacture. The actuator is particularly adapted for operating the locking mechanism in an automobile door latch. The actuator assembly includes an elongated shaft and means as a solenoid and spring return means for producing linear movement of the shaft along its axial length in both directions and a rotatable member. Shiftable cam and cam follower means associated with the shaft and rotatable member are operable with linear movement of the shaft to produce alternating clockwise and counterclockwise rotational movement of the rotatable member. The direction of the rotational movement alternates after each cycle of axial movement of the shaft in both axial directions. The shaft is slidably mounted for linear movement along its length and has a transverse bore therethrough. A cam follower pin slidably received in the bore has a length slightly greater than the diameter of the shaft and is shiftable between a first position where one end of the follower pin operates the rotating member and a second position where the other end of the follower pin operates the rotatable member in the opposite direction. Preferably, a solenoid or a vacuum motor is used to produce axial movement of the shaft in one direction and a biasing means such as a coil spring is employed to urge the shaft in the opposite axial direction.
The rotatable member is positioned adjacent the shaft with its axis of rotation being generally perpendicular to the axis of the shaft. Abutment members extend upwardly from the rotatable member on each side of the shaft for engagement by the follower pin. The means for alternating the direction of rotational movement of the rotatable member includes a pair of arm members pivotally mounted adjacent the rotatable member. When the shaft is in a starting position in each cycle, one arm is in abutting contact at one end with the follower pin and at the other end with a camming surface on the rotatable member. The camming surface acts to alternately move the arms to shift the follower pin during each cycle of axial linear movement so as to alternately engage the abutment members after each cycle of linear movement of the shaft.
The actuator assembly is particularly adapted for use with a locking mechanism for an automobile door that includes a movable lock activator element. The actuator assembly converts linear movement to a rotational movement to move the lock activator element between locked and unlocked positions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the actuator assembly of the present invention;
FIG. 2 is an exploded perspective view of the actuator assembly of FIG. 1;
FIG. 3 is a side elevational view of the actuator assembly taken along line III--III of FIG. 1;
FIG. 4 is a simplified view of the bottom surface of the rotatable member and the arm members as viewed generally along the plane IV--IV of FIG. 3 with portions omitted for clarity;
FIG. 5 is an enlarged top plan view of the rotatable member;
FIGS. 6 through 12 are top plan views of the actuator assembly showing successive positions of the elements thereof during two complete cycles of linear movement of the shaft; and
FIGS. 13 and 14 are top plan views of the activator assembly showing successive positions of the lock activating mechanism during cycles of linear movement of the shaft.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 through 5 of the drawings, the actuator assembly of the invention is generally designated by the numeral 10 and includes an elongated rod-like first member or shaft 20 linearly movable with respect to a supporting framework 30. Shaft 20 cooperatively operates with a cam and cam follower assembly 40 to impart rotary motion to a rotatable member 50.
Actuator assembly 10 is adapted generally for mounting on an automobile door lock mechanism 60 (FIGS. 3, 13 and 14) to operate a lock activator element 62 to automatically lock and unlock door locking mechanism 60. Door lock mechanism 60 is of conventional design and may be of the type normally utilized in an automotive door assembly. Lock activator element 62 may be shifted manually as by a rod (not shown) extending through the automobile door casing into the interior of the vehicle or from the exterior as by a key or the like. The actuator of the present assembly is particularly adapted for use with door lock assemblies in a vehicle wherein the locks for the several doors of the vehicle may be simultaneously remotely operated by a single switch to allow the operator to effect locking or unlocking of all of the doors in the vehicle. In any of the several modes of operation, lock activator element 62 is shifted between the positions shown in FIGS. 13 and 14 to effect either locking or unlocking of door lock mechanism 60.
Shaft 20 is shifted between first and second positions to effect alternate clockwise and counterclockwise rotation of plate member 50 through each cycle of operation. Shaft 20 may be actuated to move along its linear axis by any motive means as a vacuum motor or the like. In the preferred embodiment shown, shaft 20 is actuated for movement along its linear axis by an electromagnetic coil 22. Coil 22 is of conventional construction comprising many turns of wire wrapped around a core 24 which may be molded as an integral part of frame 30. The wire ends (not shown) are connected to a suitable power supply through switch means (also not shown) in a conventional manner. Coil 22 and the core 24 may be mounted in a generally U-shaped solenoid frame 26 which conveniently may be formed as an integral part of bracket means (not shown) for mounting actuator assembly 10 to the lock mechanism 60.
Shaft 20 includes a first portion 28 slidably received in the center of core 24. Coil 22, core 24, and portion 28 of shaft 20 cooperatively form a solenoid. The first portion 28 of shaft 20 serves as the solenoid armature and upon electrical energization of coil 22 is caused to move inwardly along its linear axis to effect rotation of rotating element 50 as will be hereinafter described.
The opposite end of shaft 20 designated by the numeral 32 is generally D-shaped, having a flat bottom surface 34 formed thereon. Flat surface 34 extends along a portion of the length of shaft 20 where it forms a step 36 (FIGS. 1 and 4) midway along the length of the shaft. An opening 38 extends through shaft 20 about an axis transverse to the axial length of the shaft and is adapted to receive a follower pin 42. Follower pin 42 has a length slightly greater than the outer diameter of shaft 20 and its diameter closely corresponds to the diameter of the transverse bore 38 so that there is a slight friction fit. Follower pin 42 is slidably received through shaft 20 and may be shifted selectively to extend either side of the linear axis of shaft 20.
Support frame 30 is generally box-like in configuration having an open top, bottom wall 44, side walls 46-46a, and end walls 48 and 52. End walls 48 and 52 extend upwardly and are provided with openings 48a and 52a respectively formed therethrough to slidably receive shaft 20. Opening 48a slidably receives end 28 of shaft 20 while opening 52a is generally D-shaped in configuration having a flat bottom surface 54 to slidably receive the D-shaped end 32 and flat portion 34 of shaft 20. The corresponding D-shaped configurations of the shaft and opening 52a prevent rotation of the shaft with respect to frame 30.
A pair of mounting flanges 56 extend outwardly from side walls 46 and 46a each having an opening 58 therethrough by which the framework 30 can be secured to lock mechanism 60 in a conventional manner.
Bottom wall 44 has a series of three carefully spaced openings. A central opening 64 is adapted to receive a stud member 66 extending from the lower surface of rotatable member 50 and serves as a pivot mounting therefor.
The two additional openings 68 and 68a are equally spaced on each side of pivot opening 64 to receive pivot stud members 70 and 70a extending downwardly from a pair of arm members 72 and 72a respectively. An upwardly extending pin 74 fastened in bottom wall 44 is received in a radial recess 76 formed in the bottom surface of rotatable member 50. Pin 74 provides a stop means abutting the ends of radial recess 76 to prevent excessive rotation of plate member 50 as will be hereinafter described.
Arms 72 and 72a, rotatable member 50 and follower pin 42 cooperatively operate to form the cam and cam follower mechanism 40 to cause alternating clockwise and counterclockwise rotation of rotatable member 50 upon each cycle of operation of the actuator.
A circular depression or recess 77 formed in end wall 52 surrounds D-shaped opening 52a and forms a seat to relieve one end of a coil spring 78. Spring 78 is positioned over end 32 of shaft 20 and is retained thereon by a flanged cap member 80. Spring 78 serves as a biasing means to hold the shaft 20 in a first or neutral position (FIGS. 1, 3, 6, 9, 12, and 13). Magnetic forces generated in coil 22 when energized, shift shaft 20 to the left against the bias of spring 78. When a circuit through the coil is disconnected, spring 78 returns shaft 20 to the first position.
Rotatable member 50 is preferably molded from a plastic like material as polycarbonate. Member 50 is generally disc like and circular in shape. As described above, stud 66 extends from its lower surface and when positioned in opening 64, forms its pivot axis. As shown in FIGS. 4 and 5, stud 66 may have a configured lower surface for connection to a link member 82 (FIG. 3) having a pin 84 extending therefrom for reception in lock activator element 62 for effecting shifting movement thereof.
The upper surface of rotatable member 50 (FIG. 5) includes two upwardly extending abutment members 86 and 86a which, when assembled in the framework, extend upwardly on each side of shaft 20 for selective engagement by follower pin 42 with movement of the shaft. The outer diameter of rotatable member 50 is divided into two diameter portions, the first or larger outer diameter portion 88 includes the abutment members 86 and 86a. Sharply defined steps 90 and 90a at the abutment members 86 and 86a extend radially inwardly to form a smaller diameter portion 92. The steps extend along the length of the rotatable member to the bottom surface. Recess 76 formed in the lower surface of rotatable member 50 opens outwardly radially into the larger diameter surface 88. The larger outer diameter surface 88 forms a cam surface operable against the inner facing surfaces 94 and 94a of arms 72 and 72a respectively to cooperatively form a pair of cam followers.
Referring to FIGS. 2 and 4, arms 72, 72a are identical in shape but mirror images of each other. Each arm is slightly C-shaped, and as previously mentioned, is pivoted by means of pivot studs 70 and 70a in openings 68 and 68a formed in the bottom wall 44 of frame 30. Since arms 70 and 70a are identical, only arm 70 will be described in detail. The corresponding portion of arm 70a will be identified with a similar reference numeral with the suffix letter a when necessary. It will be noted that the inner faces 94 of arms 72 extend generally along the center line of pivot stud 70 exposing approximately one-half of the top surface of stud 70. A curved surface portion 96 forming a short leg of arm 70 has an inner surface radius approximately equal to the radius of the large outer diameter portion 88 of rotatable member 50. Surface 96 passes generally through the axial center of stud 70. The remaining longer leg portion of inner face 94 extends in the opposite direction from stud 70 where it forms an inwardly turned leg 100. The inner face (with respect to shaft 20) of leg 100 forms a ramp surface 102 extending upwardly to a flat surface 104. Ramp surface 102 and flat surface 104 form a second cam surface at the end of arm member 72 to operatively engage and shift follower pin 42 along opening 38 as will be hereinafter described.
Arm members 72 and 72a also may be molded of plastic like material preferably acetal or the like. Studs 70 and 70a are integrally formed with the cam surfaces and the inner faces of the arms. It will be noted that an exposed portion of the top of studs 70 and 70a extend outwardly from the inner face surface of the arms such that when the arms are inserted in openings 68-68a of frame 30, the exposed top surface of each stud is generally flush with the top surface of bottom wall 44.
It will be noted that the relative positions of openings 64, 68, and 68a and the configuration of the outer diameter portions 88 and 92 of rotatable member 50 are related to the curved inner face surface 96 and 96a of arms 72 and 72a. The center of openings 68 and 68a in which the studs 70 and 70a of arms 72, 72a are installed are located a distance from the center of the opening 64 in which stud 66 is mounted. This distance is equal to the largest radius of rotatable member 50. Curved surface 96 of the arms forms a cam follower surface for engagement with the diameter 88 of rotatable member 50. This curved surface 96 has a radius of curvature approximately equal to the radius of the larger diameter 88 of rotatable member 50 so that the cam surface 88 passes through the axial center line of studs 70 and 70a. The stepped surfaces 90 and 90a (FIGS. 4 and 5), as will be further described in the detailed description of the operation of the actuator, serve to selectively hold one or the other of the arms fixed during operation while allowing the other arm to pivot about the axis defined by the stud therefore allowing pin 42 to be shifted from one side or the other with movement of the shaft.
ASSEMBLY
Assembly of the actuator assembly is relatively simple. Arms 72 and 72a are positioned in frame 30 such that studs 70 and 70are pivoted in the corresponding mounting openings 68 and 68a, respectively. The lower surface of rotatable member 50 overlies the exposed top surface portions of studs 70 and 70a as the pivot stud 66 is positioned through opening 64 in the bottom wall of frame 30. Shaft 20 is inserted through the circular opening 48a in end wall 48 and pushed across rotatable member 50 between abutment members 86 and 86a. The shaft is then extended through the D-shaped opening 52a in end wall 52. Follower pin 42 is installed through opening 38 in shaft 20 by sliding the pin over a reduced height portion or notch 73, 73a on arms 72, 72a. Pin 42 is then shifted as required around the abutment members as shaft 20 is moved into position to receive coil spring 78 and cap 80. Coil spring 78 is positioned over the D-shaped end 32 of shaft 20 and is secured thereon by cap 80.
OPERATION
FIGS. 6 through 12 illustrate the operation of the various elements of actuator assembly 10. Referring to FIG. 6 rotatable member 50 is rotated to a full counterclockwise position and shaft 20 is biased to a first or outer position by spring 78. The outer diameter portion 88 of rotatable member 50 is in engagement with cam surface 96a formed on the inner face of arm 72a. Arm 72a is therefore pivoted such that flat area 104 engages shaft 20 and follower pin 42 causing the follower pin to extend through the opposite side of shaft 20 to extend outwardly toward arm 72. Shaft 20 is held in an outwardly biased position by spring 78. In FIG. 7 it is seen that as shaft 20 is drawn inwardly with actuation of the coil, shaft 20 acts as the solenoid armature and moves to the left against the bias of spring 78. Follower pin 42 engages the nearest abutment member 86 on rotatable member 50. As shaft 20 continues to move to the left, the engagement of follower pin 42 with abutment member 86 continues to rotate rotatable member 50 about stud 66 and into the position as shown in FIG. 8. Excessive rotation of rotatable member 50 is effectively stopped as pin 74 extending upwardly from bottom wall into recess 76 engages a sidewall of recess 76. As rotatable member 50 moves into this position, outer diameter surface 88 engages the curved cam follower surface 96 on arm 72 to lock arm 72 in position. At the same time the corresponding surface 96a on the opposite side at arm 72a, has disengaged and arm 72a is free to move.
In FIG. 9 coil 22 has been deenergized and bias spring 78 has urged shaft 20 to the right into its first position. Simultaneously with movement of shaft 20 to the right, follower pin 42 rides along the inner face 94 of arm 72 following along ramp 102 where it is urged upwardly to extend from the opposite side of shaft 20. Step 36 (FIG. 2) in shaft 20 engages the inner wall surface of the D-shaped cutout 52a at flat surface 54 to prevent shaft 20 from pulling out of frame 30.
As movement of shaft 20 and follower pin 42 rotates plate member 50, the inner surfaces of arms 72 and 72a and the outer diameter surface 88 act to shift and lock the arm 72 or 72a nearest the outer diameter portion of the rotatable member so that the ramp end 102 and flat area 104 of arm 72 in initial contact with follower pin 42, is urged toward shaft 20 while the other arm is displaced so that its end in initial contact with pin 42 is free to move away from the shaft as the return stroke is completed.
Spring 78 attached to the outer end of shaft 20 is forced into compression by the initial motion of the shaft and since it is biased against wall 52 of framework 30 it acts to pull the shaft back to its initial starting position when the coil is deenergized (FIG. 9). As spring 78 pulls shaft 20 back to its initial starting position, arm 72 on the side of the shaft 20 through which follower pin 42 is extending acts to push the pin through the shaft and out the opposite side from which follower pin 42 initially extended.
During the next cycle upon activation of the coil as shown in FIG. 10, a duplication of the above action occurs except that the oppositely mounted reciprocating parts move so as to return the arms, follower pin and rotatable member back to their original positions. In FIG. 11, for example, follower pin 42 has engaged abutment member 86a urging rotatable member 50 to rotate again in a counterclockwise direction. In FIG. 12 as spring 78 urges shaft 20 outwardly, follower pin 42 is urged to extend from the opposite side of shaft 20 for subsequent engagement with abutment member 86 as shown in FIG. 6.
During operation of the actuator of the invention, the importance of the previously described hole locations 64, 68 and 68a and the outer diameter surface 88 of rotatable member 50 and inner facing curved surfaces 96 and 96a of arms 72 and 72a is to effect an instant locking and unlocking of the arms into their camming and relaxed positions.
For purposes of discussion the camming position may be defined as that position in which either arm 72 or 72a will cause follower pin 42 to shift positions on either side of shaft 20. The instant change from the locked to unlocked position of arm 72 or 72a occurs at the time the step 90 or 90a of rotatable member is aligned with the center of stud 70 or 70a projecting downwardly from the respective arm. When step 90 or 90a of rotatable member 50 moves away from the center of the stud 70 in a direction toward the ramp surface 102, the arm is free to pivot and will not shift follower pin 42. As soon as step 90 crosses the center of stud 70 in the opposite direction, the arm can no longer pivot and is held in position against shaft 20 to cause displacement of pin 42 as it rides along ramp 102 and onto the flat area 104. When one of the arms is locked into position, the other arm is free to pivot. During operation, if for some reason shaft 20 or rotatable member 50 is stopped during movement and neither arm 72 or 72a is locked, no jamming will result. As the coil is deenergized, shaft 20 will return to its initial position and follower pin 42 will remain protruding from the same side of shaft 20 as at the beginning of the stroke. Neither arm will have any biasing influence on pin 42 so that as the coil is again energized, the mechanism will complete the stroke not previously completed.
Those skilled in the art will readily recognize that the present invention provides an actuator assembly which is of simple construction and extremely reliable in operation. Those so skilled will also readily appreciate the many advantages of the present invention and will recognize the many modifications which may be made. While a preferred embodiment of the invention has been described and illustrated in detail, it is intended that the equivalent arrangements be covered unless the following claims by their wording expressly state otherwise. | An actuator assembly for converting linear movement to rotational movement for operating a lock assembly for locking and unlocking doors and the like. The assembly includes an axially shiftable shaft, a rotatable member associated with the shaft alternately rotatable in clockwise and counterclockwise directions with axial movement of the shaft, and cam and cam follower means for reversing the direction of the rotational movement of the rotatable member after each cycle of axial movement of the shaft. | 8 |
This is a continuation of co-pending application Ser. No. 821,492 filed on Jan. 22, 1986 and now abandoned which is a continuation in part of Ser. No. 315,576 filed on Oct. 27, 1981 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the preparation of a natural fertilising material. More particularly, this invention relates to a method and a plant for preparing an essentially sterile fertilising material from waste sewage sludge.
It is well known that before waste sewage sludge can be used for agricultural or horticultural purposes, essentially complete sterilisation of such sludge is required because of the particular contents of the sludge, which may contain parasites, viruses, bacteria, and the like. Without some or other sterilisation process being applied to the sludge, the danger of propagation of and/or subsequent contamination and infection by parasites and disease precludes the free use of such sludge for agricultural or horticultural purposes.
Since human faeces carry virtually all human and animal infections and parasites, it is a prerequisite for the substantially unrestricted use of such a natural fertilising material in agricultural or horticultural applications that the sludge is suitably treated by a sterilisation process in order to produce a safe fertilising material.
2. Description of Related Art
It is known to those skilled in the art that waste sewage sludge is often matured after treatment thereof in a sewage plant for sterilisation purposes. Such maturation is carried out either by leaving a pile of waste sewage sludge exposed, in which case fungus may form on the surface thereof; or a pile of sewage sludge may be placed under a layer of, for example, grass sods, in which case natural processes lead to the generation of heat in the pile of sludge. Both these maturation processes usually take several weeks before the sludge may be recognised as being suitable for use as a natural fertilising material. Whilst these natural processes take a considerable period, which is a disadvantage in terms of throughput or production of such natural fertilising material, these processes do not invariably rid the sludge of undesiragble parasites, viruses, bacteria, and the like, and give rise to the loss of nitrogen due to volatilisation, which results in a lower nutrient value in the product.
In contrast to the above natural methods, it is also known to those skilled in the art that sewage effluent may be treated by means of exposure to chlorine gas, the sludge in this case being in suspension, i.e. at a very high moisture content. Such methods, and for example filtration followed by break-point chlorination, can clearly not be applied to sludge. It has been reported that even such treatment cannot guarantee inactivation of all the organisms present.
U.S. Pat. No. 3,445,383, dated May 20, 1969, to Roland J. Horvath et al. teaches a process for treating sewage effluent with chlorinated glycolurils in order to achieve slow release of chlorine to provide long term disinfection of sewage effluent. Essentially, however, this amounts to treatment of sewage effluent with chlorine, and this method, as pointed out above, cannot guarantee a sterile product.
In 1975, Smith, Young and Dean (Water Research, Vol. 9, pp. 17-24) proposed a process of aerobic thermophyllic digestion, or so-called "wet composting", to sterilise sewage sludge, but the method does not seem to have been widely adopted, probably because of its high cost.
The presently accepted methods for ensuring the destruction of pathogens present in sludge usually involve the application of heat. It is generally accepted that Ascaris ova, considered to be the most resistant of the organisms present in sewage and therefore an indicator of the efficacy of a treatment method, are destroyed when subjected to a temperature of at least 60° for a minimum period of 30 minutes (B.D. Hays, Water Research, Vol. 11, pp. 583-95, 1977). In Germany and Switzerland, sludge intended for land application is generally treated in this manner; use of such heat sterilisation is, however, considered too expensive a procedure for most other countries. As a result, large quantities of sewage sludge infected by pathogens have been accumulating in many countries, particularly on the fringes of urban areas, where they constitute a continuous health hazard, without their soil nutritional values being utilised.
Another recently developed technique which is currently applied for the sterilisation of sewage effluent and of sludge is the process of radiation, which involves particularly the use of gamma rays or of electrons of relatively low energy (i.e. velocity). Plants using gamma ray sterilisation are generally very expensive and have a modest throughput.
Methyl bromide has been used routinely over many years for fumigating soils prior to the planting of crops sensitive to insect pests and organisms such as nematodes, or in the preparation of seedbeds. In such applications the methyl bromide is injected into the soil under an impervious cover (to prevent escape of the methyl bromide into the atmosphere) at ambient temperature in the form of the liquid and/or as the vapor.
In the United States Department of Agriculture Publication No. E-838 entitled "Methyl bromide fumigation of cotton seed in freight cars for the destruction of pink bollworms" by G.L. Philips the use of methyl bromide vapor is discussed for killing pink bollworm larvae embedded in cotton seed when exposed to moderate concentrations of methyl bromide. In U.S. Pat. No. 4,200,656, Cohen et al describe a method for fumigating grain stored in bins by a gravity penetration method comprising applying a mixture of carbon dioxide and methyl bromide. All insects were killed throughout the total depth of the bin. In a control experiment using methyl bromide alone, only insects in the upper part of the bin were killed.
The fumigation techniques taught by these references, however, fall short of sterilisation, i.e. they do not mention Ascaris ova nor do they suggest that they could be effective against Ascaris ova.
In the Textbook of Parasitology by David L. Belding (third edition), on pages 468 and 469, mention is made that Ascaris and Toxocara ova in infested soils are killed by the use of free iodine, and green or root vegetables from gardens fertilised by night soil can be safely used after treatment with free iodine. It is also stated that treatment of infested soil by means of agricultural and other chemicals, for example chlorthion and isochlorthion, is claimed to kill the ova.
Belding (on p. 469 of his book) quotes K. Enigk and J. Eckers (Zentrallbl. Bakt. Abt. 1 Orig. Volume 179, pp. 397 -432, 1960) as having found that "gaseous dibromethane" "rapidly" kills Ascaris ova in soil. Of course, there is no compound known in English by this name. Reference to the original paper by Enigk and Eckers shows that, while the English Summary accompanying the paper uses the term "dibromethan", the compound should correctly have been translated from the German text as dibromoethane. Belding therefore used a wrong term, which we repeated unchanged in the specification of our prior copending U.S. application Ser. No. 315,567, now abandoned, and which we interpreted at the time as meaning dibromomethane.
In their experiments Enigk and Eckers sprayed the liquid dibromoethane (of boiling point 131,4° C.) by means of a garden insecticide spray on to the surface of experimental patches of soil which were artificially infected with Ascaris ova. At soil temperatures of 20°-21° C. the application of 100-200 ml/m 2 of surface area of this compound produced essentially complete eradication of Ascaris ova up to a depth of 20 cm, but at lower soil temperatures and/or application rates the efficacy of the treatment was considerably reduced.
Although Belding in his book makes no reference to it, we have now noted that the Enigk & Eckers paper also reports experiments (aimed at finding an effective disinfectant to destroy Ascaris ova in soil) with pressurised liquid methyl bromide, applied to the top of the experimental patch of soil through a small number of pipe nipples located in an impervious cover placed over the soil. The authors report that methyl bromide was tested on surfaces of 25 to 45 m 2 in quantities of 22,2 to 44,4 ml/m 2 , but showed no reliable effect in that the Ascaris ova were killed only in the immediate vicinity of the nipples, whereas in positions some distance away from the nipples the effect was small or the treatment failed completely.
Thus these references teach that the use of organic bromo compounds such as dibromoethane and methyl bromide as a means of killing Ascaris ova in soils, will meet with limited success. Efficient eradication was observed only up to a few centimeters deep from the surface of the soil, and in some cases only in the vicinity of the point of application of the chemical. In fact, Enigk and Eckers teach away from the invention, in that they specifically state dibromoethane to be more successful in eradicating Ascaris ova than methyl bromide, and in that they teach that methyl bromide "showed no reliable effect" (cf their English Summary on p. 427 of the paper). We now suspect that the failure of their experiments to produce more reliable results with methyl bromide is almost certainly due to the fact that they applied the methyl bromide, at least partially, in the form of the liquid directly from the pressurised container, as would appear to be suggested by the photograph appearing on p. 405 of their paper, which has the caption : "Abb. 1 Desinfektion des Erdbodens mit Methylbromide. Das Methylbromid stroemt aus einer Stahlflasche durch einen Einfullstutzen unter die Kunststoffplane", which may be translated as: "FIG. 1. Disinfection of the ground with methyl bromide. The methyl bromide flows out of a steel bottle through a filling nipple under the plastics cover. " The fact that they express the amounts of methyl bromide applied per m 2 of ground in millilitres further corroborates this interpretation. It is suggested by the applicant, with the benefit of hindsight derived from his own invention, that the methyl bromide, when applied in this manner, would fully permeate the surface of the ground before it could spread laterally to achieve a uniform distribution in the horizontal plane. Dibromoethane, because of its high boiling point, can only practically be applied by spraying the liquid; the high boiling point also makes it safe to do so without a cover (in contrast to methyl bromide), making it possible to observe the application of the chemical and ensure that it is uniformly applied.
The results of Enigk and Eckers are, in any case, not applicable to the treatment of sewage sludge, as it is not obvious whether the organic bromo compound vapor would produce a similar degree of penetration in the sewage sludge compared to soil, having regard to the differences in particle size, density, compaction and moisture content of the two materials.
Despite the great need for an efficient treatment method of reasonable cost that will eradicate Ascaris ova in sewage sludge, thereby to effectively sterilise the sludge, and thus to make it available as a natural fertiliser material, the use of methyl bromide has not been reported.
SUMMARY OF THE INVENTION
Applicant has now surprisingly found, directly contrary to the teachings of the prior art concerning the eradication of Ascaris ova in soils, that Ascaris ova can be effectively eradicated in sewage sludge, thereby essentially sterilising said sewage sludge, by applying heated methyl bromide in the form of a vapor to the top of a bed of sewage sludge preferably not exceeding about 1 meter in depth and covered by a sheet or cover which is impervious to the vapor, by allowing said vapor to permeate the bed of sewage sludge under the force of gravity over a period of approximately 48 hours, provided the moisture content of the sewage sludge does not exceed about 35 percent by mass. (The term "vapor" used in this specification is to be taken as having the strict scientific meaning of a clear gas, free of droplets of liquid, i.e. consisting of the gaseous phase only.)
According to the invention there is provided a method of preparing natural fertilising material, including the step of contacting waste sewage sludge, having a relatively reduced moisture content, with methyl bromide, applied in the form of vapor, for a period sufficient to effectively sterilise the sludge, thereby producing a natural fertilising material from the sewage sludge.
The expression "relatively reduced moisture content" when used herein means that the waste sewage sludge is readily or sufficiently permeable by the vapor. In practice the upper limit to the moisture content satisfying these requirements has been found to be approximately 35%.
The method includes the steps of introducing the vapor at the top of a body of sewage sludge to be treated and permitting the vapor to permeate the body of sewage sludge downwardly under the force of gravity.
A supply of pressurised liquid methyl bromide may be provided from which methyl bromide vapor is drawn off. Preferably the methyl bromide liquid is heated so as rapidly to convert the pressurised methyl bromide liquid into vapor, which is contacted with the sewage sludge. In the preferred embodiment the methyl bromide vapor is almost invariably hot. The term "hot" must here be broadly defined. Preferably it is meant to describe the temperture of the methyl bromide vapor issuing from a pipe manifold connected to a heating coil, the other end of the coil being connected to a pressurised supply of liquid methyl bromide, and the coil being immersed in a bath of hot liquid, preferably boiling water. Depending on the length of the heating coil, the temperature of the liquid which covers the heating coil, ambient conditions, the position of an orifice on the pipe manifold, etc., the temperature of the methyl bromide vapor issuing from an orifice in the pipe manifold may be between 100° and ambient temperature, preferably between 95° and 40° C. Of course, if so desired, yet a higher temperature may be ensured by using a nonaqueous liquid in the heating bath which has a boiling point substantially higher than that of water. Examples of such liquids are high-boiling oil fractions, glycerine and high molecular-weight organic esters.
It is an important feature of the invention that the methyl bromide is fully vaporised at the heater, i.e. all the necessary latent heat of vaporisation is supplied here, and the vapor is distributed through the pipe system or manifold(s) from whence it issues from orifices freely (i.e. not sprayed from nipples) at a sub-critical pressure drop. This assures that there will be no condensation (due to adiabatic cooling associated with a super-critical pressure drop), and hence lateral distribution before penetration of the bed.
The minimum amount of methyl bromide required for effective sterilisation during the minimum treatment period indicated is about 50 grams per cubic meter of sludge. In practice, the higher the moisture content of the sludge and the lower the ambient temperature, the larger the amount of methyl bromide and/or the longer the treatment period required. Since the cost of the methyl bromide constitutes only a modest proportion of the overall cost of preparing the natural fertilising material, a larger amount of methyl bromide, for example 100 to 200 g/m 3 , preferably 100 to 400 g/m 3 , can be utilised to assure complete sterilisation.
The method may include the step of providing the sewage sludge in a trough spread into the form of a bed, preferably by means of a suitable conveyor means.
The method may include the step of removing the sewage sludge after sterilisation thereof from the trough by means comprising a worm conveyor.
The bed may have a thickness not exceeding about 2 meters, preferably being about 1 to 2 meters, more particularly being about 1 meter.
The method may further include the step of first reducing the moisture content of the sewage sludge to less than about 35% before contacting it with methyl bromide vapor. The reason for this is that if the sludge has a moisture content higher than about 35%, the gas permeability thereof decreases substantially with increasing moisture content, and any vapor permeation or diffusion process may take considerably longer, and/or a considerably larger amount of methyl bromide may be required, to achieve a satisfactory sterilisation of the sewage sludge.
The contact period of the methyl bromide vapor with the sewage sludge may be between 36 and 72 hours, being preferably about 48 hours.
If the moisture content of the sewage sludge is considerably lower than 35%, the contact time may be proportionally less than 48 hours.
The method includes the step of providing a layer or sheet of impervious material sealably above a sewage sludge body, for the duration of a treatment cycle, and introducing the methyl bromide vapor in a gas-tight manner to the space between the layer of impervious material and the body of sewage sludge.
Also according to the invention, there is provided a plant for preparing natural fertilising material, comprising at least one trough adapted for receiving waste sewage sludge to be sterilised, a methyl bromide vapor supply, and a pipe system connected to the methyl bromide vapor supply and located above the bed and adapted to introduce to and suitably contact waste sewage sludge when received in the or each trough with the methyl bromide vapor.
The plant includes an impermeable cover sheet provided sealably over the or each bed and enclosing the pipe system, to prevent escape of the methyl bromide vapor to the atmosphere.
The plant may include heating means adapted to vaporise pressurised methyl bromide liquid and to supply the methyl bromide in the form of vapor to the or each bed.
It is possible to take off methyl bromide vapor directly from a pressured container, i.e. without converting the liquid into vapor by means of a heated coil, but in such a case the vapor becomes cooled to substantially below the ambient temperature, because of the take-up of heat from the environment to supply the heat of vaporisation of the liquid methyl bromide. Such cooled methyl bromide vapor may possibly not spread laterally as uniformly as hot vapor, to cover the entire surface area of the bed of sewage sludge, in the initial stages of the treatment cycle entailing the risk that those portions of the bed surface furthest away from the inlet openings may not receive the desired dose of methyl bromide vapor, hence leading to incomplete sterilisation of portions of the bed of sewage sludge. Such a risk is greatest when the ambient temperature is relatively low, the moisture content of the sludge is relatively high, and the dose of methyl bromide is below 100 g/m 3 . Vaporisation of the methyl bromide in a heated coil in accordance with the preferred embodiment of the invention not only minimises this risk, but speeds up application of the methyl bromide vapor to the top of the bed of sewage sludge.
Since methyl bromide vapor, which is essentially odorless, is dangerous to humans and animals, it is preferable to use a blend of 98% methyl bromide and 2% chloropicrine, as is known in the art. This latter compound has an extremely pungent smell, which therefore acts as a safety factor in alerting a worker to a possible leak of methyl bromide vapor.
The methyl bromide sterilising fluid may also include one or more volatile compounds which together provide a broader sterilisation spectrum or an intensified sterilisation effect. Thus the methyl bromide may contain for example any other known volatile sterilising compound, for example a germicide, an insecticide, and/or an acaricide, applied together with the methyl bromide or separately therefrom.
The heating means may comprise a heating gas supply, a gas burner and a water bath located operatively above the gas burner, the water bath having located therein a heating coil for vaporising the methyl bromide liquid, the heating coil being connected at its one end to the supply of methyl bromide liquid and at its other end to the pipe system.
The pipe manifold may be upwardly hingeable to permit filling of the or each trough with sewage sludge and optionally to permit removal of the sewage sludge after sterilisation thereof.
The plant may include suitable sludge handling equipment for filling the or each trough with sewage sludge prior to the sewage sludge being contacted with the methyl bromide vapor, and optionally for removal of sterilised sewage sludge. The sludge handling equipment may include at least one conveyor belt for filling the or each trough with sewage sludge. Preferably the conveyor belt is a roving conveyor belt. The base of the trough may be wedge-shaped and a conveyor worm may be located at the base thereof for removal of sewage sludge after sterilisation thereof.
The or each bed of sewage sludge may have a depth not exceeding about 2 meters, being preferably about 1 to 2 meters, more particularly about 1 meter. The or each trough may have any convenient width and length. A trough accommodating a bed of sewage sludge of dimensions 50 meters long by 6 meters wide by 1 meter deep is typically a convenient size.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example, with reference to the following drawings, in which:
FIG. 1 shows a side sectional view of a plant for producing natural fertilising material, in accordance with the invention,
FIG. 2 shows a partial sectional plan view on the section line II--II of the plant shown in FIG. 1, and
FIG. 3 shows a schematic diagram of a methyl bromide vapor supply layout for the plant shown in FIGS. 1 and 2.
DETAILED DESCRIPTION OF THE INVENTION
Referring firstly to FIGS. 1 and 2, reference numeral 10 refers generally to a plant for producing natural fertilising material according to the invention. The plant 10 comprises two troughs 12 and 14 respectively located adjacent each other and constructed of a common concrete floor slab 16, and brick and mortar dividing wall 18.
The troughs 12 and 14 are covered by a weather-proof roof covering 20 supported by a plurality of supports 20.1, 20.2 suitably anchored in concrete footings in the ground, as shown in FIG. 1.
The troughs 12 and 14 ae shown filled with beds of sewage sludge 22 and 24 respectively. The trough 14 has a pipe manifold 26 located at or near the top of the trough 14.
The inlet 26.1 of the manifold 26 is connected to a methyl bromide vapor supply (to be discussed more fully hereunder) and each branch member or pipe 26.2 is blanked off at its free end, and has a plurality of spaced openings (or orifices) therein (not shown) for permitting introduction of the methyl bromide vapor from the manifold 26 to the top of the bed of sewage sludge 24.
The bed of sewage sludge 22 in the trough 12 has already been sterilised, and the troughs 12 and 14 are used in rotation to ensure a more or less steady production rate.
The manifold inlet 26.1 may be attached to the methyl bromide liquid supply (not shown) by a swivel joint (also not shown) to enable the manifold 26 to be hinged upwardly from the trough 14 to permit ready loading of sewage sludge into the trough 14 for sterilisation thereof.
A conveyor belt (not shown), preferably of the roving type, may be provided for transport of matured sewage sludge from for example an adjacently located sewage works to the plant, and more specifically to the troughs 12 and 14. Naturally the plant may comprise a plurality of troughs 12 and 14, depending upon production requirements.
Whilst the troughs 12 and 14 have the particular shape shown by the section in FIG. 1, each trough may be provided with a wedge-shaped base and a conveyor worm located at the base of the wedge for removal of sterilised sewage sludge.
The depth of each trough 12, 14 is approximately one meter.
An impermeable cover sheet in the form of a plastics sheet 28 is provided over the bed of sewage sludge 24 in trough 14 to prevent escape of methyl bromide vapor to the atmosphere. The plastics sheet 28 is therefore sealed along all four of its sides to the trough 14.
Referring now to FIG. 3, reference numeral 30 refers generally to a pressurised methyl bromide liquid supply which may be used in conjunction with the plant 10 and which may be considered as a part thereof.
The sterilising fluid supply 30 comprises a scale 32 which may be used for weighing a cylinder 34 of liquid methyl bromide from time to time. The cylinder 34 has a supply valve 34.1 to which is connected a pipe 34.2 which in turn is connected to a heating coil 36 located in a water tank 38. The opposite end of the coil 36 is in turn connected to a pipe 40 having a control valve 40.1 therein, as well as a pressure gauge 40.2. The pipe 40 then continues and is connected to the inlet 26.1 of the manifold 26, as explained above.
A cylinder 42 of heating gas is connected via a supply valve 42.1 and a supply pipe 42.2 to a burner 44 located below the water tank 38 for heating the water in the tank 38.
In use the plant is operated as follows:
Waste sewage sludge from a sewage works that has received the conventional sewage treatment, and which is otherwise considered to be a sewage end product, is dried by any conventional means or allowed to dry naturally, if required, until a moisture content of less than approximately 35% has been attained in the sludge.
The sewage sludge, if or when sufficiently dry, is transported to and loaded into the trough 14 as shown in FIG. 1 preferably by means of a conveyor (not shown), to form a bed 24. Sludge 22 in trough 12 has already been sterilised, and the sterilised sewage sludge 22 therein is awaiting removal.
The pipe manifold 26 is then positioned as shown in FIG. 1, and the manifold pipe 26.1 is connected to the methyl bromide vapor supply pipe 40.
During loading of the sewage sludge 24 into the trough 14, the manifold 26 may conveniently be swung hingeably and upwardly away from the trough 14. When the trough 14 has been filled with sewage sludge 24, the manifold 26 is lowered so that it is positioned on top of the bed 24, as shown in FIG. 1.
Conveniently the belt conveyor, mentioned above, is used for transporting and loading the sludge into the troughs 12, 14.
A suitable plastics sheet 28 is then placed over the bed 24, as shown in FIG. 1, so that the trough 14 and bed 24 are effectively sealed in a gas-tight fashion.
With the manifold part 26.1 connected to the methyl bromide supply pipe 40, the supply valve 42.1 on the heating gas supply cylinder 42 is opened and the burner 44 is lit. The heating gas flows along the pipe 42.2 and is ignited outside the burner 44, thereby heating the water in the water tank 38, preferably to boiling.
The control valve 34.1 on the methyl bromide cylinder 34 is then opened, and methyl bromide liquid is allowed to flow along the pipe 34.2 into the heating coil 36 where under the influence of the hot or preferably boiling water in the water tank 38 the methyl bromide liquid is vaporised and converted into vapor. The methyl bromide vapor then flows along the pipe 40, and when the control valve 40.1 is opened, the methyl bromide vapor flows along the pipe 40 into the manifold pipe 26.1, and into the branch pipes 26.2 where the methyl bromide vapor escapes from the branch pipes 26.2 via the openings provided therein (not shown). Since methyl bromide vapor at all tempertures from ambient to 100° C. has a density greater than air, the vapor tends under the influence of gravity to permeate or diffuse downwardly through the body of sewage sludge 24. Since the trough 14 and bed 24 are effectively sealed in a gas-tight fashion, the methyl bromide vapor cannot readily escape therefrom.
The branch pipes 26.2 are made up, for example, of suitable plastics piping having a diameter of about 50 to 60 mm. The holes therein are about 4 to 5 mm in diameter and are provided about every 150 mm along the length of each branch pipe 26.2. To account for the Bernoulli effect, the size of the holes are progressively increased along the length of a pipe towards the blanked off end.
After the contact period the plastics sheet 28 is removed, the pipe manifold 26 hinged upwardly away from the trough 14, and the sterilised sewage sludge 24 removed from the trough 14. By that time, the already sterilised sewage sludge 22 in the trough 12 would have been removed and the trough 12 would be refilled by another batch of sewage sludge to be treated. The troughs 12 and 14 are therefore used in rotation to ensure a more or less steady supply of sterilised sewage sludge.
EXAMPLES
It has been found by the inventor that methyl bromide, when introduced to the bed in the form of vapor in accordance with the invention, surprisingly effectively destroys viruses, parasites, bacteria and other micro-organisms which occur ordinarily in sewage sludge.
In the examples below, different batches of sewage sludge, each filling a trough having a depth of approximately one meter, a width of six meters and a length of fifty meters, were treated using varying quantities of hot methyl bromide vapor and treatment periods of varying duration. The ambient temperture during these runs varied between about 15° and 30°. The microbiological analyses reported below were carried out by the Cape Regional Laboratory of the National Institute for Water Research of the South African Council for Scientific and Industrial Research in Bellville, Cape Town, whose representatives were present during the conduct of the experiments and who also carried out the sampling.
Table 1 records the results of the microbiological analyses of sewage sludge at Scottsdene Sewage Works, Kraaifontein, near Cape Town, before and after the treatment. The treatment was carried out in June 1980.
Table 2 reports further results, obtained in early 1984, for treatment runs with sewage sludge at the Scottsdene Sewage Works, as well as at at the sewage works of Upington, in the Northern Cape Province. Representative random samples were taken in each case according to established sampling techniques. In each case the methyl bromide liquid was volatilised and heated by immersing coil 36 in boiling water.
The results show that, in the Scottsdene plant, all Salmonella and viable Ascaris ova were eradicated at all the values of moisture content tested. At the Upington plant, an application rate of 100 g/m 3 of hot methyl bromide vapor destroyed all E. coli, colifage and Salmonella in the sewage sludge.
The treated sewage sludge obtained in the earlier run at Scottsdene analysed as follows:
______________________________________% N 4,4 % Loss on ignition 58.5% P 1,0 pH 5,9% K 1,1 % Na 0,11% Moisture 34,0______________________________________
showing it to be a useful natural fertilising material of high plant nutrient content.
Naturally in this specification and claims when mention is made of effective sterilisation, this implies that sterilisation is effected not necessarily totally but to a degree acceptable, for example by local health authorities, for application of such fertilising material for agricultural and/or horticultural purposes.
Routine or spot bacterial and other testing may be carried out on the sewage sludge either during or after sterilisation, and such testing may form part of the sterilisation method.
Although certain embodiments of the invention have been described above, it will be readily apparent to those skilled in the art that the scope of the invention is not to be considered limited by these embodiments, and that there are numerous variants and modifications of the invention possible which fall within the scope of the following claims.
TABLE 1______________________________________Results of microbiological examination ofuntreated and treated sewage sludge atScottsdene Sewage Works on 17th June 1980.Dose: 50 g of methyl bromide per cubic meterTime of treatment (duration): 48 hours Confirmed Viable Coliforms E. coli Ascaris Colifage (37°) per (44°) per ova per 10 g g dry dry per 100 drySample material material counted material______________________________________1. Untreated 3.4 × 10.sup.8 4.9 × 10.sup.7 6 4.2 × 10.sup.4 dried activated sludge2. Treated 8.1 × 10.sup.6 0 0 0 sludge (sampling point - North)3. Treated 9.8 × 10.sup.6 0 0 0 sludge (sampling point - middle)4. Treated 8.4 × 10.sup.6 0 0 0 sludge (sampling point - South)______________________________________
TABLE 2__________________________________________________________________________Results of Microbiological Examination of Untreated (control) andTreatedSewage Sludge at Scottsdene and Upington Sewage Works, during firstquarter of 1984 Total Coliforms E. Coli ASCARIS OVASample Duration of Moisture (37° C.) (per Colifage Salmonella (per 100 g dry)Sample Descrip- MeBr.sup.# dose Treatment Content (per 100 g) 100 g (per 100 (qualita- Non-No. tion (g/m.sup.3) (h) (%) dry) dry) g dry) tively) Viable Viable__________________________________________________________________________ S1* Control -- -- -- 4.6 × 10.sup.8 0 0 + 84 636S2 Pile 1 200 72 22.1 3.3 × 10.sup.8 0 0 - 0 114S3 Pile 2 200 72 35.4 6.4 × 10.sup.9 0 0 - 0 191S4 Pile 3 200 72 42.7 4.1 × 10.sup.9 0 0 - 0 998S5 Pile 4 200 72 28.5 7.0 × 10.sup.9 0 0 - 0 128S6 Pile 5 200 72 17.1 2.2 × 19.sup.9 0 0 - 0 562 U1** Control -- -- -- 5.0 × 10.sup.6 1.0 × 10.sup.6 3.6 × 10.sup.4 + 0 0U2 Batch 1 50 48 9.6 2.0 × 10.sup.6 1.0 × 10.sup.5 2.1 × 10.sup.2 + 0 0U3 Batch 2 100 48 8.9 4.0 × 10.sup.6 0 0 - 0 0__________________________________________________________________________ *S = Scottsdene sludge **U = Upington Sludge .sup.# = Methyl bromide | A method and plant are provided for sterilizing waste sewage sludge with methyl bromide vapor, to produce a natural fertilizing material. The moisture content of the sludge is reduced to a level where the vapor permeability of the sludge is sufficiently high to reduce the contact period of the methyl bromide vapor with the sludge to an economically viable level. The methyl bromide is provided at a dose of at least 50 g/m 3 to the top of a bed of sewage sludge having a moisture content of less than 35% and about 1 meter thick and allowed to permeate the bed over a period of about 48 hours under the force of gravity, the bed of sewage sludge being covered during the entire treatment period with a cover which is impermeable to the methyl bromide vapor. Harmful pathogens and parasites such as Ascaris ova are effectively eliminated. | 8 |
The present invention relates to an improved process for performing start-up of a partial oxidation gas generation system comprising a refractory lined gas generator and a gas purification system. In the improved process of the present invention, a sulfur-free, liquid organic fuel is employed during start-up and pressurizing of the gas generator. As a result, gases normally vented or flared to the atmosphere have reduced levels of contaminants.
BACKGROUND
Various fossil fuels contain components other than hydrogen and carbon, such as sulfur. Combusting such fuels may emit objectionable amounts of gaseous sulfur compounds into the atmosphere. For example, petroleum, coke, coal and heavy residue from hydrocarbon refining processes often contain relatively high contents of sulfur and nitrogen compounds. In addition, some liquid and gaseous fuels contain relatively large amounts of sulfur compounds. Such liquid fuels, while unsuitable for use directly in furnaces, may be processed to remove objectionable components. Solid fuels are generally more difficult to process to remove undesirable sulfur and nitrogen compounds and are less convenient to transport than liquid and gaseous fuels.
It is well known that various carbonaceous fuels (i.e., fossil fuels) may be converted to reducing gas, fuel gas, or synthesis gas (syngas) comprising carbon monoxide and hydrogen by partial oxidation at an elevated reaction temperature and pressure. In these processes, a fossil fuel, such as coal, is reacted with an oxygen-containing gas, usually commercially pure oxygen, in a closed, compact reactor at an autogenous temperature within a range of about 1000° to 1600° C. The reaction zone is usually maintained at a pressure above about 100 pounds per square inch gauge (psig) and may be as high as 3000 psig; usually the process reaction pressures during steady state operation are in the range of 200 to 1200 psig. Steam may be introduced into the reaction zone to assist in the dispersion of fuel in the reactor. Steam also assists in control of the reaction temperature and acts as a reactant thereby decreasing the amount of free oxygen required in the process.
It is also well known that synthesis gas mixtures comprising carbon monoxide and hydrogen are important and useful commercially for a number of reasons. For example, synthesis gas has been used for many years as a source of carbon monoxide in carbonylation reactions. A method for producing such mixtures of gases, which has been used commercially for decades, is by the partial oxidation of sulfur-bearing hydrocarbon fuel; generally, coal in the form of a slurry, which yields a product gas comprising CO, CO 2 , H 2 and H 2 S.
Fuel burners for producing synthesis gas by partial oxidation of a coal slurry are known. See, for example, U.S. Pat. Nos. 3,758,037 and 3,945,942, which relate to a multitube burner assembly and a process for its use.
The gases produced from gasifying a fossil fuel such as coal may be, and preferably are, further processed to separate them and remove by-products. This is accomplished by gas purification and processing systems known in the art. For example, the product gas from a gasifier may be processed to remove CO 2 and H 2 S to levels of 1-2 ppm. The removed H 2 S may be further processed to convert it to its elemental form in a sulfur recovery plant; the CO 2 may also be captured and/or further processed. After removing CO 2 and H 2 S, the remaining gas primarily contains CO and H 2 (i.e., syngas). The syngas is most often sent directly to downstream plants for further processing into useful derivatives, such as acetyl chemicals like acetic acid and acetic anhydride.
Under steady state conditions in a typical partial oxidation gas generation plant, the coal gasification process makes syngas and the gas purification system minimizes emissions of contaminants. However, because of the nature of the processes (gas streams instead of liquid, wide temperature extremes, and high pressures), the processes must be started in sequence. The gasifier is started first and must be started instantly at a 50% rate because the burner within the gasifier cannot "turn down" past 50%. Since the product gas from the gasifier cannot be stored, it must be vented and burned at a flare stack until the gas purification process (i.e., the gas clean-up process) can be pressurized, cooled down, and started up.
In a conventional start-up of a partial oxidation gas generating process the gas generator is started at atmospheric pressure after preheating to at least 950° C. Until the gasifier is pressurized and downstream processes brought on-line the resulting effluent, comprising syngas, is burned in a flare. As is well known to those skilled in the art, this results in higher than normal emissions of contaminants such as sulfur. See, for example, U.S. Pat. No. 4,385,906; see also U.S. Pat. No. 3,816,332.
Thus, it is well known to those in the art that start-up of a partial oxidation gas generator presents special challenges, including contaminant emissions. For example, U.S. Pat. No. 4,378,974 to Petit et al. discloses a start-up method for a coal gasification plant, in particular a refractory lined rotary kiln. The method of Petit et al. focuses on the problems that arise from coal having a high chlorine content. In Petit's reactor, the lining is made of materials susceptible to chlorine-induced cracking in the presence of oxygen. Petit starts the reactor up in stages while maintaining an oxygen content in the reactor of a sufficiently low level to prevent chlorine-induced cracking of the refractory lining.
In addition, U.S. Pat. No. 4,385,906 to Estabrook discloses a start-up method for a gasification system comprising a gas generator and a gas purification train. The method of Estabrook isolates and prepressurizes the gas purification train to 50% its normal pressure; the gas generator is then started, and its pressure increased before establishing communication between the generator and the purifier. Purified gases from the purifier may then be burned in a flare until all parts of the process reach appropriate temperature and pressure.
We have found that air contaminants, such as sulfur, which are characteristic of start-up, may be eliminated by starting the gasifier on a sulfur-free, liquid organic fuel. In our unique process, a gasifier is started using a sulfur-free liquid organic fuel; once the appropriate conditions of temperature and pressure are attained in the gasifier and gas purification systems, the burner is transitioned to a carbonaceous fossil fuel slurry.
A number of factors must be considered before determining the appropriate liquid to use in the improved process for starting a partial oxidation gas generator. Those considerations included:
1. Fuel Considerations
a) oxygen to fuel ratio must be similar (on volume basis) as that present when the coal slurry is fed to the gas generator.
b) Resulting gas composition should have similar CO/H 2 /CO 2 ratios so that downstream plants can operate within their designed parameters.
c) The liquid fuel should be compatible with slurry since both will use common equipment during transition.
d) The liquid fuel should be "clean" and free of substances that are not normally present such as high concentrations of metals.
e) Atomization differences between the two fuels on the same burner.
f) Gasifier dynamics such as flame temperature, refractory wear, pressure build-up.
g) Fuel availability, cost, health and safety hazards.
2. How to transition from liquid fuel to slurry without interrupting the feed system.
3. How to start-up sulfur recovery plant at low H 2 S concentrations before the system is lined out.
As set forth in more detail below, the sulfur free liquid organic fuel may be a hydrocarbon compound of 1 to 20 carbons.
It is an object of the present invention to provide a process for start-up of a partial oxidation gas generator that minimizes contaminants such as sulfur.
It is a further object of the invention to provide a start-up procedure that does not require raw syngas derived from a fossil fuel to be flared and vented to the atmosphere.
It is also a further object of the invention to provide an alternative process for preheating a partial oxidation gas generator that does not require a natural gas source.
BRIEF DESCRIPTION OF THE DRAWINGS
The attached FIGURE sets forth an embodiment of an apparatus and equipment for use in the present invention.
SUMMARY OF THE INVENTION
A process for starting up a partial oxidation gas generation system comprising a refractory-lined pressurized gas generator and a gas purification system which comprises the steps of:
a) preheating the gas generator;
b) introducing a sulfur-free liquid organic fuel and an oxygen-containing gas into the preheated gas generator;
c) allowing the pressure inside the gas generator to reach a pressure of 100 to 3000 psig, and the temperature to reach 1000° to 1600° C.;
d) diverting a product gas comprising CO and H 2 produced in the gas generator to the gas purification system; and
e) replacing the sulfur-free liquid organic fuel with a carbonaceous fuel.
As will be discussed below, the process may also be used to preheat the gas generator (i.e., step a) above) with the sulfur-free liquid organic fuel. Further, the process may be employed when more than one partial oxidation gas generator is present.
DETAILED DESCRIPTION OF THE INVENTION
In a conventional start-up of a partial oxidation gas generation process, the gas generator is first preheated to ensure the integrity of the refractory lining upon start up and during operation. The gas generator is then started up at atmospheric pressure and the resulting effluent gas from the gas generator burned in a flare. Once the gas generator is pressurized and operating satisfactorily, the flow of gases from the gas generator is diverted to the gas purification system, and eventually to downstream processes once the purification system is fully pressurized. As the pressure in the system increases, the volume of gases passing from the gas generator to the gas purification system may be increased until full pressure and throughput conditions are reached.
Likewise, if there are downstream processes that will use product gas from the purifier, those processes must be pressurized as well; until downstream processes are pressurized, and normal flows and equilibria established, purified syngas is vented and flared at the purifier. It will be understood that the product gas is normally burned at the flare only during the startup period.
More specifically, the start-up requires that the gas generator's reaction zone first be preheated to a temperature of about 950° to 1300° C. at substantially atmospheric pressure. Preheating is accomplished by burning a clean fuel gas, most typically natural gas (methane), with an oxygen containing gas; the products of this combustion (carbon dioxide and water) are vented to the atmosphere.
Usually, the preheating operation requires use of a rather simple burner suited to the methane fuel. Once the gasifier is preheated, the natural gas burner must be removed and the coal slurry burner introduced into the gas generator prior to start-up; at least some temperature loss is inevitable because of this change over. It should be understood, that the sulfur-free, liquid organic fuel may also be employed to preheat the gasifier. This would accomplish at least two things: eliminate the need for a source of natural gas and eliminate the extra step of changing burners between preheating and start up.
In a conventional start-up, a carbonaceous fuel such as coal slurry is fed to the reactor with an oxygen containing gas; the mixture immediately ignites in the high temperature environment. Under the process of the present invention, a sulfur-free, liquid organic fuel rather than a coal slurry is introduced into the gas generator once the generator is preheated and the burners changed.
As noted above, we have discovered that start-up emissions may be eliminated by starting the gasifier on a sulfur-free, liquid organic fuel. In our unique process, a gasifier is started using a liquid fuel that does not contain sulfur; once the appropriate conditions are attained in the gasifier and gas purification systems, the burner is transitioned to coal slurry.
The appropriate liquid fuel may broadly be described as a liquid hydrocarbon compound, or a mixture of such compounds, free of sulfur and having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. For example, the hydrocarbon compound may be an alcohol, preferably an aliphatic alcohol of 1 to 12 carbon atoms such as methanol, ethanol or propanol. Among aliphatic alcohols, propanol is preferred; and most preferably n-propanol.
In addition, a relatively clean organic waste or low value stream (i.e., that results from other processes) that is free of sulfur, has 1 to 20 carbon atoms, and that is compatible with a water/coal slurry may serve as an alternative. Waste or low value streams that are outside of these criteria are also possible, but have more risk and will require a more cautious testing program.
Referring now to the FIGURE, once the gas generator has been preheated, the sulfur-free, liquid organic fuel is fed to the gas generator. For purposes of the following description, the sulfur free liquid organic fuel will be propanol (for example, n-propanol). The propanol is fed from tank 1 through line 2 to centrifugal pump 3, and through remotely operated valve 4. Pump 5 is a specialized, positive displacement pump designed to pump coal slurry. Prior to and during start-up, propanol is pumped through valve 4 and through pump 5 and into line 6. Before propanol is introduced into the generator (i.e., during preheating), it is circulated back to tank 1 to establish flow in the lines. Thus, remotely operated valves 7 and 8 on line 9 are closed so that the propanol is diverted into line 11 via valve 10. Further, valve 13 is closed so that the propanol is sent through valve 12 and into line 14, and finally back into tank 1.
Once the generator is preheated, the burners changed, and the circulation of the propanol established, valves 7 and 8 are opened, and valve 10 closed, allowing propanol to flow through line 9 and into gas generator 23 where it is mixed with oxygen and burned. The resulting effluent gas, as noted above, is vented and flared at valve 21. Under the process of the present invention, unlike processes known in the art, the flared gas is free from pollutants that are characteristic to fossil fuels (i.e., sulfur).
Almost immediately after the propanol fuel is ignited, flare valve 21 is restricted and pressure built up within the gas generator to the desired level. At full pressure within the gas generator, the gas is slowly diverted from flare valve 21, to valve 22, into the gas purification process 25 and out flare valve 27. This is continued until flare valve 21 is completely closed. The product vented and flared at the purification system at valve 27 is substantially comprised of clean syngas. Once valve 21 is completely closed, the propanol feed is switched to coal slurry. Thus, valves 17 and 19 are opened and coal slurry allowed to pass through lines 18 and 20 and into pump 5 with propanol; consequently, valve 4 is closed off. For a short time, the lines leading to the gas generator contain both propanol and coal slurry. The coal slurry then passes through lines 6 and 9 and into the gas generator, which burns the coal slurry in place of the propanol start-up feed. Once the fuel has changed from propanol to coal slurry, the oxygen flow is adjusted to match the required amount for coal slurry. When the downstream processes are brought on line, the product gases are no longer flared through valve 27.
The gasifier start up process normally takes 2-4 hours, but can take longer if the coal gasification process (i.e., the facility) has been down for a long time.
A sulfur recovery plant, which may be placed downstream of the gas purification system, must start-up on natural gas only. After the purifier is on line and fully operating, the operator must slowly reduce the flow of natural gas, increase the sulfur-containing process gas from the purifier and adjust the amount of air fed into the recovery plant as the concentration of the H 2 S builds.
In a particular embodiment of a gasifier process, the gasifier uses a "three-stream" burner, having oxygen in the center, coal slurry in an annulus surrounding the oxygen, and oxygen again in an outer annulus. An example of a coal that may be used typically originates in Southwest Virginia or Kentucky, which has a sulfur content of approximately 2.5%. Coal of any origin may be used, but it is generally preferable that the coal have a low melting point, high carbon content and low ash content. The gasifier is typically operated during steady state at about 1400° C. and about 1,000 psig pressure. The product gas is cooled to near ambient temperature and sent to downstream processing, including purification (to remove CO 2 and H 2 S) and sulfur recovery. The cleaned syngas is then further processed in reactions for which syngas serves as a raw material.
The process of the present invention may also be used when more than one gasifier is present. Occasionally, a new gasifier is started before the old one is shut down, which is called a gasifier "switch." During a switch, the flow of product gasses to the downstream processes remains uninterrupted. The basic procedure described above is the same except for the following: the new gasifier is started on propanol and pressurized as described above; the old gasifier (rates reduced, but still on line and burning coal slurry) is then switched to propanol. Flare valves are switched so that the output of the old gasifier is being flared and the new one is brought on line (i.e., all output from the new gasifier is being sent to the purifier). The old gasifier is then shutdown. The new gasifier is then switched to slurry.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications will be effected within the spirit and scope of the invention. | Coal gasifiers using technology developed by Texaco Development Corporation, use coal slurry and oxygen as feed stocks. During start-ups, the raw gas produced in the gasifier must be flared until the downstream clean-up and recovery plants can be started. In order to reduce emissions through the flare during start-up, a technique was developed to start the gasifiers and downstream plants on a sulfur free, liquid, organic fuel. Once downstream plants are on-line, the fuel feed is switched to coal slurry on the same burner. The switch is accomplished while maintaining pressure and without interrupting to the fuel feed. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This Application claims priority to U.S. Provisional Application No. 61/595,561 filed Feb. 6, 2012 and is incorporated herein in its entirety by this reference.
FIELD OF THE INVENTION
[0002] This invention relates to down hole drilling assemblies, and more particularly, to a down hole tool to prevent overpressure scenarios for down hole drilling motors or surface pumping equipment to achieve higher rate of penetration while still maintaining drilling motor pressures within the motor or surface equipment specifications.
BACKGROUND
[0003] Coiled tubing drilling requires the use of a down hole positive displacement motor (PDM) to rotate the drill bit. During drilling operations, the unloaded PDM rotates at a constant RPM and achieves a free spin motor pressure with respect to the fluid flow rate. As the drill bit encounters the bottom of the hole and forces are transferred to the bit, referred to as (WOB), the motor will register an increase in torque. This increase in torque is a result of increased resistance to rotating at the constant RPM assuming a constant flow rate of drilling fluid. In return, the PDM requires additional pressure to turn the motor at the constant RPM while under increased resistance. If the resistance increases to a condition which prohibits the PDM from rotating, a motor stall is encountered. During a motor stall, the motor stops turning, the down hole fluid path is severely restricted, and the surface pump pressure dramatically increases. This event can eventually cause a motor failure, which requires the drilling process to be stopped.
[0004] Time constraints and the resultant daily operational costs are always a consideration for any down hole drilling operation. High drilling rates of penetration (ROP) coupled with minimal delays results in a highly desirable, cost-effective operation. Overly optimistic drilling rates of penetration in difficult formations place undue strain on sensitive down hole motors and can lead to premature failure of the rubber stator. These failures are expensive and time consuming as they require additional trips to surface as well as motor replacement.
[0005] A tool specifically designed to prevent over pressure scenarios for down hole drilling motors having a rotor and a stator arrangement would allow operators to achieve higher rates of penetration while still maintaining drilling motor differential pressures within manufacturer specification. Such an improvement would have tangible results in the pursuit of a highly efficient and cost-effective operation. In order for a down hole tool to protect a drilling motor from over pressure scenarios it must also be able to maintain differential pressures within manufacturer specification, regardless of operator input parameters controlling the rate of penetration. Consequently, a need exists for a down hole tool which can protect the drilling motor from over pressure scenarios while simultaneously allowing the motor to operate within manufacturer specifications. The present invention provides a down hole tool to achieve this objective.
SUMMARY OF THE INVENTION
[0006] The present invention comprises a down hole tool, also referred to herein as a motor saver sub, for use in a down hole drilling assembly near the bottom of the tubing near a positive displacement motor and the drill bit. In one embodiment, the tubing comprises a reel of coiled tubing, although the invention can also be used in rotary drilling applications. The motor saver sub operates in two distinct modes, namely normal operation and overpressure prevention. These two modes are controlled by four hydraulic valves acting together to effectively open a circulation port to drilling annulus at a high pressure setting and close the circulation to annulus at a low pressure setting. During the overpressure prevention mode, the circulation rate of the drilling fluid does not have to be reduced or cease in order for the system to reset back to normal operation which is closed to annulus when the overpressure condition expires. The motor saver sub has been designed to allow the operator to maintain the optimum drilling and hole cleaning pump rate while the tool resets itself, a feature not found in other down hole pressure limiting devices. Another feature of the present invention is that during the overpressure prevention mode, not all drilling fluid is diverted to annulus. A certain percentage of the centerline fluid, based upon the pressure requirement of the motor, will continue to pass through the bit and out to annulus. The act of opening the fluid flow path to annulus during the overpressure prevention mode allows the motor saver sub to control the motor differential, or delta, pressures and maintain them within drilling motor manufacturer specifications, thus preventing premature damage to any components of the motor.
[0007] The motor saver sub includes four hydraulic valves which include two field adjustable valves, one fixed setting valve and one control valve. The two adjustable valves control the high and low pressure settings for switching between the two operational modes of the tool. The fixed setting valve is an annular circulation port which controls down hole delta pressure. The control valve processes the pressure signals from the adjustable pressure setting valves and opens or closes the annular circulation port which is the fixed setting valve.
[0008] During normal drilling operations, average acceptable motor delta pressure range from 300 psi unloaded to a maximum pressure while drilling of approximately 1500 psi. To ensure that the pressure stays within drilling motor manufacturer guidelines, the low and high pressure adjustable valves should be set within an acceptable delta pressure range, for example 500 psi to 1400 psi respectively. The fixed setting valve for the annular circulation port would have any pressure setting above the low pressure and below the high pressure adjustable valve settings, and for this example could be 700 psi.
[0009] A first drilling motor operating range would be motor free spin, a result of pumping fluid while the drill bit is off bottom and rotating freely. A normal free spin motor delta pressure would be 300 psi. A second operating range for the motor is during normal drilling operations. The motor rotates the drill bit and as the bit is forced down hole, interaction with open hole formation causes rotational frictional losses reacted on the drill bit face which in turn increases the torque required to turn the motor. The rubber stator in the motor can only handle so much torque and pressure before damage. This normal drilling range is usually 400 psi to 1500 psi. A third operating pressure range during drilling operations is overpressure. When the torque requirement to turn the drill bit as it interacts with the formation increases past normal operating pressures, the rubber stator is subjected to excessive forces from pressure buildup from the rotating rotor. As the work required to turn the drill bit increases, the drilling motor rotor can actually stop rotating, or stall. As this point there is no longer any flow path for the pump fluid to exit to annulus and the pressure builds exponentially. This can cause irreparable damage in a short period of time necessitating a trip to surface to replace.
[0010] The motor saver sub of the present invention is designed to operate in conjunction with the drilling motor in these various pressure ranges. During free spin or normal drilling operations of the motor, all drilling fluid passes through the motor saver sub and through the drilling motor. During overpressure operation the annular circulation port through the fixed setting valve is opened to reduce motor pressure. Fluid flow path through the motor is still available. The motor saver sub is able to reset itself without manipulation of the drilling circulation rate by a control valve which operates based upon pilot signals received from the high pressure setting valve and the low pressure setting valves.
[0011] These and other aspects of the invention, including additional embodiments, will be more fully understood by reference to the following detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic view showing a down hole assembly containing a tool to prevent overpressure conditions for down hole drilling motors according to principles of this invention;
[0013] FIG. 2 is a cross-sectional schematic view of the tool of FIG. 1 ; and
[0014] FIG. 3 is a schematic hydraulic diagram of the tool of FIG. 2 .
DETAILED DESCRIPTION
[0015] FIG. 1 is a schematic diagram illustrating a coiled tubing drilling system 10 for drilling a well bore in an underground formation 12 . The coil tubing drilling system can include a coiled tubing reel 14 , a gooseneck tubing guide 16 , a tubing injector 18 , coiled tubing 20 , a coiled tubing connector. 21 , and a drill bit 22 at the bottom on the well bore. The drilling system also includes a control cab 24 , a power pack 26 and an assortment of other bottom hole assembly tools at 27 . This arrangement is all well-known in the art. During drilling, the down hole equipment includes a down hole motor 28 , such as a positive displacement motor for rotating the drill bit 22 . A down hole tool 30 specifically designed to prevent overpressure scenarios for drilling motor 28 is positioned along the coiled tubing adjacent the motor 28 . The tool 30 to prevent overpressure scenarios for the drilling motor and will also be referred to herein as a motor saver sub. The motor saver sub has been designed to prevent overpressure scenarios while allowing drilling system operators to achieve higher rates of penetration while still maintaining drilling motor delta pressures within the motor manufacturer specifications. The motor saver sub protects the drilling motor while enabling the motor to maintain delta pressures regardless of operator input parameters controlling the rate of penetration.
[0016] Also referring to FIGS. 2 and 3 , the motor saver sub 30 has two modes of operation, namely, normal operation and overpressure prevention operation. These two modes are controlled by four hydraulic valves 32 , 34 , 36 and 38 . These four hydraulic valves act together to effectively open a circulation port 40 to the well bore annulus 42 , shown in FIG. 1 , at a high pressure setting, and close off the circulation of drilling fluid to annulus at a low pressure setting. During the overpressure prevention mode of operation, the circulation rate of the drilling fluid does not have to reduce or cease in order for the tool to reset back to normal operation (closed to annulus) when the overpressure condition expires. The motor saver sub 30 has been designed to allow the operator to maintain the optimum drilling and hole cleaning pump rate while the tool resets itself. During the overpressure prevention mode, not all drilling fluid is diverted to annulus. A certain percentage of the center line fluid, based upon the pressure requirements of the motor will continue to pass through the drill bit before entering the annulus. The act of opening the fluid flow path Co annulus during overpressure prevention allows the motor saver sub to control the motor delta pressures and maintain them within drilling motor manufacturer specifications thus preventing premature damage to the motor.
[0017] The four hydraulic valves of the motor saver sub comprise two field adjustable valves 32 , 34 , one control valve 36 and one fixed setting valve 38 . The two adjustable valves control the high and low pressure settings for switching between the two operational modes of the tool. The fixed setting valve 38 is an annular circulation port which controls down hole delta pressure. The control valve 36 processes pressure signals from the adjustable pressure setting valves 32 and 34 and opens/closes the fixed setting valve annular circulation port 38 .
[0018] During normal drilling operations, average acceptable motor delta pressure range from 300 psi unloaded to a maximum pressure while drilling of around 1500 psi. To ensure that the pressure stays within drilling motor manufacturer guidelines, the low and high pressure adjustable valves 32 and 34 should be set within the acceptable delta pressure range, for example 500 psi and and 1400 psi respectively. The annular circulation port 38 would have any pressure setting above the low pressure adjustable valve setting, for example 700 psi.
[0019] The drilling motor operates within 3 ranges. The first range is motor free spin which results when a pump 44 pumps drilling fluid through the motor while the drill bit 22 is above the bottom of the formation and rotating freely. A normal free spin motor differential pressure would be 300 psi. The second motor operating range occurs during normal drilling operations. The motor rotates the drill bit and as the bit is forced down hole, interaction with the open hole formation causes rotational friction losses reacted on the drill bit face which in turn increases the torque required to turn the motor. Normal drilling range is usually between 400 psi and l500 psi. The third pressure operating range for the drilling motor is overpressure.
[0020] The motor saver sub 30 is designed to operate in conjunction with the drilling motor in the three pressure ranges. In the first range during free spin, the low pressure setting valve 32 is in a closed position 46 and does not provide a pilot signal 48 to the control valve 36 . The high pressure setting valve 34 is in a normally open position 50 and sending a pilot signal 52 to the control valve 36 . The high pressure valve pilot signal 52 plus the spring force 54 act on the control valve to maintain the control valve in a normally open position 56 . The normally open position of the control valve ensures that the annular circulation port stays in a closed position 58 . When drilling ahead within the normal operating range of the motor, the low pressure valve 32 will shift to an open position 60 which supplies the pilot signal 48 to the control valve. The high pressure valve will also be supplying the pilot signal 52 to the control valve as normal pressures are below the high pressure valves pressure setting. In this case, the control valve position will remain in its normally open position 56 because the pilot force on 62 on one side of the spool is negated by the pilot force 64 on the other side of the control valve. The only additional force exerted on the spool of the control valve is the spring force 54 which maintains the valve in the normally open position 56 .
[0021] The final pressure range is overpressure and is any pressure greater than the setting of the high pressure valve 34 . In the event of a spike in circulating pressure, usually indicative of a motor stall, the high pressure valve will shift to its closed position 66 and stop sending a pilot signal 52 to the control valve. The control valve will then shift to the close position 68 as the force imbalance of the pilot pressure 62 acting on the low pressure valve side overcomes the spring force 54 on the high pressure valve side. As the control valve ceases to provide a pilot signal 70 to the annular circulation port fixed setting valve 38 , the annular circulation port valve will then move to an open position 72 in the same manner as the control valve via a left side/right side force imbalance. The sudden redirection of fluid from the high pressure drilling motor to the low pressure annular circulation port will immediately reduce the down hole differential pressure from 1400 psi to 700 psi and signal the operator that an overpressure scenario has been averted.
[0022] Annular circulation port controlled pressure indicates that action needs to be taken. Upon interpretation of the feedback signal provided by the motor saver sub, the operator would then cease running in hole and begin the process of picking the drill string off bottom of the well. The motor saver sub reacts as the down hole differential pressure deceases due to the opening of the annular circulation port fixed setting valve 38 . The down hole differential pressure established by the stall/heavily loaded drilling motor and the open annular circulation port fixed valve must not trigger the control valve to shift back to its normally open position. Due to the design of the control valve, the pilot signal 52 from the high pressure valve during the annular circulation port fixed valve controlled pressure is ignored when the control valve is in the closed position 68 which is the overpressure range. This feature is necessary because if the control valve were to shift during the annular circulation port control pressure, the system would reset and result in instability of the annular circulation port opening/closing.
[0023] The proper timing for the motor saver sub to reset is when the low pressure valve shifts back to its normally closed position 66 indicative that the motor is unloaded and free spinning. This feature is accomplished by the control valve pilot area 74 on the high pressure valve side being positioned in a larger non-sealing area 76 when in the closed position 68 . If no seal around the high pressure valve pilot area is present, the signal has no pressure area to react upon resulting in zero pilot force. In this unique situation, the pilot signal 48 from the low pressure valve controls the position of the control valve and maintains it in the closed position 68 until loss of the low pressure valve pilot signal. As the operator continues to pick the bottom hole assembly off bottom, the annular circulation port maintains 700 psi of pressure on the bottom hole assembly while the drilling motor is still loaded. Once the interaction of the formation on the drill bit ceases, the required port and resultant pressure would decrease back to motor free spin or 300 psi. As the drilling motor begins free spinning, the annular circulation port and low pressure valve would shift back to the normally closed position 58 and 46 respectively. The closing of the low pressure valve would halt the pilot signal 48 to the control valve. The control valve would then move back to its normally open position 56 as a result of a force imbalance on the spool provided by the spring 54 and no opposing pilot forces. This result in drop in pressure from the annular circulation port induced pressure (700 psi) to motor free spin pressure (300 psi) is the second feedback signal to the operator indicating that normal drilling operations can recommence. The motor saver sub is then fully reset and ready for additional motor protection cycles without manipulating drilling and hole cleaning pump rate.
[0024] One particular embodiment of the present invention is designed for rotary and coiled tubing drilling operations. A range of sizes from 2⅛″ to 10″ can be achieved to meet a particular application. A specific motor saver sub can have a 4.75″ tool outside diameter, a 2.0″ tool inside diameter, is 22″ in length and has a flow rate of 0-10 BPM. The materials used in a motor saver sub include various corrosion resistant and erosion resistant materials. Stainless alloys are used in the tool joints and housing of the tool. MP35N or Eligiloy is used for the valve spring. Tungsten carbide is used in the valve spools and bodies. Seals are made from commercially available elastomers that are fit for down hole use.
[0025] The motor saver sub of the present invention may be installed in a bottom hole assembly as a single component or it may be used with other components in addition to the down hole motor and drill bits including milling bits, tractors and nozzle and circulation subs as commercially available from BJS Services, Schlumberger, Halliburton, Baker Hughes, and Weatherford. For example, the motor saver sub can be used in conjunction with a down hole tractor to aid in CT drilling operations in connection with a down hole tractor. The tractor can be as described in U.S. Pat. No. 7,343,982 which is used to move down hole equipment in the bore. When an overpressure situation occurs, the motor saver sub would effectively shut off the tractor and allow the operator to pick the bottom hole assembly off the bottom and restart drilling operations.
[0026] Features and benefits of the present invention include during free spin or normal drilling operations all drilling fluid passes through the drilling motor. In an overpressure condition, the annular circulation port opens to reduce motor pressure however drilling fluid continues to flow through the motor. The tool resets itself without manipulation of the drilling circulation rate. The control valve is a non-symmetrical pilot area for operation of the control valve and the motor saver sub has been designed with uni-directional engineered leakage to better tolerate drilling fluid and associated debris in hydraulic control systems.
[0027] Although the present invention has been described and illustrated with specific embodiments thereof, it is to be understood that the invention is not to be so limited as changes and modifications can be made which are within the full intended scope of the invention as hereinafter claimed. | A down hole drilling tool for preventing overpressure strain on surface pumping equipment or a down hole drilling motor having a housing and a circulation port and four hydraulic valves positioned on the housing actively working together to affectively open the circulation port to drilling annulus at a high pressure setting and dose the circulation port to annulus at a low pressure setting, the four hydraulic valves include a high pressure setting valve, a low pressure setting valve, a control valve and a fixed setting valve. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to radio frequency power delivery, and more particularly to the detection and avoidance of arcing in radio frequency powered plasma processes.
2. Brief Description of the Prior Art
Radio frequency (RF) powered plasma processes are commonly used in the manufacture of semiconductors, flat panel displays, data storage devices, and in other industrial applications. While RF power supplies are typically well protected against sudden changes in load impedance, they generally are not designed to detect and respond to changes in plasma impedance caused by arcing within a process chamber. As a result, an RF power supply may continue to feed energy into incipient arcs that develop within a plasma process, which in turn may cause serious damage to the surface of a workpiece or even to the processing equipment itself.
In DC powered plasma processes, the problem of arcing has long been studied, particularly in reactive sputtering applications. In a reactive sputtering process, arcing often results from charge buildup and eventual electrical breakdown on the surface of dielectric films deposited on the sputtering target or chamber walls. Problems of arcing in DC plasma processes have been addressed by through the use of sophisticated arc handling systems capable of detecting arcs and of employing any number of techniques to mitigate their severity, such as temporarily interrupting power or reversing the polarity of output voltage. In critical applications, the time during which the output voltage is removed is taken into account to adjust processing time so that the total energy delivered to the plasma is controlled and limited. In DC systems, it has also long been recognized that pulsing the DC output or reversing the output polarity at a certain repetition rate and duty cycle can reduce the tendency of arcs to develop.
RF power has been seen as an alternative technology that may be used to sputter an insulator directly while avoiding altogether the arcing problems in DC sputtering processes. Only recently has it been recognized, however, that occasional arcing occurs in RF processes as well, and that for sensitive film properties or geometries this RF arcing can be equally as damaging. Arcing in RF powered systems may result from charge buildup across gate-electrode patterns on semiconductor wafers or upon polymer coatings on chamber surfaces. Other factors include defects in the reactor or chamber hardware, degradation of the protective chamber anodization layer, differences between the electrical potential across tool parts, or even simply the magnitude of the RF power being applied. In any event, handling and avoidance of arcing requires the capability of both rapidly detecting the onset of an arc and rapidly interrupting or removing the output power so as to reduce the energy delivered into the arc.
In one approach, arc detection and avoidance in RF systems has been based upon establishing a predetermined threshold of a power delivery parameter, such as reflected power. The occurrence of an arc is inferred from a sudden rise or spike in reflected power that exceeds the predetermined threshold. This approach is not effective, however, while the power transfer of the system is being tuned, i.e., before the reflected power of the system has been brought to a steady state value that is below the predetermined threshold. The threshold approach is also limited in that arcing in an RF processing application does not always lead to an increase in reflected power. Depending on the state of the match network, an arc may in fact reduce the reflected power, and therefore not trigger an arc detection in a simple threshold circuit.
Another approach to RF arc detection correlates the derivative, or time rate-of-change, of a power delivery parameter to an arcing condition. Some RF arcs may develop slowly, however, over a period of 1 microsecond or longer, and may therefore go undetected by a derivative detector. Moreover, the derivative detector has increasing gain with frequency up to a point where practical limitations restrict the bandwidth. As a result, the derivative detector becomes more sensitive to noise at higher frequencies of operation.
SUMMARY OF THE INVENTION
This invention provides methods and systems for detection and reduction of arcing in RF power delivery applications. In one aspect of the invention, an RF power generator applies power to a load, such as a plasma in a plasma processing system. A dynamic boundary is computed about the measured value of a parameter representative of or related to the power transferred from the power generator to the load. A subsequently measured value of the parameter that exceeds the computed dynamic boundary of the parameter indicates detection of an arc. Upon detection of an arc, power delivery from the generator is interrupted or adjusted, or other action is taken, until the arc is extinguished.
In one embodiment of the invention, a plasma processing system comprises an RF power generator that furnishes power through an impedance matching network to a plasma load. Instantaneous values of reflected power between the generator and load are measured, while the match network is tuning as well as during fully tuned, steady state power delivery. A boundary comprising upper and lower values of reflected power about the measured value is computed dynamically and evaluated by a controller circuit. If a subsequently measured value of reflected power exceeds either the upper or lower boundary limit, the occurrence of an arc is indicated. The controller circuit interrupts power from the generator to the load for a brief interval to quench the arc. If the reflected power has fallen back within the boundary limits, normal power delivery is resumed.
In other embodiments of the invention, any one of a number of available power delivery parameters or signals is used alone or in combination for detection of arcs in RF powered plasma systems. In addition to reflected power, dynamic boundaries of the invention are computed based upon measurements of parameters including, but not limited to, load impedance; voltage, current and phase; forward power, delivered power, VSWR or reflection coefficient; magnitude level variations in the harmonic output; DC bias developed on a process workpiece or target; changes in the RF spectrum harmonics or acoustic interferences; or variations in ion saturation currents, electron collision rates, or electron densities within the plasma.
In another embodiment of the invention, an RF power delivery system employs parallel arc detection circuitry. A slow-filtered measurement of a power delivery parameter is used in to compute dynamic arc detection boundaries, in conjunction with one or more user-selected constants that determine sensitivity of the detection circuitry. A fast-filtered value of the power delivery parameter is compared to the computed detection boundaries in order to detect occurrence of an arcing condition. In this way, a flat pass band is created between the cut-off of the slow filter and the cut-off of the fast filter. As a result, optimal sensitivity can be maintained over a range of input frequencies as compared for example to arc detection based upon derivative techniques.
By employing dynamic computation of arc detection boundaries, the invention allows for arc handling in RF power deliver systems regardless of whether the system has reached a stable power delivery condition. Continuous monitoring and handling of arcing events in RF applications allows for improved process quality and throughput with better yields.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a plasma processing system in accordance with one embodiment of the invention.
FIG. 2 illustrates a process and circuitry for arc detection and handling in an RF power delivery application in accordance with one embodiment of the invention.
FIGS. 3 a and 3 b illustrate detection and handling of arcing in an RF power delivery application in accordance with one embodiment of the invention.
DETAILED DESCRIPTION
FIG. 1 illustrates a plasma processing system in accordance with one embodiment of the invention. Processing system 10 comprises RF power generator 12 that delivers RF power through impedance matching network 14 to a plasma 16 within plasma chamber 18 . Instantaneous values of forward power P F and reflected power P R are measured at the output of generator 12 and communicated to control logic 20 , which controls a disconnection circuit at the output of power generator 12 .
FIG. 2 illustrates a process and circuitry for arc detection and handling in an RF power delivery application in accordance with one embodiment of the invention. Measurements of forward power P F and reflected power P R are filtered through filters 102 , 104 , and 106 . Absolute offset values O 1 and O 2 , and multipliers k 1 and k 2 , are user-selected inputs that determine the sensitivity of the arc detection circuitry. The sum of offset O 1 from slow-filtered reflected power and multiplier k 1 applied to filtered forward power sets the upper reflected power limit of dynamic boundary 120 , while the sum of offset O 2 and multiplier k 2 times filtered forward power, inverted through inverter 108 , sets the lower reflected power limit of the dynamic boundary. Upper and lower limits of dynamic boundary 120 are continually recomputed and dynamically updated in response to changes in P F and P R . Comparators 110 and 112 compare the difference between the fast-filtered value of reflected power P R to upper and lower limits, respectively, of the dynamic boundary. Control logic 114 , which is responsive to the comparisons generated by comparators 110 and 112 , controls disconnection switch 116 of an RF power generator.
In the embodiment of FIG. 2 , a fast-filtered value of reflected power P R that falls outside the upper and lower limits of the dynamic boundary 120 indicates detection of an arcing condition in the process or application. FIG. 3 a illustrates examples of arcing conditions 206 and 208 that cause reflected power P R to exceed dynamic boundary 202 , 204 . Referring again to FIG. 2 , in response to the arc detection signal reported from either of comparators 110 or 112 , control logic 114 interrupts power delivery from the RF power generator by opening disconnection switch 116 . Power delivery is interrupted for a time sufficient to quench the arc, at which time control logic 114 instructs disconnection switch 116 to close and normal power delivery resumes.
Dynamic boundary limits are set so as to maximize arc detection sensitivity while minimizing the occurrence of false positive detections. In an representative RF plasma processing application, for example, requiring RF power delivery in the kilowatt range, reflected power offsets of 50–100 watts and forward power multipliers of 4% provided acceptable arc detection performance. The filtering time constants applied to measurements of power delivery parameters, such as forward and reflected power, are similarly chosen based upon performance tradeoffs. Thus, for example, even though some arcs may take a millisecond to develop, they still develop much faster than the expected natural change in impedance presented to the generator due to the tuning actions of an impedance matching network. The slow filter can therefore be set up to have a time constant of one or two ms and still follow normal changes in plasma characteristics. The time constant of the fast filter is typically chosen based on noise considerations, but is generally at least 10 times longer than that of the slow filter. Thus, even though the time constant of the slow filter may be on the order of 1 ms, arcs can generally be detected in a fraction of the time constant of the fast filter.
FIG. 3 a illustrates the further ability of the invention to detect and respond to arcing conditions during tuning or other non-steady state power delivery conditions. To have arc detection while a match network is still tuning, or in systems that never achieve perfect tuning such as fixed match systems with variable frequency RF generators, embodiments of the invention utilize dynamic limits set about the nominal value of the signal being monitored. When power is initially applied from an RF generator to a plasma load, for example, an impedance mismatch is typically present between the load impedance and the output impedance of the generator. As a result, reflected power is initially high. An impedance matching network operates to tune the system to improve power transfer by reducing reflected power, as illustrated for example by the decreasing reflected power curve 200 of FIG. 3 . Upper 202 and lower 204 limits of a dynamic arc detection boundary are computed continuously and track the instantaneous level of reflected power. As a result, arcing conditions 206 and 208 may be detected and handled during power tuning without waiting for the power delivery to reach a steady state condition. Moreover, arc detection and handling may continue to operate in the event that load conditions change and retuning of the system occurs.
Once arcs are detected, many options are available for handling and extinguishing the arcs. Power delivery may be interrupted, for example, or simply reduced. In one embodiment of the invention, power delivery is interrupted upon initial detection of an arc for a period of 50 to 100 μs, a value that permits a typical processing plasma to return to its normal (i.e. non-arcing) state. In the event the arc is not quenched, a further interruption is triggered for a longer time, e.g. double the length of the first interruption period. This increase in time is continued until either the arc is quenched or a pre-determined number of attempts to quench the arc has failed, in which case the generator shuts down to protect the system. It has been found that RF power delivery may be interrupted in such typical applications for as long as 10 milliseconds with the impedance of the plasma returning quickly (within approximately 20 μs) to the value present before interruption.
In a further aspect of the invention, a sample-and-hold feature is provided in arc detection circuitry in order to address occurrences of persistent or “hard” arcs. Referring to FIG. 2 , in one embodiment of the invention, control logic 114 is equipped to deliver a Hold signal to slow filter 104 upon detection of an arcing event. The Hold signal causes the output of slow filter 104 to be maintained at the value existing immediately prior to occurrence of the arc. As illustrated in FIG. 3 b , the fast-filtered value of reflected power is compared to constant upper and lower arc detection boundaries based upon the nominal value maintained by the slow filter, in order to determine whether conditions of the system have returned to the state prior to occurrence of the arc.
The invention has been described with reference to power delivery systems for plasma processing applications that furnish power in the kilowatt range at radio frequencies, for example 13.56 MHz. The arc detection and handling techniques of the invention may be employed, however, in any apparatus, application or process that furnishes power at any alternating current frequency. Arc detection and handling circuitry of the invention may be implemented within a power generator or match network, in whole or in part, or may alternatively be provided and/or operated separately from other system components. Although the invention provides for arc detection and handling during tuning of a power delivery system, or in other conditions where perfect tuning is never achieved, the invention does not require presence or use of an impedance matching network.
The power delivery parameters upon which dynamic arc detection boundaries are computed are chosen to ensure that arcs are detected reliably with an acceptable false detection rate. Secondary considerations include cost, ease of use, and the ability to classify, count and report arc events. While embodiments of the invention have been described in which dynamic arc detection boundaries are computed based upon measurements of forward and reflected power, other embodiments of the invention compute dynamic boundaries based upon other power delivery parameters such as load impedance; voltage, current and phase; VSWR or reflection coefficient; magnitude level variations in the harmonic output; changes in the RF spectrum harmonics or acoustic interferences; or even variations in electron collision rate or electron density.
In one embodiment of the invention, dynamic arc detection boundaries are computed based upon a DC bias that develops on a process workpiece or target. In addition to being fast and reliable, the approach is advantageous in that the continued presence of the DC bias after the power delivery has been interrupted gives a direct indication that an arc has not yet been extinguished. In cases where a natural DC bias is not developed, a DC power supply is used to inject a DC bias for the purpose of detecting arcs. One potential complication is that the bias detection must be done on the chamber side of the match (that is, the detection would be incorporated in the match), while the arc detection signal must be provided to the RF generator.
Although specific structure and details of operation are illustrated and described herein, it is to be understood that these descriptions are exemplary and that alternative embodiments and equivalents may be readily made by those skilled in the art without departing from the spirit and the scope of this invention. Accordingly, the invention is intended to embrace all such alternatives and equivalents that fall within the spirit and scope of the appended claims. | A radio frequency power delivery system comprises an RF power generator, arc detection circuitry, and control logic responsive to the arc detection circuitry. A dynamic boundary is computed about the measured value of a parameter representative of or related to the power transferred from the power generator to a load. A subsequently measured value of the parameter that exceeds the computed dynamic boundary of the parameter indicates detection of an arc. Upon detection of an arc, power delivery from the generator is interrupted or adjusted, or other action is taken, until the arc is extinguished. By employing dynamic computation of arc detection boundaries, the invention allows for arc handling in RF power deliver systems regardless of whether the system has reached a stable power delivery condition. | 7 |
CROSS REFERENCE OF RELATED APPLICATION
This is a national phase application of an international patent application number PCT/CN2012/081877 with a filing date of Sep. 25, 2012. The contents of these specifications, including any intervening amendments thereto, are incorporated herein by reference.
BACKGROUND OF THE PRESENT INVENTION
Field of Invention
The present invention relates to a method for producing zinc oxide, and more particularly to a method for producing high-purity nanometer zinc oxide.
Description of Related Arts
At present, the smoke and dust from steel plant (including blast furnace grey, converter ash, electric furnace ash), also called smoke and dust storage ash, each producing a ton of steel will produce 35˜90 kg of said smoke and dust, said smoke and dust contains iron of 15˜30%, silicon oxide of 4˜5%, zinc of 5˜22%, combustion fixed carbon (C) of 25˜55%, calcium oxide of 2˜5%, magnesium oxide of 1˜2%, and titanium, vanadium and alkali etc. Under normal conditions, said smoke and dust is generally used as sintering raw materials to produce sinter production, it is recycled in steel plant internal, with enrichment of the cycle, the zinc load entering into furnace is more and more high, seriously affect the normal operation of Blast furnace.
Methods currently limit zinc load in blast furnace contain: one is limiting the amount of recycled smoke and dust; two is mineral processing by the smoke and dust; three is adopting pyrometallurgy and hydrometallurgy. The first method is not an economic and effective method for reducing zinc load of blast furnace, and it brings environmental pollution. The second method is enriching the zinc to the tail mud, but in the mud, but the three products of fine iron, fine carbon and tail mud is disorder, iron, carbon resource are still lost. The third method contains pyrometallurgy and hydrometallurgy, the pyrometallurgy is divided into the treatment of direct sintering method, pelletizing treatment method and direct reduction processing method. But zinc, lead and alkali metals have not been solved. The hydrometallurgy is divided into acid method and alkali method, the process of acid method is maturity, the zinc leaching rate is only about 80% if it is no heating, if rising the temperature, the zinc leaching rate is up to 95%, but the iron is as high as 60%, iron removal is difficult, and a waste of iron, serious corrosion of equipment, is not up to the requirements of environmental protection. But the leaching rate of alkali method is lower. The overall characteristic of existing hydrometallurgy leaching zinc is the zinc leaching rate is low, leached residue is difficult to recycle, unable to meet the requirements of environmental protection, serious equipment corrosion, sensitive to the material requirements, difficult optimization for process , production efficiency is low and the steel output does not match. At present, China's iron and steel enterprises dust containing zinc adding sintering recycling mode has on blast furnace, sintering production and steel plant environment brought great harm, treatment of dust is very urgent.
The most ideal processing method for the steel plant smoke and dust is the selective leaching of zinc, it make the zinc entering into the final leached solution, and recycle zinc valuably.
High-purity zinc oxide usually refers to the zinc oxide product with the mass percent ≧99.7%. The high-purity zinc oxide is an indispensable raw material for the modern high technologies, with wide applications. It is mainly used in glass, feed, ceramics, dyes, paint, paper-making, rubber, pesticides, oil refining, galvanization, special steel, alloy, defence-related science and technology, etc. The glass, paper-making, or rubber, oil refining enterprises have high demands for zinc oxide and very high purity requirement.
The current method for producing high-purity zinc oxide, mainly is the indirect method, said indirect method in general adopts zinc ingots as raw material, through the electrolytic reduction, or high temperature air gasification, oxidation and condensation collection to prepare zinc oxide, adopting different raw materials of zinc ingots, the purity of produced zinc oxide is not the same, this process is mainly the production of zinc oxide of 99.5%-99.7%.
Ammonia method is a commonly used method for producing zinc oxide. Currently, the ammonia method (ammonia—ammonium bicarbonate combined leaching method) for producing zinc oxide generally includes the following steps: leaching of zinc-containing materials using ammonia-ammonium bicarbonate as leaching agent, and after purification, ammonia evaporation crystallization, drying, calcinations of zinc-ammine complexing solution, produce the zinc oxide product. In general, the content of zinc oxide is 95-98%.
Above-mentioned traditional ammonia method for producing zinc oxide has not been used in steel plant smoke and dust, mainly due to the following reasons:
1. Those steel plant smoke and dust have low zinc content (in general, Zn %=5−22), the leached solution has low zinc concentration, high consumption of leaching agent and high cost, so enterprises can not afford; 2. Because of complicated impurities, it only can obtain product of general activity zinc oxide, qualified rate of products is low, product prices are low and economic benefit is difference; 3. Conventional means of leaching, leached rate of zinc ore is low, residual zinc in leached residue is high, resource recycle of Iron, carbon has not formed a complete chain, smoke and dust value not use and reflect.
Nanometer zinc oxide (ZnO) is a new type of high-function fine inorganic product with the particle size between 1 and 100 nm in the 21 st century, exhibiting a variety of special properties such as non-migratory, fluorescence, piezoelectric, absorption and UV scattering ability, etc. With its special optical, electrical, magnetic and sensitivity performance, it can be used to produce gas sensors, phosphors, rheostat, UV shielding materials, image recording materials, piezoelectric materials, varistors, efficient catalysts, magnetic materials, and plastic films, etc.
Currently the methods producing zinc oxide mainly include chemical precipitation method, sol-gel method, microemulsion method and hydrothermal synthesis method, etc. But all raw materials used are zinc calcine or pure zinc salts (such as zinc sulfate, zinc nitrate or zinc acetate) with the zinc content higher than 50%.
Currently, the disclosed technologies of producing nanometer zinc oxide by ammonia leaching method are low-temperature hydrolysis methods, for example:
Chinese Patent Application No. 92103230.7 discloses an improved technology for producing zinc oxide aiming at traditional ammonia complexometry. The purified zinc-ammonia complexing solution is diluted with water to hydrolyze part of zinc-ammonia complexing solution and obtain the basic zinc carbonate (with a ratio of zinc hydroxide and zinc carbonate of 2:1), and then continue to heat until zinc-ammonia complexing solution is decomposed completely. After high-temperature calcinations, 30-100 nn nanometer zinc oxide is obtained.
For the patented technology, the following problems need to be solved:
After hydrolysis, in the thermal decomposition process of undissociated zinc-ammonia complexing solution, the newly generated basic zinc carbonate will continue to grow on the original surface of crystal nucleus, promoting the growing of originally hydrolyzed crystal, which is prone to cause uneven zinc carbonate crystal, making it difficult to control the particle size of the final product.
It adds 4-10 times of water, reducing the efficiency in the preparation process, increasing the energy consumption and the water treatment cost at the back end.
Chinese Patent Application No. 200610130477.7 disclosed an improved technology producing zinc oxide for the traditional ammonia complex method. The zinc-ammonia complexing solution is mixed with 1:2-20 of hot water or hot mother liquor continuously. After heating and heat preservation, it is recycled to be used in hydrolysis of zinc-ammonia complexing solution, to prepare 10-50 nn of nanometer zinc oxide.
For the patented technology, the following problems need to be solved:
After hydrolysis of mother liquor, the ammonia cannot be fully separated, and it cannot achieve the hydrolysis effect, and finally the zinc-ammonia complexing solution is mixed with the zinc-ammonia complexing solution.
For the above two patents, the nanometer crystals are obtained by slightly changing pH value with a large amount of water. In fact, relying solely on the pH value slight change, only a very small part of hydrolysis can be achieved (checked from the ammonium hydroxide solubility curve of zinc oxide). The higher concentration of zinc ammonia liquid, the higher the precipitation efficiency and lower energy consumption; while the lower concentration of zinc ammonia liquid, the lower the precipitation efficiency and high energy consumption. It is technically feasible by artificially increasing the proportion of water to produce nanometer zinc oxide, but it is not feasible in terms of economic efficiency.
In addition, for the current ammonia leaching method for producing zinc oxide, the crystal is basic zinc carbonate, with high decomposition temperature (the initial temperature of zinc hydroxide decomposition is about 125° C., and that of zinc carbonate is about 300° C.). In order to obtain high-purity products, it is necessary to guarantee a high decomposition temperature, generally controlled at above 500° C., to completely decompose the basic zinc carbonate. For example, in the Chinese Patent with Application No. 200610130477.7, the calcinations temperature is as high as 550° C. High-temperature calcinations seriously affect the specific surface area and dispersity of zinc oxide, and thereby affecting its application field.
In summary, for treatment process of the steel plant smoke and dust, how to effectively leach the zinc from materials with low zinc content and get high-purity nanometer zinc oxide and to overcome the disadvantages of traditional pyrometallurgy and hydrometallurgy have become technical problems urgently to be resolved in the industry.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide an effective method for recycling the zinc from steel plant smoke and dust and producing high-purity nanometer zinc oxide.
In order to achieve the above objectives, the present invention is embodied by the follow technical solution: A method for producing a nanometer zinc oxide from steel plant smoke and dust by ammonia decarburization, comprising the following steps:
The steel plant smoke and dust undergoes leaching, purification for impurity removal, crystallization by ammonia evaporation, drying and calcinations, characterized in that:
Take ammonia water-ammonium bicarbonate solution as a leaching agent in said leaching step, in said ammonia water-ammonium bicarbonate solution, the molar concentration c(NH 3 )=5.5-7 mol/L, the molar concentration c(CO 3 2− )=0.95-1.2 mol/L, and adding 0.3-0.5 kg sodium fluorosilicate to per cubic meter of said leaching agent, obtain leached solution after leaching;
Control the concentration of zinc oxide of said leached solution to 50-60 g/L, and then perform heating to decarburize, the procedures are: add 30-60 kg slaked lime to per cubic meter of leached solution and stir, heating to 90-98° C., when c(CO 3 2− )<0.3 mol/L, add ammonium persulfate with the amount of 3-4 kg to per cubic meter of aforementioned solution, add slaked lime powder with the amount of 10 kg/m 3 additionally, continue stir for decarburization and carrying out oxidation reaction, until the concentration of CO 3 2− is C(CO 3 2− )≦0.1 mol/L, perform filter for separation;
Perform refining treatment after purification for impurity removal, the procedure of said refining treatment is: add surfactant to the solution of after purification for impurity removal, the amount of surfactant, such as SDS, is 30-50 g per cubic meter of solution of said after purification for impurity removal, and stir fully.
The procedures for purification for impurity removal, ammonia evaporation crystallization, drying and calcinations adopt the process parameters of common ammonia method for producing zinc oxide.
In the present invention, the existing zinc oxide producing technology is applied to the treatment of steel plant smoke and dust. Meanwhile, under the basis of existing ammonia method, add appropriate amount of sodium fluorosilicate into leaching agent. Add the step of decarburization, after the purification for impurity removal step; add the steps of refining treatment.
In order to obtain high-purity Zinc Oxide, first of all need to ensure zinc in the steel plant smoke and dust can be leached as far as possible, this can increase the recovery of zinc, on the other hand, the content of zinc in the leached solution is more big, the impurity content is smaller, can guarantee the preparation of more higher purity zinc oxide the in same process conditions.
Since the steel plant smoke and dust contains a large amount of iron, which can not be leached out by strong acid, it not only consumes a large amount of acid, but also dissolves out a large amount of iron, it is difficult to purify. The dissolution of zinc ferrite in the acid is also very slow, thus, in the present invention; ammonia method is adopted for leaching. Ultrafine particle in smoke and dust gangue plays an isolating effect for the leaching agent. To resolve this problem, through a lot of experiments, the inventor of the present invention concluded that, appropriate amount of sodium fluorosilicate can get rid of the packing effect of ultrafine particles on the leaching material, to realize the stratification and floating of ultrafine particles, and it makes particles containing zinc is completely immersed in the leaching agent.
By adding the step of decarburization and ammonia reduction, it can on one hand, eliminate the excess of free ammonia, reduce the complexing ability of impurity ion, to remove the impurity ions (Such as high temperature condensed sedimentation for colloid ion such as silicate), enhance the purification quality and reduce the dosage of purified reagents; and on the other hand, it can remove the carbonate ion in the solution, to get the nanometer precursor zinc hydroxide precipitate with a smaller size of crystal nucleus and low decomposition temperature in the subsequent deamination hydrolysis process.
At the same time, through many experiments, the inventor of the present invention concluded that: use slaked lime as decarburization agent, on the one hand it can provide ligand of OH − to replace the CO 3 2− , make CO 3 2− eliminate by the formation of CaCO 3 precipitates, also slightly alkaline environment contributes to the precipitation of metal impurity ion such as iron ion, and create the conditions for the subsequent purification. On the other hand, the lime milk price is low.
Secondly, to get zinc oxide of nanometer scale, it needs to inhibit the growth of crystal particle. The particle size and distribution range of nanometer zinc oxide obtained by the existing ammonia method is unsatisfactory, which mainly contributes to the growing of crystals in the process of treatment, particularly the treatment on the raw material such as steel plant smoke and dust with low content of zinc. To resolve the above problems, through a lot of experiments, the inventor of the present invention concluded that add appropriate amount of surfactant to the solution of being performed Purification for impurity removal, to effectively inhibit the growth of crystal in combination with the high-speed stirring in the process of ammonia precipitation and crystallization.
The chemical reaction equations in the leaching step are as follows:
ZnO+ n NH 3 +H 2 O→[Zn(NH 3 ) n] 2+ +2OH −
ZnFe 2 O 4 +n NH 3 +4H 2 O→[Zn(NH 3 ) n] 2+ +2Fe(OH) 3 ↓+2OH −
ZnFe 2 O 4 +n NH 3 +H 2 O→[Zn(NH 3 ) n] 2+ +Fe 2 O 3 ↓+2OH −
Zn 2 SiO 4 +2 n NH 3 →2[Zn(NH 3 ) n] 2+ +SiO 4 4−
ZnSiO 3 +n NH 3 +2NH 4 HCO 3 →[Zn(NH 3 ) n ]CO 3 +SiO 2 .H 2 O+(NH 4 ) 2 CO 3
Wherein, n= 1˜4;
The chemical reactions in the decarburization step are as follows:
Ca(OH) 2 =Ca 2+ +2OH −
Ca 2+ +CO 3 2− →CaCO 3 ↓
NH 3 .H 2 O+NH 4 HCO 3 →2NH 3 ↑+CO 2 ↑+2H 2 O;
The reactions in the purificaton to remove impurity step:
S 2 O 8 2− +Mn 2+ +2NH 3 .H 2 O+H 2 O→Mn O (OH) 2 ↓+2NH 4 + +2SO 4 2− +2H +
S 2 O 8 2− +2Fe 2+ +6H 2 O→2SO 4 2− +2Fe(OH) 3 ↓+6H +
AsO 4 3− +Fe 3− →FeAsaO 4 ↓
AsO 3 3− +S 2 O 8 2− +H 2 O→2SO 4 2− AsO 4 3− +2H +
2H 3 AsO 3 +8Fe(OH) 3 →(Fe 2 O 3 ) 4 As 2 O 3 .5H 2 O↓+10H 2 O
M 2+ +S 2 →MS↓ wherein, M represents Cu 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Hg 2+ and other ions
As 3+ +S 2− →As 2 S 3 ↓
Y 2+ +Zn→Zn 2+ +Y, wherein, Y represents Cu 2+ , Pb 2+ , Cd 2+ , Ni 2+ and other ions;
Reaction equations in the ammonia evaporation step:
[Zn(NH 3 ) i ] 2+ +2OH − =Zn(OH) 2 ↓+iNH 3 ↑
[Zn(NH 3 ) i ]SO 4 +2NH 3 .H 2 O→Zn(OH) 2 ↓+iNH 3 ↑+(NH 4 ) 2 SO 4 i= 1 ˜ 4 ;
Chemical reaction equation in the drying and calcinations step:
Zn(OH) 2 →ZnO+H 2 O↑.
Preferably, add surfactant additionally with the amount of 0.05 kg˜0.1 kg per cubic meter of said leaching agent, The surfactants can be selected from SDS, etc.
The surfactants can reduce the surface energy, and when combined with sodium fluorosilicate, it can get rid of the coating effect of ultrafine particles, increasing the penetration ability of the leaching agent and enhancing the recovery rate of zinc.
Further, additionally with the amount of 0.5 kg˜1 kg per cubic meter of said leaching agent.
Dicyandiamide, as an ammonia stabilizer, can reduce the volatilization of ammonia in the leaching process, improve the working environment of leaching and reduce the loss of ammonia.
Preferably, wet ball-milling leaching is adopted when leach the smoke and dust.
Further, assure that the leaching time in ball mill is 50˜60 minutes, the material at ball mill outlet all through 140 mesh sieve.
When wet ball-milling leaching mode is adopted, it can damage crystal structure such as zinc ferrite in smoke and dust (achieve the mechanical activation), combines with chemical activation of surfactant and slaked lime, it can achieves a higher leaching speed and leached rate. Through ball milling mechanical activation and the adding of surfactant (sodium fluorosilicate, SDS etc.), higher leached rate is obtained.
Preferably, after decarburization step, add ammonium fluoride to the solution with the amount of 1.5-2.0 times of the theoretical value of Ca 2+ in the solution.
Preferably, detect the zinc content of liquid in the ammonia evaporation equipment at any time in the said crystallization by ammonia evaporation step. When the zinc content is 1-1.5%, add NaOH solution to the ammonia evaporation equipment with the adding amount of 3-5L per cubic meter of said ammonia evaporation solution, and the concentration of said NaOH solution is 30% calculating by mass percent. When the mass percent of zinc is lower than 0.3%, the ammonia evaporation step is finished.
In the late stage of ammonia evaporation, when the zinc concentration in the complexing solution is low, add NaOH to increase the pH value of the solution, which can convert NH 4 + to NH 3 , to achieve the effect of quickly evaporating ammonia and crystallizing, forming nanometer zinc hydroxide crystal nucleus.
Preferably, add sodium stearate solution to the said ammonia evaporation solution with the amount of 3-5L per cubic meter of said ammonia evaporation solution, and the concentration of said sodium stearate solution is 5% calculating by mass percent.
Adding sodium stearate in ammonia evaporation process, it makes the produced nanometer crystalline body closed and package, and makes them no longer continue to grow up.
The second objective of the present invention is to provide a high purity and high performance of high-purity nanometer zinc oxide, the present invention is embodied by the follow technical solution: aid calcinations temperature is 150-280° C.
Due to the technical solution of the invention, after the step of ammonia evaporation for crystallization, it obtains almost all zinc hydroxide, the decomposition temperature of zinc hydroxide is lower than the basic zinc carbonate, calcination with a temperature of 150-280° C., can be obtained zinc oxide product with the purity of more than 99.7% and with large specific surface area, the specific surface area ≧108 m 2 /g, the dispersion of liquidity, with low temperature calcinations, the fluidity and dispersity both better.
The main innovation points of the present invention are as follows: (1) add the decarburization treatment step, to get rid of excess free NH 3 and remove CO 3 2− to achieve the purposes of rapid crystallization when ammonia evaporation; (2) In the step of ammonia evaporation, when the ammonia concentration of zinc-ammonia complexing solution is low, add NaOH to increase the PH value of the solution, to realize the rapid ammonia precipitation; (3) add a surfactant (e.g. SDS) to the zinc-ammonia complexing solution, combined with ammonium sulfate in its own solution, to form crystal nucleus coating film and effectively control the growth of the nanometer zinc oxide crystal nucleus; (4) realize high-speed stirring through the steam power, to control the crystal nucleus of nanometer zinc oxide.
In summary, own to adopt the technical solution, the beneficial effect of the present invention are: the ammonia process is used for treating smoke and dust, and the existing ammonia process is adaptively improved, add sodium fluorosilicate, surfactant and dicyandiamide to the leaching agent when leach, on the one hand, the leaching speed and the leaching rate of zinc in the smoke and dust are improved, add decarburization step and add the resistance change agent to inhibit the growth of crystals in the ammonia evaporation process, and obtain the nanometer zinc oxide precursor with small particle size and uniform particle sizes. On the other hand, the present invention adopts lower calcinations temperature; it can obtain zinc oxide with large specific surface area and purity of up to 99.7%, it is of high economic value; in addition, the treatment method of the present invention is characterized by low energy consumption and high efficiency, the leaching agent can be recycled, and thoroughly solves the problem of zinc load of steel plant furnace smoke and dust, thereby meeting the requirement of the steel plant on purification of the harmful components comprising zinc and alkali metals(leached rate of zinc is up to 90%, removal rate of alkali metals is up to 99%), and achieving good production circulation. And recover valuable steel and carbon source of steel plant, it enriches the steel and carbon source, iron content increased from 15-30% to 18-38%, carbon heat increased from the original about 1000-4500 kcal/kg to 1600-5200 kcal/kg; iron and carbon recycling rate reached more than 98%, both to save energy and create a good economic benefit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is further described in details with the embodiments. One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.
Embodiment 1
Raw material: 1 # steel plant smoke and dust from Kunming, the ingredients: Zn of 9.7%, Fe of 27.14%, Pb of 0.85% Cd of 0.007% C of 28% alkali metal(k, Na) of 2.9%.
The method for producing high-purity nanometer zinc oxide:
(1) Leaching: take 500 g of said 1 # smoke and dust, prepare 1500 ml ammonia water-ammonium bicarbonate solution as leaching agent, of which, the concentration of NH 3 is 4.5 mol/L and the concentration of CO 3 2− is 1.2 mol/L. Add 0.45 g sodium fluorosilicate; perform three-section leaching. The leaching time of each section is 2 hours. After solid-liquid separation, the obtained zinc-ammonium complexing solution contains 43.89 g of zinc (zinc recovery rate is 90.5%);
(2) Decarburization: after leaching step, control zinc oxide of said leached solution to 50 g/L, and then heat for decarburization according to the following procedures: add 60 g of slaked lime to leached solution, heat it 90° C. while stirring.
When the concentration of CO 3 2− =0.3 mol/L, add 3 g ammonium persulfate and 10 g slaked lime to the above liquid, continue to stir for decarburization and oxidation reaction, until c(CO 2 )=0.1 mol/L, and then separate it by filtration;
(3) Purification for impurity removal: add 1.32 g of potassium permanganate to liquid of after separation of step (2) and stir for 0.5 hour meanwhile, add a small amount of polyacrylamide solution (4 mg/L),and then filter, obtain filtrate. Add sodium sulfide to said filtrate with the amount of 1.2 times of the theoretical amount of demanding for precipitation of Cu, Cd, Pb, the temperature is 70° C., stirring time is 2 hour, filter, add KMnO4 to the filtrate with the amount of 2.7 times of the amount of Fe, the temperature is 80° C., stirring time is 1 hour (detection of Fe, Mn until they are qualified), filter, add zinc to the filtrate with the amount of 2.5 times of the theoretical amount for replacing Cu, Cd, Pb, stirring time is 30 min, the temperature is 60° C., filter, obtain filtrate;
(4) after purification for impurity removal, perform refining treatment, the method: Add 0.03 g of surfactant SDS to liquid after purification for impurity removal, obtain refining solution;
(5) Ammonia evaporation and crystallization: Take said refining solution into ammonia evaporation equipment, solution temperature is 105° C. Stop ammonia evaporation when [Zn 2+ ]=1.5 g/L, perform solid-liquid separation for the obtained emulsion, wash filter cake using water according to the ratio of liquid to solid 5:1, washing time is 1 hour, and then filter to obtain filter cake;
(6) Drying and calcinations: dry the filter cake at 105° C., obtain powder, calcine for 60 minutes in a muffle furnace at 280° C., sample and detect, obtain zinc oxide with the purity ZnO%=99.72%, the average particle diameter of nanometer prepared is 14.7 nm (XRD line width method), specific surface area is 109 m 2 /g.
Embodiment 2
Raw material: 2 4 smoke and dust from one steel plant of south, the ingredients: Zn of 6.2%, Fe of 29.6%, Pb of 0.87%, C of 15.24%, Si of 8.7%, alkali metal(k, Na) of 3.47%.
The method for producing high-purity zinc oxide:
(1) Leaching: take 500 g of said 2 4 smoke and dust, prepare 1500 ml ammonia water-ammonium bicarbonate solution as leaching agent, of which, the concentration of NH 3 is 7 mol/L and the concentration of CO 3 2− is 0.95 mol/L. Add 0.75 g sodium fluorosilicate, 0.075 g of surfactant SDS and 0.75 g dicyandiamide to ammonia water-ammonium bicarbonate solution; perform ball-milling while leaching, the leaching time in ball mill is 30 minutes, The ball mill outlet material all through 140 mesh sieve, perform three-section leaching by stirring. The leaching time of each section is 2 hours. After solid-liquid separation, the obtained zinc-ammonium complexing solution contains 28.37 g of zinc (zinc recovery rate is 91.5%);
(2) Decarburization: after the pre-evaporation ammonia, control zinc oxide of said leached solution to 60 g/L, and then heat for decarburization according to the following procedures: add 25 g of slaked lime to leached solution, heat it 98° C. while stirring. When the concentration of CO 3 2− =0.28 mol/L, add 2 g ammonium persulfate and 5 g slaked lime to the above liquid, continue to stir for decarburization and oxidation reaction, until c(CO 2 )=0.09 mol/L, and then separate it by filtration;
(3) Removal of calcium: after finishing the decarburization step, add ammonium fluoride to the solution, the amount of ammonium fluoride is 1.5 times of theoretical value of Ca 2+ in the solution;
(4) Purification for impurity removal: add 0.85 g of potassium permanganate to the solution of after removal of calcium, and stir for 0.5 hour meanwhile, add a small amount of polyacrylamide solution (4 mg/L),and then filter, obtain filtrate. Add sodium sulfide to said filtrate with the amount of 1.2 times of the theoretical amount of demanding for precipitation of Cu, Cd, Pb, the temperature is 70° C., stirring time is 2 hour, filter, add KMnO 4 to the filtrate with the amount of 3.5 times of the amount of Fe, the temperature is 80° C., stirring time is 1 hour (detection of Fe, Mn until they are qualified), filter, add zinc to the filtrate with the amount of 2.5 times of the theoretical amount for replacing Cu, Cd, Pb, stirring time is 30 min, the temperature is 60° C., filter;
(5) after purification for impurity removal, perform refining treatment, the method: Add 0.005 g of surfactant SDS to liquid after purification for impurity removal;
(6) Ammonia evaporation and crystallization: take said refining solution into ammonia evaporation equipment, solution temperature is 108° C. Detect the zinc content in the ammonia evaporation equipment, when the zinc content is 1%, add NaOH solution which mass percent is 30% with the amount of 2.5 mL; stop ammonia evaporation when the mass percent of zinc is lower than 0.3%, obtain emulsion, perform solid-liquid separation for said emulsion, wash filter cake using water according to the ratio of liquid to solid 5:1, washing time is 1 hour, and then filter to obtain filter cake;
(7) Drying and calcinations: dry the filter cake at 105° C., obtain powder, calcine for 60 minutes in a muffle furnace at 200° C., sample and detect, obtain zinc oxide with the purity ZnO%=99.79%, the average particle diameter of nanometer prepared is 23.7 nm (XRD line width method), specific surface area is 115 m 2 /g.
Embodiment 3
Raw material: 3 # smoke and dust from steel plant of southwest, the ingredients: Zn of 15.4%, Fe of 32.53%, Pb of 0.67%, C of 25.28% alkali metal(k, Na) of 2.52%.
The method for producing high-purity zinc oxide:
(1) Leaching: take 1000 g of said 3 # smoke and dust, prepare 3000 ml ammonia water-ammonium bicarbonate solution as leaching agent, of which, the concentration of NH 3 is 5.8 mol/L and the concentration of CO 3 2− is 1.15 mol/L. Add 1.2 g sodium fluorosilicate, 0.3 g of surfactant SDS and 3 g dicyandiamide to ammonia water-ammonium bicarbonate solution; perform ball-milling while leaching, the leaching time in ball mill is 45 minutes, The ball mill outlet material all through 140 mesh sieve, perform three-section leaching by stirring. The leaching time of each section is 2 hours. After solid-liquid separation, the obtained zinc-ammonium complexing solution contains 142.45 g of zinc (zinc recovery rate is 92.5%);
(2) Decarburization: after the pre-evaporation ammonia, control zinc oxide of said leached solution to 56 g/L, and then heat for decarburization according to the following procedures: add 174 g of slaked lime to leached solution, heat it 95° C. while stirring. When the concentration of CO 3 24 =0.27 mol/L, add 10.8 g ammonium persulfate and 30 g slaked lime to the above liquid, continue to stir for decarburization and oxidation reaction, until c(CO 2 )=0.085 mol/L, and then separate it by filtration;
(3) Removal of calcium: after finishing the decarburization step, add ammonium fluoride to the solution, the amount of ammonium fluoride is 2.0 times of theoretical value of Ca 2+ in the solution;
(4) Purification for impurity removal: add 4.3 kg of potassium permanganate and stir for 0.8 hour meanwhile, add a small amount of polyacrylamide solution (4 mg/L),and then filter, obtain filtrate. Add sodium sulfide to said filtrate with the amount of 1.2 times of the theoretical amount of demanding for precipitation of Cu, Cd, Pb, the temperature is 70° C., stirring time is 2 hour, filter, add KMnO 4 to the filtrate with the amount of 3.5 times of the amount of Fe, the temperature is 80° C., stirring time is 1 hour (detection of Fe, Mn until they are qualified), filter, add zinc to the filtrate with the amount of 2.5 times of the theoretical amount for replacing Cu, Cd, Pb, stirring time is 30 min, the temperature is 60° C., filter;
(5) after purification for impurity removal, perform refining treatment, the method: Add 0.15 g of surfactant SDS to liquid after purification for impurity removal;
(6) Ammonia evaporation and crystallization: take said refining solution into ammonia evaporation equipment, solution temperature is 108° C. In the process of ammonia evaporation and crystallization, add 9 ml of sodium stearate solution which concentration is 5%. Detect the zinc content in the ammonia evaporation equipment, when the zinc content is 1.5%, add NaOH solution which mass percent is 30% with the amount of 15 mL; stop ammonia evaporation when the mass percent of zinc is lower than 0.3%, obtain emulsion, perform solid-liquid separation for said emulsion, wash filter cake using water according to the ratio of liquid to solid 5:1, washing time is 1 hour, and then filter to obtain filter cake;
(7) Drying and calcinations: dry the filter cake at 105° C., obtain powder, calcine for 80 minutes in a muffle furnace at 250° C., sample and detect, obtain zinc oxide with the purity ZnO%=99.81%, the average particle diameter of nanometer prepared is 13.2nm (XRD line width method), specific surface area is 118 m 2 /g.
Embodiment 4
Raw material: 4 # smoke and dust from steel plant of Kunming, the ingredients: Zn of 9.7%, Fe of 27.14%, Pb of 0.85%, Cd of 0.0075, C of 28% alkali metal(k, Na) of 2.92%.
The method for producing high-purity zinc oxide:
(1) Leaching: take 1000 g of said 4 # smoke and dust, prepare 3000 ml ammonia water-ammonium bicarbonate solution as leaching agent, of which, the concentration of NH 3 is 6.2 mol/L and the concentration of CO 3 2− is 1.0 mol/L. Add 1.35 g sodium fluorosilicate, 0.6 g of surfactant SDS and 2.4 g dicyandiamide to ammonia water-ammonium bicarbonate solution respectively; perform ball-milling while leaching, the leaching time in ball mill is 80 minutes, The ball mill outlet material all through 140 mesh sieve, perform three-section leaching by stirring. The leaching time of each section is 2 hours. After solid-liquid separation, the obtained zinc-ammonium complexing solution contains 90.01 g of zinc (zinc recovery rate is 92.79%);
(2) Decarburization: after the pre-evaporation ammonia, control zinc oxide of said leached solution to 52 g/L, and then heat for decarburization according to the following procedures: add 112 g of slaked lime to leached solution, heat it 96° C. while stiffing. When the concentration of CO 3 2− =0.29 mol/L, add 8 g ammonium persulfate and 20 g slaked lime to the above liquid, continue to stir for decarburization and oxidation reaction, until c(CO 2 )=0.095 mol/L, and then separate it by filtration;
(3) Removal of calcium: after finishing the decarburization step, add ammonium fluoride to the solution, the amount of ammonium fluoride is 1.8 times of theoretical value of Ca 2+ in the solution;
(4) Purification for impurity removal: add 2.7 kg of potassium permanganate and stir for 0.8 hour meanwhile, add a small amount of polyacrylamide solution (4 mg/L),and then filter, obtain filtrate. Add sodium sulfide to said filtrate with the amount of 1.2 times of the theoretical amount of demanding for precipitation of Cu, Cd, Pb, the temperature is 70° C., stirring time is 2 hour, filter, add KMnO 4 to the filtrate with the amount of 3.5 times of the amount of Fe, the temperature is 80° C., stiffing time is 1 hour (detection of Fe, Mn until they are qualified), filter, add zinc to the filtrate with the amount of 2.5 times of the theoretical amount for replacing Cu, Cd, Pb, stirring time is 30 min, the temperature is 60° C., filter;
(5) after purification for impurity removal, perform refining treatment, the method: Add 0.08 g of surfactant SDS to liquid after purification for impurity removal;
(6) Ammonia evaporation and crystallization: take said refining solution into ammonia evaporation equipment, solution temperature is 108° C. In the process of ammonia evaporation and crystallization, add 10 ml of sodium stearate solution which concentration is 5%. Detect the zinc content in the ammonia evaporation equipment, when the zinc content is 1.5%, add NaOH solution which mass percent is 30% with the amount of 8 mL; stop ammonia evaporation when the mass percent of zinc is lower than 0.3%, obtain emulsion, perform solid-liquid separation for said emulsion, wash filter cake using water according to the ratio of liquid to solid 5:1, washing time is 1 hour, and then filter to obtain filter cake;
(7) Drying and calcinations: dry the filter cake at 105° C., obtain powder, calcine for 70 minutes in a muffle furnace at 200° C., sample and detect, obtain zinc oxide with the purity ZnO%=99.78%, the average particle diameter of nanometer prepared is 13.8 nm (XRD line width method), specific surface area is 115 m 2 /g. | Disclosed is a method for producing a high-purity nanometer zinc oxide from steel plant smoke and dust by ammonia decarburization. The method comprises: leaching with an ammonia water-ammonium carbonate solution as a leaching agent, adding 0.3-0.5 kg of sodium fluorosilicate to per cubic meter of the leaching agent to obtain a leaching solution, then adding 50-60 kg slaked lime to per cubic meter of the leached solution to carry out decarburization with heating, and carrying out purification and impurity removal and then refining treatment. According to the method, the ammonia process is used for treating smoke and dust, and the existing ammonia process is adaptively improved, the leaching speed and the leaching rate of zinc in the smoke and dust are improved, and the zinc oxide with the purity of more than 99.7% can be obtained; the treatment method of the present invention is characterized by low energy consumption and high efficiency, the leaching agent can be recycled, and thoroughly solves the problem of zinc load of steel plant furnace smoke and dust, thereby meeting the requirement of the steel plant on purification of the harmful components comprising zinc and alkali metals and achieving good production circulation. | 8 |
This is a divisional of application Ser. No. 077,672 filed on July 23, 1987.
This invention relates to a spheroidally contoured fabric produced from a yarns which is somewhat difficult to weave.
BACKGROUND OF THE INVENTION
The production of a spheroidally, or more particularly a spherically, contoured fabric of material which is difficult to weave, such as a carbon fiber material, has become desirable in recent times for use in the formation of shims for spherically shaped rocket nozzle parts, for use in the construction of parabolic antennae, and as bases or cores for radar domes made of resin or the like.
In the conventionally finished product, while the warp yarns or threads will be substantially circumferential around the axis of a sphere, in the nature of the latitude lines on a globe, the weft yarns or threads will not run in planes parallel to the axis of the sphere, in the nature of longitude lines on a globe, but rather will be caused to curve away from such positions from the larger diameter edge of the spherical portion to the smaller diameter edge. This problem will be discussed more fully hereinafter. This distortion of the position of the weft yarns or threads makes the fabric unsatisfactory.
Another property of spheroidally contoured fabric is that if it is shaped from fabric in which the weft yarns and warp yarns are uniformly spaced across the fabric, when the fabric is shaped into a spherical shape, the weft yarns will be closer together at the portion of the fabric nearer the pole of the sphere, i.e. the fibers lying along longitude lines of the sphere will converge toward the poles, so that the density of the fabric will increase toward the poles of the spheroid. This can be undesirable.
OBJECTS AND BRIEF SUMMARY OF THE INVENTION
It is the object of the invention to provide a spheroidally contoured fabric in which the density of yarns in the fabric is substantially constant throughout the area of the fabric.
The invention further relates to spheroidal shaped fabrics so produced, in particular to a spheroidally contoured continuous length fabric having warp yarns extending latitudinally and weft yarns extending longitudinally with respect to a pole of a sphere, said warp yarns being positioned closer together the further away from said pole they are positioned, and said weft yarns being substantially equally spaced around said sphere.
It is to be understood that the present invention is for use in producing spheroidal shaped fabrics. However, for simplicity of explanation, the description of the invention is directed only to spherically shaped fabric. It is not intended that the invention be so limited, however.
BRIEF DESCRIPTION OF THE FIGURES
Other and further objects of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, in which:
FIG. 1a is a side elevation view of an annular spherical shim made from spherically contoured fabric produced according to the present invention;
FIG. 1b is a plan view of a developed piece of fabric which can be formed into the shim of FIG. 1a;
FIG. 2 is a plan view of a portion of the apparatus utilized for producing the fabric of the invention; and
FIG. 3 is a schematic plan view of a part of an annular member formed from the spherically contoured fabric made according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the spherically contoured fabric product which it is desired to produce is shown in FIGS. 1a and 1b, and it consists of a spherically contoured piece of fabric preferably made of a difficult to weave yarn, such as low or medium modulus carbon yarn, which is to serve as an annular spherical shim for use in a rocket nozzle. The product, in its finished form as shown in FIG. 1a, is constituted by a section of a sphere, shown in broken lines, which is defined between two parallel planes which extend perpendicularly to the vertical axis of the sphere. As will be appreciated, the shim is designed to lie against the inside of a concave spherical part of the rocket nozzle to shim up a further part which fits into the spherical portion against which the shim rests. Thus, the configuration of the exterior of the shim is part of the surface of a sphere. As can be seen from the right-hand sectional portion, the cross section of the fabric will be circularly curved.
The product is made up from the developed shape as shown in FIG. 1b, and it will be appreciated that the cross section of the developed shape will be the same as that shown in the right-hand part of FIG. 1a, and when the shape lies convex side down on a surface, the shape will be slightly convexly curved upwardly.
It is this developed shape which is produced from the improved rapier-type loom according to the present invention.
As can be seen from the drawings, the outermost warp yarn f of the developed shape will be at a radius r from the center of the shape, and the intermediate warp yarn f i will be at radii r i . The weft yarns will extend substantially radially across the warp yarns, as shown schematically at the poriton F in FIG. 1b.
The apparatus features which allow for the preparation of the fabric of this invention are depicted in FIG. 2. Of particular importance is the presence of a wrap yarn path length extending means generally indicated at 50 in FIG. 2. This means 50 in the preferred embodiment is a series of profiled members in the form of curved bars 51-54. The bars are curved to have a profile similar to that of the profile of the mandrel 40, and the first bar is positioned so that the profile projects in one direction transversely to the path of the fabric, in this embodiment upwardly of the path of the fabric, and the next curved bar 52 having a similar profile projecting in the opposite direction transversely to the path of the fabric, i.e. downwardly from the path of the fabric. The third curved bar projects in the one direction, i.e. upwardly, and the fourth curved bar projects in the other direction, i.e. downwardly. The fabric moving from the shed to the mandrel is diverted back and forth across the normal path of the fabric over each of the bars until it reaches the guidebar 44.
The maximum point of projection of the contour of the bar is at the position corresponding to the center of the longitudinal length of the mandrel 40, and the lowest point on the profile of the bars corresponds to the position of the ends of the mandrel and lies along the path of the fabric.
It will be seen that the warp yarn or yarns which lie along the center of the fabric will be diverted by the first bar 51 out of the normal direct path from the position of the shed to the guide bar 44 a maximum distance above the path, and then diverted by the second bar 52 out of the normal direct path a distance below the normal path of the fabric. These central warp yarns are then directed above and below the normal path again.
The warp yarns at the opposite edges of the fabric, on the other hand, will simply be guided along the ends of the bars in the normal path of the fabric.
the profiles of the bars and the number of bars is determined so that the combination of the normal shorter path length for the mid-fabric warp yarns and their increased velocity will be completely compensated for, so that the portions of the weft yarns carried by these warp yarns will reach the mandrel 40 at the same time as the end portions of the weft yarns held by the warp yarns at the side edges of the fabric. As shown in FIG. 2, this will mean that by the time the weft yarns have reached the guide bar 44, they will not only not have the ends lagging the center, but in fact the ends will have moved forward of the center and the curvature of the weft yarns will correspond to the profile of the mandrel 40. Thus, when the fabric is guided over the guide 44 onto the mandrel 40, the weft yarns will lie along lines corresponding to longitudinal lines on the spherical shape of the mandrel portions 41 and 42. As a result, the finished fabric when it is taken off will have a spherical shape, yet the warp yarns and the weft yarns will be in the proper longitudinal and latitudinal relationship in relation to the spherical shape of the fabric.
In view of the configuration of mandrel portions 41 and 42, in essence two linked spheroidal portions are provided.
This approach provides the spheroidally contoured fabric, specifically a spherically contoured fabric, with a construction which has the desirable property that the yarn density is more uniform throughout the fabric.
As pointed out above, if the warp yarn supplied to the loom for making the spherically shaped fabric are uniformly spaced across the width of the fabric, these warp yarns in the finished fabric will be in the positions corresponding to latitudinal lines on a sphere, and will be at equal distances from each other across the surface of the sphere. The weft yarns, on the other hand, will correspond to longitudinal lines on the sphere and will converge toward the poles of the sphere. As a result, the density of the fabric, i.e. the number of yarns per unit area, will increase toward the poles.
To change this property, the present invention provides for causing the warp yarns toward the center of the width of the fabric, i.e. toward the larger diameter part of the finished spherically contoured fabric, to be closer together than at the edges of the fabric. As a result, as shown in FIG. 3, the yarns 70 lying along the latitudinal lines will be closer together toward the larger diameter part, and become progressively further apart the closer to the small diameter part they lie. By properly spacing the warp yarns in the loom, the number of fibers 70 and 71 per unit area of the fabric can be made substantially uniform.
Although the invention has been described by way of example with respect to only a single embodiment, it will be understood that various changes and modifications may be made without departing from the scope and spirit of the invention, and it is intended that such changes and modifications be included within the scope of the appended claims. | A contoured continuous length fabric having warp yarns extending latitudinally thereof which are positioned closer together as they approach the outer contoured surface of the fabric and weft yarns extending longitudinally and being substantially equally spaced along the length thereof relative to each other. | 3 |
OBJECT OF THE INVENTION
[0001] The present invention relates to a forming method and system for obtaining an essentially cylindrical and essentially hollow final metal part, with a thickness of the bottom that is essentially greater than the thickness of its walls, from a preferably disc-shaped sheet metal. The invention is specifically comprised in the metal working sector, and more specifically in the manufacture of ammunition cartridge cases.
BACKGROUND OF THE INVENTION
[0002] Deep drawing is a technique that allows obtaining from planar and essentially thin sheet metal with a specific thickness an object the shape of which is predetermined and is essentially cylindrical and hollow. In this process, the sheet is deep drawn in a deep drawing die by the mechanical action of a punch.
[0003] Multistage deep drawing is characterized by being a process comprising several consecutive deep drawing and redrawing operations. Deep drawing is the action of mechanically deforming planar sheet metal against the deep drawing die with the aid of the punch. Redrawing comprises repeated deep drawing stages in which the part is gradually deformed iteratively until reaching the desired final shape.
[0004] Sometimes an ironing process is applied after deep drawing stages. Ironing is characterized by being a process which allows reducing the thickness of the wall of the previously deep drawn part and consists of passing the previously deep drawn part through an ironing die.
[0005] In the metal working sector, the manufacture of ammunition cartridge cases is done by first performing the deep drawing operations to obtain the inner shape of the part and to subsequently reduce the thickness of the walls and increase the length of the part by means of successive ironing operations. The deep drawing, redrawing and ironing stages are fundamentally defined by means of design rules based on the empirical tests without taking into account the plastic evolution of the material and without considerations concerning the combination of stages or optimization of the process.
[0006] The present invention provides a different process that allows manufacturing final parts with different design parameters and an optimized process that substantially improves the results obtained up until now.
[0007] This invention is based on the contributions made in the articles entitled “ The development of competencies in manufacturing engineering by means of a deep - drawing tool”, “Prediction of the limiting drawing ratio and the maximum drawing load in cup - drawing”, “On multistage deep drawing of axisymmetric components ” and “Energia de estirado en deformación homogénea”. The definition of new methods based on aided design capable of improving some results has been the object of patents, such as U.S. Pat. No. 7,623,939 B2 “Method of design a tool for deep drawing and tool for deep drawing of sheet metal”, based on parameterized geometry and on meeting quality criteria.
DESCRIPTION OF THE INVENTION
[0008] The present invention provides a process that is different from the process of the state of the art that allows manufacturing final parts with different design parameters, leading to a lower process cost and lower power consumption by basing the dependence of the latter on the manufacturing forces, work and time. The invention describes a sheet metal forming process for obtaining an essentially cylindrical and essentially hollow final metal part according to claim 1 and a sheet metal forming system according to claim 6 .
[0009] In the context of the present invention the term “forming” refers to the forming of metal materials, i.e., the technique of giving shape to a sheet metal or metal disc to obtain a part having the desired shape and volume. “Molding” or “forming” shall be referred to indistinctly hereinafter.
[0010] A first inventive aspect relates to a sheet metal forming process for obtaining an essentially cylindrical and essentially hollow final metal part in a system comprising at least the following elements:
a plurality of deep drawing dies to perform deep drawing and redrawing operations from sheet metal simultaneously with ironing operations in a combined manner, a plurality of ironing dies to perform ironing operations in each stage simultaneously with the iterated deep drawing operations, a plurality of blank-holder elements for holding or securing the part that is being deep drawn which allow eliminating the occurrence of creases or wrinkles in the part that is being formed, centering and guiding elements for centering and guiding parts through the dies, a plurality of punches, and at least some processing means suitable for giving all the preceding elements full capability to carry out the process (deep drawing and ironing force, working speed, etc.).
[0017] The process is performed in a system comprising the described elements comprised in machinery used for the process, each one performing a function in the simultaneous deep drawing and ironing process of the invention. As in the state of the art, one deep drawing die is used for each deep drawing step such that it contains the shape that will be given to the metal part to be obtained in each step. The present invention represents each step with a sign i and n steps are completed.
[0018] The punches are adapted to the inner dimensions of the inner diameters of the intermediate parts in the intermediate stages to be obtained in the combined process. Each punch in each stage i mechanically operates on the sheet or disc (first stage) or metal part (subsequent stages), first passing the part through the deep drawing die and then through the ironing die, and so on and so forth for each stage.
[0019] The blank-holder elements for holding or securing the part that is being deep drawn (securing means for securing the part) of each stage i are used to prevent the occurrence of creases or wrinkles during the combined, simultaneous deep drawing/ironing operation.
[0020] To assure that the machinery acts in a controlled manner in each stage i, processing means are used to program machinery operation with parameters such as the working pressure of the machine and the travelling speeds of the punches during the approach, operation and recovery.
[0021] The process is characterized in that it comprises i stages (i=1 . . . n) (i=1 . . . n) in which the following steps are performed:
a) if i=1, providing the preferably disc-shaped sheet metal, b) if i≠1 providing an intermediate metal part from the preceding stage, c) providing working parameters to the processing means of the elements that are involved, such as the working pressure and the approach, operating and recovery speeds of the punch, d) performing a simultaneous deep drawing and ironing operations using the working parameters, making the deep drawing die, punch, ironing die and blank-holder elements work simultaneously, obtaining an essentially cylindrical and essentially hollow intermediate metal part as a result, e) if i≠n, repeating from step b) providing the essentially cylindrical and essentially hollow metal part obtained in d) as the metal part,
such that when i=n the essentially cylindrical and essentially hollow final metal part is obtained as a result.
[0027] If the process is performed in a mass production line, each of the previously described elements is situated in the mass production line, there being a deep drawing die, a punch, securing means, a ironing die in each step of the mass production line, and operations are carried out consecutively by completing actions a) to e) in each step of the mass production line.
[0028] The sheet metal to be formed, which is disc-shaped in one embodiment, is provided for the first step. The machinery operating parameters are programmed by means of the processing means in the first step of the mass production line.
[0029] A deep drawing and ironing operation is performed simultaneously, unlike the processes of the state of the art where the deep drawing and ironing actions are performed consecutively, one after the other.
[0030] The invention proposes the simultaneous combination of deep drawing and ironing processes such that they are performed simultaneously, i.e., the deep drawing and the ironing are no longer consecutive stages such as in the state of the art but rather are performed in a single action such that in each step, the deep drawing die, the punch, the blank-holder and the ironing die operate together, making all these elements work at the same time.
[0031] This invention therefore allows obtaining parts with less overall work performed and lower power consumption during the process as more similar forces are achieved in each stage to obtain the final part, as well as in the intermediate stages, more uniform deep drawing coefficients, reduction coefficients for the thickness of the wall and length of the part, producing fewer deformations, all with a lower manufacturing cost and overall process time, the process therefore being of maximum industrial interest.
[0032] At the end of the simultaneous deep drawing and ironing operation, an essentially cylindrical and essentially hollow intermediate metal part is provided in the first stage as a result to provide it in the subsequent stage of the mass production line. Therefore, the same is done in the second stage of the process as in the preceding stage, complying with the working parameters programmed for the second stage. The intermediate metal parts are essentially cylindrical and essentially hollow, i.e., tube-shaped with a variable and hollow section in the sense that the punch has been inserted in said parts such that a cavity remains inside with variable thickness, which thickness is considerably different for the bottom of the part and the walls, a characteristic that characterizes ammunition cartridge cases.
[0033] The desired final metal part is provided when the last stage n of the process is reached.
[0034] The number of combined deep drawing and ironing stages depends on the ratio existing between the dimensions of the sheet metal to be formed and on the dimensions of the final metal part to be obtained, on how easy the deep drawing of the material is and on the thickness of the sheet. The greater the depth to be given to the final metal part to be obtained, the more stages will be necessary for the deep drawing and ironing, and therefore more tools and operations will be needed. It is therefore necessary to envisage the way to always perform operations with the lowest number of stages. The number of stages n to be performed is conventionally determined with data provided with the experience of the person skilled in the art, but it can be the result of simulations and optimizations to achieve less overall work performed, lower power consumption during the process, and achieving more similar forces in each stage.
[0035] Ironing stages are mainly used in the state of the art to reduce the walls of parts such as tubes for automotive uses, pipes, wires, etc. Simultaneously combining deep drawing and ironing stages leads to obtaining parts the geometry of which is such that the thickness of the bottom obtained in the final part is substantially greater than the thickness of the walls, because the thickness of the walls has been gradually reduced in each step of the simultaneous deep drawing and ironing action. Therefore, it is an interesting technique in industry for parts requiring this geometry, and particularly in the manufacture of ammunition cartridge cases.
[0036] A second inventive aspect relates to a sheet metal forming system for obtaining an essentially cylindrical final metal part comprising:
a plurality of deep drawing dies to perform deep drawing operations from sheet metal simultaneously with ironing operations in a combined manner, a plurality of ironing dies to perform ironing operations in each stage simultaneously with the iterated deep drawing operations, a plurality of blank-holder elements for holding or securing the part that is being deep drawn that allow eliminating the occurrence of creases in the part that is being deep drawn, centering and guiding elements for centering and guiding parts through the dies, a plurality of punches, and at least some processing means suitable for giving all the preceding elements full capability to carry out the process (deep drawing and ironing force, working speed, etc.),
characterized in that it is suitable for implementing a forming process according to the first inventive aspect.
[0043] If the process is performed in a mass production line, the system is the set of deep drawing dies, punches, ironing dies and securing means as well as the processing means suitable for programming all the described machinery.
[0044] A third inventive aspect relates to a computer program, characterized in that it comprises program code means to perform the simulation stages of a forming process.
[0045] A fourth inventive aspect relates to a computer-readable medium, characterized in that it contains a computer program comprising program code means to perform the simulation stages of a forming process.
[0046] A fifth inventive aspect relates to an electronic signal containing information, characterized in that it allows reconstructing a computer program according to the third inventive aspect.
[0047] All the technical features described in this specification (including the claims, description and drawings) can be combined in any way except for those features that are mutually exclusive.
DESCRIPTION OF THE DRAWINGS
[0048] These and other features and advantages of the invention will be better understood from the following detailed description of a preferred embodiment, given only by way of illustrative and non-limiting example in reference to the attached drawings.
[0049] FIG. 1 shows a depiction of the geometry of an artillery cartridge case, where the thickness of the bottom is shown to be substantially greater than that of the walls.
[0050] FIG. 2 depicts a mass production line for producing metal parts by a metal part forming process such as the process of the invention. The different elements used in each step of the mass production line are observed in the drawing.
[0051] FIG. 3 a depicts a step i of the sheet metal forming process where the operated elements and the intermediate metal part with a specific shape are observed.
[0052] FIG. 3 b depicts an intermediate step j of the forming process j>ij>i for forming the part of FIG. 3 a such that it is more formed.
[0053] FIG. 4 a shows the evolution of the outer diameter of the part that is obtained in each step in millimeters in an experimental example.
[0054] FIG. 4B shows the evolution of the thickness of the wall of the part that is obtained in each step in millimeters in an experimental example.
[0055] FIG. 4C shows the evolution of the total length of the part that is obtained in each step in millimeters in an experimental example.
[0056] FIG. 5 depicts the evolution of the drawing ratio in each step of the process.
[0057] FIG. 6 depicts a flow of actions performed in an optimized combined simulation process.
DETAILED DESCRIPTION OF THE INVENTION
[0058] The present invention relates to a sheet metal ( 1 ) forming process for obtaining an essentially cylindrical and essentially hollow final metal part ( 2 ). Specifically, the forming process is of interest in the manufacture of ammunition cartridge cases the particular geometry of which depicted in FIG. 1 , with the thickness of the bottom greater than the thickness of the walls, allows combining deep drawing and ironing stages simultaneously for the manufacture. The invention also relates to the system where the forming process is implemented.
Sheet Metal Forming System
[0059] The system, one of the embodiments of which is depicted in FIG. 2 , comprises at least the following elements:
a plurality of deep drawing dies ( 5 1 - 5 n ) to perform deep drawing operations from sheet metal ( 1 ) simultaneously with ironing operations, a plurality of punches ( 6 1 - 6 n ), a plurality of blank-holder elements ( 8 1 - 8 n ) for holding or securing the part that is being deep drawn, centering and guiding elements for centering and guiding parts through the dies, a plurality of ironing dies ( 7 1 - 7 n ) to perform ironing operations in each stage simultaneously with deep drawing operations, and at least some processing means ( 4 ) suitable for giving all the preceding elements full capability to carry out the process (deep drawing and drawing force, working speed, etc.).
Forming Process by Means of Simultaneous Deep Drawing and Ironing Operations
[0066] The process is characterized in that it comprises i stages (i=1 . . . n) in which the following successive steps are performed:
a) if i=1, providing the sheet metal ( 1 ), b) if i≠1, providing an intermediate metal part ( 3 i-1 ), c) providing working parameters to the processing means ( 4 ) of the elements that are involved, such as working pressure and approach, operating and recovery speeds of the punch ( 6 i ), d) performing a simultaneous deep drawing and ironing operation using the working parameters, making the deep drawing die ( 5 i ), punch ( 6 i ), ironing die ( 7 i ) and blank-holder element ( 8 i ) work simultaneously, obtaining an essentially cylindrical and essentially hollow intermediate metal part ( 3 i ) as a result, e) if i=n, repeating from step b) providing the essentially cylindrical and essentially hollow metal part ( 3 i ) obtained in d) as the metal part,
such that when i=n, the essentially cylindrical and essentially hollow final metal part ( 2 ) is obtained as a result.
[0072] FIG. 2 depicts a mass production line with the tool arranged in the mass production line so that one station is used in each step i to obtain an intermediate metal part ( 3 ). In the first step the sheet metal ( 1 ) is formed, and the final metal part ( 2 ) is obtained from the last step n. The processing means ( 4 ) are depicted in the figure as means suitable for accepting input data through a numerical keypad and display means, such as a screen for example.
[0073] In one embodiment of the invention, a drawing ratio of the first stage, DR 1 , is applied DR 1 , which allows the thickness of the bottom to remain unchanged, given that in one embodiment of the invention, the application is the manufacture of ammunition cartridge cases and it is fundamental for this thickness of the bottom to remain constant throughout the multistage process.
[0000]
DR
i
=
diameter
resulting
part
stage
i
-
1
diameter
part
stage
i
[0074] Usually for drawing ratios greater than 1.5, the material is drawn in the bottom region of the part, a phenomenon that should not occur in the embodiment of the invention.
Simulation of a Combined Process of Simultaneous Deep Drawing and Ironing Operations
[0075] In one embodiment of the invention, the forming parameters, working parameters and number of stages n are predetermined by means of a simulation process that allows obtaining a first combined solution. The simulation process can be performed by processing means, for example a computer, or a microprocessor suitable for implementing the stages of the optimized simulation.
[0076] The combined simulation comprises two different parts: a simulation of deep drawing and ironing operations without simultaneously combining them and a combination of the stages for combining deep drawing and ironing operations simultaneously.
[0077] Simulation without Simultaneously Combining Deep Drawing and Ironing Operations
[0078] The simulation starts with the stages corresponding to the deep drawing operations:
providing design data about a simulated metal part ( 10 ) to be obtained, preferably the type of material to be used and the dimensions of the simulated metal part ( 10 ) to be obtained, such as the length of the final part, the thickness of the wall of the final part and the diameter of the final part, calculating the dimensions of preferably disc-shaped simulated sheet metal ( 9 ) necessary for obtaining a simulated metal part ( 10 ) the characteristics of which coincide with those provided in the preceding step, calculating the initial dimension of at least the following elements used in a first simulation,
a simulated punch, simulated blank-holder, a simulated deep drawing die and a simulated ironing die,
performing in each step w, (w=1 . . . q)w, (w=1 . . . q):
a) if w=1, performing a simulation of the deep drawing of the simulated sheet metal ( 9 ) by means of a deep drawing simulation algorithm using the design parameters, obtaining an intermediate metal part ( 11 1 ) as a result, b) if w≠1, performing a simulation of the deep drawing of the intermediate metal part ( 11 w-1 ) by means of a deep drawing simulation algorithm using the design parameters, obtaining another simulated intermediate metal part ( 11 w ) as a result, c) calculating and storing data about the simulation, preferably data about the resulting simulated intermediate metal part ( 11 w ), such as the diameter, length and thickness of the wall, and the parameters of the participating elements, such as the dimensions of the simulated elements: a simulated punch, simulated blank-holder and a simulated deep drawing die, the approach, operating and recovery speeds of the punch in step w, d) if the data about the resulting simulated intermediate metal part ( 11 w ) does not coincide with the data about the simulated metal part ( 10 ) to be obtained, continuing in b) until reaching a step w=q w=for which a resulting simulated intermediate metal part ( 11 w ) is obtained,
such that if the inner diameter of the simulated intermediate part ( 11 w ) coincides with or is less than the inner diameter of the part to be obtained, this intermediate phase is adopted as the last phase of the multistage deep drawing process, and all the stored data about the intermediate metal parts ( 11 1 - 11 n ) in each simulation step w,w=1 . . . q w,w=1 . . . q, as well as the parameters of the participating elements, such as the dimensions of the simulated elements: a simulated punch, simulated blankholder, a simulated deep drawing die and a simulated ironing die, the speed of the punch and the deep drawing die, the speed of the ironing die in each step w and the number q are provided as a result of the last iteration, n.
[0091] The deep drawing is simulated in a first instance. Providing the design data in the first stage is done by the user through data input means, for example a computer keyboard. The following data is used in a particular example: inner diameter of the simulated metal part ( 10 ) to be obtained, length, thickness of the bottom, thickness of the wall and type of material.
[0092] In the second stage, the calculation of the dimensions of the simulated sheet metal ( 9 ) necessary for obtaining a simulated metal part ( 10 ) is done by the processing means. This calculation is based on parameters such as the data entered by the user and characteristics of the selected material, such as physicochemical characteristics for example, specifically: density, tensile strength limit, yield strength limit, rigid-plastic behavior constant, strain hardening exponent and normal anisotropy value of the material. The dimensions of the starting sheet ( 9 ), which are the source for carrying out the deep drawing steps until achieving the final dimensions of the simulated metal part ( 10 ) to be obtained, are obtained considering the condition of incompressibility in the plastic deformation process and the condition of constant thickness of the bottom throughout the entire manufacturing process.
[0093] In the same manner, the initial dimension of elements used in a first simulation: the simulated punch, the simulated securing means, the simulated deep drawing die and the simulated ironing die, i.e., the dimension of the tool, is calculated by the processing means. The design of this punch is calculated as a function of the limiting drawing ratio and of the final dimensions of the simulated metal part ( 10 ) to be obtained. The initial solution is determined from the consideration of two limiting deep drawing conditions. The first limiting deep drawing condition is based on the fact that the maximum force exerted by the punch on the part during the deep drawing process must be less than the breaking load of the material. The second limiting deep drawing condition focuses on the limiting drawing ratio, and considering the condition of constant volume throughout the plastic deformation process, the limiting value of the drawing ratio is determined for the established conditions by the input data, the normal anisotropy coefficient of the material considered, the efficiency factor of the deep drawing process and the strain hardening coefficient.
[0094] A value of the diameter of the die, the thickness and the limiting drawing ratio are determined with the data about the dimensions obtained for the simulated punch. It is therefore possible to obtain a first diameter of the punch as a function of the diameter of the die and of the thickness of the disc of the part.
[0095] Once the dimensions of the simulated tool are calculated for the initial stage, w=1, an iterative simulation process of deep drawing actions starts, the number of stages of which will be such that, given the described characteristics of the selected material used, such as physicochemical characteristics for example, specifically: density, tensile strength limit, yield strength limit, rigid-plastic behavior constant, strain hardening exponent and normal anisotropy value of the material, a simulated final metal part ( 10 ) the inner diameter of which is the inner diameter of the simulated final metal part ( 10 ) to be obtained is achieved.
[0096] The simulation model provides the dimensions of the simulated tool for the initial stage, w=1, as input values of the simulation steps in which w≠1. The walls of the part remain considerably constant throughout the successive deep drawing steps, maintaining the original thickness of the bottom of same, which coincides with the starting disc. The purpose of the successive deep drawing steps is to obtain specific dimensions of the part such that it is prepared for the subsequent drawing process, i.e., to perform deep drawing steps until the inner diameter of the part (diameter of the punch) coincides with the inner diameter of the simulated final metal part ( 10 ) to be obtained. The initial solution for the deep drawing step w≠1 is established based on the consideration of three limiting deep drawing conditions. The variable considered for the calculation is, such as for w=1, the diameter of the die. The model selects the largest diameter from among the three diameters obtained in the three deep drawing conditions. Once the diameter is known, the model determines the remaining dimensions necessary for defining the part corresponding to this step. If the required inner dimension of the part is not achieved in w=1, the model performs as many successive deep drawing steps, w, as needed, i.e., an iterative process, until obtaining that step w=q in which the inner diameter coincides with or is less than the inner diameter of the final part to be obtained.
[0097] The first limiting redrawing condition is established with the requirement that the maximum deep drawing force exerted by the punch on the simulated intermediate part ( 11 w ) during the deep drawing process must be less than the breaking load of the material. By means of an iterative process and considering the tensile strength limit of the material, the friction coefficient of the material and the angle of entry into the die, the desired diameter of the part is obtained from the diameter of the punch of the preceding step w−1 as a function of the thickness and of the diameter of the punch in this step w, and the process is performed iteratively, as many times needed, until obtaining the diameter of the punch corresponding to the last step of the deep drawing process w=q.
[0098] With respect to the second limiting deep drawing condition, said condition focuses on the rigid-plastic behavior of the material, therefore the outer diameter of the part of a generic stage 14 ; of the deep drawing process can be determined with respect to the diameter of the preceding stage w−1 and the final deformation.
[0099] Concerning the third limiting deep drawing condition, which focuses on the restriction of the limiting drawing ratio, the limiting drawing ratio is applied in the deep drawing operations, considering the effects of normal anisotropy of the material, the friction coefficient, the strain hardening coefficient and the radius of entry into the die. The limiting drawing ratio is used in this model as a variable to determine the necessary number of deep drawing steps w and the dimensions of the corresponding tools. It is assumed that the material is rigid-plastic. Given the consideration that the material is rotationally symmetrical, the properties of same are based on the existence of normal anisotropy and planar isotropy. It is considered that the stress created in the region of the radius of the redrawing die, which causes plastic instability in the wall of the cup, is equal to the radial deep drawing stress in the region of the flange, due to the continuity of the stress throughout the entire part.
[0100] It is therefore possible to determine the values of the limiting drawing ratio for each phase of the redrawing process starting from a given die radius and the reduction thereof in each deep drawing step w. Once the limiting drawing ratio corresponding to each deep drawing step w is known, the model determines the diameter of each step, giving a value to the diameter of the punch of a step w as a function of the ratio between the diameter of the preceding step w−1 and the limiting deep drawing limit.
[0101] The result of this iterative process is the provision of all the stored data about the intermediate metal parts ( 11 1 - 11 q ) in each simulation step w,w=1 . . . q w,w=1 . . . q, as well as the parameters of the participating elements, such as the dimensions of the simulated elements: a simulated punch, simulated securing means, a simulated deep drawing die, the speed of the punch in each step w and the number q.
[0102] The simulation continues with the stages corresponding to the ironing operations as follows:
performing in each step j, (j=1 . . . m)j, (j=1 . . . m):
e) if j=1, performing a simulation of the ironing of the simulated previously deep drawn metal part ( 9 ) by means of a ironing simulation algorithm using the design parameters, obtaining a drawn intermediate metal part ( 11 1 ) as a result, f) if j≠1, performing a simulation of the ironing of the intermediate metal part ( 11 j-1 ) by means of a ironing simulation algorithm using the design parameters, obtaining another simulated intermediate metal part ( 11 j ) as a result, g) calculating and storing data about the simulation, preferably data about the resulting simulated intermediate metal part ( 11 j ), such as the diameter, length and thickness of the wall, and the parameters of the participating elements, such as the dimensions of the simulated elements: a simulated punch, simulated blank-holder, a simulated ironing die, the approach, operating and recovery speeds of the punch in step j, h) if the data about the resulting simulated intermediate metal part ( 11 j ) does not coincide with the data about the simulated metal part ( 10 ) to be obtained, continuing in f) until reaching a step j=m for which a resulting simulated intermediate metal part ( 11 j ) is obtained,
such that if the thickness of the wall of the simulated intermediate part is equal to or less than the thickness of the final part to be obtained, this intermediate phase is adopted as the final phase, the thickness of the final part being the thickness corresponding to that of the last stage, and all the stored data about the intermediate metal parts ( 11 1 - 11 m ) in each simulation step j,j=1 . . . m, as well as the parameters of the participating elements, such as the dimensions of the simulated elements: a simulated punch, simulated blankholder, a simulated deep drawing die and a simulated ironing die, the speed of the punch and the deep drawing die, the speed of the ironing die in each step j and the number m are provided as a result of the last iteration, m.
[0108] Ironing operations are simulated in this second instance, i.e., the thickness of the wall is progressively reduced until achieving the thickness of the final part. New conditions for obtaining diameters are established. The number of steps needed will depend on the dimensions of the simulated final metal part ( 10 ) to be obtained. The considered model is based on complying with three limiting ironing conditions in each of the ironing steps, and starting from the data about the deep drawing process. The diameter of the intermediate metal parts ( 11 1 - 11 m ) is determined for each limiting ironing condition, and the largest diameter of the three is chosen because the model requires complying with the three limiting conditions. If the chosen diameter is greater than the final diameter of the part produced by the deep drawing process, the model stores the data obtained as data corresponding to an intermediate step j and again repeats the process. The process is recurrent until the final thickness of the part to be obtained is achieved.
[0109] The first limiting ironing condition is determined by the fact that the mean ironing stress must be less than the breaking stress of the material. This first limiting drawing condition provides the diameter as a function of: the tensile strength limit of the material, an ironing coefficient depending on the material, the diameter of the part in the preceding stage j−1 and the ironing force in said stage j−1.
[0110] Concerning the second limiting ironing condition, it is expressed as the stress exerted in the material ironing process being less than the yield limit. Starting from annealed material and using an efficiency factor, the expression corresponding to the second limiting ironing condition is determined, and the diameter is determined as a function of the diameter of the preceding stage j−1 and the increase in deformation.
[0111] The third limiting ironing condition, relating to the limiting thickness reduction coefficient, must be complied with. This coefficient starts from empirical considerations. A coefficient is considered in the simulation method for each deep drawing step w that fundamentally depends on the drawing step j and on the type of material used.
[0112] Combination of the Simulation for Simultaneously Combining Deep Drawing and Ironing Operations
[0113] After the simulation of the deep drawing and ironing operations separately, a combination of the number of deep drawing and ironing stages is performed such that the combined number n depending on q and m is obtained.
[0114] Therefore, the forming parameters, working parameters and number of stages, after having been predetermined by means of the non-combined simulation process, are combined by means of a process that combines the number of deep drawing and ironing stages such that the combined number n depending on q and m is obtained, whereby it is possible to perform deep drawing and ironing simultaneously in successive iterative steps instead of implementing them consecutively.
[0115] Five deep drawing steps and 2 ironing steps have been determined in one embodiment. By applying the combination, both processes are combined to perform only 5 steps instead of 7 steps (5+2).
Optimized Simulation by Simultaneously Combining Deep Drawing and Ironing Operations
[0116] In one embodiment, the process optimizing the number of deep drawing and ironing stages such that the optimal number n is obtained is described below. The simulation combines deep drawing operations with ironing operations, such that the total number of stages is reduced, and the manufacturing time, process cost, overall work performed and energy consumption are also reduced. The optimal number n depending on q and m is thus obtained and comprises the steps of:
[0117] Combined Simulation
providing the data about the intermediate metal parts ( 11 w , 11 j ) provided by the simulation without simultaneously combining deep drawing and ironing operations in each simulation step, as well as the parameters of the participating elements, such as the dimensions of the simulated elements: a simulated punch, simulated blank-holder, a simulated deep drawing die and a simulated ironing die, the approach speed of the punch, the operating speed of the punch and the recovery speed of the punch in each step, and the numbers q,m, if q<m (deep drawing steps<ironing steps), n=m is used and the combined process follows the following steps: i. the diameter of step w=1 is used as the diameter of the first step i=1, j. the thicknesses calculated in the non-combined solution of ironing stages j=1 to j=n−1 are used as the thicknesses of the wall of stages i=1 to i=n−1, k. the final diameter to be obtained is used as the final diameter of the stage i=n, l. the thickness of the final part to be obtained is used as the thickness of the wall of the stage i=n, m. the thickness of the final part to be obtained is used as the thickness of the bottom of the n combined stages, and it remains unchanged throughout the entire combined process, n. the mouth thickness reduction ratios,
[0000]
K
i
=
thickness
stage
i
-
1
thickness
stage
i
K
i
=
espesoretapai
-
1
espesoretapai
,
obtained in ironing stages j=1 to j=n are used,
o. the drawing ratio obtained in the first simulation stage of the deep drawing operations, w=1, is used as the drawing ratio of the first stage DR i ,
p. the drawing ratios DR i and the diameters of the intermediate stages of the combined process are obtained by means of calculating the parameters: diameter, thickness and length of the intermediate stages completing the resolution of the process, d i ,s i ,l i iteratively obtaining d i ,s i using the mentioned parameters and l i as follows:
[0000]
l
i
-
1
=
K
π
-
d
i
-
1
2
s
n
4
-
s
i
-
1
2
s
n
+
d
i
-
1
s
i
-
1
s
n
s
i
-
1
(
d
i
-
1
-
s
i
-
1
)
l
i
=
K
π
-
d
i
2
s
n
4
-
s
i
2
s
n
+
d
i
s
i
s
n
s
i
(
d
i
-
s
i
)
l
e
,
i
=
K
π
-
d
e
,
i
2
s
n
4
-
s
i
-
1
2
s
n
+
d
e
,
i
s
i
-
1
s
n
s
i
-
1
(
d
e
,
i
-
s
i
-
1
)
if q>m q>m (deep drawing steps>ironing steps), n=q, the combined process is defined as follows:
q. the diameters obtained in the simulation of the deep drawing stages w=1 to w=n−1 are used as the initial diameters of the combined solution of the different stages,
r. the final diameter to be obtained is used as the final diameter of the stage i=n,
s. the thickness of the final part to be obtained is used as the thickness of the wall of the stage i=ni=n,
t. the thickness of the final part to be obtained is used as the thickness of the bottom of the n combined stages, and it remains unchanged throughout the entire combined process,
u. the drawing ratios obtained in deep drawing stages w=1 to w=n are used as the drawing ratios DR i ,
v. the ironing ratios K i and the diameters of the intermediate stages of the combined process are obtained by means of calculating the parameters: diameter, thickness and length of the intermediate stages completing the resolution of the process, d i ,s i ,l i , iteratively obtaining using the mentioned parameters and i as follows:
[0000]
l
i
-
1
=
K
π
-
d
i
-
1
2
s
n
4
s
i
-
1
2
s
n
+
d
i
-
1
s
i
-
1
s
n
s
i
-
1
(
d
i
-
1
-
s
i
-
1
)
l
i
=
K
π
-
d
i
2
s
n
4
-
s
i
2
s
n
+
d
i
s
i
s
n
s
i
(
d
i
-
s
i
)
l
e
,
i
=
K
π
-
d
e
,
i
2
s
n
4
-
s
i
-
1
2
s
n
+
d
e
,
i
s
i
-
1
s
n
s
i
-
1
(
d
e
,
i
-
s
i
-
1
)
[0136] As the number of stages advances from the initial stage, the selected drawing ratios are taken and the parameters of the subsequent stage are calculated. Therefore, if the drawing ratio in stage 2 , for example, is DR 2 =2 and the diameter in stage i−1=1 is 3 mm, such as
[0000]
DR
i
=
diameter
resulting
part
stage
i
-
1
diameter
part
stage
i
then
,
diameter
part
stage
2
=
diameter
resulting
part
stage
1
DR
2
=
3
2
=
Error
!
Digit
expected
.1
.5
mm
.
[0137] The following parameters are thus solved:
[0000] d i =outer diameter of the resulting part in simulation step
s i =thickness of the wall of the resulting part in simulation step i,
l i =length of the part in simulation step i.
[0138] Optimization of the Combined Simulation
[0139] The parameters obtained by means of the combined simulation process are optimized by means of a combination optimization algorithm. This algorithm is based on the resolution of a target function.
[0140] The target function minimizes the overall work performed in the optimized combined process, this function being:
[0000]
f
w
=
∑
i
=
1
n
[
blankholder
work
+
deep
drawing
work
+
ironing
work
]
==
∑
i
=
1
n
[
-
0.015
S
y
π
(
d
i
-
1
-
2
s
i
-
1
)
h
cos
(
α
)
l
i
-
1
+
[
π
(
d
i
2
s
i
)
s
i
-
1
S
u
d
i
-
1
d
e
,
i
-
0.7
]
l
e
,
i
+
π
4
(
d
e
,
i
2
-
d
1
2
)
n
e
S
u
l
i
]
[0000] with
S=yield strength limit of the material used for the simulation,
h=height of the holding or securing element
S u =tensile strength limit of the material used for the simulation,
α=angle of entry into the deep drawing die,
n e =ironing coefficient=s n /s 1 ,
d i-1 d i-1 outer diameter of the resulting part in simulation step i−1,
s i-1 =thickness of the wall of the resulting part in simulation step i−1,
l i-1 l i-1 length of the part in simulation step
d e,i intermediate diameter in simulation step
Error! Digit expected.,
where the parameters that are minimized are:
d i =outer diameter of the resulting part in simulation step
s i =thickness of the wall of the resulting part in simulation step
l i =length of the part in simulation step
[0141] In one embodiment of the invention, the following restrictions are assumed in the optimization process:
[0142] V i =V i-1 =K,
[0143] with
[0000] V i = total part volume = π 4 d i 2 l i + π 4 ( d i - 2 s i ) 2 ( l i - s n ) d i-1 −s i-1 ≦1.7 d i −3.4 s i ,
[0000] n e ( d i s i-1 −d i s i +s i-1 2 s i +s i 2 )< d i s i −s i 2 .
[0000] such that the parameters minimizing the target function and defining the optimized combined process in their entirety are obtained as a result.
[0144] Finding the parameters minimizing the function of the overall work also indirectly reduces the overall time used and the manufacturing cost, defined as:
the overall time invested in the simulation process:
[0000]
f
t
=
∑
i
=
1
n
t
i
[0000] with l i being the time used in each simulation step i for simulating the deep drawing and the ironing,
[0000]
t
i
=
l
i
-
1
v
a
,
i
+
L
u
,
i
+
l
i
v
e
,
i
+
l
i
-
1
+
L
u
,
i
+
l
i
v
s
,
i
[0000] v a,i =approach speed of the punch in simulation step
v e,i =operating speed of the punch in simulation step i,
v s,i =recovery speed of the punch in simulation step i,
L u,i =length of the tool assembly in simulation step i,
and the total process cost:
[0000]
f
c
=
C
mf
+
C
E
=
∑
i
=
1
n
(
c
l
b
t
i
+
c
e
3.6
*
10
6
W
i
)
[0000] C mf =C mf =cost of the work applied to the simulated sheet metal ( 9 ),
C E =cost of the electricity used to operate the machines used in the deep drawing and the drawing,
c lb hourly labor cost,
c e =energy cost per hour,
Wi=overall work in simulation step i.
Experimental Example of the Application of the Optimized Combined Solution
[0147] In one embodiment, the sheet metal forming method is implemented by previously carrying out the simulation and optimization processes. The manufacture of an ammunition cartridge case manufactured in UNS C26000 brass has been simulated in the complete example. Table 1 shows the final dimensions of the part to be obtained as well as the characteristics of the material used in the experiment. The friction coefficients that were used are also included.
[0000]
TABLE 1
Final dimensions and material of the experiment
Outer diameter (d n )
110.6
mm
Length (l n )
560
mm
Thickness of the bottom (s n )
7.3
mm
Thickness of the wall (e n )
1.2
mm
Material
UNS C26000
Density, ρ
8.53
Kg/dm 3
Rigid-plastic behavior constant of the
895.0
MPa
material, C
Strain hardening exponent of the material, n
0.485
Yield strength limit, S y
435.0
MPa
Tensile strength limit, S u
525.0
MPa
Normal anisotropy coefficient, R
0.83
Friction coefficient, disc-die
0.1
Friction coefficient, disc-punch
0.12
Friction coefficient, part-die
0.1
Friction coefficient, part-punch
0.12
[0148] The system consists of three parts: tool, hydraulic system and control panel. The tool is formed by a support housing the dies and the blank-holder elements. The punch is integral with the movable head of the press. Machinery operation as well as the pressure regulation, speed regulation and pressure recordings taken along the path of the punch are performed by means of the control panel ( 12 ).
[0149] As indicated in the graphs in FIGS. 4A , 4 B and 4 C, the combined deep drawing and ironing process allows reducing the overall process from seven to five steps. The drawings show the evolution of the more important dimensions of the steps: FIG. 4A shows the evolution of the outer diameter of the part that is obtained in each step in millimeters, FIG. 4B shows the evolution of the thickness of the wall of the part that is obtained in each step in millimeters, and FIG. 4C shows the evolution of the total length of the part that is obtained in each step in millimeters. It can be seen in the three figures that the new the designed process ( 15 ) shows a process that is much more compensated than the conventional process ( 14 ). The experimental results ( 16 ) comply with the theoretical design ( 15 ).
[0150] The results depicted in the graphs in FIGS. 4A , 4 B and 4 C are observed in Table 2.
[0000]
TABLE 2
Evolution of the diameter of the part obtained in each step of the process
EVOLUTION OF THE DIAMETER IN mm
step
0
1
2
3
4
5
6
7
non-combined
228
128.18
122.8
117.6
114.21
112.02
110.62
110.6
solution (14)
optimized
228
194.8
167.2
144.9
126.3
110.6
combined
solution (15)
experimental result
228
195.5
167.7
145.5
126.7
110.8
(16)
[0000]
TABLE 3
Evolution of the thickness of the wall of the part
obtained in each step of the process
EVOLUTION OF THE THICKNESS OF THE WALL IN mm
step
0
1
2
3
4
5
6
7
non-combined
7.3
7.3
7.3
4.7
3.01
1.91
1.21
1.2
solution (14)
optimized
7.3
5.16
3.4
2.3
1.6
1.2
combined
solution (15)
experimental
7.3
5.35
3.35
2.1
1.52
1.15
result (16)
[0000]
TABLE 4
Evolution of the length of the part obtained in each
step of the process
EVOLUTION OF THE LENGTH IN mm
step
0
1
2
3
4
5
6
7
non-combined
0
84.3
87.2
138.5
219. 9
349.3
554.8
560
solution (14)
optimized
0
33.5
86.1
179.5
336
560
combined
solution (15)
experimental
0
33.7
91.7
205.6
372
610
result (16)
[0151] Furthermore, as shown in FIG. 5 , the drawing ratio (DR) has similar values for the five stages designed, which shows a much more balanced process compared with the initial solution. The highest drawing ratios (DR) obtained in the first phases of the initial design ( 14 ) are reduced in the combined process ( 15 ).
[0000]
TABLE 5
Evolution of the drawing ratio (DR) in each step of the process
EVOLUTION OF THE DRAWING RATIO IN EACH STEP
step
1
2
3
4
5
6
7
non-combined
1.8215
1.0194
1.1706
1.1651
1.1539
1.1471
1.1418
solution (14)
optimized
1.1706
1.1651
1.1539
1.1471
1.1418
combined
solution (15)
experimental result
1.1662
1.1658
1.1526
1.1484
1.1435
(16)
[0152] Concerning the overall process time, a shorter overall time for the combined process with respect to the conventional process is also achieved, these values being:
Conventional process time: 35.45 seconds, Estimated time in the simulation of the combined process: 26.21 seconds, Time used in the experiment: 27.53 seconds.
[0156] These times are obtained with the aforementioned ratio:
[0000]
f
t
=
∑
i
=
1
n
t
i
where
t
i
=
l
i
-
1
v
a
,
i
+
L
u
,
i
+
l
i
v
e
,
i
+
l
i
-
1
+
L
u
,
i
+
l
i
v
s
,
i
.
[0157] According to the results obtained, a 26% improvement of the combined process is achieved with respect to the initial solution. With respect to the experimental result, there is a 22.34% improvement, so a 95.2% validation degree is obtained for the model with respect to the experimental solution.
[0158] Concerning the overall work used in the process, the following values are achieved:
conventional work process: 648.9 KJ estimated work in the simulation of the combined process: 543.55 KJ), work used in the experiment: 566.99 KJ.
[0162] The overall work performed is obtained with the aforementioned ratio:
[0000]
f
w
=
∑
i
=
1
n
[
blankholder
work
+
deep
drawing
work
+
ironing
work
]
==
∑
i
=
1
n
[
-
0.015
S
y
π
(
d
i
-
1
-
2
s
i
-
1
)
h
cos
(
α
)
l
i
-
1
+
[
π
(
d
i
2
s
i
)
s
i
-
1
S
u
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[0163] According to the obtained results, a 16.23% improvement in the work performed through the optimized combined process is achieved with respect to the non-combined solution. Comparatively speaking, between the non-combined solution and the experimental result there is a 12.62% improvement. These results show a 95.86% validation of the experimental result with respect to the solution of the optimized combined simulation process that has been designed.
[0164] FIG. 6 depicts a flowchart of all the operations carried out in an embodiment of an optimized combined simulation process:
1. Simulation without simultaneously combining deep drawing and ironing stages: Simulation stage of the deep drawing steps. 2. Simulation without simultaneously combining deep drawing and ironing stages: Simulation stage of the ironing steps. 3. Combined simulation. This stage seeks a number of stages that combine simultaneous deep drawing and ironing operations, even though they may not be optimal. 4. Optimized combined simulation. In this stage, the dimensions of the tools and elements are calculated such that the overall work performed is reduced, as indicated in the example.
[0169] The optimization stage is optional and can be applied in the event of needing a combined process the parameters of which must be optimized to reduce the overall work performed. | The invention relates to a method and system for forming a metal sheet, preferably in the form of a disc, in order to obtain an essentially cylindrical and essentially hollow end metal part having a base thickness that is essentially greater than the thickness of its walls. More specifically, the invention relates to the metalworking sector and, in particular, to the production of ammunition cases or shells. | 5 |
TECHNICAL FIELD
This disclosure relates to flexible and printable nonwoven substrates having high air- and steam-permeability, heat stability, and bacterial impermeability, for use in forming packages for instruments, devices, appliances and the like that require sterilization by various methods including heat, ethylene oxide and gamma radiation, and related methods of manufacture.
BACKGROUND OF INVENTION
Many types of instruments, devices, appliances and the like including, for example, surgical and other medical instruments (collectively “instruments”) must be sterilized prior to use. Typically, such instruments are packaged, sealed and sterilized in disposable packaging so they can be safely transported and stored until they are used. Several sterilization techniques are known in the art, including gamma radiation, steam, dry heat and ethylene oxide sterilization techniques. In general, a sterilizing gas, vapor or liquid flows through pores in the disposable packaging and sterilizes the instruments contained therein. The sterilizing gas, vapor or liquid dissipates from the package also through the package's pores.
To form such a disposable package, an instrument may be placed between two layers of paper or plastic substrate, at least one of the layers being impervious to bacteria and debris while also being permeable to gases or steam, and the layers are sealed together to form a bag or pouch. A pouch or bag may also be formed from a paper or plastic substrate prior to inserting an instrument therein with a flap at or near an opening in the pouch such that the flap may be folded over and sealed to the pouch with an adhesive or other type of known sealing method. Alternatively, an instrument may be placed in a paper or plastic tray, sometimes molded to the shape of the instrument, and then covered and sealed with at least one layer of paper or plastic substrate that is both impervious to bacteria and debris, and permeable to gases or steam.
Substrates useful to form such packaging should exhibit sufficient airflow through the material to relieve pressure in the package during sterilization, high steam permeability, resistance to high temperatures, and should provide a significant barrier to penetration by bacteria and debris. It is also desirable that a substrate for this purpose be flexible, strong, printable, and sealable to itself and thermoplastic films and substrates. Other desired characteristics depend on the particular product disposed within the packaging.
An example of a commonly used medical packaging material is a high strength barrier nonwoven composed entirely of flash-spun polyolefin (usually high density polyethylene) sold under the trademark TYVEK® by E.I. DuPont De Nemours & Co. and described in U.S. Pat. No. 3,169,898 to Steuber. Although TYVEK® fabric is micro-porous and acts as a barrier to particulate matter that is sub-micron in size, TYVEK® fabric has very low air and gas permeability (i.e., high resistance to air and gas permeation), making the penetration of ethylene oxide and steam, and their subsequent off-gassing difficult and time consuming. TYVEK® fabric also has poor printability due to its inherent low surface energy and suppleness, and must be treated and/or coated to improve printability. Further, TYVEK® fabric has a relatively low melting point (approximately 130° C.) and will severely deform and shrink under high temperature sterilization techniques such as steam, which is typically conducted at temperatures greater than 135° C.
Barrier fabrics have been developed using wet-laid processing techniques, and often include 100% wood pulp, which is wet-laid on a Fourdrinier machine, saturated with latex and highly calendered. In the medical industry, these barrier fabrics are commonly referred to as “medical packaging paper.” Wet-laid barrier fabrics made from other fibers are disclosed in U.S. Publication No. US 2010/0272938 A1, published Oct. 28, 2010. However, wet-laid nonwovens typically do not have sufficient barrier properties to prevent bacteria and debris from penetrating through the fabric, and also lack sufficient strength for packaging instruments.
Barrier properties of a porous packaging material (i.e., the ability to resist the passage of microorganisms) are measured using ASTM Standard F1608, “Standard Test Method for Microbial Ranking of Porous Packaging Materials (Exposure Chamber Method),” and result in a “Log Reduction Value” for a material. The higher the Log Reduction Value, the more effective a material is at filtering out bacteria. For example, medical grade TYVEK® fabric has a Log Reduction Value of 5. Wet-laid nonwovens and papers typically have a Log Reduction Value between 1 and 2.5. Wet-laid nonwoven fabrics containing cellulosic fibers can improve their barrier properties by using highly refined pulps, calendering and/or selecting shorter and thinner walled hardwood fibers, but these modifications also weaken the physical strength (i.e., tear strength) of the fabric, reduce opacity and increase stiffness. Cellulosic fibers also tend to weaken and discolor during certain sterilization techniques such as steam and ethylene oxide sterilization.
It is therefore an object of this disclosure to overcome the foregoing difficulties such as those associated with TYVEK® medical grade fabric and cellulosic wet-laid nonwovens and papers, and provide a nonwoven substrate that exhibits high strength and that can withstand higher temperatures than TYVEK® medical grade fabric, is steam sterilizable, has sufficient airflow to relieve pressure in the package during sterilization, provides a significant barrier to penetration by bacteria and debris, is sealable to itself and thermoplastic films and substrates, and is printable.
SUMMARY OF INVENTION
The foregoing purposes, as well as others that will be apparent, are achieved generally by providing a nonwoven substrate in the form of a wet-laid fibrous sheet comprising a low porosity top layer for barrier and printing properties and a high strength bottom layer. The top layer comprises nanofibrillated lyocell fibers. The bottom layer comprises a blend of microfibers, fibers having a flat, rectangular cross-section, binder fibers, first polymeric fibers having a first linear density and a first length and second polymeric fibers having a second linear density and a second length both greater than the first linear density and first length of the first polymeric fibers. In a preferred embodiment, the top layer further comprises microfibers; and, in another preferred embodiment, the top layer further comprises fibers having a flat, rectangular cross-section.
The fibers having a flat, rectangular cross-section are preferably splittable conjugated fibers, which have an ultra-fine structure that provides improved strength, tear resistance, and barrier properties. The splittable conjugated fibers are synthetic (preferably polyester and nylon), and are characterized by high melting points, allowing them to be sterilizable at high temperatures and, in particular, allows for steam sterilization. Preferred splittable conjugated fibers have a sectional cross-section that splits into ribbon-like fibers after fibrillation, mimicking some cellulosic fibers, and, more particularly, have a sectional cross section that is generally rectangular in shape. Such fibers are generally extruded in a cylindrical shape and split into ribbon-like fibers with varying widths and slightly curved ends.
After formation of the substrate or sheet by a wet-laid process, the sheet may be fused using a thru-air drier, an infrared drier, a gas oven, or a thermally heated calender. If a thermally heated calender is used, temperatures of approximately 150° C. and pressures of approximately 500 to 1500 pounds per square inch can sufficiently fuse the web. The advantage of a thermally heated calender to fuse the binder fibers is that it provides greater compaction of the sheet (i.e., improved barrier) compared to other methods. The fused and dried sheet is then subjected to treatment with an aqueous binder composition preferably comprising a styrenated acrylic having a glass transition temperature between 20° C. and 40° C.
Preferred blends of fibers include: (i) a bottom layer of 10 to 30% by weight of polyester microfibers, 0 to 20% by weight of splittable conjugated fibers, 5 to 15% by weight of binder fibers having a melt temperature greater than 140° C., 0 to 20% by weight of the first polymeric fiber, and 10 to 40% by weight of the second fiber; and (ii) a top layer of 40 to 80% by weight of fibrillated lyocell fibers and 20 to 60% by weight of either polyester microfiber or splittable conjugated fibers.
The nonwoven substrate may have a total weight of about 65 to about 113 grams per square meter, and should be sufficiently porous to allow the appropriate permeability to air, gas and steam while maintaining resistance to undesirable contaminants such as bacteria and debris. The average pore size of a layer or layers depends on the overall basis weight and spatial density of the substrate, the composition of fiber morphologies (shape and coarseness) making up the substrate and relative ratio of the weight of the top phase to the weight of the bottom phase, bearing in mind that the size of bacteria is generally from 0.5 to 5 micron (or micrometers, μm), and is preferably in the range of 0.25 to 11 micrometers. The average pore size may be measured using a capillary flow porometer (such as those available from Porous Materials, Inc., Ithaca, N.Y.).
Strength, porosity and permeability characteristics are imparted to the nonwoven substrates disclosed herein by the combination of synthetic fibers employed in the fiber blend. For example, the substrate has a preferred combination of properties including Gurley porosity value of at least 13 seconds per 100 milliliters and Elmendorf tear strength of greater than 400 grams in both the cross direction and machine direction. The substrate also exhibits a Log Reduction Value greater than 2 and dry process tensile strengths of at least about 10,000 grams per 25 millimeters in the machine direction and at least about 6,000 grams per 25 millimeters in the cross direction.
Preferred fiber blends maintain balance between strength, barrier properties and cost. For example, increasing the amount of lyocell fibers in the blend generally increases the resulting substrate's barrier properties, and increasing the amount of microfibers or splittable conjugated fiber in the blend generally increases the substrate's strength and dimensional stability.
Additional fibers, materials and layers may be added to the nonwoven substrate to impart other properties. Other objects, features and advantages of the present disclosure will be apparent when the detailed description of preferred embodiments is considered in conjunction with the following drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a scanning electron micrograph (or SEM) of the top surface of a first embodiment of an untreated exemplary nonwoven substrate with 425 times magnification.
FIG. 2 is an SEM of the top surface of a second embodiment of an untreated exemplary nonwoven substrate with 385 times magnification.
FIG. 3A is an illustration of an apparatus for forming an aqueous suspension of fibers for use in manufacturing a wet-laid nonwoven substrate.
FIG. 3B is an illustration of an alternative apparatus for forming an aqueous suspension of fibers for use in manufacturing a wet-laid nonwoven substrate.
FIG. 4A is an illustration of an apparatus for manufacturing a wet-laid nonwoven substrate.
FIG. 4B is an illustration of an alternative apparatus for manufacturing a wet-laid nonwoven substrate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Preferred nonwoven substrates that exhibit the desired characteristics of improved strength, bacterial barrier, tear resistance, flexibility, printability, stability during steam sterilization, air and steam permeability, heat resistance, sealability and high melting point comprise at least two layers and are produced via a wet-laid process on an inclined wire (or combination of inclined wire and Fourdrinier as in a twin wire process shown in FIG. 3A ), dried and fused (optionally using a heated calender for added compaction), and treated with an aqueous binder composition. A top layer comprises nanofibrillated lyocell fibers. A bottom layer comprises a blend of microfibers, fibers having a flat, rectangular cross-section, binder fibers, first polymeric fibers having a first linear density and a first length and second polymeric fibers having a second linear density and a second length both greater than the first linear density and first length of the first polymeric fibers.
The top layer further comprises either microfibers or fibers having a flat, rectangular cross-section. FIGS. 1 and 2 are SEMs of two preferred top layers of the substrate. FIG. 1 shows a top layer comprising nanofibrillated lyocell fibers 12 and fibers having a flat, rectangular cross-section 14 . FIG. 2 shows a top layer comprising nanofibrillated lyocell fibers 12 and microfibers 16 .
The fibers selected for use in preferred nonwoven substrates disclosed herein are synthetic fibers. As used in this application, the term “synthetic fibers” are fibers that are formed through a melt extrusion process (i.e., fiber pellets are dissolved and extruded as a continuous filament) to permit control of the length, shape and morphology of the extruded fiber. Synthetic fibers include lyocell fibers, but do not include natural cotton, wool or pulp fibers. Preferred nonwoven substrates disclosed herein comprise 100% synthetic fibers.
The diameter or linear density of a fiber may be measured in units of micron or denier per filament. The unit micron is equivalent to the unit micrometer, and represents one-millionth of a meter (or 1/1000 of a millimeter or 0.001 mm). Denier per filament (or dpf) is the denier of a fiber divided by the number of filaments in the fiber. Denier is the weight in grams of 9,000 meters of fiber. Linear density may also be measured in Decitex (or dtex), which is the weight in grams of 10,000 meters of fiber. To convert from dtex to denier, the following formula may be used: denier=0.9×dtex. The ratio of fiber length to fiber diameter is referred to as the “aspect ratio” of the fiber.
The term “microfibers”, as used herein, refers to fibers having a diameter less than 5 micron and a length of less than 3 millimeters. Preferred microfibers 16 are polyester (PET) microfibers having a non-splittable, cylindrical cross-section, and act as a processing aid in the wet-laid forming process, permitting processing of 100% synthetic compositions without specialized handling or processing equipment and also providing wet strength. A preferred microfiber 16 is a PET microfiber available from Eastman, Kingsport, Tenn., having a 2 to 4 micron (micrometer) diameter and length of about 1.5 millimeters. The Eastman PET microfibers are extruded “islands-in-the-sea” (IS) fibers made from a proprietary water dispersible polyester resin. They are available in diameters of 2 to 4 micron and can be chopped to desired length between 1.5 and 3 millimeter, and then processed to dissolve the sea portion of the fibers and leave the islands portion of the fibers.
As an alternative, polyvinyl alcohol (PVA) binder fibers can be used as a processing aid and to provide wet strength instead of the microfibers. For example, a PVA fiber available from Kuraray Co., Ltd., Osaka, Japan under the designation PV105-2 may be used to perform a similar processing function. However, use of a microfiber of similar polymer chemistry permits forming a substrate with a homogeneous fiber matrix, which may be useful for recycling at end of use.
In preferred embodiments, microfibers should be present in the bottom layer in an amount of about 10% to 30% by weight of the bottom layer. Weight measurements throughout this specification are measured in the dry state. When microfibers 16 are used in the top layer, they should be present in an amount of about 20% to 60% by weight of the top layer.
Fibers having a flat, rectangular cross-section 14 are useful in wet-laid nonwovens because their flat surfaces permit such fibers to cover holes resulting from the forming process, and thus improve barrier properties of nonwoven substrate. It has been found that increasing the amount of such flat, rectangular fibers 14 in a fabric results in increased barrier properties (relative to the use of other short cut staple fiber synthetic fibers). Preferred flat fibers are splittable conjugated fibers or standard flat polyester fibers. Conjugated fibers are those that have two different polymers within the fiber. A conjugated fiber is splittable when the two different polymers have little cohesion between the fibers. Preferred Splittable conjugated fibers 14 have a sectional cross-section that splits into multiple ribbon-like fibers (mimicking some cellulosic fibers). See FIG. 1 . For example, a conjugated fiber of nylon and polyester is easily separated and useful in the preferred nonwoven substrates. Such splittable conjugated fibers have an ultrafine structure that, after fibrillation, provides good barrier properties similar to refined pulp, but also imparts improved strength, dimensional stability, and good drainage. Fibrillation of the splittable conjugated fiber occurs during the wet-laid process from shearing forces resulting from the mechanical action (or turbulence) under dilute conditions, which are sufficient to spontaneously split the conjugate fibers during the wet-laid process.
In preferred embodiments, conjugated fibers 14 should be present in the bottom layer in an amount of about 0% to 20% by weight of the bottom layer. When conjugated fibers 14 are used in the top layer, they should be present in an amount of about 20% to 60% by weight of the top layer.
A preferred conjugated polyester/nylon short-cut fiber is available from Kuraray Co., Ltd., Osaka, Japan under the trade name WRAMP, Solid Core Type, which has a linear density of 3.3 dtex (2.97 denier) before split and length of 3-10 millimeters. The linear density after split is approximately 0.3 dtex (0.27 denier). The WRAMP fiber has a split number of 11 (6 polyester/5 nylon). WRAMP fibers provide substrates with high tear factor, low air permeability, smaller pore size, high luster and high folding capacity. Kuraray WRAMP splittable conjugated fibers also have a high melting temperature, which makes them steam sterilizable.
Binder fibers useful in the bottom layer should have a high melting temperature, 140° C. or higher, and may be formed from polyacrylate, styrene-butadiene copolymer, polyvinyl chloride, ethylene-acrylate copolymer, vinyl acetate-acrylate copolymer and coPET binders. Preferred binder fibers are bi-component fibers of the type having an outer sheath and a core. An example of such a bi-component binder fiber is the high temperature copolyester binder fibers (copolyester/polyester), Type TJ04BN supplied by Teijin Fibers Limited, Osaka, Japan having linear density of 1.7-3 dtex (1.53-2.7 denier), length of 5-15 millimeters, and sheath melting temperature of about 150° C. Other examples of binder fibers that may be used include Type 7080 crystalline bicomponent coPET/PET fibers, available from Unitika Fibers Ltd., Osaka, Japan, having a linear density of 2.0 denier, a length of 5 mm and a sheath melt temperature of 160° C.) and Kuraray Type N720H (melting temperature 150° C.). In preferred embodiments, binder fibers should be present in the bottom layer in an amount of about 5% to 15% by weight (in dry state) of the bottom layer.
Preferred nanonfibrillated lyocell fibers 12 used in the substrate are fibers formed by dissolving and extruding naturally occurring cellulosic materials, such that the chemical nature of the naturally occurring cellulosic material is retained after the fiber formation process, and the length, diameter and morphology of the extruded fiber may be controlled. Therefore, preferred lyocell fibers are synthetic fibers as defined herein.
During fiber formation, lyocell fibers 12 typically fibrillate, or form micro-fibrils or nano-fibrils on the fiber surface, and fill in gaps in the top layer left by the conjugated fibers 14 or microfibers 16 during wet-laid processing, as shown in FIGS. 1 and 2 . A preferred lyocell fiber is a nano-fibrillated fiber available from Engineered Fibers Technology in Longmeadow, Mass. under the trademark EFTec 010-4. Other nano-fibrillated lyocell fibers may also be used. In preferred embodiments, lyocell fibers 12 should be present in the top layer in an amount of about 40% to 80% by weight of the top layer.
The remaining fibers in the fiber blend of the bottom layer are preferably polymeric fibers of varying linear density and length. For example, a first fiber may be a short-cut polyester fiber having a liner density of 1.7 dtex (1.53 denier) and a length of about 5-15 mm, such as a 10 millimeter 100% Post Consumer recycled polyester fiber (“EcoPET”) from Teijin Fibers Limited, Type TA4 may be used, or alternatively a 10 millimeter Kuraray EP303, or Teijin's virgin 10 mm TA04N fiber may be used. Such a fiber may be present in the amount of about 0% to 20% of the bottom layer. A second polymeric fiber used in the bottom layer may be a standard polyester fiber having a linear density of 1.5-6.0 dtex (1.35-5.4 denier) and length of 15-25 millimeters. For example, a polyester fiber from William Barnet & Sons, LLC, Product No. P50FM may be used (a High Tenacity fiber 5.2 dtex/19 millimeter). Such a fiber may be present in the amount of about 10% to 40% of the bottom layer.
The weight of the top layer is preferably in the range of about 10 to 25 grams per square meter, and the weight of the bottom layer is preferably in the range of about 40 to 60 grams per square meter. The bottom layer is typically heavier than the top layer by about 2 to 3 times. Preferably, the weight ratio of top layer to bottom layer is about 1 to 2.5. A higher weight ratio of top layer to bottom layer, or using a more massive top layer for a given bottom layer, will produce a more closed and higher barrier substrate. If the weight ratio of top layer to bottom layer is changed, without changing the total basis weight of the combined layers, increasing the ratio will decrease the strength of the substrate and improve barrier properties. To increase strength properties, the weight of the bottom layer should be increased.
A first exemplary fiber blend for a two-layer nonwoven substrate in accordance with the foregoing disclosure is set forth in TABLE I, and referred to herein as Example 1.
TABLE I
Fiber Composition of Two-Layer Structure - 10242011-1B
Aspect
Diameter or
Length
Weight
Ratio
Component
Brand
Linear Density
(mm)
(%)
(L/D)
TOP LAYER (Weight - 20 gsm):
PET/Nylon
Kuraray
3.3 dtex (2.97
5
40
893
Conjugated
WRAMP
denier)
Fiber
(before split)
Fibrillated
EFTec
nanofibrillated
4
60
Lyocell
010-04
BOTTOM LAYER (Weight - 44 gsm):
PET
Eastman
1.5 micron
1.5
20
1000
Microfiber
Microfiber
PET/Nylon
Kuraray
3.3 dtex (2.97
5
10
893
Conjugated
WRAMP
denier)
Fiber
(before split)
CoPET/PET
Teijin
2.2 dtex (1.98
5
10
357
Binder Fiber
TJ04BN
denier)
Polyester
Teijin TA4
1.7 dtex (1.53
10
20
12000
Fiber
denier)
Polyester
Barnet
5.2 denier
19
40
712
Fiber
P50FM -
High
tenacity
A second exemplary fiber blend is set forth in TABLE II, and referred to herein as Example 2.
TABLE II
Fiber Composition of Two-Layer Structure - 10242011-2B
Aspect
Diameter or
Length
Weight
Ratio
Component
Brand
Linear Density
(mm)
(%)
(L/D)
TOP LAYER (Weight - 20 gsm):
PET
Eastman
1.5 micron
1.5
40
1000
Microfiber
Microfiber
Fibrillated
EFTec
4
60
Lyocell
010-04
BOTTOM LAYER (Weight - 44 gsm):
PET
Eastman
1.5 micron
1.5
20
1000
Microfiber
Microfiber
PET/Nylon
Kuraray
3.3 dtex (2.97
5
10
893
Conjugated
WRAMP
denier)
Fiber
(before split)
CoPET/PET
Teijin
2.2 dtex (1.98
5
10
357
Binder Fiber
TJ04BN
denier)
Polyester
Teijin TA4
1.7 dtex (1.53
10
20
12000
Fiber
denier)
Polyester
Barnet
5.2 denier
19
40
712
Fiber
P50FM -
High
tenacity
The specific ratio of fibers in the fiber blends of preferred nonwoven substrates varies depending on what specific material properties are required. Employing the appropriate mix of synthetic fibers permits tuning the fiber matrix to the desired porosity and barrier characteristics, while taking into account cost considerations. In general, a double layer substrate is more cost effective because it allows a thinner, but higher concentration of fine fibers (higher barrier) within a layer, thus using fewer specialty fibers. If a high barrier property is required (i.e., bacterial barrier), greater amounts of lyocell fibers should be used, while substituting conjugate or microfiber fibers for lyocell fibers will render a slightly more porous sheet. However, too much lyocell makes it difficult for water to drain from the substrate during production and will require slower production speeds. Tuning the amount of lyocell fibers within the ranges set forth in this application will prevent this problem, and represents a level of good runnability (i.e., faster processing speeds and fewer breaks) and performance.
If the nonwoven substrate is produced in a two-layer structure, one layer can be designed specifically for barrier properties and the other layer can be designed to provide strength. This type of construction permits one to minimize fiber costs.
Although preferred embodiments are described as a double-layer construction, the nonwoven substrate is not limited to the use of only two layers. The grammage and characteristics of the various sheets may be adjusted according to the general teachings of the present disclosure. For example, a three-layer substrate may be formed having a high barrier central layer that is not as strong and two outer layers that exhibit strength, or a high barrier central layer may be sandwiched between an outer layer with good sealing properties and an outer layer with high printability.
Nonwoven substrates that exhibit the desired characteristics of improved strength, bacterial barrier, tear resistance, flexibility, printability, stability during steam sterilization, air (and steam) permeability, heat resistance, sealability and high melting point, may be produced by conventional wet-laid processes, preferably using an inclined wire machine.
Referring to FIGS. 3A and 3B , at least two suspensions of fibers are prepared by filling hydropulpers 20 , 22 with warm water, agitating the water, adding a blend of fibers as set forth above, and further agitating the mixture for approximately 2 to 20 minutes to mix the fibers and create a fiber slurry. For example, the fibers used for bottom layer are mixed in hydropulper 20 and the fibers used for the top layer are mixed in hydropulper 22 . Each of the fiber slurries is then transported to a mixing chest 24 , 26 to further mix the fibers of each blend, and then to a blending chest to dilute the fiber slurry to the desired consistency of 0.2% to 0.4%. Fibrillation of the splittable conjugated fiber occurs in this part of the wet-laid process. The hydropulpers 20 , 22 and mixing chests 24 , 26 apply sufficient shearing forces resulting from the mechanical action (or turbulence) under dilute conditions to spontaneously split the conjugate fibers. Heating the water to about 40-80° C. and/or hydroentanglement may also aid in splitting the fibers, but are not necessary.
When the fiber slurries are sufficiently mixed and diluted, each of fiber slurries is transported to a headbox 28 , 30 for delivery to the web-forming machine, where the fiber slurries are dewatered on an inclined wire forming line 32 to form a multi-layer sheet. Referring to FIG. 3A , the top layer may be formed on a separate wire 34 (which, in this twin wire configuration, could alternatively be a Fourdrinier style former), and then placed on top of the bottom layer while the bottom layer is traveling up the inclined wire forming line 32 . Alternatively, the bottom layer and top layer may be placed onto the inclined wire forming line 32 successively, as shown in FIG. 3B . Thus, each layer may be formed separately on a wire and then combined to form the substrate, or the bottom layer may be formed on the wire, and the top layer may be formed directly on the bottom layer.
After the substrate is formed from the fiber blends, the formed sheet may be dried and fused as shown, for example, in the process lines of FIGS. 4A and 4B . FIG. 4A shows a process of using a heated calendering step for fusing and consolidation. FIG. 4B shows a process of using a thru air drier 48 for fusing the binder fibers instead of the heated precalender 38 shown in FIG. 4A . Other means of fusing the fibers may also be used, such as infrared, or gas ovens.
In the case of FIG. 4A , a calendering process may be introduced to fuse the sheath of the bicomponent binder fibers to the other synthetic fibers, to render the surface smooth, decrease its permeability (via densification) to the desired target, and achieve a porosity value lower than 20 L/min/100 cm 2 as measured by the testing method described in TAPPI T251 (before treatment). This test measures the air permeability of a square centimeter of fabric, or the volume of air that flows through the fabric per minute. The calender section may have single or multiple nip configurations for web consolidation. Calendering may be done on-line or off-line, but it is preferable to have it in-line. The calendering process should minimize any disruption or degradation of the bottom surface of the bottom layer. This can be accomplished by exposing only the top of the sheet to heat and pressure, and the bottom of the sheet only to pressure. For example, a heated steel roll and a non-heated rubber lower roll can be employed. Preferred calendering pressures vary between 300 and 2,000 pounds per square inch, preferably 500-1,500 pounds per square inch. Preferred temperatures of the top roll vary between 250-350° F., preferably 295° F., depending on the type of fibers that are used in the fiber blend.
Referring to FIG. 4A , the formed substrate sheets may be transferred from the inclined wire forming line 32 to a first drying section comprising a series of drying cans 36 to remove water. Then, the formed substrate sheets may be transferred to a heated precalender section 38 for fusing the binder fiber.
Various binders may then be applied to the formed sheet in aqueous form to further improve strength and barrier properties. The aqueous binder treatment is preferably applied after calendering the sheet, and may be provided on-line or off-line, to further enhance final product properties, such as increasing the density of the sheet, developing inter-fiber bonding and strength. A saturating size press 40 or other conventional means may be used to apply the binder.
Acceptable aqueous binders include, but are not limited to: styrenated acrylic (for example, BASF nx-4787), coPET (for example, Eastman 1200), acrylic (for example, Eco 100 Dow), polyurethane (for example, Permax 202), styrene-butadiene copolymer (for example, GenFlo 3060), acrylic copolymer (for example, BASF 4612), or combination there of (either sequentially added to the web or as a single mixture). The binder should have a glass transition temperature in the range of about +20° C. to +40° C. The aqueous binder is used in combination with the binder fibers to develop interfiber bonding and strength. Additionally, the aqueous binder boosts strength and ties down the fibers to limit the amount of fibers raised above the surface of the substrate.
The aqueous binder may be applied as an add-on to the substrate in an amount equal to about 15 to 28 grams per square meter. In the exemplary embodiments shown above, about 18 grams per square meter of aqueous binder were applied, but the application amount could range from between 15% to 36% add-on depending on the basis weight of each layer of the substrate. The total weight of the nonwoven substrates in this disclosure, including the aqueous binder treatment, will be about 65 to about 113 grams per square meter
Water may then be removed from the calendered sheet by passing the sheet through a second drying section 42 comprising drying cans or a through-air dryer to permit the aqueous binder treatment to cure. Additional soft calendering 44 may be applied to further smooth the surface, decrease its permeability (via densification) to the desired target, and achieve a porosity value of less than 5 L/min/100 cm 2 as measured by the testing method described in TAPPI T251 (after treatment). This test measures the air permeability of a square centimeter of fabric, or the volume of air that flows through the fabric per minute. The calender section may have a single or multiple nip configurations for web consolidation. Calendering may be done on or off-line, but it is preferable to have it in-line. The post calendering process should again minimize any disruption or degradation of the bottom surface of the bottom layer fiber matrix. This can be accomplished by exposing only the top of the sheet to heat and pressure, and the bottom of the sheet only to pressure. For example, a heated steel roll and a non-heated rubber lower roll can be employed. Preferred calendering pressures vary between 300 and 1,500 pounds per square inch, preferably 500-1,000 pounds per square inch. Preferred temperatures of the top roll vary between 200-300° F., preferably 250° F., depending on the type of binder(s) used in the aqueous binder treatment.
Post treatment soft calendering is beneficial, but is not required. The calendered substrates may then be further processed (for example, slitting) and wound to a roll in the rewind section 46 .
In an alternative process shown in FIG. 4B , a thru air drier 48 may be used for fusing the binder fibers instead of the heated precalender 38 shown in FIG. 4A . In this embodiment, the binder fibers in the formed substrate sheets are fused and the sheets are then dewatered in the first drying section 36 . One advantage of this process is that it is immediately adaptable to production lines (inclined wire) currently using through-air dryers, infrared, or gas ovens for binder fiber fusing. Most production lines do not use thermal calendering for fusing or densification purposes.
The nonwoven substrates described above exhibit improved porosity, strength and barrier properties as compared to TYVEK® and commercially available wet-laid medical papers. For example, preferred substrates have a Log Reduction Value of 2 or greater, as measured in accordance with ASTM Standard F1608, but also have improved airflow permeation resistance and strength. Airflow permeation resistance is measured by a Gurley densometer in accordance with TAPPI T460 standard test method, and measures the amount of time it takes (in seconds) for 100 milliliters of air to pass through a sample. For barrier applications, it is better for airflow permeation resistance to be higher. Elmendorf tear strength measures the force it takes to tear a 4 by 2 inch sample of a material in grams in accordance with TAPPI T414 standard test method. Higher values represent stronger substrates. Nonwoven substrates according the present disclosure have an airflow permeation resistance of at least 13 seconds per 100 milliliters and Elmendorf tear strength of at least 400 grams in both machine direction and cross direction. Preferred substrates also have a dry process tensile strength of at least about 10,000 grams per 25 meters in the machine direction and at least about 6,000 grams per 25 millimeters in the cross direction, as measured by TAPPI T494 standard test method.
The nonwoven substrates disclosed herein are also able to withstand higher temperatures than TYVEK® and are more durable than conventional medical packaging paper, such as the medical packaging paper available from Kimberly Clark as 52# Medical Packaging Paper, Type S-60857 (“KC S-60857”). The physical properties of Examples 1 and 2 compared to similar physical properties of TYVEK® and KC S-60857 are shown in Table III.
TABLE III
Physical Properties
TYVEK ®
KC
Properties
Units
Test Method
Example 1
Example 2
1074B
S-60857
Basis Weight
g/m 2
82.3
83.5
74
85
Ta2 Thickness
Microns
TAPPI T411
220
203
185
105
Airflow
S/100 ml
TAPPI T460
13
20
22
7
Permeation
(Gurley
Resistance
Densometer)
MD Dry
g/25 mm
TAPPI T494
12000
12500
12500
12000
Tensile
Strength
CD Dry
g/25 mm
TAPPI T494
7800
7600
14200
9000
Tensile
Strength
MD Elmendorf
g
TAPPI T414
723
712
380
100
Tear Strength
CD Elmendorf
g
TAPPI T414
650
646
430
150
Tear Strength
MD Elongation
%
TAPPI T494
19
18
24
8
CD Elongation
%
TAPPI T494
18
18
26
12
LRV
Log
ASTM F1608
2.9
N/A
5.3
2
Tests of the porosity of the top layer of Examples 1 and 2 prior to calendering show that greater than 17 liters of air flow through a square centimeter sample of the top layers per minute, as measured by the standard test method of TAPPI T251. The top layer in Example 1 has a porosity of 17.71/m/100 cm2 and the top layer in Example 2 has a porosity of 20.7 l/m/100 cm2 (untreated). This shows that the top layers provide good barrier properties even without binder treatment.
The data shows that nonwoven substrates manufactured as set forth herein are steam sterilizable and sufficiently porous to allow gases to escape, while providing adequate bacterial protection and strength. In addition to the foregoing properties, because the nonwoven substrates do not include any wood pulp, the substrates will not yellow during sterilization or ultraviolet exposure. The substrates also have good uniformity and are printable via flexographic, lithographic, offset and gravure printing methods without the need for expensive ink drying accelerants to cure the ink onto the surface. It is believed this results from the use of fibers that have inherently higher surface energy than high-density polyethylene used in TYVEK® products.
The above disclosure, embodiments and examples are illustrative only and should not be interpreted as limiting. Modifications and other embodiments will be apparent to those skilled in the art, and all such modifications and other embodiments are intended to be within the scope of the present invention as defined by the claims. | Sterilizable and printable, wet-laid non-woven substrate exhibiting high-strength and temperature resistance above 140° C., providing sufficient airflow to relieve pressure in a package formed from the substrate during sterilization, providing a significant barrier to penetration by bacteria and debris, and which is sealable to itself and to thermoplastic films, comprises blends of nanofibrillated lyocell fibers, microfibers, fibers having a flat, rectangular cross-section and binder fibers. | 3 |
FIELD OF THE INVENTION
[0001] This invention relates to non-intrusive techniques for monitoring the integrity of rotating mechanical components. More particularly, the present invention relates to a method and apparatus for monitoring the mechanical integrity of rotating components of a machine by monitoring the pressure fields generated by the rotating components.
BACKGROUND OF THE INVENTION
[0002] The recent deregulation in the power-generation industry has resulted in the formation of a spot market in electricity, wherein, during periods of heavy demand, the price offered for this commodity may be temporarily elevated by an order of magnitude over common levels. Recently, this approach has allowed the owners of several new power generation plants to literally pay for those assets in a short period of time. Consequently, the spot market, and end users desire to service the power generation market placed an added emphasis on the availability and reliability of the equipment to ensure that it is operational and available to meet the periods of peak demand. This scenario is true and equally applicable to other industries.
[0003] During operation of power generation equipment, several factors may likely lead to faults, thus causing machinery breakdown. Damage to compressor blades because of resonant (high-cycle fatigue) blade failures, foreign object damage (FOD), blade tip/casing rubs, and the like lead to compressor inefficiency and forced outages.
[0004] Land-based gas turbines used for power generation a compressor must be allowed to operate at a higher pressure ratio in order to achieve a higher machine efficiency. A compressor stall, as identified above with respect to aircraft turbines, may also occur in land-based gas turbines. Similar to the problems faced during the operation of aircraft gas turbines, if a compressor stall remains undetected and permitted to continue, the combustor temperatures and vibratory stresses induced in the compressor may become sufficiently high to cause damage to the turbine.
[0005] Thus, there is a need for a method and apparatus to non-invasively monitor the integrity of machinery components to determine the cause of performance degradation without disassembling the entire machinery.
BRIEF SUMMARY OF THE INVENTION
[0006] Accordingly, the present invention is directed to a method and apparatus for non-invasively monitoring the integrity of an axial flow compressor by measuring the pressure fields generated by rotating compressor blades. A plurality of sensors are disposed about the compressor casing for measuring the pressure fields generated by each of the rotating blades of a blade row, the measured pressure field indicative of the integrity of the blade.
[0007] In one embodiment, the measured pressure signature from a single sensor is compared with respective baseline reference pressure signature to identify deviations from the reference values. Deviations in the measured contours are identified to determine faults in rotating components of the compressor. The present invention adds granularity to the concept of non-invasive monitoring by ascertaining the root cause of changes in performance without disassembly of operating machinery.
[0008] In another embodiment, the obtained pressure signature from a blade passage is compared to an average signature of the entirety of blade passages from a given blade row at a given point of time. Any variations in the comparison are identified to indicate a fault in a rotating blade.
[0009] In yet another embodiment, the present invention may be used to detect the mechanical spallation of thermal barrier coatings (TBC's) integrity of the rotating blades of a rotor in a gas turbine.
[0010] In a further embodiment, the present invention may be used to monitor periodic aerodynamic phenomena, such as for example, the occurrence of rotating stall on start-up of axial compressors.
[0011] In one aspect, the present invention provides a non-intrusive method of monitoring the integrity of a rotating member, comprising mounting at least one sensor in a stationary frame of reference in a casing over the rotating member; measuring a pressure field generated by the rotating member; comparing the measured pressure field with a reference value; identifying variations in the comparison step, the variations indicative of a fault in the rotating member; and generating an output indicative of an identified fault. The method further includes performing phase averaging of measured pressure fields to remove interference signal content, storing in real-time the measured pressure field data in a memory system; and freezing the memory system to protect the integrity of the stored data in the event of a failure.
[0012] In another aspect, in a compressor having a plurality of rotating blades, a method of monitoring the integrity of the rotating blades comprising disposing at least one sensor about the rotating blades to measure a pressure field of a rotating blade; comparing the measured pressure field with corresponding reference value to identify variations in the measured pressure field; and generating an output indicative of variations in the measured pressure field.
[0013] In yet another aspect, the present invention provides a non-intrusive method of monitoring the integrity of a rotating member of a gas turbine of the type having a compressor with a plurality of rotating members, a generator, and a turbine, according to various embodiments of the invention.
[0014] In a further aspect, an apparatus for monitoring the integrity of rotating components of a gas turbine, comprising at least one sensor operatively coupled to the compressor to measure the pressure fields of rotating components; a processor system operatively coupled to the at least one sensor for performing phase averaging of the measured pressure fields; and a comparator operatively coupled to the processor system for comparing the measured pressure field data with a reference value. The apparatus further comprises a user interface coupled to the comparator for identifying a faulty rotating component in the event of a deviation in the measured pressure field of the rotating component from the reference value. The sensor is preferably a dynamic pressure sensor or a hot wire anemometer.
[0015] In another apsect, a non-intrusive apparatus for monitoring the integrity of a rotating member, comprising: means for measuring the pressure fields of the rotating member; means for comparing the measured pressure fields with a reference value to identify a fault in the rotating member; and means for generating an output indicative of the identified fault. The apparatus further comprises means for performing phase averaging of measured fields to remove random signal content.
[0016] In yet another aspect, a non-intrusive apparatus for monitoring the mechanical integrity of a rotating member of a compressor, comprising at least one sensor operatively coupled to the compressor for measuring compressor parameters; a comparator operatively coupled to the at least one sensor for comparing the measured compressor parameters to corresponding reference values to identify a faulty rotating member; and a user interface coupled to a processor system for displaying an identified fault.
[0017] In a further aspect, a non-intrusive method of monitoring the integrity of a rotating member among a plurality of rotating members, comprising mounting at least one sensor in a stationary frame of reference in a casing over the rotating members; measuring the pressure fields of each of the rotating members of a blade row; performing an average of the measured pressure field; comparing the measured pressure field of a rotating member with the average pressure field; identifying a faulty rotating member in the event of a mismatch in the comparison step; and generating an output indicative of an identified fault.
[0018] The benefits of the present invention will become apparent to those skilled in the art from the following detailed description, wherein only the preferred embodiment of the invention is shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] [0019]FIG. 1 illustrates a high level block diagram of the present invention;
[0020] [0020]FIG. 2 shows pressure data acquisition system of the present invention;
[0021] [0021]FIG. 3 illustrates an exemplary contour plot for absolute wall static pressure in three blade-to-blade passages of a given blade row in accordance witht the present invention;
[0022] [0022]FIG. 4 illustrates a graph showing some of the data collected and synthesized to form a signature as shown in FIG. 3;
[0023] [0023]FIG. 5 illustrates a method of collecting pressure data by the data acquisition sub-system of the present invention;
[0024] [0024]FIG. 6 illustrates a method of averaging collected pressure data as shown in FIG. 4;
[0025] [0025]FIG. 7 illustrates a waveform resulting from phase averaging the waveform shown in FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring to FIG. 1, there is shown a high level block diagram as indicated at 30 of the present apparatus for non-intrusively monitoring the integrity of rotating blades 42 (FIG. 2). Apparatus 30 includes data acquisition system 40 for collecting pressure data produced by rotating blades 42 . The data acquisition system 40 preferably includes sensors 41 (FIG. 2) for collecting compressor parameters. For convenience, the present invention will be described with respect to a single compressor of a gas turbine and data acquisition with respect to one row of blades is discussed. The pressure data collected by system 40 is averaged by system 50 to remove random variations in data due to interference. The averaged data from waveform averaging system 50 is received by waveform analysis system 60 wherein the averaged data is compared with reference data to locate a faulty rotating blade. The waveform analysis system 60 may be, for example, a comparator or the like. The processor system 50 may be, for example, a computer or a microprocessor system. Any deviations in the measured data are identified as being indicative of a fault in a rotating blade 42 (FIG. 2). A user is informed about a faulty blade via a user interface 70 such as, for example, a display device or the like.
[0027] [0027]FIG. 2 shows a data acquisition system of the present invention as illustrated in FIG. 1 wherein a few exemplary blades 42 are shown. It will be understood that several such blades are present in a blade row. Likewise, several such blade rows may exist in a single stage of a compressor. Pressure field data generated by rotating blades 42 and collected by sensors 41 is received in a signal conditioner of control computer 43 . Signals received by computer 43 are amplified and forwarded to an A/D converter 44 for converting analog signals to digital signals. Sensor 41 is preferably a pressure sensor, and several such sensors may be disposed in a continuous array in casing 47 of the compressor. The control computer 43 also controls such factors as gain, amplification, offset, and supply voltage to sensors 41 , appropriate selection of such factors being necessary for proper collection of pressure data. Wavetek™ generator 46 receives a signal from a gas turbine engine (not shown) and filters the received signal to produce a clean filtered signal prior to passing the filtered signal to A/D converter 44 . Once a single revolution of an blade is marked, a triggering event is received in the A/D converter 44 for initiating pressure data acquisition by sensors 41 .
[0028] Still referring to FIG. 2, pressure data collected by sensors 41 is processed in a waveform averaging system 50 by segmenting the data into several parcels (such as, for example, 128) corresponding to the time required for one complete revolution, and averaging those parcels, thus producing a contour. Alternatively, the data parcels may be processed, via a Fast Fourier Transform (FFT), prior to averaging by converting instantaneous low time-domain signals to instantaneous frequency-domain signals. The frequency-domain signals are then averaged to remove undesirable interferences. The A/D converter 44 may be operated by controller 45 .
[0029] [0029]FIG. 3 shows an exemplary contour plot for absolute wall static pressure for a healthy compressor produced by each of the rotating blades 42 of compressor 48 (FIG. 2). For the sake of brevity, only four blades 42 are shown. It will be understood that more than four blades may be present in a blade row. Sensors 41 are identified on the Y-axis and non-dimensional time is charted on the X-axis. In the exemplary embodiment, FIG. 3 depicts pressure contour plots of different blades within a single blade row wherein each rotating blade 42 is interrogated to monitor the differences in pressure contours indicative of the integrity of the blades 42 . The sensors 41 are preferably arranged axially across the blade passage. In the exemplary arrangement shown in FIG. 3, ten sensors are used. However, the number of sensor should not be construed to be limiting of the present invention. Pressure signatures are obtained by sensors 41 as the blade 42 passes beneath the sensors 41 . Each sensor 41 collects data over a particular circumferential “slice” of the blade passage. For example, the sensor over the leading edge slice is exposed to the leading edge of all of the blades in the blade row.
[0030] [0030]FIG. 4 shows some of the data that is collected and synthesized to form a signature as shown in FIG. 3. FIG. 4 depicts the passing of a number of individual blades beneath a plurality of sensors deployed across the blade-to-blade plane.
[0031] [0031]FIGS. 5 and 6 illustrate the collection and averaging of the pressure data collected by sensors 41 (FIG. 2). FIG. 7 shows a waveform with a fault identified in one of the rotating blades 42 . Pressure contour data measured by sensors 41 is processed in waveform analysis system 60 where the measured pressure contours are compared with reference contours to identify a faulty blade.
[0032] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it will be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. | A non-intrusive method of monitoring the integrity of a rotating member comprising mounting at least one sensor in a stationary frame of reference in a casing over the rotating member, measuring the pressure field of the rotating member, comparing the measured pressure field with a corresponding reference pressure field, identifying variations in the measured pressure field, the variations indicative of a fault in the rotating member, and generating an output indicative of an identified fault. | 5 |
RELATED APPLICATION
This application is a national phase application of PCT Application PCT/GB2004/001366, filed Mar. 31, 2004, and published in English on Oct. 14, 2004 as International Publication No. WO 2004/087826, which claims priority from British Application Nos. 0307504.1, filed Apr. 1, 2003, and 0325658.3, filed Nov. 4, 2003. These disclosures are hereby incorporated by reference herein in their entireties.
The present invention relates to a system and a method of improving the attaching or bonding of two or more surfaces together and a method of detaching or debonding them and an apparatus therefore. The method and apparatus of the invention is of particular, but not exclusive use, in the automotive, aeronautical, nautical, decorating, packaging and construction industries for adhesive bonding and debonding adhesive interfaces of panels, frames, films, joints, plates, glazing or any other such items which need to be bonded together and/or separated; in some instances the debonding system and method of the present invention may be applied to an adhesive. The present invention is also applicable to dentistry and surgery where it is desired to cement a dental filling or in bone joint replacement. The system of the present invention may also use the thermally expandable microspheres as a vehicle or transporter for other agents on their expanding shell surface and so aid in their dispersion within a matrix or other systems, including the cleaning industry or they may be used to disperse/mix multifunctional particles and/or nanoparticles so as to avoid clustering.
BACKGROUND TO THE INVENTION
It is known from the prior art to attach car body parts together, by for example, riveting or spot welding them together and more recently laser. A recent trend in the car industry is to use a modular construction for vehicles, whereby individual modules are connected/attached/bonded to form the main vehicle body and associated parts. Typically car door or body panels are welded and/or riveted together in order to achieve a tight attachment of the two parts. Welding uses intense heat to melt one or more of the interfaces of the parts and needs to be performed by specialists aware of the risks of intense heat, both to themselves and to car parts. The intense heat can cause the substrate surface to buckle or melt and great skill is required to ensure that only the sections/portions/spots needing to be welded actually receive the heat so as to minimise the potential for heat damage to other parts. In order to detach these riveted/welded parts strong mechanical strength is required.
It is also known in the prior art to use adhesive compositions to effect secure attachment of two surfaces/substrates of vehicle components. Adhesive compositions or glues have been widely used to secure windscreens to frames by applying the adhesive to one or both surfaces of the components and aligning them so that the surfaces are bonded/attached together. Typically the adhesive compositions contain curing agents in order to promote or accelerate the adhesive solidification process. The curing agents can be heat or moisture activated and are included in the composition so as to cross-link or polymerise the liquid adhesive into solid form and so accelerate the chemical bonding process. In order to detach the adhesive bonded component(s) thermo-mechanical strength can be applied to separate them. For example, in the instance of detaching a windscreen from a frame which has been firmly bonded in place as the adhesive sealant is hardened, typically involves the automotive glass fitter to remove the windscreen (usually in intact form) using a device comprising a cheese-wire or special knives to cut/saw through the hardened rubber along the periphery of the windscreen. This process requires strong physical force to separate structurally the cohesion strength of adhesive and can lead to musculo-skeletal conditions in the fitters themselves as a result of repetitive strain injury. Further problems associated with this method are that the cheese-wires can overheat due to friction, additionally the wires themselves can break. It is becoming routine in the automotive industry in an effort to minimise vehicle weight to improve performance and to reduce petrol consumption to employ adhesives to bond other car components such as door skins to frames, accordingly the use of adhesive compositions is becoming more widespread in this area of technology. In addition as the new End of Life Vehicle (ELV) Directive becomes implemented, there is a need for detachment or debonding of adhesives in the automotive industry so as to dismantle and recycle car parts such as bonded glazing, panels and so on in a quick, cost-effective, safe and if possible reusable way. Thus there is a need for improvements to debonding various surfaces.
Thermally expandable thermoplastic microspheres have been commercially produced for several years and have been used as fillers in polymers, paints, putty, plastisols, printing inks and as fillers in paper, paperboard and explosives. WO 95/24441 describes a substitute to polyurethane foams in the form of an adhesive composition for filling vehicle box parts and providing sound-proofing which includes 5-15% of expandable micro-spheres encapsulating alkanes. WO 00/75254 also describes adhesive and adhesive primer compositions comprising thermo-expandable microspheres, heat activation of the microcapsules creates a pressure along the interfaces of where the composition has been applied which reduces the surface adhesive bonding and shear or tear stress of the adhesive material. The reduction in chemical and/or physical bonding of the adhesion at the interface of the two bonded surfaces is due to the effect of the expanded microspheres so that they may be described as capable of de-bonding with no cohesive fracture when in their expanded state. The microspheres present at the interface change the structure of the bonding adhesive surface to create instant debonding when supplied with the appropriate trigger. The debonding surface energy is approximately one third lower than the cohesive fracture energy.
One of the problems associated with the automotive industry is that at the vehicle end of life (ELV) most of the vehicle components more than 85% have to be detached and removed from the vehicle so that they can be safely disposed of or recycled in separate and dedicated processes. The disposal of vehicles at the end of life can be time consuming, hazardous to health and the environment and expensive as interior items, dashboards, panels, door skins, plates, frames, light units and other such components need to be detached from one another.
A method and apparatus to carry out a method which would enable rapid, ideally in a matter of minutes, non-toxic material degradation in an efficient manner and safe detachment of such components would offer immediate advantage to the prior art, not only in the automotive industry but in any field where it is desired to detach two surfaces/substrates that have been adhered (bonded together) by means of an adhesive bonding system that can be present in either an adhesive and/or primer and/or cleaner component of the system.
It is envisaged that the method of the present invention may be used in many diverse areas where microspheres are used, for example and without limitation, in cleaning and hygiene, dentistry, surgical medicine, sports equipment manufacture, furniture and finishings especially decorative wallpaper and other situations where it is desired to detach more than one surface. The increased volume of expanded microspheres may also be used to aid transport and dispersion of agents deposited on their surface so mitigating the problem of clustering and agents responsible for clustering a phenomenon associated with decreased functional activity.
STATEMENT OF THE INVENTION
Various aspects of the present invention will now be described in more detail with respect to other embodiments described herein. It should be appreciated that the invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items.
Unless otherwise defined, all 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 belongs. All publications, U.S. patent applications, U.S. patents and other references cited herein are incorporated by reference in their entireties with respect to the text referenced by the citation.
According to a first aspect of the invention there is provided a method of debonding two or more surfaces or supports or layers of an adhesive system, the adhesive system comprising an adhesive composition at its bonded surface(s), the composition being placed between said surfaces or supports or layers, and the adhesive composition comprising an adhesive agent and/or a primer and/or a cleaner at its interface and dispersed therein thermoexpandable microspheres, in order to debond the system a sufficient power level of thermal radiation and/or thermal energy is provided which concentrates on the adhesive surfaces so as to expand the microspheres in the adhesive and/or a primer and/or a cleaner layers and so causes weakening of adhesive surface forces at the interface of said layers in the adhesive system.
Preferably, the weakening of the adhesive forces at the interface of said layers does not cause cohesive fracture or degradation of the matrix, especially toxic degradation of the matrix.
Preferably, the method further includes the step of curing the adhesive composition prior to debonding by providing a power level of thermal radiation and/or thermal conduction and/or thermal energy which passes through the adhesive composition so the contents of the expanded microspheres leach or migrate through their porous shells into the matrix of the composition.
Preferably, the microspheres used in curing are uniformly distributed in the adhesive matrix.
The present invention differs from the prior art in that the adhesive system comprising thermoexpandable microspheres at the cleaner and/or primer interface is not directly heated rather the microspheres themselves receive energy in the form of thermal radiation from an IR or UV source or electrical source and/or thermal conduction from the surface of the item which is to be bonded. We have found surprisingly that it is not necessary to heat the entire adhesive system/composition as microspheres appear to preferentially absorb thermal radiation from IR and that certain microspheres are able to expand at a lower temperature than that of the composition. We have found that certain microspheres when exposed to IR energy expand at approximately 40° C. less than the adhesive in which they are mixed. In this way we have unexpectedly found it is not necessary to heat the adhesive composition in order to expand the microspheres but rather to heat the microspheres themselves. Accordingly this provides the additional advantage of minimising energy consumption and reducing the risk of damage to the bonded substrates.
Reference herein to an adhesive system is intended to include an adhesive composition comprising at least one adhesive agent with or without a primer and/or cleaner or curing agent or solvent or any other material which is included to effect adhesion of one or more surfaces together either as layers or sandwiches. The adhesive composition embeds or supports the microspheres and in the instance of the adhesive layer being comparable with the size of the microspheres both sides of the adhesive layer can be affected by the microspheres and triggered from both sides.
Reference herein to a cleaner and/or primer is intended to include any surface treatment to promote the adhesion of adhesives and/or sealants.
The present invention provides a method and apparatus for debonding an adhesive system wherein the system comprises thermoexpandable microspheres dispersed in an adhesive composition the composition being placed between two or more surfaces of the system and optionally a method of curing the same composition.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
According to a second aspect of the invention there is provided an adhesive system comprising curing an adhesive composition and/or de-bonding the same adhesive composition at its bonded surface, the composition being placed between two or more surfaces of supports or layers, and the adhesive composition comprising an adhesive and/or a primer and/or a cleaner at its interface and dispersed therein thermo-expandable microspheres the system comprising the steps of:
(i) activating a method of curing the composition by providing a first power level of thermal radiation and/or thermal conduction and/or thermal energy which passes through the adhesive composition so the contents of the expanded microspheres leach or migrate through their porous shells into the matrix of the composition; and
(ii) de-bonding adhesive interfaces of the same surfaces of supports or layers by providing a second power level of thermal radiation and/or thermal energy which concentrates on the adhesive surfaces so as to expand the microspheres in the adhesive and/or a primer and/or a cleaner layers and so causes weakening of adhesive surface forces at the interface of said layers in the adhesive system.
Preferably, in the curing step the microspheres release their contents uniformly into the adhesive matrix.
The method of the present invention thus may comprises two distinct phases or stages which not only are controllable but in practice are performed at two different time points. It will also be appreciated that the adhesive system may use each of the distinct phases in isolation, that is to say it may only be used to debond an adhesive system according to the first aspect of the invention or the may be performed with the same adhesive composition so as to cure and debond the same system as in the second aspect of the invention.
The curing phase occurs subsequent or immediately after deposition of the adhesive composition and the debonding phase typically may be performed days, weeks, months or years apart from the curing phase. With this in mind it is important that the microspheres used for curing are able to lay dormant, that is to say do not leach their contents into the composition matrix or in the stock before application; the debonding phase occurs in the cleaner and/or primer interfacing but not until the microspheres are triggered so by application of thermal energy instigated on command by a user.
The first phase or stage is curing; Curing is generated by a first species of thermally expandable microspheres dispersed in the adhesive bead matrix. This first species encapsulates within their plastic or copolymer shell a blowing agent and curing agent preferably mixed together and they may optionally further include a catalyst or activator. The curing agent disperses in the adhesive matrix when sufficient thermal radiation and/or thermal conduction and/or thermal energy and/or electrical energy is supplied to this first microsphere species so as to cause their thermal expansion and allow their contents to leach or migrate or pass or be transferred or released through or across the porosity of the expanded shell. The contents of this first species of thermally expandable microspheres is released into the adhesive matrix at a certain specified temperature which is typically lower than that of the second species of thermally expandable microspheres which are employed to effect interface debonding. The second species of microspheres, i.e. those which are activated at an different and typically elevated temperature to those of the first species are preferably provided substantially as a blend in the cleaner and/or primer interfacing of adhesive compositions to facilitate separation of the surfaces. Alternatively, the microspheres used in debonding can be provided as a blend in the adhesive itself, especially in adhesive systems requiring a low thickness or thin layer of adhesive composition comparable with the size of the microsphere in this way the microspheres may be triggered from both interfaces of the layer.
It will be appreciated that the microspheres may be present dispersed throughout an adhesive composition or they may be present in a primer or cleaning layer or in a paint layer so that when thermal energy is supplied to expand the microspheres they change the surface structure of the material in which they are dispersed so as to create an instant debonding effect.
The present invention resides in providing energy in the form of radiation and/or thermal conduction and/or electrical heating to the microspheres of either or both phases of the method of the first and second aspect of the invention. The thermal conduction and electrical heating to the microspheres for debonding is provided via contact with the surface of the substrate or by electrical current or heat passing through the adhesive composition or system. It will be appreciated that microwaves or supersonic waves may also be employed as a thermal source.
In the present specification, bonding refers to the physico-chemical process of adhesion during the curing process and particularly this bonding in the present specification is additionally increased by creating an increased rough or uneven surface on the area of interface especially by the thermoexpandable microspheres of the debonding microspheres in their initial state mixed in the cleaner and/or primer. Accordingly, the present invention advantageously is able to not only increase the speed of curing but also to strengthen the adhesive properties of the composition at interfaces.
The debonding microspheres are suspended in the composition positioned or floating on the uppermost surface and with a suitable size they purposefully create a rough or uneven increased surface area and thus provide higher mechanical and stress strength as compared to an adhesive without microspheres.
Debonding refers to the physical breaking of the chemical formulation in the adhesive system and breaking of the chemical bonding forces at interfacings.
Expansion of the microspheres at the interface surface increases their volume so that the microspheres fill the entire surface space and substantially fill or occupy the whole interface surface, thus allowing for the breaking of bonding forces at the interface or interface layers.
In the present specification, the curing process refers to a process separate and distinct from the bonding and debonding process hereinbefore described. The purpose of the curing process is mainly to impart mechanical structural strength to the adhesive composition and chemical bonding at an interface, it does not effect the volume of the adhesive bead rather it effects the mechanical behaviour of the bead and the chemical bonding at the interface.
Preferably, inside the encapsulating shell of the first species of microspheres used for curing, the curing activator may be mixed with blowing liquid and optionally a catalyst so that when activated by thermal energy the contents pass through the porous shell of the expanded microspheres supported by the leaching of expanding gas. In the case of an activator from the leaching of the blowing agent, their action of curing is distinguished from the process following uniform distribution in the adhesive matrix. This may be achieved by UV radiation in the case of activators that are photo-radicals or photo-ions, accordingly in this instance the activator leaching aids the uniformity of mix within the matrix.
Preferably, the expanding agent is selected from the group comprising an expandable gas, a volatile agent, a sublimation agent, water, an agent which concentrates water or an explosive agent.
Preferably, the adhesive is polyurethane or polyvinylchloride or an MS polymer or an epoxy resin or any other suitable adhesive in which microspheres may be dispersed and which it is desired to strengthen or cure more rapidly. Thus, when the microspheres are used in dental situations the adhesive is a dental filling mixture and when used in surgical situations may be of a bone type cement.
Preferably the microspheres encapsulating the curing agent of the first species of microspheres are activated at a different temperature compared to that of the second species, preferably the first species activation temperature is lower that of the second species and the temperature difference is between 20 to 100° C.
Preferably, the debonding or second species of microspheres are activated in a temperature range of about 30 to 250° C. and more preferably at about 110 to 200° C. Preferably the second set of microspheres encapulate an expanding agent and are of smaller cross sectional diameter than the first species of microspheres.
It will be appreciated that in the first aspect of the invention only the second species of microspheres are required and optionally may include the first species whereas in the second aspect of the invention the adhesive system comprises both species of microspheres.
In one embodiment of the invention where the microspheres are used in the cleaning industry and especially as washing powder dispersing aids the temperature activation will be in the lower end of the range, probably in the region of 30 to 80° C., a temperature compatible with domestic hot water.
In another embodiment of the invention where the microspheres are used in dental fillings the temperature activation range is in the region of 40 to 70° C., a temperature compatible with oral conditions.
From the foregoing it will be appreciated that the temperature activation range is dependent on a users requirements and as such the temperature activation of the microspheres is not intended to limit the scope of the application since it is the methodology of debonding at an interface which is the essence of the invention and optionally curing beforehand.
The shell of the microsphere is typically made of a copolymer acrylic and PMMA mix which has hitherto prevented their possible use below around 80° C. We propose to adapt the composition of the shell by including plastics such as polypropylene, PVC and/or polyethylene in this way the microspheres may expand and much lower temperatures and so find use with the method of the present invention in dental, medical and cleaning (washing powder) situations.
It will be appreciated that when using microspheres for both curing the adhesive and bonding/de-bonding microspheres at interfaces a sufficient temperature difference is required so that the two processes may be achieved without overlap and thus distinct temperature ranges are preferred. It will also be appreciated that the composition may also comprise thermoexpandable microspheres encapsulating more that one different or combinations of agent and that each set or species of microspheres may differentially be expanded when exposed to suitable temperatures so that the composition may go through a set of defined processes according to the applied temperature which can be specified. Accordingly the method of the present invention is equally applicable to sticking and un-sticking, for example, wallpaper which will require a low thermal activation or it may be used to bond and de-bond vehicle parts which will require relatively higher thermal activation.
Preferably, the ratio of the proportion of the first species of microspheres encapsulating the curing or other agent to those of the second species encapsulating the debonding agent will be variable and it will be appreciated that the proportion may be selected according to a user's requirements or for the particular application in mind and thus should not limit the scope of the application.
Preferably, the second species of microspheres may be coated in a suitable black or dark material to increase optical density and thus prevent UV light penetration to degrade the adhesive, in this embodiment the “trigger” would be an IR or electrically generated thermal source. In one example when the method and composition is for use with vehicle glazing, the frit can be coated with microspheres coated with a dark material with a purpose to further reduce penetration of UV light and to reduce degradation of the adhesive.
It will be appreciated that by coating the microspheres with a black material this acts to reduce the optical density of the frit on the windscreen or, if desired, stereographical printing. We have found that it is necessary to coat the microsphere in the appropriate material as the coating affects their porosity. Thus when the microspheres expand, the porosity of the frit is affected and in practice, this creates a barrier to the UV. The expandable microspheres by virtue of the porosity of their spherical shell surface may be used advantageously to disperse nanoparticles and hence prevent or minimise clustering during mixing of a dispersion composition which includes a curing plastic and a solvent. In this way, following evaporation of the solvent the microspheres may act as a dispersant to avoid nanoparticle clusterization.
In this embodiment of the invention, that is to say coating of the shell of the microspheres with additional agents, the unexpanded microspheres may be coated with agents depending on the user's requirements. For example the unexpanded microspheres may be coated with, for example and without limitation:
a monomer to be catalysed by UV radiation or other energies for improved adhesion in a polymer matrix nanoparticles to improve their distribution and/or their dispersment. molecules which create barriers to, for example, electromagnetic waves, chemicals, O 2 degradation in the food packaging industry so preventing premature spoiling, acoustic and sound waves, thermal or any other function for which it is desired to create a barrier.
These functions operate on the expanded surface which can realise up to 10 m 2 for only 1 gram of microspheres present in the matrix. It is believed that the present invention may be used to improve the dispersment of, for example and without limitation, scent, fragrances and/or cleaning agents into a solvent such as water. It may also be used to improve the delivery of pharmaceuticals and other such agents. It may also be used as a barrier to prevent clustering of nanoparticles and such like. In addition nano-scavangers maybe used as a barrier to the atmosphere and so prevent food deterioration inside packaging film or paper boxes/cartons.
In one embodiment of the invention, the shell of the microspheres can be coated with suitable molecules on their surface or they may encapsulate them so that the microspheres act as a “vehicle” or “transporter” to enhance the effect of the carried molecule, and in so doing the microspheres may improve efficiency and dispersion of the carried molecules. It is envisaged that the microspheres may, in this embodiment, be used following the principles as set forth:
the microspheres may be used as a vehicle for dispersing a carried molecule on its coating or which it encapsulates to a larger molecule. the microspheres may act as a chemical or physical barrier. the microspheres prepare molecules to be evenly, easily and more readily dispersed. the microspheres can act as a support where photocatalysis is efficient as the molecule acts as a very thin film on the expanded microsphere surface.
In summary, the shell of the microspheres can be coated with or encapsulate various materials making them multifunctional and useful for addressing many problems and of use in many different areas. As previously stated the microspheres can be coated with or encapsulate either a monomer and/or nanoparticles or a detergent or gold and these entities can be distributed on the surface of the microspheres in their unexpanded state and be multifunctional. We have utilised the change in volume of the microspheres so that their surface becomes up to ten times more than their initial surface so one can achieve, from a single gram of microsphere in the matrix about 0.5 m 2 and if we use microspheres of a different expansion capacity for example of up to 100 times the volume expanding we can achieve between 6 to 10 m 2 of surface. In such an embodiment, the microspheres can be used to disperse the parts of the materials i.e. monomer and/or nanoparticles that are on their surface. In practice, we have found that clustering can be avoided when the unexpanded or initial microsphere shell is loaded with nanoparticles of 20 nm diameter, in the expanded state where the nanoparticles remain on the shell surface 76% distribution was achieved.
In this sense the microspheres act as a vehicle to make the coated particles ready to be dispersed in the salvage state in order to reduce the time of their dispersion and obtain a uniform distribution on the expanded microsphere surface. Accordingly it is possible to achieve a surface that will attain the same longevity with the same particles because the shell reduces thickness but the materials that are on the surface of the expanded microspheres remain the same.
The microspheres may also be used according to a second critical observation in that they tend to become a barrier for electromagnetic radiation and also a barrier to acoustic waves passing through such a matrix containing them. They may also be a barrier to atmospheric degradation in the food packaging industry.
The microspheres may also be used to prevent clustering, that is to say clumping together of molecules a problem associated with the cleaning industry.
Preferably, the thermal radiation and/or thermal conduction or electrical energy provided to the microspheres is provided from a means comprising a source of electromagnetic waves such as IR or UV radiation, or from a convection oven or from electrical means such as a battery or a laser or from an ultrasonic source or from gas or air or from white light.
In the instance of using the adhesive system as a backing in decorative paper the debonding can be effected by for instance a domestic iron or hair dryer.
As will be appreciated IR is an electromagnetic wave which only becomes thermal when it is absorbed by a body with certain properties onto which the IR is directed. Thus a system employing IR only becomes a “thermal” system when the IR beam is absorbed by the body. Accordingly IR radiation becomes a heating source by changing the IR electromagnetic waves of 800-2600 nm up to thermal radiation 3000-7000 nm and thermal conduction. In the present invention the thermoexpandable microspheres are principally heated by IR or UV and/or thermal radiation and not thermal conduction from for example a metal panel.
In the instance of using IR radiation spectrum as the energy source, it will be provided in the form of one or more lamps or in the form of optical fibres or optical rods or plates. IR radiation will be transformed to thermal radiation of the internal surface, of for example a panel, on the heating side which strongly depends on the temperature achieved by the panel exposed surface. The power thermal radiation depends on the T exp 4 of the surface panels which is not within the low range of IR radiation as the lamp, but with thermal IR radiation of about 3000-7000 nm. It will be appreciated that heating by conduction depends on many parameters such as the thermal conductivity of the material of the surfaces or panels, the cleaner-primer and the composition of adhesives layer.
In the instance of using an electrical heating as the heating source to expand the microspheres, the electrical heating can be generated by electrical current passing through a panel which becomes a resistor. In one embodiment of the invention, aluminium or steel wires/filaments/strands or micro-wires or carbon microfibres or other electrically conductive fibres such as metal coated glass fibres are embedded in the adhesive composition especially at the adhesive interface so as to create a Faraday cage. The micro-wires are dispersed in the adhesive to create a tangle or polygonal arrangement of electrical conductors. This tangle allows a great number of small electrical rings to be formed in three dimensions all around the expandable microspheres which can be caused to expand at a certain maximum temperature. This phenomenon is referred to as tunnelling for electrical current.
Preferably, the micro-wire or fibres are mixed with the adhesive and may be around 100 μm in length and between 2-20 μm in diameter. In one example, carbon fibres could be 5-10 μm in diameter and 50-100 μm in length. We believe that in order to effect tunnelling the composition should ideally comprise about 0.5-10% volume of the micro-wires and more preferably about 1-3% volume. It will be appreciated that the volume % of microspheres within the composition affects the number of contacts bridging one with another and that this may be selected according to a user's requirements.
Preferably, the thermoexpandable microspheres may be provided embedded or coated on to a tape or mesh or film or may be provided attached to a wire or filament or fibre alternatively they may be attached to a contact surface of one or both component which it is desired to cure and/or separate. The first species of microspheres may be
Preferably, the released curing or activating agent is uniformly distributed in the adhesive matrix so that they may be activated with their own energy system such as polymerisation and/or cross-linking or UV activation of photo-radicals and/or photo-ions.
Accordingly the present invention provides a unique approach to prior art methods of plastic-plastic, plastic-metal, metal-metal, ceramic-metal, aluminum-aluminium, aluminium-plastic, composite-metal, composite-plastic, composite-ceramic, paper-wall, dental-filling-tooth, artificial joint-bone and the like surface attachments since the composition is not directly targeted by for example an IR or UV beam transparent to one of the sandwich panel but rather the composition is heated by thermal radiation and/or thermal conduction of the contact surface or its under-surface.
Preferably, the method includes any one or more of the features hereinbefore described.
In particular we have found by experimentation, investigating parameters of the IR lamp such as reflection, power and optical spectrum of the ray's beam, that in order for IR to be absorbed by the blowing agent and its mixture it has to be adapted for expanding the microsphere at a temperature before the degradation of the matrix embedding the microsphere or before the degradation of the adhesive system, where the microspheres are embedded in the primer and/or cleaner interface. In this way, toxic agents, due to the degradation of the adhesive may advantageously be avoided even with PU adhesives.
According to a further aspect of the invention there is provided a method of detaching two surfaces that have been bonded together comprising, supplying sufficient thermal radiation and/or thermal conduction to a surface having coated thereon or attached thereto the composition as hereinbefore described, the thermal energy being supplied to one or both contact surfaces of each item which are to be detached/separated so as to cause a proportion of the thermoexpandable microspheres to release an expanding agent into the composition.
Preferably, the method includes any one or more of the features hereinbefore described.
It will be apparent that in the present invention, chemical interactions are avoided and that the method of the present invention relies on physical engineering technology to permit and facilitate a curing system which needs to mix the curing activator by a uniform distribution at certain time at command in the adhesive bonding stage process and advantageously may also differentiate zones where the thermoexpandable microspheres can be suitably mixed. In principle the thermoexpandable microspheres act as microscopic containers of the curing activators which are neutral or inert up to a certain moment when they break or increase their volume in such a way to initiate their shell as a porous wall to leach the activator, in gas or liquid state, so that it can diffuse uniformly in to the adhesive matrix transport by the gas of blowing agent.
Activation of different activators is possible by the differentiation of temperature activation for the thermoexpandable microspheres, in this way it is possible to effect curing of the adhesive composition at different stages in the process at different areas and moreover at applied and specific commands making the overall process more controllable and with multifunctional performances.
The present invention advantageously provides a curing process that is controllable in that it is not dependent on a chemical reaction such as polymerisation, cross-linking, crystallisation, gelification or any other phase transitions.
According to a yet further aspect of the invention there is provided an apparatus for attaching or detaching two surfaces that have been bonded together comprising an IR emitting device comprising at least one bulb, at least one lens to concentrate the beam at certain area and at least one reflecting mirror mutually arranged so that heat is directed or focused only at an adhesive interface or an adhesive interface with a cleaner and/or primer or a path where the thermoexpandable microspheres are purposely present.
In one embodiment of the invention the IR emitting device is in the form of one or more lamps and typically is in the form of a group or plurality of lamps.
Preferably, the IR device emits IR radiation in the range of about 800-1400 nm to 2000-6000 nm.
Preferably, the device is automated and may be linked to a computer programme providing information to device sensors of an adhesive bonding-path.
Preferably, the device is mounted on a mobile unit so that it is free to follow a predefined adhesive bonding path.
The arrangement of the device of the present invention allows the IR beam to be concentrated only at certain partial points of the surface which it is desired to bond or de-bond.
Preferably, lenses with parallel shape of the adhesive-thermoexpandable microsphere, bonded paths can be used with standard IR lamps where the beam can be concentrated in a special area. In this heating concept the IR optical fibre or optical tubes, even with the laser source, can be used as a flexible or rigid heating tool producing strong and rapid power by rapidly moving along the bonded area with special designed drawings of adhesive parts.
Preferably, the device may be pre-programmed to follow a specific bonding path.
According to a yet further aspect of the invention there is provided a method of de-bonding an adhesive composition, the composition being present at an interface and being placed between two or more surfaces of vehicle glazing or vehicle panel(s) or part(s) the composition comprising an adhesive or cleaner and/or primer and thermoexpandable microspheres dispersed therein the microspheres having a diameter of between 10-50 μm and an activation temperature range of between 110-210° C. and encapsulating at least one blowing agent the debonding being effected by exposing the microspheres power level of thermal radiation and/or thermal energy that results in a temperature received by the microspheres in the range of 110-210° C.
Preferably, the method further includes the step of curing the adhesive composition prior to debonding by providing microspheres 30-50 μm and an activation temperature range of between 50-100° C. the microspheres encapsulating a curing agent and/or catalyst and/or activator and effecting curing by exposing the microspheres power level of thermal radiation and/or thermal energy that results in a temperature received by the microspheres in the range of 50-100° C.
According to a yet further aspect of the invention there is provided a method of curing an adhesive and de-bonding the same adhesive from automotive glazing or panels or parts comprising applying a composition comprising an adhesive and thermoexpandable microspheres dispersed therein, a first set of microspheres having a diameter of between 30-50 μm and an activation temperature range of between 50-100° C. and a second set of microspheres having a diameter of between 10-50 μm and an activation temperature range of between 110-210° C. the second set of microspheres being present at an interface of the adhesive or cleaner and/or primer, the composition being placed between two or more surfaces of the glazing or panel or part(s) and:
(i) activating curing of the composition by exposing it to a first power level of thermal radiation and/or thermal energy that results in a temperature received by the microspheres in the range of 50-100° C.; and
(ii) de-bonding the adhesive system at its interfaces by exposing it to a first power level of thermal radiation and/or thermal energy that results in a temperature received by the microspheres in the range of 110-210° C.
As mentioned herein before the steps of curing and debonding may be performed in isolation with the same composition or may be debonded with or without a curing phase, the requirement for a curing step is not intended to limit the scope of the application.
The system in step (i) activates curing of the adhesive composition, by exposing them to a first level power of thermal radiation and/or thermal conduction or a thermal energy. This thermal energy passes through the adhesive system to the microspheres; so the contents of the expanded microspheres leach or migrate through the porosity of the microspheres shell. The shell thickness is reduced due to its expanded state. Its contents leaches or migrate into the matrix of the adhesive composition thus releasing a curing agent or catalyst or activator, into the matrix. This process occurs subsequent to adhesive deposition on the glass or plates.
The system in step (ii) debonds adhesive interfaces of the same glazing or panel or part treated with the method (i), by exposing them to a second power level of thermal radiation and/or thermal conduction and thermal electrical energy. This second power level activates the microspheres so they expand and so weaken and/or debond the surface adhesive system forces at temperature advantageously lower than the degrading temperature of the adhesive system composition.
It will be appreciated that step (i) may occur just after the bead adhesive deposition and trigger the microspheres expansion to generate the leaching of the blowing glass containing the catalysts of the adhesive matrix to a curing process; step (ii) may occur after 10 to 15 years. This second step may be trigger the dormant microspheres by exposing the adhesive surfaces to a second power level energy by IR or electrical systems generating thermal energy.
The present invention provides an elegant method for curing and debonding of the same adhesive. Bach stage being a discrete operation that may be performed up to 10 years or more apart since the microspheres are able to lay dormant in the composition until triggered at command by an appropriate stimulus for example IR or electrically generated thermal energy.
The invention will now be described by way of example only with reference to the following Figures wherein:
FIG. 1A shows an electron microscope picture of an upper surface of an interface to be bonded;
FIG. 1B shows an electron microscope picture of a tangle of micro-wires and thermoexpandable microspheres;
FIG. 1C shows a higher power view of FIG. 1B and a micro-wires;
FIG. 1D shows an alternative view of FIG. 1C and a micro-wire;
FIG. 2 shows a schematic plan view of a microcapsule and film arrangement; and
FIG. 3 shows a front perspective view of a vehicle doorframe and skin with a conductive pathway in situ.
FIG. 4 shows a plurality of possible interfaces in the adhesive system of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1A there is shown an electron microscope picture of the surface of a primer adhesive interface coated with the composition and microspheres according to the present invention; Microspheres 1 can be seen projecting above the surface thus providing an uneven or rough surface. There are gaps between the microspheres. However these gaps or voids are filled once the microspheres have been expanded so that the surface will become more even and thus be able to be debonded. In FIG. 1B there is shown an electron microscope picture of a tangle of micro-wires and inter-dispersed microspheres are also visible. As described earlier aluminium or steel wires/filaments/strands, carbon microfibres, metal coated glass fibres or micro-wires are embedded in the adhesive composition especially at the adhesive interface so as to create a Faraday cage. The micro-wires are dispersed in the adhesive to create a tangle of electrical conductors. This tangle allows a great number of small electrical rings to be formed in three dimensions all around the microspheres which can be caused to expand at a maximum temperature. FIGS. 1C and 1D are electron microscope figures at higher powers of magnification.
In one embodiment of the invention, the microspheres ( 1 ) and micro-wires ( 2 ) can be attached to a continuous conductive filament or film or wire or fibre ( 4 ). Energy is supplied to the conductive filament ( 2 ) from an energy source ( 3 ), the energy source may be provided in the form of thermal energy or electrical power and transmitted to the microcapsules by thermal radiation and/or thermal conduction. Thus the microcapsule do not receive energy directly from the energy source but rather via the panel or component surface which is to be bonded, for example the microspheres may be heated by thermal radiation and/or thermal conduction of the panel, directly targeted by an IR radiation lamp focused on the open/exposed surface. In a yet further embodiment of the invention microcapsules ( 1 ) may be coated on to a mesh or bundle of conductive filaments/wires/fires or coated on to a tape or woven material. The microspheres ( 1 ) may be provided in a prearranged form or may be sprayed or painted on shortly before use. Once sufficient thermal radiation and/or conduction is imparted to the microspheres they may be activated at a selected temperature so as to accelerate and/or effect attachment in the initial state and debond in the expanded state. In the second phase with microspheres containing a blowing agent mixed with a curing activator in the instance of two surfaces having already according to the present invention. Microspheres 1 can be seen projecting above the surface thus providing an uneven or rough surface. There are gaps between the microspheres. However these gaps or voids are filled once the microspheres have been expanded so that the surface will become more even and thus be able to be debonded. In FIG. 1B there is shown an electron microscope picture of a tangle of micro-wires and inter-dispersed microspheres are also visible. As described earlier aluminium or steel wires/filaments/strands, carbon microfibres, metal coated glass fibres or micro-wires are embedded in the adhesive composition especially at the adhesive interface so as to create a Faraday cage. The micro-wires are dispersed in the adhesive to create a tangle of electrical conductors. This tangle allows a great number of small electrical rings to be formed in three dimensions all around the microspheres which can be caused to expand at a maximum temperature. FIGS. 1C and 1D are electron microscope figures at higher powers of magnification.
In one embodiment of the invention, the microspheres ( 1 ) and micro-wires ( 2 ) can be attached to a continuous conductive filament or film or wire or fibre ( 4 ). Energy is supplied to the conductive filament ( 2 ) from an energy source ( 3 ), the energy source may be provided in the form of thermal energy or electrical power and transmitted to the microcapsules by thermal radiation and/or thermal conduction. Thus the microcapsule do not receive energy directly from the energy source but rather via the panel or component surface which is to be bonded, for example the microspheres may be heated by thermal radiation and/or thermal conduction of the panel, directly targeted by an IR radiation lamp focused on the open/exposed surface. In a yet further embodiment of the invention microcapsules ( 1 ) may be coated on to a mesh or bundle of conductive filaments/wires/fires or coated on to a tape or woven material. The microspheres ( 1 ) may be provided in a prearranged form or may be sprayed or painted on shortly before use. Once sufficient thermal radiation and/or conduction is imparted to the microspheres they may be activated at a selected temperature so as to accelerate and/or effect attachment in the initial state and debond in the expanded state. In the second phase with microspheres containing a blowing agent mixed with a curing activator in the instance of two surfaces having already been attached together by an adhesive may be made to expand and release their contents at a different selected temperature and release an expanding agent such as a gas, an agent capable of sublimation, water, an explosive agent containing an activator agent. The resultant expansion causes a de-bonding or a faster bonding of the two attached surfaces.
In the instance of attaching a vehicle door skin (B) to a frame (A) as in FIG. 3 , the microspheres may be provided in pre-defined paths along the perimeter of the article which it is desired to attach. Path ( 5 ) may be in the form of a channel or groove into which the adhesive composition may be poured/sprayed or the microspheres may be provided already attached in the form of a mesh or tape or strip which can be appropriately positioned on either or both of the skin (B) or frame (A). The door frame (A) and/or skin (B) is provided with a plurality of conductive attachment means ( 6 ) and ( 7 ) respectively which can be connected to an energy source. Once the energy source is activated and the microspheres receive sufficient thermal radiation and/or conduction for example from an IR lamp of the present invention, they may expand and release their contents to effect attachment at a selected temperature or to cause de-bonding at a different selected temperature. In this way and conveniently, adhesion of two surfaces and separation of same may be achieved without recourse to chemical or physical processes using the same system and apparatus. Moreover and advantageously the system is controllable since the microspheres in the adhesive system will be selected according to the user's requirements of curing and bonding and debonding methods.
With reference to FIG. 4 there is shown a representation of a plurality of different interfaces which are to be included within scope of the method of the present invention. For example the vehicle glass ( 11 ) to cleaner and/or primer ( 10 ), cleaner and/or primer ( 10 ) to adhesive ( 12 ), adhesive ( 12 ) to primer or paint ( 13 ) and primer or paint ( 13 ) to the metal part or similar ( 8 ).
It will be appreciated that the invention has wide application to may different fields of technology where it is required to attach and detach two surfaces together for example and without limitations surfaces such as plastics, metal, ceramic, fibreglass and/or composites thereof, and that the examples in the present specification are not intended to limit the scope of the application.
EXAMPLES
With reference to the table below, various samples of microsphere compositions have been tested. It will be appreciated that the temperature activation ranges are dependent on the intended uses and as such on which type of thermal energy is applicable for curing/bonding/debonding. We have found that a typical composition for direct automotive glazing should comprise about 3% microspheres in the cleaner and 5% in the primer for thermosetting adhesives and 5-10% for thermoplastic adhesives. For metal bonded surfaces the composition should be in the range 5-10% at their interface surfaces in the absence of a primer. In the instance where the adhesive layer is of a comparable thickness to the diameter of the microsphere and can be activated on both sides of the layer about 5% of microspheres is required.
Average
Activation
Diameter
Range
Activation
Ref
(μm)
(C./Watts)
Source
Use
90
30-50
80-100 C.
IR; Air; UV;
Curing adhesive
Water
compositions
91
10-50
110-220 C.
IR;
Automotive,
500-1500
Electricity
aircraft and
Watts
train glazing,
car parts and
panels
820a
10-30
150-180 C.
IR;
Plastic
Electricity
composite -
glass layers
820b
Approx
100-120 C.
IR;
Aircraft glazing
4
Electricity
Floor covering
93-98
10-40
150-180 C.
IR;
Aluminium or
Electricity
other sheet
metal-
plastic layers
98-120
4-10
100-120 C.
IR; Hot
Dispersion of
air vapour
nanoparticles
on their porous
initial shell
surface to
avoid clustering
in a mix with
plastic binders
and solvents
551
4-10
40-80 C.
Hot water
Decorative paper,
or air; IR;
dentistry,
UV; laser or
medical surgery,
concentrated
sports equipment
light systems | The present invention relates to a system and a method of improving the debonding of two or more surfaces together. The invention utilises thermoexpanadable microspheres and thermal energy to debond interfaces in an adhesive system or as vehicle carriers. It also discloses a method of curing the adhesive system prior to the debonding step so that the same adhesive system may be used for both phases. It is especially useful in the automotive industry for end of vehicle life dismantling. | 1 |
FIELD OF THE INVENTION
[0001] The present invention is directed to a system for the thermoregulation of devices in industrial process plants operating at high temperatures, particularly dies for die-casting, dies for chill casting and the like.
STATE OF THE ART
[0002] The afore said dies may also work at higher temperatures, for example about 350° C. and higher. For their correct use in the die forming process field, they have to be thermoregulated, at least by cooling them where their temperature tends to extreme and inadmissible values.
[0003] Usually, the cooling is carried out by means of a heat-transfer fluid, such as water or diathermic oil, coming from a tank and circulated in ducts obtained in the die and subsequently in a heat exchanger to be cooled in its turn before its return to the tank.
[0004] According to main art, the cooling fluid, in case of water, is contained in a pressurized tank and it is circulated in a high-pressurized closed circuit of about 169 Bar at 350° C., for example, the latter entailing relevant structural problems about sealing and safety of the circuit itself.
[0005] In a previous Patent IT 1 368 475 of the same Applicant, it is described and claimed a system for the thermoregulation of dies for die-casting, dies for chill casting and the like, comprising an open tank containing a liquid cooling fluid, particularly water, a primary hydraulic circuit for a circulation of said liquid fluid from said tank to the die to be thermoregulated and from the latter to the tank through a heat exchanger. The primary circuit is integrated with the secondary circuit intended for the circulation of a gaseous fluid, typically air, in the die to be conditioned both in alternative and in a mixed form with the liquid fluid, and with a unit for controlling and operating the primary hydraulic circuit and the secondary pneumatic circuit for the system operation and for thermoregulating the die with the only liquid fluid, with the only gaseous fluid or the gaseous fluid mixed with the liquid fluid.
[0006] This system is workable and reliable, advantageously allowing the circulation of the liquid heat-transfer fluid with pressure levels relatively low, but it is only suited for cooling the dies.
[0007] However, in the practice it is sometimes required and convenient, to better operate and accelerate the start of the die forming process, also a pre-heating of the dies at a temperature of 140-160° C., for example, anyway lower than the real working temperature of the same dies.
[0008] The pre-heating may be carried out with the liquid fluid returning from a die and collected in the system tank after its passage through the heat exchanger, but the fluid temperature in the tank, usually in the range of 90-100° C., is not in itself sufficient for an appropriate die heating. On the other hand the die pre-heating with a liquid fluid heated up to the desired temperature in the same tank of the thermoregulating system, or in another additional tank, if not in pressurized conditions, may lead to the undesired vapor formation, thermal loss and energy consumption.
OBJECTS AND SUMMARY OF THE INVENTION
[0009] The present invention has been designed to satisfy this need too and, as a matter of fact, it is its main object to establish the conditions, in addition to for the die cooling with a liquid and/ or gaseous fluid at relatively low pressures, also for the pre-heating of the dies themselves up to a desired temperature from time to time.
[0010] A further object of the invention is then to provide a system for the thermoregulation of dies in which a cooling circuit and a heating circuit are combined and integrated, particularly in dies for die-casting, dies for chill casting and the like, operating with relatively high temperatures.
[0011] These objected are reached, according to the invention, by a thermoregulation system according to the preamble of claim 1 and characterized in that the system further integrates means to pre-heat the water and a hydraulic circuit to pre-heat the die or chill with the hot water coming from said means.
[0012] Advantages of an integrated pre-heating and cooling system for dies, further to those related in the afore said Patent IT 1 368 475 concerning the possibility of water and air use, both separately and together, the safety, the cleanness and the ecological and economical aspects, are evidently of being able to use an open storage tank of heat-transfer fluid, that is at atmospheric pressure, and to carry and use the same fluid for two modes: pre-heating and cooling, alternatively, in the same plant, but with the fluid intended for the pre-heating having the possibility of being generated under pressure out of the storage tank to obviate to the vapor formation at the required temperatures in the die pre-heating.
BRIEF DESCRIPTION OF THE DRAWING
[0013] Further details of the invention will be evident by following description made with reference to the attached drawing in which the only FIGURE shows a general scheme of the system.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Therefore and as it is represented the system for the thermo-regulation of a die or chill 10 comprises essentially an open storage tank 11 , a primary hydraulic circuit 12 , a secondary pneumatic circuit 13 and an auxiliary pre-heating circuit 112 connected to the primary hydraulic circuit.
[0015] The storage tank 11 has a volume of heat-transfer fluid, preferably water loaded therein and then filled up if necessary through a supply line 14 having a filter FA and a loading solenoid valve EV 1 . The fluid level in the tank 11 is controlled by a level sensor SL and overflow device 15 .
[0016] The primary hydraulic circuit 12 has a delivery line 12 ′ from the tank to the die 10 and a return line 12 ″ from the die to the tank, whereas the pneumatic circuit 13 is connected to the delivery line 12 ′ of the primary circuit by means of an ejector EJT.
[0017] Along the delivery line 12 ′ at least a recirculation pump P 1 and, downstream this but upstream the ejector EJT, a solenoid valve EV 4 with adjustable opening and, downstream said ejector, a delivery pressure switch Pm 1 , to operate the minimum pressure in the same line 12 ′, a manometer M 1 and a safety valve VS are inserted. In the length between the recirculation pump P 1 and the solenoid valve EV 4 , the delivery line 12 ′ is reconnected to the storage tank 11 through the bypass line 16 having an on/off valve EVBP.
[0018] The return line 12 ″ passes through at least one heat exchanger SC and it may be provided with a possible pressure switch to operate the minimum return pressure and with a regulation metering valve DRL. In its turn the heat exchanger SC is fed with a cooling fluid through inlet and outlet lines 17 under the control of a solenoid valve EV 5 on the inlet line.
[0019] The pneumatic circuit 13 is provided for the circulation of a aeriform fluid, typically air, and it is connected to the delivery line 12 ′ of the hydraulic circuit 12 through the ejector EJT and it comprises at least one manometer M 2 , an inlet solenoid valve EV 2 and a non-return valve VR 1 .
[0020] The hydraulic pre-heating circuit 112 of the die is substantially ring-shaped in its inside and it is integrated with the so far described system. According to the invention, on the return line 12 ″ of the primary circuit 12 a three-way solenoid valve EV 5 is inserted, and the pre-heating circuit 112 comprises a delivery line 112 ′ towards the die, preferably in common and coincident with the same delivery line 12 ′ of the primary hydraulic circuit 12 , and a return line 112 ″ extending from an outlet of said three-way valve EV 5 until it joins with the delivery line 12 ′, 112 ′ common with the primary 12 and the pre-heating 112 circuits, in a part upstream the recirculation pump P 1 .
[0021] Further, on the common line 12 ′, 112 ′ of the two primary and pre-heating circuits 12 , 112 a second tank 111 is inserted, the latter containing water too and being provided with an electric resistor R to heat and maintain the temperature of the liquid herein contained.
[0022] In the represented example, such a second tank 111 is positioned downstream the recirculation pump P 1 , between the latter and the ejector EJT. It is further provided with a thermal probe S 3 to detect the water temperature in its inside and with a vent line 111 ′ with a vent solenoid valve EV 6 , connecting it to the return line 12 ′ of the primary hydraulic circuit downstream the three-way solenoid valve EV 5 , that is downstream the heat exchanger SC.
[0023] To supply and circulate the pre-heating water from the second tank 111 towards the die 10 and from the latter to the same second tank a second pump P 2 , or pressurization pump, may be provided, which is inserted on the delivery line 12 ′, in the represented example, from the storage tank 11 to the die 10 . Alternatively the circulation of the pre-heating fluid in the pre-heating circuit 112 may be realized by the same recirculation pump P 1 , conveniently positioned and activated, of the cooling fluid.
[0024] The plant may be further comprise a temperature probe: S 1 of the water in the storage tank, a temperature probe S 2 at the die 10 , as well as a non-return valve VR 2 , an expansion vessel 114 , a pressure switch Pm 2 and a manometer M 3 on the line of the second pump P 2 .
[0025] The system of the invention may operate according to three different modes:
[0026] 1. to alternatively cool the die with high pressurized air/ water (up to about 14 Bar);
[0027] 2. to cool the die with air mixed with water at low pressure (about 1-2 Bar);
[0028] 3. to pre-heat the die with hot pressurized water all controlled by an electronic device (PLC) programmed to manage the readings coming from the number of controlling instruments and the instruments for opening and closing the solenoid valves.
[0029] Instead the opening/closing of the valves VBP and DRL on the primary circuit may be carried out manually.
[0030] In the first working mode, the water that is withdrawn from the storage tank and circulated in the primary circuit 12 by the recirculation pump 12 represents the main cooling fluid. The system has areas with different pressures and temperatures allowing anyway the cooling water not to ever evaporate. On the other hand, the air could then be used both for adjusting the water temperature, in case of insufficient cooling of the die, and as cooling emergency fluid, with security functions in response to different alarms and/or failures of the recirculation pump P 1 or other components of the primary hydraulic circuit 12 .
[0031] When the cooling system is started, the recirculation pump P 1 is stopped, the inlet solenoid valve EV 2 of the pneumatic circuit 13 is open to admit air into the hydraulic circuit 12 and the solenoid valve EV 1 opens to fill water into the vessel/tank 11 under the control of a level sensor SL. After a predetermined time, and if the pressure and temperature parameters in the system are within given thresholds, the solenoid valve EV 2 closes and the pump P 1 starts, thereby activating the water cooling of the die or chill 10 . During the cooling, the water in the tank 11 maintains a temperature lower than 90° C., the pressure in the delivery line 12′ of the primary hydraulic circuit 12 is relatively high, the water enters into the die or chill 10 and it comes out heated at a temperature of about 180-200° C., and then it comes back to said tank after it has passed through the heat exchanger, in which it is cooled and taken back to a temperature of 90° C.
[0032] The water remains pressurized until the metering valve DRL, adjusted and operating to assure a minimum passage of water, to maintain the desired pressure in the hydraulic circuit upstream the valve itself, and to lower the water pressure from the side of its exit towards the vessel or tank.
[0033] The secondary pneumatic circuit 13 starts operating automatically when controls, alarms or failures in the hydraulic circuit ask for, anyway under the control of the programmed electronic device (PLC) and programmable according to requirements.
[0034] During the air cooling, the pump P 1 is stopped and the valve EV 2 is open, the air arrives to the delivery line 12 ′ through the ejector EJT and it runs through the circuit in the same direction of the cooling water, flushing out the pipes from the water itself and determining a die cooling until when the conditions allowing a correct water cooling are restored.
[0035] With the second working mode, the circuit pressure remains almost constant as time goes by, depending on the air pressure. The working pressure is then relatively low, 1-2 Bar, as afore said.
[0036] Then the main cooling fluid is become the air which, through the ejector EJT, is mixed with water in the desired and determined quantity by means of the solenoid valve EV 4 driven by the operating electronic device.
[0037] As a result of a local and/or remote signal of cooling start, then there are two possibilities.
[0038] a. The die cooling only with air, for which the solenoid valve EV 2 opens for entering air, the pump P 1 starts, the valve VBP on the bypass line 16 is opened, whereas the solenoid valve EV 4 on the delivery line 12 ′ is closed for the return of water into the tank; then an air flow runs through the circuit, entering from the ejector EJT then to circulate in the die and exit into the tank.
[0039] b. The die cooling with air mixed with water, for which the pump P 1 is started, if not started yet, and the solenoid valve EV 2 for entering air is open as the valve BHP is open on the bypass line 16 . In the same time an electronic control (PLC) operates the opening of the solenoid valve EV 4 to measure out the correct quantity of water to be circulated with the air entering from the ejector EJT.
[0040] In the pre-heating mode of the die or chill 10 , the water contained into the second tank 111 , preventively loaded with water that may come from the storage tank 111 , is used.
[0041] Then the recirculation pump P 1 is still inactive, the solenoid valve EV 4 on the delivery line 12 ′ of the primary hydraulic circuit 12 is open and the three-way solenoid valve EV 5 on the line 12 ″ returning from the die or chill is switched so that such a valve is closed at the side connected with the exchanger and it is open at the side connected with the return line 112 ″ of the pre-heating circuit 112 .
[0042] In these conditions, the water may be heated in the second tank 111 by the electric resistor and then it is supplied by the pump P 2 towards the die or chill 10 for its pre-heating, for example to a temperature of 140-160° C. The water exiting from the die passes through the three-way solenoid valve EV 5 for its return to the second tank 111 through the return line 112 ″ of the pre-heating circuit 112 .
[0043] Then the controlling electronic device, both independently, and interacting with outer interfaces, will be programmed to operate the subsequent steps:
switched on system, but inactive for cooling the die as it is supplying neither air nor water; cooling of the die only with air; cooling the die with air mixed with water in different required modulations; pre-heating of the die with hot water coming from a second tank provided with a heater. | The invention concerns a system for the thermoregulation of dies for die-casting, dies for chill casting and the like. It comprises a tank ( 11 ) containing a cooling fluid; a primary hydraulic circuit ( 12 ) for a circulation of the cooling fluid from the tank to the die to be cooled and from this to the tank through a heat exchanger (SC); a secondary pneumatic circuit ( 13 ) connected to the primary hydraulic circuit ( 12 ) for the circulation of an aeriform fluid in the die to be cooled both in alternative, and in a mixed form with the liquid cooling fluid; and a pre-heating hydraulic circuit ( 112 ) integrated with the primary hydraulic circuit ( 12 ) and assigned to the production and circulation of a hot liquid fluid for pre-heating the die to be thermoregulated. | 1 |
RELATED APPLICATIONS
[0001] This application claims priority to European Patent Application 14157362.6, filed Feb. 28, 2014, the disclosure of which is incorporated in its entirity herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates, in general, to elevator systems and, in particular, to actively controlling the natural frequency of tension members.
BACKGROUND OF THE INVENTION
[0003] Tension members or means such as ropes and cables are subject to oscillations. These members can be excited by external forces such as wind. If the frequency of exciting forces matches the natural frequency of the tension member, then the tension member will resonate.
[0004] High velocity winds cause buildings to sway back and forth. The frequency of the building sway can match the natural frequency of the elevator causing resonance. In resonance, the amplitude of the oscillations increases unless limited by some form of dampening. This resonance can cause significant damage to both the elevator system and the structure.
[0005] Two major problems plague high rise elevators with long hoist ropes and correspondingly long compensation ropes. These are rope sway and re-leveling due to rope elongation. Rope sway, particularly compensation rope sway, is a major problem in high rise buildings.
[0006] The fundamental frequency (also called natural frequency) of a periodic signal is the inverse of the pitch period length. The pitch period is, in turn, the smallest repeating unit of a signal. The significance of defining the pitch period as the smallest repeating unit can be appreciated by noting that two or more concatenated pitch periods form a repeating pattern in the signal. In mechanical applications a tension member, such as a suspension rope, fixed at one end and having a mass attached to the other, is a single degree of freedom oscillator. Once set into motion, it will oscillate at its natural frequency. For a single degree of freedom oscillator, a system in which the motion can be described by a single coordinate, the natural frequency depends on two system properties; mass and stiffness. Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations of an oscillatory system.
[0007] Because of a low mass of a compensation sheave around which a compensation rope is wound, the natural frequency of the compensation ropes is very low and is normally between 0.05 Hz and 1 Hz. The following equation (Equation 1) can used be to calculate the natural frequency of compensation ropes in Hz:
[0000]
f
n
=
n
2
L
g
(
M
2
n
c
m
+
L
2
)
(
1
)
[0000] where g=9.81 m/s 2 is the acceleration of gravity, n denotes the vibration mode number, n C is the number of ropes, L is the length of the rope (in m), M represents mass of the compensating sheave assembly (in kg), and m is mass of the rope per unit length (in kg/m).
[0008] High rise buildings are known to sway during windy conditions. The frequency of the building sway is generally between 0.05 and 1 Hz. Because the natural frequency of the compensation ropes is very close to the natural frequency of the building, resonance often occurs. Compensation rope resonance can cause the ropes to strike the walls and elevator doors causing damage and frightening passengers.
[0009] The U.S. Pat. No. 8,123,002 B2 discloses a system and method for minimizing compensation rope sway by altering the natural frequency of compensation ropes using servo actuators. The rope sway is minimized by moving the compensation sheave of the compensation rope to modulate tension of the compensation rope or to adjust the position of the termination of a compensation rope to account for changes in the position of a structure.
SUMMARY
[0010] The invention seeks to provide an effective and cost effective way of minimising rope sway, thus avoiding rope resonance.
[0011] Thus, an elevator system comprising the features of claim 1 is suggested. The invention provides an efficient and reliable means of minimising compensation rope sway, thus preventing compensation rope resonance effects, by providing the traction sheave with tension means for inducing a variation of the tension of the compensation rope. Advantageously, according to the present invention, rope sway may be minimized without having to manipulate a compensation sheave provided in the lower part of the shaft. Be it added that in case of the traction sheave being coaxially coupled to the shaft of the hoist motor, it is also possible to provide tension means according to the invention (such as servo actuators, as will be further detailed below) which act on the hoist motor. This is also understood to fall under the wording of the traction sheave being provided with tension means. Also, the hoist motor itself can constitute tension means for the compensation rope, for example by providing an oscillatory movement for the traction sheave, as will be further detailed below.
[0012] Advantageously, the means to induce a variation of the rope tension of the compensation rope comprises at least one servo actuator, which is adapted to adjust the position of the traction sheave. Especially, it is possible to adapt or control the vertical position of the traction sheave within the elevator shaft. For example, by means of raising the position of the traction sheave within the elevator shaft, the elevator car and the counterweight will be accordingly raised. Hereby, a compensation rope, which is wrapped about a compensation sheave in the lower part of the shaft, will be tensioned. It is also conceivable to adjust the horizontal position of the traction sheave within the elevator shaft.
[0013] Advantageously, the tension means comprise means for variation of the angular speed and/or providing an oscillatory movement of the traction sheave. These means can be embodied by the hoist motor of the elevator system, which drives the traction sheave, as mentioned.
[0014] Expediently, the elevator system comprises a controller, which is adapted to compare the natural frequency of a building structure, within which the elevator system is provided, with the natural frequency of the compensation rope, and to direct the servo actuator to adjust the position of the traction sheave, if the compared frequencies are substantially similar, especially if the difference between the determined frequencies is smaller than a predetermined threshold value. This provides a reliable criterion for evaluating at what times the variation of the tension of the compensation rope is required.
[0015] According to a further preferred embodiment, the means to induce a variation of the rope tension of a compensation rope can comprise means for adjusting the angular position and/or angular speed of the traction sheave. For example, by means of introducing a vibrational or oscillating movement of the traction sheave, the length of the compensation rope between the compensation sheave and the elevator car (and correspondingly between the compensation sheave and the counterweight) can be slightly varied leading to a modification of the tension of the compensation rope whereby rope sway can be effectively acted against.
[0016] According to a further preferred embodiment, the compensation sheave is provided in a moveable manner, wherein at least one servo actuator is provided to adjust the position, especially the vertical and/or horizontal position, of the compensation sheave. Hereby, an additional means for minimizing compensation rope sway by altering the natural frequency of the compensation rope is provided. Especially, based on the observation that the first and second vibration modes are the most problematic modes, the first mode could be counteracted by the traction sheave (and/or the hoist motor) being provided with tension means to induce a variation of the tension of the compensation rope, especially by adjusting the position of the traction sheave, as described above, and the second mode by means of adjusting the position of the compensation sheave, or vice versa.
[0017] Advantageously, the means provided with the traction sheave to induce a variation of the rope tension of the compensation rope are provided as at least one servo actuator.
[0018] Advantageously, the at least one servo actuator for adjusting the position of the traction sheave and/or the at least one servo actuator for adjusting the position of the compensation sheave is adapted to adjust the positions of traction sheave and compensation sheave respectively within defined ranges. This adjustment can be effected to ensure that the natural frequency of the compensation rope is sufficiently different from that of the building structure, within which the elevator system is provided.
[0019] Advantageous embodiments of the invention will now be described with reference to the accompanying drawings. It is to be understood that this invention is not limited to the precise arrangement shown. Especially, individual features shown in the context of the drawings and/or described with reference to the preferred embodiments shall be considered disclosed on their own or in any other feasible combination of other features thus shown.
[0020] Further advantages and embodiments of the invention will become apparent from the description and the appended figures.
[0021] It should be noted that the previously mentioned features and the features to be further described in the following are usable not only in the respectively indicated combination, but also in further combinations or taken alone, without departing from the scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0022] FIG. 1 illustrates a first preferred embodiment of an elevator system according to the invention,
[0023] FIG. 2 illustrates a preferred version of a PID controller that may be used in association with the elevator system of FIG. 1 ; and
[0024] FIG. 3 illustrates a second preferred embodiment of an elevator system according to the invention.
DETAILED DESCRIPTION
[0025] Referring to FIG. 1 , a general design of an elevator system 10 is shown. It comprises an elevator car 18 and a counterweight 20 , which are connected to one another via a hoist rope 19 constituting a suspension (support) means. Obviously, the suspension means could be embodied as a plurality of hoist ropes, or belts.
[0026] The hoist rope 19 is wrapped around a traction sheave 40 , which is driven by a hoist motor 42 , which is shown purely schematically. Especially the hoist motor 42 can be provided coaxially with respect to a shaft 40 a of traction sheave 40 , e. g. in the view of FIG. 1 behind the traction sheave.
[0027] The elevator system 10 comprises one or more servo actuators 44 interacting with the traction sheave 40 . In case of a coaxial arrangement of traction sheave and hoist motor the servo actuator(s) can interact with the hoist motor. The servo actuator 44 is configured to move the traction sheave vertically within a predetermined range u 1 (t). Such a vertical movement has to be performed at as suitable frequency and amplitude, preferably according to suitable feedback control algorithms.
[0028] Also, by means of hoist motor 42 , which under normal operating conditions serves to rotate the traction sheave 40 in one angular direction over a sufficient period of time to transport elevator car 18 e.g. from a first landing to a second landing, the traction sheave 40 can perform a rotational oscillatory movement. This is symbolized by double arrow 46 . Such an oscillatory movement has to be performed at a suitable frequency and amplitude, again according to suitable feedback control algorithms. Typically there will be different frequencies and angular displacements depending on specific operating conditions. For example, when the elevator car is moving, the rope length continuously changes, which leads to a corresponding continuous change in its natural frequency. Thus, during such movement, there is less time for the rope displacement to grow with resonance.
[0029] However, when the elevator car stops moving, i.e. is in a stationary position, the length and thus the natural frequency of the rope will be constant, and the displacement amplitudes will be able to increase. Therefore, in case of a moving elevator car, smaller compensation frequencies as well as angular displacements of the traction sheave will be sufficient, whereas larger compensation frequencies and angular displacements will be expedient in case of a stationary elevator car.
[0030] The elevator car 18 and the counterweight 20 are also connected by means of a compensation rope 16 , which is wrapped around a compensation sheave 14 in the lower part of the elevator shaft. The compensation rope 16 is fixed at a first end to the underside of the elevator car 18 , and at a second end to the underside of the counterweight 20 .
[0031] The compensation rope 16 may be affixed to the elevator 18 and/or counterweight 20 with a rope tension equalizer such as that described, for example, in U.S. Pat. No. 8,162,110. Any suitable rope, such as aramid or wire rope, may be used in accordance with versions described herein. In one version, rope having a relatively high natural frequency may be used.
[0032] The position of the compensation rope 16 relative to the building is also a factor in determining whether resonance will occur. Referring again to FIG. 1 , the compensation rope 16 may be attached to terminations on the bottom of the elevator car 18 and/or counterweight 20 associated with a first moveable carriage 30 and a second moveable carriage 32 , respectively. In one version, the first and second moveable carriages are moveable in both the front to back (X) and side to side directions (Y). Attached to the carriage are a plurality of servo actuators 34 , 36 that move the first and second moveable carriages in the X and Y directions. Movement of the location of the termination of the compensation rope 16 may help prevent the elevator system 10 from entering into resonance with the building by shifting the frequency of the compensation rope 16 .
[0033] In the version of the elevator system 10 shown in FIG. 1 , one or more servo actuators 44 , as described above, are modulated in response to a control algorithm that actively damps the oscillation of the ropes by varying the tension in the compensation ropes by means of manipulation of the traction sheave 40 . The term “tendon control” in this connection refers to actively adjusting the tension or active suppression of a tension member or compensation rope to alter the natural frequency of the tension member.
[0034] The servo actuator 44 may be a servomotor, servomechanism, or any suitable automatic device that uses a feedback loop to adjust the performance of a mechanism in modulating tendon control. The actuators could be hydraulic piston and cylinders, ball screw actuators, or any actuator commonly used in the machine tool industry. In particular, the servo actuator 44 may be configured to control the mechanical position of the traction sheave 40 along a vertical axis by creating a mechanical force to urge the traction sheave 40 in a generally upward or downward direction. Mechanical forces may be achieved with an electric motor, hydraulics, pneumatics, and/or by using magnetic principles.
[0035] In one version, the servo actuator 44 operates on the principle of negative feedback, where the natural frequency of the compensation rope 16 is compared to the natural frequency of the building as measured by any suitable transducer or sensor. A controller (not shown) associated with the servo actuator 44 may be provided with an algorithm to calculate the difference between the natural frequency of the compensation rope 16 and the natural frequency of the building. If the difference between these frequencies is within a predetermined range, the controller may instruct the servo actuator 44 to adjust the position of the traction sheave 14 and thus, for example, the tension of the compensation rope 16 so that any swaying motion of the rope is actively damped. It will be appreciated that any suitable feedback control theory may be applied to versions described herein.
[0036] In one version, to measure the natural frequency of a building, an accelerometer is positioned in the elevator machine room or any other suitable position, for example in the elevator shaft, and the output of the accelerometer is twice integrated to produce displacement. During periods of high velocity winds the building will sway. The twice integrated output of the accelerometer may be used to determine the displacement of the machine room from its normal location.
[0037] Several control strategies can be applied to affect tendon control such as, for example, bilinear control, positive integral force feedback, exponential stabilization, proportional, integral, and derivative (PID) feedback, and fuzzy logic control. Any suitable control means may be associated with the controller to modulate the natural frequency of the compensation rope 16 . Any suitable active vibration control (AVC) techniques involving actuators to generate forces and applying them to the structure in order to reduce its dynamic response may be utilized.
[0038] Referring to FIG. 2 , the rope sway may be modulated, for example, by a PID controller that monitors the natural frequencies of the compensation rope 16 and the building to prevent resonance. Modulating the natural frequency of the compensation rope 16 in the disclosed manner allows for the tension member to be actively damped. FIG. 2 illustrates a schematic of one version of a proportional-integral-derivative controller or “PID controller” that may be used to actively damp a tension member. The PID controller may be implemented in software in programmable logic controllers (PLCs) or as a panel-mounted digital controller. Alternatively, the PID controller may be an electronic analog controller made from a solid-state or tube amplifier, a capacitor, and a resistance. It will be appreciated that any suitable controller may be incorporated, where versions may use only one or two modes to provide the appropriate system control. This may be achieved, for example, by setting the gain of undesired control outputs to zero to create a PI, PD, P, or I controller.
[0039] It will be appreciated that any suitable modifications to the PID controller may be made including, for example, providing a PID loop with an output deadband to reduce the frequency of activation of the output. In this manner the PID controller will hold its output steady if the change would be small such that it is within the defined deadband range. Such a deadband range may be particularly effective for actively damping tension members where a precise setpoint is not required. The PID controller can be further modified or enhanced through methods such as PID gain scheduling or fuzzy logic.
[0040] Referring now to FIG. 3 , a further preferred embodiment of the invention is shown, which comprises an adjustable traction sheave 40 as described in connection with FIG. 1 , as well as an adjustable compensation sheave 14 , provided in the lower part of the elevator shaft.
[0041] This embodiment differs from the embodiment of FIG. 1 only in that compensation sheave 14 is also moveable by means of at least one servo-actuator 12 . Thus, parts already described with reference to FIG. 1 are provided with the same reference numerals. The servo actuator 12 is configured to move the compensation sheave 14 vertically within a predetermined range u 2 (t). It is also possible to move compensation sheave 14 horizontally.
[0042] All observations made above with respect to the traction sheave 40 are also applicable to the compensation sheave 14 . Especially, the actuator 12 can be modulated in response to a control algorithm that actively dampens oscillation of the compensation ropes. Here again, the servo actuator 12 may be a servo motor, servo mechanism or any other suitable automatic device that uses a feedback loop to adjust the performance of a mechanism in modulating tendon control. Again, the actuators can be hydraulic pistons and cylinders, or any other embodiment as described above. The servo actuator 12 can also operate on the principle of negative feedback, as described above.
[0043] Especially, it is advantageously possible to provide a controller associated with the servo actuators 44 and 12 , and provide this with an algorithm to calculate the difference between the natural frequency of the compensation rope 16 and the natural frequency of the building, as described above.
[0044] The described adjustment of the traction sheave and of the compensation sheave can advantageously be combined, for example in that adjustment of the traction sheave serves to address a first vibration made of the compensation rope, and adjustment of the compensation sheave to address the second vibration mode, or vice versa. | One elevator system includes an elevator car, counterweight, traction sheave, support wrapped around the traction sheave and suspending the car and the counterweight, a compensation sheave, a compensation member wrapped around the compensation sheave and being affixed at a first end to the elevator car and at a second end to the counterweight, and a tensioner. The support is driven by rotation of the traction sheave to raise and lower the car, and the tensioner is in communication with the traction sheave for linearly displacing a rotational centerpoint of the traction sheave. Another elevator system has an elevator car, counterweight, compensation sheave, compensation rope wrapped around the compensation sheave and being affixed to the car and the counterweight, a traction sheave driving a support suspending the car and the counterweight, and a tensioner in communication with the traction sheave for inducing a variation in tension of the compensation rope. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention concerns a device and a method for processing a robot control program.
[0003] 2. Description of the Prior Art
[0004] The movement path of the center of a tool connected with the robot (thus the tool center point (TCP)) is designated as a robot path of a robot while, insofar as the position of the robot itself is discussed in the following, the position of the base or the pedestal of the robot or, respectively, of the zero point of the robot or global coordinate system is designated relative to the path. The points in the path course that have been taught or programmed offline and normally serve as support points for interpolation of the goods course between these points (for example in the scope of a spine interpolation) are designated as support points of a robot path or, respectively, a path course.
[0005] EP 0 852 346 discloses a device to display a robot program, with a memory device to store the robot program; a display device at which a position can be designated with a pointer device; and with a processing device to display a work interval and an air intersection interval as successive lines, with presentation of one of the lines if this is designated by the pointer device, wherein the presentation corresponds to a command for a work priority in the robot program in connection with one of the displayed lines.
[0006] Given use of industrial robots, it frequently occurs that data from support points of an existing robot control program (abbreviated as: robot program) must be changed. This can result from a modification requirement for an existing robot program, for example when the module to be processed has been slightly modified. However, point data must also frequently be adapted in order to achieve a required clock time. These point corrections are normally conducted “online”, i.e. while the robot program is executed.
[0007] In order to conduct such an “online correction” of a point in space, knowledge of a reference system is required of the robot controller. In this simplest case, this is the global coordinate system of the robot. However, an (external) tool coordinate system or an otherwise defined coordinate system is also frequently used. A point correction can then be conducted relative to this; but the user must thereby translate the actual correction direction and correction size of the point relative to the robot path into corresponding X, Y and Z values of the local reference system.
[0008] The correct values to be input can hardly be intuitively determined by the operator since the reference system at the point to be corrected is not visible. In practice, for the most part multiple iterations are required for adaptation of the X, Y and Z values in order to exactly achieve the desired point correction. It is clear that this method has a large potential for error due to its initial imprecision.
[0009] It is known to register graphically represented path points by means of an optical system such as a light intersection sensor, wherein an adaptation of path points of the robot program ensues via graphical editing and, for changes to graphical 2D representations, are converted back into a 3D position change and are transferred into the robot program. However, no support is thereby given to the user with regard to the classification and orientation of a path point to be edited in the course of the robot path.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a user with a simple online correction while avoiding the cited disadvantages, and to provide the user with tools for an intuitive manual correction so that he or she can modify the location of a selected support point matching the local conditions without repeatedly matching the local conditions.
[0011] According to the invention, the above object is achieved by a device of the aforementioned type with a device to display at least one local region of a robot path of a robot to support a modification of a location of a support point of the robot path, a device to display the support point to be changed, the path course through this support point and at least one direction through the support point, perpendicular to the path course; and a device to modify the path course. To achieve the above object, the invention furthermore provides a method of the aforementioned type in which at least one local region of a robot path of a robot (said robot path provided by the robot program) is adapted to support a change of a location of a support point; and the support point to be changed, the path course through this and at least one direction through the support point perpendicular to the path course are displayed; and wherein the robot program is automatically correspondingly adapted after changing the displayed elements of the robot path.
[0012] With the invention, path or support points are read out from the robot program and indicated to the user for online adaptation by means of graphical assistance elements, such that a modification via graphically oriented editing can occur. The conversion between different coordinate systems is taken away from the user, which leads to a distinct reduction of the robot operation complexity.
[0013] In a preferred embodiment, the path course is presented as tangent to the robot path at the support point, so a simple and clear representation is provided.
[0014] In an additional preferred embodiment, it is provided that a plane perpendicular to the path course is displayed, wherein in particular the plane is displayed at least as a circular disc. In a development of this, it can be provided that the plane is displayed as an outer ring with an offset inner circular disc. Through this presentation, the user is enabled to specify the direction change of the location of the support point to be corrected by an angle relative to the cited direction, perpendicular to the path course in the cited plane.
[0015] To select a support point to be corrected, in an embodiment of the invention the course of the robot path is initially presented in a primary plane of a Cartesian coordinate system and/or in a selected plane. In order to render a selection more precisely, and if necessary to be remain below undifferentiated or un-discriminated support points in the representation of the entire path course, in an embodiment the representation of the path course can be enlarged.
[0016] According to the invention, a shift of the presented circular disc in the direction of its surface normal causes a shift of the support point on the programmed path in the robot control program; that a rotation of the arrow in the plane of the circular disc around its surface normal determines the correction direction in a plane perpendicular to the programmed path; and/or that a shift of the displayed support point along the arrow produces a displacement of the support point in the robot control program, perpendicular to the direction of the programmed path. The device according to the invention is advantageously fashioned in a corresponding manner.
[0017] So that the user can also purely intuitively register the position of the robot relative to the path course, it is provided that this is likewise graphically depicted, wherein the position of the robot is presented relative to the path course.
[0018] The device according to the invention is fashioned to reproduce the preceding depiction and graphical representations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 schematically illustrates an embodiment of a device according to the present invention.
[0020] FIG. 2 illustrates display of a local region of a robot path to support modification of the location of a support point, in accordance with the present invention.
[0021] FIG. 3 shows an initial representation at the display for selection of a support point to be corrected in terms of its location with the device of FIG. 1 .
[0022] FIG. 4 shows the illustration of FIG. 1 , with the path course enlarged.
[0023] FIGS. 5 a and 5 b respectively illustrate the use of the device according to the invention to display steps in the method according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The device A according to the invention essentially has a processing device (computer) B, a display device (C) and at least one input device (D) such as a keyboard ( FIG. 1 ).
[0025] To facilitate the correction—in particular the online correction of the support point as it is required for, for example, interpolation of the path course by means of a spline method and was normally taught or even programmed offline—the invention initially provides the depiction of a point to be changed and, as a further tool in addition to this, initially provides a representation for the path course through point 1 —in the shown exemplary embodiment, in the form of a tangent 2 relative to the path course through point 1 ( FIG. 2 ). The movement direction is indicated by an arrowhead 3 at the end of the tangent 2 .
[0026] An artificial line 4 (here a dashed line) through the support point to be corrected at a right angle to the path course or, respectively, the tangent 2 representing this and in the correction plane is shown as an additional orientation aid. This artificial line 4 also forms an “artificial horizon”. To illustrate the plane perpendicular to the path course or, respectively, the tangent 2 , an inner circular surface 5 is shown through the support point 1 in which the dashed artificial line 4 also lies, as well as circular ring 6 surrounding the surface 5 . The shown elements 1 through 6 can be formed with different colors. The circular disc 5 around the support point 2 can in particular indicate the correction limits within which a correction of the location of the support point whose location is to be corrected can be produced. In the shown exemplary embodiment, an arrow that represents the correction direction of the desired spatial correction (aligned at an angle of, for example, 15°) is furthermore designated with 7 .
[0027] The desired correction can be input via associated keys or as a numerical value in the lower half of the representation from FIG. 1 , or even via typical input with the aid of a computer input means (such as a computer mouse) in that the origin point of the arrow 7 is moved along the tangent 2 and the end point of the arrow 7 is moved on the circle representation 5 , 6 . Located in the lower display field are maximum correction values for the path correction along the path course or, respectively, the tangent 2 (with ±3 mm in the shown exemplary embodiment and with a maximum of 5 mm perpendicular to this), while the angle can be freely selected in the entire plane of the discs 5 , 6 .
[0028] The selection of the support point to be corrected can be made corresponding to the representations of FIG. 3 and 4 .
[0029] The right upper window representation in FIG. 2 shows the path course 8 in the selected correction plane, here in the X-Y plane of a Cartesian coordinate system (as is indicated in the left lower corner of this window representation). On the path course, the support point 1 ( FIG. 2 ) to be corrected (which is selected from a point list in the left window portion in FIG. 2 ), which is designated with C — 005, for example, is selected and emphasized. Furthermore, the position of the robot 9 is represented by a schematic depiction of such a robot 9 relative to the path course 8 .
[0030] The representation of the path course can be enlarged, as this is presented in FIG. 3 . Furthermore, given such an enlargement the movement direction can be reflected by an arrow 3 corresponding to FIG. 2 . The location of the robot 9 relative to the path course 8 is represented by a marking 10 at the edge of the presentation region in the enlarged depiction of FIG. 3 . Depending on the orientation of the location of the robot relative to the path course 8 , the marking can migrate around the presentation region for the path course 8 , thus also be located at a different location than shown in FIG. 3 .
[0031] The invention supports the operating mode of a user for correction of a support point or multiple support points of the movement path of a robot in the following manner:
[0032] First, according to FIG. 3 the user calls up the symbolic representation (left half) and graphical representation of the path course 8 with the individual support points. He then selects a support point 1 , be it in the symbolic reproduction to the left, be it on the graphical path course to the right. The user can then produce an enlargement of the path course via zooming. Furthermore, it is possible to show the path course not only in the reproduced X-Y plane of the Cartesian coordinate system but also in other primary plane of such a Cartesian coordinate system or in other desired planes, depending on which representation is most suitable for correction of the location of a support point.
[0033] If necessary, an enlargement of the depiction of the path course 8 can be effected in order to select for correction a different support point than that initially selected, if this appears to be necessary or more suitable in the enlarged depiction. A switch from the left symbolic representation to the graphical depiction in the left region of FIG. 2 then ensues, and the user can then produce a correction of the location of the selected support point 1 in the manner described above.
[0034] Since the two-dimensional reproduction in the right area of FIG. 2 through 4 contains a projection of the path course on the corresponding coordinate plane, it is not to be excluded that a point located in this reproduction actually represents two points in a path course, or, respectively, that these are no longer to be differentiated or, respectively, discriminated in the reproduction. If this is the case, in the representation from FIG. 1 the arrowhead 3 is not displayed as well, which indicates to the user that the path support point 1 shown there is not unambiguous and provides him with an inducement to select a different plane as a presentation or, respectively, projection plane in which the two points in question are differentiable.
[0035] The disc 6 of FIG. 5 a and 5 b schematically represents the tolerance range for a correction. The arrow 7 on the disc 6 symbolizes only the correction device. The length of the arrow does not vary.
[0036] After a correction, the middle point 1 in the graphic wanders outward on the arrow 7 (disc). The middle of the disc 6 represents the nominal point. The correction values are stored in offset data with reference to the nominal point. The disc edge thus represents the tolerance limit of the correction.
[0037] A correction ensues via colored, associated or otherwise differentiated arrows. For this the device according to the invention respectively possesses one + and one − key per correction device. A numerical input is likewise additionally possible.
[0038] 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 heron all changes and modifications as reasonably and properly come within the scope of their contribution to the art. | In a computerized device for processing a robot control program, at least one local area of a robot path of a robot is displayed at a display screen, the robot path containing a support point that is to be modified. The display screen also shows the support point, as well as a path course therethrough and at least one direction also proceeding through the support point perpendicularly to the path course. An input device allows a user to modify the path course by modifying the position of the support at the display screen. | 1 |
[0001] This application is a continuation of U.S. patent application Ser. No. 14/413,050, filed Jan. 6, 2015, which is a 371 national phase entry application of Patent Cooperation Treaty Application PCT/EP2013/001276, filed Apr. 29, 2013, which claimed priority from German Patent Application 10 2012 106 154.8, filed Jul. 9, 2012; all of which are incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to a cigarette paper. Particularly, it relates to a cigarette, which obtains higher dilution of the smoke, compared to a conventional cigarette paper of approximately equal air permeability, but which otherwise deviates chemically and physically as little as possible from a conventional cigarette paper.
BACKGROUND OF THE INVENTION
[0003] It is well known that cigarette smoke contains many harmful substances. Consequently, there exists an interest in the industry to produce cigarettes the smoke from which contains considerably fewer harmful substances. There are various approaches to reducing the amount of such substances. For example, cigarettes are often equipped with filters, typically made of cellulose acetate, which can absorb a part of the particulate phase of the smoke, generally called “tar”. Other methods aim to dilute the smoke generated in the cigarette, for example with an air flow flowing through a perforation in the tipping paper. In addition, by its defined air permeability, the cigarette paper wrapping the tobacco rod allows air to flow into the tobacco rod of the cigarette, which dilutes the smoke. Finally, the amount of harmful substances in the smoke of a cigarette can be influenced by selection of the tobacco blend.
[0004] Typical cigarette papers comprise cellulose fibers, among others, which are produced from wood, flax or other materials. In addition, mixtures of cellulose fibers of different origins are used.
[0005] A characteristic property of the cigarette paper of great technical importance is its air permeability. It describes the permeability of the paper to an air-flow, which is caused by a pressure difference between the two sides of the paper. More precisely, it describes the volume of air flowing through the paper per unit time, per unit area and per pressure difference and thus has the dimension cm 3 /(min cm 2 kPa), which is frequently called the CORESTA Unit (CU), wherein 1 CU=1 cm 3 /(min cm 2 kPa). Known cigarette papers exhibit an air permeability between 10 CU and 300 CU, wherein the range of 20 CU to 120 CU is most commonly used.
[0006] The air permeability can, for example, be determined in accordance with ISO 2965. According to ISO 2965, the volume of air flowing through a rectangular opening with a width of 10 mm and a length of 20 mm per unit time at a pressure difference of 1 kPa is determined and expressed in CU units. Alternatively, in accordance with ISO 2965, a rectangular opening with a width of 2 mm and a length of 15 mm can be used.
[0007] An assumption which very closely approximates to conventional cigarette papers is that the air-flow through the cigarette paper is proportional to the pressure difference in the range of pressure differences to which the cigarette paper on a cigarette during smoking is exposed. Hence a linear relationship exists between pressure difference and air-flow through the paper. The typical pressure difference between the inside and the outside of the cigarette during smoking is between 0 kPa and 1.0 kPa.
[0008] In Annex D.2 (ISO 2965:2009), ISO 2965 allows the non-linearity of the relationship between air-flow and pressure difference to be estimated. For this purpose, at least one measurement of the air-flow Q 1 at a pressure difference p 1 =1.0 kPa and one measurement of the air-flow Q 2 at a pressure difference of p 2 =0.25 kPa is made. The exponent k is calculated from both measured values in accordance with equation (D.6) in ISO 2965:2009 by
[0000]
k
=
log
Q
1
Q
2
log
p
1
p
2
[0009] This exponent k describes the non-linearity and is in the range of 0.5 to 1.0, whereby a value of 1.0 describes linear relationships. In this regard, conventional cigarette paper, as stated before, exhibits linear behavior and thus has a value for the exponent k of between 0.98 and 1.0.
[0010] Measurement devices that measure the air permeability in accordance with ISO 2965 are commercially available and in most cases also allow the exponent k to be determined. Consequently, here, whenever reference to a value of the exponent k is made, it should be understood that the value is calculated from a measurement at 1.0 kPa and a measurement at 0.25 kPa in accordance with ISO 2965, Annex D.2, with a measuring head with a rectangular opening of 2 mm by 15 mm.
[0011] Further technical requirements for the cigarette paper are related to the processability of the cigarette paper on the cigarette machine, for example basis weight, thickness, elongation at break and tensile strength. Additionally, there are further requirements related to the optical properties of the cigarette paper, for example, opacity and whiteness. Furthermore, there are extensive legal regulations for the ingredients allowed in cigarette paper.
[0012] But above all, for cigarette paper the influence on the taste of the cigarette plays a major role, as the cigarette is burnt together with the tobacco and the combustion products from the cigarette paper form part of the smoke. Hence, it is important that all modifications to the cigarette paper leave the cigarette paper chemically in an as natural state as possible, so that the components of the cigarette paper do not have a negative influence on the taste of the smoke.
[0013] At the same time, there is an interest in controlling the smoke yields of a cigarette by modification of the cigarette paper.
SUMMARY OF THE INVENTION
[0014] The invention is based on the objective of providing a cigarette paper that achieves higher dilution of the smoke compared to a conventional cigarette paper of approximately equal air permeability. The cigarette paper should in this regard deviate chemically and physically as little as possible from a conventional cigarette paper in order not to influence the taste and the smoke chemistry.
[0015] This objective is achieved by a cigarette paper according to claim 1 . The invention further applies to a cigarette manufactured from a cigarette paper according to the invention and a method of manufacturing a cigarette paper according to the invention.
[0016] Such a cigarette paper, according to the invention, is characterized in that it has an exponent k for the air permeability of ≦0.98, preferably ≦0.95 and especially preferably ≦0.93. For the lower limit of the exponent k in the context of this invention, k≧0.80, preferably, k≧0.85.
[0017] An exponent k of less than 1.0 means that the relationship between the pressure difference and the air-flow passing through the paper is non-linear. This implies that for two papers of equal air permeability—measured at 1 kPa in accordance with ISO 2965—but with different exponents, the paper with the smaller exponent allows a greater air-flow through the paper if the pressure difference is between 0 kPa and 1 kPa, but a smaller air-flow at pressure differences above 1 kPa. This relationship is illustrated in FIG. 1 .
[0018] As the pressure difference during smoking of a typical cigarette in the area of the cigarette paper is between 0 kPa and 1 kPa, a paper with the same air permeability but with a smaller exponent allows a greater flow of air into the cigarette and hence a greater dilution of the smoke and consequently a greater reduction in the harmful substances taken up by the smoker.
[0019] It should be noted that a non-linear relationship between the pressure difference and the air-flow, that is, a value for the exponent of significantly less than 1, also results for artificially perforated cigarette papers. The term “artificial perforation” should be understood to mean a perforation that is made in the finished cigarette paper and has to be distinguished from the “natural porosity” that results from the fibrous structure of a cigarette paper. The holes, which can, for example, be produced by electrostatic perforation, have a diameter between 30 μm and 100 μm. Using laser perforation, holes with a diameter between 100 μm and 500 μm can be produced. In contrast, a naturally porous cigarette paper has hardly any pores with a diameter≧10 μm. The present invention specifically does not relate to cigarette papers that feature an artificial perforation. An artificial perforation means an additional effort and can occasionally change the physical properties of the cigarette so much that the cigarette cannot be lit in a conventional manner.
[0020] In the case of the invention, the exponent k of the cigarette paper in accordance with the invention may also be sufficiently reduced over only a part of its surface rather than its entire surface. The said part should, however, be at least 30%, preferably at least 50% and especially preferably at least 70% of the total area.
[0021] In the context of the invention, a low value of the exponent k can be obtained by increasing the ratio of the number of large pores compared to that of smaller pores in comparison to conventional cigarette papers, but without resorting to artificial perforation.
[0022] In an advantageous embodiment, this is accomplished by coating or treating the cigarette paper on said part of its area with a material, especially a film-forming material, the amount of which, however, is comparatively small and does not exceed 2.0g/m 2 , preferably 1.5 g/m 2 . In this manner, the small pores can primarily be sealed. This reduces the air permeability, though only to a comparatively small extent, as the small pores contribute relatively much less to the air permeability than the small pores because of Hagen-Poiseuille's law. A certain decrease in the air permeability is inevitable due to sealing of the small pores, but this can in any case be compensated for by reduced refining of the pulp, which additionally is linked to corresponding energy savings.
[0023] It should be noted that coating cigarette papers with film-forming compositions in discrete areas is used in the prior art to provide a cigarette manufactured therefrom with self-extinguishing properties. However, for this, the amounts of material applied are substantially greater than in this embodiment of the invention. In the prior art, areas treated with film-forming compositions, which should provide self-extinguishing properties to a cigarette, typically have an air permeability of 0 to 10 CU. In contrast, the inventive cigarette paper, independently of the way in which the reduced exponent k in accordance with ISO 2965:2009 is obtained, has an air permeability in the corresponding part of its surface which is always at least 15 CU, preferably at least 20 CU and especially preferably at least 25 CU, because self-extinguishing is not the objective of the inventive cigarette paper. This, however, does not exclude the cigarette paper being additionally treated locally to further reduce the air permeability and to provide self-extinguishing properties to a cigarette manufactured from this paper.
[0024] For the treatment or coating of the paper, materials are used that preferably are contained in conventional cigarette papers, for example starch, starch derivatives, especially oxidized starch, cellulose derivatives, especially carboxy methyl cellulose, guar, pectin or polyvinyl alcohol. In addition, mixtures of two or more of these materials can be used.
[0025] In contrast, materials that substantially change the composition of the smoke are not wanted; rather, a dilution effect is the objective of the invention, which affects all substances in the smoke to approximately the same extent. Furthermore, materials for reduction of the exponent k that have a negative influence on the taste of the cigarette and therefore acceptance of a cigarette manufactured from this paper should be avoided. Preferably, the use of alginates for the treatment of the paper should be avoided.
[0026] A film-forming material can be applied in the form of a film-forming composition that comprises at least a liquid and a film-forming material. In the present specification, a material should be understood to be “film-forming” in the proper sense if its components are capable of forming an approximately closed film by mutual cross-linking. For the liquid, water is preferably chosen, but the use of organic solvents can also be considered. For the film-forming material, materials can be considered that form solutions or colloidal suspensions in this liquid, which is the case for the materials mentioned above.
[0027] Apart from “film-forming compositions” in their strictest sense, small amounts of a composition can be applied, however, which comprise a liquid and particles of sufficiently small size with which the small pores can be sealed efficiently, to thereby decrease the exponent k with a relatively small change in air permeability. As mentioned before, this small change in air permeability can be compensated for by reduced refining of the pulp. The advantage of adding at least a small amount of a film-forming material is that in this manner, the particles can be fixed better in the cigarette paper.
[0028] In a preferred embodiment, the exponent k is varied in said part of the surface, such that it varies along the length of cigarette which can be produced therefrom. Particularly, said part of the surface can have a first and a second part, of which the first part is located closer to the mouth end of the cigarette, on a cigarette which can be produced therefrom, than the second part, whereby the exponent k in the first part is lower than in the second part. An advantage of a lower exponent k in the area of the mouth end or the filter of the cigarette is that in this area, the pressure difference is typically about 0.5 kPa and the effect of the low exponent k is strongest.
[0029] In an advantageous embodiment, marks are provided on the cigarette paper, which are in register with said part of the surface. In this way, it can be ensured that during the production of cigarettes manufactured from papers with an exponent k that varies over the length, the treated area on the cigarette is always in approximately the desired position.
[0030] If the reduction of the exponent k is obtained, for example, by printing a film-forming composition, such register marks can be applied to the cigarette paper during the printing process. The aforementioned marks can be detected by corresponding control devices on the cigarette machine and cutting of the tobacco rod can be synchronized so that the treated area on the cigarette is always located in the same position.
[0031] Preferably, the basis weight of the cigarette paper is between 10 g/m 2 and 60 g/m 2 , especially preferably between 20 g/m 2 and 35 g/m 2 .
[0032] Preferably, the cigarette paper contains an inorganic mineral filler that is added to the paper in a fraction of 10% to 45% by weight. Preferably, the fraction is 20% to 45% by weight and especially preferably from 30% to 45%, as when the filler content is high, small pores are primarily formed and exponents k closer to 1 may be expected, so that the invention can be instigated more effectively. Preferred filler materials in this regard are calcium carbonate, magnesium oxide or aluminum hydroxide or combinations thereof.
[0033] Preferably, the cigarette paper can be equipped with burn additives that increase or reduce the smoldering speed of the paper. Preferably, the cigarette paper contains at least one burn additive, which can be one or more of the following salts: a citrate, especially a tri-sodium and/or tri-potassium citrate, a malate, a tartrate, an acetate, a nitrate, a succinate, a fumarate, a gluconate, a glycolate, a lactate, an oxylate, a salicylate, a α-hydroxy caprylate and/or a phosphate. To this end, the paper is, for example, impregnated with a solution or suspension of these burn additives in the size press, or the solution or suspension is applied to the surface of the paper in a film press.
[0034] The present invention further relates to a method for producing a cigarette paper according to one of the embodiments described above. In this respect, the cigarette paper may, for example, already have been selected such that a correspondingly low exponent k results by appropriate choice of the composition of the paper in combination with the manufacturing process. For example, by selecting the filler material or by selecting the particle size distribution of the filler material, it is advantageously possible to facilitate the formation of larger pores at as early as the paper production stage.
[0035] Alternatively, in the context of this invention, it is possible to initially produce a base paper, which still has an exponent k close to 1, and then treat at least a part of the surface of the base paper such that the exponent k is reduced to a value of k≦0.98, preferably k≦0.95 and especially preferably k≦0.93. This method, however, should be carried out such that the value of k does not decrease below a value of 0.80 and preferably not below 0.85, and that the air permeability is maintained at a value of at least 15 CU, preferably at least 20 CU and especially preferably at least 25 CU.
[0036] As mentioned above, this method can be carried out by applying an appropriate material, especially a film-forming material. To this end, the material can be applied, preferably in the form of a solution or a colloidal suspension, especially in a printing method such as gravure printing or flexographic printing, by spraying or by application in the size press or film press of a paper machine.
[0037] Alternatively, the cigarette paper can be embossed in said part of the surface, or compressed—for example between steel cylinders. During compression, small pores are also preferably sealed, whereupon the value of the exponent k decreases.
BRIEF DESCRIPTION OF THE FIGURES
[0038] FIG. 1 shows a schematic drawing of the profile of the air-flow through a cigarette paper as a function of the pressure difference for a cigarette paper with linear behavior (k=1) and two cigarette papers with non-linear behavior (k 2 <k 1 <1).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] The following examples of embodiments serve to illustrate the invention.
Comparative Example 1
[0040] A conventional, non-inventive cigarette paper with a basis weight of 25.0 g/m 2 , manufactured from wood pulp and with a filler material content of 30.2% by weight chalk and impregnated with 1% by weight tri-potassium citrate has a specified air permeability of 125 CU. The exponent k, as a mean value of 10 measurements carried out in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm, is 0.9981 with a standard deviation of the single value of 0.0038.
Comparative Example 2
[0041] A conventional, non-inventive cigarette paper with a basis weight of 28.0 g/m 2 , manufactured from wood pulp and with a filler material content of 3.7% by weight chalk and impregnated with 1% by weight tri-potassium citrate has a specified air permeability of 75 CU. The exponent k, as a mean value of 10 measurements carried out in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm, is 0.9968 with a standard deviation of the single value of 0.0066.
Comparative Example 3
[0042] A conventional, non-inventive cigarette paper with a basis weight of 25.5 g/m 2 , manufactured from flax pulp and with a filler material content of 24.8% by weight chalk and impregnated with 1.15% by weight tri-potassium citrate has a specified air permeability of 55 CU. The exponent k, as a mean value of 10 measurements carried out in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm, is 0.9972 with a standard deviation of the single value of 0.0061.
Comparative Example 4
[0043] A conventional, non-inventive cigarette paper with a basis weight of 25.5 g/m 2 , manufactured from wood pulp and with a filler material content of 27.5% by weight chalk and impregnated with 0.85% by weight of a 1:1 by weight mixture of tri-sodium and tri-potassium citrate has a specified air permeability of 19 CU. The exponent k, as a mean value of 10 measurements carried out in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm, is 0.9989 with a standard deviation of the single value of 0.0037.
[0044] Comparative Examples 1-4 show that conventional cigarette papers generally have an exponent k between 0.99 and 1.00 over the entire range of the technically preferred air permeability and independently of the choice of the pulp or the filler material content. In contrast to that are the inventive papers, which all have exponents k below this range.
[0045] In each of the following exemplary embodiments 1-6 a film-forming composition was applied to the cigarette paper with a laboratory printer from Erichsen, the K Printing Proofer model, serial number 87772. To achieve the inventive effect, the speed setting was set to the maximum, level 10, and also the doctor blade was set to the maximum contact pressure. In addition, a very high or the maximum possible (exemplary embodiment 4) contact pressure was selected for the impression roller. Experiments have shown that to carry out the invention, these extreme settings of the laboratory printer are important, inter alia. The printing plate had a screen ruling of 100 lines per inch.
Exemplary Embodiment 1
[0046] The entire surface of the cigarette paper of Comparative Example 2 was coated with a film-forming composition, specifically with an aqueous solution of 0.5% by weight of a carboxy methyl cellulose, Blanose® CMC 7MCF, using the laboratory printer. The paper was dried after coating and the applied amount was determined to be 1.04 g/m 2 by measurement of the basis weight in accordance with ISO 536 before and after coating. The air permeability and the exponent k were measured 10 times in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm, and the mean value was calculated. The mean value for the air permeability was 70.0 CU, the mean value for the exponent k was only 0.974 with a standard deviation of the single value of 0.0028.
Exemplary Embodiment 2
[0047] The entire surface of the cigarette paper of Comparative Example 2 was coated with a film-forming composition, specifically with an aqueous colloidal solution of 1.0% by weight of a cationic starch, Cationamyl®, using the laboratory printer. The paper was dried after coating and the applied amount was determined to be 1.57 g/m 2 by measurement of the basis weight in accordance with ISO 536 before and after coating. The air permeability and the exponent k were measured 10 times in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm and the mean value was calculated. The mean value for the air permeability was 53.7 CU, the mean value for the exponent k was only 0.972 with a standard deviation of the single value of 0.0026.
Exemplary Embodiment 3
[0048] The entire surface of the cigarette paper of Comparative Example 2 was coated with a film-forming composition, specifically with an aqueous solution of 0.5% by weight of a carboxy methyl cellulose, Blanose® CMC 7MCF and adding 5.0% by weight of chalk, using the laboratory printer. The paper was dried after coating and the applied amount was determined to be 1.60 g/m 2 by measurement of the basis weight in accordance with ISO 536 before and after coating. The air permeability and the exponent k were measured 10 times in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm and the mean value was calculated. The mean value for the air permeability was 46.8 CU, the mean value for the exponent was only 0.937 with a standard deviation of the single value of 0.0036.
Exemplary Embodiment 4
[0049] The entire surface of the cigarette paper of Comparative Example 2 was coated with a film-forming composition, specifically with an aqueous solution of 0.5% by weight of a carboxy methyl cellulose, Blanose® CMC 7MCF and an addition of 5.0% by weight chalk, using the laboratory printer. The paper was dried after coating and the applied amount was determined to be 1.46 g/m 2 by measurement of the basis weight in accordance with ISO 536 before and after coating. The air permeability and the exponent k were measured 10 times in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm and the mean value was calculated. The mean value for the air permeability was 48.7 CU, the mean value for the exponent k was only 0.898 with a standard deviation of the single value of 0.0052.
Exemplary Embodiment 5
[0050] The cigarette paper of Comparative Example 1 was treated according to the method of exemplary embodiment 2. The applied amount was determined to be 1.20 g/m 2 by measurement of the basis weight in accordance with ISO 536 before and after coating. The air permeability and the exponent k were measured 10 times in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm and the mean value was calculated. The mean value for the air permeability was 82.5 CU, the mean value for the exponent was only 0.961 with a standard deviation of the single value of 0.0043.
Exemplary Embodiment 6
[0051] The cigarette paper of Comparative Example 1 was treated according to the method of exemplary embodiment 4. The applied amount was determined to 1.56 g/m 2 by measurement of the basis weight in accordance with ISO 536 before and after coating. The air permeability and the exponent k were measured 10 times in accordance with ISO 2965:2009 with a Borgwaldt A10 instrument and a measuring head with a rectangular opening of 2 mm by 15 mm and the mean value was calculated. The mean value for the air permeability was 82.5 CU, the mean value for the exponent k was only 0.826 with a standard deviation of the single value of 0.0064.
[0052] The above exemplary embodiments show that the exponent k can be decreased in the manner described to values far below 0.98 without dramatically reducing the air permeability in accordance with ISO 2965. The observed reduction in air permeability in accordance with ISO 2965 can be compensated for by an increased initial air permeability of the base paper, for example, by reduced refining. The film-forming compositions used do not lead to noticeable adverse effects on the taste of the smoke compared with the base paper and do not result in a significant chemical change of the smoke; instead—at pressure differences below 1.0 kPa, which usually occur during normal smoking—solely in an advantageous dilution compared with a conventional cigarette paper with the same air permeability in accordance with ISO 2965 and an exponent k close to 1. | A cigarette paper is shown which has a surface, at least a part of the surface having the properties of:
no artificial perforation an air permeability of at least 15 CU, and for an exponent k measured with a measuring head with a rectangular opening of 2 mm by 15 mm in accordance with ISO 2965:2009, which is defined as:
k
=
log
Q
1
Q
2
log
p
1
p
2
where:
Q 1 represents air-flow through the paper at a pressure difference p 1 =1.00 kPa,
Q 2 represents air-flow through the paper at a pressure difference p 2 =0.25 kPa, and wherein k≦0.98 and k≧0.8. | 3 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to tent support framework systems and, in particular, to a multi-sectional tubular self-supporting framework assembly wherein a plurality of tubular pole pieces or sections are secured together with appropriate radially adjustable hinge couplers, in-line clevis/saddle couplers and “T or collar” couplers that longitudinally and transversely interconnect the tubular pole pieces to define a desired support framework.
[0002] With the increasing popularity of outdoor activities, a resurgence of interest has occurred in the camping industry. A variety of designs for stable, collapsible frame tents have evolved to meet this demand. Such tents are designed to meet the needs of a variety of users from backpackers, to weekend campers, who camp from their vehicle, to outfitted camps that are established in remote sites from horseback or four-wheeled vehicles.
[0003] Many tent support frames utilize a number of small diameter (i.e. less than ½ inch) poles constructed of fiberglass, aluminum or high strength materials. The poles frequently contain elastic shock cords and typically mount through fabric loops or to sleeves or clips secured to the tent fabric. With the assembly of the poles to define a framework, a fabric tent is draped over the frame and held taught with suitable fasteners. Some small tents provide self-contained support poles, which are permanently retained to the tent fabric.
[0004] Other or so-called “sheep herder or wall” tents have also shared in the resurgence of interest in camping. Historically, such tents were used by nomadic sheep herders, although wall tents are used to bivouac military and other personnel living and working from remote temporary sites. Tents offering comparable functionality are frequently used by recreating families and groups of hunters and fishermen for multi-day, base camps. The tents provide relatively large open floor living spaces that are heated with wood or gas stoves and contain various camp support furnishings in a weather protected setting. The fabric and other coverings for tents of this type however are relatively heavy and require a strong framework. Preferably the framework assembles with minimal effort and parts and provides multiple wind and snow stabilizing supports. Preferably too the support framework is modular and able to accommodate different arrangements of the support pieces.
[0005] Traditionally, the support framework for wall tents was mounted external to the fabric. More recently, internal frame support systems have been developed to more efficiently perform the same function with re-usable, lightweight tubular poles. These internal frame systems can also be used with one or more sections of tarpaulins to construct temporary weatherproof shelters such as for team sporting events or outdoor display/sale stalls for crafts, vegetables etc.
[0006] One such support system is described at U.S. Pat. No. 5,255,698. Rigid sleeve couplers are provided which retain pole sections that can be rotated in the sleeves. Although the '698 system adequately supports a tent and is susceptible to volume production with modular couplers, the couplers do not readily accommodate cabin style tents.
[0007] Another support system is disclosed at U.S. Pat. No. 5,069,238. This assembly provides hinged couplers which contain end support poles at a defined orientation to each other. Guy ropes, in turn, support the end frames and an overlying fabric cover. The couplers support the poles only in a single plane and are not able to contain longitudinal support poles, which are desired in a self-supporting framework.
[0008] Other couplers used in self-supporting frames are known which provide multiple sleeve segments that are welded at defined orientations to each other. A number of different types of couplers specific to each joint type are thus required to configure a desired framework. Correspondingly, it is necessary to stock a large variety of parts designed for each specific joint location, for example, inside/outside corners with defined angular orientations, straight couplers, T-couplers for horizontal ridge pole sections and associated vertical supports etc. Interconnecting pole pieces mount in the sleeves at specific structural locations and tarp(s) or a sewn contoured tent of a mating shape are fitted over the tubular frame skeleton.
[0009] To overcome the necessity of inventorying multiple parts and other logistics problems, a radially adjustable coupler was developed by applicant and is shown at U.S. Pat. No. 5,255,698. Such couplers are used in a variety of tent constructions including those shown in U.S. Pat. No. 6,273,114.
[0010] Couplers of the '698 type are used in frame systems constructed with several new coupler pieces of the present invention to facilitate construction of improved modular frameworks. The subject couplers were developed to provide flexibility and enhance the construction of wall-type tents and shelters.
[0011] The new improved couplers of the present invention were developed to enhance a user's options to tailor design a user's preferred tent support framework. The present invention provides for novel in-line clevis/saddle couplers that pivotally support pinned tubular pieces at any desired angular orientation between the ground or another coupler secured to an opposite end of the tubular section. Also disclosed is an “T or collar” coupler that can be used as an end fitting and that orthogonally pivots about a transecting interconnected pole piece. Hinged couplers providing adjustable and locked splay angles are also disclosed.
[0012] The improved couplers can be cast from aluminum, stainless steel or other suitable materials. The couplers are constructed to combine with interconnected tubular support pole pieces of 1 to 1½-inch diameter to form a strong, wind resistant support system for a canvas cover.
[0013] The present clevis/saddle, T/collar and hinge couplers are cast from appropriate metals and materials (e.g. aluminum, stainless steel etc.) to accommodate supported loads. The bores of the sleeves, collars and clevis saddles can be sized as desired to contain the coupled tubular pole pieces that radiate from the couplers. The poles can either be cut-to-length or can be mounted to telescope.
SUMMARY OF THE INVENTION
[0014] It is a primary object of the invention to provide a modularly configured tent support framework.
[0015] It is a further object of the invention to provide a framework including couplers capable of supporting a number of pole sections or pieces in multiple, interconnected planes.
[0016] It is a further object of the invention to provide a coupler accommodating a range of splay angles between interconnected poles, typically in truss-type gusset or cross bracing configurations.
[0017] It is a further object of the invention to provide a sleeve coupler adapted to coaxially receive one or more pole pieces inserted in a bore of a sleeve piece and pivotally support another pole piece from a depending clevis or saddle piece that transversely projects from the clevis/saddle of the sleeve piece.
[0018] It is a further object of the invention to provide a collared T-connection between transecting pole pieces wherein a 360° range of splay angles is possible between the sleeve coupled pole piece relative to a transecting interconnected pole piece coupled to a collar or eyelet end.
[0019] It is a further object of the invention to provide a T or collar coupler having a tubular sleeve body that receives a tubular pole piece and an eyelet or collar end having one or more circular appendages including a bore sized to mount over and pivot about a transecting pole piece.
[0020] It is a further object of the invention to provide a hinge coupler having multiple hinge arms that interconnect with each other at a hinge pole piece inserted through overlapped collar ends of the hinge coupler.
[0021] It is a further object of the invention to provide a hinge coupler having hinged sleeve pieces or sleeve bodies at one end that receive tubular splay pole pieces and bored eyelet or collar ends at an opposite end that receive a hinge pole piece and wherein arcuate wing arms extend from the sleeve bodies to overlap and fasten to each other and maintain a preferred splayed, angular orientation between the splay pole pieces that extend from the hinged sleeve pieces.
[0022] It is a further object of the invention to provide a hinge coupler having serrated, overlapping wing arms that contain overlapping slots or apertures that align and accept a support a fastener used to draw the arms together and secure the splayed pole pieces at a preferred angle.
[0023] The foregoing objects, advantages and distinctions of the invention are obtained in a modular tent support framework. The framework includes a number of tubular pole pieces that radiate from a number of in-line clevis/saddle couplers, collared T-couplers and/or radially adjustable hinge couplers. The system or collection of framework couplers assemble to form any desired support skeleton for an overlying fabric cover. The pole pieces can be cut to size or can telescope from each other. The pole pieces interconnect to selected couplers and are arrange able to provide vertical and longitudinal support for the fabric cover. Other selected couplers provide support bracing between adjacent pole pieces. The system of couplers is particularly adaptable to wall tents or other temporary outdoor shelters.
[0024] A sleeve body of the in-line clevis or saddle couplers couple to one or more coaxially aligned pole pieces and pivotally support another pole piece at an included depending clevis or saddle piece. A single or a pair of coaxially aligned pole pieces butted to each other mount in the sleeve body. Another pole piece is pivotally supported via a through mounted pivot fastener secured through the projecting clevis or saddle and projecting pole piece. The tubular sleeve body can be adapted to slide over one or more pole pieces. One or more set screw type fasteners can extend through the sleeve body to retain the coupled pole piece(s).
[0025] The clevis/saddle couplers particularly facilitate the construction of gussets or trusses to span corner connections or cross bracing between displaced pole pieces. Vertical support poles may also depend from the clevis or saddle piece when the clevis/saddle couplers are inserted into relatively long horizontal span (e.g. vertical ridge pole support). A variety other possible pole mountings are also possible.
[0026] The “T or collar” couplers provide a tubular sleeve portion and a double-eyelet or collar end piece. The collar or eyelet end piece allows a first pole piece to be mounted through a bore of the collar end. The collar coupler can rotate 360° about the first pole piece to any desired right angular orientation. A second pole piece mounts inside the tubular sleeve portion and extends at right angles to the transecting first pole piece. The collar couplers essentially provide a T-coupling and can be used as a ridge pole brace support or as a cross brace between horizontal tubular pole pieces or as a vertical ridge pole support that rests on the ground, among other uses.
[0027] The hinge couplers have interlocking hinged sleeve arms that couple together in the fashion of a hinge and collectively pivot orthogonally about a supported hinge pole piece (e.g. ridge pole section). The hinge pole piece mounts through aligned bores of collar ends of the hinge arms. Separate pole pieces coaxially extend from the bores of tubular sleeve pieces that extend from an opposite end of the arms at a suitable splay angle established upon fastening overlapping arcuate hinge, web or wing arms that project from the sleeve pieces with lynch pins or other suitable fasteners.
[0028] Each hinge, web or wing arm arcuately radiates from a sidewall of each sleeve piece and is aligned to overlap in parallel alignment to a mating hinge arm of the interconnected hinged sleeve arm. The overlapping arcuate wing arms include serrated interlocking surfaces. Upon inserting a pivot or hinge pole section through the bores of the overlapped closed eyelet-type end collars at each hinged sleeve arm and drawing and fastening the overlapping wing arms together with suitable fasteners, the splayed pole pieces extending from each sleeve piece provides a stable vertical support for the interconnected horizontal pole pieces (e.g. ridge pole).
[0029] With the aid of the several couplers a variety other tent framework pole mountings can be established as desired. Still other objects, advantages and distinctions of the invention are described at the following description with respect to the appended drawings. Various considered modifications and improvements are described as appropriate. The described couplers may be used alone or be combined in a variety of combinations to define any desired support framework. The description should therefore not be literally construed in limitation of the invention. Rather, the invention should be interpreted within the scope of the further appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a perspective drawing shown in partial cutaway to a typical walled cabin-style tent and particularly to an included support framework having a number of novel in-line clevis/saddle couplers, T/collar couplers and hinge couplers arrayed in a variety of actual and possible orientations.
[0031] FIG. 2 is a perspective drawing showing several in-line clevis/saddle couplers, a T/collar couplers and a hinge coupler such as mounted at one end of the framework of FIG. 1 .
[0032] FIG. 3 is a perspective drawing showing an enlarged view of the in-line clevis/saddle coupler detached from typically associated pole pieces shown in dashed line.
[0033] FIG. 4 is a perspective drawing showing an enlarged view of the T/collar coupler detached from typically associated pole pieces shown in dashed line.
[0034] FIG. 5 is a perspective drawing showing an enlarged view of the T/collar coupler of FIG. 4 rotate to expose the relationship of the collar end piece to a transecting pole piece about which the coupler can be rotated over a range of 360°.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] Referring to FIG. 1 , a perspective drawing is shown to a typical self-supported wall tent 2 . The tent 2 includes a support framework 4 that supports a fabric cover 6 sewn to provide a pair of end walls 8 (only one of which is shown), side walls 10 , and splayed ceiling walls 12 .
[0036] The cover 6 is constructed from a suitable grade of canvas or other waterproof material to resist wind, rain and snow. Depending upon the tent size, a number of fabric panels are sewn together to form the walls 8 and 10 and ceiling 12 . A chimney 14 is mounted through a fireproof panel 16 . Door access flaps with closure fasteners (not shown) are provided at one or both end walls 8 or can also be provided at the side walls 10 . External tie down straps 18 are provided as required to stabilize the tent 2 . Windows 20 and cover flaps 22 (shown in partial cutaway) may also be provided. Although one wall tent construction is shown, it is to be appreciated a variety of other shapes, sizes and arrangements of covers 6 can be fitted to a mating framework 4 erected to a complementary shape. The organization and features of each cover 6 can be varied to particular user needs.
[0037] The support framework 4 is correspondingly erected with a suitable number and types of interconnected pole sections and couplers. The framework 4 is particularly erected with a variety of coupler types discussed in detail below to define a desired arrangement of the pole sections adapted to the weight and wind loading of the tent 2 .
[0038] The framework 4 is constructed of a number of tubular pole sections 30 that are fitted to a number of adjustable and/or pivoting support couplers. The framework particularly supports a number of adjustable hinge couplers 32 , in-line clevis/saddle couplers 34 and T/collar couplers 36 . Each of the couplers 32 , 34 and 36 pivotally supports at least one associated pole section 30 as discussed below. The number and length of pole sections 30 required at the framework 4 depends upon the size of the tent 2 , cover shape and the location of the couplers 32 , 34 and 36 at the framework 4 .
[0039] The couplers 32 , 34 and 36 are constructed to support pole sections 30 of a nominal 1 to 2-inch diameter, although are adaptable with bushings or scaling to any diameter pipe, conduit etc. The pole pieces 30 are typically cut from tubular steel conduit but can be cut from aluminum, plastic or any other desired tubular stock. A variety of other solid and hollow pole stock materials of different cross sectional shapes may also be used to equal advantage to form the pole pieces 30 .
[0040] Each hinge coupler 32 supports three pole sections 30 that extend in two orthogonal planes. Each hinge coupler 32 is constructed to provide a pair of interlocking hinge arms 40 . The hinge arms 40 are interconnected with a pole piece 30 that is mounted through aligned bores 42 of interleaved circular eyelets or collars 44 that extend from an end of a tubular sleeve body 46 . Arcuate hinge, webs or wing arms 48 project from the sidewalls of the sleeve bodies 46 and overlap along mating serrated surfaces 50 . Fasteners 52 mounted through overlapped and aligned holes or slots in the wing arms 48 draw the serrated surfaces 50 together and lock the relative splay angle “A” between the sleeve bodies 46 and pole sections 30 that extend from the sleeve bodies 46 .
[0041] Several hinge couplers 32 are used in the depicted framework 2 at end wall and center support assemblies 60 and 62 . The couplers 32 are particularly mounted at the framework peak to a longitudinal ridge pole assembly 63 to support the coaxially arranged longitudinal pole sections 30 . Rafter-type pole section sub-assemblies 64 project at a desired splay angle from the peak hinge couplers 32 and couple to vertical ground support pole sub-assemblies 66 that transition into ground contact. The spacing between the vertical assemblies 66 is determined from the adjusted splay angle A established at the peak hinge coupler 32 upon fastening the overlapped arcuate hinge arms 48 together with suitable bolt/nut or lynch pin fasteners 50 .
[0042] The hinge arms 48 of each coupler 32 are constructed to interlock with one another upon aligning the collar bores 42 of the interleaved end collars 44 and mounting one or more pole sections 30 to the aligned bores 42 . The bores 42 are sized to circumscribe the pole section 30 which acts as a pivot or hinge pin for the hinge coupler 32 and allows the hinge arms 46 to rotate relative to each other to define a desired splay angle “A”. A single pole 30 may terminate at the interleaved bores 42 , as in the case of an end wall assemblies 60 as shown at FIG. 1 . Alternatively, when a coupler 32 is positioned along an intermediate section of a pole 30 as at the center support assembly 62 , butted ends of mating pole sections 30 can be mounted in the aligned bores 42 of the conjoined collars 44 .
[0043] The relative angular orientation of the pole sub-assemblies 64 and 66 is again maintained via the serrated interlocked surfaces 50 . The hinge arms 48 of the presently preferred couplers 32 arcuately extend from the sleeve bodies 44 and overlap over a range of rotation on the order of 30° to 60° degrees. The hinge arms 48 can be secured to each other in a variety of fashions with a variety of fastener types 52 . The hinge arms 48 presently include several apertures (e.g. holes, slots) that overlap at several defined splay angles “A”. The fasteners 52 mount through the aligned apertures to fix the splay angle A.
[0044] Hinge arms 48 of differing shapes can be constructed that overlap over greater or lesser, defined ranges. Collectively, the splayed pole end wall and center support assemblies 60 and 62 and rafter and vertical support sub-assemblies 64 and 66 provide a stable vertical support at the ends and center of the interconnected horizontal ridge pole assembly 63 and included coaxially aligned pole sections 30 . Each coupler 32 is thereby able to support multiple intersecting planar walls of the tent cover 6 in a variety of orientations and some of which are depicted in FIG. 1 .
[0045] The hinge couplers 32 , in-line clevis/saddle couplers 34 and T/collar couplers 36 are constructed of die cast metal such as aluminum or stainless steel. The hinge couplers 32 , 34 and 36 can be formed from a variety of other materials, such as fiber impregnated plastic etc. provided the material is able to withstand the loading and environmental conditions.
[0046] The end collars 44 and/or sleeve bodies 46 can also include setscrew-type fasteners 52 to retain the collars 44 and sleeve bodies 46 to the interconnected pole pieces 30 . Set screws, lynch pins or other fasteners 52 can be adapted to each hinge coupler 32 to achieve such ends. Preferably the fasteners 52 are located to prevent abrasive contact with the tent cover 6 .
[0047] FIGS. 2 and 3 depict detailed views to the in-line clevis/saddle coupler 34 . The coupler 34 includes a tubular sleeve body 70 having a longitudinal bore 72 . A clevis or saddle piece 74 having parallel flange arms or walls 76 projects from the sleeve body 70 and each arm includes an opposed aperture 78 . The displaced walls 76 are separated sufficiently to receive the end of a pole section 30 . Upon aligning the apertures 78 with apertures 80 at a pole section 30 and affixing a suitable pivot fastener 82 (e.g. lynch pin 84 and clip 86 ) through the aligned apertures 78 and 80 , the attached pole piece 30 can pivot over a range of 180° from the clevis/saddle piece 74 relative to the sleeve body 70 . Non-pivoting pole sections 30 are secured to the sleeve body 70 with other fasteners 82 aligned to-apertures 78 formed through the side walls of the sleeve body 70
[0048] Advantageously, the in-line clevis/saddle couplers 34 are adapted to the framework 4 to facilitate a variety of support and bracing connections. As depicted in FIGS. 1 and 2 exemplary sub-assembly mountings of the clevis/saddle coupler are shown. FIG. 2 depicts three clevis/saddle couplers 34 that support a truss brace pole sub-assembly 90 and a cross brace pole sub-assembly 92 .
[0049] FIG. 1 also depicts vertical brace support pole sub-assemblies 94 , longitudinal brace pole sub-assemblies 96 and gusset brace pole sub-assemblies 98 and 100 that extend from the center framework assembly 62 and the end wall framework assembly 60 . The vertical brace assembly 94 can extend to the ground or an adjoining cross brace or longitudinal brace sub-assembly 92 or 96 The longitudinal brace support pole sub-assemblies 96 stabilize the sidewalls in a similar fashion to the cross brace sub-assembly 92 and limit the bowing of the side walls 10 from heavy winds
[0050] The truss, cross, vertical and gusset brace sub-assemblies 90 , 92 , 94 , 98 and 100 stabilize the interconnected ridge pole assembly 63 and end wall assemblies 60 . The depending pole sections 30 of the vertical and gusset support pole sub-assemblies 94 and 98 are set into the ground to provide additional support for the tie down straps 18 . The gusset pole sub-assemblies 98 can be set at any desired angle relative to the side wall portions of the framework 4 of FIG. 1 .
[0051] FIGS. 4 and 5 depict detailed views to the “T” or collar coupler 36 . The T/collar coupler 36 includes a tubular sleeve body 110 having a longitudinal bore 112 . An end collar 114 projects from the end of the sleeve body 110 and includes a pair of projecting collar arms 116 having opposed bores 118 . The collar arms 116 are displaced sufficiently to spread support forces over a larger surface area of one or more interconnected pole sections 30 .
[0052] The displacement of the collar arms 116 also permits two, butted pole sections 30 to mount within the end collar arms 116 . Upon aligning and butting the pole sections 30 together in the end collar 114 , set screws 120 (shown in dashed line) or other fasteners (e.g. hose clamp) can be tightened to secure the established relative orientation of the T/collar coupler 36 to the interconnected pole sections 30 . Alternatively, the end collar 114 can be allowed to pivot about the orthogonally mounted pole section 30 mounted through the end collar 114 . One or more tubular bushings 122 can be mounted between the collar arms 116 and pole section 30 to prevent abrasion and facilitate any desired pivot action. In lieu of set screws a clamping band fastener 120 can be mounted to the transecting pole section 30 between the collar arms 116 to prevent rotation of the T/collar coupler 36 .
[0053] As noted at FIGS. 1 and 2 , the T/collar couplers 36 are used in the truss brace sub-assembly 90 and vertical support sub-assembly 94 at the side wall 10 . Depending upon any desired mounting and when a more rigid fastening is desired, the T/collar couplers 36 can be used instead of a clevis/saddle coupler 34 . Lynch pin fasteners 82 mount through apertures 78 to secure the T/collar couplers 36 to a pole section 30 fitted to the bore 112 .
[0054] While the invention has been described with respect to a presently preferred and considered alternative assemblies and sub-assemblies and considered improvements, modifications and/or alternatives thereto, still other assemblies and arrangements may be suggested to those skilled in the art. It is also to be appreciated that the features of the foregoing framework assemblies can be arranged in different combinations. The foregoing description should therefore be construed to include all those embodiments within the spirit and scope of the following claims. | A collapsible, modularly constructed, self-supporting tent support framework. The framework includes a number of support poles that interconnect at hinge, clevis/saddle and T/collar couplers. The couplers retain the pole sections at preferred angular orientations in multiple planes to support an overlying fabric cove. Each hinged coupler includes a pair of hinge pieces having a tubular sleeve body, an end collar that interleaves with the other hinge piece at a transecting pivot pole and a serrated, arcuately projecting wing arm having transverse bores that overlap and fasten together to define a desired splay angle. Each clevis/saddle coupler includes a tubular sleeve body and a depending clevis or saddle to pivotally secure a pole section. Each T/collar coupler includes a tubular sleeve body and end collars to pivotally mount to a transecting pole section. The pole pieces couple to the sleeve bodies, collared ends, and clevis/saddles of the framework couplers. | 4 |
BACKGROUND
[0001] The present invention relates to mortise locks and to doors with a lock at the top and/or bottom of the door.
SUMMARY
[0002] The invention provides a mortise lock comprising a case having opposite inner and outer sides which are horizontally spaced when the mortise lock is mounted on a door, a latchbolt supported by the case for movement between extended and refracted positions, the latchbolt extending from the outer side of the case, an element configured to be operably connected to a latch adjacent a top or a bottom of the door, the element being movably supported by the case and partially extending from the inner side of the case, and a latchbolt bar movably supported by the case, the latchbolt bar having an outer end operably connected to the latchbolt for moving the latchbolt between the extended and retracted positions, and the latchbolt bar having an inner end operably connected to the element for moving the element when the latchbolt bar moves the latchbolt.
[0003] The invention also provides a mortise lock comprising a case having opposite inner and outer sides which are horizontally spaced when the mortise lock is mounted on a door, a latchbolt supported by the case for movement between extended and refracted positions, the latchbolt moving horizontally between the extended and retracted positions when the mortise lock is mounted on the door, and the latchbolt extending from the outer side of the case, an element mounted on the case for pivotal movement about an axis which is horizontal and perpendicular to a vertical plane defined by a direction of movement of the latchbolt when the mortise lock is mounted on the door, the element partially extending from the inner side of the case, the element including an element surface outside of the case, the element surface moving vertically when the mortise lock is mounted on the door and when the latchbolt moves to the retracted position, a latchbolt bar movably supported by the case, the latchbolt bar having an outer end operably connected to the latchbolt for moving the latchbolt between the extended and retracted positions, the latchbolt bar moving along a horizontal line beneath the axis when the mortise lock is mounted on the door, and the latchbolt bar having an inner end operably connected to the element for moving the element when the latchbolt bar moves the latchbolt, and a rod which is entirely outside of the case and is configured to be operably connected to a latch adjacent a top or a bottom of the door, which extends vertically when the mortise lock is mounted on the door, and which has therein a recess into which the element extends, the recess being at least partially defined by a rod surface, the rod surface being engaged by the element surface and the rod moving in response to movement of the element.
[0004] The invention also provides a method of operating a latch mounted adjacent a top or a bottom of a door, the method comprising providing the door with an internal rod operably connected to the latch, thereafter mounting on the door a mortise lock including a case, a latchbolt supported by the case for movement between extended and retracted positions, and a manually movable member operably connected to the latchbolt for moving the latchbolt between the extended and retracted positions, and operating the latch via the rod in response to movement of the latchbolt.
[0005] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of a lock assembly embodying the invention.
[0007] FIG. 2 is an enlarged, exploded perspective view of the upper latch.
[0008] FIG. 3 is an enlarged, exploded perspective view of the lower latch.
[0009] FIG. 4 is an enlarged elevational view, partially in section, of the mortise lock with the latchbolt in its extended position.
[0010] FIG. 5 is an enlarged elevational view, partially in section, of the mortise lock with the latchbolt in its retracted position.
[0011] FIG. 6 is a further enlarged view of the lifter.
[0012] FIG. 7 is a view similar to FIG. 4 showing an alternative embodiment of the invention.
[0013] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
DETAILED DESCRIPTION
[0014] FIG. 1 shows a lock assembly 10 mounted on a door 14 . The door is mounted in a door frame 18 and has a top 22 and a bottom 26 . The lock assembly 10 comprises a mortise lock 34 mounted on the door, an upper latch 38 mounted adjacent the top 22 of the door, and a lower latch 42 mounted adjacent the bottom 26 of the door.
[0015] The mortise lock 34 is best shown in FIGS. 4 and 5 . Some elements of the lock not related to the invention are not shown. The mortise lock 34 includes a chassis case 46 and a latchbolt 50 supported by the case 46 for movement between an extended position ( FIG. 4 ) and a retracted position ( FIG. 5 ). The mortise lock 34 also includes a latchbolt bar 54 operably connected to the latchbolt 50 for moving the latchbolt between the extended and retracted positions. The latchbolt bar can either be a separate piece connected to the latchbolt in any suitable manner, or the latchbolt bar and the latchbolt can be unitary. The latchbolt bar 54 has a generally horizontal longitudinal axis 58 and moves along the axis. The mortise lock 34 also includes a spindle 62 that extends generally horizontally and generally perpendicular to the plane of the door. Interior and exterior manually movable members, such as handles or levers, are connected to the opposite ends of the spindle 62 . One lever 66 is shown in FIG. 1 . Other types of manually movable members, such as door knobs, can be used. A crank member 70 operably connects the spindle 62 to the latchbolt bar 54 for causing translational movement of the latchbolt bar 54 in response to pivotal movement of the spindle. The mortise lock 34 as thus far described is conventional and need not be described in greater detail. An example of such a mortise lock is the Schlage L9000 Series Mortise Lock, which is known in the art. It should be understood that the invention is applicable to other types of mortise locks and to locks made by other manufacturers.
[0016] The lock assembly 10 also includes a vertical rod 74 inside the door 14 . The upper end of the rod 74 is operably connected to the upper latch 38 , which is best shown in FIG. 2 . The upper latch 38 is a soffit latch and ratchet release. Part of the upper latch 38 is mounted in the door, and part is mounted in the door frame. Upward movement of the rod 74 opens or releases the upper latch 38 . Also, the rod 74 is held in its upper position until the door is closed, at which time the rod 74 is released and is allowed to drop back to its original position. The upper latch 38 will not otherwise be described in detail. The invention is applicable to any upper latch that can be actuated by movement of a vertical rod. The lower end of the rod 74 is operably connected to the lower latch. Actually, in the construction shown in FIG. 3 , the lower end of the rod 74 is part of the lower latch 42 . The lower end of the rod 74 extends into a recess in the floor when the lower latch 42 is closed or engaged, and the lower end of the rod 74 is retracted from the recess when the lower latch 42 is open or disengaged. Thus, upward movement of the rod 74 releases the lower latch 42 , and downward movement of the rod 74 engages the lower latch 42 . The lower latch will not otherwise be described in detail. The invention is applicable to any lower latch that can be actuated by movement of a vertical rod. The vertical rod 74 and the latches 38 and 42 as thus far described are also conventional. An example of such a vertical rod and two-point latch is the Von Duprin 237, which is known in the art. It should be understood that the invention is applicable to other types of rods and latches and to those made by other manufacturers.
[0017] In the illustrated construction, as best shown in FIGS. 4 and 5 , the rod 74 includes upper and lower sections 78 and 82 , respectively, connected by a middle section 86 . The upper end of the lower section 82 extends into a recess in the middle section 86 and is secured to the middle section 86 by a pin 94 . The lower end of the upper section 78 is threaded into a recess in the middle section 86 . Upward movement of the middle section 86 pulls the lower section 82 upward and pushes the upper section 78 upward. The middle section 86 has therein a recess 90 opening toward the case 46 of the mortise lock. The recess 90 is partially defined by a horizontal, downwardly-facing rod surface 98 .
[0018] Movement of the rod 74 is controlled by an auxiliary mechanism in the mortise lock 34 . The auxiliary mechanism includes (see FIGS. 4-6 ) an element or cam member or lifter 100 pivotally mounted inside the case 46 , with the lifter 100 partially extending from the inner side or rear of the case. More particularly, the inner side of the case 46 has therein an opening 104 through which the lifter 100 extends. The lifter 100 is pivotable relative to the case about a horizontal axis 108 that is perpendicular to the plane of the door or perpendicular to the vertical plane defined by the direction of movement of the latchbolt 50 , or defined by the longitudinal axis 58 of the latchbolt bar 54 . The axis 108 is above the latchbolt bar 54 , such that the latchbolt bar moves along a line (axis 58 ) beneath the axis 108 of the lifter 100 . In the illustrated construction, the lifter 100 hangs from and pivots about a pin or post 112 that is mounted on the chassis case 46 and that extends along the axis 108 . The lifter 100 is pivotable between a non-actuated position shown in FIGS. 4 and 6 and an actuated position shown in FIG. 5 .
[0019] The lifter 100 has an outer or left side and an inner or right side. The inner side of the lifter 100 includes (see FIG. 6 ) an element surface or lifter surface 116 outside of the case 46 . The surface 116 extends horizontally when the lifter 100 is in the non-actuated position. The surface 116 moves vertically, and specifically upward, when the lifter 100 moves to the actuated position. The rod surface 98 rests on the lifter surface 116 such that the rod 74 moves upward when the lifter surface 116 moves upward. Thus, movement of the lifter 100 from the non-actuated position to the actuated position moves the rod 74 upward and thereby, as described above, releases the upper and lower latches. Because pivotal movement of the lifter 100 may also exert a horizontal force (to the right) on the rod 74 , the door includes a wall 118 limiting movement of the rod 74 to the right or away from the case 46 .
[0020] The lifter 100 also includes an engagement surface 120 that engages the outer surface of the case 46 . Such engagement limits clockwise movement of the lifter 100 and defines the non-actuated position of the lifter 100 . The surface 120 extends vertically when the lifter 100 is in the non-actuated position. In the illustrated construction, the lifter 100 has therein an arcuate slot 124 that provides clearance for a pin 128 that is fixed to the case 46 and that performs a function unrelated to the invention. The slot 124 would not be necessary with some mortise locks.
[0021] As shown in FIG. 6 , a surface 132 on the outer or left side of the lifter 100 is engaged by the inner or tail end of the latchbolt bar 54 . The surface 132 extends vertically when the lifter is in its non-actuated position. In this way the latchbolt bar 54 is operably connected to the lifter 100 such that movement of the latchbolt bar 54 to the right (when the latchbolt 50 moves to the retracted position) moves the lifter 100 from its non-actuated position to its actuated position. While in the illustrated construction the latchbolt bar 54 only pushes against, and is not otherwise connected to, the lifter 100 , other types of connections are possible, so long as the lifter 100 pivots in response to movement of the latchbolt bar 54 . When the latchbolt bar 54 moves to the left as the latchbolt moves to its extended position, the lifter 100 returns to its non-actuated position, which allows the rod 74 to drop when it is released by the upper latch 38 when the door closes.
[0022] Because the mortise lock 34 engages the rod 74 from the rear or inner side of the case 46 , and the rod is entirely outside of the case, the mortise lock can be installed or removed from a door while the door is in place. Preferably, the door is provided with the rod 74 operably connected to the portion of the upper latch 38 that is in the door. The door can be mounted on the door frame, and then the mortise lock 34 is mounted on the door. When the lock 34 is mounted on the door, the lifter 100 is inserted into the recess 90 so that the lifter 100 engages the rod 74 . The lock 34 is then operated as described above. Because the rod 74 does not pass through the case 46 , the lock does not have to be installed in the door prior to the rod, or prior to hanging the door.
[0023] FIG. 7 shows an alternative lock assembly 200 . Except as described below, the lock assembly 200 is substantially identical to the lock assembly 10 , and common elements have been given the same reference numerals. Rather than using a rod to actuate the upper and lower latches, the lock assembly 200 uses a non-rigid device, and specifically a cable 204 . The cable has an inner core 208 fixed to a vertically movable member 212 that is similar to the middle section 86 of the lock assembly 10 . The member 212 moves in response to movement of the lifter 100 in the same way the rod 74 moves. The cable 204 also has a sheath 216 that is fixed relative to the door. The opposite end of the cable 204 is connected to an upper latch (not shown). One skilled in the art can easily understand how the latch 38 can be actuated by the cable, or other types of latches can be employed. The upper latch can be connected to a lower latch by another cable, or another cable can be connected between the member 212 and a lower latch. Also, a push-pull cable can be connected between the top of the member 212 and the upper latch.
[0024] Various features and advantages of the invention are set forth in the following claims. | A mortise lock comprising: a case having opposite inner and outer sides which are horizontally spaced when the mortise lock is mounted on a door; a latchbolt supported by the case for movement between extended and retracted positions, the latchbolt extending from the outer side of the case; an element configured to be operably connected to a latch adjacent a top or a bottom of the door, the element being movably supported by the case and partially extending from the inner side of the case; and a latchbolt bar movably supported by the case, the latchbolt bar having an outer end operably connected to the latchbolt for moving the latchbolt between the extended and retracted positions, and the latchbolt bar having an inner end operably connected to the element for moving the element when the latchbolt bar moves the latchbolt. | 4 |
FIELD OF THE INVENTION
The present invention relates to digital signal transmission systems, and more specifically to digital signal transmission systems using adaptive predictive coding techniques.
BACKGROUND OF THE INVENTION
Adaptive predictive coding (APC) methods are widely used for high quality coding of speech signals. The details are discussed in U.S. patent application Ser. No. 07/603,104 by the present inventor and commonly assigned to COMSAT and which issued as U.S. Pat. No. 5,206,884 on Apr. 27, 1993. That application is herein incorporated by reference.
The concept of prediction filtering followed by residual quantization forms the basis for a wide range of coding techniques at various bit rates and quality for voice signals. The most direct implementation of this concept is found in adaptive predictive coding (APC) (B. S. Atal, "Predictive Coding of Speech at Low Bit Rates," IEEE Transactions on Communications, Vol. Com-30, No 4, April 1982). In APC, signal correlations are significantly reduced by adaptive short and long term prediction filters. The residual signal is then quantized by an adaptive quantizer, inside a quantization noise feedback loop. The adaptation ensures that the parameters of the predictors and the quantizer match the characteristics of the quasistationary input signal, so that the efficiency of these operations is maximized. In forward block adaptation, the signal is processed in blocks and parameters are determined for each block based on the uncoded signal. This form of adaptation requires the transmission of the prediction and quantization parameters along with the transmission of the residual. Backward sample adaptation is also possible, leading to analysis by synthesis schemes such as the low delay code excited linear prediction (LD-CELP). The proposed invention is relevant to the forward adaptive schemes.
The size of the block is highly dependent on signal characteristics and in particular on the quasistationary behavior of the signal. For telephony voice signals, sampling rates are generally in the range 6.4-8 kHz. At these sampling rates, block sizes are in the range 160-256 sample/block. For generality, block size will be denoted by N in the following discussion.
Prediction Filtering
Prediction is usually carried out in two states: a short delay predictor that removes adjacent sample correlations followed by a long delay predictor that removes correlations at longer delays. For voice signals, the short delay predictor removes the resonances due to the vocal cavity formants and the long delay predictor removes the periodicity introduced by the pitch periodic glottal excitation during voiced sounds. The short term prediction filter is defined by its transfer function S(z): ##EQU1## where M is the order of short term prediction, usually 8-16, and {a m , 1≦m≦M} are the linear prediction coding (LPC) coefficients. Similarly, the long term prediction filter transfer function L(z) is given by: ##EQU2## where p is the delay value (for voice signals usually equalling the pitch period, limited to 20<p<120 at 6.4-8 kHz sampling rates), and {c m ,p-1≦m≦p+1} are the long term prediction parameters. For each input signal block of N samples, these parameters (i.e., {a m }, {c m } and p) are determined by well known methods, (L. R. Rabiner and R. W. Schafer, "Digital Processing of Speech Signals," Prentice-Hall, Inc., Englewood Cliffs, N.J. (1978)), quantized for transmission and used for performing the prediction filtering operations. For telephony voice, about 64 bits are needed for adequate quantization of the parameters for each block of the input signal.
Residual Quantization
Let {x(i), 0≦i<N} denote the current block of N samples. The prediction residual r(i) is obtained by
r(i)=S(z)L(z)x(i), 0≦i<N.
The residual signal has to be quantized at a low bit rate, typically at 1-2 bit/sample. For example, for encoding voice sampled at 6.4 kHz at 16 kbit/s rate, 2 bits are available for the quantization of each sample of the residual signal. Quantization has to be carried out such that the quantization resultant impairment in the reconstructed version of the input signal is minimized (N. S. Jayant and P. Noll, "Digital Coding of Waveforms," Prentice-Hall, Inc., Englewood Cliffs, N.J. (1984)). For voice and audio signals, it is also important to minimize the impairment as perceived by the human ear. In order to realize this goal, the auditory masking properties of the human ear must be taken into account during residual quantization.
Existing Method: Noise Feedback Quantization
In APC, the residual is quantized inside a feedback loop which filters the quantization noise through a noise shaping filter 1 and sums the result using adder 2 with the residual to form the quantizer 3 input. The scheme is shown in FIG. 1. It should be noted that time domain samples are quantized directly. The power spectrum of the reconstruction noise is controlled by the transfer function of the feedback filter. The desired spectral shaping is achieved by using a feedback filter with the transfer function F(z) given by:
F(z)=(1-C(z))A(z/B)+C(z).
where β is limited by 0≦β≦1 and is usually 0.7.
Disadvantages of the Noise Feedback Quantization Scheme
There are two main disadvantages to the above scheme. First, due to the noise feedback, the variance of the quantizer input signal is higher than the variance of the residual. This is especially true due to the low rate quantization. As a result, the performance of the quantizer, referenced to the residual variance, will be reduced. Secondly, and more significantly, the feedback loop may become unstable if the power gain through the feedback filter becomes large. This can occur during signals of large spectral dynamic range such as sinusoids and resonant voiced sounds. Controlling the stability by limiting the power gain usually results in a loss in the overall performance of the codec.
SUMMARY OF THE INVENTION
It is an object of the present invention to obtain quantization of a residual signal without the disadvantages discussed above with respect to the prior art.
This invention pertains to a method and apparatus for quantizing a residual signal that is encountered in predictive coding techniques. These techniques are commonly applied to voice and audio signals to reduce the bit rate required for transmission while maintaining a certain level of quality. In particular, the proposed technique is applicable to transmission of signals at the rate of 1-2 bit/sample while maintaining subjective transparent quality.
In predictive coding, reduction in transmission bit rate is accomplished by the removal of signal redundancies by prediction filtering. The prediction filtering operation results in a residual signal whose information content is highly nonredundant and has to be quantized by a low rate quantizer and transmitted to the receiver. The residual quantization is crucial since it determines to a large extent the quality that is attainable by the technique at a given bit rate.
Existing approaches to residual quantization at the above transmission rates are usually implemented in the time domain. This invention proposes the Transform Domain Vector Quantization (TVQ), a novel approach to implementing the residual quantization. Here, the residual is first transformed from the time domain to a transform domain by an orthogonal transform such as the discrete cosine transform (DCT). The resulting transform coefficients are grouped into vectors. This grouping is performed in an adaptive manner, based on the spectral power distribution of the input signal. The bits available for the transmission of the residual signal are divided equally among the vectors. Each of these vectors is quantized by a vector quantizer. A weighting function that takes into account the auditory noise masking properties of the human ear as well as the synthesis filter response characteristics is used to select the optimum code vector to represent each transform coefficient vector.
At the receiver, the adaptive vector formation is reconstructed and the transform coefficients are decoded. These are then inverse transformed to yield a (quantized) residual signal. This signal is used at the input to the synthesis filters to regenerate the input signal.
The proposed invention addresses the residual quantization aspect of predictive coding. In TVQ, the residual signal is transformed into a transform domain. In the transform domain, quantization and spectral shaping are implemented as open loop operations. Consequently, the problem of instability does not arise. For the same reason, increase in the variance of the residual is also not encountered. In addition, the transform domain operation is a block quantization scheme that is easily amendable to variable bit rate operation. Variations in sampling rate and bandwidth are also easily implemented.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a prior art Noise Feedback Time Domain Quantization System;
FIG. 2 shows an encoder according to the present invention; and
FIG. 3 shows a decoder according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The proposed technique addresses the residual coding aspect of predictive coders. It is independent of the prediction analysis and filtering methods used in the coder, though prediction parameters are used for quantization and noise spectral shaping. Hence, in the following description, the prediction analysis and filtering will not be discussed further.
FIGS. 2 and 3 are block diagrams of the encoder and decoder that illustrate the TVQ method for the case of 8 kHz sampling rate, N=128 samples/block, and residual quantization with a total of 192 bits (equivalently 1.5 bit/transform coefficient). The prediction and quantization parameters are transmitted using 64 bits, resulting in a bit rate of 256 bits/block or 16 kbit/s. Clearly, by varying the sampling rate, the number of bits used for residual quantization (and parameter quantization to a more limited extent), other bit rate/bandwidth combinations can be obtained with corresponding variations in quality.
FIG. 2 shows the encoder of the present invention. Short term predictor circuit 21 and long term predictor circuit 22 are well known (and described in the above-referenced U.S. Pat. No. 5,206,884 and will thus not be described here further.
Transform Domain Vector Quantization circuit 23 includes DCT circuit 24, adaptive vector formation and normalization circuit 25, input signal power spectrum estimation circuit 26, codebook circuit 27 and quantizer 28. Multiplexer 29 is also shown.
In FIG. 3, for the decoder, analogous reference numerals (31-39) are used for analogous (to numerals 21-29 of FIG. 2) circuit elements.
The TVQ method can in general employ a broad class of orthogonal transforms. However, sinusoidal transforms such as the discrete cosine transform (DCT) and discrete fourier transform (DFT) have the advantage that the masking properties of the ear can be easily interpreted in the transform domain. For the sake of clarity and illustration, the DCT will be used in the following description. However, it should not be overlooked that a wide class of transforms can be substituted in place of the DCT without any major changes to the basic concept.
It is desirable to use a block size N that is an integer power of 2, to permit use of fast transform algorithms such as the fast fourier transform (FFT) and the fast cosine transform (FCT).
Domain Transformation
Let {r(i) ,0≦i<N} be the residual samples being encoded. Domain transformation results in a set of transform coefficients {R(k), 0≦k<N}. If DCT is used, transform coefficients are obtained by: ##EQU3## where,
δ(k)=1 k=0
δ(k)=√2 1 ≦k<N.
DCT circuit 24 receives the time domain residual signal and transforms it into the frequency domain according to the above equations.
Adaptive Vector Formation
The set of N transform coefficients are grouped into L vectors, each of dimension D, such that N=LD by circuit 25. The dimension D and the number L of the vectors are design parameters that are determined apriori based on considerations such as computational complexity and storage requirements of the coder. For residual quantization at 1.5 bit/transform coefficient, which corresponds to the rates of interest here, a vector dimension of D=8 leads to a 12 bit codebook, which is of reasonable complexity. In this case, the N transform coefficients are grouped into N/8 vectors of dimension 8.
The grouping of transform coefficients into vectors is not arbitrary, but must satisfy an important requirements that depends upon the power spectral density of the input signal, as modeled by the short and long term prediction parameters. Let V be a vector of transform coefficients given by ##EQU4## where,
i.sub.k ε(0,1,2, . . . ,N-1), 0≦k≦D.
Let H(k) denote the synthesis filter frequency response at the frequency 2πk/N. H(k) is expressed in terms of the short term predictor parameters {a i , 1≦i≦M} and long term predictor parameters p and {c i , p-1≦i≦p+1} as ##EQU5## Then each vector V=[R(i 1 )R(i 2 ) . . . R(i D )] T must satisfy the condition ##EQU6## In other words, the average log magnitude synthesis response for each vector must equal the average log magnitude synthesis response for all the transform coefficients. This condition ensures that all vectors have the same entropy, and hence can be quantized using the same number of bits. In general, the grouping is nonunique. Further, it is possible to generate extreme examples where such a grouping is not possible at all. However, for practical signals, a satisfactory grouping can always be obtained. Input signal power estimation circuit 26 supplies an estimate of the input signal power to the circuit 25 so that the above equations may be carried out by circuit 25. Circuit 26 produces an estimate of the input signal power from the long term and short term parameters in a well known fashion (as described in U.S. Pat. No. 5,206,884.
Adaptive Grouping Algorithm
The formation of the vectors that meet the above requirements is performed by an adaptive grouping algorithm. A grouping that exactly meets the above condition usually requires a large amount of computation. As a result, in practice, a vector formation that approximately satisfies the above condition is used.
There are a number of approaches to constructing the adaptive grouping algorithm. Here, an approach based on progressive binary grouping is proposed that is suitable when the dimension D is an integer power of 2.
The algorithm initially forms groups of two transform coefficients such that the average log magnitude synthesis response for each pair is as close as possible to the overall average. This is accomplished by selecting each (ungrouped) transform coefficient and grouping it with the transform coefficient among the remaining (ungrouped) transform coefficients that makes the average of the pair closest to the overall average. In this manner, the N transform coefficients are grouped into ##EQU7## transform coefficient subgroups.
In the next pass, the subgroups are paired to form larger subgroups by using the same criterion as above. Each subgroup is treated as a unit and the transform coefficients that compose the subgroup are not separated. This process is repeated until groups of the desired dimension are obtained. In other words, to obtain vectors of dimension D, the algorithm also generates subvectors of dimension ##EQU8##
The adaptive vector formation can be recovered exactly at the decoder in the absence of channel impairments. This is since the algorithm uses quantized short term and long term parameters that are also available at the decoder.
Vector Quantization
The total available number of bits for the quantization of the residual signal is divided equally among the vectors. For example, if 192 bits are available for quantization of 128 transform coefficients divided into 8 dimensional vectors, each vector is quantized using a 12 bit codebook stored in codebook circuit 27. The codebooks are populated by random variates of a suitable distribution. If DCT is used, the codebook is populated by univariate, zero means Gaussian random variables. The transform coefficients are normalized to unit variance and the normalization constant is log quantized using 7 bits and transmitted to the decoder.
Each vector is quantized by quantizer circuit 28 by an exhaustive search in the codebook. The optimum codevector is determined by a total weighted squared error criterion. The weighting is determined by the long and short term predictor parameters and a noise masking parameter β. The weighting coefficient for transform coefficient R(k) is w(k) which is given by ##EQU9## The noise masking parameter β is usually between 0.7 and 0.9. Corresponding to the normalized transform coefficient vector V defined earlier, the weighting vector W is defined as ##EQU10## Then the weighted error measure E n between the transform coefficient vector V and the n th codevector U n is computed by
E.sub.n =[W.sup.T (V-U.sub.n)(V-U.sub.n).sup.*T W],
where * represents complex conjugation and T represents transposition. For real transforms such as the DCT the above expression simplifies to
E.sub.n =[W.sup.T (V-U.sub.n)].sup.2.
Each transform coefficient vector is quantized to the codevector that results in the smallest error measure. The index of each codevector is sent to multiplexer 29 to be transmitted to the decoder, along with the bits encoding the short and long term parameters and the variance normalization factor.
A vector quantization technique is also disclosed in Ser. No. 07/732,024 involving the same inventor and assignee and is herein incorporated by reference.
Inverse Transformation and Decoding
At the decoder, as shown in FIG. 3, the predictor parameters are decoded and are used to determine the vector formation by circuit 35 by the same procedure as used at the encoder. Then the transform coefficient vectors are decoded by table look-up operations by circuit 38 in the codevector table in circuit 37. The transform coefficients are inverse transformed by circuit 34 to obtain the decoded version of the residual signal. Let {R'(k), 0≦k<N} denote the decoded transform coefficients. The inverse transform, in the case of the DCT is given by ##EQU11## where,
δ(k)=1 k=0
δ(k)=√2 1≦k<N
and {r'(i),0≦i<N} denotes the decoded version of the residual signal. This signal acts as the excitation to the cascade of long and short term synthesis filters (32 and 31, respectively) to generate the decoded version of the input signal. The transfer functions of the long and short term synthesis filters respectively are given by ##EQU12##
Features of the Invented Technique
In summary, the following are important features of the invention:
1. The prediction residual is quantized in a transform domain.
2. The choice of the transform is not as crucial as in other frequency domain coders such as transform coders. Transforms based on the discrete cosine transform and discrete fourier transform may be used with equally good results.
3. The prediction residual is quantized by vector quantization, where the vectors are formed adaptively, depending on the spectral power distribution of the input signal.
Although specific examples of the invention have been set forth above, the invention is not to be so limited. The proper and intended scope of the invention is defined by the claims. | Before transmitting signals to a receiver, the signals are subjected to adaptive prediction to generate a residual signal for transmission, and the residual signal is then transformed into frequency domain coefficients, the coefficients are grouped together to form vectors, and the vectors are then quantized. | 6 |
THE TECHNICAL FIELD OF THE INVENTION
[0001] The invention relates to the design of medication delivery systems with a view to compactness, reliability, weight and production cost.
[0002] The invention relates specifically to: A portable medication delivery device comprising a medication cartridge having an outlet and a movable piston, and a housing for holding said cartridge, and a flexible piston rod being operable to engage and displace said piston along an axis of said cartridge, and guiding means for bending said piston rod away from said axis, and actuating means, and driving means for transferring movement from said actuating means to said piston rod, said driving means including a driving wheel for displacing the piston rod, said flexible piston rod comprising regularly spaced first members adapted to mechanically cooperate with corresponding second members on said driving wheel.
DESCRIPTION OF RELATED ART
[0003] The following account of the prior art relates to one of the areas of application of the present invention, medication delivery systems for self-treatment of a disease.
[0004] In a medication delivery system for self-treatment of a disease such as diabetes, safety and convenience in the handling of the injection or infusion are of major importance. One very important aspect of this is compactness of the device. Another very important aspect for a user is to ensure that a correct intended dose is delivered. For the manufacturer of the devices aspects such as production control (testability) and economical solutions are important. A handy, i.e. small volume and lightweight, device that is highly reliable and at the same time economical in production is in demand.
[0005] U.S. Pat. No. 5,637,095 discloses a medication infusion pump with a flexible drive plunger comprising a spring tape. In one preferred form of the invention, the spring tape is wrapped or coiled onto a take-up spool within the pump housing. Drive means such as a drive capstan roller and associated pinch roller engage and advance the spring tape under control of the pump drive motor to correspondingly engage and advance the piston to deliver medication to the patient in a programmed manner.
[0006] EP-A-0 110 687 discloses a portable fluid infusion device including a flexible piston rod assembly. Attached to the piston is a flexible pusher tape, reversely bent in a U-shape at the upstream or open end of the syringe so that the distal end of the tape is adjacent to and in a position to ride upon the cylindrical body of the syringe as the piston is moved within the body of the syringe. The flexible pusher tape is made of a readily flexible plastics material such as a molded polypropylene. A series of parallel grooves are preformed in the face of the plastics tape along the narrow center portion thereof. The outwardly extending face of the tape is engaged by the helical drive screw at the part of the piston rod, which is deflected away from the axis of the cartridge. The rotation of the screw by a DC motor propels the tape in its U-shaped path to drive the piston.
DISCLOSURE OF THE INVENTION
[0007] The problems of the prior art are that the driving means are located relatively far from the piston and require a relatively thick piston rod having a relatively high friction with the housing and the cartridge, thus requiring a relatively high power consuming motor to advance it and possibly introducing inaccuracies in the displacement of the piston, or that the means for advancing the tape-shaped piston rod, the take-up spool storing the unused part of the tape, and the drum or wheel that supports the U-shaped path of the tape are individual self-contained functional units, yielding a relatively complex solution.
[0008] The object of the present invention is to provide a medication delivery system that combines compactness with an improved accuracy.
[0009] This is achieved according to the invention in that said flexible piston rod exhibits a linear or approximately linear path between said driving wheel and said piston.
[0010] In the present context, the term ‘medication delivery system’ is taken to mean an injector type device (such as a pen injector or a jet injector) for delivering a discrete dose of a liquid medication (possibly in the form of small drops) or a medication pump for continuous delivery of a liquid medication—in both cases optionally in combination with relevant electronic monitoring and control and possibly communications units.
[0011] In the present context the term ‘piston’ is taken to mean a displaceable plate or cylinder that fits tightly against the inner walls of a cartridge. A surface of the piston that faces the inner part of the cartridge and which may be brought into contact with the contents of the cartridge is termed ‘the inner surface of the piston’, and the opposite side of the piston is termed ‘the outer surface of the piston’. In cooperation with a ‘piston rod’ that is engaged with ‘the outer surface of the piston’, the ‘piston’ may be displaced and used to apply pressure to a surface of the contents of the cartridge being in contact with ‘the inner surface of the piston’, thus e.g. delivering a dose through the outlet of the cartridge, if the piston is displaced in the direction towards the outlet. In the present context, the term ‘piston’ may also apply to a movable wall or membrane that engages with a plunger being an integral part of the piston rod.
[0012] In the present context, the term ‘piston rod being operable to engage and displace said piston’is taken to mean that the piston rod may or may not be fixed to the movable wall, but that in both cases it has the ability to displace the piston at least in a direction towards the outlet of the cartridge.
[0013] In the present context, the term ‘driving wheel’ is taken to mean the part of the driving means that cooperates with the activating means (e.g. an electromotor) and the piston rod to transfer the movement of the activating means to a displacement of the piston rod. It may take the form of a gear wheel or drum or any other appropriate form that may be adapted to cooperate with the piston rod. A gear box may be inserted between the activating means and the driving wheel.
[0014] An advantage of having a linear path of the piston rod between the driving wheel and the piston is that the risk of introducing errors in the displacement of the piston by the rod is reduced because a more direct drive of the piston is provided (i.e. the sources of mechanical inaccuracies from a remotely located driving wheel due to the curved path, extra friction of the guiding means, etc. are eliminated). Related advantages of this are that an improved dose accuracy may be achieved and that the requirements with respect to the power of the activating means are reduced, leading to a possible reduction in weight and volume of the device.
[0015] A further improved dose accuracy may be achieved by combining the present invention with the invention disclosed in our co-pending patent application A medication delivery system with improved dose accuracy incorporated herein by reference.
[0016] Other advantages of the invention are that it uses a simple principle for transferring rotational movement of the actuating means to translatory movement of the piston rod, a principle that may be implemented in many different ways depending on the design constraints as regards space and materials. It allows the construction of a relatively compact medication device (utilizing e.g. a 180 degrees curve of the path of the piston rod), using a relatively thin piston rod yielding the benefits of a low weight and a potentially economical solution that is suited for large-scale production.
[0017] When said flexible piston rod remains in a fully reversible elastic state during cooperation with said driving wheel and said guiding means, it is ensured that the piston rod is able to adjust to the various curvatures of the driving and guiding means and cooperate therewith, without being irreversibly deformed.
[0018] When the surface of said flexible piston rod in a transversal cross-section is adapted to follow the surface of said driving wheel fully or partially, it is ensured that the change of the cross-section of the piston rod during its bending cooperation with the driving and guiding means is accounted for to ensure a seamless cooperation between the rod and the driving and guiding means.
[0019] When said guiding means also work as a take-up spool for storing the unused part of the piston rod, it is ensured that an especially compact and economical solution is provided.
[0020] When said driving wheel and said guiding means are the same physical unit, it is ensured that an especially simple, compact and economical solution is provided.
[0021] When said driving wheel is located after said guiding means in a downstream direction towards said cartridge, it is ensured that the driving means are located as close as possible to the piston to be displaced, thus minimizing the sources of errors and improving dose accuracy.
[0022] In the present context, the term ‘downstream’ is taken to mean in a direction of the movement of the piston when medication is expelled from the cartridge, said direction also defining a ‘longitudinal direction’ of the piston rod.
[0023] When said piston rod touches the inner walls in an axial direction of said cartridge at one or more points in a transversal cross-section of said piston rod, it is ensured that the ability of the rod to withstand an axial pressure is improved.
[0024] In the present context ‘the inner walls of the cartridge’ are taken to mean the interior surfaces of the walls of the cartridge being in contact with the medication. ‘A transversal cross-section of the piston rod’ is taken to mean a cross-section of the rod that is perpendicular to the longitudinal direction of the piston rod, i.e. for the part of the rod between the driving wheel and the piston, a direction perpendicular to the direction defined thereby (i.e. perpendicular to the axial direction of the cartridge).
[0025] When the longitudinal edges of said piston rod in the cartridge touch the inner walls of said cartridge, it is ensured that the piston rod is guided when displacing the piston in the cartridge, improving the ability to withstand an axial pressure.
[0026] In the present context the term ‘the longitudinal edges of said piston rod in the cartridge’ refers to the edges of the rod in a direction defined by the longitudinal direction of the piston rod.
[0027] When said flexible piston rod is tape-shaped, it is ensured that a solution that is convenient from a production point of view and which is well suited for coiling is provided, and that an improved flexibility in the physical design of the medication delivery system is introduced.
[0028] In the present context the term ‘tape-shaped’in connection with ‘piston rod’ is taken to mean that the cross-section of the rod perpendicular to its longitudinal direction is ‘wider’ than its ‘height’. It does not have to take the form of a rectangular cross-section but could be grooved or toothed or wave-shaped or convex or concave or something else that might be convenient from a design point of view.
[0029] When said flexible piston rod consists of two separate tape-shaped bodies that are joined together at one or more points in a transversal cross-section, it is ensured that a greater axial pressure may be applied to the rod compared to a ‘single layer’ solution, in other words that thinner materials may be used, resulting in lower weight and reduced costs and thus a greater degree of freedom in the design of the medication delivery device. Further, the piston rod may be subject to a sharper bend than a corresponding one-layer rod. A tape-shaped piston rod that is sufficiently stiff in itself (i.e. without touching the inner walls of the cartridge) may thus be provided.
[0030] In a preferred embodiment said two separate tape-shaped bodies are joined together in the central point of a transversal cross-section.
[0031] In a preferred embodiment the distance between said two tape-shaped bodies increases with increasing distance from said central point when viewed in a transversal cross-section in a relaxed state.
[0032] In the present context the term ‘in a relaxed state’ refers to a situation in which no external forces (other than gravity) are applied to the rod.
[0033] When said two separate tape-shaped bodies are joined together at the edges of a transversal cross-section, it is ensured that an economical and light-weight solution that is well suited for production in larger quantities is provided, and which may be bent around a relatively smaller minimum radius of curvature.
[0034] In a preferred embodiment, said edges are joined by applying a coating layer to the surface of said separate tape-shaped bodies. This has the advantage (in addition to joining the two bodies by forming a continuous and flexible hinge between their corresponding longitudinal edges) of yielding a very even surface of the rod and provides the possibility of applying a coating that is especially appropriate for the application in question, e.g. that it minimizes friction, that it improves corrosion resistance, etc.
[0035] In a preferred embodiment said two tape-shaped bodies describe an eye-shaped path when viewed in a transversal cross-section in a relaxed state.
[0036] In a preferred embodiment said first members on said flexible piston rod comprise protruding members and said corresponding second members on said driving wheel comprise receiving members. In an embodiment thereof, the driving wheel comprises e.g. regularly spaced indentations that interact with corresponding protrusions on the piston rod to displace the piston rod. This has the advantage that the protrusions are ‘hidden’ in the driving wheel when the piston rod engages the wheel, possibly reducing the free space needed around the driving wheel (thus minimizing the volume of the construction).
[0037] In a preferred embodiment said first members comprise receiving members and said corresponding second members comprise protruding members.
[0038] In a preferred embodiment said first members comprise individually isolated indentations and said corresponding second members comprise individually isolated projecting members.
[0039] When said first members comprise individually isolated through holes and said corresponding second members comprise individually isolated projecting members, it is ensured that a secure grip between piston rod and driving wheel is provided.
[0040] In a preferred embodiment said regularly spaced members are located along a centerline in the longitudinal direction of said flexible piston rod.
[0041] When said first members comprise individually isolated cuts located at least along one periphery in the longitudinal direction of said flexible piston rod and said corresponding second members comprise individually isolated projecting members, it is ensured that a secure grip between piston rod and driving wheel is provided. Further, a greater axial stiffness of the rod is achieved.
[0042] When the piston rod is at least partially made of a plastics material, it is ensured that a solution combining the benefits of using a plastics material (e.g. corrosion resistance) with those of other materials (e.g. greater mechanical stability, stiffness, etc.) may be provided.
[0043] In a preferred embodiment the piston rod is at least partially made of a metallic material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The invention will be explained more fully below in connection with a preferred embodiment and with reference to the drawings, in which:
[0045] [0045]FIG. 1 shows a medication delivery system according to the invention where the driving wheel is located next to the medication cartridge,
[0046] [0046]FIGS. 2. a - 2 . b show an embodiment of the invention where driving wheel and guiding means are one physical unit,
[0047] [0047]FIGS. 3. a - 3 . d show various embodiments of a tape-shaped piston rod according to the invention,
[0048] [0048]FIGS. 4. a - 4 . c show a tape-shaped piston rod and corresponding driving wheel according to the invention for which a coiling of the tape on the driving wheel is possible,
[0049] [0049]FIG. 5 shows a medication delivery system according to the invention where the driving wheel in the form of a screw is located between the guiding means and the medication cartridge,
[0050] [0050]FIGS. 6. a - 6 . b show some possible designs of a piston rod according to the invention, and
[0051] [0051]FIGS. 7. a - 7 . b show some possible designs of a piston rod and a driving drum according to the invention.
[0052] The figures are schematic and simplified for clarity, and they just show details which are essential to the understanding of the invention, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts.
DETAILED DESCRIPTION OF EMBODIMENTS
[0053] [0053]FIG. 1 shows a medication delivery system according to the invention where the driving wheel is located next to the medication cartridge.
[0054] In the embodiment of the medication delivery system 1 in FIG. 1, a medication cartridge 11 (possibly a replaceable one) with a piston 112 and an outlet 111 to which a needle 22 (possibly replaceable) may be fixed, is shown to cooperate with a piston rod 13 in the form of a tape, the tape being arcuate (cf. correspondingly FIG. 2. b ) in a transversal cross-section. The cartridge 11 is removably fixed to a cartridge holder 12 . The piston rod 13 may be displaced along a longitudinal axis 113 of the cartridge 11 . A downstream direction is defined by the arrow 1131 . The movement of the piston rod 13 is activated by an electromotor 15 whose rotational movement is transferred to a linear displacement of the piston rod by suitable driving means, the driving means comprising inter alia a driving wheel 17 with regularly spaced protruding members 171 that are adapted to cooperate with corresponding regularly spaced openings (cf. 331 in FIGS. 3. c and 3 . d ) on the piston rod. The piston rod 13 is bent to make a 180 degrees U-turn over a first guiding wheel 14 . A second guiding wheel 18 ensures a proper contact between the piston rod and the driving wheel 17 . In the embodiment of FIG. 1, the faces of the second guiding wheel 18 and the driving wheel 17 that receive the tape-shaped piston rod 13 have a concave face and a corresponding convex face, respectively. This has the effect that the piston rod acquires its normal arcuate form in a transversal direction of the rod appropriately adjusted to the diameter of the medication cartridge (e.g. so that the edges of the piston rod (and not the central part of the rod) touch the inner walls of the cartridge (cf. FIG. 2. b ). The receiving faces of the guiding wheels 14 , 18 and driving wheel 17 may of course take other forms that are convenient from a design point of view.
[0055] In an embodiment of the invention, the piston rod 13 is adapted to elastically adjust fully or partially to the shape of the surfaces of the driving wheel 17 and the guiding wheel 14 along its path of contact with said wheels. Alternatively, the surfaces of the wheels are adapted to match fully or partially the shape of the side of the piston rod that engages with the wheels when the piston rod is bent around the wheel in question. This applies to the longitudinal as well as the transversal directions of the rod. In the longitudinal direction, the smallest diameter of the wheel is limited by the smallest diameter around which the rod may be elastically bent (i.e. reversibly). In the transversal direction, for the embodiment in FIG. 6. a , for example, this means that the eye-shaped cross-sectional view ‘collapse’ to a shape that follows the wheel in question.
[0056] In another embodiment of the invention, the width of the driving wheel (and possible guiding wheels) is smaller than the width of the tape-shaped rod when viewed in a transversal cross-section (cf. FIG. 7. a ). In this case, a piston rod with centrally located (cf. e.g. FIG. 3. a , 3 . c or 6 . a ) or nearly centrally located (cf. FIG. 3. d or 6 . b ) is used.
[0057] In an embodiment of the invention said first guiding wheel 14 is substituted by a fixed guideway (providing an equivalent bending of the piston rod), optionally coated with a layer that ensures a low friction between guideway and piston rod. The transversal cross-section of the guideway is adapted to match fully or partially the shape of the side of the piston rod that engages with the guideway when the piston rod is bent around it during its normal operation.
[0058] When the medication cartridge is replaceable, it is ensured that the major part of the medication device may be used again and again only by inserting a new cartridge (and possibly a new needle in the case of an injection device) when the contents of the medication cartridge has been ejected or when another medication is to be used, i.e. e.g. in the situation of a person's self-treatment of a disease (e.g. diabetes) that requires frequent delivery of medication (e.g. insulin) over an extended period of time. If the replaceable cartridge contains a fully functioning piston (and possibly a corresponding piston rod), a convenient and flexible solution is provided, where the medication cartridge may be replaced in a quick and hygienically safe way.
[0059] To ensure that the piston rod follows the guiding wheel 14 along the relevant part thereof, the ‘upstream’ end of the piston rod (i.e. the end of the rod that does not engage the piston) may be connected to a part of the medication device that is held fixed relative to the cartridge by a salient element (e.g. a spring, not shown) whose one end is tied to the piston rod and whose other end is held fixed.
[0060] Typically, the medication delivery process including analysis and use of historical data concerning the device and user in question, diagnostic proposals, error correction, etc. is governed by appropriate processing and communications units.
[0061] In the embodiment in FIG. 1. a the driving means include appropriate means 16 for transferring movement from the electromotor 15 to the driving wheel 17 , e.g. in the form of a gear box. The electromotor is controlled by a processing unit 19 (including relevant memory means). The processing unit 19 may exchange information with the user and other systems via I/O-means 20 (comprising e.g. a display, keypad, and relevant communications interfaces). The electronic units are powered from the energy source 21 (e.g. a battery pack or an interface to external energizing means).
[0062] A housing 10 for protecting and optionally supporting the piston rod at its 180 degrees path and for covering the electromotor and other vital parts of the device is provided.
[0063] The housing 10 , the cartridge holder 12 , the means 16 for transferring movement from the electromotor to the driving wheel, the electromotor 15 , the processing unit 19 , the I/O-means 20 and the energy source 21 are not included in FIGS. 2 and 5, but are implied.
[0064] [0064]FIGS. 2. a - 2 . b show an embodiment of the invention where driving wheel and guiding means are one physical unit.
[0065] In FIG. 2. a only the central features of the invention are illustrated. FIG. 2. a shows a driving wheel 17 with regularly spaced teeth 171 that cooperate with corresponding indentations on the piston rod 13 . When the driving wheel 17 is activated in a counterclockwise direction by the actuating means (not shown), the piston rod 13 is displaced in a downstream direction and acts to displace the piston 112 to expel medication from the cartridge 11 through the outlet 111 and an attached needle (not shown). By allowing the driving wheel to create the 180 degrees bending of the piston rod, a particularly simple embodiment is provided. Additionally, this embodiment is more compact and lighter.
[0066] [0066]FIG. 2. b shows a cross-sectional view of the medication cartridge 11 and the piston rod 13 along the line BB. The curved cross-section of the piston rod 13 is apparent. The edges 131 , 132 of the tape-shaped piston rod glide on the inner walls of the cartridge 11 , yielding a mechanically more stable construction in that a greater force may be applied to the tape rod, without it bending out of the linear path from the edge of the driving wheel to the point of engagement of the piston rod with the piston.
[0067] [0067]FIGS. 3. a - 3 . d show various embodiments of a tape-shaped piston rod according to the invention.
[0068] [0068]FIG. 3. a shows an embodiment of a tape-shaped piston rod 33 with parallel grooves 330 in a transversal (or nearly transversal) direction of the tape-shaped piston rod in a central part on the side of the tape that cooperates with a corresponding driving screw (cf. 17 in FIG. 5). The grooves may optionally extend through the material to form slots for cooperation with corresponding threads on the driving wheel.
[0069] [0069]FIG. 3. b shows an embodiment of a tape-shaped piston rod 33 with regularly spaced cut-outs 332 in each of the longitudinal edges of the tape for cooperation with corresponding projecting pins on the driving wheel (not illustrated). Put differently, the tape-shaped piston rod is provided with regularly spaced projecting members along its longitudinal edges and the driving wheel has corresponding receiving members to provide a secure grip of the piston rod when the rod engages with the driving wheel. This embodiment yields a very good grip between tape and wheel and a very accurate positioning in a transversal direction of the tape, both contributing to a more accurate dosage. It further provides a piston rod that is able to withstand a larger axial pressure (without bending) than corresponding solutions depicted in FIGS. 3. c and 3 . d.
[0070] [0070]FIG. 3. c shows an embodiment of a tape-shaped piston rod 33 with regularly spaced, centrally located rectangular through holes 331 in the tape for cooperation with corresponding projecting pins on the driving wheel (e.g. 171 in FIGS. 1 and 2).
[0071] [0071]FIG. 3. d shows an embodiment of a tape-shaped piston rod 33 with two rows of regularly spaced, circular through holes 331 located symmetrically around the longitudinal centre line of symmetry of the tape for cooperation with corresponding projecting pins on the driving wheel (not shown).
[0072] [0072]FIGS. 4. a - 4 . c show a tape-shaped piston rod and corresponding driving wheel according to the invention for which a coiling of the tape on the driving wheel is possible.
[0073] The piston 33 comprises a tape with centrally situated, regularly spaced circular holes 331 adapted to cooperate with corresponding protruding circular cylindrical members 361 on the driving drum 36 . The driving drum is activated by an electromotor (not shown) through appropriate driving means (e.g. a gear box, not shown). The holes are shown to be positioned along a centerline of the tape, but may of course be located at one or both longitudinal edges of the tape (cf. FIG. 3. b ) or along a line off the centre line or in any other convenient way as long as the protruding means on the driving drum follow a corresponding pattern. Likewise, the individual holes and corresponding protruding members may take on any convenient form, e.g. edged as opposed to circular, as long as the holes in the tape and the protruding members on the driving drum correspond.
[0074] [0074]FIGS. 4. a and 4 . b show orthogonal plane views of the piston rod and driving drum, whereas FIG. 4. c shows a perspective view of a coiled piston rod and illustrate the fact that the unused part of the tape/piston rod may be stored on the driving drum, yielding a simple and compact solution.
[0075] [0075]FIG. 5 shows a medication delivery system according to the invention where the driving wheel in the form of a screw is located between the guiding means and the medication cartridge.
[0076] [0076]FIG. 5 shows a driving screw 17 that cooperates with corresponding grooves (cf. 330 in FIG. 3. a ) on the piston rod 13 . When the driving wheel 17 is activated by the actuating means (not shown), the piston rod 13 is displaced in a downstream direction and acts to displace the piston 112 to expel medication from the cartridge 11 through the outlet and an attached needle (not shown). The piston rod makes a 180 degrees bend over a guiding wheel 14 . A second guiding wheel 18 ensures a proper contact between the piston rod and the driving screw 17 .
[0077] [0077]FIG. 6 shows some possible designs of a piston rod according to the invention.
[0078] The piston rod may be made in many different forms according to design requirements (materials, stiffness, weight, corrosion, etc.) and cost. The rod may be made of one longitudinal piece of material or alternatively be composed of several layers joined together at one or more points in a transversal cross-section of the tape. In the longitudinal direction, the tape may be joined together in isolated (possibly regularly spaced) ‘points’ or continuously. The joining may be performed by welding or adhesive techniques or any other appropriate joining technique.
[0079] [0079]FIG. 6. a shows a preferred embodiment of a tape-shaped piston rod 33 , where the rod is made of two identical longitudinal pieces 335 , 336 of foil that are joined together along their edges 131 , 132 and have centrally located 334 , regularly spaced openings 331 for cooperation with a driving wheel. The two individual pieces of tape have an arcuate cross-section in a relaxed state, thus forming an eye-shaped cross-section when joined at the edges. In a preferred embodiment the individual pieces of tape are made of a salient metallic material of 0.5 mm thickness and the joining is achieved by coating the outer surface with a ductile polymer layer. If appropriate, the layer may be applied to the inner surfaces of the rod or only along the joining lines of the rod. Alternatively, a ductile adhesive tape may be applied along the joining lines of the rod.
[0080] In another preferred embodiment, as depicted in FIG. 6 b , the rod 33 is made of two identical longitudinal pieces 337 , 338 of foil that are joined together along their centre lines 334 to give an X-shaped cross-section and having two rows of regularly spaced holes 3311 , 3312 for cooperation with a driving wheel. The holes are located on each side of the central point of the tape when viewed in a transversal cross-section of the rod. The holes are shown to be circular and quadratic, respectively, but they may take any form that is appropriate for cooperation with a driving wheel. Likewise indentations may be used depending on material thickness as long as a sufficient grip with the driving wheel is ensured.
[0081] [0081]FIGS. 7. a - 7 . b show some possible designs of a piston rod and a driving drum according to the invention.
[0082] [0082]FIG. 7. a shows an embodiment of the invention where the driving drum 17 with regularly spaced projecting pins 171 has a width 173 in the direction of its axis of symmetry that is much smaller than the width 335 of the tape-shaped piston rod 33 . The piston rod 33 has regularly spaced openings 331 located along a centre line 334 adapted to cooperate with the projecting pins 171 of the driving drum 17 . The piston rod has longitudinal edges 131 , 132 . The piston rod has an arcuate transversal cross-section in a relaxed state. The surface 172 of the driving drum facing the corresponding surface 133 of the piston rod (shown in FIG. 7. a in its relaxed state) is flat (linear as opposed to arcuate), but may take any convenient form as long as its width 172 is sufficiently small compared to the width 335 of the rod and the projecting pins provide a sufficient grip with the openings of the piston rod.
[0083] [0083]FIG. 7. b shows an embodiment of the invention where the driving drum 17 with regularly spaced projecting pins 171 has a width 173 in the direction of its axis of symmetry that is comparable to the width 335 of the tape-shaped piston rod 33 . Again, the piston rod 33 has regularly spaced openings 331 located along a centre line 334 , the rod having longitudinal edges 131 , 132 . The openings 331 are adapted to cooperate with the projecting pins 171 of the driving drum 17 . The piston rod has an arcuate transversal cross-section in a relaxed state. The surface 172 of the driving drum facing the corresponding surface 133 of the piston rod is arcuate and adapted to match the curvature of the piston rod fully or partially in a transversal cross-section, when the rod is brought into contact with and forced to follow a radial path of the drum (i.e. when the projecting pins of the drum cooperate with the openings of the piston rod). The arcuate surface 133 of the piston rod in a relaxed state is shown in FIG. 7. b . In general, the radius of curvature of the surface 172 of the driving drum contacting the piston rod is greater than the radius of curvature of the corresponding surface 133 of the transversal cross-section of the piston rod in a relaxed state, as indicated in FIG. 7. b . In a special embodiment the radius of curvature of the surface 172 of the driving drum contacting the piston rod is infinite (i.e. the surface is linear).
[0084] The piston rod and driving and guiding members should be designed in such a way that the piston rod, when cooperating with the said members, remains in a fully reversible, elastic mode of deformation (in its longitudinal as well as its transversal cross-sections). This may be achieved by a proper choice of materials and geometrical dimensions.
[0085] Some preferred embodiments have been shown in the foregoing, but it should be stressed that the invention is not limited to these, but may be embodied in other ways within the subject-matter defined in the following claims. | The invention relates to: A portable medication delivery device ( 1 ) comprising a medication cartridge ( 11 ) having an outlet ( 111 ) and a movable piston ( 112 ), and a housing ( 12 ) for holding said cartridge, and a flexible piston rod ( 13 ) being operable to engage and displace said piston along an axis ( 113 ) of said cartridge, and guiding means ( 14 ) for bending said piston rod away from said axis, and actuating means ( 15 ), and driving means ( 16, 17 ) for transferring movement from said actuating means to said piston rod, said driving means including a driving wheel ( 17 ) for displacing the piston rod ( 13 ), said flexible piston rod comprising regularly spaced first members ( 330; 331; 332 ) adapted to mechanically cooperate with corresponding second members ( 171 ) on said driving wheel. The object of the present invention is to provide a medication delivery system that combines compactness with an improved accuracy. The problem is solved in that said flexible piston rod ( 13 ) exhibits a linear or approximately linear path between said driving wheel ( 17 ) and said piston ( 112 ). This has the advantage of yielding a compact, low-weight device with an improved dose accuracy. The invention may e.g. be used in injection or infusion devices for a person's self-treatment of a disease such as diabetes. | 0 |
BACKGROUND OF THE INVENTION
The invention relates to a mast footing arrangement devised in particular for wind surfboards and being configured in a spherical mode.
As a matter of rule, mast footing arrangements for wind surfboards consist of a joint. This joint has to enable the mast to be swingable to all sides over the water level and to be rotatable about its longitudinal axis. In addition, the mast ought to be swayable not only down to its horizontal plane position, but by several degrees more beyond it, so that the swinging angle must exceed 180°. This is needed due to the fact that the mast footing joint is arranged on the boat body above the water surface and the mast has to be tiltable usually down to the water level.
The hitherto known mast footing joints include a universal joint, which joint is configured so that the mast may be swung to all sides and is disposed rotarily. The universal or cross joints however are complexly built-up and require a considerable material expenditure. Moreover, they are work consumptive in manufacture and expensive in mounting. Besides, they involve high risk of injury, especially for the feet of the user of the surfboard.
Precisely for the latter indicated reason, there already have been proposed other solutions which have been reduced to practice. Thus, there has become known a joint providing a connection of the mast end to the vessel body and ensuring mobility to all sides. Here each of the components of the joint includes a plugging connector for the attachment of the mast and the components or the vessel body. The mast and the components or vessel body are interconnected by means of a central rubber band located in their interior. However, this joint is also constructionally complicated, in particular, since there is to be taken a precautional measure ensuring that the respective component for the body be strongly tied to the boat body and be reliably kept thereby.
Furthermore, there is known a spherical joint mast footing arrangement preventing further inclination of the mast in the vertical plane of the sail board after a certain inclination has been reached. For achieving this, a bolt on the joint is connected to the mast and is guided over a slanting arched path of a double-part shell that is unturnably affixed to the boat body. This notorious joint arrangement considerably reduces the mobility of the mast and encumbers the joint with a lever-like load in the area of the connection thereof, so that the mast footing of the board experiences a strong wear. Now, in addition to all of this, there is obtained a swaying capacity angle not exceeding 180°. Also, the mast could unintentedly surge at the highest section of the path curvature from the board thus ensuing a considerable peril of injury.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a mast footing arrangement which avoids the disadvantages of the prior art.
More particularly, it is an object of the invention to provide a mast footing arrangement, which is unaffected by lever-like loading and which permits a swinging motion beyond 180°, as well as mast rotation over a full 360°, and in which any danger of injury is almost completely excluded. This arrangement is additionally easy to manufacture and mount, and also is produced with an advantage as concerns the costs.
In the mast footing arrangement of the kind alluded to in the introduction hereto, this problem is solved within the purview of this invention such that this novel mast footing arrangement is characterized in that it is formed by a pair of parts that are mutually assemblable by plugging. At least one part of this mast footing arrangement is lodged in the mast itself or in the boat body such that it is freely rotatable within the range of 360°. It is advantageous to have the portion of the joint associated to the boat body arranged to be rotatable in this boat body. In a specific embodiment of the invention, one part of the mast footing arrangement is configured as a ball-like body, preferably provided with a cylindrical bolt, while the other part consists in a cylindrical bolt carrying at its one end a spherically formed cup which latter includes at least three finger elements. In this case, it is particularly advantageous when this cup part is rotarily lodged in the boat body.
It has been established that this novel mast footing arrangement copes in an optimum manner with the requirements put in its regard. The same represents a security joint in which the transgressing of a certain pulling force causes that both the joint parts separate one from the other without any damaging effect in the way of their elastic snapping off. The same can thereafter be easily snapped together again. The limit pulling force and/or separating force depends on the elasticity of the cup fingers and can be correspondingly selected in advance by choosing an appropriate material therefor.
Another object of this invention is to construct the mast footing arrangement in a manner such that the separating force on the joint might be set up.
In the mast footing arrangement of the nature described, this object is solved in such a way that at least one finger element is arranged to be radially resettable. This is purposefully attained by providing an axially extending slot in the shell-like portion and/or in the root area of the cup, namely at least one such slot. Furthermore, at the outer side of the cup root, a conical annular surface is provided to run towards the cup, and this surface is threaded at the other side. Upon this treading, a nut is screwable which is configured in its region converted to the cup with an outwardly diverging annular surface, whose conical angle is preferably a little smaller than the conical angle of the conical annular surface on the cup root. It is particularly advantageous when a slit is provided at the side of each one of the fingers.
Though these provisions leave unchanged the radius of the spherical body and are surprisingly simple, they insure that the joint separation force is adjustable. It is self-speaking that it also is possible to slit the spherical body and to provide on the cylindrical bolt settable clamping means which in a special embodiment of the invention might be arranged on the cylindrical bolt of the cup member.
In effect of all of this, the here described invention makes possible in particular to achieve a strong attachment of the cylindrical bolt on the spherical portion to the boat body. According to a specific form of the execution of this invention, there is envisaged to provide the cylindrical bolt with a pair of mutually spaced elastic rings, either of which is embedded in a groove circumscribing the cylindrical bolt. In regard to the diameter of the bolt, the diameter of these rings is chosen to provide a coaction resulting in that, on insertion of the bolt into the therefor arranged opening in the boat body, a nearly air tight engagement is obtained. Although the joint and the mast sitting upon this joint can be slowly pulled out and detached, in case of an impulsive pulling force impact, a suction detaining force counteracts to prevent the mast footing from being suddenly torn out. It is thus essential that both of the sealing rings, which are made of an elastic material, maintain the cylindrical bolt in its opening duly centered and that they nearly totally eliminate any such displacement thereof.
In accordance with a specific embodiment of the invention, the shell portion and/or the root of the cup comprises at least one axially extending slot, that there is a conical annular surface outside the cup root diverging towards the cup and surrounded at its outer end with an adjacent threading and that there is a nut screwable onto this threading, which nut has further on the side facing the cup in its interior also a conical annular surface configured to diverge outwardly. The conical angle of this inner annular surface is preferably slightly smaller than the conical angle of the annular surface on the cup root.
It has appeared that this nut or similar screw means above or under the joint makes possible to fix a joint portion with a separable snap connector in the mast insertion piece.
Accordingly, the subject matter of this invention resides additionally in a mast footing arrangement equipped with a fixation means for one joint portion tied in the mast insertion piece.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1--the mast footing arrangement in sideview with cross-sectioned boat body;
FIG. 2--a first variant of this arrangement;
FIG. 3--a second variant of this arrangement;
FIG. 4--a third variant of this arrangement;
FIG. 5--a cross-sectional view of the cup portion;
FIG. 6--the spherical portion of the mast footing arrangement;
FIG. 7--the snapping closing means of one of the joint portions; and
FIG. 8--a fourth variant of the arrangement.
DESCRIPTION OF PREFERRED EMBODIMENTS
The mast footing arrangement encompasses a pair of joint portions 1 and 2. The spherical portion 1 and the cup portion 2 are made preferably of a plastic material, in particular of polyethylene or polyamide. The spherical portion 1 comprises a cylindrical bolt 5 and a ball-like body 3, which latter may be configured as a hollow sphere or also as a ball body flattened on one pole thereof. In this second case, it is requirable that the diameter of the flattened surface be smaller than the radius. The bolt 5 has a length and a diameter almost that of the receptive opening 9 in the boat body 7, whereinto this bolt is to be inserted. This bolt carries in a spaced relationship a pair of elastic rings 17, either of which is embedded in a corresponding groove 18, while both the rings exceed the diameter of the bolt. Thereby, the bolt 5 of the spherical portion 1 can rotate relative to the boat body. The cup portion 2 is configurated as a hollow ball and has associated thereto a cylindrical bolt (10), at one end whereof a spherically configured cup 11 is located. This cup 11 consists of a shell part 12 and of finger elements 13. The finger elements 13 also may start from the root 16 of the cup. The form of the finger elements may be freely selected, but, preferably, these finger elements, observed from the side, converge conically toward the apex and are formed with rounded free terminals. Their length is devised so that they transgress the equator of the spherical cup. The top opening diameter therebetween is smaller than the outer diameter of the sphere, but is larger than the diameter of the cylindrical bolt 5 of the spherical portion 1. It is preferable to have arranged three fingers of this kind, disposed in star-like mode at angles of about 120°. Quite naturally, there also could be provided more peripherally disposed fingers. Necessarily, the intermediate space 15 between the adjacent finger elements 13 must be dimensioned so that the bolt 5 of the spherical portion 1 can have a free access in this intermediate space 15 down to the shell portion border 14. In consideration of this requirement, the intermediate space 15 ought to correspond at least to the diameter of the cylindrical bolt 5 of the spherical portion 1. The height of the shell portion depends on the desired angle of the swaying capacity. However, the same is lower than that of a semi-spherical shell. The border 14 is limitative of the angle of the possible swaying declination of the mast.
It also is important that the diameter of the bolt 5 be chosen so that this bolt, on being tilted, comes first in contact with the border 14, when it has reached the desired inclination angle. For this reason, the bolt diameter and the shell height are to be correspondingly correlated. In a construction where no shell part is provided and the fingers, especially when they are three, depart from the cup root, there can be selected a particularly large diameter for the bolt.
According to one exemplary embodiment of the invention, the space between the finger elements 13 radially decreases in a manner such that there is provided sidewardly of each finger element a slot 19 axially running toward the bolt 10, so that the finger elements are enabled to be elastically moved to one another by action of a suitable resetting means. In one preferable embodiment, this resetting means consists in a conic annular surface 20 interconnecting the root 16 to the bolt 10 and in a treading 21 joining the mentioned conical annular surface. Upon this treading 21, a nut 22 with a threading 23 may be screwed which nut is provided in its region facing the cup with a conical annular surface 24. The conicity angle of this annular surface 24 is slightly smaller than the conicity angle of the annular surface 20. Accordingly, when the nut is screwed on the threading, the conical annular surface 24 abuts the conical annular surface 20 and, when its screwing is continued, the same provokes a closing motion of the cup as an effect of the narrowing of the slots 19. Notwithstanding the surprisingly simplicity of this provision, the same ensures that there is achieved a narrowing of the cup opening with the result that also the separating force becomes increased, namely the force needed for extracting the spherical body 3 from the cup.
It is essential that the fingers be enabled to withstand the forces being transferred at the mast foot and that they be elastic enough to permit that the cup portion 2 be shifted over the spherical portion 3 in which operation the cup opening 15 becomes elastically enlarged. When now the joint is in its inserted assembled condition, the fingers on the cup portion closingly and firmly embrace the spherical portion and maintain it in position like a solid seat.
It is possible that the spherical portion 1 be connected to the mast, whereas the cup portion 2 be connected to the boat body as shown in FIG. 8.
The mast footing arrangement brought in by the invention makes possible to have tied one portion of the joint firmly and the other portion of this joint rotarily to the boat body or to the mast, or to have both the portions lodged turnably in the mast and the boat body. The rotatable connection of one or both portions of the joint to the boat body and/or to the mast may be performed as shown in FIG. 6, e.g. by means of the rings 17 embedded in the grooves 18. The insertion of the joint may be performed after tackeling of the boat.
In this way, the invention provides a specifically simply constructed joint for the mast footing arrangement, where both the parts of the joint may be produced as plastic material injection or press formed parts. In this case, the swaying capacity proves to be at the optimum and in addition thereto, the mast may be attached so as to be rotatable.
It is self-speaking that it also is possible to have at least one portion of the joint equipped instead of the bolt with a per-se known bridging member and to have the same engaged in a corresponding cavity in the mast or in the boat body. Also the rounded areas of the joint of this invention exclude any danger of injury.
The fixation arrangement according to this invention reposes on the nut 22 and on the treadings 21 and 23. At the end of the bolt 10, there is engaged therewith a per-se known cylindrical mast attachment piece 25 provided with a bore 26 conformed to the bolt 10 and with an annular abutting edge 28. The mast attachment piece is introduced into the hollow region 27, so that the terminal edge 29 of the mast 27 abuts the abutting edge 28.
The mast and the mast attachment piece are connected to one another for having the joint inseparably tied to the mast, in order to attain a firmly unifying hold of the entire mast footing arrangement.
There are many cases in which it will be purposeful to free the joint quickly from the mast attachment piece, namely also, when the latter sticks to the mast. According to the invention, for achieving this, the terminal section of the bolt 10 is cut to form at least one slot 30 extending axially, thus being formed bolt tines 31 which are provided with border flanges 32 reaching beyond the bore 26. Preferably, the border flanges 32 possess outer bevellings 33, while the inner edge of the mast attachment piece 25 adjacent the border flanges 32 is provided with a corresponding bevelling 34 too. Furthermore, it is advantageous for the biasing operation of the bolt tines 31 when the bolt 10 includes a bore 35.
The function of the fixation arrangement provided by this invention is as follows:
For the mounting assemblage, the bolt 10 carrying on the nut 22 is inserted into the bore 26 of the mast attachment piece 25. During this operation, the biasing bolt tines 31 are radially depressed inwardly. This may be done manually or is produced thanks to the bevelling 33, whose inner edge is for this purpose preferably positioned within the range of the annular opening of the bore 26, so that the edge of the bore 26 can slide on the bevelling 33 and is enabled so to radially press together the bolt tines 31. On being introduced, the bolt tines 31 tend to bias back to their starting positions, when the border flange 32 arrives beyond the bore 26. The operative conditions are chosen so that this snapped connection either absolutely can not or hardly can be effectively disengaged manually. For this reason, there is the nut 22 which is serviceable for the separation. The same is turned and thus exerts pressure onto the mast attachment piece 25 which then impacts the entrance surface 36 and forces it against the border flange 32. In effect hereof the bolt tines 31 are radially moved due to a levering actuation, so that the outer edge of the border flange 32 slides in its lower area along the inner edge of the annular surface 34 and the joint tines 31 become elastically shifted radially to one another and the border flange 32 glides into the bore 26. This operation is substantially eased by a slight bevelling 34 on the mast attachment piece 25. All this led to the achievement that under application of few means there is obtained an efficient snapping interconnection that can not be manually disengaged, but can be provided by actuation of the nut 22 capable of exerting a substantially greater force apt to provide this disengagement.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in an articulate mast footing arrangement, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. | A connecting arrangement for connecting two elements with one another, particularly a mast and a boat body of a wind surfboard comprises a male member connected with one of the elements, and a female member engageable with the male member with snap action and connected to another of the elements. At least one of the members connected with a respective one of the elements is rotatable within the horizontal plane. Preferably, this one member is rotatable within the range of 360°. The male member and the female member together form a spherical joint. The male member may include a bolt section and a sperical section connected therewith whereas the female member may include a bolt portion and a cup portion connection therewith and adapted to receive the spherical section of the male member therein. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority from German Application No. 10 2007 028 019.1 filed Jun. 19, 2007, the content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the technical field of plant protection compositions which can be used against undesirable plant growth and which comprise, as active substances, a combination of at least two herbicides.
2. Description of Related Art
More especially, it relates to herbicidal combinations for use in rice which comprise, as active substances, a herbicide selected from the group consisting of benzoylcyclohexanediones in combination with at least one additional herbicide.
Herbicides from the abovementioned group of benzoylcyclohexanediones are known from numerous documents. Thus, for example, the herbicidal action of numerous such compounds is described in WO 00/21924. Some of the benzoylcyclohexanediones mentioned therein exhibit a satisfactory herbicidal action against harmful plants occurring in rice crops.
However, in practice, there are frequently disadvantages associated with use of the benzoylcyclohexanediones known from these documents. Thus, the herbicidal activity is not always satisfactory or, with a satisfactory herbicidal activity, undesirable damage to the rice plants is observed.
The effectiveness of herbicides depends, inter alia, on the type of herbicide used, the application rate thereof, the composition, the harmful plants to be combated each time, the climatic and soil conditions, and the like. A further criterion is the duration of the action or the rate of degradation of the herbicide. Changes in the sensitivity of harmful plants to an active substance which may occur with relatively long use or in geographically restricted areas are also to be taken into account, if appropriate. Such changes are expressed as a more or less serious loss in activity and can only to a limited extent be compensated for by higher herbicide application rates.
Because of the multitude of possible influencing factors, there is virtually no individual active substance which combines in itself the properties desired for different requirements, in particular with regard to the harmful plant species and the climatic zones. In addition, there is the constant problem of achieving the effect with an ever lower herbicide application rate. A lower application rate reduces not only the amount of an active substance required for the application but generally also reduces the amounts of formulation auxiliaries necessary. Both reduce the economic cost and improve the ecological compatibility of the herbicide treatment.
One method frequently used for improving the application profile of a herbicide consists in combining the active substance of one or more other active substances which contribute the additional properties desired. However, the combined use of several active substances not infrequently results in phenomena of physical and biological incompatibility, e.g. lack of stability of a combined formulation, decomposition of an active substance or antagonism of the active substances. On the other hand, what is desired are combinations of active substances with a favorable activity profile, high stability and the greatest possible synergistically strengthened activity which makes possible a reduction in the application rate in comparison with individual application of the active substances to be combined.
WO 02/089582 and WO 02/085118 describe herbicidal mixtures of particular benzoyl-1,3-cyclohexanediones with various herbicides. WO 02/085120 describes herbicidal mixtures of particular benzoyl-1,3-cyclohexanediones with safeners. However, in practice, there are serious disadvantages to these mixtures. Thus, their compatibility with regard to useful plants, in particular rice, is not always satisfactory and their activity with regard to harmful plants is likewise not always satisfactory.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide herbicidal combinations, in particular for use in rice crops, with improved properties in comparison with the state of the art.
The invention relates to herbicidal combinations, which comprise an effective amount of
A) the compound tembotrione and also the salts thereof normally used in agriculture (component A), B) a compound selected from the group consisting of benzobicyclon, pyrazolynate, sulcotrione, tefuryltrione and bromobutide (component B), and C) if appropriate, the safener isoxadifen-ethyl (component C).
The invention likewise relates to herbicidal combinations, which comprise an effective amount of
A) the compound tembotrione and also the salts thereof normally used in agriculture (component A), B) at least two compounds selected from the group consisting of tefuryltrione, cyhalofop-butyl, fenoxaprop-P-ethyl, fenoxaprop-ethyl, bensulfuron-methyl, ethoxysulfuron, fentrazamide and pyrimisulfan (component B), and C) if appropriate, the safener isoxadifen-ethyl (component C).
The invention further relates to herbicidal combinations, which comprise an effective amount of
A) the compound tefuryltrione and also the salts thereof normally used in agriculture (component A), B) at least two compounds selected from the group consisting of cyhalofop-butyl, fenoxaprop-P-ethyl, fenoxaprop-ethyl, bensulfuron-methyl, ethoxysulfuron and fentrazamide (component B), and C) if appropriate, the safener isoxadifen-ethyl (component C).
DETAILED DESCRIPTION OF THE INVENTION
The combinations according to the invention comprise the components A, B and C in a weight ratio of a:b:c, in which a and b can assume, in each case independently of one another, values of from 1 to 200, preferably 1 to 100, and c can assume a value of from 0 to 200, preferably 0 to 100.
The terms “component A”, “herbicide A” and “active substance A” are to be understood as synonymous in the context of the present description. The same applies for the terms “component B”, “herbicide B” and “active substance B” and also “component C”, “safener C” and “active substance C”.
In the combinations according to the invention, it is generally necessary to have application rates in the range from 10 to 1000 g, preferably 10 to 500 g, of active substance per hectare (ai/ha) of the component A and 1 to 1000 g, preferably 5 to 500 g, of the component B. Component C is normally used in an application rate in the range from 0 to 500 g, preferably 0 to 400 g, of active substance per hectare (ai/ha).
Optimum weight ratios can depend on the respective field of application, on the weed spectrum and on the active substance combination used and can be determined in preliminary experiments.
The active substances mentioned above with their common names are well known, for example from “The Pesticide Manual”, 14th edition, 2006, British Crop Protection Council, and the website “http://www.alanwood.net/pesticides/”. If, in the context of this description, the shortened form of the common name of an active substance is used, this each time includes all common routers, such as the esters and salts, and isomers, in particular optical isomers, in particular the commercially available form or forms. If an ester or salt is described by the common name, this also each time includes all other common derivatives, such as other esters and salts, the free acids and neutral compounds, and isomers, in particular optical isomers, in particular the commercially available form or forms. The chemical compound names given describe at least one of the compounds included under the common name, frequently a preferred compound.
Preference is given to herbicidal combinations comprising the combinations of active substances mentioned below:
tembotrione+benzobicyclon,
tembotrione+pyrazolynate,
tembotrione+sulcotrione,
tembotrione+tefuryltrione,
tembotrione+bromobutide,
tembotrione+benzobicyclon+isoxadifen-ethyl,
tembotrione+pyrazolynate+isoxadifen-ethyl,
tembotrione+sulcotrione+isoxadifen-ethyl,
tembotrione+tefuryltrione+isoxadifen-ethyl,
tembotrione+bromobutide+isoxadifen-ethyl;
tembotrione+tefuryltrione+fentrazamide,
tembotrione+tefuryltrione+cyhalofop-butyl,
tembotrione+tefuryltrione+pyrimisulfan;
tembotrione+tefuryltrione+fentrazamide+isoxadifen-ethyl,
tembotrione+tefuryltrione+cyhalofop-butyl+isoxadifen-ethyl,
tembotrione+tefuryltrione+pyrimisulfan+isoxadifen-ethyl;
tembotrione+bensulfuron-methyl+fentrazamide,
tefuryltrione+bensulfuron-methyl+fentrazamide,
tembotrione+ethoxysulfuron+cyhalofop-butyl,
tembotrione+ethoxysulfuron+fenoxaprop-P-ethyl,
tembotrione+ethoxysulfuron+fenoxaprop-ethyl,
tefuryltrione+ethoxysulfuron+cyhalofop-butyl,
tefuryltrione+ethoxysulfuron+fenoxaprop-P-ethyl,
tefuryltrione+ethoxysulfuron+fenoxaprop-ethyl;
tembotrione+bensulfuron-methyl+fentrazamide+isoxadifen-ethyl,
tefuryltrione+bensulfuron-methyl+fentrazamide+isoxadifen-ethyl,
tembotrione+ethoxysulfuron+cyhalofop-butyl+isoxadifen-ethyl,
tembotrione+ethoxysulfuron+fenoxaprop-P-ethyl+isoxadifen-ethyl,
tembotrione+ethoxysulfuron+fenoxaprop-ethyl+isoxadifen-ethyl,
tefuryltrione+ethoxysulfuron+cyhalofop-butyl+isoxadifen-ethyl,
tefuryltrione+ethoxysulfuron+fenoxaprop-P-ethyl+isoxadifen-ethyl,
tefuryltrione+ethoxysulfuron+fenoxaprop-ethyl+isoxadifen-ethyl.
The combinations according to the invention are very well suited to the selective combating of harmful plants in rice crops.
The combinations according to the invention can be used in all types of application normal for rice herbicides. They are particularly advantageously used in the spray application and in the submerged application. In the submerged application, the paddy water already covers the ground by up to 30 mm at the time of the application. The combinations according to the invention are then directly placed in the paddy water, e.g. in the form of granules. Worldwide, the spray application is used predominantly with seeded rice and the submerged application is used predominantly with transplanted rice.
The combinations according to the invention include a broad weed spectrum. They are suitable for example for the combating of annual and perennial harmful plants, such as, for example, from the species Abutilon, Alopecurus, Avena, Chenopodium, Cynodon, Cyperus, Digitaria, Echinochloa, Elymus, Galium, lpomoea, Lamium, Matricaria, Scirpus, Setaria, Sorghum, Veronica, Viola and Xanthium , in particular Echinochloa spp., Leptochloa spp., Scirpus spp., Cyperus spp., Sagittaria spp., Monochoria spp., Lindernia spp., Eleocharis spp. and Sesbania spp.
The herbicidal combinations according to the invention are also distinguished in that the effective dosages of the components A and B used in the combinations are reduced with regard to an individual dosage, so that a reduction in the necessary application rates of the active substances is rendered possible.
The herbicidal combinations according to the invention exhibit, in a preferred embodiment, synergistic effects with simultaneously high compatibility with regard to cultivated plants. The synergistic effects and the high compatibility with regard to cultivated plants can be observed, e.g., with combined application of the components A, B and C; however, it can also frequently be detected when the active substances are applied at different times (splitting). It is also possible to apply the individual herbicides and safeners or the herbicidal safener combinations in several portions (sequential application), e.g. pre-emergence applications, followed by post-emergence applications or early post-emergence applications, followed by medium or late post-emergence applications. Preference is given in this connection to the combined or virtually simultaneous application of the active substances of the herbicide combination according to the invention.
The synergistic effects allow a reduction in the application rates of the individual active substances, a greater potency at the same application rate, the control of species hitherto not included (gaps), an extension of the period of application and/or a reduction in the number of individual applications necessary and, as a result for the user, weed combating systems which are more advantageous economically and ecologically.
The invention also includes those herbicidal combinations which, in addition to the components A, B and C, if appropriate also comprise one or more additional agrochemical active substances with a different structure, such as herbicides, insecticides, fungicides or safeners. The preferred conditions explained above and below are likewise valid for such combinations. These additional agrochemical active substances can be applied both in the combinations according to the invention, as “ready mix”, and as “tank mix”, by jointly diluting the separately formulated or partially separately formulated components.
The invention likewise also in particular includes those combinations which, in addition to the components A, B and C, also comprise fertilizers, such as ammonium sulfate, ammonium nitrate, urea, potassium nitrate and mixtures thereof. The preferred conditions explained above and below are likewise valid for such combinations.
The invention furthermore also includes those combinations which, in addition to the components A, B and C, also comprise adjuvants, such as emulsifiers, dispersants, mineral and vegetable oils, and mixtures thereof. The preferred conditions explained above and below are likewise valid for such combinations.
The combinations according to the invention can exist both as mixed formulations of the herbicides A and B and also the safener C, if appropriate with additional conventional formulation auxiliaries, which are then used in the conventional way diluted with water, or be prepared as “tank mixes” by jointly diluting the separately formulated or partially separately formulated components with water or with aqueous solutions of fertilizers, for example such as mentioned above.
The combinations according to the invention are very well suited to combating harmful plants, in particular harmful plants in rice crops. Another subject matter of the invention is accordingly a method for combating undesirable plant growth, which comprises applying one or more of the combinations according to the invention to the harmful plants, plant parts thereof or the area under cultivation.
The components A, B and, if appropriate, C can be formulated in different ways, depending on which biological and/or chemical/physical parameters are specified. The following are possible, for example, as general formulation possibilities: wettable powders (WP), emulisifiable concentrates (EC), aqueous solutions (SL), emulsions (EW), such as oil-in-water and water-in-oil emulsions, sprayable solutions or emulsions, oil- or water-based dispersions, suspoemulsions, dustable powders (DP), seed dressings, granules for soil application or broadcasting, water-dispersible granules (WG), ULV formulations, microcapsules or waxes.
The individual formulation types are known in principle and are described, for example, in: Winnacker-Küchler, “Chemische Technologie” [Chemical Technology], Volume 7, C. Hauser Verlag, Munich, 4th edition, 1986; van Valkenburg, “Pesticide Formulations”, Marcel Dekker, N.Y., 1973; K. Martens, “Spray Drying Handbook”, 3rd Ed., 1979, G. Goodwin Ltd., London. The formulation auxiliaries necessary, such as inert materials, surfactants, solvents and additional additives, are likewise known and are described, for example, in: Watkins, “Handbook of Insecticide Dust Diluents and Carriers”, 2nd Ed., Darland Books, Caldwell, N.J.; H. v. Olphen, “Introduction to Clay Colloid Chemistry”, 2nd Ed., J. Wiley & Sons, N.Y.; Marsden, “Solvents Guide”, 2nd Ed., Interscience, N.Y., 1950; McCutcheon's, “Detergents and Emulsifiers Annual”, MC Publ. Corp., Ridgewood, N.J.; Sisley and Wood, “Encyclopedia of Surface Active Agents”, Chem. Publ. Co. Inc., N.Y., 1964; Schönfeldt, “Grenzflächenaktive Äthylenoxidaddukte” [Surface-active Ethylene Oxide Adducts], Wiss. Verlagsgesellschaft, Stuttgart, 1976; Winnacker-Küchler, “Chemische Technologie” [Chemical Technology], Volume 7, C. Hauser Verlag Munich, 4th Ed., 1986.
Based on these formulations, combinations with additional pesticidally active substances, such as other herbicides, fungicides or insecticides, and also safeners, fertilizers and/or growth regulators, can also be prepared, e.g. in the form of a ready mix or as tank mix.
Wettable powders are preparations which can be uniformly dispersed in water and which, in addition to the active substance, also comprise ionic or nonionic surfactants (wetting agents, dispersants), e.g. polyoxyethylated alkylphenols, polyethoxylated fatty alcohols or fatty amines, alkanesulfonates or alkylbenzenesulfonates, sodium lignosulfonate, sodium 2,2′-dinaphthylmethane-6,6′-disulfonate, sodium dibutylnaphthalenesulfonate or sodium oleoylmethyltaurinate, in addition to a diluent or inert substance.
Emulsifiable concentrates are prepared by dissolving the active substance in an organic solvent, e.g. butanol, cyclohexanone, dimethylformamide, xylene or also higher-boiling aromatic compounds or hydrocarbons, with addition of one or more ionic or nonionic surfactants (emulsifiers). Use may be made, as emulsifiers, for example, of: calcium alkylarylsulfonates, such as calcium dodecylbenzenesulfonate, or nonionic emulsifiers, such as fatty acid polyglycol esters, alkylaryl polyglycol ethers, fatty alcohol polyglycol ethers, propylene oxide/ethylene oxide condensation products, alkyl polyethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters or polyoxyethylene sorbitol esters.
Dustable powders are obtained by milling the active substance with finely divided solid materials, e.g. talc, natural clays, such as kaolin, bentonite and pyrophyllite, or diatomaceous earth.
Granules can be prepared either by spraying the active substance onto adsorptive granulated inert material or by applying active substance concentrates to the surface of carriers, such as sand or kaolinite, or of granulated inert material using binders, e.g. polyvinyl alcohol, sodium polyacrylate or else mineral oils. Suitable active substances can also be granulated in the standard way for the preparation of fertilizer granules, if desired as a mixture with fertilizers. Water-dispersible granules are generally prepared according to methods such as spray drying, fluidized-bed granulation, disk granulation, mixing with high-speed mixers and extrusion without solid inert material.
The agrochemical compositions generally comprise from 0.1 to 99 percent by weight, in particular from 0.2 to 95 percent by weight, of active substances A, B and, if appropriate, C, and also from 99.8 to 5 percent by weight of formulation agents customary in plant protection, the following concentrations being normal according to the type of formulation: in wettable powders, the active substance concentration is, e.g., from approximately 10 to 95 percent by weight, the balance for 100 percent by weight consisting of standard formulation constituents. With emulsifiable concentrates, the active substance concentration can be, e.g., from 5 to 80 percent by weight. Formulations in the form of dust for the most part comprise from 5 to 20 percent by weight of active substance, sprayable solutions from approximately 0.2 to 25 percent by weight of active substance. With granules, such as dispersible granules, the active substance content partly depends on whether the active compound is present in liquid or solid form and on which granulation auxiliaries and fillers are being used. With water-dispersible granules, the content is generally between 10 and 90 percent by weight. In addition, the active substance formulations mentioned comprise, if appropriate, the stickers, wetting agents, dispersing agents, emulsifying agents, preservatives, antifreeze agents, solvents, fillers, colorants, carriers, antifoaming agents, evaporation inhibitors, pH regulators or viscosity regulators which are standard in each case.
For use, the formulations existing in commercially available form are, if appropriate, diluted in the standard way, e.g. using water for wettable powders, emulsifiable concentrates, dispersions and water-dispersible granules. Compositions in the form of dusts, soil granules, granules for broadcasting and sprayable solutions are normally not diluted further with additional inert materials before use.
The active substances can be applied to the plants, plant parts, plant seeds or the area under cultivation (arable land), preferably to the green plants and plant parts and, if appropriate, additionally to the arable land.
One possibility of use is the joint application of the active substances in the form of tank mixes, where the concentrated formulations, which are optimally formulated, of the individual active substances are mixed together in a tank with water and the spray mixture obtained is applied.
A joint herbicidal formulation of the combination according to the invention of components A, B and, if appropriate, C has the advantage of being able to be applied more easily because the amounts of the components have already been adjusted to the correct ratio to one another. Moreover, the auxiliaries in the formulation can be optimally matched to one another, while a tank mix of different formulations can give undesirable combinations of auxiliaries.
A. Formulation Examples
a) A dustable powder (DP) is obtained by mixing 10 parts by weight of an active substance/active substance mixture and 90 parts by weight of talc as inert material and comminuting in a hammer mill.
b) A wettable powder readily dispersible in water (WP) is obtained by mixing 25 parts by weight of active substance/active substance mixture, 64 parts by weight of kaolin-comprising quartz as inert material, 10 parts by weight of potassium lignosulfonate and 1 part by weight of sodium oleoylmethyltaurinate as wetting and dispersing agent and milling in a pin mill.
c) A dispersion concentrate readily dispersible in water is obtained by mixing 20 parts by weight of an active substance/active substance mixture with 6 parts by weight of alkylphenol polyglycol ether (Triton X 207), 3 parts by weight of isotridecanol polyglycol ether (8 EO) and 71 parts by weight of paraffinic mineral oil (boiling range, e.g., approximately 255 to 277° C.) and milling in a friction ball mill to a fineness of less than 5 microns.
d) An emulsifiable concentrate (EC) is obtained from 15 parts by weight of an active substance/active substance mixture, 75 parts by weight of cyclohexanone as solvent and 10 parts by weight of oxyethylated nonylphenol as emulsifier.
e) A water-dispersible granule is obtained by mixing
75 parts by weight of an active substance/active substance mixture,
10 parts by weight of calcium lignosulfonate,
5 parts by weight of sodium lauryl sulfate,
3 parts by weight of polyvinyl alcohol and
7 parts by weight of kaolin
milling on a pin mill and granulating the powder in a fluidized bed by spraying on water as granulation liquid.
f) A water-dispersible granule is also obtained by homogenizing and precomminuting
25 parts by weight of an active substance/active substance mixture,
5 parts by weight of sodium 2,2′-dinaphthylmethane-6,6′-disulfonate,
2 parts by weight of sodium oleoylmethyltaurinate,
1 part by weight of polyvinyl alcohol,
17 parts by weight of calcium carbonate and
50 parts by weight of water
on a colloid mill, subsequently milling on a bead mill and atomizing and drying the suspension thus obtained in a spray tower using a single-substance nozzle.
B. Biological Examples
Post-Emergence Weed Action
Seeds or root pieces of harmful mono- and dicotyledonous plants are placed in sandy clay soil in pots, covered with earth and secured in a greenhouse under good growing conditions (temperature, air humidity, water supply). Approximately three weeks after sowing, the plants are treated at the 2- to 3-leaf stage with the herbicidal active substances or the combinations according to the invention. The combinations according to the invention formulated as wettable powders or as emulsion concentrates are sprayed, in spray application, on to the green plant parts in different dosages with a water application rate of 600 to 800 l/ha (corrected). Immediately up to a few days after application, the test receptacles accumulate water over the ground surface by up to 30 mm. With the water application (submerged application), on the other hand, the ground in the closed test receptacle is already covered with the paddy water up to 30 mm at the time of the application. The formulated active substances are here added directly to the paddy water. After an exposure time of the test plants in the greenhouse of an additional 3 to 4 weeks under optimum growing conditions, the effect of the preparations is evaluated visually in comparison with untreated controls. The combinations according to the invention exhibit, even in post-emergence, a very good herbicidal activity against a broad spectrum of economically important harmful plants. In this connection, actions of the combinations according to the invention which exceed the formal sum of the actions of the herbicides when applied individually are frequently observed. The values observed for the tests show, with suitable low dosages, an action of the combinations which lie above the expected values according to Colby.
When the combinations according to the invention are used, herbicidal actions on a harmful plant species which exceed the formal sum of the actions of the herbicides present when applied singly are frequently observed. Alternatively, it can in many cases be observed that a lower application rate for the herbicidal combination is needed in order to achieve, in comparison with the individual preparations, the same action with a harmful plant species. Such improvements in action or improvements in effectiveness or economies in application rate are a strong indication of a synergistic effect.
If the observed activity values already exceed the formal sum of the values for the tests with individual applications, then they likewise exceed the expected value according to Colby, which is calculated according to the following formula and is likewise regarded as an indication of synergy (cf. S. R. Colby in Weeds, 15 (1967), pp. 20 to 22):
E
=
A
+
B
-
A
×
B
100
In this connection:
A, B=action of the component A or B in percent at a dosage of a or b grams ai/ha, E=expected value in % at a dosage of a+b grams ai/ha.
The values observed for the test examples mentioned below are greater than (harmful plants) or lower than (cultivated plants) the expected values according to Colby.
The abbreviations are:
BRAPP
Brachiaria platyphylla
CYPES
Cyperus serotinus
ECHCG
Echinochloa crus galli
LEFCH
Leptochloa chinensis
SCPSS
Scirpus juncoides
ORYZA
Oryza sativa
TABLE 1
Herbicidal active substances
Compound
Compound
Compound
tembotrione: A1
tefuryltrione: A2
sulcotrione: B1
ethoxysulfuron: B2
cyhalofop-butyl: B3
fenoxaprop-P-ethyl: B4
benzobicyclon: B5
pyrazolynate: B6
bromobutide: B7
isoxadifen-ethyl: C1
TABLE 2
Post-emergence action
Dosage
Action/Damage
Compound
[g a.i./ha]
ORYZA
BRAPL
A1
12.5
10%
20%
B1
12.5
5%
0%
A1 + B1
12.5 + 12.5
10%
60%
Colby expected value:
24%
20%
Difference:
−58%
+200%
TABLE 3
Post-emergence action
Dosage
Action/Damage
Compound
[g a.i./ha]
ORYZA
BRAPL
A1 + B2
6.25 + 12.5
10%
20%
B3
6.25
0%
0%
A1 + B2 + B3
6.25 + 12.5 + 6.25
0%
50%
Colby expected value:
10%
20%
Difference:
−100%
+150%
TABLE 4
Post-emergence action
Dosage
Action/Damage
Compound
[g a.i./ha]
ECHCG
LEFCH
CYPES
A1 + B2 + B4
12.5 + 25 + 25
80%
40%
70%
C1
100
0%
0%
0%
A1 + B2 + B4 + C1
12.5 + 25 + 25 + 100
100%
88%
90%
Colby expected value:
80%
40%
70%
Difference:
+25%
+120%
+29%
TABLE 5
Post-emergence action
Dosage
Action/Damage
Compound
[g a.i./ha]
ORYZA
BRAPL
A2
62.5
10%
25%
B1
12.5
5%
0%
A2 + B1
62.5 + 12.5
10%
75%
Colby expected value:
24%
25%
Difference:
−58%
+200%
TABLE 6
Post-emergence action
Dosage
Action/Damage
Compound
[g a.i./ha]
ORYZA
LEFCH
A2 + B2
31.25 + 12.5
10%
55%
B3
6.25
0%
0%
A2 + B2 + B3
31.25 + 12.5 + 6.25
0%
75%
Colby expected value:
10%
55%
Difference:
−100%
+36%
TABLE 7
Post-emergence action
Dosage
Action against
Compound
[g a.i./ha]
SCPSS
A1
12.5
40%
A2
37.5
50%
A1 + A2
12.5 + 37.5
80%
Colby expected value:
70%
Difference:
+14%
TABLE 8
Post-emergence action
Dosage
Action against
Compound
[g a.i./ha]
SCPSS
A1
12.5
40%
B5
37.5
60%
A1 + B5
12.5 + 37.5
90%
Colby expected value:
76%
Difference:
+18%
TABLE 9
Post-emergence action
Dosage
Action against
Compound
[g a.i./ha]
SCPSS
A1
12.5
40%
B6
250
30%
A1 + B6
12.5 + 250
80%
Colby expected value:
58%
Difference:
+38%
TABLE 10
Post-emergence action
Dosage
Action against
Compound
[g a.i./ha]
SCPSS
A1
12.5
40%
B7
125
70%
A1 + B7
12.5 + 125
100%
Colby expected value:
82%
Difference:
+22%
TABLE 11
Post-emergence action
Dosage
Damage
Compound
[g a.i./ha]
ORYZA
A1 + A2 + B5
25 + 75 + 75
80%
C1
300
0%
A1 + A2 + B5 + C1
25 + 75 + 75 + 300
40%
Colby expected value:
80%
Difference:
−50%
TABLE 12
Post-emergence action
Dosage
Damage
Compound
[g a.i./ha]
ORYZA
A1 + A2 + B5
12.5 + 37.5 + 37.5
10%
C1
300
0%
A1 + A2 + B5 + C1
12.5 + 37.5 + 37.5 + 300
0%
Colby expected value:
10%
Difference:
−100% | Synergistic combinations are provided which are compatible with cultivated plants and which comprise herbicides selected from the group consisting of benzoylcyclohexanediones for use in rice crops
Herbicidal combinations are provided comprising bensulfuron-methyl, benzobicyclon, bromobutide, cyhalofop-butyl, ethoxysulfuron, fenoxaprop-P-ethyl, fentrazamide, pyrazolynate, pyrimisulfan, sulcotrione, tefuryltrione, tembotrione and, if appropriate, isoxadifen-ethyl are described. These combinations exhibit an effect which is superior to that of the herbicides used individually. | 0 |
FIELD OF THE INVENTION
The present invention relates to a lapping process for producing a nonwoven lap.
The present invention also relates to a nonwoven lapped product which can be obtained by means of the process.
The present invention relates, furthermore, to a stretcher/lapper for carrying out the process and for obtaining the product.
BACKGROUND OF THE INVENTION
Conventional stretcher/lappers are known, for example from DE-B-1,927,863, and in these an unwinding carriage executes transverse to-and-fro movements above an exit conveyor movable at a constant speed.
When the unwinding carriage is at either one of its ends of travel, it has to stop in order to change its direction of movement, while it continues to unwind the web onto the exit conveyor at an unchanged speed. However, since the relative speed between the carriage and the exit conveyor has decreased greatly since it no longer comprises the transverse component of the movement of the unwinding carriage, the web is unwound in excess. These traditional machines thus produce considerable lateral bolsters which subsequently have to be eliminated in order to obtain a product having per unit area a weight which is approximately uniform at all points of its width.
It is known from FR-B-2,234,395 to overcome these disadvantages, on the one hand, by imparting to the exit conveyor a speed which varies in proportion to the absolute value of the speed of the unwinding carriage, particularly in such a way that the exit conveyor is at a stop when the unwinding carriage is itself at a stop during its changes of direction of movement, and on the other hand by giving the feed carriage located upstream of the unwinding carriage a law of movement such that the unwinding carriage delivers the web at a speed which is itself proportional to the speed of the exit conveyor and to the absolute value of the speed of the unwinding carriage.
Thus, the quantity of web deposited per unit area of the exit conveyor is theoretically constant, and consequently the lapped product produced is theoretically perfectly uniform.
Moreover, as a result of the lapping operation, the initially longitudinal fibers of the web feeding the stretcher/lapper are arranged transversely in the lap at a particular angle of inclination, for example less than 15°. A result of this is that the tensile strength of the lap is much lower in the longitudinal direction of the lap than in its transverse direction which virtually coincides with the orientation of the fibers. This is a disadvantage because the lap is an intermediate product intended to undergo subsequent conversions, especially by needling, in the course of which it is pulled in its longitudinal direction. It is therefore in the longitudinal direction that the highest tensile strength would be desired. The poor tensile strength which has to be allowed for at the present time in order to conduct the needling or such like operations limits the working speed and brings about a transverse shrinkage during the needling, this shrinking tending to generate overthicknesses at the edges.
OBJECT OF THE INVENTION
The object of the present invention is to provide a lapping process, a lapped product and a stretcher/lapper which overcome these disadvantages and which make it possible, in particular, to produce in a very simple way a lapped product having a high longitudinal tensile strength.
SUMMARY OF THE INVENTION
According to the invention, the lapping process, in which an unwinding carriage is fed with a web comprising fibers directed substantially parallel to the length of this web, whilst this unwinding carriage is displaced in a to-and-fro movement above an exit conveyor, causing it to deposit the web on the exit conveyor driven in a direction which is transverse to the direction of movement of the unwinding carriage, so as to produce a lap consisting of successive breadths inclined once in one direction and once in the other in relation to the longitudinal direction of the exit conveyor, these breadths being joined by means of folds defining the edges of the lap produced, a process in which the advance of the exit conveyor at the moment of the change in direction of the movement of the unwinding carriage is maintained, is defined in that, at said moment, the quantity of web unwound by the unwinding carriage toward the exit conveyor is restricted so as to exert on the fibers, between the exit conveyor and the unwinding carriage, a pull tending to orient the fibers which form the folds of the web in the lap parallel to the longitudinal direction of the exit conveyor.
A kind of cord consisting largely of longitudinally oriented fibers is thus formed along the two longitudinal edges of the lap. These cords thus have a surprising tensile strength and for the subsequent processing, especially during needling, constitute a kind of tensile reinforcement which considerably reinforces the lap in respect of the deformations which tend to occur under the effect of the pull.
It is possible subsequently, for example after the needling operation, to eliminate the two lateral cords, of which the thickness, apparent density and structure do not conform to those of the rest of the lap.
Although this produces waste, nevertheless, surprisingly, this waste, accepted in principle in the process according to the invention, ultimately proves to be markedly less copious than that caused by many other processes which theoretically ought to produce no waste. The lateral strip to be cut off on each side of the lap can, for example, have a width of 50 mm according to the invention, instead of 150 mm in some known processes.
Furthermore, the invention makes it possible to minimize the transverse shrinkage during the needling, and consequently the needled product obtained has a better uniformity of weight.
According to a second subject of the invention, the nonwoven lapped product is defined in that it comprises, in its lateral edges, portions of fibers directed longitudinally and forming an obtuse angle with other portions of the same fibers directed obliquely toward the central part of the product.
According to a third subject of the invention, the stretcher/lapper, comprising transport means for defining a transport path of a web as far as an unwinding carriage movable in a to-and-fro movement above an exit conveyor movable transversely to the direction of the to-and-fro movement of the unwinding carriage, is defined by means for imparting to the exit conveyor a speed substantially proportional to the absolute value of the speed of the unwinding carriage, except within time intervals including the moments of change in direction of movement of the unwinding carriage, during which the speed of the exit conveyor is higher than that which would result from the calculation of proportionality in relation to the absolute value of the speed of the unwinding carriage, and by means for causing the web to be unwound by the unwinding carriage at a speed which is proportional to the speed of the exit conveyor, except within time intervals including the moments of change in direction of movement of the unwinding carriage, during which the unwinding speed is lower than that which would result from the calculation of proportionality in relation to the speed of the exit conveyor.
Other particular features and advantages of the invention will further emerge from the following description referring to a non-limiting example.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a perspective external view of a stretcher/lapper;
FIG. 2 is a diagrammatic elevation view of an example of a stretcher/lapper according to the invention;
FIG. 3 is an enlarged view of part of the view of FIG. 2;
FIG. 4 shows a graph illustrating the instantaneous speeds of various components of the stretcher/lapper; and
FIG. 5 is a perspective view illustrating the deposition of the web on the exit conveyor of the stretcher/lapper.
DETAILED DESCRIPTION OF THE INVENTION
A stretcher/lapper is shown in perspective in FIG. 1.
A first transporter conveyor 2, called a front transporter, takes up the fibre web 4, for example coming from a card (not shown), and transports it into the enclosure 1 of the stretcher/lapper, where it is converted by folding into a lap 6 of width L transported out of the stretcher/lapper by an exit conveyor 8. The web 4 consists of fibers essentially directed parallel to its length. The exit conveyor 8 can transport the formed lap 6 to a needler (not shown). The direction of transport of the web 4 and of the lap 6 are indicated in FIG. 1 by the respective arrows F and K. For reference purposes, the side 7 adjacent to the face by which the web 4 enters will be called the "front side" of the stretcher/lapper and the side 9 opposite the front side 7 the "rear side" of the stretcher/lapper.
The interior of the stretcher/lapper is shown diagrammatically in the elevation view of FIG. 2, taken in a plane Q (see FIG. 1) perpendicular to the direction of transport of the lap 6 out of the stretcher/lapper by the exit conveyor 8.
In addition to the front transporter 2, the stretcher/lapper comprises a second transporter conveyor 5, called a rear transporter. The transporters 2 and 5, represented by unbroken lines in FIG. 2, have the same width and have their lateral edges in the same planes parallel to the plane Q of FIG. 2. The front transporter 2 follows a closed path defined by cylindrical guide rollers 32 to 43. The rear transporter 5 follows a closed path defined by cylindrical guide rollers 60 to 69.
The guide rollers 32 to 43 and 60 to 69 are mounted pivotably about respective axes which are all horizontal and perpendicular to the plane Q of FIG. 2, that is to say substantially parallel to the direction of movement of the exit conveyor 8. These guide rollers 32 to 43 and 60 to 69 comprise rollers 32, 33, 39, 40, 42, 43 and 65, 66, 68, 69, the axis of which is stationary in relation to the frame 1 of the stretcher/lapper, rollers 34, 35 and 60, 61, 62, 63 carried by a first movable main carriage 10, called a feed carriage, rollers 36, 37, 38 and 64 carried by a second movable main carriage 14, called an unwinding carriage, and rollers 41 and 67 carried by auxiliary carriages 16, 18. The auxiliary carriages 16, 18 each carry a guide roller 41, 67 corresponding to one of the transporters 2, 5. The two auxiliary carriages 16, 18 have movements which compensate those of the main carriages 10, 14 in order to keep constant the length of each of the closed paths followed by the transporters 2, 5. Between the main carriages 10, 14 and the auxiliary carriages 16, 18, the transporters 2, 5 are guided by rollers of stationary axis located on the sides 7, 9 of the stretcher/lapper on either side of the exit conveyor 8.
The main carriages 10, 14 are located above the exit conveyor 8 and are movable in translation in a horizontal direction perpendicular to the axes of the rollers 32 to 43 and 60 to 69.
During operation, the main carriages 10, 14 are displaced in this direction in a to-and-fro movement.
A first notched belt 84, represented by dashes in FIG. 2, has its ends fastened to the feed carriage 10 and to the first auxiliary carriage 16. The notched belt 84 is guided between these two carriages 10, 16 by pinions 85, 86 located on the rear side 9 of the stretcher/lapper. Moreover, these two carriages 10, 16 are coupled by means of a cable 92, represented by dot-and-dashed lines in FIG. 2, passing through the front side 7 of the stretcher/lapper and guided by pulleys 93, 94. The pinion 86 meshing with the notched belt 84 is driven by a motor 24. When the motor 24 drives the pinion 86 in a first direction, the feed carriage is drawn toward the rear side 9 of the stretcher/lapper, with the result that, by means of the cable 92, the associated auxiliary carriage 16 is drawn at the same speed toward the front side 7 of the stretcher/lapper. When the motor 24 drives the pinion 86 in the other direction, the auxiliary carriage 16 is drawn toward the rear side 9 of the stretcher/lapper, with the result that, by means of the cable 92, the feed carriage 10 is drawn at the same speed toward the front side 7 of the stretcher/lapper.
A similar assembly is provided for driving the unwinding carriage 14 and its associated auxiliary carriage 18. A second notched belt 88, represented by dashes in FIG. 2, has its ends fastened to the unwinding carriage 14 and to the auxiliary carriage 18. The notched belt 88 passes through the front side 7 of the stretcher/lapper, going round two pinions 89, 90. Moreover, these two carriages 14, 18 are coupled by means of a second cable 96, represented by dot-and-dashed lines in FIG. 2, passing through the rear side 9 of the stretcher/lapper and guided by two pulleys 97, 98. The pinion 90 meshing with the notched belt 88 is driven in rotation by a motor 25. When the motor 25 drives the pinion 90 in a first direction, the unwinding carriage 14 is drawn toward the front side 7 of the stretcher/lapper, with the result that, by means of the cable 96, the associated auxiliary carriage 18 is drawn at the same speed toward the rear side 9 of the stretcher/lapper. When the motor 25 drives the pinion 90 in the other direction, the auxiliary carriage 18 is drawn toward the front side 7 of the stretcher/lapper, with the result that, by means of the cable 96, the unwinding carriage 14 is drawn at the same speed toward the rear side 9 of the stretcher/lapper.
The travel of the front transporter 2 along its closed path is provided by a motor 26 which drives one of the guide rollers 43 of the front transporter 2 in rotation. Likewise, the travel of the rear transporter 5 along its closed path is provided by a motor 27 which drives one of the guide rollers 65 passed round by the rear transporter 5 in rotation.
As can be seen in FIG. 2 and in the more detailed view in FIG. 3, the web 4 is delivered to the feed carriage 10 by the front transporter 2. On the feed carriage 10, the web 4 executes a 180° turn in order to enter a nip zone 23, in which it is held between the two transporters 2, 5. The nip zone 23 terminates at the unwinding carriage 14 which deposits the web 4 on the exit conveyor 8.
The to-and-fro movement of amplitude L of the unwinding carriage 14 ensures that the web 4 is deposited on the exit conveyor 8 in alternate folds, so as to form a lap 6 consisting of successive breadths of web. Since the exit conveyor 8 driven by a motor 28 is displaced perpendicularly to the direction of movement of the unwinding carriage 14, the successive breadths of web are inclined once in one direction and once in the other in relation to the longitudinal direction of the exit conveyor 8. The alternate folds which join the breadths to one another are therefore offset relative to the longitudinal direction of the lap 6 and define its lateral edges (see FIG. 5).
The kinematic laws applied by the various motive means of the stretcher/lapper, namely the drive motor 24 of the feed carriage 10, the drive motor 25 of the unwinding carriage 14, the motor 26 for the travel of the front transporter 2, the motor 27 for the travel of the rear transporter 5 and the drive motor 28 of the exit conveyor 8, will now be described.
The motors, 24, 25, 26, 27, 28 can be controlled independently, for example electronically, in order to apply these kinematic laws. Alternatively, suitable transmission mechanisms can be provided, in order to obtain the desired speed dependencies between the various movable parts (one example of this type of mechanism is provided in FR-B-2,234,395).
Referring to FIG. 3, v denotes the delivery speed of the web 4 at the entrance of the stretcher/lapper, u the algebraic speed of the feed carriage 10 and w the algebraic speed of the unwinding carriage 14. The delivery speed v of the web 4 is always counted as positive and algebraic speeds u, w of the carriages 10, 14 are counted as positive in the direction indicated in FIG. 3, in which the carriages 10, 14 are displaced in a direction identical to the direction of delivery of the web 4, and as negative in the opposite direction. The speed v, which is generally constant, is imposed by the output of the card located upstream of the stretcher/lapper. The speed u and w are imparted respectively by the motors 24 and 25.
The motor 26 for the travel of the front transporter 2 is set so as to impart to it a speed equal to the speed v in the sections where it receives the web 4 upstream of the feed carriage 10. The motor 27 for the travel of the rear transporter 5 is set so as to impart to it a speed x (see FIG. 3) equal to v-2u upstream of the feed carriage 10, in such a way that the two transporters 2, 5 have the same speed in the nip zone 23.
Under these conditions, the speed y of unwinding of the web 4 by the unwinding carriage 14 toward the exit conveyor 8 is equal to x+w=v-2u+w.
FIG. 5 shows the speed z imparted to the exit conveyor 8 by its drive motor 28.
FIG. 4 shows examples of timing diagrams for the speeds u, w, x and z which can be imparted respectively by the motors 24, 25, 27 and 28 (the constant timing diagram of the speed v imparted by the motor 26 has not been shown). FIG. 4 also shows, by dashes, the timing diagram of the unwinding speed y resulting from the speeds imparted by the various motors.
The speed w of the unwinding carriage 14, represented by a thick line in FIG. 4, obeys a periodic law alternating as a function of the time t, each alternation corresponding to a breadth of the lap 6 formed on the exit conveyor 8. The speed w can, for example, obey a sine law. In the example illustrated, the unwinding carriage 14 has a brief stopping time of duration d at the moment of its change in direction.
The drive motor 24 of the feed carriage 10 is set in such a way that its speed u satisfies the following relations (the curve represented by an unbroken line in FIG. 4):
u=w+v/2 when w<0
u=v/2 when w≧0
The motor 27 is then set so that it drives the rear transporter 5 at a speed x=v-2u, the curve of which is drawn in the form of dots in FIG. 4. Under these conditions, the unwinding speed y of the web 4 is equal at each moment to the absolute value of the speed w of translation of the unwinding carriage 14. It will be noted that the unwinding of the web 4 is interrupted (y=0) during the stopping times d corresponding to the changes in direction of the unwinding carriage 14.
The motor 28 is set so that the instantaneous speed z of the exit conveyor 8 is proportional to the unwinding speed y of the web 4 and therefore proportional to the absolute value of the speed w of the unwinding carriage, the ratio a=z/|w|=z/y defining the mean angle between the fibers of each breadth of the deposited web and the transverse direction of the lap 6. However, during a short time interval D including each stopping time d of the unwinding carriage 14, the motor 28 imparts to the exit conveyor 8 a non-zero speed z, that is to say a speed which is higher than that which would result from the calculation of proportionality to the speed y according to the ratio a. The advance of the exit conveyor 8 is therefore uninterrupted even at the moments of the changes in direction of the movement of the unwinding carriage 14. In other words, during the time intervals D, the quantity of web 4 unwound by the unwinding carriage 14 toward the exit conveyor 8 in relation to the speed z of the exit conveyor 8 is restricted. Thus, at the moments of the changes in direction of movement of the unwinding carriage 14, a pull is exerted on the fibers between the exit conveyor 8 and the unwinding carriage 14 and tends to orient the fibers which form the folds of the web at the edges of the lap 6 parallel to the longitudinal direction of the exit conveyor 8.
FIG. 5 illustrates diagrammatically the non-woven lapped product 6 obtained on the exit conveyor 8 and shows the unwinding carriage 14 at the moment when it changes direction above one edge of the lap 6. At this moment, the speed z of the exit conveyor 8 is non-zero and the unwinding of the web 4 is restricted or interrupted (y=0). The lateral edges of the lap 6 then comprise portions of fibers oriented substantially longitudinally and forming an obtuse angle with other portions of the same fibers contained in breadths of web inclined and directed obliquely toward the central part of the lap 6.
On account of these portions of fibers oriented longitudinally, the lapped product 6 has a satisfactory longitudinal tensile strength. Furthermore, during a subsequent needling, it will experience an advantageously reduced transverse shrinkage.
Although a specific exemplary embodiment of the present invention has been described, it will be noted that various modifications can be made to it, without departing from the scope of the invention.
Thus, an example, in which the unwinding speed y of the web 4 is at each moment equal to the absolute value of the speed w of displacement of the unwinding carriage 14, has been described. According to the invention, it is generally preferable for this unwinding speed y to be proportional to |w|, the instance of equality described being only one particular example in which the proportionality ratio is 1.
Moreover, it will emerge clearly to a person skilled in the art that the process according to the invention can be carried out with stretcher/lappers different from that described by way of example with reference to FIGS. 1 to 3. | An unwinding carriage (14) is fed with a fiber web (4). This unwinding carriage (14) is displaced in a to-and-fro movement, causing it to deposit the web (4) on an exit conveyor (8) driven transversely to the movement of the unwinding carriage (14), so as to produce a lap (6) consisting of successive breadths of web inclined alternately in relation to the longitudinal direction of the exit conveyor (8), these breadths being joined by means of folds defining the edges of the lap produced (6). The advance of the exit conveyor (8) at the moments of the changes in direction of the unwinding carriage (14) is maintained. During these changes in direction, the unwound quantity of web (4) is restricted so as to exert on the fibers, between the exit conveyor (8) and the unwinding carriage (14), a pull tending to orient the fibers which form the folds of the web in the lap (6) parallel to the longitudinal direction of the exit conveyor (8). The invention is used particularly for making needled products. | 3 |
BACKGROUND
In a printer or other type of paper handler, the paper or medium may move through the printer along a media path using a combination of belts and rollers. Various arrangements of belts and rollers may wrinkle or otherwise damage the paper. In other instances, the belts and rollers may contact freshly-printed surfaces and damage the printed image.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a conceptual illustration of a printer according to embodiments of the invention;
FIG. 2 is a block diagram of the workflow of a printer according to embodiments of the invention;
FIG. 3 is a conceptual illustration of a drying area of a printer according to embodiments of the invention;
FIG. 4 is a conceptual illustration of a roller assembly of a printer according to embodiments of the invention;
FIG. 5 is a conceptual illustration of a conical roller in a roller assembly of a printer according to embodiments of the invention; and
FIG. 6 is a magnified view of part of a roller assembly and a belt within a printer according to embodiments of the invention.
Where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.
DETAILED DESCRIPTION
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention. However, it will be understood by those of ordinary skill in the art that the embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the present invention.
Embodiments of the present invention may be used in a variety of applications. Although the present invention is not limited in this respect, the techniques disclosed herein may be used in paper handling machines such as inkjet and laser printers, photo printers, multi-function printers, copiers, presses, and the like.
Printed images or impressions on a freshly-printed surface on a medium (such as paper or cards) may be damaged by rollers used to advance or guide the medium through the printer. Embodiments of the invention may provide an apparatus and techniques that minimize such damage. Such embodiments may include a roller assembly having a set of conical rollers that are tapered such that the paper may be contacted just at the edges.
Reference is now made to FIGS. 1 and 2 , which are, respectively, a conceptual illustration of a printer 100 and a block diagram of the workflow of the printer according to embodiments of the invention. Printer 100 may include input area 10 , printing area 40 , drying area 60 , and output area 90 , among other areas. Medium 5 may be fed into input area 10 , in which there may be one or more rollers 12 . Printing, imaging, or otherwise making an impression onto medium 5 may occur in printing area 40 . Printing area 40 may include imager 45 , which may be a drum, one or more ink cartridges attached to a belt drive, or ink cartridges providing ink to a carriage, depending upon which type of printer 100 is, e.g. an inkjet printer, a photo printer, a laser printer, a copier, a multi-function printer, etc. Medium 5 is fed or guided along media path 7 to drying area 60 and then may exit the printer through output area 90 , which may include one or more rollers 92 .
The parts and blocks shown in FIGS. 1 and 2 are examples of parts that may comprise printer 100 and its workflow, and do not limit the parts or modules that may be part of or connected to or associated with printer 100 .
A conceptual illustration of drying area 60 is shown in FIG. 3 . Freshly-printed medium 5 may exit printing area 40 and may be guided in between roller assembly 70 and belt 65 from left to right in FIG. 3 . Belt 65 may advance using rollers 62 , 64 . Roller assembly 70 , shown in more detail in FIG. 4 , may include shaft or axle 74 and conical rollers 72 . Belt 65 may be a flat conveyor belt, which may be minimally tensioned such that low normal force may cause the belt to deflect. Belt 65 may be an endless belt formed from a continuous band, or a straight piece with its two ends joined together.
Reference is now made to FIG. 4 , which is a conceptual illustration of roller assembly 70 guiding medium 5 according to embodiments of the invention. Conical rollers 72 may be disposed near the ends of shaft 74 and typically are fixed with respect to the shaft (i.e., they do not move parallel or along shaft 74 ). Since rollers 72 are conical, they are tapered such that each one nominally contacts medium 5 at one place—the edge of the medium, not on the freshly-printed surface itself. (This may be seen more clearly in FIG. 6 .) Conical rollers 72 may be designed to be placed on the shaft so that their centers C are as far apart as the typical width of medium 5 , for example 4 inches (10 cm) for a 4″×6″ photo card, or 8.5 inches (˜21.25 cm) for 8.5″×11″ letter-sized paper. Roller assembly 70 may then be effective at guiding media having a range of widths such that both media edges are capable of contacting the rollers.
Roller assembly 70 can guide medium 5 in two typical types of printer arrangements—edge-justified and center-justified. Justification refers to the position of the medium relative to the printer's media path as the medium travels through the printer. Edge-justified refers to a medium traveling though the printer contacting a guide on one edge. Center-justified refers to a medium that travels through the printer centered between the edges of the printer. In center-justified printers, roller assembly 70 can help to self-center medium 5 while it travels through printer 100 .
Typically, the image on the medium as it exits printing area 40 may still be wet. Thus, even though conical rollers 72 nominally contact medium 5 at the edges, it is advantageous to use non-stick roller material, at least on the outer surface of the roller. Several Teflon®-based materials are good for this: Teflon® itself (polytetrafluoroethylene or “PTFE”), Teflon-FEP, sometimes called simply “FEP” (for fluorinated ethylene propylene), and Teflon-PFA, sometimes called simply “PFA” (for perfluoroalkoxy). Teflon-FEP and PFA are also easy to injection mold into rollers. Delrin® (polyoxymethylene, also known as “POM,” polyacetal, or polyformaldehyde), made by DuPont, is less expensive than Teflon®-based materials, is relatively non-stick, and can be injection molded into rollers. These materials are listed in descending order of non-stickiness.
Reference is now made to FIG. 5 , which is a conceptual illustration of conical roller 72 in roller assembly 70 . The taper angle can help to handle various media types and to self-center the medium. An angle θ˜5-10° is shown in FIG. 5 ; typical taper angles may range from 5° to 40°, with a preferred range of 10° to 30°. Having a larger taper angle allows the roller assembly to center and guide the medium better, but also tends to bend the medium more. Thus, larger taper angles may be better suited for stiffer media such as card stock and photo paper, and smaller cone angles may be better suited for more flexible media, such as paper. Also, selecting a flatter cone profile (smaller taper angle) allows the printer to feed various media widths without requiring any machine reconfiguration.
Reference is now made to FIG. 6 , which is a magnified view of part of roller assembly 70 and belt 65 . As described earlier, belt 65 may be placed under roller assembly 70 , allowing medium 5 to be guided in between roller assembly 70 and belt 65 . Belt 65 may be made of urethane, reinforced with polyester (or similar) manmade fibers. In some embodiments, belt 65 is not needed and is not included in printer 100 , in which case conical rollers 72 may guide the medium.
If belt 65 is included in printer 100 , one consideration in using it is the tension of the belt, which may typically be 15 to 20 Newtons. A low tension allows the medium to wander either left or right without excessive pinching or binding of the medium, which may result in damage to the freshly-printed surface. As the medium moves to the right side of the printer (see arrow 78 ), it may tend to get pushed further into the flat belt due to the conical roller. Because the belt may be set to a very low tension, it is sufficiently compliant such that the belt can move out of the way (see arrows 68 ) and minimize detrimental effects to the photo surface due to what could otherwise be excessive pinch force. The opposite effect may be true if the medium tends to move to the left side of the printer. A printer having flat rollers rather than conical rollers may not be capable of operating in this fashion.
If belt 65 is included in printer 100 , another consideration may be where to place roller assembly 70 in relation to belt 65 . If roller assembly 70 is located near rollers 62 or 64 , there may too much resistance and not enough compliance. Locating the roller assembly toward the middle of the belt allows the roller assembly to move up and down more easily. Typical placement of roller assembly 70 in terms of belt length L may be one-quarter or one-third L (also called one-quarter or one-third span), or even one-half L (roller assembly 70 would be in the middle of the belt).
In sum, a roller assembly for use in printer is described that may be used to guide a freshly-printed medium through a printer without damaging the printed image. This may be accomplished by using conical rollers, which may be made of a non-stick material, that contact the medium only by the edges. The conical roller assembly may also self-center the medium as it travels through the printer, and is able to accommodate a range of media weights and widths.
The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. | A roller assembly for use in a printer includes a shaft with two ends and a pair of conical rollers. Each of the conical rollers is disposed on the shaft near each of the ends. The roller assembly guides a medium within the printer without damaging a freshly-printed surface of the medium. A printer including the roller assembly and a belt in contact with the roller assembly is also described and claimed. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to an apparatus for engaging and disengaging a vehicle's park brake through hydraulic and electrical actuation rather than by mechanical actuation by the vehicle operator.
[0003] 2. Description of the Prior Art
[0004] In an automatic transmission that employs a shift-by-wire (SBW) control Park, Reverse, Neutral and Drive ranges of the transmission are engaged and disengaged under electrical control. SWB systems have begun to replace the conventional shifter cable, which is used in automatic transmissions to control the park pawl and a hydraulic manual valve that feeds pressure to clutches that distinguishes the Neutral range from the Reverse and Drive ranges.
[0005] SBW systems generally are of two types: (i) electromechanical having redundant hardware and supplemental power, and (ii) electro-hydraulic having a redundant electro-mechanical path. Electro-hydraulic SBW systems allow for reduced cost, but generally do not cover unintended loss of the Park function with single point failures.
SUMMARY OF THE INVENTION
[0006] A vehicle park-brake system includes a park brake, a solenoid; a first pressure source; a servo for disengaging the park-brake using the first pressure source, and for disengaging the park-brake using a force produced by the solenoid that actuates first and second pistons; and a second pressure source applied to the servo causing hydraulic pressure to vent from the servo, the pistons to detach mutually, and the servo to engage the park brake.
[0007] The system has secondary control of park, which allows for park re-engagement, if the primary control fails to function.
[0008] The system does not permit loss of park-engagement due to a single point failure. Using a latch valve from one of the transmission clutches, allows park-engagement, if an error state occurs. The system has a decoupling feature that allows for park-engagement, if the electro-mechanical solenoid fails in the latch position.
[0009] The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art.
DESCRIPTION OF THE DRAWINGS
[0010] The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which:
[0011] FIG. 1 is a block diagram showing the components of a shift-by-wire system that control the selection of drive ranges of an automatic transmission; and
[0012] FIG. 2 is schematic diagram of the SBW system of FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] The SBW system 10 of FIG. 1 includes a latch valve 12 for a low-reverse clutch, i.e., a clutch that must be engaged hydraulically for a motor vehicle's automatic transmission to produce first gear or reverse gear; park control valve 14 ; park servo 16 ; solenoid 17 ; electro-hydraulic on-off solenoid 18 ; electro-mechanical on-off solenoid 20 ; and electro-hydraulic on-off solenoid 22 .
[0014] Solenoid 17 opens a connection between a source of line pressure 28 and line 32 when valve 12 is latched by control pressure in line 19 , i.e., when the low-reverse clutch is engaged, and closes that connection when valve 12 is unlatched. Solenoid 18 shuttles the park control valve 14 using pressure in hydraulic line 26 . A source of line pressure 28 is connected through hydraulic line 30 to the latch valve 12 . Latch valve 12 communicates hydraulically with park control valve 14 through hydraulic line 32 .
[0015] Solenoid 20 holds the park servo 16 out of its Park position. Displacement of park servo 16 disengages a park assembly 34 , against resistance force produced by a spring 36 , which force urges the park assembly 34 into its park position. Park control valve 14 communicates hydraulically with park servo 16 through hydraulic line 38 .
[0016] Solenoid 22 is supplied with fluid through line 40 from the outlet of an e-pump 24 , which is driven by an electric motor with electric energy from the vehicle's battery 25 and supplied with fluid from a sump 41 . Solenoid 22 opens and closes a hydraulic connection through hydraulic line 42 between the e-pump 24 and park servo 16 .
[0017] FIG. 2 shows that latch valve 12 includes a valve spool 50 , located in a cylinder bore 52 ; a line pressure port connected by line 30 to the source of line pressure 28 ; an exhaust port EX communicating with the bore; and a port connected to line 32 .
[0018] Park control valve 14 includes a valve spool 54 , located in a cylinder bore 56 ; a spring 57 urging spool 54 leftward; a port connected by line 32 to latch valve 12 ; an exhaust port EX communicating with cylinder bore 56 ; and a port connected to line 38 . Solenoid 18 opens and closes control pressure supplied to cylinder bore 56 through line 26 .
[0019] Park servo 16 includes a cylinder 58 , a first piston 60 located in cylinder 58 and connected mechanically to a crank arm 62 , whose angular position about an axis 64 is affected by torsion spring 36 ; an park rod 66 mechanically connected to park pawl 68 , which pivots about axis 69 into and out of engagement with a parking gear (not shown); a second piston 70 located in cylinder 58 and releaseably connected by a detent 72 to the first piston 60 ; a port communicating line 38 to cylinder 58 ; and a port communicating cylinder 58 to line 42 . Solenoid 20 uses an actuator 74 to engage second piston 70 and leftward away from piston 70 . Engagement of pawl 68 with the parking gear locks the driven wheels and prevents movement of the vehicle.
[0020] Under normal operating conditions, when line pressure is produced, either by an engine driving a transmission pump or the battery 25 powering e-pump 24 , hydraulic fluid at line pressure passes through latch valve 12 and line 32 to park control valve 14 . Solenoid 18 moves park control valve 14 to a position wherein line pressure is carried in line 38 to the park servo 16 . Line pressure in cylinder 58 of the park servo moves piston 60 leftward. Clockwise pivoting of crank arm 62 against the counterclockwise torque produced by torsion spring 36 causes park pawl 68 to pivot clockwise about axis 69 out of engagement with the parking gear, producing Park-disengagement.
[0021] While Park is disengaged, solenoid 20 and detent 72 hold the park servo 16 in the disengaged position. Under normal operating conditions, solenoid 20 is closed, i.e., in the Park-disengaged position, such that no power is consumed. With solenoid 20 in the closed position, the vehicle can be towed with four wheels contacting the road surface. Line pressure in cylinder 58 applies a secondary force to maintain the park servo 16 in the Park-disengaged position.
[0022] Under normal operating conditions, when solenoid 20 is electrically energized, actuator 74 releases the pistons 60 , 70 allowing rightward movement, pivoting crank arm 62 counterclockwise, displacing park rod 66 rightward, and causing park pawl 68 to pivot counterclockwise into engagement with the parking gear and producing Park-engagement.
[0023] Under normal operating conditions, while the system 10 produces Park-engagement, fluid in cylinder 58 is forced through line 38 to the exhaust port of park control valve 14 , as pistons 70 , 60 move rightward in cylinder 58 .
[0024] If solenoid 20 becomes inoperative, such as due to loss of electric power supply to solenoid 20 or failure of a component of the solenoid, the system returns to Park-engagement as hydraulic pressure, produced by e-pump 24 , pressurizes cylinder 58 through solenoid 22 and line 42 . That pressure is present also in the space 80 between the pistons 60 , 70 due to radial passage 82 . Space 80 is retained by dent balls 84 and spring 72 . Pressure in space 80 detaches piston 60 from piston 70 . Pressure in cylinder 58 is vented though line 38 and the exhaust port EX of park control valve 14 . Spring 36 pivots crank arm 62 clockwise and park pawl clockwise into engagement with the parking gear, thereby engaging Park.
[0025] Solenoid 20 may be electrically energized by a charged capacitor through a FET at 86 .
[0026] In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described. | A vehicle park-brake system includes a park brake, a solenoid; a first pressure source; a servo for disengaging the park-brake using the first pressure source, and for disengaging the park-brake using a force produced by the solenoid that actuates first and second pistons; and a second pressure source applied to the servo causing hydraulic pressure to vent from the servo, the pistons to detach mutually, and the servo to engage the park brake. | 1 |
[0001] This application is a continuation of U.S. patent application Ser. No. 09/897,153, filed Jun. 29, 2001, which claims the benefit of U.S. Provisional Application No. 60/215,257, filed July 3 , 2000 , the entire disclosures of which are hereby incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to chairs and seating normally associated with but not limited to residential or commercial office work. These chairs employ a number of methods of to enhance the user's comfort and promote ergonomically healthy sitting. These methods include various forms of padding and flexing of the seat and back as well as separate mechanical controls that control the overall movement of the seat and back.
BACKGROUND OF THE INVENTION
[0003] Various approaches to making a chair's seat and back form fitting for various users are known in the industries of seating manufacture. These approaches range from the rather traditional use of contouring synthetic foam, to seat/back shells that have a degree of flex. There have also been approaches that use a frame that has a membrane or sling stretched or supported within said frame. Several problems exist with each of these approaches.
[0004] In the case of simply using foam padding, under normal manufacturing conditions it is difficult if not impossible to properly vary the amount of firmness and thus support from one area of a cushion to another. Additionally, having to use foam can lead to excessive heat-build-up between the seating surface and the occupant. One of the problems with foam is the forming/molding of it. Current manufacturing technology makes it a relatively inefficient process compared with the manufacture of the other components that make up a chair of seating surface. The forming/molding of a contoured seating surface is so slow that the manufacturer is forced to make many sets of molds (which usually are hand filled) in order to maintain the production pace. This is contrasted by a part or component that is made for the same piece of furniture yet it can be produced on a single injection-molding machine with a single mold and keep pace. Another problem inherent to the use of foam is that in order to achieve a finished look the cushions must be upholstered. When a manufacturer is forced to upholster a cushion a number of problem issues arise. Usually the formed or molded foam has curves, many of which can be compound-curves, which leads a manufacturer to use glue or other adhesives to make the fabric conform to the contours. This laminating technique often makes the foam's surface firmer than it was when it was originally molded/formed because the glue/adhesive and the fabric are now part of the foam structure. Additionally, the amount of change can vary from fabric to fabric which results in an unpredictability of the firmness of a cushion from one manufactured unit to the next. If a slipcover is used, it must be sized properly. Such sizing can be difficult as a result of the differing mechanical properties found from one fabric to another. The most important properties of a fabric when upholstering a contoured surface are its thickness and its rate of stretch. Thickness variations can make one fabric upholster smooth around radii or contours, while a thicker one will wrinkle in the same area. Variations in the amount of stretch can lead to other problems. And so a proper size slipcover in one type of fabric, with its stretch characteristics, can be the wrong size in another type or style of fabric. Often a manufacturer will “wrap” a piece of fabric around a cushion and then staple the fabric to the underside/backside of the cushion. This approach also suffers from the aforementioned problems associated with using variable fabrics. Additionally, The manufacturer must now cover the staples and the area of the cushion not covered by fabric in order to achieve a finished look. This leads to an additional molding etc. that often also has to be upholstered.
[0005] The other reality of cushion upholstery, regardless of the techniques used, is that whether it is done in a small shop or in a production situation, it is consistently the most labor-intensive aspect of chair/seating construction.
[0006] In the case of incorporating flex into the shells of a chair, no geometry to date has achieved the proper amount of flex in the right areas to give correct ergonomic comfort for a wide range of individuals. In the case of a sling approach, the curves imparted on the sling by the frame are simple in nature (non-compound) and thus cannot provide the proper contouring necessary for ergonomic comfort. Also, this approach leads to “hammocking”. Hammocking is when the sling is pressed in one area; the areas immediately adjacent have the tendency of folding inward, squeezing the occupant, again not yielding the proper ergonomic curvatures. An additional problem with sling chairs is that if the manufacturer makes the supporting sling surface taut enough to properly support a large-heavy person, the tension on the sling will be too great for a smaller person, resulting in discomfort.
[0007] Finally, the present state of the art dictates that the contours a designer may choose in seating design be generic in nature to accommodate the widest range of the population possible. In an effort to increase comfort, manufacturers have produced “sized” (i.e. small, medium and large) chairs that effectively narrow the amount of contouring-compromise that the designer must normally exercise. Unfortunately, this leads to the manufacturer having to tool three independent products instead of one, and the manufacturers, wholesalers, and retailers having to stock (in this example) three times the quantity of product. Additionally, the end user is stuck with a chair that at some point in the future may be the wrong size. This invention addresses these shortcomings with a new and novel approach to seating construction.
SUMMARY OF THE INVENTION
[0008] The present invention relates to an improved method of constructing seating surfaces, which provides greater comfort through superior surface adjustment for a variety of users. The seating surface construction is comprised of a plurality of support sections, or bosses/platforms and of a plurality of web connectors interconnecting the support sections. The support sections, or bosses/platforms are more rigid than their corresponding web connectors. A variety of methods are disclosed for making the bosses/platforms exhibit a greater degree of rigidity than the web connectors. One such method disclosed is to alter the thickness of the bosses/platforms versus the web connectors. And another method is to provide the bosses/platforms with stiffening geometry that provides a greater degree of rigidity than the web connectors. Such stiffening means could be the addition of one or more returns or ribs. Another is to make the bosses/platforms out of a different material than the web connectors. And another is to construct the webs with a geometry that acts as a hinge. Yet another is to make the given geometry out of a material that can exhibit stretch in addition to flexure. The invention also provides greater airflow to contact areas of the occupant's body, because foam is not necessary to create a comfortable seating surface. Additionally, the seating surface is more efficient and economical to produce.
[0009] So, an object of the present invention is to provide a new and improved method of chair seat and back pan construction, which provides greater comfort for the user. A further object of the invention is to provide a new and improved method of chair seat back pan construction, which provides superior surface adjustment for a variety of users. A further object of the invention is to provide a new and improved method of chair seat back pan construction, which provides greater airflow to contact areas of the occupant's body. A further object of the invention is to provide a new and improved method of chair seat back pan construction, which is more efficient and economical to produce.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is top view of the chair showing its support frame with its seat-pan seating surface removed.
[0011] FIG. 2 is a side elevation of the chair according to the present invention.
[0012] FIG. 3 is a front view of the back resilient seating surface.
[0013] FIG. 4 is a front view of the resilient seat-pan seating surface.
[0014] FIG. 5 is a top view of the back seating surface and seat-pan seating surface of figures three and four.
[0015] FIG. 6 is a side view of the back seating surface of figure three.
[0016] FIG. 7 is a top view of the seat-pan frame and the backrest frame that is capable of receiving the seating surfaces of figures three through six.
[0017] FIG. 8 is a front view of the seat-pan frame and the backrest frame that is capable of receiving the seating surfaces of figures three through six.
[0018] FIG. 9 is a side view of the seat-pan frame and the backrest frame, which is capable of receiving the seating surfaces of, figures three through six.
[0019] FIG. 10 is a top view of the seat-pan frame and the backrest frame with the resilient seating surfaces of figures three through six affixed in place.
[0020] FIG. 11 is a front view of the seat-pan frame and the backrest frame with the resilient seating surfaces of figures three through six affixed in place.
[0021] FIG. 12 is a side view of the seat-pan frame and the backrest frame with the resilient seating surfaces of figures three through six affixed in place.
[0022] FIG. 13 is a detail view consisting of a substantially flat web.
[0023] FIG. 14 is a detail view consisting of a configured web that has a V-shaped cross-section.
[0024] FIG. 15 is a plan view of the webbing structure.
[0025] FIG. 16 is a detail anoxemetric view of FIG. 15 , showing one form the web may assume.
[0026] FIG. 17 is a detail anoxemetric view much like FIG. 16 , except a single structural relationship is depicted, showing another form the web may assume.
[0027] FIG. 18 is a detail anoxemetric view much like FIG. 16 , showing several cells linked together.
[0028] FIG. 19 is a detail anoxemetric view much like FIG. 18 , except a larger field of structural relationships is depicted.
[0029] FIG. 20 is a side sectional view taken along cutting line A-A of FIG. 19 .
[0030] FIG. 21 is a side sectional view taken along cutting line B-B of FIG. 19 .
LIST OF REFERENCE NUMERALS USED IN THE FIGURES
[0031]
2 —Seat frame
4 —Back frame
6 —Resilient seat surface insert
8 —Resilient back surface insert
10 —Mounting groove of 2
12 —Mounting groove of 4
14 —Arm support structure
16 —Arm pads
18 —Web connectors of 6 / 8
20 —Thickened support sections, or bosses/platforms of 6 / 8
22 —Openings of 6 / 8
24 —Zone of greatest flexibility
48 —Tension adjustment knob
DETAILED DESCRIPTION OF THE INVENTION
[0044] While the invention will be described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to that embodiment. On the contrary, I intend to cover all alternatives, modifications and equivalents within the spirit and scope of the invention.
[0045] Referring to FIG. 10 a top view of the seat-pan seating surface and its support frame can be seen. And by referring to FIGS. 3-6 , the shells or pans can be seen separate from the frames, and the frames can be seen separate from the seating surface shells or pans in FIGS. 1 , 2 , 7 , 8 , and 9 . Also, it should be noted that a separate peripheral support frame is not a necessity of the invention, for the shells could be self-supporting with an integral structure. Additionally for clarification, a seat-pan, or back-pan seating surface refers to a structure which may be the primary surface, as in a plastic or wood chair, or a structure which may accept foam and upholstery and thus not be the primary surface as can be commonly found in many articles of furniture. Often these structures are also referred to as seating shells. All of these and any other terms used to describe a similar structure are considered to be equivalents and should be viewed as such.
[0046] Now referring to FIGS. 3 and 4 it can be seen that the seating surface is comprised of a plurality of webs 18 , thicker sections, or bosses/platforms 20 , and openings 22 . It is through the various geometric combinations of the three of these basic elements that improved seating comfort is achieved. This is why we also refer to the matrix as being “cellular” in nature, for it is a matrix of individual, independently acting cell structures. One embodiment has all three of these structures formed economically from one type of material and process such as plastic and molding. Any of the common molding methods known could be used including, but not limited to, injection, blow, or roto-molding. Additionally, through the use of advanced plastic injection molding techniques known to those in the industry as “two-shot” injection molding and “co-injection” molding, these elements may be selectively made from two or more types of materials to further control the overall engineering attributes of the structure. Additionally, this structure could be realized through other manufacturing techniques such as lamination, stamping, punching etc.
[0047] Referring to FIG. 16 , a closer view of some of the matrix, it can be seen that the webs 18 , function as thinner or more flexible interconnecting elements to the thicker or more rigid bosses/platform sections 20 . It is through these webs that flexure occurs, allowing movement of one thicker or more rigid section relative another thicker section. Depending upon the final geometry selected this movement may have several degrees of freedom. For example, if the web is of the form as in detail FIG. 16 , where the web is predominantly flat in form, the web may act as a both a torsional flexure (occurring predominantly across the webs width) for the thicker or more rigid bosses/platform sections, as well as a linear flexure along its length. Additionally, depending on the characteristics of the materials used, the web may stretch in length, allowing another form of displacement. If, however, the web is of the form found in detail FIG. 14 , where the web is formed as a V, or an inverted V, the web may exhibit the preceding characteristics as well as act as a living hinge allowing the angle formed by the faces of said V to change. This would result in a different set of degrees of freedom of one boss/platform section relative to another. Both of the aforementioned forms of webs, and other contemplated designs, all may share common types of flexure of varying degrees. It should be noted that the terms “thinner” and “thicker” sections are interchangeable with the terms “sections having greater” or “sections having less” flexibility relative to each other. Cross-sectional area or thickness is but one way of varying the relative rigidity of the webs vs. the bosses or platforms. Another way is to provide the bosses or platforms with rigidizing returns, ribs or walls, so that structurally the bosses or platforms are stiffer than the joining webs. Additionally, as stated earlier, the materials selected could play an important role in the performance of the geometry. For example, if the material selected is an elastomeric material, such as a urethane, the webs 18 could each stretch or elongate a small amount resulting in or allowing deflection or displacement of the thicker or more rigid bosses/platform sections 20 . Another flexible material under consideration is Hytrel® polyester elastomer by Dupont. By each area responding individually the entire seating surface may emulate a soft cushioning effect to the occupant. As also mentioned earlier, it is possible through advanced molding techniques or fabrication, to use more than one type of molded material in a finished product. One such technique is to mold a part in one material in one mold and then place the part into another mold that has additional cavity area, and then fill that mold with another type of material. So it may be advantageous to for example to mold all the webs and connective areas in one material in one mold, and then to transfer the part to another mold to form all the thicker or more rigid bosses/platform sections and other features in another material.
[0048] Because the platforms are joined by webs, holes, or areas lacking material are created which allow airflow and thus reduces the amount of heat build up on the seating surface. These holes, or areas with no material, further serve to allow the desired movement of the webs and the thicker sections. As shown, the holes are octagons, but any shape found suitable could be used. Referring to FIG. 17 , a detail anoxemetric view much like FIG. 16 , except a single structural relationship is depicted, showing another form the web structure may assume. The difference of this form of web structure can be appreciated by referring to FIGS. 19, 20 , and 21 . Rather than the bosses/platforms being thicker in cross-sectional than the web connecting members, the bosses/platforms are provided with structural returns or reinforcing ribs. Thus functionally, the bosses/platforms will have a greater structural rigidity relative to their interconnecting web members. FIG. 20 which is a sectional view taken along cutting line A-A of FIG. 19 and FIG. 21 which is a sectional view taken along cutting line B-B of FIG. 19 , show that the bosses/platforms have reinforcing returns that make the bosses/platforms more rigid than the connecting web structure. As shown the return wall on the bosses/platforms forms a ring. This is not a necessity though, the returns could be as simple as a single rib or as complex or as many returns as are needed.
[0049] A critical aspect of this invention is the ability of the designer/manufacturer to precisely control and alter all aspects of the deflection of the seating surface from area to area simply and controllably. When a designer/manufacturer specifies a foam density (firmness/softness) for a cushion, the entire cushion is compromised by that unifying density. That is not the case with this invention though.
[0050] Biomapping is datum created through the comparison of body contours of a given population, or the datum created through the comparison of contact forces exerted between a seating surface and the occupant. Although exercises in generating data have been ongoing for several years, the designer is still limited to selecting generic contours, and then hopes that the foam would resolve the final fitting issues. This invention, however, makes it possible to effectively use the data generated by biomapping to precisely control the geometry (web-connectors, bosses/platforms, and openings) and thus the engineering properties area by area over the entire seating surface, so that each sector-area is functionally optimized.
[0051] So it should be appreciated that by varying the size and shape of the holes, the location of holes, the types of webs and their relative thickness, or geometry and the size, contour and relative thickness of the thicker sections or their geometry, a designer can custom design each area of a seating surface to perform as desired. FIG. 3 shows how the seating surface could be divided into zones; one such zone is indicated by area 24 . This could be the zone of greatest flexibility. It should also be appreciated the advantage this offers the designer when he is trying to economically manufacture an item from a material such as plastic, as well as the increased comfort that the user will experience.
[0052] Referring to FIGS. 7-9 both the seating frame 2 and the back frame 4 can be seen. It is substantially more rigid than the seating surface. It provides a support structure for the seating surface, and as a means to connect the seating surface to the rest of the chair. In one contemplated embodiment the seating surface is carried within the seating frame by way of mounting grooves 10 and 12 . It should be appreciated that the seating surface and the frame could be formed or manufactured as a single unit; however, several advantages may be realized if they are separate. One such advantage is that they may be made of differing materials. In this way, each of the materials selected for their respective part may be optimized functionally. Another advantage is that the way in which the two members, the seating surface and its frame, are attached may be variable. Techniques of manufacture and assembly could be used which would allow movement relative to one another. This would give yet more degrees of movement and cushioning to the occupant. An example of an attachment means is a rubber mount that may take the form of a series of intermediate mounting pads, which occur between the seating surface and its frame. Similarly, the rubber or resilient material could take the form of a gasket occurring between the seat surface and frame. Another way that such movement could be achieved is to produce a groove integral to the seating surface that would follow the same path as the mounting groove. Such a groove could be pleated like the web found in FIG. 14 , and thus would allow a degree of lateral movement. Another method would be to have the seating surface snap into place using tabs and slots that had enough free-play relative to each other to yield desirable results. Either the seating surface or the frame could have the slots and the other the tab members. Yet another method would be to configure the two elements so that one or the other had standing legs formed predominantly perpendicular to the other element. In this way, when the two are assembled, and allowed to shift relative to each other, the legs flex. This, like the rubber or resilient mounts would allow biased relative movement, which would not feel loose. These tabs or the functionality of them could be combined with the snap tabs, as a matter of fact; any of the methods could be successfully combined. Additionally, any of these attachment techniques could occur using mounting grooves such as 10 and 12 , or could surface mount directly on the surface of the seat/back frames. It is also contemplated that the entire assembly (frames, resilient seating surface inserts, and flex gasketing material) could be manufactured using the advanced multi-material molding techniques (two-shot, co-injection) previously mentioned. This would have the potentially obvious advantages of increased economy, and ease of manufacture, and increased structural integrity.
[0053] Another critical feature of the invention in regard to the way in which the seating surfaces interact with the seating frame concerns sizing. As previously mentioned, it is a handicap to the designer to try to design a chair with the proper contours for the full range of the population. The resulting designs and contours are necessarily compromises, and thus are not optimal for any given individual. As also previously mentioned, in an effort to overcome these limitations, manufacturers have produced “sized” (i.e. small, medium and large) chairs that effectively narrow the amount of contouring-compromise that the designer must normally exercise. The fact of the matter is that there are several aspects to sizing. The first, and most obvious, is the overall sizing of the surfaces as far as width, height etc. As far as comfort is concerned, this is the least important aspect of seating surface design. Appropriately sized seating surfaces can be formulated that satisfy the extremes. What is most important in achieving seating comfort, is the contouring that occurs within whatever sized seating surface is chosen. Unfortunately, this contouring varies greatly from a small individual, to a large one. Additionally, some individuals who seemingly share the same body types prefer differing contours such as stronger/weaker lumbar contours. Although the present invention addresses this need for variable contouring through its innovative flexure structure, further advantages in comfort can be realized if the initial contours of the seating structure are in the proper range for the occupant. Through the present invention's unique method of construction, these goals are all achievable. As previously outlined, the seating surfaces can be attached to the seating frame by a variety of methods. So, the manufacturer can produce one basic chair frame(s) and then into the same set of frames insert many different contoured seating surfaces. Obviously, this has the advantage of eliminating the need of the manufacturer having to tool three independent products instead of one. It also has additional advantages. Because the seating surfaces are so easily attached and detached from their frames, it is conducive to a field-customization scenario. In this way, wholesalers, and retailers could stock frames, and then have a variety of seating surfaces in various contours and colors. This would allow the retailer could customize the product on the spot for the customer. Additionally, the end user is not stuck with a chair that at some point in the future may be the wrong size. The size/color scheme can be updated at any point of the products life by simply obtaining a fresh set of seating surfaces.
[0054] Thus, a new and improved method of chair seat and back pan construction, which provides greater comfort through superior surface adjustment for a variety of users, has been provided. Also provided is a new and improved method of chair seat back pan construction that provides greater airflow to contact areas of the occupant's body. Also provided is a new and improved method of chair seat back pan construction that is more efficient and economical to produce. | A seating structure includes a plurality of boss structures arranged in a pattern and a plurality of web structures joining adjacent boss structures within the pattern. At least some of the web structures are non-planar and at least some adjacent web structures are spaced apart such that they define openings therebetween. In another aspect, the seating structure includes a plurality of boss structures arranged in a pattern and defining a support surface and a plurality of web structures joining adjacent boss structures within the pattern. At least some adjacent web structures are spaced apart and shaped such that they define substantially non-circular openings therebetween when viewed in a direction substantially perpendicular to the support surface. | 0 |
BACKGROUND OF THE INVENTION
The invention is directed to a thyristor and more particularly to a thyristor with a reduced breakover voltage.
When, in a thyristor, the voltage that is applied between the cathode electrode and the anode electrode, and that blocks the thyristor, is increased to the value of what is referred to as the breakover voltage, then a local breakdown occurs of the pn-junction that separates the p-base from the n-base and proceeds about parallel to a principal face of the semiconductor body. In general, the breakdown appears at that edge of this pn-junction that lies in the lateral surface of the thyristor. In order to avoid such a uncontrollable local breakdown that very often leads to the destruction of the thyristor, European Pat. Publication No. EP-A-O 088 967 discloses that the pn-junction between the p-base and the n-base may be provided with a projecting part that reduces the thickness of the n-base, formed, for example, by means of irradiation with a laser beam under the central ignition contact of the thyristor, and to thus produce a breakdown at a reduced breakover voltage, this breakdown appearing in the region of the projecting part. This breakdown leads to an over voltage ignition of the thyristor so that a thermic destruction does not occur as a result of the reduced breakover voltage. What is disadvantageous, however, is that the reduced breakover voltage cannot be set to a defined voltage value with the desired precision and reproducibility.
SUMMARY OF THE INVENTION
The object of the invention is to specify a thyristor of the species initially cited wherein the pn-junction between the p-base and the n-base breaks down in defined fashion, when a reduced breakover voltage that can be set in a simple way is reached, this breakdown occurring without thermal destruction. This is achieved by the present invention.
The advantage obtainable with the invention is especially that a reduced breakover voltage at which the pn-junction between the p-base and the n-base of the thyristor breaks down, without the thyristor suffering damage, can be set with adequate precision and reproducibility.
SUMMARY OF THE DRAWINGS
The invention shall be set forth in greater detail below with reference to the drawings, in which:
FIG. 1 illustrates a first exemplary embodiment of the invention;
FIG. 2 illustrates a second exemplary embodiment; and
FIG. 3 illustrates a preferred method for the manufacture of a thyristor of FIGS. 1 or 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a power thyristor that comprises a doped semiconductor body having four successive semiconductor layers of alternating conductivity types. In detail, these are composed of an n-emitter 1, of a p-base 2, of an n-base 3 and of a p-emitter 4. The n-emitter 1 is contacted by an electrode 5 at the cathode side that is provided with a terminal K; the p-emitter 4 is contacted by an electrode 6 at the anode side that is provided with a terminal A. An external circuit connected at A is composed of a load resistor R and of a voltage source V lying in series therewith, this voltage source V, for example, outputting a d.c. (or a.c.) voltage of 1000 volts between R and a terminal 7 at reference potential. The terminal K is also connected to reference potential. The electrode at the anode side is thereby placed at a potential that is positive in comparison to K, by the voltage supplied by V, so that the thyristor is in what is referred to as its blocked condition.
An ignition contact or gate 8 that contacts the p-base 2 is provided with a terminal 9 to which a positive voltage pulse is supplied by a gate trigger circuit referenced 10 in order to ignite the thyristor. When the ignition switches the thyristor situated in its blocking condition into its current-carrying condition, then it closes the external circuit that proceeds A,R,V,7 and K via a low-impedance connection of K and A. The quenching of the thyristor, i.e. the conversion thereof into the high-impedance, non-current-conducting condition, ensues by switching off the voltage source V or, in case V is an a.c. voltage source, ensues at the first zero-axis crossing of the a.c. voltage supplied by V that appears after the ignition.
An n-conductive region 11 inserted into the p-base is provided with a conductive coating 12 that is extended to such an extent in the direction toward the n-emitter 1 that it shorts the p-n junction between 11 and 2. The parts 11 and 12 then form what is referred to as an auxiliary emitter or amplifying gate that represents an internal ignition amplification of the thyristor. In the case of a dynamically balanced structure of the thyristor, the dot-dash line 13 is the axis of symmetry of the thyristor. Reference numeral 1a references recesses of the n-emitter 1 that are filled out with corresponding projections 2a of the p-base 2. The latter are contacted by the electrode 5 of the cathode side. The parts 1a and 2a form emitter-base shorts that prevent an undesired ignition of the thyristor given the application of blocking voltages.
A p-n junction 14 that is biassed in non-conducting direction, in the case of application of a blocking voltage to the terminals A and K, is situated between the p-base 2 and the n-base 3. When the blocking voltage lying between A and K is raised to the value of what is referred to as the breakover voltage, then the local breakdown of the pn-junction 14 that then arises leads to a uncontrollable ignition of the thyristor that can thermally destroy it.
In order to eliminate this risk, the doping concentration of the p-emitter 4 within a sub-region 15 is inventively dimensioned higher than in the remaining part of the p-emitter 4. The sub-region 15 thereby lies roughly under the ignition or gate contact 8 or, in the case of a concentric or axial symmetric fashioning of the thyristor, lies in the region of the axis of symmetry in order to guarantee an optimally fast ignition propagation. In FIG. 1, the sub-region 15 lies immediately adjacent to the outer boundary surface 4a of the p-emitter 4 that is contacted by the electrode 6 of the anode side, and has a penetration depth that is less than the penetration depth of the p-emitter 4. On the other hand, the penetration depth of the sub-region 15 can, alternatively, correspond to that of the p-emitter 4 or can be even greater. Further, is also possible, alternatively, that the sub-region 15 of the p-emitter 4 is separated from the boundary surface 4a by a sub-layer of the p-emitter 4. This case could be illustrated in FIG. 1 by a vertical displacement of the sub-region 15 drawn with broken lines, in the upward direction. With the arrangement of FIG. 1, when the doping concentration of the p-emitter 4 at the boundary surface 4a to the electrode 6 of the anode side amounts to about 10 18 cm -3 , then a corresponding value of 10 20 cm -3 should be expediently provided for the sub-region 15. The increase of the doping concentration within the sub-region 15 produces an increase in the gain α pnp critical for the layer sequence 2, 3 and 4 in the region of the axis 13 of symmetry, this resulting in a reduction of the breakover voltage to the value of a reduced breakover voltage. The boosting of the doping concentration in the sub-region 15 is accomplished advantageously by way of an ion implantation that is followed by a tempering step. What is to be understood by the latter is a heating of the semiconductor body to about 950°C. through 1200°C. for a time space of, for example, 30 minutes to 30 hours.
The reduced breakover voltage that has been set in the described way can be shifted in the direction of higher values by irradiating the semiconductor body with electrons or protons in the region of the ignition contact 8. This causes the lifespan of the carriers and, thus, the gain α pnp to be lowered in the irradiated region. In FIG. 1, the roughly cylindrical region that has been irradiated in this way is indicated by the broken boundary lines 16.
After the irradiation of the region 16 with electrons or protons has been carried out, the amount by which the reduced breakover voltage has been shifted in the direction toward higher voltages can still be corrected by applying a further tempering step, i.e. can be slightly diminished. In the further tempering step, the semiconductor body is exposed to a temperature of, for example, 250° through 350°C. over a prescribed time span of, for example, 30 minutes through 20 hours, whereby the lifespan of the carriers in the region 16 is again slightly lengthened. This irradiation and the further tempering step then effect an advantageous fine adjustment of the reduced breakover voltage.
FIG. 2 shows a light-triggerable thyristor wherein the electrical ignition with the ignition contact 8 is replaced by a light ignition by irradiating a light-sensitive thyristor zone 17a lying roughly in the region of the axis 13 of symmetry with a light pulse. The light pulse is reference 17 in FIG. 2. A light guide that, in particular, can be fashioned as disclosed in detail in European Pat. Publication No. EP-A-O 197 512 is generally used for supplying the light pulse. Here, too, a reduced breakover voltage is set by the sub-region 15, and this reduced breakover voltage can be shifted in the direction toward higher voltages with an additional irradiation of a region 16 extending from the light-sensitive thyristor zone in vertical direction up to the electrode 6 of the anode side with electrons or protons. The amount of this shift can again be slightly reduced by a tempering step. In the arrangement of FIG. 2, an advantageous effect is achieved that the light sensitivity is increased by the increased gain α pnp without significant disadvantage for the dV/dt behavior.
In the manufacture of a thyristor of the invention, one proceeds on the basis of a n-conductive semiconductor body 18 in the form of a flat wafer that is provided with a p-diffusion zone at the edge side in a known way, this p-diffusion zone extending into the semiconductor body up to the lines 19 and 20 (FIG. 3). After the removal of the wafer edge up to the lateral faces 21 and 22, the upper part of the p-diffusion zone represents the p-base 2, whereas the lower part of the p-diffusion zone forms the p-emitter. After the application of a mask 23 of SiO 2 or of light-sensitive lacquer, a mask window 24 is provided in a photolithographic way, and acceptor ions having an implantation does of, for example, 10 16 cm -2 are introduced through this window in a following implantation step that is referenced 25. The more highly doped sub-region 15 of the p-base 4 then arises in the following tempering step. The irradiation of the region 16 with electrons or protons is undertaken in a particle beam apparatus, whereby a mask 27 provided with a hole 26 prevents the irradiation of the thyristor parts lying outside of 16. It is of particular advantage that this irradiation can also be undertaken at the finished thyristor that, for example, is already provided with the coatings or, respectively, electrodes 8, 12, 5 and 6. The mask 27 can also be composed of a dotting contact that is put in place on the electrode 5 during operation for better conductance of the load current. The correction of the shift of the breakover voltage undertaken by irradiation with electrons or protons can also ensue at the finished thyristor on the basis of the said further tempering step.
Optionally, the parts 11 and 12, serving the purpose of internal ignition amplification, can be eliminated in a thyristor of the invention.
It will be apparent that various modifications and/or additions may be made in the apparatus of the invention without departing from the essential feature of novelty involved, which are intended to be defined and secured by the appended claims. | A thyristor with an npnp layer sequence in which the p-emitter (4) comprises a sub-region (15) in the lateral region of an ignition contact (8) or of a light-sensitive zone (17a), this sub-region (15) being provided with a higher doping concentration that the remaining part of the p-emitter (4). A controllable over voltage ignition of the thyristor occurs at an adjustable, reduced breakover voltage, such breakover voltage being established by selectively irradiating a zone of the thyristor to reduce the breakover voltage point. | 7 |
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates generally to material handling systems and, more particularly, to an improved discharge chute for use with tilt tray sorter material handling systems.
(2) Description of the Prior Art
Conventional tilt tray sorters discharge their goods onto individual chutes located near each packer. The upper surfaces of the chutes are formed from stainless steel or corrosion resistant aluminum, polyethylene, wood, plastic, fiberglass, or other similar, low friction material in order to stand up against the constant wear and tear of day in and day out usage. One example of such a chute is shown in U.S. Pat. No. 5,220,986 issued Jun. 22, 1993 to Fortenbery.
However, the cost of a sorter is about $1500 per linear foot. Accordingly, it is well known to discharge on both sides of the sorter to double its capacity. It is also known to use a two-position chute which can unload articles to two separate cells at one chute location therefore also doubling the sorter's granularity. Granularity is defined as the number of distribution points or cells per conveyor length. However, because of the high cost per foot of the sorter there still remains a need for even further increases in discharge granularity.
Thus, there remains a need for a new and improved chute for material handling applications which further increases discharge density at least 150% while, at the same time, is economical to manufacture and maintain.
SUMMARY OF THE INVENTION
The present invention is directed to a multi-cell discharge chute for a material handling system including a plurality of tilt trays. The chute includes at least three cells arranged generally perpendicular to the travel of the material handling system and aligned with respect to one another and a plurality of guide pans associated with each of the cells. A diverter door is located between the material handling system and the inlets of each of the plurality of guide pans. The diverter door is movable between each of the inlets by a multi-position actuator whereby the multi-cell discharge chute is operable to selectively discharge articles from the material handling system into each of the cells. In the preferred embodiment the multi-position actuator is a tandem pneumatic cylinder having air cushions at each end stop to reduce noise created by operation of the cylinder when it reaches the end of its stroke.
In the preferred embodiment, the chute includes a discharge control system for preventing the material handling system from discharging an article into more than one of the aligned cells within a predetermined delay time thereby preventing the material handling system from discharging an article into a cell before the discharge chute is positioned with respect to the cell.
Accordingly, one aspect of the present invention is to provide a multi-cell discharge chute for a material handling system including a plurality of tilt trays. The chute includes: (a) a plurality of cells arranged generally perpendicular to the travel of the material handling system and aligned with respect to one another; (b) a plurality of guide pans associated with each of the cells; and (c) a diverter door located between the material handling system and the inlets of each of the plurality of guide pans, the diverter door being movable between each of the inlets whereby the multi-cell discharge chute is operable to selectively discharge articles from the material handling system into each of the plurality of cells.
Another aspect of the present invention is to provide a multi-cell discharge chute for a material handling system including a plurality of tilt trays. The chute includes: (a) at least three cells arranged generally perpendicular to the travel of the material handling system and aligned with respect to one another; (b) a plurality of guide pans associated with each of the cells; and (c) a diverter door located between the material handling system and the inlets of each of the plurality of guide pans, the diverter door being movable between each of the inlets whereby the multi-cell discharge chute is operable to selectively discharge articles from the material handling system into each of the cells.
Still another aspect of the present invention is to provide a multi-cell discharge chute for a material handling system including a plurality of tilt trays. The chute includes: (a) at least three cells arranged generally perpendicular to the travel of the material handling system and aligned with respect to one another; (b) a plurality of guide pans associated with each of the cells; (c) a diverter door located between the material handling system and the inlets of each of the plurality of guide pans, the diverter door being movable between each of the inlets whereby the multi-cell discharge chute is operable to selectively discharge articles from the material handling system into each of the cells; and (d) a discharge control system for preventing the material handling system from discharging an article into more than one of the aligned cells within a predetermined delay time thereby preventing the material handling system from discharging an article into a cell before the discharge chute is positioned with respect to the cell.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a multi-cell vertical chute constructed according to the present invention;
FIG. 2 is a cross-sectional view of the chute taken along the line 2--2 shown in FIG. 1;
FIG. 3 is a cross-sectional view of a 4 cell horizontal chute constructed according to the present invention; and
FIG. 4 is a flowchart diagram illustrating the discharge control system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like are words of convenience and are not to be construed as limiting terms.
Referring now to the drawings in general and FIG. 1 in particular, it will be understood that the illustrations are for the purpose of describing a preferred embodiment of the invention and are not intended to limit the invention thereto. As best seen in FIG. 1, a multi-cell chute, generally designated 10, is shown constructed according to the present invention for transporting and sorting articles carried by a sorter conveyor 11.
The multi-cell chute 10 includes a diverter door 20 variably positionable between at least three positions to direct the article into guide pans 13, 14, 15 which further direct the articles away from the conveyor. Cells A, B, and C located downstream capture the articles and may hold the articles until they are discharged into hoppers 13', 14', and 15'. A control system 45 tracks the movement of the articles throughout the sorter conveyor and the position of the elements of the multi-cell chutes 10.
The sorter conveyor 11 includes individual conveyor carts 18 that carry articles to the multi-cell chutes along the conveyor track 9. The conveyor carts 18 are actuated and tilted at the various multi-cell chute locations along the conveyor track thereby delivering the articles to the multi-cell chutes. The details of the conveyor carts 18 are included in U.S. patent application Ser. No. 08/632,012, herein incorporated by reference in its entirety. This type of conveyor system is often utilized in a distribution warehouse for preparing outgoing orders to customers. The system provides for a single conveyor system to simultaneously process numerous separate orders.
A platform 19 is positioned between the sorter conveyor 11 and the diverter door 20. Preferably, the front edge 21 of the platform is positioned under the sorter conveyor 11 to capture items being tilted from the conveyor carts 18 preventing them from missing the multi-cell chute. The platform is angled away from the sorter conveyor to continue the movement of the articles and prevent them from becoming stuck on the platform. Preferably, the platform back edge 23 is adjacent to the diverter door 20 to provide a smooth transition.
The diverter door 20 is located between the platform 19 and the guide pans 13, 14, 15. The diverter door 20 is preferably enclosed having a bottom section with opposing sides and a cover such that articles that are placed into the diverter door 20 do not tumble off the chute into another guide pan resulting in a mis-sorted item or onto the floor below the chute.
The edge 34 of the diverter door closest to the platform 19 is pivotally attached to an upper edge of the multi-cell chute to allow the diverter door to swing along an arc between the cells and to feed articles into the guide pans. By way of example, the diverter door illustrated in FIG. 2 is positioned to feed articles into guide pan 14 and cell B. It will be understood by one skilled in the art that the diverter door 20 may feed to any number of cells and may have any number of shapes and designs.
A multi-position actuator 32 mounted between the bottom of the diverter door and the edge of the multi-cell chute controls the position of the diverter door 20. The actuator 32 is able to position the diverter door 20 at an angle of between about 0 to 90 degrees relative to the sorter conveyor 11. In one embodiment, the actuator is a tandem pneumatic cylinder Model # NCGBA32-UIA97015 manufactured by SMC Pneumatics, Inc. that is capable of placing the diverter door at three predetermined positions. In a preferred embodiment, the actuator includes adjustable air cushions at each end stop to eliminate or reduce noise at the end of the stroke.
The guide pans 13, 14, 15 are located downstream of the diverter door to further guide the article as it moves from the sorter conveyor. The guide pans are enclosed to prevent the articles from escaping as they pass along the length of the guide pan. In a preferred embodiment, the edge 30 of the outermost guide pan and cell is transparent to allow for viewing into the interior.
The cell regions A, B, C are located downstream of the guide pans and defined as the area between the guide pans and the hoppers 13', 14', 15'. The cell regions provide for transitioning the articles and further guiding and directing the articles as they move from the sorter conveyor. The cells may have a variety of orientations from substantially horizontal as illustrated in FIG. 3 to substantially vertical as illustrated in FIG. 2. Velocity placed upon the articles upon discharge from the carts 18 and the gravitational force as the articles vertically descend through the chute is sufficient to ensure the article reaches the downstream end of the feeder and does not become stuck within the chute.
Doors 12 are positioned on the ends of the cells as illustrated in FIG. 2. These doors function similar to bombays on airplanes having two opposing complementary doors that each extend across one half of the opening. The doors 12 act as an accumulator to store the articles within the cell until they move downstream into the hoppers. Keeping the doors closed until this time allows the hoppers to be moved in and out of the downstream position without requiring the control system to stop sending articles to the cell. Preferably, the control system 45 controls the functioning of the doors 12. The control system tracks the articles in each cell and the proper timing to open the doors to ensure an accurate order is processed with the correct number and type of articles. In one preferred embodiment, a sensor relays the position of the doors to the control system. The control system 45 further controls the timing of opening and closing the doors from throughout the system to prevent problems such as too many doors opening at one particular moment.
The hoppers 13', 14', 15' are positioned downstream of the doors 12 to catch the articles. It will be understood that the term hoppers may also include boxes, totes, containers, etc. For particular orders, the articles are coupled meaning they are shipped directly to customers without further sorting or packaging. Decoupled orders require the hoppers to be moved away from the multi-cell chutes and packaged at a remote location before distribution to the customer. Alternatively, as illustrated in FIG. 3, stops 28 may be positioned at the end of the guide pans and cells to stop the motion of the articles. In this arrangement, the articles can be removed from the cells and organized in the specific customer orders.
A discharge control system 45 monitors the entire sorter conveyor and multi-cell chute system. The control system includes a reading device to determine the articles placed upon the individuals conveyor carts 18, a means to calculate the position of the cart 18 along the conveyor track 9, and a means to calculate the position of the diverter door 20.
As the sorter conveyor moves articles about the system, the discharge control system determines whether an individual article can be discharged at a given multi-cell chute 10 and be eventually deposited in the correct tote. By way of example as shown in FIG. 2, an article discharged into the multi-cell chute to be deposited in tote 15' will not be deposited correctly as the diverter door 20 is in position to guide articles into tote 14'. The discharge control system monitors the variables involved in the moving system to ensure the accuracy of the system.
A first variable monitored by the discharge control system is the position of the diverter door 20 and the amount of time necessary for the door to be positioned into the proper orientation for the discharged article to reach the correct tote. As shown in FIG. 4, a delay table 50 contains the amount of time necessary for each diverter door in the entire system to be reoriented to the various positions. The time for the door to move positions may be dependant upon such factors as the length of the door, the weight of the door, and speed of the multi-position actuator controlling the door. The discharge control system 45 must further track whether any articles are within the length of the diverter door 20. The system 45 must wait until the articles have passed through the length of the door prior to moving the position to ensure these contained articles are delivered to the correct guide pans. This information is contained within the delay table 50 which is accessed by the control system 45.
An electronic eye 60 is positioned at a fixed position along the sorter conveyor 11 to input into the control system 45 the article placed upon the conveyor cart and the position of the cart relative to the system. Once the control system registers the position of the cart at a moment in time, it can then calculate the articles position at any later time by taking the position in combination with the speed of the sorter conveyor and the time since the fixed position was registered.
By way of example, a cart located at a fixed position at time 0 moving at 20 feet/second, is at a position 100 feet downstream 5 seconds later. The control system 45 contains the positions of every multi-cell chute along the length of the sorter conveyor and can calculate the time for any particular conveyor cart to reach any particular chute. In one preferred embodiment, the conveyor carts form a continuous loop around the conveyor system. By calculating the length of each cart, determining the position of each cart relative to the other carts, and counting a pulse after each cart passes the fixed position, the control system can determine the position of every cart on the conveyor system. By way of example, each cart is four feet in length and cart zero is at the fixed position at time zero. After three impulses have been recorded by the control system indicating that three carts have passed the fixed position, the control system can determine that cart zero is twelve feet downstream of the fixed position, cart one is eight feet downstream, etc. This method allows for the control system to determine the relative position of each cart on the conveyor system.
The control system 45 also contains a listing of the orders to be processed by the system and the location of the orders along the sorter conveyor. This information may be available in a tray look-up table that contains a tray number, a cell number sorting for the article, and the time before the conveyor cart reaches the cell. The control system monitors this information to ensure the articles are placed in the correct multi-cell chutes at the correct times for the orders to be accurately and timely filled. The control system registers an article placed upon a conveyor cart and determines which chute or chutes the article is needed to fill an order. The control system determines the first multi-cell chute that the cart will reach and whether the article can be discharged into the correct tote.
When the control system determines the conveyor cart can be discharged and the diverter door is in the proper position to guide the article to the proper tote, the system will actuate the cart and discharge the article. If the system determines that the article cannot be discharged at the closest needed chute because the diverter door is not in the correct orientation or the conveyor cart cannot be actuated in time to discharge the article into the multi-cell chute, the control system will determine the next multi-cell chute located downstream that requires the article and will discharge it at that chute. The system will continue the process of determining the next available multi-cell chute until each order is complete.
Certain modifications and improvements will occur to those skilled in the art upon a reading of the foregoing description. By way of example, the control system can use distance to track the position of the conveyor carts instead of a being a function of time. Additionally, the diverter doors can be more efficiently designed allowing them to swing faster thereby improving the speed of the conveyor system. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims. | A multi-cell discharge chute for a material handling system including a plurality of tilt trays. The chute includes at least three cells arranged generally perpendicular to the travel of the material handling system and aligned with respect to one another and a plurality of guide pans associated with each of the cells. A diverter door located between the material handling system and the inlets of each of the plurality of guide pans. The diverter door is movable between each of the inlets by a multi-position actuator whereby the multi-cell discharge chute is operable to selectively discharge articles from the material handling system into each of the cells. In the preferred embodiment the chute includes a discharge control system for preventing the material handling system for discharging an article into more than one of the aligned cells within a predetermined delay time thereby preventing the material handling system from discharging an article into a cell before the discharge chute is positioned with respect to the cell. | 1 |
BACKGROUND
[0001] Speech recognition has been the subject of a significant amount of research and commercial development. For example, speech recognition systems have been incorporated into mobile telephones, desktop computers, automobiles, and the like in order to provide a particular response to speech input provided by a user. For instance, in a mobile telephone equipped with speech recognition technology, a user can speak a name of a contact listed in the mobile telephone and the mobile telephone can initiate a call to the contact. Furthermore, many companies are currently using speech recognition technology to aid customers in connection with identifying employees of a company, identifying problems with a product or service, etc.
[0002] Research in automatic speech recognition (ASR) has explored layered architectures to perform speech recognition, motivated partly by the desire to capitalize on some analogous properties in the human speech generation and perception systems. In these studies, learning of model parameters has been one of the most prominent and difficult problems. In parallel with the development in ASR research, recent progresses made in learning methods from neural network research has ignited interest in exploration of deep-structured models. One particular advance is the development of effective learning techniques for deep belief networks (DBNs), which are densely connected, directed belief networks with many hidden layers. In general, DBNs can be considered as a highly complex nonlinear feature extractor with a plurality of layers of hidden units and at least one layer of visible units, where each layer of hidden units learns to represent features that capture higher order correlations in original input data.
[0003] While DBNs have been shown to be powerful in connection with performing recognition/classification tasks, training DBNs has proven to be somewhat difficult. In particular, conventional techniques for training DBNs involve the utilization of a stochastic gradient descent learning algorithm. While this learning algorithm has been shown to be powerful in connection with fine-tuning weights assigned to a DBN, such learning algorithm is extremely difficult to parallelize across machines, causing learning to be somewhat tedious.
SUMMARY
[0004] The following is a brief summary of subject matter that is described in greater detail herein. This summary is not intended to be limiting as to the scope of the claims.
[0005] Described herein are various technologies pertaining to automatic classification. With more specificity, described herein are various technologies pertaining to automatic speech recognition (ASR) and automatic character recognition. With still more specificity, described herein are various technologies pertaining to training a deep convex network through utilization of convex optimization.
[0006] A deep convex network includes a plurality of layered modules, wherein each module includes a specialized neural network that includes a single hidden layer. More particularly, a lowest module in the deep convex network comprises a first linear layer that includes a plurality of linear input units, a non-linear layer that comprises a plurality of non-linear hidden units, and a second linear layer that includes a plurality of linear output units produced by feeding raw training data into the module. For instance, if the deep convex network is utilized in connection with analyzing an image, the plurality of input units can correspond to a number of pixels (or the extracted features) in the image, and can be assigned values based at least in part upon intensity values, RGB values, or the like corresponding to the respective pixels. In another example, if the deep convex network is utilized in connection with ASR, the plurality of input units may correspond to samples of an audio file, wherein values assigned to the input units are based upon characteristics of the respective samples, or correspond to the extracted features from speech waveforms, such as power spectra or cepstral coefficients.
[0007] The hidden layer of the lowest module comprises a plurality of non-linear units that are mapped to the input units by way of a first weight matrix. For instance, the weight matrix may comprise a plurality of randomly generated values between 0 and 1. The non-linear units may be sigmoidal units that are configured to perform non-linear operations on weighted outputs from the input units (weighted in accordance with the first weight matrix).
[0008] The second linear layer includes the plurality of output units that are representative of targets of the classification task. For instance, if the deep convex network is configured to perform digit recognition in either a form of an image or a form of speech (e.g., the digits 1-10), then the plurality of output units may be representative of the values 1, 2, 3, and so forth up to 10. Similarly, if the deep convex network is configured to perform phone recognition, or more generally, large vocabulary speech recognition, then the plurality of output units may be representative of mono-phones, context-dependent phones or phone states. The plurality of non-linear units may be mapped to the plurality of output units by way of a second weight matrix. This second weight matrix can be learned by way of a batch-based learning process, such that learning can be undertaken in parallel. In particular, convex optimization can be employed in connection with learning the second weight matrix. As an example, the second weight matrix can be learned based at least in part upon the first weight matrix, the target values of the classification, and values of the input units.
[0009] As indicated above, the deep convex network includes a plurality of layered modules, wherein each module includes the aforementioned three layers (a first linear layer that includes a plurality of linear input units, a hidden layer that comprises a plurality of non-linear units, and a second linear layer that comprises a plurality of linear output units). The modules are referred to herein as being layered, as output units of a lower module are a subset of the input units of an adjacent higher module in the deep convex network. More specifically, in a second module that is directly above the lowest module in the deep convex network, the input units can include the output units of the lowest module. The input units can additionally include the input units that correspond to the raw training data—in other words, the output units of the lowest module can be appended to the input units in the second module, such that the input units of the second module also include the output units of the lowest module.
[0010] The input units in the second module corresponding to the raw training data can be mapped to the plurality of hidden units by the first weight matrix as described above. The input units in the second module that are the output units of the lowest module can be mapped to the plurality of hidden units by a third weight matrix, wherein such weights can be learned in a pre-training phase. Thereafter, the aforementioned second weight matrix (that describes weights of connections between the hidden units and the linear output units of the second module) can be again learned by way of convex optimization. This pattern of including output units in a lower module as a portion of the input units in an adjacently higher module in the deep convex network and thereafter learning a weight matrix that describes connection weights between hidden units and linear output units via convex optimization can continue for many modules (e.g., tens to hundreds of modules). A resultant learned deep convex network may then be deployed in connection with an automatic classification/identification task.
[0011] Other aspects will be appreciated upon reading and understanding the attached figures and description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 illustrates an exemplary deep convex network that comprises a plurality of layered modules.
[0013] FIG. 2 illustrates an exemplary lowest module in a deep convex network.
[0014] FIG. 3 illustrates an exemplary Nth module in a deep convex network.
[0015] FIG. 4 is a functional block diagram of an exemplary system that facilitates learning weight matrices in a deep convex network through parallel computation.
[0016] FIG. 5 is a flow diagram that illustrates an exemplary methodology for training a deep convex network in a batch-based manner.
[0017] FIG. 6 is a flow diagram that illustrates an exemplary methodology for learning matrix weights in a deep convex network by way of convex optimization.
[0018] FIG. 7 is an exemplary computing system.
DETAILED DESCRIPTION
[0019] Various technologies pertaining to deep convex networks (DCNs) will now be described with reference to the drawings, where like reference numerals represent like elements throughout. In addition, several functional block diagrams of example systems are illustrated and described herein for purposes of explanation; however, it is to be understood that functionality that is described as being carried out by certain system components may be performed by multiple components. Similarly, for instance, a component may be configured to perform functionality that is described as being carried out by multiple components, and some steps in methodologies described herein may be omitted, re-ordered, or combined.
[0020] With reference to FIG. 1 , an exemplary DCN 100 is illustrated, wherein the DCN (subsequent to being subjected to training) can be utilized in connection with performing automatic classification/recognition. Pursuant to an example, the DCN 100 can be employed to perform automatic speech recognition (ASR). In another example, the DCN 100 can be employed to perform character recognition (handwriting recognition). In still yet another example, the DCN 100 can be employed to perform facial recognition. In another example, the DCN 100 can be employed to perform classification of text into one or more topics. Other applications for utilization of the DCN 100 will be readily understood by one skilled in the art of automatic classification/recognition.
[0021] The DCN 100 comprises a plurality of layered modules 102 - 104 , wherein a number of layered modules in the DCN 100 can vary depending upon application, available computing resources (e.g., processing and memory resources) in a computing apparatus that is utilized to train the DCN 100 and/or utilize the DCN 100 for automatic classification/recognition. For instance, the number of modules may be in the tens, or hundreds, or thousands.
[0022] Each of the modules 102 - 104 can be a neural network with a single hidden layer, wherein a weight matrix in the module, as will be described in greater detail below, can be learned by way of convex optimization. This facilitates training the DCN 100 in a batch-based manner, such that training of the DCN 100 (learning weight matrices for the modules 102 - 104 ) can be parallelized across multiple computing devices.
[0023] Additionally, each of the modules 102 - 104 can include a set of linear layers that surround the single hidden layer. The linear layers can include a plurality of input units and a plurality of output units, respectively. The hidden layer comprises a plurality of non-linear units. The input units are mapped to the hidden units with weights defined in one or more weight matrices, and the hidden units are mapped to the output units with weights defined by the desirably learned weight matrix. Learning of the weight matrix that defines weights of connections between the hidden units and output units of a module in the DCN 100 will be described in greater detail below.
[0024] With more detail, the first module 102 (the lowest module in the DCN 100 ) comprises a bottom linear layer 108 that includes a plurality of linear input units, a hidden layer 110 that comprises a plurality of non-linear units, and a top linear layer 112 that comprises a plurality of linear output units. The plurality of linear input units in the first linear layer 108 can correspond to parameters of raw data. For instance, if the DCN 100 is configured to analyze a digital image to recognize characters therein, the raw data may include approximately 800 pixels. Each of the linear input units in the linear layer 108 may correspond to a single pixel in the image, such that the linear layer 108 comprises 800 linear input units. Values of such input units may be intensity values corresponding to the pixels, gradients corresponding to the pixels, or the like. In another example, if the DCN 100 is configured to analyze an audio signal to recognize one or more phones, the raw data may be the audio signal that is sampled into a plurality of separate samples. Accordingly, the number of linear input units in the bottom linear layer 108 may correspond to the number of samples, and values of such input may correspond to certain features of the samples.
[0025] The linear input units of the bottom linear layer 108 can be fully connected to the non-linear units in the hidden layer 110 of the first module 102 , where a weight matrix W RAN represents weights assigned to connections between the linear input units and the non-linear units. With respect to the first module 102 , such weight matrix W RAN can be generated through utilization of a random number generator, wherein values of W RAN are randomly distributed between 0 and 1, e.g., with uniform distribution or Gaussian distribution. Other mechanisms for assigning weights between the input units corresponding to raw training data and non-linear units are contemplated and are intended to fall under the scope of the hereto-appended claims.
[0026] The hidden layer 110 , as mentioned, comprises the plurality of non-linear units that are configured to perform a non-linear mathematical computation on the weighted values corresponding to the input units. Pursuant to an example, the non-linear units can be sigmoidal units, which can be of the form σ(x)=1/(1+exp(−x)), where x is the weighted summation of input units.
[0027] The plurality of output units in the top linear layer 112 can be representative of targets for learning. For instance, if the DCN 100 is configured to perform recognition of digits (e.g., 1-10), then the output units in the top linear layer 112 can be representative of the digits 1, 2, 3, and so forth up to 10 (e.g., there are ten output units). In another example, if the DCN 100 is configured to perform recognition of phones, then the output units in the top linear layer 112 can be representative of possible phones.
[0028] The plurality of non-linear units in the hidden layer 110 can be fully connected to the plurality of output units in the top linear layer 112 , wherein weights of the connections are defined by another weight matrix U, wherein U is desirably learned. For the first module 102 , U can be learned based at least in part W RAN . More particularly, convex optimization can be utilized in connection with learning U. For instance, a pseudo-inverse operation can be employed to learn U, wherein U=pinv(H)T, where pinv is the pseudo-inverse operation, T represents all the targets in the training set for learning (the supervised output values), H=σ(ΣW RAN X), where X represents all the input values in the training set, and the sigmoid function σ described above is applied element-wise. Values assigned to the output units in the top linear layer 112 can be based at least in part upon the weight matrix U.
[0029] As mentioned above, the DCN 100 comprises numerous layered modules—in other words, the output units of the first module 102 are included in a bottom linear layer 114 of the second module 104 as input units. The second module 104 also comprises a hidden layer 116 and a top linear layer 118 , which include substantially similar (identical) units as the first module 102 . Input units in the bottom linear layer 114 of the second module 102 also include the same input units that correspond to the raw training data that were included in the bottom linear layer 108 of the first module 102 . Accordingly, the output units in the top linear layer 112 of the first module 102 are appended to the input units corresponding to the raw data to form the bottom linear layer 114 of the second module 104 , and both sets of units can be referred to collectively as input units of the second module 104 .
[0030] The second module 104 further comprises a single hidden layer 116 that includes a plurality of non-linear units that are fully connected to the input units of the bottom layer 114 of the second module 104 . Weights of connections between input units in the bottom linear layer 114 and non-linear units in the hidden layer 116 can be defined be a set of weight matrices: W RAN and W RBM , where RBM denotes Restricted Boltzmann Machine. W RAN can serve as the weights of connections between the input units that correspond to the raw data and the plurality of non-linear units in the hidden layer 116 , and W RBM are the weights associated with an RBM and can serve as the weights of connections between the input units received from the first module 102 (the output units of the first module 102 ) and the plurality of non-linear units in the hidden layer 116 . Learning of W RBM is described below.
[0031] Again, it is desirable to learn the weight matrix U that defines weights of connections between the plurality of non-linear units in the hidden layer 116 of the second module 104 and the plurality of output units in the top linear layer 118 . In the case of a non-lowest module in the DCN 100 (any module other than the first module 102 ), U can be computed based at least in part upon W RAN and W RBM . Pursuant to an example, U can be computed as follows: U=pinv(H)t, where H=σ(ΣWX), where T and X have been described above (here X is all input units in the bottom linear layer 114 of the second module), W is the concatenation of W RAN and W RBM , and σ(ΣWX)=1/(1+exp(−ΣWX)) applied element-wise. Values for output units in the top linear layer 118 in the second module 104 can then be computed based at least in part upon the learned U for the second module. These output units may then be included as input units in a bottom linear layer of yet another module. Thus, numerous modules can be layered in this fashion, and U can be learned for each layered module.
[0032] Referring briefly to FIG. 2 , a system 200 that facilitates learning U for the first module 102 is illustrated. As described above, the first module 104 comprises the bottom linear layer 108 , the hidden layer 110 , and the top linear layer 112 . The bottom linear layer comprises input units 202 , which correspond to raw training data as described above. The hidden layer comprises a plurality of non-linear units 204 , which may be sigmoidal units. The input units 202 are fully connected to the non-linear units 204 . Weights assigned to connections between the input units 202 and the non-linear units 204 are defined by W RAN . Pursuant to an example, a random number generator 208 can be configured to generate W RAN , wherein values of W RAN can be randomly distributed over a pre-defined range, such as zero to one. The non-linear units 204 perform non-linear computations on values of the input units 202 weighted by the weights in W RAN 206 . W RAN may be replaced here partially or fully by W RBM .
[0033] The top linear layer 112 of the first module 102 comprises a plurality of output units 210 that are fully connected to the non-linear units 204 in the hidden layer 110 . As discussed above, it is desirable to learn a weight matrix U 212 for connections between the non-linear units 204 and the output units 210 . A learning component 214 can receive W RAN 206 from the random number generator 208 (or from a data store), can receive output computations from the non-linear units 204 h , the values of the input units 202 ×(the raw training data), identities of the targets for learning t (identities of the output units 210 ), and can compute U 212 based at least in part thereon through utilization of a convex optimization algorithm. An exemplary convex optimization algorithm has been described above. Values may then be assigned to the output units 210 based at least in part upon the weight matrix U 212 . Additionally, while the learning component 214 has been shown as receiving certain data directly from the first module 104 , it is to be understood that W RAN 206 , x, and t can be known a priori, and the learning component 214 can retrieve such data when needed (immediately subsequent to h being computed by the non-linear units 204 ).
[0034] Referring now to FIG. 3 , an exemplary system 300 that facilitates learning U for the second module 104 is illustrated. While the second module 104 is illustrated in the system 300 , it is to be understood that the system 300 can be utilized to learn U for any module in the DCN 100 that is not the lowest module (e.g., the first module 102 ). The system 300 comprises the second module 104 , which includes the bottom linear layer 114 , the hidden layer 116 , and the top linear layer 118 . The bottom linear layer 114 comprises two sets of input nodes: the input units 202 that were also the input units to the first module 102 , and a second set of input units 302 that are the output units 210 from the first module 102 .
[0035] The hidden layer 116 of the second module 104 comprises a plurality of non-linear units 304 , which may be substantially similar (e.g., identical) to the non-linear units 204 in the hidden layer 110 of the first module 102 . The first set of input units 202 in the bottom linear layer 114 is fully connected to the non-linear units 304 in the hidden layer 116 , wherein weights of connections are defined by W RAN 206 . Additionally, the second set of input units 302 in the bottom linear layer 114 is also fully connected to the non-linear units 304 in the hidden layer 116 , wherein weights of connections are defined by W RBM 305 , which can be pre-computed in a pretraining phase. Computation of W RBM 305 for the second set of input units 302 will now be described.
[0036] A pair of layers in a module of the DCN 100 can be treated as a Restricted Boltzmann Machine (RBM). With more detail, an RBM is a particular type of Markov random field (MRF) that has one layer of (typically Bernoulli) stochastic hidden units and one layer of (typically Bernoulli or Gaussian) stochastic visible units. RBMs can be represented as bipartite graphs since all visible units are connected to all hidden units, but there are no visible-visible or hidden-hidden connections.
[0037] In the RBMs, the joint distribution p (v, q; θ) over the visible units v and hidden units q, given the model parameters θ, can be defined in terms of an energy function E (v, q; θ) of the following algorithm:
[0000]
p
(
v
,
q
;
θ
)
=
exp
(
-
E
(
v
,
q
;
θ
)
)
Z
,
(
1
)
[0000] where Z=Σ v Σ q exp(−E(v, q; θ)) is a normalization factor or partition function, and the marginal probability that the model assigns to a visible vector v can be defined as follows:
[0000]
p
(
v
;
θ
)
=
∑
q
exp
(
-
E
(
v
,
q
;
θ
)
)
Z
(
2
)
[0038] For a Bernoulli (visible)-Bernoulli (hidden) RBM, the energy is as follows:
[0000] E ( v,q ;θ)=−Σ i=1 V Σ j=1 Q w ij v i q j −Σ i=1 V b i v i −Σ j=1 Q a j q j , (3)
[0000] where w ij represents the symmetric interaction term between visible unit v i and hidden unit q j , b i and a j represent the bias terms, and V and Q are the numbers of visible and hidden units. The conditional probabilities can be calculated as follows:
[0000] p ( q j =1 |v ;θ)=σ(Σ i=1 V w ij v i +a j ) (4)
[0000] p ( v i =1 |a ;θ)=σ(Σ j=1 Q w ij h j +b i ), (5)
[0000] where σ(x)=1/(1+exp(−x)).
[0039] Similarly, for a Gaussian-Bernoulli RBM, the energy is as follows after assuming that the variance is unity:
[0000] E ( v,q ;θ)=−Σ i=1 V Σ j=1 Q w ij v i q j +½Σ i=1 V ( v i −b i ) 2 −Σ j=1 Q a j q j , (6)
[0000] The corresponding conditional probabilities become:
[0000] p ( q j =1 |v ;θ)=σ(Σ i=1 V w ij v i +a j ) (7)
[0000] p ( v i |q ;θ)= N (Σ j=1 Q w ij q j +b i ,1) (8)
[0000] where v i can take real values and can follow a Gaussian distribution with mean Σ j=1 Q w ij q j +b i and variance of one. Gaussian-Bernoulli RBMs can be used to convert real-valued stochastic variables to binary stochastic variables which can then be further processed using the Bernoulli-Bernoulli RBMs.
[0040] Following the gradient of the log likelihood log p (v;θ) the update rule for the weights can be obtained as follows:
[0000] Δ w ij = v i q j data − v i q j model , (9)
[0000] where v i q j data is the expectation observed in the training data and v i q j model is that same expectation under a defined distribution for the DCN 100 . Unfortunately, v i q j model can be extremely expensive to compute exactly so the contrastive divergence (CD) approximation to the gradient may be used where v i q j model is replaced by running a Gibbs sampler initialized at the data for one full step.
[0041] From a decoding point of view, the DCN 100 can be treated as a multi-layer perceptron with many layers. The input signal (from the training data) can be processed layer by layer through utilization of equation (4) until the final layer. The final layer can be transformed into a multinomial distribution using the following softmax operation:
[0000]
p
(
l
=
k
|
q
;
θ
)
=
exp
(
∑
i
=
1
Q
λ
ik
q
i
+
a
k
)
Z
(
q
)
,
(
10
)
[0000] where l=k denotes the input been classified into the k-th class, and λ ik is the weight between hidden unit q i at the last layer and class label k.
[0042] Pursuant to an example, frame-level data can be used train a stack of RBMs in a generative manner, resulting in output of W RBM 305 . W RBM 305 may then be employed as a weight matrix for each full connection of input units that are obtained from a lower module in the DCN 100 .
[0043] Accordingly, the non-linear units 304 can receive values from the second set of input units 302 that are weighted by W RBM 305 . Based at least in part upon the first set of input units 202 and the second set of input units 302 as weighted by W RAN 206 and W RBM 305 , respectively, the non-linear units 304 in the hidden layer 116 can compute H. As has been described above, the non-linear units 304 are fully connected to a plurality of output units 306 in the top linear layer 118 of the second module, wherein such output units 306 are representative of targets for learning. It is desirable to learn the weight matrix U that defines weights of connections between the plurality of non-linear units 304 and the plurality of output units 306 .
[0044] The learning component 214 is configured to compute U 212 for the second module 104 based at least in part upon W RAN 206 , W RBM 305 , X (the values of the first set of input units 202 and the second set of input units 302 ), T, and H. Pursuant to an example, the system 300 may comprise a data store 308 that includes W RAN 206 , W RBM 305 , and T 310 , as these values can be pre-computed or known. A portion of X (the first set of input units 202 ) can also be retained in the data store 308 , as such values are static, while the remainder of x can be received from the immediately lower module in the DCN 100 . Based at least in part upon these values, the learning component 214 can compute U by way of convex optimization as described above.
[0045] Now referring to FIG. 4 , an exemplary system 400 that facilitates learning U for various modules in the DCN 100 through utilization of parallel computing is illustrated. The system 400 comprises a plurality of computing devices 402 - 404 . Each of the computing devices 402 - 404 can have an instance of the DCN 100 loaded thereon. A first computing device 402 can include a first data store 406 that comprises a first training batch 408 . The first training batch can include a significant amount of training data. A data receiver component 410 can receive data from the first training batch 408 , and provides the training to a first instance of the DCN 100 . The learning component can learn U for modules in the DCN 100 layer by layer, until U for all modules have been obtained.
[0046] The Nth computing device 404 comprises an Nth data store 412 that includes an Nth training batch 414 . The data receiver component 410 receives data from the Nth training batch 414 in the data store 412 and provides such training data to the instance of the DCN 100 on the Nth computing device 404 . The learning component 214 can learn U for all modules in the Nth instance of the DCN 100 . Accordingly, batch-mode processing can be undertaken in parallel across numerous computing devices, since the learning component 214 utilizes a convex optimization function to learn U. Final values for U may be set later in time as a function of values of U learned by the learning component 214 for the instances of the DCN 100 across the computing devices 402 - 404 .
[0047] With reference now to FIGS. 5-6 , various exemplary methodologies are illustrated and described. While the methodologies are described as being a series of acts that are performed in a sequence, it is to be understood that the methodologies are not limited by the order of the sequence. For instance, some acts may occur in a different order than what is described herein. In addition, an act may occur concurrently with another act. Furthermore, in some instances, not all acts may be required to implement a methodology described herein.
[0048] Moreover, the acts described herein may be computer-executable instructions that can be implemented by one or more processors and/or stored on a computer-readable medium or media. The computer-executable instructions may include a routine, a sub-routine, programs, a thread of execution, and/or the like. Still further, results of acts of the methodologies may be stored in a computer-readable medium, displayed on a display device, and/or the like. The computer-readable medium may be any suitable computer-readable storage device, such as memory, hard drive, CD, DVD, flash drive, or the like. As used herein, the term “computer-readable medium” is not intended to encompass a propagated signal.
[0049] With reference now to FIG. 5 , an exemplary methodology 500 that facilitates training a DCN in a batch-based manner is illustrated. The methodology 500 starts at 502 , and at 504 training data for training a deep convex network is received. As described above, the deep convex network comprises a plurality of interconnected modules, and each module includes at least one linear layer and at least one non-linear (hidden) layer. At 506 , the deep convex network is trained in a batch-based manner based at least in part upon the training data, wherein training the deep convex network comprises learning a weight matrix corresponding to output of the non-linear layer of at least one module in the plurality of interconnected modules. The methodology 500 completes at 508 .
[0050] Now turning to FIG. 6 , an exemplary methodology 600 that facilitates learning a plurality of weight matrices by way of convex optimization is illustrated. The methodology 600 starts at 602 , and at 604 speech training data is received. At 606 , a deep convex network is trained in a batch manner through utilization of the training data, wherein the deep convex network comprises a plurality of layered modules that each include a one-hidden-layer neural network. A hidden layer in a first module includes a plurality of non-linear units that are interconnected to a plurality of linear input units in a linear layer of a second module. Training the deep convex network includes learning a plurality of weight matrices corresponding to the plurality of layered modules, such that a weight matrix is learned for each layered module, and wherein the weight matrix is learned by way of convex optimization. The methodology 600 completes at 608 .
[0051] Now referring to FIG. 7 , a high-level illustration of an exemplary computing device 700 that can be used in accordance with the systems and methodologies disclosed herein is illustrated. For instance, the computing device 700 may be used in a system that supports ASR. In another example, at least a portion of the computing device 700 may be used in a system that supports learning weight matrices in a DCN by way of convex optimization. The computing device 700 includes at least one processor 702 that executes instructions that are stored in a memory 704 . The memory 704 may be or include RAM, ROM, EEPROM, Flash memory, or other suitable memory. The instructions may be, for instance, instructions for implementing functionality described as being carried out by one or more components discussed above or instructions for implementing one or more of the methods described above. The processor 702 may access the memory 704 by way of a system bus 706 . In addition to storing executable instructions, the memory 704 may also store a training data set, a validation data set, a DCN, etc.
[0052] The computing device 700 additionally includes a data store 708 that is accessible by the processor 702 by way of the system bus 706 . The data store 708 may be or include any suitable computer-readable storage, including a hard disk, memory, etc. The data store 708 may include executable instructions, a DCN, a training data set, a validation data set, weight matrices, etc. The computing device 700 also includes an input interface 710 that allows external devices to communicate with the computing device 700 . For instance, the input interface 710 may be used to receive instructions from an external computer device, from a user, etc. The computing device 700 also includes an output interface 712 that interfaces the computing device 700 with one or more external devices. For example, the computing device 700 may display text, images, etc. by way of the output interface 712 .
[0053] Additionally, while illustrated as a single system, it is to be understood that the computing device 700 may be a distributed system. Thus, for instance, several devices may be in communication by way of a network connection and may collectively perform tasks described as being performed by the computing device 700 .
[0054] As used herein, the terms “component” and “system” are intended to encompass hardware, software, or a combination of hardware and software. Thus, for example, a system or component may be a process, a process executing on a processor, or a processor. Additionally, a component or system may be localized on a single device or distributed across several devices. Furthermore, a component or system may refer to a portion of memory and/or a series of transistors.
[0055] It is noted that several examples have been provided for purposes of explanation. These examples are not to be construed as limiting the hereto-appended claims. Additionally, it may be recognized that the examples provided herein may be permutated while still falling under the scope of the claims. | A method is disclosed herein that includes an act of causing a processor to access a deep-structured, layered or hierarchical model, called deep convex network, retained in a computer-readable medium, wherein the deep-structured model comprises a plurality of layers with weights assigned thereto. This layered model can produce the output serving as the scores to combine with transition probabilities between states in a hidden Markov model and language model scores to form a full speech recognizer. The method makes joint use of nonlinear random projections and RBM weights, and it stacks a lower module's output with the raw data to establish its immediately higher module. Batch-based, convex optimization is performed to learn a portion of the deep convex network's weights, rendering it appropriate for parallel computation to accomplish the training. The method can further include the act of jointly substantially optimizing the weights, the transition probabilities, and the language model scores of the deep-structured model using the optimization criterion based on a sequence rather than a set of unrelated frames. | 6 |
BACKGROUND
1. Field
The disclosed subject matter relates to a self-raising headrest for a vehicle seat. More particularly, the disclosed subject matter relates to a headrest that self-raises in a fold-flat vehicle seat, whereby the headrest that is stowed against the seat upon folding of the seat returns to its extended position upon opening of the seat from the folded position to the unfolded position.
2. Brief Description of the Related Art
Passenger vehicles typically include a multitude of safety features to protect the occupants from harm during impact collisions. For example, seatbelts, airbags and active restraint systems have been employed in vehicles for many years. The safety features are designed to minimize the destructive forceful impact on the vehicle occupants that may be caused, for example, when a vehicle suffers a head-on collision, as well as providing protection when the vehicle is struck from behind in a rear-end collision. The amount and quality of such safety systems may vary among vehicle manufacturers, and most modern manufacturers also incorporate headrest restraints to protect the vehicle occupants in rear-end collisions. An effective headrest is one that is typically located directly behind the centerline of the occupant's head and is positioned no more than about two inches away from the head.
In a front-end collision, the vehicle's forward motion is abruptly stopped. The seat belts and airbags prevent the occupants from hurtling forward. The goal is to maintain the occupant in an upright position and to prevent his/her body from striking into hard surfaces, other occupants, or from being ejected out of the vehicle.
Conversely, in a rear-end collision, the impact forces are directed in the opposite direction. The vehicle is abruptly propelled forward, and the seated occupants are correspondingly thrown backward. Just as the seatbelt and/or airbag holds an occupant in the seat and restricts forward motion, a seatback and head restraint restricts rearward motion in a rear-end collision.
Importantly, the headrest should be positioned so that the occupant's head does not pivot over the headrest in a rearward direction. This pivoting action over the headrest could flex the upper spinal column. For example, an adjustable head restraint placed in a relatively lower position by a shorter person may not fit a subsequent, taller person whose head and upper spinal column can flex over the head restraint in a rear impact collision.
In U.S. Pat. No. 2,989,341, there is described a stationary reclining chair having a headrest that is extended to a pre-determined supporting position during the initial reclining movement of the chair. The reclining chair employs a combined guiding and actuating linkage in the form of a double arm actuating lever so that the pivotal mount moves in a prescribed arcuate path about the backrest pivot in response to the user's reclining movement. As the user sits in the upright chair and leans against the backrest, the corresponding force on the linkage engages the linkages and guiding mechanisms of the headrest to the extended position in order to support the back of the user's head. Further application of rearward force against the backrest of the chair causes the extended headrest and backrest to move as a single unit with no relative displacement between the backrest and headrest from the initial inclined position. Thus, the increase in angular relationship between the backrest and the chair seat does not change the relative position of the headrest in relation to the backrest in the further-reclined chair.
Also, PCT publication WO94/01302 provides a vehicle seat having a foldable backrest and a head restraint (i.e., headrest), where the headrest can be retracted into the backrest when folded down, and returned when the backrest is folded up. As the backrest is progressively folded down, a blocking device which normally maintains the backrest in an upright locked position is released, and a link arm pulls a yoke rod downwardly into the backrest, thereby retracting the headrest against the backrest. However, the device contains a significant limitation in that folding the vehicle seat upward returns the headrest to the “lowermost position of the adjustment range”, which must then be manually moved upward by hand to a higher adjustment position.
Further, U.S. Patent Publication No. US2002/0079723A1 discloses a mechanical actuating apparatus for a headrest mounted on a seat back which is able to be folded downward. The headrest is reportedly completely retracted from its pre-adjusted position and then restored to the original position when the seat back is folded upward. The traction device used is a Bowden cable, wherein the traction wire is connected to the headrest holder and allegedly counteracts the pulling force of an energy storing device which pulls the headrest into an extended position. The pivoting movement of the seatback is converted into a rolling-up or unrolling movement to extend or shorten a free length of the cable of the traction device. Unfortunately, the device is particularly limited by the use of such a Bowden cable traction mechanism, since the cable may slide out of position or become jammed.
Therefore, typical vehicle headrest restraints, including those described above, are deficient in their ability to provide a simple mechanism for a self-retracting headrest that minimizes clearance requirements for folding seatbacks. Moreover, a headrest restraint that returns to an extended position immediately upon unfolding of the backrest would be advantageous in providing greater safety for a user who can adequately adjust the headrest to match the user's head location as he/she sits in the vehicle seat, while simultaneously eliminating the situation where the user's head could pivot over the fully-retracted headrest during a vehicle collision.
SUMMARY
According to an aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus for a foldable vehicle seat comprising a headrest frame disposed at the upper end of the foldable vehicle seat, a recliner support bracket containing an upper channel and a lower channel, wherein said recliner support bracket is disposed in the rotational seatback of the foldable vehicle seat, a linkage having an upper end and a lower end, and a pivot point of the rotational seatback of the foldable vehicle seat, wherein the lower end of said headrest frame is operatively interconnected to the upper end of said recliner support bracket, the lower end of said recliner support bracket is operatively interconnected to the upper end of said linkage, and the lower end of said linkage is operatively interconnected to said pivot point, and wherein said linkage rotates together with the seatback about said pivot point of said rotational seatback and the rotation of said linkage causes said headrest frame to raise to an extended position.
In accordance with another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage pushes directly on the headrest frame.
In accordance with yet another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage contacts a spring and said spring in turn contacts the headrest frame to raise the headrest to the extended position.
In accordance with still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described further comprising a spring means for storing or releasing energy from folding or unfolding of said foldable seat and wherein said spring is interposed between said linkage and said headrest frame.
In accordance with another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus for a foldable vehicle seat comprising a headrest frame disposed at the upper end of the foldable vehicle seat, a recliner support bracket containing an upper channel and a lower channel, wherein said lower channel is formed in a substantially linear configuration, and wherein said recliner support bracket is disposed in the rotational seatback of the foldable vehicle seat, a linkage having an upper end and a lower end, and a pivot point of the rotational seatback of the foldable vehicle seat, wherein the lower end of said headrest frame is operatively interconnected to the upper end of said recliner support bracket, the lower end of said recliner support bracket is operatively interconnected to the upper end of said linkage, and the lower end of said linkage is operatively interconnected to said pivot point, and wherein said linkage rotates together with the seatback about said pivot point of said rotational seatback and the rotation of said linkage causes said headrest frame to raise to an extended position.
In still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage pushes directly on the headrest frame.
In yet another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said linkage contacts a spring and said spring in turn contacts the headrest frame to raise the headrest to the extended position.
In another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described further comprising a spring means for storing or releasing energy from folding or unfolding of said foldable seat and wherein said spring is interposed between said linkage and said headrest frame.
In still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus for a foldable vehicle seat comprising a headrest frame disposed at the upper end of the foldable vehicle seat, a recliner support bracket containing an upper channel and a lower channel, wherein said lower channel includes an angled configuration, and wherein said recliner support bracket is disposed in the rotational seatback of the foldable vehicle seat, a linkage having an upper end and a lower end; and a pivot point of the rotational seatback of the foldable vehicle seat, wherein the lower end of said headrest frame is operatively interconnected to the upper end of said recliner support bracket, the lower end of said recliner support bracket is operatively interconnected to the upper end of said linkage, and the lower end of said linkage is operatively interconnected to said pivot point, and wherein said linkage rotates together with the seatback about said pivot point of said rotational seatback and the rotation of said linkage causes said headrest frame to raise to an extended position.
In yet another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said headrest is automatically raised to a fully-extended position upon unfolding of said vehicle seat.
In another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said headrest is automatically lowered to a fully-retracted position upon folding of said vehicle seat.
In still another aspect of the disclosed subject matter, there is provided a self-raising headrest apparatus as herein described wherein said headrest is temporarily stalled and subsequently automatically raised to a fully-extended position upon unfolding of said vehicle seat.
Still other objects, features, and attendant advantages of the disclosed subject matter will become apparent to those skilled in the art from a reading of the following detailed description of embodiments constructed in accordance therewith, and taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosed subject matter of the present application will now be described in more detail with reference to exemplary embodiments of the apparatus and method, given only by way of example, and with reference to the accompanying drawings, in which:
FIG. 1 is a side view of a folded down vehicle seat according to an embodiment of the disclosed subject matter;
FIG. 2 is a side view of the vehicle seat of FIG. 1 in an unfolded state;
FIG. 3 is a magnified detail view of a self-raising headrest mechanism made in accordance with principles of the disclosed subject matter;
FIG. 4 is a magnified detail view of another self-raising headrest mechanism made in accordance with principles of the disclosed subject matter; and
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
Referring to the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures.
The foldable seat incorporating aspects according to the presently disclosed subject matter may be present in any portion of the vehicle including the vehicle front row, i.e., where the driver or passenger seat is situated. The foldable seat may also be incorporated into one or more seats located in the second row of the vehicle, which is the row directly located behind the front row driver's seat. Similarly, the foldable seat may comprise one or more seats located in the third or subsequent rows of the vehicle. Accordingly, the vehicle seat could be in a sedan, a sport utility vehicle, a van, a pickup truck, or any other type of vehicle that can incorporate one or more foldable seats.
FIG. 1 shows a foldable vehicle seat in the folded down position. The seat base 1 rests on the horizontal seat frame 2 , which is integrally fixed to the seat attachment rails 3 , 3 . The seat attachment rails 3 , 3 can be mounted onto the vehicle frame or floor structure (not shown) so that the entire foldable seat is securely attached to the vehicle. The seat 6 which a user sits on is movably attached to the backrest 4 at a second pivot axle 9 , whereby the second pivot axle 9 permits the seat 6 to travel horizontally to a limited degree toward the rear of the seat base 1 as the backrest 4 is rotated in direction B from a folded position (as in FIG. 1 ) to an upright position (as shown in FIG. 2 ).
In the folded position in FIG. 1 , the backrest 4 has been rotated downward from an upright position by rotating the backrest 4 about the pivot wheel 7 and its associated first pivot axle 8 , in a counterclockwise direction (i.e., direction opposite to direction B). This pivot wheel 7 has a first pivot axle 8 which serves to rotatably connect the backrest 4 to the seat base 1 , while simultaneously allowing the backrest 4 to fold downward into a suitable position for stowing the foldable seat. The headrest 5 is shown in its fully retracted position as it nests partially or fully against the backrest 4 . This stowable position may also be referred to as the folded position.
FIG. 1 shows a support bracket 14 that includes pins 12 and 15 that are configured to ride in a lower channel 17 and an upper channel 18 , respectively. The relatively highest portion 13 b of lower channel 17 shows the maximum height adjustment position of the second linkage pin 12 , and the highest portion 16 b of the upper channel 18 similarly shows the maximum height adjustment position of the upper adjustment pin 15 .
The second linkage pin 12 is also connected to the linkage member 10 , and the first linkage pin 11 connects the linkage member 10 to the seat base 1 . As the backrest 4 is rotated in direction B, which corresponds to an unfolding or raising of the seat from the folded or stowed position, the lower end 4 a of the backrest 4 pivots about the first pivot axle 8 , and the pivot wheel 7 rotates in a clockwise direction (direction B). Upon further rotation of the backrest 4 in direction B, the first linkage pin 11 restricts the linkage member 10 from any downward movement toward the seat frame 2 . Rather, the second linkage pin 12 is progressively driven within the lower channel 17 in a generally upward direction toward the highest portion 13 b of the lower channel 17 . The upper adjustment pin 15 , which may be optionally present in the embodiment, is also driven in a generally upward direction toward the highest portion 16 b of the upper channel 18 . The recliner support bracket 14 is correspondingly driven upward with the pins 12 and 15 , and the headrest 5 is thereby extended upward as the backrest 4 is unfolded.
The upper and lower channels, 18 and 17 , respectively, may each independently be a channel having smooth edges for infinite adjustments of the upper adjustment pin 15 and the second linkage pin 12 within the particular channel. Alternatively, either one or both of the channels ( 18 , 17 ) may have ridges, contoured edges, or controlled stopping elements along the interior edges, whereby the headrest 5 may be adjusted to a level corresponding to the individual ridge points, contoured edges, or stopping elements. One or more of the upper and lower channels ( 18 , 17 ) may have polished or lubricated edges, or may have linings of various materials to facilitate relatively smooth or constant movement of the second linkage pin 12 or upper adjustment pin 15 as it travels in the particular channel. In one embodiment, there may be a single channel at the upper or lower region of the recliner support bracket 14 only. However, a second or more additional channels can be provided for added direction and to provide positive stop limits for the headrest.
The linkage member 10 as shown is connected at its lower end via a first linkage pin 11 to the seat base 1 . The linkage member 10 is also connected at its upper end via a second linkage pin 12 to the recliner support bracket 14 for travel through the lower channel 17 . The second linkage pin 12 is adjustable and is able to travel within the confines of the lower channel 17 from the lowest portion 13 a of the lower channel 17 to the highest portion 13 b of the lower channel 17 . The channel can be provided in a separate linkage member or other portion of the seat structure. The degree of travel enables a user to adjust the headrest 5 to a desired vertical position to support the back of the user's head.
The action of folding down the backrest 4 in order to stow the entire foldable seat yields a sequence of events that is opposite the procedure described above. For example, as the backrest 4 is rotated downward, the pivot wheel 7 and first pivot axle 8 rotate in a counterclockwise direction. The linkage member 10 also rotates in a generally counterclockwise direction, causing the second linkage pin 12 to descend within the lower channel 17 toward the lowest portion 13 a of the lower channel 17 . Similarly, the upper adjustment pin 15 is correspondingly drawn downward in the upper channel 18 toward the lowest portion 16 a of the upper channel 18 . This action causes the headrest 5 to be retracted or drawn downward as the upper adjustment pin 15 and the second linkage pin 12 are both simultaneously drawn downward as well. In an embodiment where the optional upper adjustment pin 15 is not included, only the second linkage pin 12 travelling within the lower channel 17 operates to retract the headrest 5 as the backrest 4 is folded downward. Further rotation of the entire foldable seat toward the stowed position eventually causes the headrest 5 to be fully retracted into the stowable position. Thus, as shown in FIG. 1 , the headrest 5 is stowed in its lowermost (or fully retracted) position in relation to the backrest 4 .
In FIG. 2 , the foldable seat is shown in its unfolded or upright position. The headrest 5 has been extended in direction A to its maximum height. The backrest 4 and corresponding recliner support bracket 14 are also shown in their generally upright position. The second linkage pin 12 of linkage member 10 is shown in its uppermost adjustment position within the lower channel 17 , and the optional upper adjustment pin 15 is correspondingly shown in its uppermost adjustment position within upper channel 18 . The linkage member 10 connecting the recliner support bracket 14 to the headrest 5 is also shown in its most upright position relative to the backrest 4 .
In the folded seat position as shown in FIG. 1 , the seatback has been rotated in a direction opposite to direction B, toward the seat 6 . The headrest 5 is shown in the fully retracted position. The upper pin 15 and the lower pin 12 both reside in their respective lowermost adjustable positions, 16 a and 13 a , respectively, in the upper and lower channels 18 and 17 , respectively. The corresponding linkage member 10 is also shown in its lowermost adjustment position, due to the folded down position of the backrest 4 .
FIG. 3 shows an example of the straight lower channel 17 a . This straight lower channel 17 a is configured for uniform movement of the first linkage pin 11 toward an upward direction without any great degree of horizontal movement of the first linkage pin 11 . In this exemplary configuration, as the seat is unfolded, there is a continuous proportional raising of the headrest (not shown) as the linkage member 10 and associated first linkage pin 11 drive the recliner support bracket 14 in an upward direction. In turn, the recliner support bracket 14 causes the headrest to be pushed upward. As the first linkage pin 11 reaches the highest portion 13 b of the straight lower channel 17 a , then the recliner support bracket 14 will correspondingly drive the headrest to its maximum extended position.
As shown in FIG. 4 , the seat can include structures that can provide a stall period during which the headrest is not driven upward during the initial unfolding of the seat. For example, the lower channel 17 b may optionally be configured in an angled manner which provides a stall zone 17 c as a portion of this angled lower channel 17 b . The stall zone feature operates such that the headrest does not raise during the initial stages of raising the seatback. This stalled or delayed raising of the headrest avoids, for example, the rear of any other interior vehicle seat located immediately in front of the foldable seat, or additional interior feature such as a console, until the seatback is unfolded (raised) to a point where the headrest would clear the obstruction. The “stall zone” is that portion of the angled lower channel corresponding to region 17 c in FIG. 4 .
As the foldable seat which has the incorporated stall zone 17 c is raised, the first linkage pin 11 travels in a generally rearwardly direction within the angled lower channel 17 b . Once the first linkage pin 11 reaches the interior angle transition point 13 c as shown in FIG. 4 , the linkage member 10 continues to travel in a generally rearwardly direction, but gradually proceeds in a generally upward direction simultaneously within the angled lower channel 17 b . The angled lower channel 17 b enables the first linkage pin 11 to travel rearwardly as the seat is unfolded, whereby the linkage member 10 also travels rearwardly to temporarily stall or delay the raising of the headrest. Upon unfolding of the seat, the linkage member 10 and associated first linkage pin 11 do not immediately push the recliner support bracket in an upward motion, but rather the linkage member 10 and associated first linkage pin 11 travel the distance of stall zone 17 c from the lowest portion of the angled lower channel 17 b until reaching the interior angle transition point 13 c of the angled lower channel 17 b , wherein the first linkage pin 11 then begins to drive the recliner support bracket 14 in an upward direction and causes the headrest to be pushed upward. Once the first linkage pin 11 reaches the highest portion 13 b of the angled lower channel 17 b , then the recliner support bracket 14 will in turn have driven the headrest to its fully extended position.
As indicated above, a seat that includes the above-described stall zone 17 c may be applied in a second or third row foldable seat where the headrest raising is desirably stalled or temporarily delayed as the seat is unfolded. In the initial stages of unfolding the seat, the linkage member is initially driven generally rearwardly in the stall zone 17 c as described. By temporarily delaying or “stalling” the raising of the headrest, interior obstructions may be cleared and the headrest then raises to its fully extended position as the seatback is further opened beyond the stall portion of the adjustment channel. As the seatback reaches the fully unfolded position, the headrest also reaches its maximum extended position.
The headrest can be adjusted to a specified position relative to the bracket 14 after the user has unfolded the seat through the use of typical adjustment mechanisms located between the headrest 5 and the linkage bracket 14 .
While certain embodiments of the disclosed subject matter are described above, it should be understood that the disclosed subject matter can be embodied and configured in many different ways without departing from the spirit and scope of the disclosed subject matter. For example, the interface between the linkage member and the recliner support bracket can be configured such that the components are at varying angles with respect to each other and include various connecting structures for connecting to the other vehicle seat components. Furthermore, the specific linkage as shown is not critical. Other various linkages can be used to provide similar kinetic motion to the seat, backrest and headrest.
The embodiments described above provide for direct movement of the headrest 5 via linkage bracket 14 . However, it is contemplated that the linkage bracket 14 could release a spring lock when the linkage bracket 14 is moved close to its upward most position. The spring lock would releases a spring that moves the headrest 5 outward by force of the spring. The headrest 5 could then be stowed back away by pushing it back down in the backrest 4 against the compressive force of the spring until the spring lock is again engaged.
Further, while the disclosed subject matter has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the disclosed subject matter. Each of the aforementioned documents is incorporated by reference herein in its entirety. | A vehicle seat that is foldable can include a linkage mechanism for operatively withdrawing the headrest during fold down procedures and automatically extending the headrest to a use position during unfolding procedures of the seat. | 1 |
TECHNICAL FIELD
This invention relates generally to aircraft and more particularly to a particular arrangement of components in aircraft design for providing increased directional stability at high angles of attack, a means to reduce the overall drag of the aircraft, and the capability to build an aircraft structure having a greater stiffness for a given aircraft weight.
BACKGROUND ART
Many types of aircraft are required to be highly maneuverable to perform their functions. Examples include aerobatic light aircraft, trainers, and fighter or attack aircraft. Such aircraft are occasionally required to operate in flight regions where the angle-of-attack is large. Angle-of-attack refers to the incidence of an aircraft with respect to its velocity vector. For aircraft to be able to fly safely at high angle-of-attack and perform maneuvers, the aircraft must be stable and controllable. In some modern aircraft, stability is provided by artificial means. Artificial stabilization may be achieved with control effectors, which are used to generate forces and moments to oppose unwanted aircraft motions. While artificial stabilization may be effective, it has some unfavorable side effects. For example, as the level of instability increases, the amount of control moment required to stabilize the vehicle increases. Beyond a certain level of instability, sufficient control moments may not be available, and the aircraft can experience a departure from controlled flight. Even if sufficient control authority is available to prevent unwanted motions, artificial stabilization results in less control power available to maneuver the aircraft. A loss of available control power results in a loss in mission effectiveness. Artificial stabilization is not an option with most low cost aircraft since such aircraft do not have computers and control effector designs required to add artificial stability. It is noted that a loss in inherent vehicle stability occurs with virtually all aircraft at high angles-of-attack.
While stability in pitch axis can be altered with careful design and control of aircraft center-of-gravity, directional stability must be provided by stabilizing surfaces or by artificial means. Directional stability is defined as the tendency of an aircraft to weathercock into the wind when disturbed. When used without reference to an axis system, directional stability is assumed to be in the flight path or stability axis system. Although other axis systems may be used for convenience, the flight path or stability axis reflects the motion of the aircraft. Flight path directional stability is composed of two parameters, i.e. body axis directional stability and body axis lateral stability or dihedral effect. The body axes of a vehicle are mutually perpendicular and are normally aligned along the fuselage axis, the approximate plane of the wing, and normal to the other two. Body axis directional stability refers to the tendency of the fuselage to point back into the wind when disturbed from equilibrium. Body axis lateral stability refers to a tendency for the aircraft to roll in a direction to eliminate any side component of the relative wind. If an aircraft is at an angle-of-attack other than zero, flight path axis directional stability is a combination of both body axis directional and lateral stability and is calculated from equation 1 as follows: ##EQU1## From equation 1 it is apparent that both body axis directional stability and body axis lateral stability contribute significantly to flight path directional stability when angle-of-attack is large. This implies that aircraft stability can be improved by any device or component that increases either or both values. It is highly desirable to provide inherent directional stability to maximize the amount of control power available to perform out of plane maneuvers, such as rolling, and to prevent rapid aircraft departures from controlled flight, which often lead to spins. Current and prior design practice has relied on large fixed aerodynamic surfaces mounted on the aircraft fuselage to stabilize the aircraft. However, such surfaces lose their effectiveness at large incidence angles.
The current invention relies on a novel arrangement of wing and tail surfaces to provide inherent directional stability even at high angle-of-attack. The invention achieves these results by joining the wing and horizontal tail panels with canted or vertical stabilizing surfaces that operate effectively over a wide angle-of-attack and sideslip range and provide stabilizing moments about both directional and lateral axes. These stabilizing moments will insure that the aircraft remains directionally stable, or nearly so, to much higher angles-of-attack than is current practice.
Directional stability has typically been provided by a single vertical tail located on the centerline of an aircraft at or near the rear of an aircraft fuselage. The vertical tail provides directional stability by acting as a lifting surface. When an aircraft is perturbed in a manner such that sideslip occurs, a local angle-of-attack occurs in the plane of the vertical tail. The local angle-of-attack generates a lifting force on the tail panel and creates a moment about the center-of-gravity of the aircraft that opposes the sideslip and returns the aircraft to a zero sideslip condition. The larger the tail surface area, the larger the moment that is generated, and the greater the directional stability.
Although the use of a vertical tail to provide directional stabilization has proven effective over the years, a vertical tail presents serious disadvantages at high angles-of-attack. As aircraft angle-of-attack increases, the fuselage of the aircraft tends to block airflow to the vertical tail. The blockage of airflow reduces the effectiveness of the vertical tail. If angle-of-attack exceeds a certain value, this value being dependent on the vehicle in question, the flow over the fuselage separates, or detaches. Under a detached flow condition, not only is the tail partially blocked by the fuselage, but flow separation results in a region of low energy air in the vicinity of the vertical tail, which further reduces the effectiveness of the tail.
An additional factor resulting in reduced effectiveness of the tail is the aft sweep of a typically configured tail. High performance aircraft typically employ swept wing and tail surfaces to reduce drag at transonic and supersonic Mach numbers. Due to structural considerations, these surfaces, including the vertical tail panel, are usually swept aft. For a vertical tail, aft sweep results in much of the airflow at high angles-of-attack being directed along the span of the surface of the tail rather than along the chord line of the tail, which further reduces effectiveness of the tail.
A single, centerline vertical tail has additional disadvantages for modern high performance aircraft. Highly swept surfaces at the front of typical modern high performance aircraft are intended to generate vortices, or regions of high energy rotational flow, at high angles-of-attack. These vortices have been shown to interact with downstream aircraft components, sometimes in an unfavorable manner. Using the F-16 aircraft as an example, under certain conditions, the vertical tail actually contributes a destabilizing directional moment.
Several modern high performance fighter aircraft employ twin vertical tails to partially overcome the disadvantages of a single tail surface. For a given aircraft configuration, the total area of the twin panels is usually more than a single panel configured to provide equivalent directional stability at low angles-of-attack. In all known current applications, the twin vertical tails are mounted on the fuselage. Therefore, at high angle-of-attack, the fuselage still tends to block a portion of airflow to the tail surfaces. Additionally, energy of the flow in the vicinity of the tail surfaces is reduced. On aircraft configurations set up to generate strong vortex flow fields, twin tail surfaces can reduce but not eliminate the effect of unfavorable interference due to vortex impingement and interaction. An additional problem encountered by fuselage mounted twin vertical tail configurations is the loss of effectiveness due to sweep back.
Other arrangements have been proposed or used to provide inherent directional stability, but most of these are intended for low performance aircraft operating at low angle-of-attack. Examples of other arrangements include twin horizontal stabilizer mounted vertical surfaces (e.g., the B-24 bomber of World War II), boom mounted tails (e.g., the P-38 fighter aircraft), and a wing tip mounted vertical tail (e.g., the Beechcraft Starship and numerous light plane designs). All of these concepts attempt to improve upon conventional means of stabilization. None are entirely successful. A new approach is required to provide directional stability at high angles-of-attack.
Historical results have shown that aerodynamic advantages exist for the biplane configuration. A biplane consists of two lifting surfaces or panels separated in height and sometimes longitudinal location. Test results have shown that the effective aspect ratio of a biplane is higher than that of a monoplane of the same span. The change in effective aspect ratio has been shown to be a function of main surface wing span, vertical distance between the lifting surface panels, ratio of the span of one panel to that of the other, and relative lengthwise positioning of the two panels, i.e., stagger.
Attempts have been made in modern designs to make use of the benefits of the biplane. Such attempts have largely consisted of designs that join together tips of forward and aft lifting surfaces. These attempts have generally not been successful for a number of reasons. First, the direct joining of the tips of two lifting surfaces results in no vertical separation between the panels at the tips. Test results indicate that a condition of no vertical separation between lifting surfaces eliminates the desired biplane effect. Second, joining of the lifting surfaces limits design options. For example, if the tips of the lifting surfaces are joined, it is usually necessary for both lifting surfaces to have the same span, which results in a tandem wing configuration that is not ideal for all applications.
An additional attempt to make use of the benefits of a biplane is a boxplane configuration. A boxplane configuration joins upper and lower wing panels in a rigid structure. However, a box plane arrangement uses a conventional horizontal stabilizer and does not attempt to use the joining members as vertical stabilizers. Other modern designs have attempted to use a biplane arrangement for supersonic vehicles. These designs may take advantage of favorable shock wave interaction at supersonic Mach numbers. Due to the nature of shock waves and their inclination with respect to an aircraft's direction of motion, a supersonic biplane arrangement is not suitable for a conventional wing and tail arrangement where the separation of wing and tail surfaces is set by considerations of aircraft balance and control capability rather than simply being determined by shock wave inclination at a design Mach number.
SUMMARY OF THE INVENTION
Consequently, one object of this invention is to improve on the prior art of providing directional stability at high angles-of-attack for flight vehicles. This goal is achieved by a unique arrangement of aircraft components including the wing, horizontal stabilizers, and vertical stabilizers. In addition to greatly improving high angle-of-attack directional stability, application of this invention results in a flight vehicle configured as and behaving in a manner similar to that of a biplane, thereby increasing the effective aspect ratio of the wing and reducing the induced drag of the aircraft.
A further advantage of this invention is that by joining all major lifting surfaces into one unit, an aircraft structure can be made stiffer for a given aircraft weight. Conversely, the weight of an aircraft can be reduced for a given stiffness.
A further object of this invention is to provide for a component arrangement that enables the vehicle to behave aerodynamically in the manner of a biplane, with an increase in effective aspect ratio of the wing and a corresponding reduction of the drag due to lift of the configuration.
In a preferred embodiment, the primary lifting surface, or wing, is located in a conventional position ahead of a horizontal tail and is mounted in a high position on the fuselage, that is, near the top of the fuselage. The horizontal tail surfaces, or horizontal stabilizers, are mounted behind the wing near the rear of the aircraft. The horizontal stabilizers are mounted in a low position on the fuselage, i.e., near the fuselage bottom. The directionally stabilizing surfaces consist of two aerodynamically configured panels joining the tips of the wing and horizontal stabilizer on each side of the aircraft. For simplicity and for historical reasons, the panels that join the tips of the wings and horizontal stabilizers will be referred to throughout this disclosure as vertical stabilizers although they may be also considered directional stabilizers. It is noted, however, that the orientation of the vertical stabilizers is not necessarily vertical, but may be canted out at the top. The arrangement of wing, horizontal stabilizers, and vertical stabilizers therefore forms a closed box structure. The required vertical separation between the wing and horizontal stabilizer causes the vehicle to behave in a manner of a biplane, with benefits as described above. The closed box configuration additionally produces a stiffer structure than a typical arrangement of aircraft components where the wing, horizontal stabilizer, and vertical stabilizer(s) are cantilevered out in space.
The preferred arrangement of this invention is a wing having a span equal to or greater than the span of a horizontal stabilizer. Such an arrangement forces the vertical joiner panels or vertical stabilizers to be either perpendicular to the approximate plane of the wing or canted out at the top. Since the wing is ahead of the horizontal tail, the vertical stabilizers joining the wing and tail are inclined to produce a forward aerodynamic sweep. Note that such an arrangement is in contrast to a typical arrangement for high speed vehicles where the sweep of lifting surfaces is traditionally in the aft direction.
In practice, the unique configuration of applicant's invention results in desirable flight characteristics. When an aircraft utilizing applicant's invention encounters a disturbance such as side slip, or a sideways velocity component at low angle-of-attack, incidence to the airflow develops on each panel of the vertical stabilizers. This incidence can be transformed to an angle-of-attack on a vertical stabilizer approximately equal to the sideslip angle times the sine of the dihedral angle of the vertical stabilizer. Dihedral angle is defined as the angle between the reference plane of the aircraft and a plane along the span of the vertical stabilizer. The sideslip perturbation results in an incremental force being generated normal to the plane of each vertical stabilizer. The incremental force is in addition to any side-to-side symmetric force which would occur on the panel during normal operation without sideslip. Since the center of pressure of the incremental force due to sideslip lies behind the center of rotation or center-of-gravity of the aircraft, the net effect is to produce a moment on the aircraft which tries to reduce the sideslip and roll the vehicle away from the sideslip. The first effect of reduction of sideslip is known as "body axis directional stability". The second effect is known as "body axis lateral stability". The net effect of the vertical stabilizers is to stabilize the aircraft in sideslip as desired.
If angle-of-attack is not zero, then both body axis directional stability and body axis lateral stability contribute to flight path directional stability. For the present invention, the moment components generated by the vertical stabilizers provide stabilizing moments about both axes. If the vertical stabilizer panels are indeed vertical (i.e., approximately perpendicular to the plane of the wing), then a directionally stabilizing moment is generated but not a laterally stabilizing moment.
The improvement provided by this invention is its effect at high angles-of-attack where a conventional vertical tail loses its effectiveness. In an embodiment of the invention where the vertical surfaces are canted outboard, the total forces on the panel will typically act upwards in a symmetric condition, i.e. when no sideslip is present. The incremental force introduced on each panel tends to stabilize the aircraft both directionally and laterally.
Several differences are apparent between the two wing mounted vertical surfaces and the single centerline vertical tail found on conventionally configured aircraft. First, in the two wing mounted vertical surfaces embodiment, the fuselage tends to block air flow to the downwind vertical stabilizer panel. While the incremental force on the downwind panel is still stabilizing, the total force acting normal to the surface of the downwind panel attempts to rotate the aircraft in the wrong or destabilizing direction if the downwind panel has geometric dihedral and carries an aerodynamic upload. However, the upwind panel provides a stabilizing moment, both from the basic force carried on the panel at high angles-of-attack as well as the incremental force due to sideslip. Therefore, any blockage of the downwind panel due to the presence of the fuselage actually results in an improvement in directional stability, since the effect of the destabilizing moment is reduced.
The upwind vertical stabilizer panel operates in undisturbed air away from the influence of the fuselage. The capability of operating in undisturbed air contrasts with conventional single or multiple vertical stabilizer panels mounted on the fuselage. For conventional arrangements, blockage renders vertical stabilizers ineffective at high angles-of-attack resulting in a loss of directional stability. In the current invention, the aerodynamic surface that provides directionally stabilizing moments (i.e., the upwind stabilizer panel) is well away is from the fuselage in a region of relatively undisturbed air and can continue to be effective at virtually any angle-of-attack.
Second, the arrangement of components of this invention requires that the wing be located in a position higher than and forward of the horizontal stabilizer. Consequently, the vertical stabilizers must be swept forward aerodynamically. As angle-of-attack increases, a component of flow velocity normal to the leading edge increases for the vertical stabilizers of this invention. This increases the aerodynamic effectiveness of the surfaces. The increase in aerodynamic effectiveness due to the forward sweep of the vertical surfaces contrasts with the result of the more typical unswept or aft swept vertical stabilizing surfaces employed on other aircraft where an increased angle-of-attack results in more of a local velocity component being directed along the span of the vertical surface, resulting in a loss in aerodynamic efficiency.
Preferably, the vertical stabilizers have a straight leading edge extending from a leading edge of the wing to a leading edge of one of the horizontal stabilizers. Additionally, each of the vertical stabilizers have a straight trailing edge extending from a trailing edge of the wing to the trailing edge of the horizontal stabilizers. The vertical stabilizers also preferably have a chord that is substantially constant from a lower end to an upper end.
It is envisioned that the implementation of this invention in the design of a particular flight vehicle would be tailored to the overall design requirements, the operating angle-of-attack range desired, and other factors. This invention can be applied to any flight vehicle, aircraft or missile. It is appropriate for everything from a high performance, supersonic fighter aircraft to low speed vehicles powered by piston or turboprop engines driven by a propeller.
Other and further features and objects of the invention will be more apparent to those skilled in the art upon a consideration of the appended drawings and the following description wherein several typical installations are shown and one constructional form of apparatus for carrying out the invention are disclosed. This invention consists of the construction, combination, and arrangement of parts all as in hereinafter more fully described, claimed, and illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an aircraft having a structure wherein the fuselage, wing, horizontal stabilizers and vertical stabilizers are arranged in accordance with the invention.
FIG. 2 is a front view of the wing, horizontal stabilizers and vertical stabilizers arranged in accordance with the invention.
FIG. 3 is a side view of an aircraft having an arrangement of fuselage, wing, horizontal stabilizers and vertical stabilizers in accordance with the invention.
FIG. 4 is a graphical representation of the relative effectiveness of the vertical stabilizers of this invention compared to the stabilizing surface of a conventional single centerline vertical tail.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, shown is an aircraft designated generally 10. The components of aircraft 10 include fuselage 12 having a top 14 and a bottom 16, and right wing 18 and left wing 20, which are affixed to fuselage 12. Right wing 18 has right wing tip 22. Left wing 20 has left wing tip 24. Proximate fuselage bottom 16, are right horizontal stabilizer 26 and left horizontal stabilizer 28, which are affixed to fuselage 12. Right horizontal stabilizer 26 has right horizontal stabilizer tip 30 and left horizontal stabilizer 28 has left horizontal stabilizer tip 32. Spanning between right wing tip 22 and right horizontal stabilizer tip 30 is right vertical stabilizer 34. Spanning between left wing tip 24 and left horizontal stabilizer tip 32 is left vertical stabilizer 36.
In this embodiment, inlet 38 feeds two rear mounted engines which exhaust through nozzles 40. Vertical stacking of the engines results in vertical separation 42 of wings 18 and 20 with respect to horizontal stabilizers 26 and 28, which can be seen most clearly in FIG. 2.
Referring now to FIG. 2, horizontal stabilizer span 44 is approximately seventy percent of wing span 46. Therefore, vertical stabilizers 34 and 36 are canted outward toward the top as can be more clearly seen in FIG. 2.
Referring back to FIG. 1, wings 18 and 22 use typical trailing edge devices 48 such as outboard ailerons and inboard trailing edge flaps. The embodiment of the invention shown in FIG. 1 is an example of a subsonic trainer aircraft. Therefore, elevators 50 are used on the trailing edges of horizontal stabilizers 26 and 28. Each trailing edge of horizontal stabilizers 26, 28 has an inboard junction at fuselage 16 and an outboard junction at the tip of each horizontal stabilizer 26, 28. As shown in the drawings, the inboard junction is no further aft than the outboard junction. In the drawings, the outboard junction of the trailing edge of each horizontal stabilizer 26, 28 is farther aft than the inboard junction. For supersonic application, all moving horizontal stabilizers may be desirable. Movable rudders 52 are located on the trailing edges of vertical stabilizers 34 and 36 to provide control about the yaw axis.
Referring back to FIG. 2, a front view of aircraft 10 is shown. The direction of relative wind is designated by relative wind component vector 54. For a condition of no side slip velocity, relative wind component vector 54 is zero. In a condition of no side slip, right vertical stabilizer 34 and left vertical stabilizer 36 may carry a small load as indicated by right vertical stabilizer load vector 56 and left vertical stabilizer load vector 58. In the presence of a side velocity that produces a side slip angle, an incidence angle is produced on right vertical stabilizer 34 and left vertical stabilizer 36 that generates right vertical stabilizer incremental force 60 and left vertical stabilizer incremental force 62. Incremental forces 60 and 62 produce a moment or twisting reaction about directional axis 64 and lateral axis 66, which may be more easily seen in FIG. 3. Center of gravity 68 is the reference point for the moments. Forces acting on right vertical stabilizer 34 and left vertical stabilizer 36 act behind center of gravity 68 since vertical stabilizers 34 and 36 are located towards the rear of the vehicle. Therefore, the resulting moment about directional axis 64 is in a direction that will try to point aircraft 10 into the side velocity, i.e. reduce the side slip angle. This is known as directional stability, thus vertical stabilizers 34, 36 may be referred to as directional stabilizers. The resulting moment about lateral axis 66 tends to rotate wings 18 and 22 such that the downwind wing moves downward. This is referred to as lateral stability.
Referring back to FIG. 2, right net normal force 70 is the total force acting on right vertical stabilizer 34. Left net normal force 72 is the total force acting on left vertical stabilizer 36. Net normal forces 70 and 72 are the total forces acting on vertical stabilizers 34 and 36 due to the incidence of the aircraft and the side slip angle. Since a downwind panel may be partially blocked by fuselage 12, any loss in efficiency of the downwind surface is actually beneficial to the directional stability of aircraft 10.
To provide some of the induced benefits of a biplane configuration and to insure adequate surface area of vertical stabilizers 34 and 36, the ratio of vertical separation distance 42 to wing span 46 cannot be too small. A minimum value of 0.15 is recommended. In the preferred embodiment, the ratio of vertical separation distance to wing span ranges from values of 0.2 to 0.25. Although there is no upper limit on the height to span ratio, design considerations will typically limit the height to span ratio to no more than 0.5 to 0.6. Additionally, although both wings 18 and 22 and horizontal stabilizers 26 and 28 are shown flat, i.e. without geometric dihedral, such dihedral (gull wing up or down) in either surface is permissible. If wings 18 and 22 or horizontal stabilizers 26 and 28 possess geometric dihedral, then vertical separation 42 should be defined by the average vertical distance between wings 18 and 22 and horizontal stabilizers 26 and 28. Note that changes in the values of the height span parameter also impact the inclination of vertical stabilizers 34 and 36.
In FIG. 2, geometric dihedral angle 74 is approximately 52 degrees. However, geometric dihedral angle 74 may be 90 degrees wherein vertical stabilizers 34 and 36 are vertical. Preferably, geometric dihedral angle 74 should range from 45 to 90 degrees. Preferably, vertical stabilizers 34 and 36 should be vertical or canted outboard as shown. An inboard cant is not preferred since an inboard cant of vertical stabilizers 34 and 36 results in a generation of a destabilizing lateral moment with side slip. When right vertical stabilizer 34 and left vertical stabilizer 36 are positioned vertically, i.e. where geometric dihedral angle 74 is 90 degrees, little or no lateral moment will be generated. When geometric dihedral angle 74 is 45 degrees, horizontal stabilizer span 44 is one half of wing span 46.
Referring now to FIG. 3, shown is a side view of aircraft 10. Left wing 20 is shown positioned proximate fuselage top 14. Left horizontal stabilizer 28 is shown positioned proximate fuselage bottom 16 and rearward of left wing 20. Aerodynamic center or center of lift 76 of left vertical stabilizer panel 36 is shown positioned behind center of gravity 68 of aircraft 10. By positioning center of lift 76 behind center of gravity 68, incremental forces on left vertical stabilizer 36 due to side slip will create a stabilizing directional moment.
The ratio of horizontal stabilizer tip cord 78 to wing tip cord 80 should be equal to or greater than one. By providing a horizontal stabilizer tip cord to wing tip cord ratio of greater than one, forces acting on vertical stabilizer 36 will stabilize rather than destabilize aircraft 10. However, in an extreme case where both wing 20 and horizontal stabilizer 36 are mounted well aft such that aerodynamic center 81 of wing 20 is near or behind center of gravity 68 of the aircraft, this geometric requirement can be waived. It has been found that it is important to keep forces generated on vertical stabilizers 34 and 36 behind center of gravity 68 of aircraft 10.
Referring now to FIG. 4, a graphical representation of the effectiveness of a conventional center line vertical tail for providing directional stability is compared to the effectiveness of providing directional stability by means of twin vertical stabilizer panels of the present invention. Flight path axis directional stability is plotted on the y-axis versus angle-of-attack, which is plotted on the x-axis. It can be seen from the graph that the effectiveness of the conventional surface drops rapidly at angles-of-attack greater than 25 degrees. Above 35 degrees, the vertical stabilizer actually destabilizes the vehicle. The data for the proposed invention show that wing mounted vertical stabilizers 34 and 36 of the invention become more effective as angle-of-attack increases and remain effective to the highest angle-of-attack shown in the data. The results shown are normalized to the value of stabilizing moment produced by each configuration at zero degrees angle-of-attack. The absolute value is different between the two configurations because of differences in surface size and geometry.
The vertical stabilizers act to provide directional stability along the flight path and are much more effective at high angles-of-attack than conventional single or multiple vertical stabilizers. This arrangement of the invention achieves these results by providing vertical stabilizers that are less strongly influenced by fuselage blockage at high angles-of-attack and providing a component geometry in which the effects of fuselage blockage actually improve the overall effectiveness of the vertical stabilizers instead of decreasing the effectiveness of the vertical stabilizers. Additionally, stabilizing moments are provided in both the body axis directional and lateral axes, both of which contribute to flight path axis directional stability at high angles-of-attack. Finally, by providing vertical stabilizers having a forward sweep, wherein the forward sweep increases a component of flow velocity normal to the leading edge of the vertical stabilizer, the aerodynamic efficiency of the vertical stabilizers improves as angle-of-attack increases.
The invention provides directional stability by passive means without control augmentation and is suitable for application to new designs of any performance level ranging from slow speed, highly maneuverable aerobatic aircraft to supersonic fighters.
The vertical separation between the wing and horizontal tail and the joining of the same by the vertical stabilizers produces some effects of a biplane with reductions in induced drag. Additionally, the closed structure may also be made structurally more efficient than a conventional structure having cantilevered lifting surfaces. Although only the preferred embodiment of arrangements for carrying out this invention have been described above, it is not to be construed that the invention is limited to such embodiments. Other modifications may be made by those skilled in the art without departing from the spirit and scope of the invention defined below. No attempt has been made to incorporate any other such modifications or forms in this disclosure in the interests of clarity. | An aircraft structure has an arrangement of aircraft components that provide inherent directional stability for a flight vehicle throughout an angle-of-attack range, even at very high angles-of-attack where conventional means of stabilization are ineffective. Components attached to an aircraft fuselage include a wing, horizontal stabilizers and vertical stabilizers. The wing is mounted forward of the horizontal stabilizers and is carried high on the fuselage. The horizontal stabilizer is mounted toward the rear of the aircraft and is attached near the bottom of the fuselage. The wing and horizontal stabilizers are joined on either side of the aircraft by forwardly sweeping aerodynamically shaped surfaces serving as the vertical stabilizers. The inclination of the vertical stabilizers preferably ranges from 45 degrees (top edge canted outboard) to 90 degrees (panels vertical). Preferably, the surface area of the vertical stabilizers is concentrated aft such that the aerodynamic center of the vertical stabilizers is located behind the center-of-gravity of the aircraft. | 1 |
CROSS-REFERENCE
[0001] This application claims priority from Provisional Patent Application Ser. No. 61/600,068 filed on Feb. 17, 2012.
FIELD OF THE INVENTION
[0002] This invention relates to a masonry tile insert that enables a user to construct a temporary masonry structure, such as a brick wall, fire-pit, barbeque, etc., without permanently mortaring the bricks or blocks together. Because the bricks or blocks are not permanently affixed to one another, the structure can later be deconstructed and the bricks or blocks can be re-used for other purposes. The tile insert device is relatively easy to install and use, inexpensive to manufacture and can be used in conjunction with a variety of masonry products.
BACKGROUND
[0003] Many non-dwelling structures, such as walls, mailboxes, fire pits, barbeques, etc., are constructed of masonry products, such as concrete blocks, bricks and the like, due to the durability and aesthetically pleasing appearance of said products. Traditionally when building with masonry products, the blocks and/or bricks are affixed to one another with mortar, which creates a permanent bond between the various blocks and/or bricks. However, if the resulting structure is no longer needed or desired, it is typically not possible to deconstruct the structure in a manner that would permit the blocks or bricks to be reused in the same fashion. This is true because it is typically not possible to remove or separate the various mortared bricks or blocks without damaging the same or incurring significant expense. Consequently, structures that are no longer needed or desired are typically demolished and the ruble, consisting or broken bricks, block and mortar, is either discarded or used as excavating fill.
[0004] Further, masonry products such as concrete blocks and bricks can be relatively expensive to purchase, and typically require the services of a skilled mason to install, which further increases the cost of using said materials in the building process. Therefore, individuals desiring to construct a temporary structure may forgo masonry products because of their expense, permanency and the forgoing problems associated with dismantling the same, even though the user may prefer the appearance of masonry.
[0005] Another problem associated with the use of permanently affixed masonry products occurs if an individual makes a mistake during the construction process or desires to change the design of the partially completed structure. More specifically, once the masonry products are permanently affixed to one another with mortar, it is typically not possible to undo or change what has already been constructed without incurring significant time and expense. Currently, there is no device or method for securely and removably attaching masonry products to one another without permanently mortaring the same. Additionally, there is also no current device or method for recycling used masonry products in the same manner as their initial use, e.g., in a wall, mailbox, fire pit, barbeque or other aesthetically pleasing structure.
[0006] Consequently, there exists in the art a long-felt need for a tile inert device that can be used to securely and removably attach masonry products to one another without permanently affixing the same. There also exists in the art a long felt need for a tile insert device that permits the associated masonry products to be repeatedly reused and/or recycled without causing damage thereto. Moreover, there is a long felt need for a tile insert device that permits a builder to modify and or change the design of a masonry structure, or correct a construction mistake, during the construction process and without incurring significant time or financial hardship. Finally, there is a long-felt need for a tile insert device that accomplishes all of the forgoing objectives and that is relatively inexpensive to manufacture, aesthetically pleasing, and safe and easy to use.
SUMMARY
[0007] The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed innovation. This summary is not an extensive overview, and it is not intended to identify key/critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
[0008] The subject matter disclosed and claimed herein, in one aspect thereof, is a masonry tile insert device useful for securely and removably attaching masonry products to one another without permanently mortaring the same together. Each of said tile insert devices is preferably comprised of a base with a top surface and a bottom surface; a first insert positioned along said top surface for insertion into an opening in a first masonry product and a second insert positioned along said top surface for insertion into an opening in a second masonry product; and a third insert positioned along said bottom surface for insertion into an opening in a third masonry product and a fourth insert positioned along said bottom surface for insertion into an opening in a fourth masonry product. In a preferred embodiment of the present invention, the tile insert devices could be ornamentally designed to give the appearance of a typical mortar joint.
[0009] The masonry tile inserts of the present invention allow a builder to securely and removably attach various masonry products to one another without permanently mortaring the same together, thereby enabling the builder to change or modify the design of the structure being constructed during the construction process at minimal time and expense. Additionally, when the structure is no longer needed and/or desired, the tile insert devices of the present invention enable the builder to dismantle the structure without damaging the masonry products previously used to build the structure. By preserving the integrity and aesthetics of the original masonry products and the devices, the builder will be able to utilize the same in subsequent projects and therefore realize significant cost savings. Finally, the tile insert devices of the present invention accomplish all of the forgoing objectives and are relatively inexpensive to manufacture, aesthetically pleasing, and safe and easy to use.
[0010] To the accomplishment of the foregoing and related ends, certain illustrative aspects of the disclosed innovation are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles disclosed herein can be employed and is intended to include all such aspects and their equivalents. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a perspective view of a preferred embodiment of the tile insert device of the present invention.
[0012] FIG. 2 illustrates a perspective view of the tile insert device depicted in FIG. 1 about to be installed on a pair of side by side masonry bricks.
[0013] FIG. 3 illustrates a perspective view of a partially constructed structure comprised of a plurality of masonry bricks removably and securely attached to one another via a plurality of tile insert devices.
[0014] FIG. 4 illustrates a perspective view of an alternative embodiment of the tile insert device of the present invention.
DETAILED DESCRIPTION
[0015] The innovation is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding thereof. It may be evident, however, that the innovation can be practiced without these specific details.
[0016] Referring initially to the drawings, FIG. 1 illustrates a perspective view of a preferred embodiment of a tile insert device 100 of the present invention, which is useful in creating a temporary interlocking or interconnecting masonry structure. Device 100 is preferably comprised of a base 110 and more than one insert 140 extending outwardly from said base 110 . Unless otherwise stated, device 100 and its various components are preferably comprised of plastic, though it is contemplated that other suitable materials such as fiberglass, concrete, cement, wood, metal, etc. could also be used provided that the same is generally weather resistant. Base 110 and inserts 140 may be integrally formed, or one or more of inserts 140 may be attached to base 110 by any common means known in the art depending upon the type of materials used. For example, if base 110 and inserts 140 are constructed of plastic or fiberglass, insert 140 may be glued to base 110 .
[0017] As illustrated in FIG. 1 , base 110 is preferably an elongated, plate-like structure comprised of a top 112 , a bottom 116 , a front surface 120 , a back surface (not shown) and sides 128 . In a preferred embodiment of the present invention, the overall length and width of base 110 should be approximately the same as the length and width of the masonry block or brick with which it is being used. For example, a device 100 for use with a standard concrete masonry block may comprise a base 110 that is approximately 15½ to 16 inches in length, as measured between sides 128 , and may have a width of approximately 7½ to 8 inches, as measured between front surface 120 and back surface. By comparison, a device 100 for use with a standard sized masonry brick may comprise a base 110 that is approximately 9 to 10 inches in length, as measured between sides 128 , and may have a width of approximately 3½ to 4¼ inches, as measured between front surface 120 and back surface. Of course, it is contemplated that other size bases 110 could also be used to suit user preference or a particular application.
[0018] The overall thickness of base 110 is preferably equal to that of a standard mortar joint and may be approximately ¼ to ⅝ inches, as measured from top 112 to bottom 116 . In a preferred embodiment of the present invention, front surface 120 and back surface (not shown) will also have the general appearance of a standard mortar joint so as to give the appearance that the various masonry products (i.e., blocks and/or bricks) were permanently mortared together.
[0019] Each of inserts 140 are preferably block like structures that extend outwardly from top 112 and/or bottom 116 , and are comprised of an outward facing surface 144 and sides 148 . In the preferred embodiment of device 100 depicted in FIG. 1 , two inserts 140 are located in spaced apart relationship along top 112 and two additional inserts 140 are located in spaced apart relationship along bottom 116 . Notwithstanding the forgoing, it is also contemplated that device 100 could be comprised of a single insert 140 on each of the top 112 and bottom 116 , or a single insert 140 along the top 112 and two inserts 140 along the bottom 116 , or vice versa. As described more fully below, this alternative embodiment of device 100 is particularly useful for producing the appearance of staggered masonry products and mortar joints.
[0020] It is also contemplated that more than two inserts 140 could be positioned in spaced apart relationship along top 112 and/or bottom 116 , or that insert(s) 140 could be positioned along the bottom 116 but not the top 112 (or vice versa). This type of device 100 is particularly useful along the top row of a structure to not only removably connect the two blocks 220 immediately below device 100 but to also provide a relatively flat cap to the structure being constructed.
[0021] In order to reduce the overall weight and cost of device 100 , and to make the same easier to handle during the installation and/or de-installation process, one or more of inserts 140 may further comprise an opening 150 in outwardly facing surfaces 144 , such as a continuous opening, therein. Openings 150 are also useful for receiving mortar or concrete if, at some point in the future, a user (not shown) decides to make the structure permanent, and desires to core the same with concrete or mortar to add strength to the overall structure.
[0022] Because inserts 140 are inserted into openings 208 formed in a masonry product 200 such as a brick or concrete block, the overall size, shape and spacing of inserts 140 along top 112 and/or bottom 116 should correspond to the particular type of masonry product 200 that device 100 is being used with, as well as the size, shape and spacing of the openings 208 therein. FIG. 2 illustrates a device 100 about to be installed onto a pair of masonry blocks/bricks 200 positioned immediately adjacent to one another. Masonry blocks and bricks are well known in the art, and each of the masonry blocks 200 depicted in FIG. 2 is comprised of a top surface 204 , a front surface 210 , a back surface (not shown), and sides 214 . During the construction process, one of the inserts 140 positioned along the bottom 116 of base 110 is inserted into opening 208 of the first block 200 and the remaining insert 140 positioned along the bottom 116 of base 110 is inserted into opening 208 of the second block 200 , such that device 100 straddles the intersection of the two blocks 200 and interlocks the same. In a similar fashion, additional blocks 200 can now be placed on top of the inserts 140 located along top 112 so that inserts 140 fit within openings 208 to create an interlocking structure.
[0023] FIG. 3 illustrates a perspective view of a partially constructed structure comprised of a plurality of masonry bricks 200 removably and securely attached to one another via a plurality of tile insert devices 100 . More specifically, each of the devices 100 depicted in FIG. 3 are comprised of a base 110 with a top surface 112 and a bottom surface 116 . Two inserts 140 are positioned along the top surface 112 of said base 110 in spaced apart relationship for insertion into corresponding openings 208 in two adjacent bricks 200 positioned above said base 110 , and two inserts 140 are positioned along the bottom surface 116 in spaced apart relationship for insertion into corresponding openings 208 in two adjacent bricks 200 positioned below said base 110 . In this manner, the various bricks 200 and tile insert devices 100 can be removably interlocked together to create a structure without the need for mortar or other more permanent adhesive materials. Further, as previously stated, the front surfaces 120 and back surfaces (not shown) of base 110 may further comprise ornamentation to give the general appearance of a standard mortar joint, which is both aesthetically pleasing and implies that the structure has been permanently constructed.
[0024] FIG. 4 illustrates a perspective view of an alternative embodiment of the tile insert device 100 of the present invention, which is further comprised of at least one panel 124 that extends outwardly from top 112 and/or bottom 116 of base 100 and serves as a vertical spacer between the various masonry blocks 200 being used to build the structure (in place of the otherwise present mortar joint in a permanent structure). Panel 124 may further comprise a front surface 126 and back surface (not shown), each of which may also have the general appearance of a standard mortar joint so as to give the appearance that the various masonry products (i.e., blocks and/or bricks) were permanently mortared together. It is worth noting that the device 100 depicted in FIG. 4 is but one example of how panels 124 can be positioned along base 110 , and that numerous other configurations are contemplated and possible to suit user need and/or preference.
[0025] Having now described the overall structure of tile insert device 100 , its use and usefulness will now be summarized. A user (not shown) desiring to construct a temporary masonry structure, such as a brick or block wall, fire-pit, barbeque, etc., without permanently mortaring the bricks or blocks together could place two blocks 200 adjacent to one another as shown in FIG. 2 , and removably connect said blocks 200 with device 100 . More specifically, the user (not shown) would place device 100 over blocks 200 such that one of the inserts 140 positioned along the bottom 116 of base 110 is inserted into opening 208 of the first block 200 , and the remaining insert 140 positioned along the bottom 116 of base 110 is inserted into opening 208 of the second block 200 so that device 100 straddles the intersection of the two blocks and removably interconnects the same.
[0026] In a similar fashion, additional blocks 200 can now be placed adjacent to the two interconnected blocks and interlocked therewith with additional devices 100 to increase the overall length of the structure. Additionally, to increase the overall height of the structure, additional blocks 200 can be placed on top of the inserts 140 located along top 112 so that inserts 140 fit within openings 208 to create an interlocking structure, as is shown in FIG. 3 . Additional devices 100 can then be placed on top of the second row of blocks 200 , and so on and so forth until the desired structure is complete. Moreover, as previously mentioned, the front surface 120 of base 110 and/or the front surface of panels 124 may further comprise ornamentation or texture that gives the general appearance of a standard mortar joint.
[0027] As an important aspect of the present invention, because the various blocks/bricks 200 and devices 100 are not permanently affixed to one another, a user (not shown) can easily disassemble the structure by removing each layer of blocks and devices when the structure is no longer needed or desired, and the various blocks/bricks 200 and devices 100 can be reused.
[0028] Consequently, the tile insert devices 100 of the present invention allow a builder to securely and removably attach various masonry products, such as concrete blocks, bricks and the like, to one another without having to permanently mortar the same. Because a builder can also relatively easily dismantle a masonry structure constructed with the tile insert devices 100 of the present invention, the builder can change or modify the design of the structure during the construction process at minimal time and expense. Additionally, when the structure is no longer needed and/or desired, the tile insert devices 100 of the present invention further enable the builder to dismantle the structure without damaging the masonry products previously used to build the structure and reuse the same in subsequent projects, therefore resulting in significant time and cost savings. The tile insert devices 100 may also be reused. Finally, the tile insert devices 100 of the present invention accomplish all of the forgoing objectives and are relatively inexpensive to manufacture, aesthetically pleasing, and safe and easy to use.
[0029] Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, a certain illustrated embodiment thereof is shown in the drawings and has been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims.
[0030] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0031] Preferred embodiments of this invention are described herein. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. | A tile inset device for securely and removably attaching two or more masonry products, such as concrete blocks, bricks and the like, to one another without the use or mortar, adhesives or the like. In a preferred embodiment, both the top and bottom portions of the device comprise two or more spaced apart inserts for insertion into an opening in a masonry product. The tile insert devices permit the associated masonry products to be repeatedly reused without causing damage thereto, and permit a builder to modify a partially constructed structure without incurring significant time or financial hardship. The tile insert devices are particularly useful in constructing temporary, non-dwelling, structures, but can also be used in the construction of permanent structures. | 4 |
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for breaking textile fiber bales. The apparatus has at least two rotating breaker aprons or breaker rolls (hereafter designated as breaker members) which are arranged with a close spacing in series in the direction of their rotation (working direction) and which open a plurality of serially arranged textile fiber bales at their underside. The spikes of the breaker members are obliquely supported; the spikes of one breaker member are at an inclination which is oriented oppositely to the spikes of the other breaker member.
In a known bale breaking apparatus a series of textile fiber bales are moved back and forth by serially arranged, slightly spaced conveying means and, at the same time, the bales are opened at their underside. In such an apparatus, the breaker members serve simultaneously as the conveying means and the opening (breaking) means for the fiber bales. The latter therefore rest directly on the conveying means and are moved back and forth during the bale breaking operation. The number of conveying means corresponds approximately to that of the bales resting thereon. With such a simple bale breaking apparatus a high opening efficiency and mixing of the textile fiber bales can be achieved. In such a bale breaker apparatus, there are usually provided two parallel-spaced bale guiding walls which extend in the working direction (that is, in the direction of bale displacement) and which prevent a toppling of the bales in the lateral direction subsequent to the removal of the bale ties (at which time the bales usually become unstable). In the working direction, the bales are adjoined, at both sides, by equally unstable bales so that conditions may be present which could cause a bale to topple in the one or the other working direction.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved apparatus of the above-outlined type in which the danger of bale toppling is eliminated and which is of economic structure.
These objects and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, for receiving the textile fiber bales there is provided a support rack formed of at least two rods extending in the working direction above the rotating breaker members which, in addition to their rotation, travel, as a unit, back and forth underneath the support rack.
In case breaker aprons are used in the apparatus according to the invention as outlined above, the parallel parts of the breaker apron belts are stationary during rotation, similarly to the caterpillars of a tracked vehicle. The belts and the spikes secured to the belts are moved only during the deflection about the end rolls. The obliquely oriented spikes situated on the stationary, parallel portions of the apron belts thus dwell in a stationary manner at the underside of the bale. Only during the semi-circular travel of the belt about the deflecting rolls (end rolls) are parts of the textile fiber bales removed by virtue of the downwardly flipping spikes.
In the apparatus designed according to the invention, the breaker members are, as noted above, movable back and forth and the textile fiber bales remain stationary on the fixedly supported rack during the opening process. During the opening operation, each spike projects through the intermediate space between the support rods and penetrates into the underside of the textile fiber bale, dwells at that location as long as the respective spike is moved downwardly as it moves about the deflecting roll. In this manner, the bales remain stationary and thus cannot topple in the working direction. It is a further advantage of this arrangement that it is sufficient to use only one pair of displaceable breaker members in order to open a plurality of juxtapositioned bales. This results in substantial structural economy. The stationary support rack too, may be manufactured very economically and with simple means. It is an additional advantage of the invention as outlined above that the bales somewhat bulge downwardly between the parallel bars. In this manner, in these locations, the outer face of the bales is somewhat expanded and slightly loosened so that a breaking operation by the spikes is facilitated. Further, it is another substantial advantage that the opening of the bales is effected at their underside. This zone, together with the conveying belt situated below the breaker members may be enclosed at all sides with simple arrangements, so that the closed space may be exposed in a suction stream for removing in a secure manner the dust generated during the bale breaking operation.
For securing the rods of the support rack in a ridge manner, there is advantageously provided a common transverse bar which extends generally horizontally and perpendicularly to the working direction. Expediently, the transverse bar is arranged at a distance above the rods of the support rack so that the spikes of the breaker members may project without obstruction into the intermediate space between the support rods.
The dimensions of the fiber tufts removed from the bales and delivered to the transport belt may be varied by altering the length of the spikes or, without re-tooling, by changing the distance between adjoining breaker members. The output rate of the apparatus may be altered by changing the rotational speed of the breaker members.
The breaker members are supported on a carriage displaceable along the machine frame in the working direction of the breaker members. In order to render the apparatus versatile, the speed of the carriage motion and the rotational speed of the breaker members may be steplessly changed. Expediently, the drives for the breaker members and the carriage may be connected to one another in such a manner that the rotational speed of the breaker members and the speed of the carriage are at least approximately identical. Such a coordination can be effected, for example, by a chain drive or a gear drive. The breaker members and the carriage may, however, each have its own drive motor. In case prior to the complete opening of the bales a bale replacement is to be effected, according to a preferred embodiment of the invention the entire support rack, including the bales, can be laterally shifted. Then, from the other side, another support rack, containing the new bales, may be laterally shifted into an operative position above the breaker members. Expediently, the support rack is formed of a plurality of laterally shiftable partial racks, so that even individual bales may be exchanged in a simple manner. This arrangement saves substantial manual or mechanical input which otherwise would be required for the removal and insertion of the replacement bales.
As the bales rest on the parallel bars of the support rack, the fibers are locally compressed in the zone of contact between rod and bale, so that they have the tendency to resist removal from the bale by the spikes of the breaker members. Accordingly, an advantageous feature of the invention provides that the bale can be easily opened even in the zone of the support bars on which the bale rests. In accordance with this embodiment, on the carriage which supports the breaker members, there are secured stripper elements (knives or teeth) which project into the intermediate space between the support rods. By providing that these stripper elements project into the intermediate space between the support rods, the underside of the textile fiber bales, particularly in the immediate vicinity of the rods, is torn open so that spikes of the breaker members work on already pre-loosened material. Further, above the rods unopened parts of the textile fiber bale may form a bridge which may tend to stiffen. By means of the stripper elements which work immediately adjacent and along the support rods, the bale material is laterally displaced in the zone of the bars, so that the solidified bridges may also be loosened and opened by the spikes of the breaker members. Preferably, the stripper elements are sharpened at their free ends to amplify their pre-loosening effect. For structural reasons, the stripper elements are located expediently in the zone where the breaker members are deflected about the end rolls.
In practice, several stripper elements are arranged next to one another, that is, perpendicularly to the working direction. Expediently, for example, three rows of stripper elements are provided, that is, in front of, between and behind the breaker members as viewed in the working direction. According to a preferred embodiment, the stripping elements arranged behind one another when viewed in the working direction are situated at different sides of the support rods. In this manner, the bale is worked alternatingly from two different sides in the zone of the support rods, whereby the bale material is shifted laterally, thus permitting the loosening of stiffened bridge formations by the spikes of the breaker members.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of a preferred embodiment of the invention.
FIG. 2 is a schematic side elevational view of a detail of FIG. 1 on an enlarged scale.
FIG. 2a is a side elevational view of a detail of FIG. 2, including a distance-adjusting arrangement.
FIG. 3 is a perspective view of detail A of FIG. 2.
FIG. 4 is a schematic cross-sectional front elevational view of a laterally displaceable support rack according to the invention.
FIG. 5 is a schematic side elevational view of the invention, including stripper elements. FIGS. 6 and 7 are respective front and rear elevational views of the structure shown in FIG. 5.
FIG. 8 is a sectional view taken along line VIII--VIII of FIG. 5.
FIG. 9 is a schematic top plan view of a laterally displaceable sectional support rack according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to FIG. 1, there is shown a support rack 1 on which there is positioned a series of ten bales 2. Underneath the support rack 1, there are arranged two breaker aprons 3 and 4, the length of which approximately corresponds to the length of one bale. Underneath the breaker aprons 3 and 4 there are situated two rolls 5 and 6 about which there is trained a rotating transport belt 7. At one terminus of the belt 7, there is arranged a suction funnel 8 leading to a suction conduit 9.
Also turning now to FIG. 2, each breaker apron 3 and 4 is formed of a respective endless belt 10 and 11, the width of which is somewhat greater than the width of each bale. Each breaker apron further has a driven roll 12 and an idling roll 13 about which the respective belt 10 or 11 is trained. The rotational direction of the rolls 12, 13 as well as their rotational speed may be varied. The belt 10 or 11 is provided with a plurality of spikes 14, the length of which is approximately 35 mm. Each spike 14 is at an oblique inclination with respect to the belts 10 and 11. Further, the spikes of the belt 11 have an oblique orientation which is opposite to that of the spikes supported on the belt 11. The distance between adjoining breaker aprons 3 and 4 may be steplessly varied by a relative shift of the breaker aprons 3 and 4 with respect to one another. In this connection reference is made to FIG. 2a which illustrates such a distance-adjusting device for the breaker aprons 3 and 4. Nuts 35 and 36 which are fixedly attached to the breaker aprons 3 and 4, respectively, threadedly engage a common spindle 37. The latter is driven by a motor 38. The nut 35, as well as the spindle zone associated therewith have a matching left-hand thread, while the nut 36 as well as the spindle zone associated therewith have a matching right-hand thread. Thus, dependent upon the direction in which the motor 38 is rotated, the breaker aprons 3 and 4 are moved towards or away from one another. The breaker aprons 3 and 4 are mounted on a carriage 15 which, in turn, is displaceably supported on the frame 16 of the apparatus. The carriage 15 is driven by a chain 19 trained about two sprockets 17 and 18. Into a further chain 20, secured to the frame 16, there project gears 21 and 22 which are rotatably mounted on the carriage 15. The gears 21 and 22 simultaneously drive, through a chain 23, the drive rolls 12 and 13 of the respective breaker aprons 3 and 4. In this manner, the drive of the carriage 15 and the drive of the breaker aprons 3 and 4 are connected to one another so that a positive drive is effected between the traveling movement of the carriage 15 and the rotation of the belts 10 and 11. The entire drive chain arrangement may be driven by a sole motor M, whose speed is preferably steplessly variable and which drives the roll 17 by the intermediary of a chain 17a.
As illustrated in FIG. 3, the support rack 1 is formed of a plurality of parallel-spaced support rods 24 extending in the working direction and attached to a transverse bar 25 which, in turn, extends generally horizontally and perpendicularly to the working direction. The transverse bar 25 is situated above and spaced from the support rods 24 and is itself supported by uprights 26 arranged on either side of the breaker aprons.
After depositing, for example, ten bales 2 on the support rack 1, the two breaker aprons 3 and 4 are driven with identical speed and in the same direction. The spikes 14 project through the spacing between the rods 24 of the support rack 1 (as illustrated in FIG. 3) into the bales 2. Simultaneously, the carriage 15, on which the breaker aprons 3 and 4 are mounted, is driven with the same speed as the breaker aprons 3 and 4. The bales 2 remain stationary on the rods 24 of the support rack 1 and are laterally supported by lateral bale supporting walls W arranged on both sides of the support rack 1 and extending in a vertical orientation, in the working direction. Since the spikes 14 of the breaker apron 3, as they emerge from a bale, move downwardly with a substantially greater speed by virtue of the deflection of the belt 10, they tear, from the bale, small fiber tufts which drop on the transport belt 7. As soon as the leading breaker apron 4 reaches the end of the last bale 2, the drive of the rolls of the carriage 15 and the breaker aprons 3 and 4 is reversed. This may be effected, for example, by a photocell arrangement or by a limit switch. The breaker aprons 3 and 4 move then in the opposite direction underneath the bales 2 lying on the support rack 1, at which time then the spikes 14 of the breaker apron 4 tear, from the underside of the bales 2, fiber tufts which drop on the transport belt 7. When the now leading breaker apron 3 has reached the end of the last bale 2, the drive of the breaker aprons 3 and 4 is again reversed. The fiber tufts received on the transport belt 7 are drawn through the suction funnel 8 into the conduit 9 and are then advanced therefrom to the next processing station. The size of the fiber tufts falling onto the transport belt 7 may be varied by changing the spikes 14 and/or by changing the distance between the breaker aprons 3 and 4. The output rate of the apparatus may be varied by changing the rotational speed of the breaker aprons 3 and 4, for example, by varying the speed of the motor M.
Also turning now to FIG. 4, the support rack 1 shown therein is formed of a transverse bar 25' which extends laterally beyond the width of the breaker aprons 3 as well as eight parallel-spaced support rods 24 which are secured to the transverse bar 25' and which extend in the working direction of the breaker aprons 3 and 4. The transverse bar 25' is attached to uprights 26' on either side of the breaker aprons 3 and 4. The uprights are movable on the floor by means of wheels 27, so that the entire support rack, together with the bales placed thereon, is displaceable horizontally and perpendicularly to the working direction of the breaker aprons 3 and 4. Each bale is supported on four support rods 24 so that a standby bale may be positioned next to the bale being opened and then, when desired, the support rack may be shifted to align the standby bale series with the breaker aprons 3 and 4. Thus, expediently, the width of the support rack is at least twice the width of the breaker aprons 3 and 4 (measured in a horizontal direction perpendicularly to the working direction). In this manner, a rapid bale replacement may take place. By longitudinally sectionally connecting the support racks to one another it is feasible to effect a bale replacement while other bales behind and in front of the moved rack section remain in place. Thus, for this purpose, as seen in FIG. 9, the support rack is formed of a plurality of partial support racks 1". Each partial support rack 1", in turn, is formed of two transverse bars 25" and, for example, eight support rods 24 connected to the two transverse bars 25". The partial support racks 1" are arranged behind one another as viewed in the working direction and are individually displaceable in the lateral direction by rolling them on wheels (not shown in FIG. 9).
Turning now to FIG. 5, at the two ends (as viewed in the working direction) of the breaker members 3 and 4 considered as a unit there are provided, in the zone of deflection, stripper knives 28 and 29 secured to respective holders 30 and 31 which, in turn, are mounted on the carriage 15. Further, between the slat tables of the aprons 3 and 4, there are provided additional knives 32 and 33 supported on a holder 34 also secured to the carriage 15. The holders 30, 31 and 34, the stripper knives 28, 29, 32 and 33 and the breaker aprons 3 and 4 move as a unit with the carriage 15.
FIG. 6 is a front elevational view of the location of deflection of the breaker apron 3. On the holder 30, there are arranged in juxtaposition, for example, five stripper knives 28 immediately adjacent the support rods 24.
FIG. 7 shows a rear elevational view of the locations of deflection of the breaker apron 4. On the holder 31, there are secured in a juxtaposition, for example, four stripper knives 29 immediately adjacent the rods 24.
Turning now to FIG. 8, there is shown the holder 34 which is situated in the intermediate space between the locations of deflection of the breaker aprons 3 and 4. While the stripper knife 32 associated with the breaker apron 3 operates at one side of the associated support rod 24, the stripper knives 33 cooperating with the breaker apron 4 work on the bale at the other side of the associated support rod 24.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. | An apparatus for breaking textile fiber bales includes at least two spiked breaker members rotated in the working direction for opening the bales at their underside; a stationary support rack for receiving thereon a plurality of bales juxtapositioned in the working direction; and an arrangement for moving the breaker members as a unit back and forth in the working direction underneath the support rack for opening the underside of the bales juxtapositioned on the support rack. The latter has a plurality of parallel-spaced support rods extending in the working direction above the breaker members. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application relates to and claims priority from PCT/JP2010/055474 filed Mar. 28, 2010, the entire contents of which are incorporated herein by reference, which in turn claims priority from JP 2009-084334 filed Mar. 31, 2009.
FIGURE SELECTED FOR PUBLICATION
[0002] No Figures
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a hair cosmetic having both the abilities to set and arrange hair (also including the ability to restyle hair). More specifically, the present invention relates to a hair cosmetic that is capable of setting hair based on fixation and restyling the hair, by virtue of a novel polymer contained therein.
[0005] 2. Description of the Related Art
[0006] Hair styling includes two functions: forming hairstyles and keeping the formed hairstyles. The principles on which these two functions are exerted are allegedly fixation and adhesion (Non-Patent Document 1).
[0007] Hair styling based on fixation is to set hair by forming a solid film using a film-forming agent (polymer resin) called a setting agent. For example, conventional hair gels or hair sprays are based mainly on a hair styling mechanism using a setting resin. For example, Patent Document 1 discloses a hair cosmetic mainly comprising a film-forming polymer such as polyvinylpyrrolidone, sodium polyacrylate, or a polyvinylpyrrolidone-polyvinyl acetate copolymer as a setting resin. Patent Document 2 discloses a hair cosmetic comprising a silylated urethane resin as a setting resin, and has reported that this hair cosmetic forms a film having both softness and hardness and has natural textures and a high ability to keep hairstyles.
[0008] However, the hair cosmetics obtained using the resins as described in Patent Documents 1 and 2 disadvantageously fails to restyle hair from a temporarily formed hairstyle due to a hard film formed by the setting resin and loses styling functions when the film is broken. Specifically, a problem of styling agents based on fixation brought about by such a setting resin is the poor ability to arrange hair, though they are excellent in setting hair.
[0009] On the other hand, styling based on adhesion is to allow hairs to adhere to one another by an oily ingredient. Hair liquids comprising an adhesive oily ingredient such as polyalkylene glycol as a main base, hair waxes that utilize the adhesiveness of a solid oil and have been preferred by the youth in recent years, and so on are known as such styling agents. For example, Patent Document 3 discloses a cosmetic for hair that comprises waxes and a spinnable water-soluble polymer and is excellent in restyling hair.
[0010] However, hair styling based on the adhesiveness of such an oily ingredient is characterized by being capable of restyling through fingers or a brush because the oily ingredient retains flowability and adhesiveness on the hair. A problem of this hair styling is that the ability to set hair (ability to keep hairstyles) as in hair cosmetics comprising a setting resin is not obtained, though it is excellent in the so-called ability to arrange hair.
PRIOR ART DOCUMENTS
Non-Patent Documents
[0000]
Non-Patent Document 1: “Development of Advanced Cosmetics II”, ed. by Masato Suzuki, published by CMC Publishing Co., Ltd., 1996, Chapter 10: Functions of Hair-Styling Agents and State-of-the-Art Technology
Patent Documents
[0000]
Patent Document 1: JP-A-2006-213706
Patent Document 2: JP-A-2003-171244
Patent Document 3: JP-A-Hei 10-45546
ASPECTS AND SUMMARY OF THE INVENTION
[0015] A hair cosmetic is provided in which the hair (hair style) can be set due to the adhesiveness thereof and yet which shows an excellent hair-arranging ability (including hair-restyling ability). Specifically disclosed is a hair cosmetic comprising, as a hair-setting resin, an adhesive setting resin which is obtained by combining and polymerizing monomers having specific structures and which shows an appropriate hardness and a high adhesiveness in a step of forming a film. In addition, this hair cosmetic preferably contains at least one component selected from a sugar, a sugar alcohol and an EO/PO derivative. Thus, a hair cosmetic having both a high hair-setting power and a good hair-arranging ability can be obtained.
Problems to be solved by the Invention
[0016] Accordingly, an object of the present invention is to provide a hair cosmetic that is capable of setting hair (hairstyle) based on fixation and is also excellent in the ability to arrange hair (also including the ability to restyle hair).
[0017] The present inventors have conducted diligent studies to attain the object and consequently completed the present invention by finding that a hair cosmetic having both the abilities to set and arrange hair is obtained by formulating, as a setting resin, a novel adhesive setting resin having moderate hardness and high adhesive strength during film formation.
Means for Solving the Problems
[0018] Specifically, the present invention provides a hair cosmetic comprising an adhesive setting resin, alcohol, and water, characterized in that the adhesive setting resin is obtained by polymerizing: at least one monomer represented by the following formula (A) (hereinafter, referred to as a “monomer A”):
[0000]
[0019] wherein R1 represents H or CH 3 ; n represents an integer of 0 to 30; (CH 2 ), contains a branched chain; and R2 represents H, OH, OCH 3 , OCH 2 CH 3 , or phenyl,
[0000] and/or
at least one monomer represented by the following formula (B) (hereinafter, referred to as a “monomer B”):
[0000]
[0020] wherein R3 represents H or CH 3 ; R4 and R5, which may be the same or different, each represent H or (CH 2 ) 1 R′; l represents an integer of 1 to 3; R′ represents H, OH, or —NR″R′″; and R″ and R′″, which may be the same or different, each represent H or a C1-C3 alkyl group, and
[0021] at least one monomer represented by the following formula (C) (hereinafter, referred to as a “monomer C”):
[0000]
[0022] wherein R6 represents H or CH 3 ; p represents an integer of 1 to 100; m represents an integer of 0 to 30; R7 represents H, OH, OCH 3 , OCH 2 CH 3 , or phenyl; and X represents an oxyethylene group (EO), an oxypropylene group (PO), an oxybutylene group (BO), or a glyceryl group, and
[0023] at least one monomer represented by the following formula D (hereinafter, referred to as a “monomer D”):
[0000]
[0000] wherein R8 represents H or CH 3 ; q represents an integer of 1 to 100; and Y represents an oxyethylene group (EO), an oxypropylene group (PO), an oxybutylene group (BO), a linear or branched oxyalkylene group having 5 or more carbon atoms, or a glyceryl group, provided that q represents 1 when Y represents a linear or branched oxyalkylene group having 5 or more carbon atoms.
[0024] It is preferred that the hair cosmetic of the present invention should further comprise at least one selected from sugar, sugar alcohol, and an EO/PO derivative, in addition to the adhesive setting resin.
Effects of the Invention
[0025] A hair cosmetic of the present invention can have both the abilities to set and arrange hair, which are impossible to achieve for conventional setting resins, by formulating therein the novel adhesive setting resin described above.
[0026] Furthermore, the combination of the adhesive setting resin and at least one selected from sugar, sugar alcohol, and an EO/PO derivative can further improve adhesion functions (ability to arrange hair).
[0027] The above, and other aspects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] None
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Modes for Carrying Out the Invention
[0029] A hair cosmetic of the present invention comprises, as an essential ingredient, an adhesive setting resin obtained by polymerizing the monomers A and/or B, and C, and D described above. Specifically, for the adhesive setting resin of the present invention, it is essential to comprise the monomers C and D. The adhesive setting resin of the present invention can comprise any one of the monomers A and B, or both. A resin (polymer) that lacks the monomer C or D produces neither favorable adhesive strength nor the ability to arrange hair (ability to restyle hair).
[0030] It is particularly preferred that the adhesive setting resin used in the present invention should have a structure represented by the following formula (I):
[0000]
[0031] In the formula (I), R1 to R9, n, m, p, and q are as defined in the formulas A to D; a represents a number within the range of 40<a<400; b represents a number within the range of 80≦b<300; c represents a number within the range of 30<c<300; and d represents a number within the range of 0<d<10.
[0032] The percentage by mass of each monomer in the adhesive setting resin (polymer of the formula (I)) that satisfies the conditions described above is approximately as follows: 7.5<A<62.5, 20≦B<45, 7.5<C<60, and 0<D<5.
[0033] The adhesive setting resin of the present invention can be prepared by mixing the monomers A and/or B, and C, and D at an appropriate ratio and polymerizing the mixture through reaction using a standard method, if necessary, in an appropriate solvent. For example, the adhesive setting resin can be obtained by thermally polymerizing the mixture at approximately 80° C. for 8 hours using a polymerization initiator such as 2,2′-azobisisobutyronitrile in ethanol. The obtained polymer can be purified appropriately for use.
[0034] The amount of the adhesive setting resin formulated in the hair cosmetic of the present invention can vary depending on the product form thereof and is generally 0.1 to 30% by mass, preferably 1 to 20% by mass, more preferably 2 to 15% by mass. If the amount is less than 0.1% by mass, the ability to arrange hair may be insufficient. If the adhesive setting resin is formulated in an amount exceeding 30% by mass, the resulting hair cosmetic may make hair bristly.
[0035] The hair cosmetic of the present invention comprises alcohol and water in addition to the adhesive setting resin.
[0036] One or two or more selected from alcohols generally used in cosmetics, such as ethanol, can be selected appropriately and used as the alcohol in the hair cosmetic of the present invention. The amount of the alcohol formulated is not particularly limited and can vary depending on the form of the hair cosmetic. The alcohol is usually formulated in an amount from the lower limit for use as a solvent in the adhesive setting resin to 80% by mass. Moreover, in some times, it is preferred that the amount of the alcohol formulated should be adjusted according to the amount of water formulated, in terms of controlling usability.
[0037] The content of water in the cosmetic of the present invention is usually 5 to 80% by mass, preferably 10 to 70% by mass.
[0038] It is preferred that the hair cosmetic of the present invention should further comprise at least one selected from sugar, sugar alcohol, and an EO/PO derivative. The formulation thereof can further improve the ability to arrange hair.
[0039] Examples of the sugar used in the present invention include monosaccharides and oligosaccharides. Specific examples of the monosaccharides include: triose, for example, D-glycerylaldehyde and dihydroxyacetone; tetrose, for example, D-erythrose, D-erythrulose, and D-threose; pentose, for example, L-arabinose, D-xylose, L-lyxose, D-arabinose, D-ribose, D-ribulose, D-xylulose, and L-xylulose; hexose, for example, D-glucose, D-talose, D-psicose, D-galactose, D-fructose, L-galactose, L-mannose, and D-tagatose; heptose, for example, aldoheptose and heptulose; octose, for example, octulose; deoxy sugar, for example, 2-deoxy-D-ribose, 6-deoxy-L-galactose, and 6-deoxy-L-mannose; amino sugar, for example, D-glucosamine, D-galactosamine, sialic acid, aminouronic acid, and muramic acid; and uronic acid, for example, D-glucuronic acid, D-mannuronic acid, L-guluronic acid, D-galacturonic acid, and L-iduronic acid. Further examples thereof include their derivatives (POE/POP-added, alkyl group-added, cationized, anionized, or silylated derivatives).
[0040] Examples of the oligosaccharides include sucrose, maltose, cellobiose, gentianose, umbelliferose, lactose, planteose, isolychnoses, trehalose, raffinose, lychnoses, umbilicin, stachyose verbascose. Further examples thereof include their derivatives (POE/POP-added, alkyl group-added, cationized, anionized, or silylated derivatives).
[0041] Examples of the sugar alcohol include mannitol, xylitol, erythritol, sorbitol, maltitol, and inositol. Also, their derivatives (POE/POP-added, alkyl group-added, cationized, anionized, or silylated derivatives) may be used.
[0042] The sugar and the sugar alcohol used in the present invention are not limited. Among them, sugar alcohol, particularly, maltitol or sorbitol is most preferable.
[0043] The amount of the sugar and/or the sugar alcohol formulated in the hair cosmetic of the present invention is generally 0.1 to 20% by mass, preferably 1 to 20% by mass, more preferably 3 to 10% by mass. If the amount is less than 0.1% by mass, the effect of improving the ability to arrange hair (ability to restyle hair) may be insufficient. If the sugar and/or the sugar alcohol are formulated in an amount exceeding 30% by mass, the resulting hair cosmetic may make hair sticky.
[0044] The EO/PO derivative used in the present invention is any of compounds that encompass hair-styling oils and polyalkylene glycols shown below.
[0045] The hair-styling oils mean EO/PO adducts of monohydric to tetrahydric alcohols or monovalent to trivalent carboxylic acids. Those commercially available can be used, and examples thereof can include UNILUB 50 MB-168, UNILUB MB-370, BELTAMOL P-700, BELTAMOL DG-25, TRIOL G-40, SAVON D′OR SGP-7, and SAVON D′OR GP-9 (all from NOF CORP.), and ESTEMOL 50 (Nisshin Oil Mills Co., Ltd.).
[0046] The polyalkylene glycols mean polyalkylene glycol, for example, addition polymers of ethylene oxide (EO), propylene oxide (PO), or butylene oxide (BO). Those commercially available can be used, and examples thereof can include: EO addition polymers such as PEG200, PEG300, PEG400, PEG600, PEG1000, PEG1540, PEG2000, PEG4000, PEG6000, PEG11000, and PEG20000 (NOF CORP. or TOHO Chemical Industry Co., Ltd.): and PO addition polymers such as UNIOL D-700, UNIOL D-1000, UNIOL D-1200, and UNIOL D-2000 (all from NOF CORP.).
[0047] The polyalkylene glycols used in the present invention are not limited. Among them, polyethylene glycol is most preferable.
[0048] The amount of the EO/PO derivative formulated in the hair cosmetic of the present invention is generally 0.1 to 20% by mass, preferably 1 to 20% by mass, more preferably 3 to 10% by mass. If the amount is less than 0.1% by mass, the effect of improving the ability to arrange hair (ability to restyle hair) may be insufficient. If the EO/PO derivative is formulated in an amount exceeding 30% by mass, the resulting hair cosmetic may make hair sticky.
[0049] The hair cosmetic of the present invention comprises the novel adhesive setting resin and optionally comprises at least one selected from sugar, sugar alcohol, and an EO/PO derivative. As a result, the hair cosmetic of the present invention exerts the abilities to set and arrange hair. Its form can be provided as various forms such as hair liquids, hair foams, hair mousses, hair sprays, hair mists, hair gels, and hair waxes.
[0050] The hair cosmetic of the present invention may comprise, for example, other ingredients conventionally used in hair cosmetics according to the form thereof, without impairing the effect of the present invention.
EXAMPLES
[0051] Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not intended to be limited to Examples below. Moreover, the amount of each ingredient formulated in Examples, etc., below represents % by mass, unless otherwise specified.
Production Examples and Comparative Production Examples
[0052] Monomers were polymerized according to the composition shown in Table 1 below to prepare adhesive setting resins of the present invention (Production Examples 1 to 6), a monomer C-free resin of Comparative Production Example 1, and a monomer D-free resin of Comparative Production Example 2.
[0053] Specifically, a mixture of monomers mixed in the total amount of 100 parts was prepared in advance. 100 parts of ethanol were added to a 1-L five-neck flask equipped with a dropping funnel containing this mixture, a reflux condenser, a thermometer, a tube for nitrogen substitution, and a stirrer. At the point in time when the ethanol was in a reflux state (approximately 80° C.) by heating under nitrogen flow, 1 part of a polymerization initiator (2,2′-azobisisobutyronitrile) was added into this ethanol, and the mixture was continuously added dropwise thereto for 2 hours. Then, the mixture was left for 8 hours in a reflux state to allow polymerization reaction to proceed. Next, the solvent was distilled off from the solution in the five-neck flask, and ethanol was added such that the solvent content in this solution was adjusted to obtain a hair cosmetic base solution having a 50% solid content.
[0000]
TABLE 1
Pro-
Pro-
Com-
Com-
Chemical
duction
duction
parative
parative
Classi-
structure
Exam-
Production
Exam-
Production
Production
Production
Production
Production
fication
(trade name)
Manufacturer
ple 1
Example 2
ple 3
Example 4
Example 5
Example 6
Example 1
Example 2
A
Butyl acrylate
Idemitsu
40
35
30
15
40
Kosan Co.,
Ltd.
A
Ethyl acrylate
TOAGOSEI
30
30
CO., LTD.
A
Stearyl
NOF CORP.
methacrylate
(BLEMMER
SMA)
A
Hydroxyethyl
OSAKA
15
30
acrylate (HEA)
ORGANIC
CHEMICAL
INDUSTRY
LTD.
A
Methoxyethyl
TOAGOSEI
15
acrylate (Arix C-
CO., LTD.
1)
B
Dimethylacrylamide
KOHJIN
40
30
30
40
35
30
(DMAA)
CHEMICAL
CO., LTD.
B
Dimethylaminopropylacrylamide
TOAGOSEI
20
(DMAPAA)
CO., LTD.
C
Polyoxyethylene
NOF CORP.
55
20
15
15
30
glycol acrylate
(n = 10)
(BLEMMER
AE-400)
C
Polyoxypropylene
NOF CORP.
20
20
30
55
glycol acrylate
(n = 6)
(BLEMMER AP-
400)
D
Polyoxyethylene
Shin-
5
5
5
5
5
glycol diacrylate
Nakamura
(n = 23) (NK
Chemical Co.
ESTER A-1000)
D
Polyoxyethylene
Shin-
5
glycol
Nakamura
dimethacrylate
Chemical Co.
(n = 14) (NK
ESTER 14G)
D
Glycerin
NOF CORP.
5
dimethacrylate
(BLEMMER
NDMA)
Examples and Comparative Examples
[0054] The resins of Production Examples and Comparative Production Examples were used to prepare samples. The samples were evaluated for the ability to set hair, adhesive strength, the ability to arrange hair, the ability to restyle hair, and dryness in hair in use.
[0055] Evaluation methods and evaluation criteria for each property are shown below.
1. Ability to Set Hair
[0056] 0.4 g of the sample was applied to black virgin hair (length: 15 cm, weight: 1 g), then spread over the hair using a comb, and styled such that the hair became straight. Five strands were prepared per sample. These strands were dried at 50° C. for 1 hour and then hung on a graduated board. A length (b) of each bent strand was measured in a thermo-hygrostat with a temperature of 30° C. and a humidity of 90% RH. The ability to set hair (ability to keep hairstyles) was determined according to a formula shown below using a length (a) of the bent strand measured in advance before application of the sample. A numeric value closer to 100% represents the higher ability to set hair and more excellent moisture resistance.
[0000] Ability to keep hairstyles(%)={( a−b )/ a}× 100
<Evaluation Criteria>:
[0057] ⊚: The value was 90% or more.
◯: The value was 70% to less than 90%.
Δ: The value was 50% to less than 70%.
X: The value was less than 50%.
2. Adhesive Strength
[0058] 0.5 g of the sample was applied to one bundle of black virgin hair (length: 20 cm, mass: 2 g). After drying at room temperature, the hair bundle was evaluated for adhesive strength on the hair in a sensory test by 10 female expert panelists.
<Criteria of Evaluation Scores>
[0059] 5: Adhesion was considerably felt.
4: Adhesion was slightly felt.
3: Normal.
[0060] 2: Adhesion was not much felt.
1: Adhesion was not felt.
<Evaluation Criteria>
[0061] ⊚: The total score was 40 or more.
◯: The total score was 30 or more and less than 40.
Δ: The total score was 20 or more and less than 30.
X: The total score was less than 20.
3. Ability to Arrange Hair
[0062] 0.5 g of the sample was applied to one bundle of black virgin hair (length: 20 cm, mass: 2 g). After drying at room temperature, the hair bundle was evaluated for ease of arrangement in a sensory test by 10 female expert panelists.
[0000] <Criteria of evaluation scores>
5: The hair was considerably easily arranged.
4: The hair was slightly easily arranged.
3: Normal.
[0063] 2: The hair was not much easily arranged.
1: The hair was difficult to arrange.
<Evaluation Criteria>
[0064] ⊚: The total score was 40 or more.
◯: The total score was 25 or more and less than 40.
Δ: The total score was 20 or more and less than 25.
X: The total score was less than 20.
4. Ability to Restyle Hair
[0065] 0.5 g of the sample was applied to one bundle of black virgin hair (length: 20 cm, mass: 2 g). After drying at room temperature, the hair bundle was evaluated for ease of restyling (ability to restyle hair) in a sensory test by 10 female expert panelists when the hair was styled immediately after the application and restyled one hour thereafter.
[0000] <Criteria of evaluation scores>
5: Considerable ability to restyle hair.
4: Slight ability to restyle hair.
3: Normal.
[0066] 2: Not much ability to restyle hair.
1: No ability to restyle hair.
<Evaluation Criteria>
[0067] ⊚: The total score was 40 or more.
◯: The total score was 25 or more and less than 40.
Δ: The total score was 20 or more and less than 25.
X: The total score was less than 20.
5. Absence of Dryness
[0068] 0.5 g of the sample was applied to one bundle of black virgin hair (length: 20 cm, mass: 2 g). After drying at room temperature, the hair bundle was evaluated for the absence of dryness during hair styling in a sensory test by 10 female expert panelists.
<Criteria of Evaluation Scores>
5: Hardly dry.
[0069] 4: Not much dry.
3: Normal.
2: Slightly dry.
1: Dry.
<Evaluation Criteria>
[0070] ⊚: The total score was 40 or more.
◯: The total score was 30 or more and less than 40.
Δ: The total score was 20 or more and less than 30.
X: The total score was less than 20.
[0071] Samples were prepared according to the composition listed in Table 2 below. The samples were prepared by adding each polymer to a mixed solution of (1) and (2) and stirring the mixture. Subsequently, the properties of each sample were evaluated according to the criteria described above. The results are also shown in Table 2.
[0000]
TABLE 2
Comparative
Comparative
Comparative
Example 1
Example 2
Example 3
Example 1
Example 2
Example 3
Example 4
Example 5
Example 6
(1) Water
65
60
60
60
60
60
60
60
60
(2) Ethanol
35
35
35
35
35
35
35
35
35
(3)
5
Comparative
Production
Example 1
(4)
5
Comparative
Production
Example 2
(5)
5
Production
Example 1
(6)
5
Production
Example 2
(7)
5
Production
Example 3
(8)
5
Production
Example 4
(9)
5
Production
Example 5
(10)
5
Production
Example 6
Total
100
100
100
100
100
100
100
100
100
Ability to set
X
◯
◯
◯
◯
◯
◯
◯
Δ
hair
Adhesive
X
X
X
◯
◯
◯
◯
◯
◯
strength
Ability to
X
X
X
◯
◯
◯
◯
◯
◯
arrange hair
Ability to
X
X
X
◯
◯
⊚
⊚
◯
◯
restyle hair
Dryness
◯
◯
◯
◯
◯
◯
◯
◯
◯
[0072] As is evident from the results shown in Table 2, the setting resin-free sample (Comparative Example 1) and the samples (Comparative Examples 2 and 3) comprising the monomer C- or D-free resin (Comparative Production Examples 1 and 2) were much inferior in adhesive strength, the ability to arrange hair, and the ability to restyle hair to the samples of Examples 1 to 6 comprising the adhesive setting resin of the present invention.
[0073] Samples were prepared according to the composition listed in Table 3 below, and the properties of each sample were evaluated according to the criteria described above. The results are also shown in Table 3.
[0000]
TABLE 3
Comparative
Example
Example 1
Example 3
Example 7
Example 8
Example 9
10
(1) Water
65
60
64.9
64
55
45
(2) Ethanol
35
35
35
35
35
35
(3) Production Example 3
0
5
0.1
1
10
20
Total
100
100
100
100
100
100
Ability to set hair
X
◯
Δ
◯
◯
◯
Adhesive strength
X
◯
Δ
◯
⊚
⊚
Ability to arrange hair
X
◯
Δ
◯
⊚
◯
Ability to restyle hair
X
⊚
◯
◯
⊚
⊚
Dryness
◯
◯
◯
◯
◯
Δ
[0074] The results shown in Table 3 demonstrated that the ability to arrange hair and the ability to restyle hair were exerted by formulating 0.1% by mass or more of the adhesive setting resin (Production Example 3) of the present invention (Examples 3 and 7 to 10).
[0075] Samples were prepared according to the composition (wherein an EO/PO derivative was formulated in addition to an adhesive setting resin) listed in Table 4 below. The preparation method involved adding (4) to a mixed solution of (1) and (2), stirring the mixture, then adding (3) thereto, and further stirring the mixture. The properties of each sample were evaluated according to the criteria described above. The results are also shown in Table 4.
[0000]
TABLE 4
Example
Example
Example
Example
Example 3
11
12
13
14
(1) Water
60
59
55
50
40
(2) Ethanol
35
35
35
35
35
(3)
5
5
5
5
5
Production
Example 3
(4) PPG-70
1
5
10
20
polyglyceryl-
10
Total
100
100
100
100
100
Ability to set
◯
◯
◯
Δ
Δ
hair
Adhesive
◯
◯
⊚
⊚
⊚
strength
Ability to
◯
◯
◯
◯
◯
arrange hair
Ability to
⊚
⊚
⊚
◯
Δ
restyle hair
Dryness
◯
◯
⊚
⊚
⊚
[0076] The samples of Examples 12 to 14 comprising the EO/PO derivative exhibited excellent properties particularly in terms of adhesive strength, the ability to restyle hair, and the absence of dryness, compared with the EO/PO derivative-free sample of Example 3.
[0077] Samples were prepared according to the composition (wherein sugar alcohol was formulated in addition to an adhesive setting resin) listed in Table 5 below. The preparation method involved adding (4) to (1), stirring the mixture, then adding (2) thereto, stirring the mixture, finally adding (3) thereto, and stirring the mixture. The properties of each sample were evaluated according to the criteria described above. The results are also shown in Table 5.
[0000]
TABLE 5
Example
Example
Example
Example
Example 3
15
16
17
18
(1) Water
60
59
55
50
40
(2) Ethanol
35
35
35
35
35
(3)
5
5
5
5
5
Production
Example 3
(4) maltitol
1
5
10
20
Total
100
100
100
100
100
Ability to set
◯
◯
◯
◯
◯
hair
Adhesive
◯
◯
⊚
⊚
⊚
strength
Ability to
◯
◯
⊚
⊚
⊚
arrange hair
Ability to
⊚
⊚
⊚
⊚
⊚
restyle hair
Dryness
◯
◯
◯
◯
Δ
[0078] The samples of Examples 16 to 18 comprising the sugar alcohol exhibited excellent properties particularly in terms of adhesive strength, the ability to arrange hair, and the ability to restyle hair, compared with the sugar alcohol-free sample of Example 3.
[0079] Samples were prepared according to the composition (wherein two EO/PO derivatives were formulated in addition to an adhesive setting resin) listed in Table 6 below. The preparation method involved adding (4) and (5) to a mixed solution of (1) and (2), stirring the mixture, then adding (3) thereto, and further stirring the mixture. The properties of each sample were evaluated according to the criteria described above. The results are also shown in Table 6.
[0000]
TABLE 6
Example
Example
Example
Example
Example 3
19
20
21
22
(1) Water
60
59
50
40
30
(2) Ethanol
35
35
35
35
35
(3)
5
5
5
5
5
Production
Example 3
(4) PEG-6
0.5
5
10
15
(5) PEG-32
0.5
5
10
15
Total
100
100
100
100
100
Ability to set
◯
◯
◯
◯
◯
hair
Adhesive
◯
◯
⊚
⊚
⊚
strength
Ability to
◯
◯
⊚
⊚
⊚
arrange hair
Ability to
⊚
⊚
⊚
⊚
⊚
restyle hair
Dryness
◯
◯
◯
◯
Δ
[0080] The samples of Examples 20 to 22 comprising the EO/PO derivatives exhibited excellent properties particularly in terms of adhesive strength, the ability to arrange hair, and the ability to restyle hair, compared with the EO/PO derivative-free sample of Example 3.
[0081] The other Examples are shown below.
Example 23
[0082]
[0000]
Liquid styling agent
(1)
ion-exchanged water
balance
(2)
PEG-6
5
(3)
PEG-8
5
(4)
PEG-32
5
(5)
sorbitol
3
(6)
ethanol
35
(7)
fragrance
q.s.
(8)
polymer obtained in Production Example 3
5
(9)
(alkyl acrylate/diacetone acrylamide) copolymer
2.5
(10)
citric acid
q.s.
<Production Process>
[0083] Water-soluble ingredients (2) to (5) were added to water (1) and dissolved by stirring to prepare aqueous parts. Next, (7) was added to (6), and the mixture was stirred for solubilization. Then, (8) and (9) were added thereto, and the mixture was stirred to prepare alcohol parts. The aqueous parts and the alcohol parts were mixed, and (10) was added to the mixture to obtain a liquid styling agent.
Example 24
[0084]
[0000]
Hair liquid
(1)
ethanol
55
(2)
propylene glycol
5
(3)
polyoxyethylene polyoxypropylene pentaerythritol ether
25
(5EO)
(4)
2-ethylhexyl p-methoxycinnamate
0.5
(5)
polymer obtained in Production Example 3
5
(6)
dye
q.s.
(7)
ion-exchanged water
balance
(8)
fragrance
q.s.
<Production Process>
[0085] (2) to (5) were added to (1) and dissolved by well stirring. Next, (8) was added thereto, and the mixture was solubilized to prepare alcohol parts. On the other hand, (6) was dissolved in (7) by stirring, and this solution was used as aqueous parts and mixed with the alcohol parts to obtain a hair liquid.
Example 25
[0086]
[0000]
Hair wax
(1)
candelilla wax
2
(2)
microcrystalline wax
12
(3)
liquid paraffin
3.5
(4)
hydrogenated polyisobutene
3.5
(5)
pentaerythrityl tetraethylhexanoate
3
(6)
PEG-60 glyceryl isostearate
1
(7)
glyceryl stearate
1
(8)
behenyl alcohol
3.3
(9)
stearyl alcohol
0.9
(10)
tocopherol
0.5
(11)
fragrance
q.s.
(12)
ion-exchanged water
balance
(13)
PG
8
(14)
sodium stearoyl methyl taurate
1.2
(15)
silicic acid anhydride
2.5
(16)
TEA
0.4
(17)
polymer obtained in Production Example 3
3
(18)
ethanol
5
<Production Process>
[0087] (1) to (11) were dissolved by stirring at 80 to 90° C., and this solution was used as oil-phase parts. (12) to (14) were dissolved by stirring at 70° C. to 80° C., and this solution was used as aqueous-phase parts. The oil-phase parts were added to the aqueous-phase parts, and the mixture was emulsified using a homo mixer. Then, (15) was added to the emulsion. After neutralization by the addition of (16), (17) and (18) were added thereto, and the mixture was degassed and cooled to obtain a hair wax.
Example 26
[0088]
[0000]
Hair wax
(1)
methylpolysiloxane
2.0
(2)
microcrystalline wax
12.0
(3)
liquid paraffin
3.5
(4)
hydrogenated polyisobutene
3.5
(5)
pentaerythrityl tetra-2-ethylhexanoate
3.0
(6)
PEG-60 glyceryl isostearate
1.0
(7)
glyceryl stearate
1.0
(8)
deodorized cetanol (derived from plant oil)
3.3
(9)
stearyl alcohol
0.9
(10)
tocopherol
0.5
(11)
fragrance
0.1
(12)
ion-exchanged water
balance
(13)
propylene glycol
8.0
(14)
stearyl trimethyl ammonium chloride
1.2
(15)
kaolin
2.5
(16)
triethanolamine
0.4
(17)
polyvinylpyrrolidone-vinyl acetate copolymer
1.8
(18)
polymer obtained in Production Example 3
2.0
(19)
ethanol
5.0
<Production Process>
[0089] (1) to (11) were dissolved by stirring at 85° C. (oil-phase parts). On the other hand, (12) to (14) were dissolved by stirring at 75° C. (aqueous-phase parts). The oil-phase parts were added to the aqueous-phase parts, and the mixture was emulsified. Then, (15) was added to the emulsion. Subsequently, after neutralization by the addition of (16), (17), (18), and (19) were added thereto, and the mixture was degassed and cooled.
Example 27
[0090]
[0000]
Hair wax
(1)
kaolin
1.0
(2)
volatile isoparaffin
5.0
(3)
cetyl octanoate
5.0
(4)
phenylmethylpolysiloxane
0.5
(5)
candelilla wax
3.0
(6)
paraffin wax
8.0
(7)
propylene glycol
5.0
(8)
glyceryl stearate
1.0
(9)
polyoxyethylene glycerin monostearate (5EO)
1.0
(10)
isostearic acid
1.0
(11)
carboxyvinyl polymer
0.4
(12)
potassium hydroxide (adjusted to pH 7.5)
q.s.
(13)
ion-exchanged water
balance
(14)
polymer obtained in Production Example 3
5.0
(15)
sorbitol
3.0
(16)
EDTA-2Na•2H 2 O
0.05
(17)
phenoxyethanol
0.5
(18)
fragrance
q.s.
(19)
highly polymerized polyethylene glycol
0.1
(20)
ethanol
5.0
<Production Process>
[0091] (16), (7), and (15) were added to (13) and dissolved. Then, (11) was added to the solution and uniformly dispersed by stirring. (1) was added thereto and uniformly dispersed using Disper. The mixture was heated to 85° C., and a mixture of (2) to (9) dissolved by stirring at 85° C. in the same way as above was then added thereto and uniformly stirred. Then, (12) was added thereto, and the mixture was emulsified using a homo mixer. (14), (15), and (17) to (20) were sequentially added thereto, and the mixture was cooled to 25° C. to obtain a hair wax.
Example 28
[0092]
[0000]
Hair wax
(1)
talc
1.0
(2)
liquid paraffin
5.0
(3)
pentaerythrityl tetraethylhexanoate
5.0
(4)
polyether-modified methylpolysiloxane
0.5
(5)
carnauba wax
3.0
(6)
polyethylene wax
8.0
(7)
dipropylene glycol
5.0
(8)
polyoxyethylene hydrogenated castor oil (60EO)
2.0
(9)
isostearic acid
1.0
(10)
stearyl alcohol
1.0
(11)
(PEG-240/decyltetradeceth-20/HDI) copolymer
2.0
(12)
triethanolamine (adjusted to pH 7.5)
q.s.
(13)
ion-exchanged water
balance
(14)
polymer obtained in Production Example 3
10.0
(15)
(alkyl acrylate/diacetone acrylamide) copolymer
1.0
(16)
2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium
5.0
betaine
(17)
phenoxyethanol
0.5
(18)
fragrance
q.s.
(19)
highly polymerized sodium polyacrylate
0.1
(20)
ethanol
5.0
<Production Process>
[0093] A hair wax was obtained in the same way as in Example 26.
Example 29
[0094]
[0000]
Hair-styling gel
(1)
carboxyvinyl polymer
0.7
(2)
water dispersion of urethane resin of Production
5.0
Example 2 (resin content: 40% by mass)
(3)
glycerin
2.5
(4)
1,3-butylene glycol
2.5
(5)
polyoxyethylene octyldodecyl ether (20EO)
0.5
(6)
polyether-modified dimethylpolysiloxane
1.0
(7)
sodium hydroxide (adjusted to pH 7.5)
q.s.
(8)
ethanol
20.0
(9)
polyoxyethylene octyldodecyl ether
0.1
(10)
fragrance
0.1
(11)
trisodium edetate
0.03
(12)
ion-exchanged water
balance
(13)
polymer obtained in Production Example 3
5.0
<Production Process>
[0095] (6) was added to (3), (4), (5), and a portion of (12), and the mixture was emulsified using a homo mixer. Subsequently, a portion of the remaining (12) was added to the emulsion to prepare emulsified parts. On the other hand, (1), (2), (7), (8), (9), (10), (11), and (13) were uniformly dissolved in the remaining portion of (12). To this solution, the emulsified parts were added to obtain a hair-styling gel emulsion.
Example 30
[0096]
[0000]
Hair-styling gel
(1)
(PEG-240/decyltetradeceth-20/HDI) copolymer
2.0
(2)
polymer obtained in Production Example 3
1.0
(3)
diglycerin
2.5
(4)
polyethylene glycol 1000
2.5
(5)
polyoxyethylene hydrogenated castor oil (40EO)
0.5
(6)
dimethylpolysiloxane modified with hydroxy at both ends
1.0
(1,000,000 mPa · s)
(7)
sodium hydroxide (adjusted to pH 7.5)
q.s.
(8)
ethanol
20.0
(9)
polyoxyethylene octyldodecyl ether
0.1
(10)
fragrance
0.1
(11)
trisodium edetate
0.03
(12)
ion-exchanged water
balance
(13)
(alkyl acrylate/diacetone acrylamide) copolymer
1.0
<Production Process>
[0097] A hair-styling gel was produced according to Example 29.
Example 31
[0098]
[0000]
Styling mousse
(1)
dimethylpolysiloxane (20 mPa · s)
5.0
(2)
isoparaffin
5.0
(3)
high-molecular-weight polysiloxane
2.0
(4)
amino-modified high-molecular-weight silicone
0.5
(5)
1,3-butylene glycol
3.0
(6)
polyoxyethylene hydrogenated castor oil (40EO)
2.0
(7)
polymer obtained in Production Example 3
10.0
(8)
polyoxyethylene/polyoxypropylene decyl ether
1.0
(12EO•2PO)
(9)
behenyl trimethyl ammonium chloride
0.1
(10)
phenoxyethanol
0.1
(11)
ethanol
8.0
(12)
ion-exchanged water
balance
(13)
fragrance
q.s.
(14)
(octylacrylamide/hydroxypropyl acrylate/butylaminoethyl
1.0
methacrylate) copolymer
<Production Process>
[0099] (3) and (4) were dissolved in (1) and (2) by stirring, and this solution was added to (5), (6), and a portion of (12). The mixture was emulsified using a homo mixer (emulsified parts). On the other hand, (7) was added to the remaining portion of (12) (aqueous-phase parts). (8), (9), (10), (13), and (14) were added to (11) and dissolved by stirring. This solution was added to the aqueous-phase parts, to which the emulsified parts were further added and uniformly mixed to prepare a stock solution. 90 parts of this stock solution were charged into a can for aerosol. The can was valved, and 10 parts of liquefied petroleum gas (LPG) were charged thereto to obtain a styling mousse.
Example 32
[0100]
[0000]
Styling mousse
(1)
dimethylpolysiloxane (6 mPa · s)
5.0
(2)
isoparaffin
5.0
(3)
(PEG/amodimethicone) copolymer
1.0
(4)
1,3-butylene glycol
3.0
(5)
polyoxyethylene hydrogenated castor oil (40EO)
2.0
(6)
polymer obtained in Production Example 3
1.0
(7)
lauric acid diethanolamide
0.2
(8)
stearoxy hydroxypropylamine
0.1
(9)
phenoxyethanol
0.1
(10)
ethanol
8.0
(11)
ion-exchanged water
balance
(12)
fragrance
q.s.
(13)
(octylacrylamide/hydroxypropyl acrylate/butylaminoethyl
0.5
methacrylate) copolymer
<Production Process>
[0101] A styling mousse was produced according to Example 31.
[0102] Unless otherwise defined, all terms (including 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 belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0103] Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes, modifications, and adaptations may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims. | A hair cosmetic is provided in which the hair (hair style) can be set due to the adhesiveness thereof and yet which shows an excellent hair-arranging ability (including hair-restyling ability). Specifically disclosed is a hair cosmetic comprising, as a hair-setting resin, an adhesive setting resin which is obtained by combining and polymerizing monomers having specific structures and which shows an appropriate hardness and a high adhesiveness in a step of forming a film. In addition, this hair cosmetic preferably contains at least one component selected from a sugar, a sugar alcohol and an EO/PO derivative. Thus, a hair cosmetic having both a high hair-setting power and a good hair-arranging ability can be obtained. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of my application Ser. No. 487,155 entitled Compatible AM Stereophonic Transmission System filed July 10, 1974, which issued as U.S. Pat. No. 3,908,090 on Sept. 23, 1975, and my application Ser. No. 487,154 entitled Compatible AM Sterephonic Receivers Involving Sideband Separation at IF Frequency, filed July 10, 1974, which issued as U.S. Pat. No. 3,944,749 on Mar. 16, 1976, the said applications being in turn continuations-in-part of my now abandoned application Ser. No. 251,947 entitled AM Stereophonic Transmission and Reception System, and Methods and Components Utilized Therein, filed May 10, 1972.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to AM stereo receivers designed for reception of a carrier wave having stereo related intelligence appearing in the respective upper sideband and lower sidebands of the transmitted signal, such as disclosed in my prior U.S. Pat. No. 3,218,393, and in my aforesaid copending U.S. Pat. No. 3,908,090. AM stereo receivers according to the invention may incorporate carrier exaltation to reduce signal distortion at low levels of received signal strength and/or inverse amplitude modulation of the carrier and/or quadrature demodulation of the received carrier to derive stereo difference (L -R) signal intelligence and employ inphase detection (e.g. envelope detection or product demodulation) to derive the stero summation (L±R) signal intelligence followed by relative phase shifting and combining of the stereo sum and and difference signals in a manner known per se to produce stereo related (L and R) outputs. Modulation of the carrier wave by an infrasonic frequency (e.g. 15 Hz) is preferably utilized to indicate in the receiver the presence of a stereo modulated signal. Aspects of the invention also relate to specialized receiver circuitry with both stereophonic mode and monophonic mode capabilities and automatic switching therebetween.
2. Description of the Prior Art
Compatible stereophonic AM transmission and reception, involving stereo related upper and lower sidebands, with the difference stereo signal (L-R) intelligence phase modulating the carrier wave and with the summation stereo signal (L+R) intelligence envelope modulating the carrier wave, are disclosed in my U.S. Pat. No. 3,218,393, together with certain forms of receivers for stereophonic reception of a carrier wave so modulated. A further discussion of this compatible AM stereophonic modulation technique appears in my paper entitled "A Stereophonic System For Amplitude Modulated Broadcast Stations", which appears in IEEE Transactions on Broadcasting, Vol. BX-17, No. 2, June 1971, at pages 50-55. To the extent here relevant, the disclosures of this prior patent and this paper are incorporated herein by this reference.
Also known is the so-called "compatible" stereophonic AM system disclosed in Barton U.S. Pat. No. 3,102,167 which in effect utilizes a compromised quadrature modulation technique. To reduce monophonic distortion the Barton system utilizes a relative phase angle between the carrier and sidebands of ± 25° to 30°, with the two channel signals being developed by use of a phase displaced exalted carrier and product demodulation, but without any combining of the demodulated signals.
Also known are stereophonic transmission and reception systems as disclosed in Shoaf U.S. Pat. No. 3,009,151, involving a two-channel FM-AM stereo system wherein stereo related signals are respectively frequency modulated and amplitude modulated on FM band and AM band carrier waves; Colodny U.S. Pat. No. 3,031,529, disclosing a single channel AM stereo system employing synchronous detectors in the receiver portion of the system; Avins U.S. Pat. No. 3,068,475, disclosing a stereo transmission and reception system wherein one stereo related signal is amplitude modulated on a carrier wave and the other stereo related signal is frequency modulated on the same carrier wave; Fink U.S. Pat. No. 3,206,550, disclosing visual display of a stereo presence signal; Hold et al U.S. Pat. No. 3,167,614, disclosing use of an infrasonic tone to indicate stereo signal presence in an AM/PM type transmission system; and Collins U.S. Pat. No. 3,231,672, disclosing an AM stereo system involving linearly added carrier waves at the same frequency but in different phase, with each of the carrier waves amplitude modulated with stereo related signals.
SUMMARY OF THE INVENTION
Features and advantages of the present invention are realized by the presentation of various forms of AM stereophonic receivers for reception of a radiant energy carrier wave modulated with two stereo related signals (L and R), each appearing as an independent, first order single sideband with the carrier essentially being amplitude modulated with the stereo summation (L+R) intelligence and the carrier essentially being phase modulated with the stereo difference (L-R) intelligence, such receivers incorporating use of quadrature demodulation of the phase modulation representing the stereo difference (L-R) intelligence of the received signal, and one or more of the following techniques for optimizing output stereo signal quality:
1. use of inverse amplitude modulation of the carrier, i.e. use of the envelope fundamental (and one or more harmonics thereof as preferred forms) to additionally and inversely modulate the receiver carrier in a manner reducing distortion of the stereo difference signal derived from the additionally modulated carrier;
2. use of carrier enhancement, i.e. an exalted carrier, preferably with phase locked loop or like control of the carrier boost input so that essentially no phase modulation distortion occurs incident to the carrier boost and so that the stereo difference signal derived from the exalted carrier does not contain noise bursts even when the received carrier is fully (i.e. 100%) modulated; and
3. in conjunction with any of the above techniques means detecting and utilizing an infrasonic (e.g. 15 Hertz) tone modulated on the received carrier as an indication of stereo signal presence, such tone being preferably utilized to automatically control receiver output mode.
Further features and advantages of the present invention accrue from the avoidance of use in receivers of the present invention of such circuit components as sideband filters, with the result that circuits are readily adaptable to employment of integrated circuits. 33
Yet another advantage and feature of the AM stereophonic transmission and reception system and method of the present invention is the optional modulation of the carrier with an infrasonic frequency signal to indicate in the receiver stereo signal presence, which signal is utilizable to provide automatic shifting of the reception mode to and from stereophonic and monophonic and/or to provide a carrier tuning indicator.
Other features and advantages of the invention will be apparent from the following description and discussion of certain typical embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a showing, in block diagram form, of a compatible AM stereo receiver designed to receive an AM stereo signal, such as developed in the transmission exciter shown in my aforesaid U.S. Pat. No. 3,908,090, for example, wherein the receiver incorporates enhancement of the phase modulated carrier wave, with utilization of carrier tracking circuitry employing phase locked loop type carrier selection, wherein the receiver employs in-phase detection in the form of an envelope detector to derive the stereo summation (L+R) signal and employs inverse modulation of the phase modulated exalted carrier by either the fundamental of the envelope or by both the fundamental and harmonic components derived from the received carrier envelope, coupled with quadrature demodulation of the phase modulated and inversely amplitude modulated exalted carrier wave to derive a low distortion stereo difference (L-R) signal, the receiver shown in FIG. 1 also including infrasonic tone detection means and electronic switching means responsive thereto to automatically change receiver output mode;
FIG. 2 is a block diagram showing of a modified technique for inverse amplitude modulation of the phase modulated exalted carrier with envelope derived fundamental and second harmonic components to reduce signal distortion, the circuit in this instance including separate amplitude modulators for the envelope fundamental and the envelope second harmonic components;
FIG. 3 is a block diagram showing of a further modified technique for inverse amplitude modulation of the phase modulated exalted carrier wave to further minimize distortion of the stereo difference (L-R) signal output, the technique in this instance involving additional amplitude modulation of the phase modulated exalted carrier with envelope derived second harmonic and third harmonic components as well as a fundamental envelope component;
FIG. 4 is a diagrammatic showing of the spectrum of the received signal with carrier enhanced, as such appears in FIG. 1 at input 26 to the amplitude modulator 28, in the instance of the received signal being a carrier wave fully modulated (phase modulated at 0.5 radian and amplitude modulated at 50%) in one stereo channel (L), and without stereo modulation in the other stereo channel (R);
FIG. 5 is a diagrammatic showing, corresponding to the received signal spectrum shown in FIG. 4, of the amplitude modulator output spectrum as such appears in FIG. 1 at 48, with use of inverse modulation by both the fundamental and the second harmonic of the received carrier envelope;
FIG. 6 is a block diagram showing more detail with respect to a typical carrier track circuit as employed in FIG. 1;
FIG. 7 is a detail showing of a modified portion of the circuit shown in FIG. 6; and
FIG. 8 is a partial block diagram, showing a modification of the receiver shown in FIG. 1, and utilizing product demodulation means rather than envelope detection means as the in-phase detector deriving the L+R signal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates in block diagram form a typical compatible AM stereo receiver according to the present invention. Antenna 10 is connected at line 12 to a conventional RF/IF superheterodyne circuit 14 which produces an intermediate frequency output 16, a portion of which feeds an in-phase detection means such as envelope detector 18, which is suitably a conventional diode detector circuit. IF output 16 is also fed to a carrier track filter circuit 20, such as a phase locked loop means, for carrier selection without inducing phase distortion and which may be conventional per se such as the circuit available by use of Signetics IC No. 562 or which may be in the form of phase locked loop circuit disclosed in my copending application Ser. No. 288,704, filed Sept. 13, 1972, with appropriate modification of such circuit to the extent of addition of phase detector means comparing the carrier tracking circuit input and output and maintaining such in phase, which phasal relationship is necessary in a stereo receiver application such as here presented.
The output 22 of the carrier track circuit 20 is representative of the carrier portion of the received carrier wave and is fed to the summation circuit 24 wherein such output 22 is added to the received carrier wave (at IF), a portion of the output 16 from the RE/IF stages 14 also serving as an input to the summation circuit 24. The combined output 26 from summation circuit 24 suitably, as illustrated in the typical instance in FIG. 4, involves carrier enhancement to the extent that the exalted carrier is about half again larger than the received carrier, i.e. in the specific example illustrated, has a relative voltage of 1.5 volts as compared with a relative carrier level in the receive signal of 0.9415 volt. This phase modulated, exalted carrier wave output is more suitable for demodulation to obtain the phase modulation thereof (after being inversely amplitude modulated in amplitude modulator 28, as more fully discussed hereinafter) in that the enhanced carrier wave cannot have instantaneous zero amplitude, i.e. negative 100% modulation.
The carrier track circuit output 22 is also fed to a phase shift network 30 which displaces the carrier phase by +90°, and the network 30 then feeds the phase shifted carrier output 32 to product demodulator 34. Collectively, the network 30 and demodulator 34 comprise what is known per se as a quadrature demodulator, generally designated at 36. Phase shift network 30 is suitably of a type conventional per se such as shown in "Radio Engineer Handbook", edited by Keith Henny, 5th, Ed. McGraw-Hill Company, New York, New York, 1959, at Chapter 12, and also at pages 16-52. Suitably, also, product demodulator 34 may be of a type conventional per se, such as known with respect to Motorola IC No. MC1596L, for example.
The output 38 of in-phase detector 18 is the amplitude modulation envelope of the received carrier wave, and more particularly is the fundamental of such envelope in that, as known per se, the amplitude modulation or envelope in this type of AM stereo transmission is an essentially distortion-free reproduction of the stereo summation (L+R) intelligence in the sidebands of the received carrier wave. This envelope fundamental output 38 is fed to amplifier 40 and the amplifier output 42 is applied to summation circuit 44 which then provides the audio modulation input 46 for amplitude modulating the phase modulated exalted carrier wave (output 26) in amplitude modulator 28. The output 48 from amplitude modulator 28 is what may be termed an inversely amplitude modulated, phase modulated exalted carrier wave, and is utilized as the second input to product demodulator 34 in the quadrature demodulator circuit 36.
As a significant feature of the present invention, the additional amplitude modulation applied to the carrier wave in amplitude modulator 28 very materially reduces the distortion that would otherwise appear at the output 50 of the quadrature demodulator 36. Using the envelope fundamental (as at output 38) as the only input to amplitude modulator 28 (which mode of operation is realized by leaving manual switch 52 open), the distortion in the demodulated output 50 is reduced to approximately 4%, considered on a voltage comparison basis. If further reduction in harmonic distortion in the stereo difference (L-R) signal is desired or necessary, frequency doubler 54 can be brought into the circuit by closure of switch 52. In this mode of operation, the second harmonic output 56 from frequency doubler 54 is combined in summation circuit 44 with the envelope fundamental (output 42) to provide both fundamental and harmonic envelope components at the audio input 46 to amplitude modulator 28, with consequent further reduction in distortion. The approximate optimum relative levels of the amplitude modulation in amplitude modulator 28 is with the fundamental modulation about 26% and the second harmonic modulation about 8% of the total modulation voltage, on a voltage comparison basis. With these inverse amplitude modulation levels the total second order and greater order distortion appearing at the output 50 from the quadrature demodulator 36 is reduced to about 0.8%, considered on a voltage comparison basis.
Phase shift network means, known per se, are used to combine the stereo difference (L-R) signal output 50 with the envelope fundamental (L+R) output 38, to provide relatively distortion free stereo related signals (L and R), in a manner known per se and described in more detail below.
The receiver system shown in FIG. 1 is similar to the receiver system disclosed in my copending application Ser. No. 487,154 in the sense of its inclusion of means responsive to infrasonic tone modulation of the carrier to indicate stereo signal presence and preferably to automatically establish and maintain the receiver output in stereo mode when such stereo presence signal is present. The automatic shifting of receiver output mode is accomplished through control of electronic switch 58, as also discussed in more detail below. When closed, electronic switch 58 connects the demodulator output 50 to a θ-45° phase shift network 60, the output 62 from which is applied to summation circuit 64 and difference circuit 66. The stereo summation (L+R) signal appearing as the detector output 38 is likewise fed to its associated θ+45° phase shift network 68, the output 70 from which is also fed to sum and difference circuits 64, 66. As indicated, phase shift networks 60 and 68 are a phase difference network pair (θ-45° and θ+45°) which are well known per se in the art and which provide a relatively constant relative phase difference of essentially 90° over an effective audio frequency range while maintaining relatively constant signal amplitudes. For more detail with respect to such networks see, for example, "Normalized Design of 90° Phase-difference Networks" by S.D. Bedrosian, appearing in IRE Transactions of the Professional Group on Circuit Theory, Vol. CP-7, No. 2, at pages 128-136 (June, 1960) and the bibliographical references therein. In general, in this type of output circuitry, the summation circuit 64 favors the left or L channel stereo information and thus the L speaker 68 is driven by the L stereo signal; similarly the difference circuit 66 favors the right or R channel stereo information and drives the R speaker 70. As of course also known per se, stereophonically indistinguishable intelligence in the received signal sidebands (i.e. monophonic intelligence) simply appears as double first order sidebands in the received carrier wave, i.e. appears as conventional double sideband amplitude modulation, and appears as part of the detected envelope and drives both the L speaker 68 and R speaker 70 monophonically.
As shown in my said applications Ser. No. 251,947 U.S. Pat. No. 3,944,749 the electronic switch 58 is controlled by an infrasonic tone (e.g. 15 Hertz) appearing as modulation on the carrier of the received signal. Assuming the infrasonic tone is transmitted by amplitude modulation of the carrier, which is presently believed to be the preferable manner of modulation, the switch 72 is shown in FIG. 1 in its correct position for responding to the infrasonic tone indication of stereo presence in that the infrasonic envelope component appearing in the detector output 38 passes through the switch 72 to bandpass filter 74 which in turn feeds the isolated infrasonic tone output 76 to amplifier 78, the output 80 from which energizes stereo presence indicator lamp 82. The infrasonic tone output 80 is also applied to detector 84 which produces a DC component at output 86 functioning to control the electronic switch 58 by closure of the switch when the stereo infrasonic tone is present (again compare the related portion of the receiver shown in my U.S. Pat. No. 3,944,749. Another mode of operation available is one in which the infrasonic tone indicative of stereo signal presence is phase modulated on the carrier wave (for which see my U.S. Pat. No. 3,908,090. In this operational mode the quadrature demodulator 36 of the receiver shown in FIG. 1 produces as a portion of its output 50 the stereo presence indicating infrasonic tone, and switch 72 is switched to its second position 72' to deliver the demodulator output 50 to the bandpass filter 74 with the filter output 76 controlling the stereo indicator 82 and the electronic switch 58 in the same manner as discussed above. It should be noted that if phase modulation or the like (e.g. quadrature modulation) is used to modulate the infrasonic tone on the carrier, the carrier track circuit 20 must be narrow enough in its output 22 so that it does not maintain track with the infrasonic modulation of the carrier. If it were to maintain such track, the infrasonic tone would be greatly attenuated and the stereo response circuitry (e.g. electronic switch 58) would be disabled. Also shown in FIG. 1 is manual switch 88, which is closed in the event the receiver is to be used solely for stereo reception. In this mode of operation, with switch 88 closed, switch 72, bandpass filter 74, amplifier 78, stereo lamp 82, detector 84 and the electronic switch 58 are unnecessary since switch 88 interconnects directly between the product demodulator output 50 and its associated phase shift network 60.
FIG. 2 is a showing of part of a modified form of AM stereo receiver according to the invention, in which the receiver circuit is as shown in FIG. 1 except for the portion thereof shown in FIG. 2 and discussed below. As shown in FIG. 2, the modified circuit employs two amplitude modulators 28' and 28" , rather than the single modulator 28 of FIG. 1. Amplifier 40, which receives as its input the detector output 38, provides the fundamental component input 42 (as in FIG. 1) for the first amplitude modulator 28'. In this modified circuit the output of the first amplitude modulator 28' is the input 90 for the second amplitude modulator 28" , and an additional audio input 92 to amplitude modulator 28" is derived from frequency doubler 54. The output 94 of the second amplitude modulator 28" then is employed as the input to product demodulator 34. While this arrangement requires a second amplitude modulator 28" , it does provide somewhat less distortion than the circuit arrangement shown in FIG. 1.
FIG. 3 shows a further modified inverse amplitude modulating circuit, which reduces the distortion in the demodulatin stereo difference signal output even below that of the arrangement shown in FIG. 2. In the FIG. 3 circuit, the output 42 from amplifier 40 is fed to frequency doubler 54 (as in FIG. 1) which in turn provides a second harmonic output 56 (also as in FIG. 1) to summation circuit 44'. As will be apparent, the operation of amplifier 40, frequency doubler 54 and the frequency doubler output 56 combined with the fundamental output 42 in summation circuit 44' is the same as in the circuit in FIG. 1 with the switch 52 closed. In FIG. 3, however, there is the additional incorporation in the circuit of a further envelope fundamental component 42 from 3 circuit, 40, which is applied to a frequency tripler 96, the third harmonic output 98 from which is also applied to the summation circuit 44' and there combined with the fundamental component 42 and second harmonic component 56, all in a manner to provide from the summation circuit 44' an output 100 to the amplitude modulator 28 which is still more free of the fourth order sideband components which would otherwise cause distortion in the stereo difference signal output (as at 50 from quadrature demodulator 36 in FIG. 1). Further permutation of harmonic component inputs to the summation circuit (44 or 44') to further minimize stereo difference signal demodulated output distortion, will be apparent to those skilled in the art.
In general, as will be seen from the foregoing discussion of various forms of receiver circuits according to the invention, the inventive concept involved in this type of AM stereo receiver contemplates the reduction of stereo signal distortion by use of component (s) derived from the envelope of the received carrier wave to inversely modulate the total wave (with carrier exaltation or otherwise) thus canceling or tending to cancel undesired spectral components which would otherwise produce distortion when the stereo difference signal is detected by quadrature demodulator means or the like.
FIG. 4 diagrammatically shows the spectrum of the modulated carrier received by the receiver shown in FIG. 1, with carrier enhanced by the carrier track filter circuit, in the representative instance of the received signal being a carrier wave fully modulated in one stereo channel (L) and without modulation in the other stereo channel (R). As will be noted, except for the carrier enhancement, this signal spectrum approximates the signal spectrum shown as the transmitted signal in FIG. 4 of my copending application Ser. No. 487,155. Theoretical analysis shows that demodulation of this signal by quadrature demodulator means and without any additional amplitude modulation (i.e. if the received signal with enhanced carrier output 26 in FIG. 1 were applied directly to the product demodulator 34 without any additional modulation in amplitude modulator 28), provides a stereo difference output signal at output 50 which is characterized by a second harmonic distortion level of about 13% (more accurately 13.05%) and a third harmonic distortion level of about 21/2 % (more accurately 2.33%), on a voltage comparison basis. As will be recognized, and although these amounts of harmonic distortion can be considered tolerable in some system applications, such distortion levels are excessive from the point of view of normal standards for commercial broadcast purposes. However, it is an important feature and advantage of the present invention that such harmonic distortion levels can be readily reduced to commercially acceptable values by selective inverse modulation of the phase modulated carrier wave with the detected envelope wave. If it is desired that such inverse amplitude modulation be applied to achieve near cancellation of the second order distortion, theoretical considerations indicate that the inverse modulation input should reduce the precentage of modulation of the phase modulated carrier wave by a factor of about 26%. Utilizing the approach of inversely modulating the phase modulated carrier wave with the fundamental of the envelope (i.e. with switch 52 open in FIG. 1 and applying the output 42 from amplifier 40 through the summation circuit 44 to the input 46 of amplitude modulator 28), the second harmonic distortion level is reduced to about 0.30% and the third harmonic distortion level becomes about 4.1%. (In a specific instance the level of inverse modulation applied caused a 26.09% reduction in carrier modulation, the resulting second harmonic distortion was 0.30% and the third harmonic distortion was 4.13%, on a voltage comparison basis). Although such amount of third harmonic distortion is tolerable, the substantial level thereof makes it desirable to reduce this harmonic distortion also and this can be done in the receiver shown in FIG. 1 by closure of switch 52 to add a frequency doubled envelope component (i.e. an envelope second harmonic component) to the inverse modulation input 46 to amplitude modulator 28. In a typical specific instance, with an envelope fundamental input (at 42) of about 26% and a second harmonic envelope input (at 56 from frequency doubler 54) of about 8% on a voltage comparison basis, the inversely amplitude modulated, phase modulated exalted carrier wave as such appears at output 48 from the amplitude modulator 28 has a spectral distribution essentially as shown in FIG. 5. (In a specific instance the out-of-phase amplitude modulation fundamental component was at a level of 26.09%, the second harmonic inverse amplitude modulation was at a level of 8.115% with the spectral distribution levels shown in FIG. 5 resulting). By such usage of both fundamental and second harmonic inverse amplitude modulation, in the specific instance cited, the second harmonic distortion level became 0.295%, the third harmonic distortion level became 0.145% and the fourth harmonic distortion level was 0.725%.
As earlier indicated, an alternative technique for inversely amplitude modulating the phase modulated, exalted carrier wave with both fundamental envelope and second harmonic envelope components is shown in FIG. 2. In this instance modulation of the exalter carrier wave by the fundamental occurs in a first amplitude modulator 28' and further modulation with the second harmonic of the envelope occurs in a second amplitude modulator 28" . Analysis has shown that use of separate amplitude modulator stages for the fundamental and second harmonic inversely modulating components results in somewhat less distortion as compared with the use of a single amplitude modulator stage as in FIG. 1.
As a further refinement toward optimization of distortion reduction in the stereo difference signal output 50 in FIG. 1, FIG. 3 shows further modified circitry including a frequency tripler 96 as well as a frequency doubler 54, providing respective envelope harmonic outputs 98 and 56 which are combined with the fundamental envelope output 42 in the summation circuit 44' to further minimize out-of-band distortion.
Reduction of the higher order sideband distortion levels can be further improved by corresponding higher order envelope component inputs, and it will be readily also understood by those skilled in the art to which the invention is addressed that the technique of reducing distortion by inversely modulating the phase modulated carrier with fundamental and harmonic components of the received wave envelope and various relative levels is readily susceptible to many choices of components and component levels to the end sought.
FIG. 6 illustrates in somewhat more detail a typical carrier track filter circuit of the type generally indicated at 20 in FIG. 1. As earlier indicated, this carrier track circuit can, for example, be of a type disclosed in my copending application Ser. No. 288,704. The application of such circuitry in said application Ser. No. 288,704, however, is to a voice type receiver which is not sensitive to phase, whereas proper phasing is an important consideration in a stereo receiver such as presented in FIG. 1 hereof. Because of the phasing requirement, it is necessary to compare the carrier track filter output with the input in a phase detector and use the output of the phase detector to correct the overall phase by control of one of the phase locked loops. Presuming in a typical receiver that the receiver is to follow carrier frequency errors and drift in the range of ±800 Hz, good carrier tracking practice to realize an exalted carrier signal without substantial phase distortion requires that the carrier track circuit be considerably less than ±800 Hz wide as this order of passband would pass many sideband signal components in addition to the desired carrier, particularly since these sideband components in a stereo application are not necessarily symmetrical and the carrier track circuit would follow the resulting phase modulation component of the stereo wave rather than passing only the carrier if the circuit passband is too wide. For this reason, and following the general technique disclosed in my said copending application Ser.No. 288,704, received the carrier track circuitry shown in FIG. 6 applies the carried input 16 first to a first phase locked loop circuit (PLLA), designated 100, which is suitably of a form known per se such as available from Signetics IC No. 562B, and which has a passband of ±800 Hz. The output 102 from the phase locked loop 100 is then applied to a frequency divider circuit 104 wherein the frequency of the carrier is divided by a suitable integer such as 16. This frequency division serves to also divide the frequency error by a like amount (but as a matter of interest does not push the sidebands closer together since sideband spacing is not altered by frequency division of frequency multiplication). With the carrier and any frequency error divided by the selected integer, the frequency reduced output 106 is applied to a second phase locked loop circuit (PLLB) 108 (suitably also a Signetics IC No. 562B) which has a passband of ±50 Hz, in the selected example. This circuit 108 effectively functions as a carrier tracking filter, but is sufficiently narrow not to pass any substantial amount of sideband modulation so that the filtered output 110 consists essentially of only the tracked carrier at the reduced frequency. Then, to isolate the original carrier frequency, the filtered output 110 is applied to frequency multiplier circuit 112 wherein it is multiplied by a suitable integer 16 in the example selected), providing an output 22 which is the tracked carrier at received carrier frequency and which is applied to the summation circuit 24 and to the phase shift network 30 (in FIG. 1).
Considered generally, the carrier track circuit 20 should have a bandwidth capable of tracking the expected frequency drifts in the transmitter and the receiver, and this consideration in some instances may be incompatible with use of phase modulation for the infrasonic tone. For this reason it is considered preferable to amplitude modulate such tone on the carrier, which avoids any problem as to the circuit 20 tracking the infrasonic tone.
As indicated, and because of the frequency division occurring in stage 104 as discussed above, it is necessary to compare the phase of the filter system output 22 with the phase of the received carrier. In FIG. 6 this is done by passing a portion of the output 22 to phase detector 114 (suitably a Motorola IC No. MC4004P) and through a low pass filter (LPF) 116 (typically having a time constant of 15 milliseconds) to provide a control voltage input 118 to the phase locked loop circuit 100. The tracked carrier output 22 is compared in phase with the phase of the input wave 16 in the phase detector 114 and the control voltage output 118 from the phase detector corrects for any major phase errors between such input and output (it being notable that with a frequency division of 16 there are some 16 different phase stable points at which the phase locked loop circuit 108 can lock if it were not for the phase control exerted by the phase detector 114 on the phase locked loop 100). The control exerted by the phase detector 114 on the phase locked loop 100 is made to operate relatively slowly, by action of the low pass filter circuit 116, and principally functions to correct for such major phase errors as may occur when the equipment is turned on or if there is a severe carrier fade making the frequency divider circuit 104 "slip a cog".
FIG. 7 shows in block form a further modified circuit detail providing some simplification of the carrier track circuit shown in FIG. 6. In essence, the phase locked loop 108 and the frequency multiplier stage 112 of the circuit shown in FIG. 6 can be replaced by the circuit shown in FIG. 7, which is known per se. In general, this type of circuit involves applying the frequency divided carrier output 106 to a phase detector 102, the output 122 from which drives a voltage controlled oscillator (VCO) 124 which generates the tracked carrier output 22 at desired frequency. The VCO 124 operates at 16 times the frequency of the input frequency appearing at input 106, and such output 22 is also fed to frequency divider 126, which again divides the frequency exactly 16 times. The output 128 from frequency divider 126 is applied to phase detector 120 wherein the phase of the frequency divided output 128 is compared with the phase of the input signal at 106, with the phase detector 120 producing the output 122 which is utilized in the VCO 124 to maintain the phase of the output 22 in phase with the phase of the input signal. Viewed in another manner, the circuit shown in FIG. 7 functions as an ordinary phase locked loop but with a frequency division of 16 in the feedback path and with the VCO operating at 16 times the input frequency, i.e. to provide accurate, in-phase frequency multiplication.
FIG. 8 is a showing of a part of a further modified form of AM stereo receiver according to the invention, in which the circuit is as shown in FIG. 1 (or FIGS. 2 or 3) except for the portion thereof shown in FIG. 8 and discussed below. Rather than the envelope detector 18 of the FIG. 1 circuit, this modified form utilizes a product demodulator 18' as the in-phase detection means for deriving the L+R signal output 38, with a tracked carrier input 22 also being fed to the demodulator 18'. Although the product demodulator circuit 18' is somewhat more complex than envelope detector 18, it is advantageous from the point of view of improved signal-to-noise characteristics and is presently preferred, particularly under noisy reception conditions.
From the foregoing various further modifications, adaptations and applications of stereo receivers and applications of stereo receivers and components thereof according to the present invention will occur to those skilled in the art to which the invention is addressed, within the scope of the following claims. | Compatible AM stereophonic receivers for reception of a radiant energy carrier wave modulated with two stereo related signals (L and R), each appearing as a respective first order single-sideband. Receivers embodying the invention in general improve an optimize output stereo signal quality by quadrature demodulation of the carrier to derive the stereo difference (L-R) signal, together with in-phase detection of the stereo summation (L+R) signal, the L+R and L-R signals thus derived being placed in phase and combined through sum and difference circuits to obtain the stereo related (L and R) outputs. Demodulation distortion may be minimized by inverse amplitude modulation of the carrier wave with a portion of at least the envelope fundamental (and preferably also one or more harmonics thereof). The carrier wave is preferably enhanced prior to quadrature demodulation and preferably is also modulated with an infrasonic frequency (e.g. 15 Hz) signal indicating stereo signal presence, with such infrasonic modulation either amplitude modulating or phase modulating the carrier wave. Such infrasonic modulation is utilized to automatically switch receiver output mode and to visually indicate stereo signal presence. | 7 |
FIELD OF THE INVENTION
The field of the invention is fracturing and more particularly a method for fracturing in open hole without external zone isolators and more particularly with an ability to seal the annulus without a traditional cementing job.
BACKGROUND OF THE INVENTION
There are two commonly used techniques to fracture in a completion method. FIG. 1 shows a borehole 10 that has a casing string 12 that is cemented 14 in the surrounding annulus 16 . This is normally done through a cementing shoe (not shown) at the lower end of the casing string 12 . In many cases if further drilling is contemplated, the shoe is milled out and further drilling progresses. After the string 12 is cemented and the cement 14 sets a perforating gun (not shown is run in and fired to make perforations 18 that are then fractured with fluid delivered from the surface followed by installation and setting of packer or bridge plug 20 to isolate perforations 18 . After that the process is repeated where the gun perforates followed by fracturing and followed by setting yet another packer or bridge plug above the recently made and fractured perforations. In sequence, perforation and packer/bridge plug pairs 22 , 24 ; 26 , 28 ; 30 , 32 ; and 34 are put in place in the well 10 working from the bottom 36 toward the well surface 38 .
A variation of this scheme is to eliminate the perforation by putting into the casing wall telescoping members that can be selectively extended through the cement before the cement sets to create passages into the formation and to bridge the cemented annulus. The use of extendable members to replace the perforation process is illustrated in U.S. Pat. No. 4,475,729. Once the members are extended, the annulus is cemented and the filtered passages are opened through the extending members so that in this particular case the well can be used in injection service. While the perforating is eliminated with the extendable members the cost of a cementing job plus rig time can be very high and in some locations the logistical complications of the well site can add to the cost.
More recently, external packers that swell in well fluids or that otherwise can be set such as 40 , 42 , 44 , 46 , and 48 in FIG. 2 can be set on the exterior of the string 49 to isolate zones 50 , 52 , 54 , and 56 where there is a valve, typically a sliding sleeve 58 , 60 , 62 and 64 in the respective zones. The string 49 is hung off the casing 66 and is capped at its lower end 67 . Using a variety of known devices for shifting the sleeves, they can be opened in any desired order so that the annular spaces 68 , 70 , 72 and 74 can be isolated between two packers so that pressurized frac fluid can be delivered into the annular space and still direct pressure into the surrounding formation. This method of fracturing involves proper packer placement when making up the string and delays to allow the packers to swell to isolate the zones. There are also potential uncertainties as to whether all the packers have attained a seal so that the developed pressure in the string is reliably going to the intended zone with the pressure delivered into the string 49 at the surface. Some examples of swelling packer are U.S. Pat. Nos. 7,441,596; 7,392,841 and 7,387,158.
In some instances the telescoping members have been combined with surrounding sleeves of a swelling material to better seal the extended ends of the telescoping members to the formation while still leaving open the remainder of the annular space to the formation in a given zone. Some examples of this design are U.S. Pat. Nos. 7,387,165 and 7,422,058. US Publication 2008/0121390 shows a spiral projection that can swell and/or be expanded into wellbore contact and leave passageways in between the projections for delivery of cement.
What is needed and provided by the method of the present invention is a technique to pinpoint the applied frac pressure to the desired formation while dispensing with expensive procedures such as cementing and annulus packers where the formation characteristics are such as that the hole will retain its integrity. The pressure in the string is delivered through extendable conduits that go into the formation. Given banks of conduits are coupled with an isolation device so that only the bank or banks in interest that are to be fractured at any given time are selectively open. The delivered pressure through the extended conduits goes right to the formation and bypasses the annular space in between. Beyond that the string exterior can have a covering of a swelling material such as rubber or a shape memory polymer, either of which can fill the annular gap and replace the traditional and expensive cement job. Those and other features of the present invention will be more readily understood to those skilled in the art from a review of the description of the preferred embodiment and the associated FIGS. 3-10 while understanding that the full scope of the invention is determined by the literal and equivalent scope of the appended claims.
SUMMARY OF THE INVENTION
A fracturing operation is done in open hole. The annular space is spanned by telescoping members that are located behind isolation valves. A given bank of telescoping members can be uncovered and the telescoping members extended to span the annular space and engage the formation in a sealing manner. Pressurized fracturing fluid can be pumped through the telescoped passages and the portion of the desired formation fractured. In a proper formation, cementing is not needed to maintain wellbore integrity. The telescoping members can optionally have screens. Normally, the nature of the formation is such that gravel packing is also not required. A production string can be inserted into the string with the telescoping devices and the formation portions of interest can be produced through the selectively exposed telescoping members. In formations that need annular space isolation, the string in a preferred embodiment can have an external material that grows to seal the annular space in lieu of a traditional cementing operation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prior art system of cementing a casing and sequentially perforating and setting internal packers or bridge plugs to isolate the zones as they are perforated and fractured;
FIG. 2 is another prior art system using external swelling packers in the annular space to isolate zones that are accessible with a sliding sleeve valve;
FIG. 3 shows the method of the present invention using extendable passages into the formation that are selectively accessed with a valve so that the formation can be fractured directly from the string while bypassing the annular open hole space; and
FIG. 4 is a detailed view of a telescoping passage in the extended position;
FIGS. 5 a and 5 b show a telescoping member extended with a sliding sleeve and opened for formation access at the same time;
FIGS. 6 a and 6 b show a running string with extendable devices for extending the telescoping passages to the formation;
FIG. 7 is an embodiment showing the run in position of an assembly with sealing between the telescoping members that can seal the annulus in lieu of cementing;
FIG. 8 is the view of FIG. 7 with the annulus sealed;
FIG. 9 is the view of FIG. 8 with a telescoping passage extended; and
FIG. 10 is the view of FIG. 9 with all the telescoping passages extended.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 3 illustrates one embodiment of the invention where the formation has the characteristics that make annular space isolation between the assemblies 108 optional. The preferred embodiment with annular space isolation is shown in FIGS. 7-10 .
FIG. 3 illustrates an open hole 100 below a casing 102 . A liner 104 is hung off casing 102 using a liner hanger 106 . A fracturing assembly 108 is typical of the others illustrated in the FIG. 3 and those skilled in the art will appreciate that any number of assemblies 108 can be used which are for the most part similar but can be varied to accommodate actuation in a desired sequence as will be explained below. As shown in FIG. 4 each assembly 108 has a closure device that is preferably a sliding sleeve 110 that can be optionally operable with a ball 114 landing on a seat 112 . In one embodiment, the seats and balls that land on them are all different sizes and the sleeves can be closed in a bottom up sequence by first landing smaller balls on smaller seats that are on the lower assemblies 108 and progressively dropping larger balls that will land on different seats to close the valve 110 .
The array of telescoping members 116 selectively covered by a valve 110 can be in any number or array or size as needed in the application for the expected flow rates for fracturing or subsequent production. The telescoping assembly 116 is shown in the retracted position in FIG. 3 while telescoping members 116 ′ are shown in the same FIG. 3 in the extended position against the borehole wall 100 . In the preferred embodiment all the telescoping assemblies 116 are initially obstructed with a plug 118 so that internal pressure in the liner 104 will result in telescoping extension between or among members in each assembly, such as 120 and 122 or however many relatively moving segments are needed depending on the width of the annular gap that has to be crossed to get the leading ends 124 into the formation so that directed pressure will penetrate the formation and not go into the open annulus 126 . The plugs 118 are there to allow all the assemblies 116 to extend in response to the valves 110 at each assembly 116 being open and pressure applied inside the liner 104 . Once all the telescoping assemblies are extended, the plugs 118 in each can be removed. This can be done in many ways but one way is to use plugs that can disappear such as aluminum alloy plugs that will dissolve in an introduced fluid. Each or some of the assemblies can have a screen material 128 in the through passage that forms after extension and after removal of the plug 118 .
The valve 110 associated with each telescoping assembly 116 can also be operated with a sleeve shifter tool in any desired order. Each valve can have a unique profile that can be engaged by a shifting tool on the same or in separate trips to expedite the fracturing with one valve 110 and its associated telescoping array 116 ready for fracturing or more than one valve 110 and telescoping array 116 .
As another alternative for closing the valve 110 articulated ball seats can be used that accept a ball of a given diameter and allow the valve 110 to be operated and the ball to pass after moving the seat where such seat movement configures a another seat in another valve 110 to form to accept another object that has the same diameter as the first dropped object and yet operate a different valve 110 . Other techniques can be used to allow more than one valve to be operated in a single trip in the well. For example an articulated shifting tool can be run in and actuated so that on the way out or into the well it can open or close one or more than one valve either based on unique engagement profiles at each valve, which is preferably a sliding sleeve or even with common shifting profiles using the known location of each valve and shifting tool actuation before reaching a specific valve that needs shifting.
Alternatively rupture discs set to break at different pressure ratings can be used to sequence which telescoping passages will open at a given pressure and in a particular sequence. However, once a rupture disc is broken to open flow through a bank of telescoping passages, those passages cannot be closed again when another set of discs are broken for access to another zone. With sliding sleeves all the available volume and pressure can be directed to a predetermined bank of passages but with rupture discs there is less versatility if particular zones are to be fractured in isolation.
The above method of the present invention allows fracturing in open hole with direction of the fracture fluid into the formation without the need for annular barriers and in a proper formation the fracturing can take place in open hole without cementing the liner. Such a technique in combination with valves at most or all of the telescoping assemblies allows the fracturing to pin done in the needed locations and in the desired order. After fracturing, some or all the valves can be closed to either shut in the whole well where fracturing took place or to selectively open one or more locations for production through the liner and into a production string (not shown). The resulting method described above saves the cost of cementing and the cost of annulus barriers and allows the entire process to the point of the fracturing job to be done in less time than the prior methods such as those described in FIGS. 1 and 2 .
While telescoping assemblies are discussed as the preferred embodiment other designs are envisioned that can effectively span the gap of the surrounding annulus in a manner to engage the formation in a manner that facilitates pressure transmission and reduces pressure or fluid loss into the surrounding annulus. Those skilled in the art will appreciate that the above described method is focused on well consolidated formations where hole collapse is not a significant issue. In other applications, described below, the bottom hole assembly will also feature a swelling material or a shape memory polymer to fill the surrounding annular space 126 described above and left open in the above described embodiment.
One alternative to extending the assemblies 116 hydraulically is to do it mechanically. As shown as 130 in FIG. 5 , the telescoping units are retracted into the casing so as not to extend beyond its outside diameter 132 when installed. When sliding sleeve 134 shifts in FIG. 5 b , such as when ball 138 lands on seat 140 the sliding sleeve 134 has a taper 136 which applies mechanical force onto the telescoping units 130 and extends them to touch the formation. Although a sliding sleeve is preferred, any mechanical devices can be used to mechanically extend the telescoping units. One example, shown in FIGS. 6 a and 6 b , is to use a running string 142 with collapsible pushers 144 to push out the telescoping units as shown in FIGS. 6 a and 6 b . The pushers can be extended with internal pressure or by another means. In this case, a closure device is optional.
Another alternative to pushing out the assemblies 116 with pressure using telescoping components is to incorporate expansion of the liner 104 to get the assemblies to the surrounding formation. This can be with a combination of a telescoping assembly coupled with tubular expansion. The expansion of the liner can be with a swage whose progress drives out the assemblies that can be internal to the liner 104 during run in. Alternatively, the expansion can be done with pressure that not only expands the liner but also extends the assemblies 116 .
Optionally, the leading ends of the outermost telescoping segment 122 can be made hard and sharp such as with carbide or diamond inserts to assist in penetration into the formation as well as sealing against it. The leading end can be castellated or contain other patterns of points to aid in penetration into the formation.
FIG. 7 is identical to FIG. 3 but with one major difference. There are still a plurality of spaced apart fracturing assemblies 108 that have valves 110 telescoping assemblies 116 . In FIGS. 7-10 there are sealing members 200 that have a small dimension for run in as shown in FIG. 7 and that grow in the borehole 202 until they seal it off. The annular spaces 126 shown in FIG. 7 are closed off in FIG. 8 as the sealing members get larger preferably by swelling. The sealing members 200 can swell in the presence of well fluids such as hydrocarbons when they are made of rubber, for example. They can also incorporate a cover that delays the swelling to allow time to get the assembly into position in the wellbore. These covers can be dissolved by well fluids for example. The sealing members 200 can also be formed from a shape memory polymer that in the presence of well fluids or heat artificially added with a heater or by inducing a chemical reaction that is exothermic, for example and all schematically represented by arrow 204 , will swell to seal the annular spaces 126 . In this manner a very expensive cement job can be avoided. In formations where it is beneficial to seal the annular space apart from the access locations to the formation from assemblies 108 , the use of the members 200 is an economical way to seal without the cost and logistical issues involved in a cementing job. This is an even more significant factor in offshore wells where the logistics of conducting a cementing job grow far more complex and therefore expensive.
FIG. 9 shows one set of the telescoping members 116 extended as the fracturing starts in the manner described above, while FIG. 10 illustrates all the telescoping assemblies 116 extended and the annular space 126 sealed by members 200 with breaks around the extended telescoping assemblies 116 .
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: | A fracturing operation is done in open hole. The annular space is spanned by telescoping members that are located behind isolation valves. A given bank of telescoping members can be uncovered and the telescoping members extended to span the annular space and engage the formation in a sealing manner. Pressurized fracturing fluid can be pumped through the telescoped passages and the portion of the desired formation fractured. In a proper formation, cementing is not needed to maintain wellbore integrity. In formations that need annular space isolation, the string in a preferred embodiment can have an external material that grows to seal the annular space in lieu of a traditional cementing operation. | 4 |
FIELD OF THE INVENTION
[0001] The field of the invention generally relates to semiconductor devices and methods for fabricating semiconductor devices, and more particularly relates to insulated gate field effect transistor (IGFET) devices.
BACKGROUND OF THE INVENTION
[0002] Insulated gate field effect transistor (IGFET) devices are widely used in modern electronic applications. Metal-oxide-semiconductor field effect transistor (MOSFET) devices and lateral-(double)-diffused-metal-oxide-semiconductor (LDMOS) devices are well known examples of such IGFET devices. As used herein, the term metal-oxide-semiconductor and the abbreviation MOS are to be interpreted broadly. In particular, it should be understood that they are not limited merely to structures that use “metal” and “oxide”, but may employ any type of conductor, including “metal”, and any type of dielectric, including “oxide”. The term field effect transistor is abbreviated as “FET”. It is known that improved performance of LDMOS devices can be obtained by using reduced surface field (RESURF) structures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
[0004] FIG. 1 is a simplified electrical schematic diagram of an N-channel LDMOS RESURF transistor including a MOSFET and parasitic bipolar transistor associated therewith, according to the prior art;
[0005] FIG. 2 is a simplified electrical schematic diagram of a P-channel LDMOS RESURF transistor including a MOSFET and parasitic bipolar transistors associated therewith;
[0006] FIG. 3 is a simplified cross-section view through a transistor of the type illustrated schematically in FIG. 1 having a floating buried layer underlying the LDMOSFET, according to the prior art;
[0007] FIG. 4 is a simplified electrical schematic diagram showing the junction capacitances between the input electrodes and the underlying buried layer within the N channel devices of FIGS. 1 and 3 , and the P-channel device of FIG. 2 , that impact the breakdown voltage in response to very fast transients, and showing use of a charge pump capacitance to improve device behavior, according to an embodiment of the present invention;
[0008] FIG. 5 is a simplified electrical schematic diagram of the N channel LDMOSFET of FIG. 3 employing a floating buried layer, illustrating how the charge pump capacitance of FIG. 4 is provided to couple the floating buried layer to the drain, to reduce the adverse impact of rapid electrical transients appearing on the source-drain terminals, according to another embodiment of the present invention;
[0009] FIG. 6 is a simplified electrical schematic diagram of a P channel LDMOSFET employing a floating buried layer, illustrating how the charge pump capacitance of FIG. 4 is provided to couple the floating buried layer to the source, to reduce the adverse impact of rapid electrical transients appearing on the source-drain terminals, according to still another embodiment of the present invention;
[0010] FIG. 7 is a simplified cross-section view, analogous to that of FIG. 3 , through an N-channel LDMOSFET showing how the charge pump capacitance of FIG. 5 may be provided, according to a yet further embodiment of the present invention;
[0011] FIG. 8 is a simplified cross-section view, analogous to that of FIG. 7 , through an N-channel LDMOSFET showing how the charge pump capacitance of FIG. 5 may be implemented on a monolithic substrate, according to a still yet further embodiment of the present invention;
[0012] FIG. 9 is a simplified cross-section view, analogous to that of FIG. 7 , through an N-channel LDMOSFET showing how the charge pump capacitance of FIG. 5 may be implemented in a monolithic substrate, according to a yet still further embodiment of the present invention;
[0013] FIG. 10 is a simplified cross-section view, analogous to that of FIG. 9 , through a P-channel LDMOSFET showing how the charge pump capacitance of FIG. 6 may be implemented in a monolithic substrate, according to a still yet another embodiment of the present invention; and
[0014] FIGS. 11-19 are simplified cross-sectional views through the device of FIG. 9 at different stages of manufacture according to additional embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The following detailed description 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 expressed or implied theory presented in the preceding technical field, background, or the following detailed description.
[0016] For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements or regions in the figures may be exaggerated relative to other elements or regions to help improve understanding of embodiments of the invention.
[0017] The terms “first,” “second,” “third,” “fourth” and the like in the description and the claims, if any, may be used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “comprise,” “include,” “have” and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical or non-electrical manner. As used herein the terms “substantial” and “substantially” mean sufficient to accomplish the stated purpose in a practical manner and that minor imperfections, if any, are not significant for the stated purpose.
[0018] As used herein, the term “semiconductor” (abbreviated as “SC”) is intended to include any semiconductor whether single crystal, poly-crystalline or amorphous and to include type IV semiconductors, non-type IV semiconductors, compound semiconductors as well as organic and inorganic semiconductors. Further, the terms “substrate” and “semiconductor substrate” are intended to include single crystal structures, polycrystalline structures, amorphous structures, thin film structures, layered structures as for example and not intended to be limiting, semiconductor-on-insulator (SOI) structures, and combinations thereof The term “semiconductor” is abbreviated as “SC.”
[0019] For convenience of explanation and not intended to be limiting, semiconductor devices and methods of fabrication are described herein for silicon semiconductors, but persons of skill in the art will understand that other semiconductor materials may also be used. Additionally, various device types and/or doped SC regions may be identified as being of N type or P type, but this is merely for convenience of description and not intended to be limiting, and such identification may be replaced by the more general description of being of a “first conductivity type” or a “second, opposite conductivity type” where the first type may be either N or P type and the second type then is either P or N type.
[0020] FIG. 1 is a simplified electrical schematic diagram of N-channel LDMOS RESURF transistor 20 including MOSFET 21 and parasitic bipolar transistor 30 associated therewith, according to the prior art. LDMOS FET 21 comprises N-type source 22 and drain 24 , and conductive gate 25 insulated from and overlying P-type body region 26 . Source 22 is coupled to source terminal 27 and drain 24 is coupled to drain terminal 28 . Parasitic bipolar transistor 30 exists between source 22 (and source terminal 27 ) and drain 24 (and drain terminal 28 ). Parasitic bipolar transistor 30 comprises N-type emitter 32 (e.g., associated with source 22 ), N-type collector 34 (e.g., associated with drain 24 ), P-type base region 36 (e.g., associated with body region 26 ) and internal body resistance 37 . Resistance 37 and emitter 32 are coupled to source terminal 27 . Collector 34 is coupled to drain terminal 28 . U.S. Pat. No. 6,882,023 describes a physical RESURF LDMOS structure that can be represented by the simplified electrical schematic diagram of FIG. 1 including (e.g., N type) drift region and (e.g., P type) RESURF region under which is provided a floating buried layer (e.g., N type) identified in FIG. 1 by the label “FLOATING” 39 , which has no external connection.
[0021] FIG. 2 is a simplified electrical schematic diagram of P-channel LDMOS RESURF transistor 40 with MOSFET 41 , parasitic bipolar transistor 50 associated therewith and further parasitic bipolar device 60 . Further parasitic bipolar device 60 arises because of the presence of an (e.g., N type) floating buried layer underlying MOSFET 41 and parasitic bipolar device 50 in LDMOS transistor 40 . In this respect, LDMOS transistor 40 of FIG. 2 differs from what would be obtained by simply exchanging the N and P regions of LDMOS transistor 20 of FIG. 1 . MOSFET 41 comprises P-type source 42 and drain 44 , and conductive gate 45 insulated from and overlying N-type body region 46 . Source 42 is coupled to source terminal 47 , and drain 44 is coupled to drain terminal 48 . Parasitic bipolar transistor 50 exists between source 42 (and source terminal 47 ) and drain 44 (and drain terminal 48 ). Parasitic bipolar transistor 50 comprises (e.g., P-type) emitter 52 (e.g., associated with source 42 ), (e.g., P-type) collector 54 (e.g., associated with drain 44 ), (e.g., N-type) base region 56 (e.g., associated with body region 46 ) and internal body resistance 57 . Resistance 57 and emitter 42 are coupled to source terminal 47 . Collector 54 is coupled to drain terminal 48 . P and N type RESURF regions and underlying (e.g., N type) floating buried layer are included in transistor 40 , thereby giving rise to further parasitic bipolar transistor 60 . Further parasitic bipolar transistor 60 has (e.g., P type) base 66 coupled to (e.g., P type) collector region 54 of parasitic bipolar 50 and (e.g., P type) drain 44 , (e.g., N type) collector 64 coupled to (e.g., N type) base region 56 of parasitic bipolar transistor 50 , and (e.g., N type) emitter 62 coupled to terminal 59 , identified in FIG. 2 by the label “FLOATING” 59 , which has no external connection.
[0022] The use of a floating buried layer RESURF structures represented by the electrical schematic diagrams of FIGS. 1 and 2 can provide substantially improved breakdown voltages BVdss and relatively low ON resistance Rdson. However, the relatively large area of floating buried layer regions in such devices that lie between the LDMOS device and the substrate may make them susceptible to degradation of the breakdown voltage in the presence of very fast transients, e.g., transient (TR) voltages appearing across source-drain terminals 27 , 28 ; 47 , 48 and/or regions 22 , 24 ; 42 , 44 with rise times of about 100 nanoseconds or less, especially pulses with rise times of about 10 nanoseconds or less. This can result in transient drain-source break-down voltages (BVdss) TR that are substantially less than DC breakdown voltages (BVdss) DC , that is, (BVdss) TR <<(BVdss) DC , where “TR” is understood to refer to transient signals of the type noted above and “DC” is understood to refer to zero frequency or low frequency signals. This situation is undesirable. As an aid to understanding how such (BVdss) TR . degradation can come about, it is useful to consider the physical structure of a typical LDMOSFET device employing a floating buried layer.
[0023] FIG. 3 is a simplified cross-section view through transistor 20 of the type illustrated schematically in FIG. 1 having floating buried layer 72 underlying MOSFET 21 , according to the prior art. Where appropriate, the same reference numbers have been used in FIG. 3 as in FIG. 1 to facilitate correlation between FIGS. 1 and 3 . Transistor 20 of FIG. 3 comprises semiconductor (SC) substrate 70 (e.g., P type) with overlying buried layer 72 (e.g., N type, abbreviated as “NBL”). Above buried layer 72 is overlying further (e.g., P type epi) SC region 74 extending to surface 71 . Located within overlying further region 74 is body region 76 (e.g., P type). Within body region 76 are (e.g., N+) source region 22 and (e.g., P+) body contact region 78 . Also located within overlying SC region 74 are (e.g., N type) drift region 80 and (e.g., P type) RESURF region 82 , which generally underlies drift region 80 . As is well known in the art, to obtain RESURF action, charge balancing should be provided between regions 80 , and 82 and is hereafter presumed in the device of FIG. 3 and subsequent LDMOS devices. Doped (e.g., N+) drain region 24 is provided within drift region 80 extending to surface 71 . N type buried layer 72 is DC isolated from overlying MOSFET 21 by PN junction 92 - 1 between (e.g., N type) buried layer 72 and overlying further (e.g., P type) layer or region 74 . Shallow Trench Isolation (STI) regions 84 are provided extending from surface 71 into SC region 74 in the locations indicated. Sinker region 86 (e.g., N type) extends from beneath STI region 84 through further SC region 74 to make Ohmic contact to buried layer 72 . Conventional gate conductor 25 is provided overlying and insulated from surface 71 between source region 22 and drift region 80 and extending somewhat there-over. When source 22 , gate 25 and drain 24 are appropriately biased, channel 90 forms between source 22 and drain 24 . Conductors are also conventionally provided to couple source region 22 , drain region 24 and gate 25 to their respective terminals 27 , 28 and 29 .
[0024] FIG. 4 shows simplified electrical schematic diagram 68 of internal capacitances associated with transistor 20 of FIG. 3 and transistor 69 of FIGS. 5 (“N channel”) and associated with transistor 40 of FIG. 2 and transistor 69 ′ of FIG. 6 (“P-channel”). Schematic diagram 68 illustrates: (i) how floating buried layer (BL) 72 is capacitively coupled to source terminal 27 (and source region 22 of FIG. 1 ) by junction capacitance 93 and to drain terminal 28 (and to drain region 24 ) by junction capacitances 91 , 92 in N channel device 20 , 69 of FIGS. 1 , 3 and 5 , and (ii) how floating buried layer (BL) 72 is capacitively coupled to drain terminal 48 (and drain region 44 of FIG. 2 ) by junction capacitance 93 ′ and to source terminal 47 (and source region 42 ) by junction capacitances 91 ′, 92 ′ in P channel device 40 , 69 ′ of FIGS. 2 and 6 . Schematic diagram 68 also illustrates how the transient breakdown voltage (BVdss) TR can be improved by use of charge pump capacitance 94 between floating buried layer 72 and drain terminal 28 (or drain 24 ) of N channel device 69 of FIG. 5 , and by use of charge pump capacitance 94 ′ between floating buried layer 72 and source terminal 47 (or source 27 ) of P channel device 69 ′ of FIG. 6 .
[0025] Referring to both FIGS. 3 and 4 , N Channel device capacitance 93 is associated with junction 93 - 1 , capacitance 91 is associated with junction 91 - 1 and capacitance 92 is associated with junction 92 - 1 . (Analogous P channel device capacitance 93 ′, 91 ′ and 92 ′ are associated with junctions 93 - 1 ′, 91 - 1 ′ and 92 - 1 ′ shown in FIG. 10 .) Under DC (e.g., low frequency) conditions, the applied voltage is distributed across these capacitances to floating buried layer (BL) 72 , and the drain-source breakdown voltage BVdss is substantially improved compared to an otherwise similar device without floating BL 72 . However, it has been found that when the applied voltage is in the form of fast transient 95 (e.g., see FIG. 4 ) having the fast rise times noted earlier, the space-charge regions associated with the several junctions between, for example, terminals 27 , 28 (or terminals 48 , 47 ) and BL 72 , represented by capacitances 93 , 91 , 92 (or 93 ′, 91 ′, 92 ′) do not have time to adjust, with the result that the applied voltage is concentrated across a smaller region of the semiconductor (SC) thereby increasing the local electric field so that premature breakdown can occur at voltages (BVdss) TR much lower than (BVdss) DC observed with a substantially DC signal, so that (BVdss) TR <<(BVdss) DC .
[0026] It has further been determined that this condition can be avoided by providing a circuit path by which buried layer 72 can be charge pumped, so that its voltage can also rise rapidly in response to fast transient 95 , thereby preventing the localized electric field from rising above that necessary to induce avalanche and premature breakdown. This is accomplished by providing shunt capacitance 94 , 94 ′ between the appropriate source or drain terminal (or source or drain region) and buried layer 72 . In the N channel device (see also FIG. 5 ), charge pump capacitance 94 is provided between drain terminal 28 (or drain region 24 ) and BL 72 and in the P channel device (see also FIG. 6 ), charge pump capacitance 94 ′ is provided between source terminal 47 (or source region 42 ) and BL 72 .
[0027] Rapid rise time pulses can be readily obtained for test purposes using transmission lines. Such transmission line pulse (TLP) tests are well known in the art. It is found that providing shunt capacitance 94 , 94 ′ improves the transient breakdown voltage so that it equals or exceeds the DC breakdown voltage. This is a much desired result and a significant improvement in the art. The desired magnitude of charge pump capacitance 94 , 94 ′ is discussed later.
[0028] FIG. 5 shows a simplified electrical schematic diagram of N-channel LDMOS RESURF transistor 69 including MOSFET 63 , parasitic bipolar transistor 30 associated therewith and further capacitance 94 , according to another embodiment of the present invention. The same reference numbers are used in FIG. 5 as in FIG. 1 to refer to analogous regions or elements, and reference should be had to the discussion of FIG. 1 for further details. Further capacitance 94 is coupled in FIG. 5 from lead 38 of the floating buried layer in FIG. 1 (identified as “FLOATING 39 ” in FIG. 1 ) to drain terminal 28 so that a rapidly rising pulse applied to terminal 28 can pump charge onto floating BL 72 (see also FIGS. 3-4 ), thereby reducing the peak electric field that must be sustained within the SC of LDMOSFET 69 . Reference number 69 is also intended to refer collectively to specific embodiments 69 - 1 , 69 - 2 , 69 - 3 described later.
[0029] FIG. 6 shows a simplified electrical schematic diagram of P-channel LDMOS RESURF transistor 69 ′ including MOSFET 65 , parasitic bipolar transistor 50 associated therewith, additional parasitic device 60 as noted in connection with FIG. 2 and further capacitance 94 ′, according to still another embodiment of the present invention. The same reference numbers are used in FIG. 6 as in FIG. 2 to refer to analogous regions and elements, and reference should be had to the discussion of FIG. 2 for further details. Further capacitance 94 ′ is coupled in FIG. 6 from emitter 64 of further parasitic transistor 60 associated with the floating buried layer (identified as “FLOATING 59 ” in FIG. 2 ) to source terminal 47 so that a rapidly rising pulse applied to terminal 47 can pump charge onto floating BL 72 (see FIGS. 3-4 ), thereby reducing the peak electric field that must be sustained within the SC of LDMOSFET 69 ′. Reference number 69 ′ is also intended to refer collectively to specific embodiments 69 ′- 1 , 69 ′- 2 , 69 ′- 3 described later.
[0030] FIG. 7 is a simplified cross-sectional view, analogous to that of FIG. 3 , through N-channel LDMOSFET 69 - 1 showing how charge pump capacitance 94 of FIG. 5 may be provided as external capacitance 94 - 1 , according to a yet further embodiment of the present invention. For convenience of explanation and not intended to be limiting, in FIG. 7 and following, illustrative N and P conductivity types are included in the description and the drawings with the various reference numbers by way of example and not limitation. Persons of skill in the art will understand that such conductivity types may be interchanged in other embodiments or referred to as of a first conductivity type, which may be either N or P, and of a second opposite conductivity type which is then either P or N. The same reference numbers are used in FIG. 7 as in FIG. 3 for analogous regions and reference should be had to the discussion of FIG. 3 for further details. Device 69 - 1 of FIG. 7 differs from device 20 of FIG. 3 in that (e.g., N+) contact region 87 is provided to sinker region 86 and external capacitance 94 - 1 is coupled between drain terminal 28 (or drain region 24 ) and contact region 87 to sinker region 86 , which is in turn coupled to buried layer (BL) 72 . Thus, a charge pump path to BL 72 is provided via capacitance 94 - 1 . The use of capacitance 94 - 1 means that BL 72 can continue to be floating for DC and slow AC purposes, so that the advantages of a floating RESURF BL are preserved and there is no adverse affect on the DC breakdown voltage (BVdss) DC or series-ON resistance, while the transient breakdown voltage (BVdss) TR is substantially increased.
[0031] FIG. 8 is a simplified cross-section view, analogous to that of FIG. 7 , through N-channel LDMOSFET 69 - 2 showing how charge pump capacitance 94 of FIG. 5 may be implemented on a monolithic substrate as capacitance 94 - 2 , according to a still yet further embodiment of the present invention. Device 69 - 2 of FIG. 8 differs from device 20 of FIG. 3 in that (e.g., N+) contact region 87 is provided to sinker region 86 and monolithic capacitance 94 - 2 formed on surface 71 of substrate 70 is coupled between drain terminal 28 (or drain region 24 ) and contact region 87 to sinker region 86 , which is in turn coupled to buried layer (BL) 72 . Capacitance 94 - 2 comprises: (i) lower electrically conductive electrode (e.g., metal or metal-SC alloy, etc.) 96 desirably making Ohmic connection to contact 87 to sinker region 86 , (ii) interlayer dielectric 97 of relatively low loss insulator, (e.g., silicon oxide) overlying lower conductor 96 , and (iii) upper electrically conductive electrode (e.g., metal or metal-SC alloy, etc.) 97 which is in turn coupled to drain terminal 28 (or drain region 24 ). Thus, a charge pump path is provided to BL 72 via capacitance 94 - 2 . The use of capacitance 94 - 2 means that BL 72 can continue to be floating for DC and slow AC purposes, so that the advantages of a floating RESURF BL are preserved and there is no adverse affect on the DC breakdown voltage (BVdss) DC or series-ON resistance, while the transient breakdown voltage (BVdss) TR is substantially increased.
[0032] FIG. 9 is a simplified cross-section view, analogous to that of FIG. 7 , through N-channel LDMOSFET 69 - 3 showing how supplementary charge pump capacitance 94 of FIG. 5 may be implemented by capacitance 94 - 3 within monolithic substrate 70 , according to a yet still further embodiment of the present invention. Device 69 - 3 of FIG. 9 differs from device 20 of FIG. 3 in that: (i) deep lateral dielectric isolation wall 100 is provided, in this example, adjacent sinker region 86 and extending from surface 71 (or from STI region 84 ) through SC region 74 and BL region 72 into underlying portion 701 of substrate 70 , (ii) further sinker region 88 is provided extending from surface 71 through region 74 to further (e.g., N type) region 722 to make Ohmic contact thereto, and (iii) (e.g., N+) contact region 89 is provided to further sinker region 88 . STI regions 84 may be omitted in other embodiments. Contact region 89 is electrically coupled to drain terminal 28 (or drain region 24 ). Further sinker region 88 and underlying region 722 may be a single doped region or separately formed, ohmically coupled doped regions of the same conductivity type. Either arrangement is useful.
[0033] Capacitance 94 - 3 is formed by relatively deep dielectric isolation wall 100 , which DC isolates sinker region 86 and BL 72 from sinker region 88 and doped region 722 . Dielectric isolation wall 100 has lateral thickness 101 and vertical extent 102 between substrate 70 and STI region 84 , and functions as the dielectric layer of capacitance 94 - 3 between the opposed conductors formed, on the left, by sinker 88 and doped region 722 and, on the right, by sinker 86 and BL 72 . Silicon dioxide is a non-limiting example of a suitable dielectric material for capacitance 94 - 3 , but other substantially insulating materials may also be used. Means and methods for providing such dielectric isolation walls are well known in the art, and any convenient means that fulfills the desired characteristics described below may be used. In some embodiments, dielectric isolation wall 100 may comprise a sandwich of dielectric material (e.g., silicon oxide) with a polycrystalline SC (e.g., polysilicon) or other conductive inclusion 103 substantially in the center of the dielectric making up isolation wall 100 . When centrally located conductive inclusion 103 is floating, its presence does no harm. Lateral thickness 101 of isolation wall 100 is desirably in the range of about 0.5 to 2.0 micrometers, more conveniently in the range of about 1.0 to 2.0 micrometers and preferably about 1.5 micrometers, although larger or smaller values can also be used. Vertical height 102 of isolation wall 100 approximately from substrate region 701 to the top of sinker 86 is desirably in the range of about 3 to 10 micrometers, more conveniently in the range of about 5 to 9 micrometers and preferably about 8 micrometers, although larger or smaller values can also be used.
[0034] The effectiveness of charge pumping into BL 72 using capacitance 94 - 3 depends upon the magnitude of capacitance 94 - 3 . Persons of skill in the art will understand based on the description herein, that capacitance 94 - 3 may be increased by decreasing thickness (X) 101 , increasing vertical height (Y) 102 and/or increasing the plan view perimeters (Z) of isolation wall 100 forming capacitance 94 - 3 . Stated another way, capacitance C 94-3 =f((Y)*(Z)/(X)), and any or all of these parameters may be adjusted to obtain the desired magnitude of capacitance. The use of capacitance 94 - 3 means that BL 72 can continue to be floating for DC and slow AC purposes, so that the advantages of a floating RESURF BL are preserved and there is no adverse affect on the DC breakdown voltage (BVdss) DC or series-ON resistance Rdson while the transient breakdown voltage (BVdss) TR is substantially increased. The arrangement of FIG. 9 has the further advantage that it uses chip area that would otherwise be substantially occupied by a lateral isolation wall and so has the least adverse impact on die per wafer and manufacturing cost. The arrangement of FIG. 9 is a significant and valuable advance in the art and is preferred.
[0035] FIG. 10 is a simplified cross-section view, corresponding to that of FIG. 6 and analogous to that of FIG. 9 , through P-channel LDMOSFET 69 ′- 3 showing how supplementary capacitance 94 ′ of FIG. 6 may be implemented by capacitance 94 ′- 3 within monolithic substrate 70 , according to a still yet further embodiment of the present invention. Device 69 ′- 3 of FIG. 10 comprises semiconductor (SC) substrate 70 (e.g., P type) with overlying buried layer 72 (e.g., N type, abbreviated as “NBL” or “BL 72 ”). Above buried layer 72 is further overlying (e.g., P type epi) SC region 74 extending to surface 71 . Located within overlying region 74 is (e.g., N type) body region 154 . Within body region 154 are (e.g., P+) source region 42 and (e.g., N+) body contact region 46 . Also located within overlying SC region 74 is (e.g., P type) RESURF region 156 , which generally underlies body region 154 . Also located in further SC region 74 is (e.g., P type) drift region 148 . Doped (e.g., P+) drain region 44 is provided within drift region 148 extending to surface 71 . Shallow Trench Isolation (STI) regions 84 are desirably provided extending from surface 71 into SC region 74 in the locations indicated. STI regions 84 may be omitted in other embodiments.
[0036] Sinker region 86 (e.g., N type) extends from beneath STI region 84 through further SC region 74 to make Ohmic contact to buried layer 72 . Conventional gate conductor 45 is provided overlying and insulated from surface 71 between source region 42 and drift region 148 and extending somewhat there-over. Conductors are conventionally provided to couple source region 42 , drain region 44 and gate 45 to their respective terminals 47 , 48 and 49 . When source 42 , gate 45 and drain 44 are appropriately biased, channel 90 ′ forms between source 42 and drain 44 . Device 69 ′- 3 has: (i) relatively deep lateral dielectric isolation wall 100 , in this example, adjacent sinker region 86 and extending from surface 71 (or from STI region 84 ) through SC region 74 and BL region 72 into underlying portion 701 of substrate 70 , (ii) further sinker region 88 is provided extending from surface 71 through region 74 to further (e.g., N type) region 722 to make Ohmic contact thereto, and (iii) (e.g., N+) contact region 89 is provided to further sinker region 88 . Contact region 89 is electrically coupled to source terminal 47 (or source region 42 ). Further sinker region 88 and underlying region 722 may be a single doped region or may be separately formed, ohmically coupled doped regions of the same conductivity type. Either arrangement is useful.
[0037] Capacitance 94 ′- 3 is formed by dielectric isolation wall 100 , which DC isolates sinker region 86 and BL 72 from sinker region 88 and doped region 722 . The discussion of dielectric isolation wall 100 in connection with FIG. 9 should be referred to for further details. The use of capacitance 94 ′- 3 means that BL 72 can continue to be floating for DC and slow AC purposes, so that the advantages of a floating RESURF BL are preserved and there is no adverse affect on the DC breakdown voltage (BVdss) DC or series-ON resistance Rdson while the transient breakdown voltage (BVdss) TR is substantially increased. The arrangement of FIG. 10 has the further advantage in that it uses chip area that would otherwise be substantially occupied by a lateral isolation wall and so has the least adverse impact on die per wafer and manufacturing cost. The arrangement of FIG. 10 is a significant and valuable advance in the art and is preferred.
[0038] Persons of skill in the art will understand based on the description herein, that charge pump capacitance 94 ′- 3 of P channel device 69 ′- 3 of FIG. 10 employing dielectric trench isolation wall 100 between sinkers 88 and 86 may be replaced by charge pump capacitances 94 ′- 1 corresponding to capacitance 94 - 1 of N channel device 69 - 1 of FIG. 7 or by charge pump capacitances 94 ′- 2 corresponding to capacitance 94 - 2 of N channel device 69 - 2 of FIG. 8 . Any of these P channel device arrangements is useful and a significant advance in the art.
[0039] Further, with respect to the embodiments of FIGS. 7-10 , capacitances 94 - 1 , 94 - 2 , 94 - 3 for N channel devices, and equivalent capacitances 94 ′- 1 , 94 ′- 2 , 94 ′- 3 for P channel devices, should be large enough so that, usefully at least 5% of the voltage of fast transient 95 is coupled from terminals 27 , 28 (or 47 , 48 ) to buried layer 72 , more conveniently at least about 10% of fast transient voltage 95 is coupled from terminals 27 , 28 (or 47 , 48 ) to buried layer 72 , and preferably at least about 20% of fast transient voltage 95 is coupled from terminals 27 , 28 (or 47 , 48 ) to buried layer 72 , but other values may also be used. In the examples of N channel and P channel devices described above, both use N type buried layers, and the charge pump capacitance 94 , 94 ′ is coupled to the high side terminal receiving the fast transient, for example, drain 24 (or drain terminal 28 ) of N channel device 69 , or source 42 (or source terminal 47 ) of P channel device 69 ′.
[0040] FIGS. 11-19 are simplified cross-sectional views through device 69 - 3 of FIG. 9 at different stages 211 - 219 of manufacture showing structures 311 - 319 , according to additional embodiments of the present invention. Persons of skill in the art will understand that the manufacturing sequence illustrated hereafter can generally also be used to form those devices illustrated in cross-sections in FIGS. 7-10 . Modifications needed to provide regions of somewhat different lateral extent, thickness and/or doping, if needed, are within the capabilities of those of skill in the art.
[0041] Referring now to manufacturing stage 211 of FIG. 11 , semiconductor (SC) containing substrate 70 is provided. Buried layer 72 of thickness 721 is formed in or on substrate 70 , for example by ion implantation, but other doping means well known in the art may also be used. In preferred embodiments, at least the upper portion of substrate 70 is P type with doping density usefully in the range of about 1 E 15 to 1 E 18 cm -3 , more conveniently in the range of about 1E15 to 1E16 cm -3 and preferably about 2E15 cm -3 , although higher and lower values can also be used as well as other doping types. Boron is a suitable dopant for substrate 70 , but other dopants may also be used. Buried layer 72 is desirably N type with doping density usefully in the range of about 5E18 to 1E20 cm -3 , more conveniently in the range of about 1E19- to 5E19 cm -3 and preferably about 2E19 cm -3 , although higher and lower values can also be used and other doping types. Thickness 202 is usefully in the range of about 0.5 to 3.0 micrometers, more conveniently in the range of about 1.0 to 2.0 micrometers and preferably about 1.5 micrometers, but larger and smaller values may also be used. Further SC region or layer 74 of thickness 741 with upper surface 71 is formed above buried layer 72 . Epitaxial growth is a useful means for providing further SC region of layer 74 , but other well known techniques may also be used to form structure 311 resulting from manufacturing stage 211 . Layer or region 74 is desirably P type with doping density usefully in the range of about 5E14 to 5E16 cm -3 , more conveniently in the range of about 1E15 to 1E16 cm -3 and preferably about 2E15 cm -3 , although higher and lower values can also be used and other doping types. Thickness 741 is usefully in the range of about 1.0 to 10.0 micrometers, more conveniently in the range of about 2.0 to 5.0 micrometers and preferably about 4.0 micrometers, but larger and smaller values may also be used. Structure 311 results. The combination of substrate 70 , buried layer 72 and further SC region or layer 74 is also referred to as semiconductor body 70 , 72 , 74 or semiconductor containing body 70 , 72 , 74 having an upper surface 71 .
[0042] Referring now to manufacturing stage 212 of FIG. 12 , mask 612 is applied above surface 71 with closed portion 612 - 2 and opening 612 - 1 . Ion implant 512 is desirably used to form superposed doped region 80 of thickness or depth 801 and doped region 82 of thickness or depth 821 through opening 612 - 1 . A chain implant is preferred although separate implants may also be used in other embodiments. Region 80 is conveniently N type and region 82 is conveniently P type, but other doping types may be used in other embodiments. Phosphorus is a suitable dopant for forming region 80 and boron is a suitable dopant for forming regions 82 , with the implant energies being selected to provide depths 801 , 821 respectively. Region 80 has a peak doping density usefully in the range of about 1E16 to 1E17 cm -3 , more conveniently in the range of about 2E16 to 5E16 cm -3 and preferably about 4E16 cm -3 , although higher and lower values can also be used and other doping types. Depth 801 is usefully in the range of about 0.5 to 2.5 micrometers, more conveniently in the range of about 1.0 to 2.0 micrometers and preferably about 1.0 micrometers, but larger and smaller values may also be used. Region 82 has a peak doping density usefully in the range of about 1E16 to 1E17 cm -3 , more conveniently in the range of about 2E16- to 5E16 cm -3 and preferably about 4E16 cm -3 , although higher and lower values can also be used and other doping types. Depth 821 usefully in the range of about 0.5 to 2.5 micrometers, more conveniently in the range of about 1.0 to 2.0 micrometers and preferably about 1.0 micrometers, but larger and smaller values may also be used. Structure 312 results. Analogous process steps may be used to form doped regions 154 (e.g., N type) and 156 (e.g., P type) of FIG. 10 .
[0043] Referring now to manufacturing stage 213 of FIG. 13 , mask 612 is removed and shallow trench isolation (STI) regions 84 of thickness or depth 841 from surface 71 are desirably formed at the indicated location using teachings well known in the art. STI regions 84 may be omitted in whole or in part in other embodiments. Silicon dioxide is a non-limiting example of a suitable dielectric for STI regions 84 but other well known insulators may also be used. Thicknesses or depth 841 is usefully in the range of about 0.1 to 0.6 micrometers, more conveniently in the range of about 0.2 to 0.5 micrometers and preferably about 0.35 micrometers, but larger and smaller values may also be used. Before, during or after the formation of STI regions 84 , relatively deep dielectric trench isolation (DTI) wall 100 of depth 104 from surface 71 and width 101 , with or without poly inclusions 103 , is formed, also using teachings well known in the art. While DTI wall 100 is shown as extending from beneath STI region 84 , in other embodiments, DTI wall 100 may extend from surface 71 . Either arrangement is useful. DTI wall 100 extends into portion 701 of substrate 70 beneath BL 72 , so to DC isolate (e.g., N type) portion 722 of BL 72 of FIG. 13 to the left of DTI wall 100 from portion 723 of BL 72 of FIG. 13 to the right of DTI wall 100 . In a preferred embodiment, in plan view (not shown), DTI wall 100 laterally encloses the active regions of LDMOS device 69 - 3 , but other plan view layouts may also be used in other embodiments. Structure 313 results.
[0044] Referring now to manufacturing stage 214 of FIG. 14 , mask 614 is applied having opening 614 - 1 and closed portions 614 - 2 , 614 - 3 . Ion implant 514 is desirably provided to form (e.g., P type) body region 76 of depth or thickness 761 . Region 76 has a peak doping density usefully in the range of about 1E17 to 5E18 cm -3 , more conveniently in the range of about 5E17 to 2E18 cm -3 and preferably about 1E18 cm -3 , although higher and lower values can also be used as well as other doping types. Depth 761 usefully in the range of about 0.5 to 2.0 micrometers, more conveniently in the range of about 1.0 to 1.5 micrometers and preferably about 1.0 micrometers, but larger and smaller values may also be used. Structure 314 results. Region 148 (e.g., P type) of FIG. 10 can be formed in an analogous manner, having similar depth or thickness and doping usefully in the range of about 1E16 cm -3 to 1E 17 cm -3 , more conveniently in the range of about 2E16 cm -3 to 8E16 cm -3 and preferably about 5E 16 cm -3 , but other values may also be used.
[0045] Referring now to manufacturing stage 215 of FIG. 15 , mask 614 is removed and mask 615 is applied having opening 615 - 1 and closed portion 615 - 2 . Ion implant 515 is desirably used to form (e.g., N type) sinker regions 86 , 88 of depth sufficient to provide Ohmic (non-rectifying) contact to buried layer 72 . Other doping means well known in the art may also be used in other embodiments. Phosphorus is a non-limiting example of a suitable dopant. Sinker regions 86 , 88 have a doping density usefully in the range of about 1E18 to 5E19 cm -3 , more conveniently in the range of about 2E18 to 1E19 cm -3 and preferably about 5E18 cm -3 , although higher and lower values can also be used as well as other doping types. Structure 315 results. Referring now to manufacturing stage 216 of FIG. 16 , mask 614 is removed and gate 25 provided overlying a suitable gate insulator on surface 71 in the indicated location, using means well known in the art. Gate 25 of FIGS. 16-18 is analogous to gate 45 of FIG. 10 . Structure 316 results.
[0046] Referring now to manufacturing stage 217 of FIG. 17 , mask 617 is provided on surface 71 , having openings 617 - 1 , 617 - 2 , 617 - 3 and closed portions 617 - 4 , 617 - 5 , 617 - 6 . Implant 517 is provided through openings 617 - 1 , 617 - 2 , 617 - 3 so as to form (e.g., N+) source region 22 in body region 76 , drain region 24 in drift region 80 and contact region 89 in sinker region 88 . Phosphorus is a non-limiting example of a suitable dopant for regions 22 , 24 , 89 with a doping density usefully in the range of about 1E19 to 1E21 cm -3 , more conveniently in the range of about 5E19 to 5E20 cm -3 and preferably about 1E20cm -3 , although higher and lower values can also be used and other doping types. Regions 22 , 24 , 89 may be relatively shallow, with depth 891 usefully in the range of about 0.1 to 0.5 micrometers, more conveniently in the range of about 0.2 to 0.4 micrometers and preferably about 0.2 micrometers, but larger and smaller values may also be used. Structure 317 results. Region 46 of FIG. 10 may be formed in substantially the same way.
[0047] Referring now to manufacturing stage 218 of FIG. 18 , mask 617 is removed and mask 618 provided on surface 71 , having opening 618 - 1 and closed portions 618 - 2 , 618 - 3 . Implant 518 is provided through opening 618 - 1 to form (e.g., P+) body contact region 78 in body region 76 . Boron is a non-limiting example of a suitable dopant for region 78 with a doping density usefully in the range of about 1E19 to 1E21 cm -3 , more conveniently in the range of about 5E19 to 5E20 cm -3 and preferably about 1E20cm -3 , although higher and lower values can also be used as well as other doping types. Depth 781 is usefully in the range of about 0.1 to 0.5 micrometers, more conveniently in the range of about 0.2 to 0.4 micrometers and preferably about 0.2 micrometers, but larger and smaller values may also be used. Structure 318 results. Regions 42 , 44 (e.g., P+) of FIG. 10 may be formed in substantially the same way.
[0048] Referring now to manufacturing stage 219 , mask 618 is removed. Structure 319 results. Conductive contacts are then made to regions 22 , 24 , 89 , and 78 using teachings well known in the art. The interconnections to couple such regions to source, drain and gate terminals and to couple contact 89 of sinker region 88 to drain region 24 or drain terminal 28 are also formed using teachings well known in the art, thereby providing substantially finished device 69 - 3 of FIG. 9 . Substantially finished device 69 ′- 3 of FIG. 10 is similarly provided by making connections to and between the analogous regions of device 69 ′- 3 of FIG. 10 .
[0049] According to a first embodiment, there is provided an electronic device ( 69 , 69 ′), comprising, an MOS transistor ( 63 , 65 ) having current carrying terminals including a source ( 22 , 42 ) and a drain ( 24 , 44 ) in a semiconductor containing body ( 70 , 72 , 74 ) having an upper surface ( 71 ), a DC isolated buried layer ( 72 ) underlying the MOS transistor ( 63 , 65 ), and a charge pump capacitance ( 94 , 94 ′) coupled between one of the current carrying terminals ( 22 , 42 ; 24 , 44 ) and the DC isolated buried layer ( 72 ). According to a further embodiment, the MOS transistor ( 63 ) is an N channel transistor and the DC isolated buried layer ( 72 ) is N type. According to a still further embodiment, the MOS transistor ( 65 ) is a P channel transistor and the DC isolated buried layer ( 72 ) is N type. According to a yet further embodiment, the charge pump capacitance ( 94 - 1 , 94 ′- 1 ) is external to the MOS transistor ( 63 , 65 ). According to a still yet further embodiment, the charge pump capacitance ( 94 - 2 , 94 ′- 2 ) is formed over the upper surface ( 71 ). According to a yet still further embodiment, the charge pump capacitance ( 94 - 2 , 94 ′- 2 ) is a deposited capacitance. According to another embodiment, the charge pump capacitance ( 94 - 3 , 94 ′- 3 ) is formed under the upper surface ( 71 ). According to a still another embodiment, the charge pump capacitance ( 94 - 3 , 94 ′- 3 ) comprises a dielectric trench isolation wall ( 100 ) penetrating substantially from the upper surface ( 71 ) through the DC isolated buried layer ( 72 ) underlying the MOS transistor ( 63 , 65 ). According to a yet another embodiment, the dielectric trench isolation wall ( 100 ) has a first sinker region ( 86 ) on a first side thereof facing toward the MOS transistor ( 63 , 65 ) and a second sinker region ( 88 ) on a second side thereof facing away from the MOS transistor ( 63 , 65 ), wherein the first sinker region ( 86 ) is Ohmically coupled to the DC isolated buried layer ( 72 ) and the second sinker region ( 88 ) is Ohmically coupled to one of the source ( 42 ) and drain ( 24 ) of the MOS transistor ( 63 , 65 ) and the first ( 86 ) and second ( 88 ) sinker regions are DC isolated from each other by the dielectric trench isolation wall ( 100 ). According to a till yet another embodiment, the MOS transistor ( 63 , 65 ) is an LDMOS transistor ( 69 , 69 ′).
[0050] According to a second embodiment, there is provided an LDMOS transistor ( 69 , 69 ′), comprising, a buried SC layer region ( 72 ), a further SC region ( 74 ) overlying the buried layer region ( 72 ) and having an upper surface ( 71 ), a MOSFET ( 63 , 65 ) formed in the further SC region ( 74 ), wherein the MOSFET ( 63 , 65 ) comprises, a body region ( 76 , 154 ) having therein a source region ( 22 , 42 ) of the MOSFET ( 63 , 65 ), and a carrier drift region ( 80 , 148 ) laterally separated from the body region ( 76 , 154 ) and having therein a drain region ( 24 , 44 ) of the MOSFET ( 63 , 65 ), and a charge pump capacitance ( 94 , 94 ′) coupled between the buried layer region ( 72 ) and one of the drain region ( 24 ) and the source region ( 42 ) of the MOSFET ( 63 , 65 ). According to a further embodiment, the charge pump capacitance ( 94 - 1 , 94 ′- 1 ; 94 - 2 , 94 ′- 2 ) is formed substantially over the upper surface ( 71 ). According to a still further embodiment, the charge pump capacitance ( 94 - 1 , 94 ′- 1 ; 94 - 2 , 94 ′- 2 ) is formed substantially on the upper surface ( 71 ). According to a yet further embodiment, the charge pump capacitance ( 94 - 3 , 94 ′- 3 ) is formed substantially beneath the upper surface ( 71 ). According to a still yet further embodiment, the charge pump capacitance ( 94 , 94 ′) has a capacitance value adapted to pump charge into the buried layer ( 72 ) in response to a fast voltage transient voltage ( 95 ) applied between the source ( 22 , 42 ) and drain ( 24 , 44 ) so as to temporarily raise a voltage of the buried layer ( 72 ) by at least 5% of the magnitude of fast voltage transient voltage ( 95 ). According to a yet still further embodiment, the charge pump capacitance ( 94 , 94 ′) has a capacitance value adapted to pump charge into the buried layer ( 72 ) in response to a fast voltage transient ( 95 ) applied between the source ( 22 , 42 ) and drain ( 24 , 44 ) so as to temporarily raise the voltage of the buried layer ( 72 ) by at least 10% of the magnitude of fast voltage transient voltage ( 95 ).
[0051] According to a third embodiment, there is provided a method for providing an LDMOS transistor ( 69 , 69 ′), comprising, forming a buried layer ( 72 ) of a first conductivity type, forming a further SC region ( 74 ) of a second, opposite, conductivity type on the buried layer ( 72 ), and having an upper surface ( 71 ), forming a first doped region ( 80 , 154 ) of the first conductivity type in a first portion of the further SC region ( 74 ) extending at least in part to the upper surface ( 71 ) and overlying at least part of the buried layer ( 72 ), forming a dielectric trench isolation wall ( 100 ) extending though the further SC region ( 74 ) and the buried layer ( 72 ), and laterally separated from the first doped region ( 80 , 154 ), forming another doped region ( 76 , 148 ) of the second conductivity type extending into the further semiconductor region ( 74 ) between the first doped region ( 80 , 154 ) and the dielectric trench isolation wall ( 100 ) and laterally separated from the first doped region ( 80 , 154 ) by a portion of the further semiconductor region ( 74 ), forming first ( 86 ) and second ( 88 ) sinker regions of the first conductivity type extending substantially from the surface ( 71 ) through the further semiconductor region ( 74 ) to make Ohmic contact to the buried layer ( 72 ), the first sinker region ( 86 ) located on a first side of the dielectric trench isolation wall ( 100 ) toward the first doped region ( 80 , 154 ) and the second sinker region ( 88 ) located on a second side of the dielectric trench isolation wall ( 100 ) facing away from the first doped region ( 80 , 154 ) so that, (i) the first ( 86 ) and second ( 88 ) sinker regions and (ii) portions ( 722 , 723 ) of the buried layer ( 72 ) lying on either side of the dielectric trench isolation wall ( 100 ) are DC isolated from each other, providing a second sinker Ohmic contact region ( 89 ) of the first conductivity type in the second sinker region ( 88 ), wherein if the LDMOS transistor ( 69 , 69 ′) is an N channel LDMOS transistor ( 69 ), providing a drain region ( 24 ) of the first conductivity type in the first doped region ( 80 ) and Ohmically connecting the second sinker contact region ( 89 ) to the drain region ( 24 ), and wherein if the LDMOS transistor ( 69 , 69 ′) is a P channel LDMOS transistor ( 69 ′), providing a source region ( 42 ) of the second conductivity type in the first doped region ( 154 ) and Ohmically connecting the second sinker contact region ( 89 ) to the source region ( 42 ). According to a further embodiment, the method further comprises, forming a gate insulator with an overlying gate conductor ( 25 , 45 ) on the upper surface ( 71 ) above at least the portion of the further semiconductor region ( 74 ) between the first doped region ( 80 , 154 ) and the another doped region ( 76 , 148 ). According to a still further embodiment, the LDMOS transistor ( 69 , 69 ′) is an N channel LDMOS transistor ( 69 ) and the source region ( 22 ), the drain region ( 24 ) and the second sinker Ohmic contact region ( 89 ) are formed substantially at the same time. According to a yet further embodiment, the LDMOS transistor ( 69 , 69 ′) is a P channel LDMOS transistor ( 69 ′), and the second sinker Ohmic contact region ( 89 ) and a body contact region ( 46 ) to the first doped region ( 154 ) are formed at substantially the same time.
[0052] While at least one exemplary embodiment and method of fabrication 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 and their legal equivalents. | Transistors ( 21, 41 ) employing floating buried layers (BL) ( 72 ) may exhibit transient breakdown voltage (BVdss) TR significantly less than (BVdss) DC . It is found that this occurs because the floating BL ( 72 ) fails to rapidly follow the applied transient, causing the local electric field within the device to temporarily exceed avalanche conditions. (BVdss) TR of such transistors ( 69. 69′ ) can be improved to equal or exceed (BVdss) DC by including a charge pump capacitance ( 94, 94′ ) coupling the floating BL ( 72 ) to whichever high-side terminal ( 28, 47 ) receives the transient. The charge pump capacitance ( 94, 94′ ) may be external to the transistor ( 69, 69′ ), may be formed on the device surface ( 71 ) or, may be formed internally to the transistor ( 69 - 3, 69′ - 3 ) using a dielectric deep trench isolation wall ( 100 ) separating DC isolated sinker regions ( 86, 88 ) extending to the BL ( 72 ). The improvement is particularly useful for LDMOS devices. | 7 |
FIELD OF THE INVENTION
The present invention relates to the painting industry and more specifically to the provisioning of painting implements.
BACKGROUND OF THE INVENTION
Painting is the practice of applying paint, pigment, color or other medium to a surface (support base). The medium is commonly applied to the base with a brush but other objects can be used including rollers and sprayers. Painting is also used to define a common trade among craftsmen and builders. Painters require many tools in their activities including paint, brushes, and paint rollers are required as are paint trays and paint cans together with other items which may include drop-clothes, scrapers, tape, and screwdrivers. Irrespective of the medium and surface it is very difficult even for professional craftsmen to easily manage these items during their painting activities especially when painting a large room, corridor etc.
At the end of a day's painting activities the painter then performs a series of cleanup activities such as cleaning their brush or brushes, cleaning the roller, and washing the paint tray. Either that or they dispose of them all and begin the next day with new implements that are expensive and not environmentally conscious. Accordingly it would be beneficial to provide the painter with a system that provides them with the ability to easily move their painting implements around during their time painting as well as managing their painting implements for a period of time after a painting session so that they do not need to spend time cleaning before finishing that painting session or disposing of their implements after the session and using new implements in the next session.
Within the prior art systems for the storage and management of painting implements such as presented by R. Mill in U.S. Patent Application 2010/0,108,685 “Paint Assembly”; D. Bastarache in U.S. Patent Application 2006/0,108,192 “Painter's Container”; J. K. Verbrugge et al in U.S. Patent Application 2005/0,098,564 “Packaging for Paint Comprising Lid with Integral Roller Tray”; M. G. McKenna in U.S. Pat. No. 4,903,869 “Brush Storage and Fluid Dispensing Device”; and R. A. Heisler in U.S. Pat. No. 3,828,389 “Unitary Container having a Hinged Panel with a Tray Configuration” suffer drawbacks from the painter's viewpoint. Amongst these are limitations in handling painting implements between painting sessions without cleaning them, restrictions on replacing elements within the systems, and flexibility.
Typically, painters will seek to minimize expenses such buying those paint trays on special offer, using disposable paint tray liners, using quart paint cans for small painting jobs, etc. Accordingly it would be beneficial to provide painters with a system that provided flexibility in handling paint cans as well as paint trays, different sizes of paint cans, variations in paint tray dimensions, etc as well as providing an easily maneuvered system during their painting session to reflect their motion and areas being painted that can be quickly closed at the end of a painting session or their change of paint.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
SUMMARY OF THE INVENTION
It is an object of the present invention to mitigate disadvantages of the prior art and provide improvements to the painting industry and more specifically to the provisioning of painting implements.
In accordance with an embodiment of the invention there is provided a method comprising providing
a first element comprising at least a top surface, a bottom surface, and at least one first feature of a plurality of first features forming part of the top surface and having a first predetermined footprint and first depth, each first feature dimensioned according to a standard paint can type; a second element comprising at least a recess of predetermined dimensions to accept a paint tray; wherein
in a first configuration the second element sits atop the top surface of the first element thereby allowing a painter to access the paint tray within the recess; and in a second configuration the first element sits atop the second element such that the recess is covered and the paint tray enclosed.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:
FIG. 1 depicts typical painting elements of a painter and a painting environment according to the prior art;
FIG. 2 depicts the variations in paint rollers and paint trays available to a painter that impact a painting transportation and storage system according to an embodiment of the invention;
FIG. 3 depicts a painting transportation and storage system according to the prior art of Mill in US Patent Application 2010/0,108,685;
FIG. 4 depicts a painting transportation and storage system according to the prior art of Bastarche in US Patent Application 2006/0,108,192;
FIG. 5 depicts a painting transportation and storage system according to the prior art of Verbrugge in US Patent Application 2005/0,098,564;
FIG. 6 depicts a painting transportation and storage system according to the prior art of McKenna in U.S. Pat. No. 4,903,869;
FIG. 7 depicts a painting transportation and storage system according to the prior art of Heisler in U.S. Pat. No. 3,828,389;
FIG. 8 depicts an element of a painting transportation and storage system according to an embodiment of the invention in a first configuration;
FIG. 9 depicts an element of a painting transportation and storage system according to an embodiment of the invention in a second configuration;
FIG. 10 depicts an element of a painting transportation and storage system according to an embodiment of the invention in a third configuration;
FIG. 11 depicts the element of a painting transportation and storage system according to an embodiment of the invention as described in respect of FIGS. 8 and 9 ;
FIG. 12 depicts a painting transportation and storage system according to an embodiment of the invention in a fourth configuration;
FIG. 13 depicts a painting transportation and storage system according to an embodiment of the invention in use and storage configurations;
FIG. 14 depicts a painting transportation and storage system according to an embodiment of the invention for storing different painting implements;
FIG. 15 depicts a painting transportation and storage system according to an embodiment of the invention in use and storage configurations;
FIG. 16 depicts a painting transportation and storage system according to an embodiment of the invention in different use and storage configurations;
FIG. 17 depicts elements of a painting transportation and storage system according to an embodiment of the invention.
DETAILED DESCRIPTION
The present invention is directed to the painting industry and more specifically to the provisioning of painting implements.
The ensuing description provides exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims.
PAINT: Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. The common constituents of paint are pigments, binder, solvent, and additives.
Pigments are granular solids incorporated into the paint to contribute color, toughness, texture, give the paint some special properties or simply to reduce the cost of the paint. Alternatively, some paints contain dyes instead of or in combination with pigments. Pigments can be classified as either natural or synthetic types. Natural pigments include various clays, calcium carbonate, mica, silicas, and talcs. Synthetics would include engineered molecules, calcined clays, blanc fixe, precipitated calcium carbonate, and synthetic pyrogenic silicas. Hiding pigments, in making paint opaque, also protect the substrate from the harmful effects of ultraviolet light and include titanium dioxide, phthalo blue, red iron oxide, and many others. Fillers are a special type of pigment that serve to thicken the film, support its structure and simply increase the volume of the paint. Fillers are usually made of cheap and inert materials, such as diatomaceous earth, talc, lime, barytes, clay, etc. Floor paints that will be subjected to abrasion may even contain fine quartz sand as a filler. Not all paints include fillers whilst some paints contain very large proportions of pigment/filler and binder.
The binder, commonly referred to as the vehicle, is the actual film forming component of paint. It is the only component that must be present whereas other components listed below are included optionally, depending on the desired properties of the cured film. The binder imparts adhesion, binds the pigments together, and strongly influences such properties as gloss potential, exterior durability, flexibility, and toughness. Binders include synthetic or natural resins such as cement, alkyds, acrylics, vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes, polyesters, melamine resins, epoxy, or oils and are categorized according to drying, or curing mechanism. The four most common are simple solvent evaporation, oxidative crosslinking, catalyzed/cross linked polymerization, and coalescence.
Latex paint, which is the dominant paint type within residential and general commercial applications, is a water-borne dispersion of sub-micrometre polymer particles. The term “latex” in the context of paint simply means an aqueous dispersion and are generally prepared by emulsion polymerization. Latex paints cure by a process called coalescence where first the water, and then the trace, or coalescing, solvent, evaporate and draw together and soften the latex binder particles and fuse them together into irreversibly bound networked structures, so that the paint will not re-dissolve in the solvent/water that originally carried it.
Besides the three main categories of ingredients, paint can have a wide variety of miscellaneous additives, which are usually added in very small amounts and yet give a very significant effect on the product. Some examples include additives to modify surface tension, improve flow properties, improve the finished appearance, increase wet edge, improve pigment stability, impart antifreeze properties, control foaming, control skinning, etc. Other types of additives include catalysts, thickeners, stabilizers, emulsifiers, texturizers, adhesion promoters, UV stabilizers, flatteners (de-glossing agents), biocides to fight bacterial growth, and the like. Additives normally do not significantly alter the percentages of individual components in a formulation
STAIN: A stain, typically employed on wood, consists of a colorant suspended or dissolved in a ‘vehicle’ or solvent. The suspension agent can be water, alcohol, petroleum distillate, or the actual finishing agent (shellac, lacquer, varnish, polyurethane, etc.). Colored or ‘stained’ finishes, like polyurethane, do not penetrate the pores of the wood to any significant degree and will disappear when the finish itself deteriorates or is removed intentionally. Two types of colourants are used, pigments and dyes. The difference is in the size of the particles. Dyes are microscopic crystals that dissolve in the vehicle and pigments are suspended in the vehicle and are much larger. Dyes will color very fine grained wood, like cherry or maple, which pigments will not. Those fine-grained woods have pores too small for pigments to attach themselves to. Pigments contain a binder to help attach themselves to the wood.
The type of stain will either accentuate or obscure the wood grain and neither is superior to the other. Most commercial stains contain both dye and pigment and the degree to which they stain the appropriate wood is mostly dependent on the length of time they are left on the wood. Pigments, regardless of the suspension agent, will not give much color to very dense woods but will deeply color woods with large pores (e.g. pine). Dyes are translucent and pigments are opaque. Gel stains are more akin to paint and have little penetrating ability
SEALANT: A sealant may be viscous material that has little or no flow characteristics and wither stays where it is applied or is thin and runny so as to allow it to penetrate the substrate by means of capillary reaction. Anaerobic acrylic sealants generally referred to as impregnants are the most desirable as they are required to cure in the absence of air, unlike surface sealants that require air as part of the cure mechanisum that changes state to become solid, once applied, and is used to prevent the penetration of air, gas, noise, dust, fire, smoke or liquid from one location through a barrier into another. Typically, sealants are used to close small openings that are difficult to shut with other materials, such as concrete, drywall, etc. Desirable properties of sealants include insolubility, corrosion resistance, and adhesion. Uses of sealants vary widely and sealants are used in many industries, for example, construction, automotive and aerospace industries.
PAINTING IMPLEMENTS: Painters typically apply paint using direct manual application through use of paint brushes and paint rollers or through spraying. In manual application the painter will repeatedly insert the painting implement, e.g. paint brush or paint roller, into the liquid paint and apply the liquid paint transferred to the surface being painted before repeating the process. At the beginning of painting the painter will open the container containing the paint and either inserts the bristles of the paint brush directly into the paint within the container or into paint within another paint container, such as a paint tray, into which the paint has been decanted from the original paint container. If using a paint roller then the painter will have decanted the paint into a paint tray as generally paint rollers which are designed to increase speed of painting are wider than the original container of paint.
Paint Brush: The sizes of brushes used for painting and decorating are given in given in millimeters or inches, and refers to the width of the head of the paint brush. Common sizes are ⅛ in, ¼ in, ⅜ in, ½ in, ⅝ in, ¾ in, ⅞ in, 1 in, 1¼in, 1½ in, 2 in, 2½ in, 3 in, 3½ in, and 4 in (10 mm, 20 mm, bob 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm). In some instances the end of the brush has bristles providing a predetermined geometry, e.g. a tapered length across the width of the brush (commonly known as chiseled), to enhance their use in certain painting situations such as defining edges and tight corners or painting more precisely. Bristles may be natural or synthetic material. If the filaments are synthetic, they may be polyester, nylon or a blend of nylon and polyester. Filaments can be hollow or solid and can be tapered or untapered, wherein brushes with tapered filaments give a smoother finish. Handles may be wood or plastic whilst the ferrules that surround and grip the filaments whilst attaching to the handle are metal, usually nickel-plated steel.
Paint Roller: A paint roller is a paint application tool used for painting large flat surfaces rapidly and efficiently and typically consists of two parts: a “roller frame,” (commonly referred to as a cage) and a “roller cover” (commonly referred to as a cover or roller cover). The roller cover absorbs the paint and transfers it to the painted surface. The roller frame attaches to the roller cover. A painter holds the roller by the handle section. The roller frame is reusable. It is possible to clean and reuse a roller cover, but it is also typically disposed of after use. Paint rollers are also particularly suited for texture painting where the roller cover has texture which may be for example from pile fabric covering secured to a cylindrical core or through physical surface height variations with foam rubber rollers are also made. Rollers may be specified by their length, inner diameter and hence the roller cage they are compatible with, and the depth of the pile where provided (commonly referred to as the nap). Common roller lengths are 4″, 6″, 6½″, 7½″, 9½″, 14″, and 18″ (100 mm, 150 mm, 165 mm, 190 mm, 240 mm, 305 mm, and 457 mm) whilst common naps are ¼″, ⅜″, ¾″, 1″ (6 mm, 9.5 mm, 19 mm, 25 mm) where shorter naps tend to result in smoother painted surfaces. Paint rollers may also be mounted to the end of extending poles thereby allowing high surfaces to be painted without requiring the painter employ a ladder or such a high ladder.
PRIOR ART: Referring to FIG. 1 there are depicted painting implements for painters including paint brush, paint roller, extending pole, and paint tray together with paint cans providing different quantities of paint according to the type of paint and/or quantity purchased including for example pint, quart, gallon, and 5 gallon. Also depicted is a typical commercial painting application wherein the painters are painting a large area along an extended surface, in this case the walls of a corridor. Now referring to FIG. 2 there is depicted an example of the complexity of managing painting implements for a painter with respect to paint trays and paint rollers. As depicted a painter may select a paint tray 210 , a paint tray liner 230 , a paint roller cage 220 , and paint roller 240 to provide the painting combination 250 they use. However, whilst paint rollers 240 and paint roller cages 220 are essentially standardized there is no such standardization in paint trays 210 and paint tray liners 230 .
Accordingly the paint trays 210 vary in materials, e.g. aluminum, light sheet steel, and plastic as well as outer dimensions of length, width, height together with some having projections to support placement on ladders. Similarly, paint tray liners vary in dimensions and materials, which although typically plastic, means that the thickness of the paint liner trays may vary substantially. Accordingly some paint tray liners may be sufficiently rigid that painters may use discretely without a supporting paint tray. It would therefore be evident that painters will typically over a reasonable period of time exhibit little brand loyalty as such painting implements will be purchased on aspects such as ease of availability and cost.
Referring to FIG. 3 there is depicted a painting transportation and storage system (PTSS) according to the prior art of Mill in US Patent Application 2010/0,108,685. Mill teaches to a stackable storage system comprising lid 310 , top storage section 320 , tray cover 330 , paint tray 340 , and bottom storage section 350 . Each of the lid 310 , top storage section 320 , and tray cover 330 have pneumatic fittings such that when stacked together with the paint tray 340 and bottom storage section 350 and the catches are closed a vacuum pump can be attached to remove the air within the lid 310 , top storage section 320 , tray cover 330 , and paint tray 340 so that, according to Mill, paint within these elements does not harden between painting sessions. However, it would be evident that the system has multiple points of failure due to dependency on multiple seals, pneumatic fittings, and catches. For example, a single drop of paint into the orifice of the pneumatic fitting on the tray cover 330 may block this unknown to the painter such that the paint tray 340 does not get pumped down. It would also be evident that the system would have a high retail price and does not benefit the painter substantially during painting apart from providing a paint tray.
Referring to FIG. 4 there is depicted a PTSS according to the prior art of Bastarche in US Patent Application 2006/0,108,192. As depicted the system comprises an enclosure comprising base and lid that are hinged along one edge. Within each of the lid and base are fittings allowing the painter to store paint brushes, paint rollers, paint roller cages, paint scrapers, and paint tray. The enclosure has wheels allowing it to be moved but only with a large vertical element of the lid. It would be evident that the enclosure is intended to be employed with clean implements as the tray is turned onto its side for transportation. Further the enclosure does not provide means to accommodate different sizes of paint tray. Accordingly, Bastarche teaches to an equivalent of a decorators pasting table that is transported between locations as the painter moves from one job to another rather than supporting storage during painting sessions associated with a single painting contract or job.
FIG. 5 depicts a PTSS according to the prior art of Verbrugge in US Patent Application 2005/0,098,564 wherein a paint container has a folding lid which when opened and supported provides a paint tray-like surface for a roller. The container of Verbrugge being provided with paint either through a decanting process from a paint can or as part of the supply process wherein the container is provided with the paint at the time of purchase by the painter or another person purchasing the paint for the painter. The container of Verbrugge does not allow a painter to exploit low cost disposable paint tray liners such that the container overall is essentially disposed of then the paint within it is consumed, where it is procured with the paint inside at the time of purchase or when the painter has finished with that paint colour.
Now referring to FIG. 6 there is depicted a PTSS according to the prior art of McKenna in U.S. Pat. No. 4,903,869. McKenna teaches to a paint tray with a lid wherein the paint tray comprises towards the bottom at one end a user controlled valve such that paint from a reservoir beneath the paint tray may flow into the paint tray. Accordingly, as with Verbrugge the reservoir may be filled after purchase of the paint tray by decanting paint from a paint can or be purchased pre-filled. The container of McKenna like that of Verbrugge does not allow a painter to exploit low cost disposable paint tray liners such that the container overall is essentially disposed of then the paint within it is consumed, where it is procured with the paint inside at the time of purchase or when the painter has finished with that paint colour.
Referring to FIG. 7 there is depicted a PTSS according to the prior art of Heisler in U.S. Pat. No. 3,828,389 which is similar to that of Verbrugge in that a container is provided with a hinged lid that when opened on its inner surface provides the painter with a surface akin to a paint tray. Accordingly, Heisler suffers the same drawbacks as that of Verbrugge.
Accordingly it is evident that the prior art whilst attempting to address some of the requirements of painters each solution has drawbacks in terms of cost, implementation, usability etc that have meant that today no such system is currently available for consumer or commercial painters.
PAINTING IMPLEMENT MANAGEMENT SYSTEM: Accordingly when painting the painter must repeatedly insert/remove/apply their chosen paint applicator, be it a paint roller (referred to within this specification as a roller) or paint brush (referred to within this specification as a brush). This may require repeated decanting of paint from the paint container, commonly referred to as a paint can when containing a quart or gallon of paint and a paint drum when containing five (5) gallons of paint, to another container which is typically a paint tray which provides a first region for paint and a second region allowing the roller to be rolled such that a uniform application, or near uniform application, of paint is on the roller prior to rolling it onto the surface being painted.
Referring to FIG. 8 there is depicted a first element 800 of a painting transportation and storage system (PTSS) according to an embodiment of the invention in a first configuration. As depicted first element 800 comprises an essentially rectangular plate tray with four mounting points 850 which may for example have inserted into them rollers 890 or another means of providing low friction motion of the first element 800 across a floor of an area being painted by a painter. Formed within the first element 800 are a plurality of features whose dimensions are based upon standard paint cans including first region 840 A defined by four ridged protrusions 845 that are dimensioned according to the base of a five (5) gallon paint drum 810 (or can). Also disposed circularly symmetric with first region 840 A are second and third regions 840 B and 840 C respectively which are recessed into the first element surface to accept the base of one (1) gallon and quart paint cans 820 and 830 respectively. Also disposed within first element 800 is fourth region 840 D comprising a raised region which is similarly dimensioned to fit within the recess on the bottom of a quart paint can 830 .
Also included with the first element 800 is a recess 880 across the width of the first element 800 through the portion comprising first to third regions 840 A through 840 C wherein the recess 800 accommodates a paint roller with or without the paint roller cage. By dimensioning the first element 800 according to intended application the recess 880 may accept multiple paint rollers wherein increasingly larger first elements 800 support more of the standard roller options discussed above that are 6½″, 7½″, 9½″, 14″, and 18 ″ wide. For example, a consumer orientated PTSS may provide for paint rollers up to 14″ whilst a commercial PTSS may support 18″ paint rollers. Where the painter wishes to place a paint roller into the recess 880 with the paint roller cage and its corresponding handle then first edge element 870 provides means for the handle of the paint roller cage to be restrained whilst laying in a plane substantially that of the first element 800 . Second edge element 860 adjacent provides for support and restraint of a paint brush. Disposed along the same edge of the first element 800 are lipped recesses 875 that are designed to accept the flanges on the bottom of a paint tray such that a paint tray may be disposed on the first element 800 . However, as will be discussed below these lipped recesses 875 also provide a means of engaging another element of the PTSS which may be placed atop the first element 800 .
Optionally the first and second edge elements 870 and 860 respectively may be designed to hold the items away from the surface of the first element 800 such that for example the brush does not develop a flat portion from the weight of the bristles and paint pushing it down against the first element 800 . Likewise first edge element 870 may cooperate with additional features within recess 880 that keep the surface of the roller away from the surface of the recess 880 such that the roller does not develop a
Now referring to FIG. 9 there is depicted the first element 800 of a PTSS according to an embodiment of the invention in a second configuration. In this instance the first element 800 has been inverted such that the rollers 960 in the four mounting locations 950 are upwards and the first element 800 now slides based upon the friction between the edges of the first element 800 and the surface onto which it is placed. These edges may for example be simply molded plastic where the first element 800 has been injection molded and the edges left as formed or they may have additional elements such as low friction silicone coatings. It is also evident on the lower surface of first element 800 where the recess 880 for the paint roller is positioned together with the first and second raised regions 910 and 920 respectively that correspond to the second and third regions 840 B and 840 C respectively as depicted within FIG. 8 . Likewise third region 940 now corresponds to recess whereas in FIG. 8 it was depicted as fourth region 840 D. Accordingly third region 940 by suitable dimensioning may accept the base of a quart paint can 830 . Circularly symmetrically disposed to third region 940 are projections 935 that define a fourth region 930 that fits the bottom of a one (1) gallon paint can 820 .
Referring to FIG. 10 there is depicted a second element 1000 for a PTSS according to an embodiment of the invention in a third configuration. First to third images 1010 to 1030 respectively depict the second element 1000 as essentially a deep rectangular tray. Within the perspective view the features 1080 on the sides of the second element 1000 can be seen to be recessed grips for a painter to pick the second element 1000 up. Disposed within the base of the second element 1000 are first and second end projections 1070 A and 1070 B respectively at the short edges whilst disposed along predetermined portions of the longer edges first and second groups of side projections are disposed although only first side projections 1075 are visible within the perspective view. Accordingly, the second element 1000 may hold within it a paint tray such as first to third trays 1040 , 1050 , and 1060 respectively wherein according to the dimensions of the paint tray base it will be retained from sliding by one or more projections on the base comprised from the first and second end projections 1070 A and 1070 B respectively, and first side projections 1075 , and second side projections.
It would be evident to one skilled in the art that the paint tray may be a paint tray, a paint tray liner, or a combination of paint tray and paint tray liner. Accordingly, the painter may employ a resilient paint tray with thin flexible paint tray liners which may be disposed of at the end of painting with a particular colour whilst the more expensive resilient paint tray remains within the second element 1000 ready to accept another paint tray liner.
Referring to FIG. 11 there are depicted bottom view 1100 C, first and second side elevations 1100 D and 1100 B respectively, end elevation 1100 E, and plan view 1100 A. Within plan view 1100 A the plurality of features whose dimensions are based upon standard paint cans are shown including first region 840 A dimensioned according to the base of a five (5) gallon paint drum 810 (or can), second and third regions 840 B and 840 C respectively which are recessed into the first element surface to accept the base of one (1) gallon and quart paint cans 820 and 830 respectively, and fourth region 840 D comprising a raised region which is similarly dimensioned to fit within the recess on the bottom of a quart paint can 830 . Also shown are mounting points 850 , recess 880 for a paint roller, first edge element 870 for the handle of the paint roller cage, and second edge element 860 for support and restraint of a paint brush.
Referring to FIG. 12 there is depicted a PTSS according to an embodiment of the invention in a fourth configuration 1200 wherein first element 800 , second element 1000 , and a paint tray 1250 are combined such that the paint tray 1250 is inserted within second element 1000 and these are then mounted atop the first element 800 . Accordingly in this configuration the painter may utilize the paint tray 1250 and easily move this around using the rollers 890 . If the painter in pouring paint from a paint can into the paint tray 850 spills then this is contained within the second element 1000 .
Now referring to FIG. 13 there is depicted a PTSS according to an embodiment of the invention in use and storage configurations 1200 and 1300 respectively. In use configuration 1200 being first element 800 , second element 1000 , and a paint tray 1250 provides an easily maneuvered paint tray. When the painter has finished this painting session, for example at the end of a day, they remove the second element 1000 using the features 1080 , as depicted in FIG. 10 but not identified for clarity in this Figure, with the paint tray 1250 within and any paint therein which they then place onto the floor. They then take the first element 800 and invert before placing this on top of the second element 1000 thereby enclosing the paint tray 1250 . The resulting assembly can then be picked up using features 1080 and transported. The first and second elements 800 and 1000 may be secured together using one or more of the methods well known within the art including case catches for example.
Accordingly the resulting storage configuration 1300 provides a closed container that is easily transported by the painter or left ready for the next painting session wherein the painter removes the first element 800 , inverts and then places second element 1000 onto it. It would be evident that depending upon the roller design for rollers disposed on the bottom of first element 800 , such as rollers 890 , that the rollers may either project significantly above the inverted surface of the first element 800 or be essentially co-planar with the surface of the inverted first element 800 . For example caster type rollers would project but rollers based upon balls with sockets, for example like a trackerball within a mouse, would be essentially co-planar with the surface. Low profile roller designs may provide benefit in some instances by being installed prior to shipment of the first element 800 .
Now referring to FIG. 14 there is depicted a first element 800 of a PTSS according to an embodiment of the invention in first and second configurations 1400 A and 1400 B for storing painting implements. In first configuration 1400 A a paint roller 1410 is disposed within the first element 800 such that the paint roller 1410 has the head sitting within the recess 880 and the handle within first edge element 870 . In second configuration 1400 B a paint brush 1420 is disposed within the first element 800 by having the handle disposed within second edge element 860 . It would be evident to one skilled in the art that first and second edge elements 870 and 860 respectively may have structures formed or provided down the edges of the first element 800 material forming first and second edge elements 870 and 860 respectively to retain the roller handle or paint brush handle. Such structures may include brushes, rubber strips, polymeric strips, etc such that the painting implement is inserted with some pressure into the structure and retained by friction.
Now referring to FIG. 15 there is depicted a PTSS according to an embodiment of the invention in use and storage configurations 1200 and 1500 respectively. In use configuration 1200 being first element 800 , second element 1000 , and a paint tray 1250 provides an easily maneuvered paint tray. When the painter has finished this painting session, for example at the end of a day, they remove the second element 1000 using the features 1080 , as depicted in FIG. 10 but not identified for clarity in this Figure, with the paint tray 1250 within and any paint therein which they then place onto the floor. They then take the first element 800 and place this on top of the second element 1000 thereby enclosing the paint tray 1250 . The resulting assembly can then be picked up using features 1080 and transported.
The first and second elements 800 and 1000 may be secured together using one or more of the methods well known within the art including case catches for example. Accordingly the resulting storage configuration 1500 provides a closed container that is easily transported by the painter or left ready for the next painting session wherein the painter removes the first element 800 , inverts and then places second element 1000 onto it. Within this assembly approach for the first and second elements 800 and 1000 respectively rollers with reasonable depth and hence projection away from the surface of the first element 800 are now between the first element 800 and second element 1000 so that they are inaccessible and not accidentally caught when the user moves the storage configuration 1500 .
It would be evident to one skilled in the art that a PTSS according to embodiments of the invention may be formed from two injection molded elements, the first element 800 and second element 1000 which either have locking features formed therein during molding or attached subsequently to retain the first element 800 onto the second element 1000 in the “closed” configuration wherein the first element is disposed atop the second element 1000 .
Now referring to FIG. 16 there is depicted a PTSS according to an embodiment of the invention in purchase, use and storage configurations by virtue of a schematic flow. Accordingly as depicted a user purchases a pair of elements, first and second elements 1600 A and 1600 B respectively, which are identical for use together with an existing paint tray 1250 . Accordingly the user in use stacks first element 1600 A inside second elements 1600 B and places the paint tray 1250 within thereby allowing them to paint and in instances where the second element 1600 B has rollers also roll the assembly around on the painting activity they are performing. When the user has finished this painting session, for example at the end of a day, they remove the first element 1600 A and paint tray 1250 by picking up the first element 1600 A using grip features provided for that purpose, e.g. features 1080 as described above in respect of FIG. 10 . Next they invert the second element 1600 B and subsequently place this onto the first element 1600 A thereby enclosing the paint tray 1250 . The resulting assembly can then be picked up using the matching grip features on second element 1600 B and transported. Alternatively, the resulting assembly can be rolled into a corner or away based upon first element 1600 A also having rollers.
The first and second elements 1600 A and 1600 B may be secured together using one or more of the methods well known within the art including case catches for example which may be implemented as one per pair of parallel edges for example such that upon combination the first and second elements 1600 A and 1600 B have catches on all four edges through the total of 4 catches between the two elements. Accordingly the resulting storage configuration 1500 provides a closed container that is easily transported by the painter or left ready for the next painting session wherein the painter undoes the catches, removes second element 1600 B, inverts it and then places first element 1600 A into it together with the paint tray 1250 .
Alternatively, first and second elements 1600 A and 1600 B may be intended for 180° between them when mounted to provide the enclosure. It would be evident that in this approach first and second elements 1600 A and 1600 B are stackable and replaceable individually. Optionally, first and second elements 1600 A and 1600 B whilst stackable may have different features such that they are distinguishable elements and hence employed in particular manner. For example, in such a scenario second element 1600 B may be absent features for retaining multiple paint trays or all sizes of paint and the features for holding the paint brush handle and roller cage handle.
Now referring to FIG. 17 there are depicted elements of a PTSS according to an embodiment of the invention. As depicted a base element 1710 is shown in first and second orientations 1710 A and 1710 B respectively, base element 1710 being the wheeled base of the PTSS and accordingly comparable to first element 800 described supra in respect of FIGS. 8, 9 , and 12 to 15 respectively. Also depicted is cover element 1720 shown in third and fourth configurations 1720 A and 1720 B respectively, cover element 1720 being comparable to second element 1000 described supra in respect of FIGS. 10 and 12 as well as second element 1600 B in FIG. 16 . Base and cover elements 1710 and 1720 respectively are shown assembled in fifth and sixth orientations 1730 A and 1730 B such as described supra in respect of 1300 in FIG. 13 . As depicted the base element 1710 differs from first element 800 in that lipped regions 1740 are disposed at the other end than those depicted with first element 800 and lipped recesses 875 . Similarly, fourth region 930 on first element 800 is now holder 1750 with raised sidewalls.
Within the descriptions above in respect of FIGS. 8 through 17 supra the descriptions may have been construed as being related to interior painting however the embodiments of the invention are applicable to interior and exterior painting as well as the interior/exterior application of stains and sealants together with other liquid coatings that may be applied to surfaces in conjunction with one or more of these. However, the PTSS depicted and described in respect of FIGS. 8 through 17 may also be employed in the application or dispersal of other materials including liquids, particulates, and powders for example wherein easy movement, application and storage are required. It would be evident that the overall design of the PTSS may be varied according to the type of application or that different PTSS products may be tailored to different applications as well as supporting additional equipment such as a compressor and liquid tank for spraying applications. Accordingly, features depicted as being circular to accommodate circular containers may be replaced with those of other geometries according to the containers of these other materials.
Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. Implementation of the techniques, blocks, steps and means described above may be done in various ways.
Also, it is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed, but could have additional steps not included in the figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function.
The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.
Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention. | Painters employ multiple painting implements during painting which must be moved around as they move or stored during painting as activities are paused temporarily. Accordingly it would be beneficial to provide a painting transportation and storage system that met such requirements. However, as painters seek to minimize expenses by buying those paint trays on special offer, disposable paint tray liners, quart or gallon paint cans for small painting jobs, etc. it would be beneficial for such a system to provide flexibility in handling paint cans as well as paint trays, different sizes of paint cans, variations in paint tray dimensions, etc as well as providing an easily maneuvered system during their painting session to reflect their motion and areas being painted that can be quickly closed at the end of a painting session or their change of paint. | 1 |
This invention is a continuation-in-part of U.S. patent application Ser. No. 12/700,887 filed Feb. 5, 2010, which is a divisional of U.S. patent application Ser. No. 11/934,392 filed Nov. 2, 2007, now U.S. Pat. No. 7,861,451, which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/905,556 filed Mar. 7, 2007, and this invention is a continuation in part of U.S. patent application Ser. No. 11/652,337 filed Jan. 11, 2007 now U.S. Pat. No. 7,568,304, which is a continuation in part of U.S. patent application Ser. No. 11/485,762 filed Jul. 13, 2006 now U.S. Pat. No. 7,490,429, which is a continuation in part of U.S. patent application Ser. No. 10/725,082 filed Dec. 2, 2003, now U.S. Pat. No. 7,111,424, and U.S. Design patent application Ser. No. 29/259,347 filed May 5, 2006 now U.S. Pat. D566,219.
FIELD OF THE INVENTION
The present invention relates to guns and firearms and more particularly to devices, apparatus, systems and methods of using a foldable accessory adapters or folding rail assemblies for allowing a firearm to be supported by various devices such as but not limited to fore grip/gun handle that can have bipod type legs or only a vertical extension, and or other accessories such as a light or a combination fore grip and light to be foldable underneath the firearm.
BACKGROUND AND PRIOR ART
For many years, there has been considerable amount of prior art for fore grips and bipod devices, that date back to pre-20 th century times, with bipods having a familiar appearance, structure and configuration, where the fore grips and bipods are generally kept in a vertical orientation beneath the firearm.
For example, some known prior art includes but is not limited to U.S. Pat. Nos. 271,251; 1,295,688; 1,355,660; 1,382,409; 1,580,406; 2,386,802; 2,420,267; 2,436,349, and 3,235,997. These patents disclose the respective art in relation to bipods, but do not disclose a fore grip or gun handle with a concealable and collapsible bipod.
U.S. Pat. No. 6,487,807 describes a tripod gun handle that provides a combination pistol grip and pivotal tripod. An examination of this patent reveals a number of problems with this device, and the most obvious problem is that the tripod legs are positioned on the exterior of the handle when not deployed. If the gun with this device attached was being used in wet or muddy environments, either in a deployed or storage position, the ingress of mud and dirt into and around the handle could result in the deployment and storage of the tripod legs being severely restricted due to the mud or foreign matter. Another problem is that deployment requires the rotation of a disengagement cam to force the legs into their deployed position and then a leg locking assembly is rotated to lock the legs into a locked position. Two separate actions are required to deploy and lock the tripod legs into a locked position.
Another problem with these bipods and leg stands is that the fore grip type stands are generally locked in a fixed position, which means an operator would have to physically move and/or physically raise the stand to adjust the firearm to fire a shot. Such physical movements of having to physically cant, tilt and/or lift the stand would be naturally uncomfortable to the operator. In addition such physical movements can cause the firearm to be held in an unsteady position that makes both a steady and reliable shot at an intended target both difficult and potentially impossible.
Another problem with many firearms having fore grips and bipods is that the fore grips remain in fixed vertical type orientations beneath the firearm at all times. Thus, these firearms can be cumbersome to carry since the fore grip is sticking down which can hit or rub against the sides of the human carrier. Also the fixed vertically oriented fore grips make the firearms difficult to store and transport since the lower extending vertical fore grip takes up valuable space and room during transport.
Attempts over the years have been made to allow for allowing for some folding of portions of firearms. See for example, U.S. Pat. Nos. 4,351,224 to Curtis; 4,625,620 to Harris; 5,074,188 to Harris; 5,085,433 to Parsons; 5,711,103 to Keng; 6,470,617 to Gregory; 6,517,133 to Seegmiller et al.; and 6,763,627 to Kaempe. However, none of these references overcomes all of the problems with the prior art described above.
Thus, the need exists for solutions to the problems addressed above.
The novel invention allows stands such as bipods to be able to fold as desired by the firearm operator.
SUMMARY OF THE INVENTION
A primary objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip/gun handle that can fold up along the firearm when not being used.
A secondary objective of the subject invention is to provide devices, apparatus, systems and methods of a detachable firearm fore grip/gun handle that can fold down to extend vertically below when the firearm is being used.
A third objective of the subject invention is to provide devices, apparatus, systems and methods of using a firearm fore grip/gun handle with extendable bipod legs.
A fourth objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip/gun handle that allows for a light to be attached to the fore grip/gun handle.
A fifth objective of the subject invention is to provide devices, apparatus, systems and methods of incorporating a light into a firearm fore grip/gun handle.
A sixth objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip gun handle with a pivotable light.
A seventh objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip gun handle with a foldable light.
An eighth objective of the subject invention is to provide devices, apparatus, systems and methods of using a folding plate assembly for attaching to existing picatinny rails on a firearm, that can support accessories such as foregrips, lights, and the like.
An ninth objective of the subject invention is to provide devices, apparatus, systems and methods of substituting a folding rail assembly for the existing picatinny rails plate on firearms, where the folding rail plate assembly does not enlarge the existing picatinny rail plate used on firearms.
An tenth objective of the subject invention is to provide devices, apparatus, systems and methods of substituting a folding rail assembly for the existing picatinny rails plate on firearms, that uses less material and is less expensive than a folding plate adapter.
A firearm fore grip adapter having an adapter member, an upper portion on the adapter member for allowing the member to be attachable beneath a firearm, and a lower portion pivotally attached to the adapter member, the lower portion for supporting a fore grip thereon, wherein the fore grip can move between a vertical downward position for supporting the firearm to a folded position with fore grip adjacent to the firearm. The upper portion can be an upper clamp for clamping the adapter member underneath of the firearm.
The upper clamp can include clamp edges for sliding about picatinny rails underneath the firearm. The upper clamp can include compressible clamp edges for clamping about picatinny rails underneath the firearm with a rotatable knob/screw.
The lower portion can include rails for allowing the adapter to attach to detachable fore grip. The adapter can include a pullable button for releasing the pivotable lower portion. The adapter can include a depressible button for releasing the pivotable lower portion. The adapter can include a switch for releasing the pivotable lower portion.
The fore grip can have bipod legs. The fore grip can have a light.
The invention can include an adapter member, an upper portion on the adapter member for allowing the member to be attachable beneath a firearm, and a lower portion pivotally attached to the adapter member, the lower portion for supporting another component thereon, wherein the other component can move between a vertical downward position for to a folded position adjacent to the firearm.
The another component can include a light. The another component can include a vertical fore grip. The another component can include both a vertical fore grip and a light. The another component can include a vertical fore grip with a light integrated inside of the fore grip.
A novel method of attaching a foldable accessory mounting plate to a firearm, can include the steps of providing a firearm having opposite facing picatinny rails underneath the firearm, providing a top plate member with an upper surface having a pair of opposite facing grooves, providing a bottom plate member with opposite facing picatinny rails, hingedly attaching one end of the bottom plate member to the top plate member by the hinge, sliding and mating the opposite facing grooves on the upper surface of the top plate member about the picatinny rails underneath the firearm, providing a vertically extending elongated accessory having an upper surface having a pair of opposite facing grooves, sliding and mating the opposite facing grooves on the upper surface of the elongated accessory about the picatinny rails on the bottom plate member, and folding the vertically extending elongated accessory to a horizontal orientation underneath the firearm by the hinge between the top and the bottom plate member.
The accessory can include a light. The accessory can include vertical fore grip. The method can include the steps of deploying a pair of legs with feet beneath the vertical fore grip and expanding the feet on the legs apart from one another. The vertical fore grip can include a light.
Another embodiment of the invention can have telescoping extendable legs that can be individually extended from beneath the fore grip handle.
The invention can be used with fore grips having concealable and collapsible bipod legs. Alternatively, the accessory mount can be used with other types of fore grips such as basic vertical fore grips, or any stands that can be attached to rails such as picatinny rails beneath firearms.
A firearm fore grip with accessory mount holder, can include an elongated handle having a top end and a bottom end and outer sidewalls between the top end and the bottom end, and an accessory mount having a portion that is attached to a portion of the outer sidewalls of the handle, the accessory mount having rails for allowing an accessory to be removably attached to the rails on the accessory mount.
The accessory mount can be molded to a side portion of the outer sidewalls of the handle.
Another embodiment of the firearm adapter can include an adapter member having an upper side and a lower side, a clamp on the upper side of the adapter member for allowing the member to be clamped to picatinny rails located beneath a firearm, a swing plate pivotally attached to the lower side of the adapter member, the swing plate having picatinny side edges for supporting an accessory thereon, and a sliding switch for allowing the swing plate to be released from a horizontal locked position to be able to rotate to a substantially vertical position.
The sliding switch can include an angled raised surface for allowing a finger of a user to push against, and a spring for biasing the sliding switch to the locked position. The sliding switch can include a set screw for adjusting the biasing extension of the spring.
The adapter can include a catch on a free end of the swinging plate for catching onto a protruding end on the sliding switch, so that the swinging plate is held in the locked position, and a spring loaded latch for locking the swinging plate in the substantially vertical position.
The adapter can include both a first spring for biasing the sliding switch to the locked horizontal position, and a second spring for locking the swinging plate to the substantially vertical position.
The accessory supported by the adapter can be a vertical fore grip, a bipod, or a fore grip with collapsible bipod legs. Additionally, the accessory can include a light or laser source.
A novel method of attaching a foldable accessory mounting plate to a firearm, can include the steps of providing a firearm having opposite facing picatinny rails underneath the firearm, clamping upper sides of a top plate member about the picatinny rails, pivotally attaching one end of a bottom plate member to the top plate member, locking the bottom plate member into a folded horizontal position parallel to the top plate member by a sliding switch being moved in one direction, and releasing the bottom plate member to rotate to a substantially vertical position by moving the sliding switch in an opposite direction.
The method can include the steps of spring biasing the sliding switch toward the one position, and/or locking the bottom plate member to the substantially vertical position by a spring.
A folding rail for firearms can be a folding rail assembly that can be substituted for an existing picatinny rails on a firearm. The folding rail can include a plate shaped member having a first end, a second end, a first longitudinal picatinny rail along one side of the plate shaped member between the first end and the second end, and a second longitudinal picatinny rail along an opposite side of the plate shaped member between the first end and the second end, and a hinge for allowing a portion of both the first longitudinal picatinny rail and the second picatinny rail to pivot relative to the plate shaped member, from a horizontal position to a substantially vertical position, wherein the plate shaped member is attached to an undersurface of a firearm.
The folding rail can include a latch for locking the portion of both the first longitudinal picatinny rail and the second picatinny rail to be in the horizontal position relative to the plate shaped member, and mounting holes in the plate shaped member for allowing fasteners to attach the plate shaped member to the undersurface of the firearm.
The plate shaped member can include a forward end with picatinny rails on both sides, and a rearward end with picatinny rails on both sides, with a middle rail section between the foreward end and the rearward end, the middle end being pivotally attached to one of the foreward end or the rearward end. The pivotal middle rail section includes picatinny rails on both sides of the middle rail section.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment, which is illustrated in the accompanying flow charts and drawings.
BRIEF DESCRIPTION OF THE FIGURES
Referring particularly to the drawings for the purposes of illustration only, and not limitation:
FIG. 1 is a bottom rear right perspective view of a folding stacking unit.
FIG. 2 is a bottom front left perspective view of the stacking unit of FIG. 1 .
FIG. 3 is a top rear right perspective view of the stacking unit of FIG. 1 .
FIG. 4 is top front left perspective view of the stacking unit of FIG. 1 .
FIG. 5 is a rear end view of the stacking unit of FIG. 1 .
FIG. 6 is a left side view of the stacking unit of FIG. 1 .
FIG. 7 is a front end view of the stacking unit of FIG. 1 .
FIG. 8 is a top view of the stacking unit of FIG. 1 .
FIG. 9 is a bottom view of the stacking unit of FIG. 1 .
FIG. 10 is an exploded perspective view of the stacking unit of FIG. 1 .
FIG. 11 is an exploded perspective view of the stacking unit of FIG. 1 .
FIG. 12 is an enlarged rear end view of the stacking unit of FIGS. 1 , 5 .
FIG. 13 is an enlarged left side view of the stacking unit of FIGS. 1 , 6 .
FIG. 14 is a cross-sectional view of the stacking unit of FIG. 12 along arrows 14 X.
FIG. 15 is a rear view of the preceding stacking unit with pivot rail folded forward.
FIG. 16 is a left side view of FIG. 15 .
FIG. 17 is a cross-sectional view of FIG. 15 with pivot rail folded forward.
FIG. 17A is an enlarged view of the rail mount plate, release button, pivot rail latch, release button finger access slot and latch spring shown in FIG. 17 .
FIG. 18 is another cross-section view of FIGS. 15 , 17 with pivot rail being folded.
FIG. 18A is an enlarged view of the rail, mount plate, release button, pivot rail latch, release button finger access slot and latch spring shown in FIG. 18 .
FIG. 19 is another cross-section view of FIGS. 15 , 18 - 18 with pivot rail locked.
FIG. 19A is an enlarged view of the rail mount plate, release button, pivot rail latch, release button finger access slot and latch spring shown in FIG. 19 .
FIG. 20 is a rear bottom right perspective view of the folding stacking unit attached to a vertical fore grip, with the stacking unit mounted to a picatinny rail of a firearm.
FIG. 21 is a front bottom left perspective view of FIG. 20 showing the folding stacking unit attached to a vertical fore grip, with the stacking unit mounted to the firearm.
FIG. 22 is a rear top right perspective view of the folding stacking unit attached to fore grip, with the stacking unit mounted to a picatinny rail of a firearm of FIG. 20 .
FIG. 23 is front top left perspective view of the folding stacking unit attached to a vertical fore grip, with the stacking unit mounted to the firearm of FIG. 21 .
FIG. 24 is side view of bipod vertical fore grip detached from the stacking unit that is mounted beneath the firearm.
FIG. 25 is another side view of FIG. 24 with the fore grip mounted to the stacking unit.
FIG. 25A is an enlarged view of the fore grip mounted to stacking unit of FIG. 25 .
FIG. 26 is another view of FIGS. 24-25 with fore grip in folded position to firearm.
FIG. 26A is an enlarged view of the folded fore grip and mounting plate of FIG. 26 .
FIG. 27 is a side view of a foldable light/foldable fore grip with light detached from a stacking unit that is mounted beneath a firearm.
FIG. 28 is another view of FIG. 27 showing the light/fore grip with light, attached to the firearm mounted stacking unit, with light/fore grip with light, in folded position.
FIG. 29 is another view of FIGS. 27-28 with light/fore grip with light in downward extended position, with the light being useable as a map light, or the light being used as a vertical fore grip.
FIG. 30 shows a novel combined vertical fore grip with built in-light.
FIG. 31 is a side cross-sectional view of the interior of the fore grip light of FIG. 30 .
FIG. 32 is a front bottom perspective view of another embodiment of the folding stack adapter assembly with long clamp.
FIG. 33 is a rear bottom perspective view of the adapter assembly of FIG. 32 .
FIG. 34 is a front top perspective view of the adapter assembly of FIG. 32 .
FIG. 35 is a rear top perspective view of the adapter assembly of FIG. 32 .
FIG. 36 is a top view of the folding stack adapter assembly of FIG. 32 .
FIG. 37 is a side view of the folding stack adapter assembly of FIG. 32 .
FIG. 38 is a bottom view of the adapter assembly of FIG. 32 .
FIG. 39A is a left view of the adapter assembly of FIG. 32 .
FIG. 39B is an enlarged view of a portion of the adapter assembly of FIG. 39A showing radial slot cut in clamping apex to relieve mechanical clamping stress.
FIG. 39C is another radial slot cut in clamping apex to relieve mechanical clamping stress.
FIG. 40 is a right view of the adapter assembly of FIG. 32 .
FIG. 41 is a front top perspective view of the adapter assembly of FIG. 32 with a long clamp.
FIG. 42 is a front top perspective view of the adapter assembly of FIG. 32 with exploded long clamp.
FIG. 43 is a front top perspective view of adapter assembly with two short clamps.
FIG. 44 is a front top perspective view of the adapter assembly of FIG. 32 with exploded short clamps.
FIG. 45 is an exploded top front perspective view of the adapter assembly with long clamp.
FIG. 46 is an exploded top rear perspective view of the adapter assembly of FIG. 45 with long clamp.
FIG. 47 is an exploded bottom front perspective view of the adapter assembly of FIG. 45 with long clamp.
FIG. 48 is an exploded bottom rear perspective view of the adapter assembly of FIG. 45 with long clamp.
FIG. 49 is an end view of the adapter assembly of FIG. 45 with long clamp.
FIG. 49A is a cross-sectional view of the adapter assembly of FIG. 45 with pivot rail up.
FIG. 49B is an enlarged view of the thumb slide of FIG. 49A .
FIG. 49C is an enlarged view of the detent latch of FIG. 49B .
FIG. 50 is a side view of the adapter assembly.
FIG. 51 is a side view of the adapter assembly with swing plate down.
FIG. 51A is a cross-section view of the adapter assembly of FIG. 49A with pivot rail down.
FIG. 51B is another view of the thumb slide of FIG. 49B with pivot rail down.
FIG. 51C is another view of the detent latch of FIG. 49C with pivot rail down.
FIG. 52 is a side view w/pivot rail down.
FIG. 53 is a bottom front perspective view of the adapter assembly of the preceding figures with picatinny rail and foregrip with collapsible bipod legs.
FIG. 54 is a bottom rear perspective view of the adapter assembly with picatinny rail and foregrip with collapsible bipod legs of FIG. 53 .
FIG. 55 is a front top perspective view of the adapter assembly with picatinny rail and foregrip with collapsible bipod legs of FIG. 53 .
FIG. 56 is a front rear perspective view of the adapter assembly with picatinny rail and foregrip with collapsible bipod legs of FIG. 53 .
FIG. 57 shows the adapter assembly of the preceding figures locked to a guns picatinny rail separated from foregrip with collapsible bipod legs.
FIG. 58 shows the adapter assembly locked to the gun's picatinny rail of FIG. 57 for foregrip with collapsible legs.
FIG. 59 is another view of the adapter assembly swinging open on an unlatched pivot rail.
FIG. 60 is a bottom front perspective view of a folding rail assembly.
FIG. 61 is a bottom rear perspective view of the folding rail assembly of FIG. 60 with pivot rail down.
FIG. 62 is a top rear perspective view of the folding rail assembly of FIG. 61 with pivot rail down.
FIG. 63 is another top front perspective view of the folding rail assembly of FIG. 62 with pivot rail down.
FIG. 64 is a top view of the folding rail assembly of FIG. 60 .
FIG. 65 is a left view of the folding rail assembly of FIG. 60 .
FIG. 66 is a front view of the folding rail assembly of FIG. 60 .
FIG. 67 is a right view of the folding rail assembly of FIG. 60 .
FIG. 68 is a bottom view of the folding rail assembly of FIG. 60 .
FIG. 69 shows a folding rail assembly being used to replace stock picatinny rail supplied with a gun, and detached foreward grip with collapsible bipod legs.
FIG. 70 is another view of FIG. 69 with foreward grip having collapsible bipod legs connected to a locked folding rail assembly on gun.
FIG. 71 is another view of FIG. 70 with foreward grip having collapsible bipod legs attached to the folding rail assembly swinging open on unlatched pivot rail.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Before explaining the disclosed embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
The invention claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/905,556 filed Mar. 7, 2007, and this invention is a continuation in part of U.S. patent application Ser. No. 11/485,762 filed Jul. 13, 2006, which is a continuation in part of U.S. patent application Ser. No. 10/725,082 filed Dec. 2, 2003, now U.S. Pat. No. 7,111,424, and U.S. Design patent application Ser. No. 29/259,347 filed May 5, 2006, all by the same inventors and assigned to the same assignee, which are all incorporated by reference.
The inventors of the subject invention have to date patented at least one U.S. Pat. No. 7,111,424 to Gaddini, which is incorporated by reference. This patent includes a replaceable mounting assembly that allows for mounting of the gun handle by various means to a gun. A fore grip or gun handle, designed with ergonomic reasons in mind, provides a stable means of holding the gun. A plurality of legs that are concealed within the fore grip are coupled via a hinge to a spring piston assembly. A spring-loaded fulcrum release mechanism holds the piston assembly in a compressed and locked position.
When the piston assembly is released upon activation of the spring-loaded fulcrum release mechanism, the legs are driven downwards by the piston and upon being released from the confinement of the fore grip are deployed outwards to a locked position by a hinge or pivot mechanism. The legs have feet that are designed so that, when the legs are concealed within the handle, the feet seal off the deployment and spreader mechanisms from entrance of any debris, material etc that may interfere with the deployment of the bipod.
As shown in the figures, the invention can be used with the inventors novel fore grip that has a mounting section or end having parallel rails that can be attached to rails, such as picatinny rails on a firearm such as a rifle, and the like, by adjusting the head piece clamps with rail clamp bolt. The fore grip can include of a machining or a casting that utilizes aluminum or a molding that utilizes high impact resistant polymer or a composite material. The fore grip is a grip for gripping by the hand of a user when the fore grip is attached to the firearm.
Although the mounting end is shown as being an integral part of the handle for illustration purposes only, it should be understood that the mounting end head piece can be a separate component that is then attached by other members, such as threads or a lock screw or locking bolt to the handle. For illustrative purposes, the mounting end head piece uses a picatinny mounting rail (MIL-STD-1913 rail), a mounting system widely used by military for attachment of various devices to military rifles. However, it should be understood that other methods of attachment to a firearm could be used.
As described in the parent patent applications that are incorporated by reference, the fore grip can have a handle portion, with bottom retaining cap have a concealable and collapsible bipod legs. One version can have a tubular recess consisting of a first cylindrical cutout housing the bipod legs when concealed and a sliding piston that deploys the legs and a second cylindrical cutout housing a release mechanism and a void space for other accessories. The release mechanism such as a depressible button has a compression spring positioned between the piston assembly and the bottom of the first cylindrical cutout and the compression spring. The legs are connected to the bottom of the piston assembly via a hinge and spring that when released from confinement within the fore grip, causes the legs to expand outward until deployed.
Another version of the fore grip with bipod uses only one spring, wherein the legs can be gravity and/or snap/shook released from the handle by a switch (such as the depressible button) and the spring expands the legs out to the fully deployed position.
To use the fore grip, a user simply attaches the fore grip to the firearm, regardless of whether or not the bipod legs are deployed. If the legs are deployed, then the user has the option of using the gun with the legs deployed or compressing or squeezing the legs together, and pushing them upwards into the fore grip until the male part of the spring-loaded fulcrum release mechanism catches and locks the bipod legs and the piston assembly into the closed position.
As described above, the invention can be used with the inventors' novel bipod fore grip shown in the figures. A preferred embodiment can have the head piece having a length of approximately 1.85 inches a width of approximately 1.29 inches and a height of approximately 1.15 inches. In a fully leg retracted/closed position, the fore grip can have a height of approximately 6.32 inches. The handle portion 110 can have a length of approximately 2.95 inches and a width of approximately 1.37 inches. The legs can have a width of approximately 0.73 inches along with the feet having a width of approximately 0.99 inches. In a fully deployed/expanded position, the fore grip can have an overall height of approximately 8.57 inches, with the legs 120 having a spread eagle angle therebetween of approximately 76 degrees, and the inside angle of the feet 128 to the rest of the legs being approximately 52 degrees. The feet can be spread apart from toe to toe at approximately 6.95 inches.
Although, the preferred embodiment lists specific dimensions, the invention can be practiced with different sized and shaped components.
The fore grip can be made from various components such as but not limited to polymeric materials, such as but not limited to plastic and/or glass filled nylon with and without metal inserts such as aluminum, galvanized metal, stainless steel, and the like Additionally, the fore grip can include void spaces where possible to decrease weight.
Although a depressible button is shown above, the invention can use other types of activation such as but not limited to toggle switches, pressure actuated switches, temperature actuated switches and the like, to release the inside legs to slide down and expand outward from beneath the housing.
FOLDING STACKING PLATE DESIGNATOR REFERENCE NUMBERS
1000 Folding Stacking Unit
1004 Optional clamp turn screws to attach clamps
1006 Optional side plate for clamp turn screws
1010 Rail Mount Plate/top plate member
1012 leg member
1013 inwardly facing groove
1014 leg member
1015 inwardly facing groove
1018 notch on lower surface of top plate member
1019 pin-hole
1020 Pivot Rail Member/lower-bottom plate member
1022 Upper pivot rail edge
1024 Side Rail
1026 Side Rail
1028 front tab
1029 pin-hole
1030 Pivot Pin
1040 Release Button
1045 fastener (screw, and the like)
1050 Pivot Rail Latch
1052 Ledge edge of Latch
1055 Longitudinal Top Slot
1060 Release Button
1062 Finger Access Slot of Release button
1070 Latch Cover Plate
1074 Downwardly protruding pin
1075 fastener(s)
1075 R threaded receiving holes
1080 Picatinny Rail
1090 Vertical Fore Grip
1100 Latch Spring
1110 Latch Catch
1200 Firearm (i.e. rifle, etc.)
1400 Attachable/detachable light accessory/fore grip with light
1450 upper mounting plate with grooves
1455 fastening screw knob
1500 fore grip with built in light
1510 lens
1515 light source
1520 cap
1530 batteries
1550 inside of light fore grip
1590 depressible switch
1700 ) Adapter assembly with one long clamp.
1710 ) Adapter body.
1720 ) Swing plate.
1730 ) Pivot pin.
1740 ) Detent plate.
1750 ) Detent latch.
1760 ) Picatinny rail.
1770 ) Grip pod assembly.
1780 ) Adapter assembly with two short clamps.
1790 ) Gun.
1800 ) Folding rail assembly.
1810 ) Folding assembly swing plate.
1820 ) Thumb nut.
1830 ) Thumb slide.
1840 ) Plate latch.
1850 ) Long clamp.
1860 ) Set screw.
1870 ) Clamp screw.
1880 ) Short clamp A.
1890 ) Short clamp B.
1900 ) Radial stress relief slot.
1910 ) Slide spring.
1920 ) Detent spring.
1930 ) Folding rail body.
1940 ) Folding rail swing plate latch.
FIG. 1 is a bottom rear right perspective view of a folding stacking unit 1000 . FIG. 2 is a bottom front left perspective view of the stacking unit 1000 of FIG. 1 . FIG. 3 is a top rear right perspective view of the stacking unit 1000 of FIG. 1 . FIG. 4 is top front left perspective view of the stacking unit 1000 of FIG. 1 . FIG. 5 is a rear end view of the stacking unit 1000 of FIG. 1 . FIG. 6 is a left side view of the stacking unit 1000 of FIG. 1 . FIG. 7 is a front end view of the stacking unit 1000 of FIG. 1 . FIG. 8 is a top view of the stacking unit 1000 of FIG. 1 . FIG. 9 is a bottom view of the stacking unit 1000 of FIG. 1 .
Referring to FIGS. 1-10 , stacking unit 1000 can have a rail mount plate 1010 being a top plate member which hingedly attaches to a lower plate member 1020 which functions as a lower plate member by pivot pin 1030 . FIG. 10 is an exploded perspective view of the stacking unit 1000 of FIG. 1 . FIG. 11 is an exploded perspective view of the stacking unit 1000 of FIG. 1 .
Referring to FIGS. 1-11 , the stacking unit 1000 can include an upper surface with a pair of leg members 1012 , 1014 each with internal facing side grooves 1013 , 1015 . The grooves 1013 , 1015 are inwardly facing clamp edges that can slide about existing picatinny rails underneath of a firearm, such as a rifle and the like, which will be described in greater detail below. The inwardly facing clamp edges 1013 , 1015 can also include optional clamp turn screws 1004 ( FIG. 20 ) to attach the inwardly facing clamp edges about both sides of the existing picatinny rails underneath the firearm.
The stacking unit 1000 can also include a lower plate member 1020 (pivot rail) having opposite facing side rails 1024 , 1026 that can be similar to or replicate the existing picatinny rails underneath the firearm. The side rails 1024 , 1026 can be used for mounting a vertical fore grip such as the inventor's novel bipod fore grip thereon, which is shown below in FIG. 20 .
The lower member 1020 of the stacking unit 1000 can be pivotally mounted to the rail mount plate 1010 by a pivot pin 1030 that passes through pin-hole 1029 of the bottom plate member 1020 and pin-hole 1019 of top plate member 1010 . The fit can be a frictional fit where the operator pulling back on front tab 1028 can extend the pivot rail member (lower member) from a position horizontal to and within the top member (rail plate member) 1010 to a position substantially perpendicular to the rail mount plate member 1010 , where it is held in place by friction. Tab 1028 rests inside of notch 1018 on the lower surface of top plate member 1010 while lower plate member 1020 is perpendicular to top plate member 1010 .
FIG. 12 is an enlarged rear end view of the stacking unit 1000 of FIGS. 1 , 5 . FIG. 13 is an enlarged left side view of the stacking unit 1000 of FIGS. 1 , 6 . FIG. 14 is a cross-sectional view of the stacking unit 1000 of FIG. 12 along arrows 14 X.
FIG. 15 is a rear view of the preceding stacking unit 1000 with lower plate member 1020 (pivot rail member) folded forward. FIG. 16 is a left side view of FIG. 15 .
FIG. 17 is a cross-sectional view of FIG. 15 with pivot rail member 1020 folded forward. FIG. 17A is an enlarged view of the rail mount plate (top plate member) 1010 , release button 1060 , pivot rail latch 1050 , release button finger access slot 1060 and latch spring shown 1100 in FIG. 17 .
FIG. 18 is another cross-section view of FIGS. 15 , 17 with pivot rail member (lower plate member 1020 ) being folded. FIG. 18A is an enlarged view of the rail mount plate member (top plate member) 1010 , release button 1060 , pivot rail latch 1050 , release button finger access slot 1060 and latch spring 1100 shown in FIG. 18 .
FIG. 19 is another cross-section view of FIGS. 15 , 18 - 18 with pivot rail locked. FIG. 19A is an enlarged view of the rail mount plate, release button 1060 , pivot rail latch 1050 , release button finger access slot 1060 and latch spring 1100 shown in FIG. 19 .
Referring to FIGS. 12-18B , pushing the lower plate member (pivot rail member) 1020 in the opposite direction of CL allows the lower member 1020 to pivot back to latch and lock onto the rail mount plate 1010 which is shown in FIGS. 12-18B below.
As shown in FIGS. 10-11 , and 17 - 19 A, latch spring 1100 fits inside a top longitudinal slot 1055 within latch 1050 . An inner end of latch 1050 includes a ledge edge 1052 which can latch against upper ledge edge 1022 of pivot rail member 1020 (shown more clearly in FIGS. 17-19A . A release button 1040 can be held in place by a fastener 1045 such as a screw, and the like, which fastens into threaded surfaces in the end of pivot rail latch 1050 opposite to end having ledge edge 1052 .
A downwardly protruding pin 1074 in plate 1076 can fit into longitudinal top slot 1055 of pivot rail latch 1050 and be held in place by fasteners 1075 , such as screws which lock plate 1070 to threaded receiving holes 1075 R in top plate member 1010 .
The downwardly protruding pin 1074 is useful so that pivot rail latch 1050 can move to the left and right by the slot 1055 sliding about the downwardly protruding pin 1074 .
The operation of using the release button 1060 will know be described in reference to FIGS. 19A , 18 A, and 17 A in that order, the release button 1060 can be moved by the operator using a finger inserted into access slot 1062 of the release button 1060 to press against downwardly protruding lip edge 1042 in the direction of arrow R. Mount plate 1010 which is fixably attached to pivot rail latch 1050 contracts against latch spring 1100 while moving ledge edge 1052 away from upper pivot rail edge 1022 of pivot rail member 1020 . This allows the pivot rail member (lower plate member 1020 ) to be able to pivot downward to a vertical position as shown in FIG. 17 .
The pivotable lower plate member 1020 can have a pair of opposite facing rails that can mount to the inventors' bipod with extendable legs, which is shown and described in their previous patent, and other patents pending.
Alternatively, the stacking unit 1000 can allow for other fore grips to be mounted to thereon. Still furthermore, the stacking unit can be an integral part of a vertical fore grip.
While a pullout type switch is shown, the lower portion of the stacking unit can be released with other types of buttons, such as a depressible button, and the like.
FIG. 20 is a rear bottom right perspective view of the folding stacking unit 1000 attached to a vertical fore grip 1090 , with the stacking unit 1000 mounted to a picatinny rail 1080 of a firearm (not shown) such as a rifle, and the like. As previously described the clamp screw 1004 can be used to attach the folding stacking unit 1000 by holding an optional side plate 1006 in place.
FIG. 21 is a front bottom left perspective view of FIG. 20 showing the folding stacking unit 1000 attached to a vertical fore grip 1090 , with the stacking unit 1000 mounted to the picatinny rails 1080 of a firearm (not shown) such as a rifle, and the like. FIG. 22 is a rear top right perspective view of the folding stacking unit 1000 attached to fore grip 1090 , with the stacking unit 1000 is mounted to a picatinny rail 1080 of a firearm of FIG. 20 . FIG. 23 is front top left perspective view of the folding stacking unit 1000 attached to a vertical fore grip 1090 , with the stacking unit 1000 mounted to the firearm of FIG. 21 .
FIG. 24 is side view of bipod vertical fore grip 1090 detached from the stacking unit 1000 that is mounted beneath the firearm 1200 . As previously described, the clamping grooves of the stacking unit 1000 can mateably slide about the picatinny type rails 1080 under the firearm 1200 . Alternatively, the stacking unit 1000 can be attached to the picatinny rails by removing the optional side plate 1006 (shown in FIG. 20 ), by fasteners 1004 and positioning the remaining clamping groove about a picatinny rail and fastening the side plate 1006 back in place with fastener 1004 .
FIG. 25 is another side view of FIG. 24 with the fore grip 1090 mounted to the stacking unit 1000 . FIG. 25A is an enlarged view of the fore grip 1090 mounted to stacking unit 1000 of FIG. 25 .
FIG. 26 is another view of FIGS. 24-25 with fore grip in folded position to the firearm. FIG. 26A is an enlarged view of the folded fore grip 1090 and mounting plate 1000 with firearm 1200 of FIG. 26 .
Similar to the techniques for mounting the stacking unit 1000 to the firearm 1200 , the fore grip 1090 can be mounted by sliding the grooves on the top of the fore grip 1090 about the side rails 1024 , 1026 on the sides of the lower plate member (pivot rail member) 1020 . Alternatively, the side plates on the top of the fore grip 1090 can be removed and the fore grip 1090 attached to the side rails of the pivot rail member 1020 similar to the technique described above.
Referring to FIGS. 25 , 25 A, 26 and 26 A, pivot rail member 1020 with fore grip 1090 can be held in a horizontal orientation by a frictional fit. Alternatively, a pivotal lock catch 1120 which is pivotally attached to an undersurface portion of top plate member 1010 to one side of the fore grip 1090 has a pivotal arm with a notch end 1022 . Folding up fore grip 1090 in the direction of arrow F causes pivotal lock catch 1120 to rotate up so that rounded tip edges about notch 1022 push back spring biases spring pin 1135 in set screw 1130 until pin 1135 extends and catches into notch 1022 resulting in the fore grip 1090 being locked in a horizontal position. Pulling down on the bottom of fore grip 1090 can cause the other tip edge of pivotal lock catch 1120 to push against pin 1135 allowing the fore grip 1090 to go back to a vertical position.
Light Embodiments
FIG. 27 is a side view of a foldable light/foldable fore grip light 1400 detached from a stacking unit 1000 that is mounted beneath a firearm 1200 . FIG. 28 is another view of FIG. 27 showing the light/fore grip 1400 with light 1410 , attached to the firearm mounted stacking unit 1000 , with light/fore grip 1400 with light 1410 , in folded position. FIG. 29 is another view of FIGS. 27-28 with light/fore grip 1400 with light 1410 in downward extended position, with the light 1410 being useable as a map light, or the light being used as a vertical fore grip.
Referring to FIGS. 27-29 , the invention can have a novel light mounted to the stacking unit 1000 , so that the light can be used in either a folded position, or in a downwardly extending position. The light/fore grip 1400 with light 1410 can have an upper plate member assembly 1450 similar to dual inwardly facing grooves that exist on the top of the fore grip 1090 described above, with optional fastener 1455 , which can attach to the lower plate member 1120 similar to the previous embodiments above.
The folding unit can also allow the light to fold frontward, so that the light is turned on in the direction of where the firearm is pointed. Additionally, the folding unit can allow the light to face rearward behind the firearm. Additionally, the folding unit can allow the light to face sideways to the left and to the right of the firearm, as well.
Still furthermore, the invention can allow for both a vertical fore grip with a light built 1550 into the fore grip 1500 , so that it can have dual functions for use as a vertical fore grip and as light. The light can be useful for non firearm use, such as a map light to allow the operator to view maps, and the like, during dark conditions. FIG. 30 shows a novel combined vertical fore grip 1500 with built in-light. FIG. 31 is a side cross-sectional view of the interior of the fore grip light 1500 of FIG. 30 .
Referring to FIGS. 30-31 the fore grip 1500 can have a similar shape to the exterior surfaces of the fore grip 1090 previously described with an upper end 1505 being attachable to the lower plate member 1020 of stacking unit 1000 similar to the fore grip 1090 previously described. The inside 1550 of the fore grip 1500 can include components such as but not limited to batteries 1530 and a light source 1515 , such as a bulb, LED (light emitting diode), and the like, and lens 1510 . Cap 1520 can rotate to both turn on the light and allow the lens 1510 to extend beneath fore grip 1500 . Alternatively, side button 1590 can be depressed to active and deactivate light 1515 .
A list of components for additional embodiments will now be described. 1700 ) Adapter assembly with one long clamp.
1710 Adapter body.
1712 Front end
1713 Front horizontal slot
1715 Rear horizontal slot
1717 Longitudinal slot
1718 Rear end
1719 Cavity with mateable grooved interior walls
1720 Swing plate.
1722 . Side edges
1724 bottom of plate with raised flat ribs (four shown)
1725 hinge end
1726 top of plate with raised rounded ribs (two shown)
1727 groove in rounded surface of hinge end 1725
1728 outer ledge catch end
1730 Pivot pin.
1740 Detent plate.
1745 Screw type fasteners
1750 Detent latch.
1752 U-shaped slot
1758 Protruding end
1760 Picatinny rail.
1770 Grip pod assembly.
1780 Adapter assembly with two short clamps.
1790 Gun.
1800 Folding rail assembly.
1810 Folding assembly swing plate.
1815 . Hinge
1820 Thumb nuts.
1830 Thumb slide.
1835 Screw type fastener
1840 Plate latch.
1842 Raise side edges of plate latch
1844 Rear end of latch
1845 . Slot in latch
1848 Protruding end
1850 Long clamp.
1860 Set screw.
1870 Clamp screws.
1875 Threaded ends.
1880 Short clamp A.
1890 Short clamp B.
1900 Radial stress relief slot.
1910 Slide spring.
1920 Detent spring.
1930 Folding rail body.
1932 . Forward End
1933 . opening
1935 . Base
1937 . opening
1938 rearward end
1940 Folding rail swing plate latch.
1942 . Rotatable Knob
1945 Protruding edge
Adapter Assembly with One Long Clamp
FIG. 32 is a front bottom perspective view of another embodiment of the folding stack adapter assembly 1700 with long clamp. FIG. 33 is a rear bottom perspective view of the adapter assembly 1700 of FIG. 32 . FIG. 34 is a front top perspective view of the adapter assembly of FIG. 32 . FIG. 35 is a rear top perspective view of the adapter assembly 1700 of FIG. 32 . FIG. 36 is a top view of the folding stack adapter assembly 1700 of FIG. 32 . FIG. 37 is a side view of the folding stack adapter assembly 1700 of FIG. 32 . FIG. 38 is a bottom view of the adapter assembly 1700 of FIG. 32 . FIG. 39A is a left view of the adapter assembly 1700 of FIG. 32 . FIG. 39B is an enlarged view of a portion of the adapter assembly 1700 of FIG. 39A showing radial slot cut in clamping apex to relieve mechanical clamping stress. FIG. 39C is another radial slot cut in clamping apex to relieve mechanical clamping stress. FIG. 40 is a right view of the adapter assembly 1700 of FIG. 32 . FIG. 41 is a front top perspective view of the adapter assembly 1700 of FIG. 32 with a long clamp 1850 . FIG. 42 is a front top perspective view of the adapter assembly 1700 of FIG. 32 with exploded long clamp 1850 .
FIG. 45 is an exploded top front perspective view of the adapter assembly with long clamp. FIG. 46 is an exploded top rear perspective view of the adapter assembly of FIG. 45 with long clamp. FIG. 47 is an exploded bottom front perspective view of the adapter assembly of FIG. 45 with long clamp. FIG. 48 is an exploded bottom rear perspective view of the adapter assembly of FIG. 45 with long clamp 1850 . FIG. 49 is an end view of the adapter assembly of FIG. 45 with long clamp 1850 . FIG. 49A is a cross-sectional view of the adapter assembly of FIG. 45 with pivot rail up.
FIG. 49B is an enlarged view of the thumb slide of FIG. 49A . FIG. 49C is an enlarged view of the detent latch of FIG. 49B . FIG. 50 is a side view of the adapter assembly. FIG. 51 is a side view of the adapter assembly with swing plate down. FIG. 51A is a cross-section view of the adapter assembly of FIG. 49A with pivot rail down. FIG. 51B is another view of the thumb slide of FIG. 49B with pivot rail down. FIG. 51C is another view of the detent latch of FIG. 49C with pivot rail plate 1720 down. FIG. 52 is a side view w/pivot rail plate 1720 down.
Referring to FIGS. 32-52 , an adapter assembly with one long clamp 1700 can include a rectangular adapter body 1710 having a plate type configuration. Located on the bottom the adapter assembly body 1710 can be swing plate 1720 with side edges 1722 similar to the edges of a picatinny rails (shown as 1760 in FIG. 53 ) that are often attached underneath of a weapon. The pivoting plate 1720 can be located between the front end 1712 and rear end 1718 of the adapter body 1710 . The plate 1720 can have a bottom side 1724 with raised flat ribs, and an upper top side 1726 with raised rounded ribs. One end 1725 of the plate 1720 can be pivotally attached by a pivot pin 1730 to a front end 1712 of the adapter body 1710 (see FIG. 51A ).
Detent Plate in Front End
In the front end 1712 of the adapter body 1710 can be detente plate 1740 which holds a detent spring 1920 on inner side. See for example, FIGS. 32 , 34 , 39 A, 41 - 45 , 47 , 48 , 49 C, 51 C. The detent plate 1740 can be a fixably attached to the front end 1712 of the adapter body 1710 by screw type fasteners 1745 . The detent spring 1920 pushes into a U-shaped slot 1752 of the detent latch 1750 . The opposite protruding end 1758 is biased toward and against the pivot hinge 1725 . The rounded exterior surface of the pivot hinge 1725 allows for the rail plate 1720 to easily rotate downward until the protruding end 1758 locks into groove 1727 in the exterior surface 1725 of the swing plate 1720 so that the pivoting plate 1720 is locked in a substantially vertical orientation relative to the adapter body 1710 . (See FIGS. 49A , 49 C, 51 A, 51 C).
To rotate the pivoting plate 1720 back to a horizontal position, the user can press against the pivoting plate, often by grabbing the accessory clamped to the plate such as the foregrip to overcome the spring tension 1920 of the detent plate 1740 .
Thumb Slide in Rear End
In the rear end 1718 of the adapter body 1710 can be a thumb slide 1830 . See for, example, FIGS. 32 , 33 , 35 , 37 , 38 , 40 , 45 , 46 , 47 , 48 . The thumb slide 1830 can have a raised angled surface and be attached to a slot 1845 in plate latch 1840 by a screw type fastener 1835 (See FIGS. 45 , 47 , 48 ). The plate latch 1840 can have raised side edges 1842 form a dovetail shape that allows the plate latch 1840 to slide within a matching grooves inside of dovetail shaped cavity 1719 in rear end 1718 of the adapter body 1710 . A longitudinal slot 1717 along the longitudinal axis of the rear end 1718 allows for the thumb slide 1830 to slide relative to the rear end 1718 . (See FIGS. 45 , 47 , 48 ).
The freely moving protruding end 1848 of the plate latch 1840 when pushed by the thumb slide 1830 in the direction of arrow X 1 can latch onto and catch the outer ledge catch step-shaped end 1728 of the freely moving end of the swing plate 1720 . The upper surface of the protruding end 1848 can be sloped at an angle so as to lift against the catch step-shaped end 1728 of the swing plate 1720 . The spring 1910 pushes the sloped surface of protruding end 1848 so that it takes up any play between itself and the catch step-shaped end 1728 . This play can exist based due to manufacturing tolerances and/or regular wear of these parts. See for example, FIGS. 49A , 49 B, 51 A, 51 B.
The rear end 1844 of the plate latch 1840 can push against a slide spring 1910 and the length adjustable set screw 1860 so that the protruding end 1848 of the plate latch 1840 is being pushed in the direction of arrow X 1 . The spring is sandwiched between the set screw 1860 and the rear end 1844 of the plate latch 1840 . By not fully seating the screw 1860 against the spring 1910 , the tension of the spring 1910 can be adjusted. Tightening the length adjustable set screw 1860 can further lock the protruding end 1848 of the plate latch against the outer ledge catch end 1728 of the swing plate 1720 . Loosening the set screw 1860 can allow for the thumb slide 1830 to more easily slide in place. The user can release the swing plate 1720 from a horizontal position and rotate in the direction of arrow R, by pushing the thumb slide 1830 in the direction of arrow X 2 , shown in FIGS. 51 , 51 A, 51 B, 52 .
A pair of clamp screws 1870 can pass through horizontal slots ( 1713 in the front end, and horizontal slot 1715 in the rear end 1718 of the adapter body 1710 . See for example, FIGS. 39A , 39 B, 39 C, 40 , 45 - 48 . The threaded ends 1875 of the clamp screws 1870 are held against the long clamp 1850 by respective thumb nuts 1820 . A radial stress relief slot 1900 can be formed between the long clamp 1850 side and the opposite side of the adapter body 1710 . The radial stress relief slot 1900 has interior facing groove side walls that allow for the adapter assembly to wrapped about picatinny rails underneath of a weapon. A user can loosen the thumb nuts 1820 to allow the adapter assembly 1700 to slide about the picatinny rails 1760 underneath a weapon 1790 , such as a gun.
FIG. 53 is a bottom front perspective view of the adapter assembly 1700 of the preceding figures with picatinny rail 1760 and foregrip 1770 with collapsible bipod legs. Such a foregrip with collapsible bipod legs can include ones such as those shown and described in U.S. Pat. Nos. D566,219; 7,111,424; 7,409,791; and 7,490,429 to the same assignees of the subject invention, and which are all incorporated by reference.
FIG. 54 is a bottom rear perspective view of the adapter assembly 1700 attached to a picatinny rail 1760 , where the adapter assembly 1700 is attached to a foregrip 1770 with collapsible bipod legs of FIG. 53 . FIG. 55 is a front top perspective view of the adapter assembly 1700 with picatinny rail 1760 attached to a foregrip 1770 with collapsible bipod legs of FIG. 53 . FIG. 56 is a front rear perspective view of the adapter assembly 1700 attached to picatinny rails 1760 , with the adapter assembly 1700 attached to the upper end of a foregrip 1770 with collapsible bipod legs of FIG. 53 . FIG. 57 shows the adapter assembly 1700 of the preceding figures locked to a gun's picatinny rail 1760 separated from the foregrip 1770 with collapsible bipod legs. FIG. 58 shows the adapter assembly 1700 locked to the gun's picatinny rail 1760 of FIG. 57 with the adapter assembly 1700 attached to the foregrip 1770 with collapsible legs. FIG. 59 is another view of the adapter assembly 1700 with swing plate 1720 swinging open to an unlatched position.
Adapter Assembly with Two Short Clamps
FIG. 43 is a front top perspective view of adapter assembly 1780 with two short clamps 1880 , 1890 . FIG. 44 is a front top perspective view of the adapter assembly 1780 of FIG. 32 with exploded short clamps 1880 , 1890 . Unlike the previous embodiment, the adapter assembly 1780 has two short clamps 1880 , 1890 instead of long clamp 1850 . Other than the short clamps 1880 , 1890 , this embodiment functions similarly to the previous embodiment with long clamp 1850 . A radial stress relief slot 1900 is formed between the pair of short clamps 1880 , 1890 and opposite side of the adapter body 1710 . The two clamps 1880 , 1990 together have less weight and less material and be less costly than a single long clamp 1850 . Reducing weight of the invention can be desirable in the field where soldiers desire the least amount of weight for their equipment. The single long clamp 1850 can be more stable when attaching about picatinny rails underneath of a firearm.
Folding Rail Assembly
FIG. 60 is a bottom front perspective view of a folding rail assembly 1800 . FIG. 61 is a bottom rear perspective view of the folding rail assembly 1800 of FIG. 60 with pivot rail 1810 down. FIG. 62 is a top rear perspective view of the folding rail assembly 1800 of FIG. 61 with pivot rail 1810 down. FIG. 63 is another top front perspective view of the folding rail assembly 1800 of FIG. 62 with pivot rail 1810 down. FIG. 64 is a top view of the folding rail assembly 1800 of FIG. 60 . FIG. 65 is a left view of the folding rail assembly 1800 of FIG. 60 . FIG. 66 is a front view of the folding rail assembly 1800 of FIG. 60 . FIG. 67 is a right view of the folding rail assembly 1800 of FIG. 60 . FIG. 68 is a bottom view of the folding rail assembly 1800 of FIG. 60 .
Referring to FIGS. 60-68 , the folding rail assembly 1800 includes a folding rail body 1930 having a generally planar plate configuration with a foreward end 1932 and a rearward end 1938 , each having openings 1933 , 1937 for allowing fasteners such as screws and bolts to attach the assembly 1800 to an undersurface of a weapon. In a preferred embodiment both the forward end 1932 and the rearward end 1937 have picatinny type side rails on both sides. In the middle of the assembly 1800 between the forward end 1932 and the rearward end 1937 can be pivotal swing plate 1810 also having picatinny type rails on both sides. A hinge 1815 attaches on end of the swing plate 1810 to the forward end 1932 . A swing plate latch 1940 can be on the rearward end 1938 of the rail assembly 1800 . The latch 1940 can be rotatable by a raised knob 1942 that allows for an extended portion 1945 to be over the free end 1812 of the swing plate 1810 .
On the top of the rail assembly 1800 can be a longitudinal base 1935 having a generally flat surface for allowing the rail assembly to sit flush against the undersurface of a firearm.
FIG. 69 shows a folding rail assembly 1800 being used to replace stock picatinny rail that is often supplied with a gun 1790 , and detached foreward grip 1770 with collapsible bipod legs. FIG. 70 is another view of FIG. 69 with foreward grip having collapsible bipod legs connected to a locked folding rail assembly on gun 1790 . FIG. 71 is another view of FIG. 70 with foreward grip 1770 having collapsible bipod legs attached to the folding rail assembly 1800 swinging open on an unlatched pivot rail.
The folding rail assembly 1800 can be a substitute for the picatinny rails that are often attached underneath of firearm. The folding rail assembly can be used underneath the gun or in other areas, such as but not limited to be attached to one side of the gun or on top of the gun.
The folding rail assembly 1800 has a lower profile than the folding stack embodiments that were previously described. The folding rail assembly 1800 would allow for accessories such as a foregrip to be located closer to the weapon, instead of being spaced away from the weapon. A problem with foregrips is that the lower end of a vertical foregrip can extend further than what is desired. For example the lower bottoms of foregrips have been known to catch on the ground, etc., and/or poke into the user.
The folding rail assembly 1800 is more ergonomic than a folding stack assembly since it does not lengthen the overall length of a foregrip that can be attached thereon.
The folding rail assembly 1800 would be similar in weight to an existing picatinny rail system The folding rail assembly 1800 would have substantially less weight and use less material and be less expensive than the folding stack embodiments.
Similar to the previous embodiments, the folding rail can be modified to lock in both the horizontal and vertical positions, using features similar to that of the previous embodiments.
Although the invention mentions a plate, the invention can include different shapes, such as but not limited to oblong shapes, rectangular shapes, cylindrical shapes, and the like.
While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended. | Adapter devices, apparatus, systems and methods of allowing a firearm to be supported by a foldable fore grip/gun handle. The fore grip gun handle can have bipod type legs that can be extendable from the handle. The fore grip handle can be just a vertical extension. The adapter can allow for the fore grip/gun handle to move from a fold back position along the bottom of the firearm so that the firearm can be easily carried, and the adapter to can allow for the handle to move down to a vertical support position beneath the firearm when the firearm is to be used. The adapter can also support a light in both a folded position and in a downwardly extended position, where light can be aimed forward, rearward to the side and/or pointed down from the firearm. The adapter can allow for a dual functioning component that can be either or both a fore grip and/or a light source. Other versions of the adapter can include a slidable thumb switch for locking a swinging plate with picatinny side rails to a main plate, and spring loaded detents for locking the swinging plate in substantially vertical orientations. Additionally, a folding rail system can be substituted for the existing picatinny rail system on firearms. The folding rail can have mounting holes for allowing the entire folding rail to be directly attached to the firearm, and have a hinge for allowing portions of the picatinny rails to pivot relative to the rest of the picatinny rails. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional patent application Ser. No. 60/062,078, filed Oct. 15, 1997.
BACKGROUND OF THE INVENTION
This invention relates to testing circuitry, and more particularly to methods and apparatus for facilitating the scan testing of such circuitry.
Scan testing is a well-known technique for testing circuitry to determine whether or not the circuitry has been properly designed to function as required under all operating conditions, and also to determine whether the circuit itself has been fabricated properly and without defects. In some designs, scan registers are added in addition to the actual logic registers to implement the scan chain. For those designs, the actual logic registers are not used in the scan chain and are thus not affected.
In other cases, the logic registers, themselves, are used for scanning out data. In this case, the logic registers serve as logic registers in normal operation. However, during scan testing, these same registers are used to shift their stored values along the scan chain. This latter case reduces hardware in the circuit because dedicated scan registers do not need to be added.
As a consequence of using the same registers for both normal operation and scan testing, the output of these registers toggles with scan data during the scanout procedure. If these same outputs drive bistable circuits (e.g., J-K flip-flops), the toggling of the register output could change the state of the bistable. Therefore, even if the scan register data is scanned back into the device, the original state of the machine is lost. It is because of the loss of state that this type of scanout is destructive. Therefore, using the prior art technique, it is not possible to stop a circuit, scan out its register contents, and then continue on where the circuit was stopped. Instead, the circuit has to be re-initialized and its input pattern rerun.
In view of the foregoing, it is an object of this invention to provide improved methods and apparatus for scan testing circuits.
It is another object of this invention to make it possible for normal operation of a circuit to be stopped, to have the data scanned out, and then to have the original state recovered so that the circuit can continue running from the point just before scan testing began.
SUMMARY OF THE INVENTION
These and other objects of the invention are accomplished by providing circuitry having register circuits, each having an input gate configured to selectively pass a data signal applied to that register, and a master stage configured to store a data signal passed by the input gate of that register. Each register circuit has an interstage gate configured to selectively pass a data signal stored by the master stage of that register, and a slave stage configured to store a data signal passed by the interstage gate of that register. Inter-register gates are operatively arranged to selectively pass a data signal stored by the master stage of an associated respective first one of the registers to the master stage of an associated respective second one of the registers for storage by the master stage of that second one of the registers. The master stages of all of the registers and the inter-register gates are connected in a series of alternating master stages and inter-register gates.
Normal mode circuitry is configured to alternately enable the input gates and the interstage gates of each register. This enables the contents of each master stage to be stored by the associated slave stage. Normal mode circuitry also disables the inter-register gates, which are not used during normal operation. Scan mode circuitry is configured to disable the input gates and the interstage gates to preserve the outputs of all register slave stages of the circuit during scanout. Alternate ones of the inter-register gates are enabled by the scan mode circuitry.
In a preferred embodiment, a feedback gate is configured to selectively pass a data signal stored by the slave stage of each of the registers to the master stage of that register for storage by that master stage. The scan mode circuitry is further configured to enable the feedback gates while disabling the input gates, the interstage gates, and the inter-register gates. In a preferred embodiment, restoration mode circuitry is configured to selectively enable one of the input gates and the feedback gates and to disable the interstage gates and the inter-register gates. The selection between the input gates and the feedback gates may be based on the phase of a clock signal.
Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram of a representative portion of circuitry including elements in accordance with this invention for facilitating scan testing of that circuitry.
FIG. 2 a is a time plot of a control signal sequence in accordance with the invention.
FIG. 2 b is a time plot of another control signal sequence in accordance with the invention.
FIG. 2 c is a time plot of yet another control signal sequence in accordance with the invention.
FIG. 2 d is a time plot of an additional control signal sequence in accordance with the invention.
FIG. 2 e is a time plot of another control signal sequence in accordance with the invention.
FIG. 3 is a schematic block diagram of a representative portion of circuitry in accordance with another embodiment of the subject invention.
FIG. 4 is a schematic block diagram illustrating another portion of the embodiment of FIG. 3 .
FIG. 5 a is a time plot of a control signal sequence in a first logical state in accordance with the embodiments of FIGS. 3-4.
FIG. 5 b is a time plot of another control signal sequence in accordance the invention.
FIG. 5 c is a time plot of yet another control signal sequence in accordance with the invention.
FIG. 5 d is a time plot of an additional control signal sequence in accordance with the invention.
FIG. 5 e is a time plot of a fifth control signal sequence in accordance with the invention.
FIG. 5 f is a time plot of a sixth control signal sequence in accordance with the invention.
FIG. 5 g is a time plot of a seventh control signal sequence in accordance with the invention.
FIG. 5 h is a time plot of a eighth control signal sequence in accordance with the invention.
FIG. 5 i is a time plot of a ninth control signal sequence in accordance with the invention.
FIG. 6 a is a time plot of a control signal sequence in a second logical state in accordance with the embodiments of FIGS. 3-4.
FIG. 6 b is a time plot of another control signal sequence in accordance the invention.
FIG. 6 c is a time plot of yet another control signal sequence in accordance with the invention.
FIG. 6 d is a time plot of an additional control signal sequence in accordance with the invention.
FIG. 6 e is a time plot of a fifth control signal sequence in accordance with the invention.
FIG. 6 f is a time plot of a sixth control signal sequence in accordance with the invention.
FIG. 6 g is a time plot of a seventh control signal sequence in accordance with the invention.
FIG. 6 h is a time plot of a eighth control signal sequence in accordance with the invention.
FIG. 6 i is a time plot of a ninth control signal sequence in accordance with the invention.
FIG. 7 is a simplified block diagram of an illustrative system employing a circuit in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a circuit schematic in accordance with the present invention. In the description which follows, reference is made to “normal operation”, which refers to the mode of operation for which the circuit was designed. “Scanout” or “scan” will refer to the test mode in which normal operation is suspended to enable the detection of the states of logical elements (especially registers, i.e., flip-flops) within the circuit.
The circuit elements shown may represent a portion of an integrated digital circuit containing several circuit elements. Four register circuits, i.e., flip-flops 20 - 1 , 21 - 1 , 20 - 2 and 21 - 2 have been represented in the FIG., although it is contemplated that any number of register circuits may be used depending upon the application. (Reference numbers 20 and 21 are used for convenience in the description below, although flip-flops 20 and flip-flops 21 are all substantially identical.) Each of flip-flops 20 / 21 is part of the normal logic of circuitry 10 which is to be tested, generally along with other normal logic (not shown) which generates the data signals 16 - 1 through 16 -n normally applied to the data input terminals of flip-flops 20 / 21 , and/or which uses the registered output signals 30 - 1 through 30 -n of those flip-flops.
In the embodiment shown in FIG. 1, the flip-flops are rising-edge triggered. Each flip-flop contains a master stage 22 / 23 , followed by a slave stage 24 . An input pass gate 26 is provided at the input to each master stage 22 / 23 , and an interstage pass gate 28 is provided between each master stage 22 / 23 and the associated slave stage 24 . (As with flip-flops 20 / 21 above, master stages 22 and master stages 23 are substantially identical. For purposes of the description, master stages 22 are associated with flip-flops 20 , and master stages 23 are associated with flip-flops 21 .)
A global clock signal GCLK 12 - 1 is provided to the circuit and regulates the function of pass gates 26 and 28 . GCLK 12 - 1 is fed to each pass gate 28 and serves as the first of the two inputs to each NOR gate 32 . During normal operation, the second input SCANOUT 12 - 2 is low. (SCANOUT, which initiates the scan procedure, will be described in greater detail below.) The NOR gate thus functions effectively as an inverter to GCLK 12 - 1 . The output of each NOR gate 32 is fed to each pass gate 26 . Consequently, the GCLK-related signals to pass gates 26 and 28 are of different polarity during normal operation. If pass gate 26 is enabled by the inverted GCLK signal, then pass gate 28 is disabled by the non-inverted GCLK signal. Conversely, when pass gate 26 is disabled by the inverted GCLK signal, pass gate 28 is enabled by the non-inverted GCLK signal, i.e., pass gates 26 and 28 are alternately enabled. This makes possible the initial reception of input 16 by each master stage 22 / 23 , and the subsequent transfer of the state of master stage 22 / 23 to the associated slave stage 24 after GCLK 12 - 1 is toggled.
The global signal SCANOUT 12 - 2 is used to initiate the scanout mode, during which mode GCLK is held low. During the non-destructive scanout process, SCANOUT 12 - 2 is high. Consequently, when SCANOUT is high, all pass gates 26 are disabled because the SCANOUT signal is fed into each NOR gate 32 , as described above. The outputs from any elements on 16 - 1 through 16 -n are thereby cut off and not passed on to flip-flops 20 / 21 .
Additional structure is provided to facilitate the non-destructive scanout process. An inter-register pass gate 34 / 36 is provided between master stages of adjacent flip-flops 20 / 21 . More particularly, a scan chain is formed as a series of master stages and pass gates 34 alternating with pass gates 36 between adjacent master stages. Pass gates 34 and 36 may be a CMOS pass gate, or an NMOS transistor, or equivalent structure known in the art. As FIG. 1 illustrates, pass gates 34 are activated by clocking signal SCANCLKB 12 - 3 , while pass gates 36 are activated by clocking signal SCANCLKA 12 - 4 . This permits master stages 22 / 23 to be coupled in pairs, as will be described in greater detail below.
Clocking signal SCANCLKB 12 - 3 is derived from SCANCLKA 12 - 4 and a second global signal SCANCLKBEN 125 . SCANCLKBEN 12 - 5 is inverted, and along with SCANCLKA 12 - 4 , serves as the two inputs to NOR gate 38 . Thus, when SCANCLKBEN 12 - 5 is low, SCANCLKB will be low also. When SCANCLKBEN is high, SCANCLKA and SCANCLKB will be of opposite polarity.
When it is desired to enter the scan mode, GCLK is held low, and SCANOUT is held high. Register data may then be read out by coupling the master stages of adjacent flip-flops 20 / 21 with inter-register gates 34 / 36 . The coupling process is achieved by alternately enabling and disabling pass gates 34 and 36 in response to SCANCLKA and SCANCLKB. First, the contents of master stages 22 of the flip-flops 20 of each coupled pair are passed down to the scan output at the bottom of the chain to SCAN DATA OUT 40 . The original state of each of the flip-flops 20 / 21 may then be restored by enabling the pass gate 26 associated with each master stage 22 / 23 . This is achieved by toggling the SCANOUT signal 12 - 2 to the low logical state, or condition. Subsequently, SCANOUT is returned to high and adjacent flip-flops are re-coupled such that each flip-flop 21 is now the first of each pair, and the contents of the master stages 23 of flip-flops 21 are scanned out, as will be described in greater detail below.
Lastly, the original state of each of the flip-flops 20 / 21 can be restored again by toggling the SCANOUT signal 12 - 2 to the low condition, thereby enabling the pass gate 26 associated with each master stage 22 / 23 . Normal operation of the circuit can then be resumed.
In the foregoing discussion, the original states of flip-flops 20 / 21 are restored each time pass gates 26 are enabled because all inputs to circuit 10 (other than the scan control signals) are assumed to be held constant during the scan process, and because the contents of the slave stages 24 of all flip-flops in circuit 10 are undisturbed by the scan process (pass gates 28 all being disabled during the scan process). Thus, no matter what the source of each of inputs 16 (i.e., whether an input 16 is derived from one or more inputs to circuit 10 and/or from one or more flip-flop outputs 30 in circuit 10 ), each input 16 remains constant throughout the scan process and available to restore the master stage of the associated flip-flop 20 / 21 to its pre-scan state whenever pass gates 26 are enabled.
Operation of the Apparatus
The non-destructive scan procedure will now be described in greater detail with respect to an illustrative sequence of timing signals illustrated in FIGS. 2 a - 2 e , in conjunction with FIG. 1 . It is contemplated that other timing sequences may be performed to conduct the scan procedure. FIGS. 2 a - 2 e are aligned such that signals represented in the FIGS. in the same horizontal position occur simultaneously. The duration of the various clock pulses and signals are not shown to scale and may have whatever duration is deemed appropriate to one skilled in the art.
Normal operation is indicated in stage I of FIGS. 2 a - 2 e . During normal operation, the global clock function is supplied by GCLK 12 - 1 . Flip-flops 20 / 21 operate with the adjoining circuit elements as normal. Furthermore, SCANOUT 12 - 2 is low (FIG. 2 b ). As a result, NOR gates 32 operate as inverters on the GCLK signal. The SCANCLKBEN (FIG. 2 d ) and SCANCLKA (FIG. 2 c ) signals are also low. Consequently, the pass gates 34 and 36 between adjacent master stages are disabled.
The initiation of scan testing is represented at stage II of FIGS. 2 a - 2 e . GCLK is low such that normal operation is suspended. SCANOUT 12 - 2 is toggled to the high condition at time t 1 (FIG. 2 b ). Consequently, both pass gates 26 and 28 are disabled for all flip-flops 20 / 21 . As long as all the master and slave latches are disabled, the outputs 30 of all registers 20 / 21 remain static, and as a result the inputs 16 to all registers will remain static (again assuming that all inputs to circuit 10 (other than scan control inputs) are held constant).
Subsequently, the scanout procedure for flip-flops 20 - 1 through 20 -n is commenced as indicated in stage III of FIGS. 2 a - 2 e . During this stage two adjacent flop-flips 20 / 21 form a pair in order to scan data from the first flip-flop 20 of each pair down to the bottom of the chain. As shown in the FIGS., this process is initiated by toggling SCANCLKA high, starting at time t 2 (FIG. 2 c ) before SCANCLKBEN is toggled to the high condition. As a result, the state of master stage 22 of the first flip-flop 20 of each pair is passed to the master stage 23 of the second flip-flop 21 of the pair. Thus, the contents of the master stage 23 of each flip-flop 21 is overwritten by the master stage 22 of each flip-flop 20 . In effect, master stage 23 of flip-flop 21 temporarily acts as a slave stage to master stage 22 of flip-flop 20 .
As indicated in stage III of FIGS. 2 a - 2 e , SCANCLKA is toggled while SCANCLKBEN remains high. As SCANCLKA is toggled, data from flip-flops 20 is passed vertically downward. This data may be scanned out (via element 40 ) at the bottom of the chain (see FIG. 1 ).
The next step in the non-destructive scanout procedure is the recovery of the initial state as illustrated in stage IV in FIGS. 2 a - 2 e . Global clock GCLK remains low during this stage (FIG. 2 a ). Since no data is being scanned out, SCANCLKA and SCANCLKBEN are both low. SCANOUT is toggled from high to low at time t 3 (FIG. 2 b ). Deasserting SCANOUT enables all pass gates 26 to be enabled. Consequently, the initial state of all master stages 22 / 23 is recovered.
The scanout procedure for flip-flops 21 - 1 through 21 -n is now initiated as indicated in stage V of FIGS. 2 a - 2 e . During this stage, flip-flops 20 / 21 are again paired. However, master stage 22 of each flip-flop 20 temporarily acts as a slave stage to master stage 23 of each flip-flop 21 to permit scanning of data from the master stages 23 of flip-flops 21 . SCANOUT is toggled back from low to high to disable pass gates 26 at time t 4 (FIG. 2 b ).
To begin scanout at stage VI, SCANCLKBEN is asserted at time t 5 before SCANCLKA (FIG. 2 d ), in contrast with scanout at stage III, described above. As a result, data in the master stage 23 of each first flip-flop 21 in the pair of flip-flops 20 / 21 is passed to the master stage 22 of the second flip-flop 20 of the pair. Thus, the contents of the master stage 22 of flip-flop 20 are overwritten by the master stage 23 of flip-flop 21 . As in stage III, described above, SCANCLKA is toggled while SCANCLKBEN remains high. As SCANCLKA is toggled, data from flip-flops 21 is passed vertically downward. This data may be scanned out at the bottom of the chain.
The recovery stage, again referred to as stage IV in FIGS. 2 a - 2 e , recovers the initial state of the machine during normal operation in stage I prior to commencement of the scanout process. Once the data from flip-flops 21 have been scanned out, SCANCLKA and SCANCLKBEN remain in the low condition. The initial state is recovered by toggling SCANOUT from the high to the low condition at time t 6 (FIG. 2 b ). Consequently, pass gates 26 are re-enabled. Once the initial state is recovered, the normal operation (stage I) may continue, as indicated by the resumption of the global clock GCLK signal at time t 7 (FIG. 2 a ).
A Second Embodiment of the Apparatus and Method
FIGS. 3-4 illustrate another embodiment in accordance with the subject invention. This embodiment is substantially identical to the circuitry disclosed above with respect to FIG. 1, with the differences described below. As with the circuitry described above, the embodiment of FIGS. 3-4 permits the scan testing of logical elements within the circuit, and the subsequent restoration of the states of these elements so that normal operation may resume without re-initialization. It is contemplated that the invention may be used with both rising-edge activated and trailing-edge activated flip-flops. The invention provides the ability to restore the states of the flip-flops, regardless of the phase of the clock when normal operation was suspended. The clock signal, as will be described for the exemplary embodiment, corresponds to signal 212 .
As illustrated in FIG. 3, each flip-flop 120 / 121 includes a master stage 122 / 123 and a slave stage 124 . During normal operation, the master stage receives data signals from the circuitry as inputs. Thereafter, the contents of the slave stage are overwritten with the contents of the master stage. Normal operation is suspended to initiate the scanout procedure. Depending upon the polarity of the clock signal when normal operation is stopped, the slave stage may or may not have yet been over-written. Therefore, the process of restoring the state of the flip-flop will vary according to the polarity of the clock signal at which normal operation was suspended. Accordingly, flip-flops 120 / 121 as illustrated in FIG. 3 are structured so that the state of each master stage may be restored regardless of when normal operation was suspended. Thus, the master stage may be restored from the input 16 -n to the master stage, which is substantially similar to the restoration process described above with respect to FIGS. 2 a - 2 e . Alternatively, restoration may occur from the slave stage itself, as will be described in greater detail below.
The circuit elements shown in FIG. 3 may represent a portion of an integrated digital circuit containing several circuit elements. Four flip-flops 120 - 1 , 121 - 1 , 120 - 2 and 121 - 2 have been represented in the FIG., although it is contemplated that any number of flip-flops may be used depending upon the application. (As with FIG. 1, described above, flip-flops 120 and flip-flops 121 are all substantially identical.) Each of flip-flops 120 / 121 is part of the normal logic of circuitry 110 which is to be tested, generally along with other normal logic (not shown) which generates the data signals 16 - 1 through 16 -n normally applied to the data input terminals of flip-flops 120 / 121 , and/or which uses the registered output signals 30 - 1 through 30 -n of those flip-flops as in FIG. 1, described above.
Each flip-flop contains a master stage 122 / 123 , followed by a slave stage 124 . Input pass gate 126 is provided at the input to each master stage 122 / 123 from data signals 16 -n. Interstage pass gate 128 is provided at the input to each slave stage 124 from the output of each master stage 122 / 123 . Feedback pass gate 127 is provided on signal path 129 which extends from the output of slave stage 124 to the input of master stage 122 / 123 . In the preferred embodiment, pass gates 126 and 128 respond to a high signal to become enabled, and a low signal to become disabled. In contrast, pass gate 127 responds to a low signal to become enabled, and a high signal to become disabled. As illustrated in FIG. 3, signal 218 controls pass gates 126 , and signal 214 governs pass gates 127 . Signal 212 controls pass gates 128 and functions as a clock signal substantially as described for GCLK 12 - 1 with respect to FIGS. 1-2, above, with the differences noted below.
During normal operation, pass gates 126 and 128 govern the signal flow through flip-flops 120 / 121 . Pass gate 126 is enabled during a low clock phase for signal 212 while pass gate 128 is disabled. At that point, the signal on line 16 -n is passed to the input of master stage 122 / 123 . In the subsequent high clock phase, pass gate 126 is disabled while pass gate 128 is enabled. This enables the slave stage 124 to be overwritten with the contents of the master stage 122 / 123 .
The logic for generating signals 212 , 214 , and 218 is illustrated in FIG. 4 . (It is understood that the logic of FIG. 4 is exemplary, and that the signals for controlling the pass gates may be generated by other methods, such as additional logic or programming.) As described above, signal 212 controls the disabling and enabling of pass gate 128 . Multiplexer 180 , which receives SYSCLK 112 - 2 and its inverse, is controlled by signal CLK_RPI 112 - 1 . When CLK_RPI is high, signal SYSCLK 112 - 2 is passed uninverted as signal 210 . However, when CLK_RPI is low, signal 210 is the inverse of SYSCLK 112 - 2 . The ability to generate a clock signal and its inverse enables the circuitry to be used with flip-flops that are responsive to either a rising edge or a falling edge of the SYSCLK 112 - 2 signal.
Signal CLOSE_SLAVE 112 - 3 and signal 210 (the output of multiplexer 180 ) serve as inputs to NOR gate 130 , and signal 212 is the output thereof. During normal operation, CLOSE_SLAVE 112 - 3 is low, and thus NOR gate 130 functions effectively as an inverter to signal 210 . If CLK-RPI is low, the inverted SYSCLK signal will pass multiplexer 180 , and be inverted again as a result of passing through NOR gate 130 . When CLK_RPI is high, the uninverted SYSCLK signal is passed by the multiplexer, and inverted once at NOR gate 130 . During normal operation, when CLK_RPI is low, signal 212 is identical to SYSCLK, and when CLK_RPI is high, signal 212 is the inverse of SYSCLK.
Signal 218 is fed to pass gate 126 (FIG. 3) and controls the disabling and enabling thereof. Signal 218 is the output of NOR gate 132 , for which signal 212 , described above, serves a one of three inputs. The other two inputs are CLOSE_MASTER 112 - 4 and signal 216 , which is in turn the output of NOR gate 134 operating on inverted CLK_RPI and inverted CLOSE_SLAVE signals. During normal operation, CLOSE_MASTER and CLOSE_SLAVE are low, so that NOR gate 132 acts as an inverter on signal 212 . Consequently, the SYSCLK-related signals to pass gates 126 and 128 are of different polarity during normal operation, i.e. pass gates 126 and 128 are alternately enabled. If pass gate 126 is enabled by signal 218 , then pass gate 128 is disabled by the signal 212 . Conversely, when pass gate 126 is disabled by the signal 218 , pass gate 128 is enabled by signal 212 . This makes possible the initial reception of input 16 by each master stage 122 / 123 , and the subsequent transfer of the state of master stage 122 / 123 to the associated slave stage 124 after SYSCLK is toggled.
Signal 214 , which is the output of NAND gate 140 , controls the disabling and enabling of pass gate 127 . The three inputs to NAND gate 140 are CLOSE_SLAVE 112 - 3 , CLK_RPI 112 - 1 , and the inverse of CLOSE_MASTER 112 - 4 . During normal operation, i.e., when both CLOSE_SLAVE and CLOSE_MASTER are low, signal 214 is high, thus maintaining pass gate 127 in a disabled condition.
To initiate the scanout mode and suspend normal operation of circuit 110 , SYSCLK 112 - 2 is toggled and held to the low condition. CLOSE_MASTER 112 - 4 is then asserted to change signal 218 to the low condition, and pass gate 126 to master stage 122 / 123 is disabled. CLOSE_SLAVE 112 - 3 is subsequently asserted, SO that resulting signal 212 is low and signal 218 is low. Pass gates 126 and 128 are disabled in response to those respective signals. Thus the outputs from any elements on 16 - 1 through 16 -n are not passed on to flip-flops 120 / 121 .
As described above with respect to the embodiment of FIG. 1, additional structure is provided to facilitate the non-destructive scanout process. An inter-register pass gate 134 / 136 is provided between master stages of adjacent registers 120 / 121 . More particularly, a scan chain is formed as a series of master stages 122 / 123 having pass gates 134 alternating with pass gates 136 between adjacent master stages. Pass gates 136 are activated by clocking signal SCANCLKA 112 - 6 , while pass gates 134 are activated by clocking signal SCANCLKB 112 - 8 . This permits master stages 122 / 123 to be coupled in pairs. The coupling process is achieved by alternately enabling and disabling pass gates 134 and 136 in response to SCANCLKA and SCANCLKB.
The process of restoring the state of the flip-flops 120 / 121 may depend upon the phase of the clock. Restoring the state of the flip-flop is done by deasserting CLOSE_MASTER. This, in turn, determines whether the slave stage 124 has been overwritten with the contents of the master stage 122 / 123 at the time normal operation is suspended and scanout begins. The original state of each of the flip-flops 120 / 121 may be restored either from the device input 16 -n by enabling pass gate 126 , or alternatively, from the slave stage 124 along signal path 129 by enabling pass gate 127 . Depending upon whether signal 212 is high or low when scanout begins, pass gate 127 may be either enabled or disabled at that time.
If the phase of clock signal 212 is low when normal operation is suspended and scanout begins, then the slave stage 124 is not yet overwritten with the contents of the master stage 122 / 123 . The slave stage 124 continues to maintain the state from the previous clock iteration, and likewise, output 30 -n is unchanged. Pass gate 126 is enabled, so that the master stage 122 / 123 receives data based on device inputs at 16 -n and outputs from the flip-flops 30 -n. After scanout (in which both pass gates 126 and 128 are disabled), the master stage 122 / 123 is restored by re-enabling pass gate 126 . Each input 16 -n remains constant throughout the scan process and available to restore the master stage of the associated flip-flop 120 / 121 to its pre-scan state when pass gates 126 are re-enabled.
In contrast, if the phase of clock signal 212 is high when normal operation is suspended and scanout begins, the slave stage 124 has already received data from the master stage 122 / 123 and has been overwritten. (This occurs, e.g., when SYSCLK is low, signal 212 is high and CLK_RPI is high.) When the slave stage 124 is overwritten, the outputs 30 -n are updated as well. As a result, when the scanout process is complete, it may not be possible to restore the master stage 122 / 123 by enabling pass gate 126 . Instead, master stage is restored from the associated slave stage 124 on feedback path 129 by enabling pass gate 127 . The restoration process will be described in greater detail below.
After the first restoration, CLOSE_MASTER and CLOSE_SLAVE are returned to high and adjacent flip-flops are re-coupled such that each flip-flop 121 is now the first of each pair, and the contents of the master stages 123 of flip-flops 121 are scanned out, as will be described in greater detail below.
Lastly, the original state of each of the flip-flops 120 / 121 can be restored again by toggling CLOSE_MASTER and CLOSE_SLAVE to the low condition, thereby enabling the pass gate 126 associated with each master stage 122 / 123 . Normal operation of the circuit can then be resumed.
Operation of the Second Embodiment
The non-destructive scan procedure will now be described in greater detail with respect to an illustrative sequence of timing signals illustrated in FIGS. 5 a - 5 i and 6 a - 6 i , in conjunction with FIGS. 3 and 4. FIGS. 5 a - 5 i and 6 a - 6 i are exemplary, and it is contemplated that other timing sequences may be performed to conduct the scan procedure. FIGS. 5 a - 5 i and 6 a - 6 i are aligned such that signals represented in the FIGS. in the same horizontal position occur simultaneously. FIGS. 5 a - 5 i are illustrative of the scanout procedure when clock signal 212 is low when scanout begins. According to the embodiment of FIGS. 3-4, signal 212 is low when both CLK_RPI is low and SYSCLK is low (FIGS. 5 a - 5 i ). Alternatively, signal 212 is low when both CLK_RPI is high and SYSCLK is high (not shown in the FIGS.). FIGS. 6 a - 6 i illustrate scanout when clock signal 212 is high. In the exemplary embodiment, signal 212 is high when CLK_RPI is high and SYSCLK is low (FIGS. 5 a - 5 i ). Alternatively, signal 212 is high when CLK_RPI is low and SYSCLK is high (not shown in the FIGS.).
With reference to FIGS. 5 a - 5 i , normal operation is indicated in stage I. The global clock function is supplied by SYSCLK 12 - 1 , and flip-flops 120 / 121 operate with the adjoining circuit elements as normal. CLOSE_MASTER (FIG. 5 d ) and CLOSE_SLAVE (FIG. 5 e ) are both low. Clock signal 212 , which controls pass gate 128 is identical to SYSCLK (FIG. 5 c ). NOR gate 132 operates as an inverter on the signal 212 to produce signal 218 , which controls pass gate 126 (FIG. 5 g ). Signals 212 and 218 are therefore of opposite polarity during normal operation.
NAND gate 140 produces signal 214 , which is high during normal operation, such that pass gate 127 is disabled. The SCANCLKBEN (FIG. 5 i ) and SCANCLKA (FIG. 5 h ) signals are low. Consequently, the inter-register pass gates 134 / 136 between adjacent master stages are disabled.
The suspension of normal operation and the initiation of scan testing is represented at stage II of FIGS. 5 a - 5 i . In the example, SYSCLK is deasserted and remains low, and CLK_RPI is low. Thus, clock signal 212 is low at the time scanout begins. (A similar situation results if SYCLK and CLK_RPI are both high.) CLOSE_MASTER is toggled to the high condition at time t 1 (FIG. 5 d ). Consequently, signal 218 (FIG. 5 g ) is toggled to the low condition, and pass gate 126 is disabled for all flip-flops. Subsequently, CLOSE_SLAVE is toggled to the high condition at time t 2 (FIG. 5 e ). Signal 212 is low and remains low, and therefore pass gate 126 remains disabled. As long as all the master and slave latches are disabled, the outputs 30 of all registers 120 / 121 remain static, and as a result the inputs 16 to all registers will remain static (again assuming that all inputs to circuit 10 (other than scan control inputs) are held constant).
Subsequently, the scanout procedure for flip-flops 120 - 1 through 120 -n is commenced as indicated in stage III of FIGS. 5 a - 5 i . As with the embodiment described in FIG. 1, two adjacent flop-flips 120 / 121 form a pair in order to scan data from the first flip-flop 120 of each pair down to the bottom of the chain. As shown in FIGS. 5 a - 5 i , this process is initiated by toggling SCANCLKA high, starting at time t 3 (FIG. 5 h ) before SCANCLKBEN is toggled to the high condition. SCANCLKBEN is toggled shortly thereafter at t 4 (FIG. 5 i ).
During this scanout process, the contents of master stage 122 of the first flip-flop 120 of each S pair is passed to the master stage 123 of the second flip-flop 121 of the pair. In effect, master stage 123 of flip-flop 121 temporarily acts as a slave stage to master stage 122 of flip-flop 120 . SCANCLKA is toggled while SCANCLKBEN remains high. As SCANCLKA is toggled, data from flip-flops 120 is passed vertically downward and scanned out (via element 40 ) at the bottom of the chain (see FIG. 3 ).
The next step in the non-destructive scanout procedure is the recovery of the initial state as illustrated in stage IV in FIGS. 5 a - 5 i . SYSCLK remains low during this stage (FIG. 5 b ). Since no data is being scanned out, SCANCLKA and SCANCLKBEN are both low. CLOSE_MASTER is toggled from high to low at time t 5 (FIG. 5 d ), but CLOSE_SLAVE remains high (FIG. 5 e ). All pass gates 126 are re-enabled, while pass gates 128 and 127 remain disabled. Consequently, the initial state of all master stages 122 / 123 is recovered from the input at 16 -n.
The scanout procedure for flip-flops 121 - 1 through 121 -n is now initiated as indicated in stage V of FIGS. 5 a - 5 i . During this stage, flip-flops 120 / 121 are again paired. However, in this case, master stage 122 of each flip-flop 120 temporarily acts as a slave stage to master stage 123 of each flip-flop 121 to permit scanning of data from the master stages 123 of flip-flops 121 . CLOSE_MASTER is toggled back from low to high to disable pass gates 126 at time t 6 (FIGS. 5 d - 5 g ).
To begin scanout at stage VI, SCANCLKBEN is asserted at time t 7 before SCANCLKA (FIG. 2 d ), in contrast with scanout at stage III, described above. (SCANCLKA is toggled shortly thereafter at time t 8 .) As a result, data in the master stage 123 of each first flip-flop 121 in the pair of flip-flops 120 / 121 is passed to the master stage 122 of the second flip-flop 120 of the pair. Thus, the contents of the master stage 122 of flip-flop 120 are overwritten by the master stage 123 of flip-flop 121 . As in stage III, described above, SCANCLKA is toggled while SCANCLKBEN remains high. As SCANCLKA is toggled, data from flip-flops 21 is passed vertically downward. This data may be scanned out at the bottom of the chain.
The recovery stage, again referred to as stage IV in FIGS. 5 a - 5 i , recovers the initial state of the machine during normal operation in stage I prior to commencement of the scanout process. Once the data from flip-flops 121 have been scanned out, SCANCLKA and SCANCLKBEN remain in the low condition. The initial state is recovered by toggling CLOSE_MASTER from the high to the low condition at time t 9 (FIG. 5 d ). Consequently, pass gates 126 are re-enabled. CLOSE_SLAVE is toggled to the low condition at time t 10 (FIG. 5 e ). Once the initial state is recovered, normal operation may continue, as indicated by the resumption of SYSCLK at time t 10 (FIG. 5 b ).
Operation of circuit 110 will now be described for situations when clock signal 212 is high when scanout begins. Comparison of FIGS. 5 a - 5 i with FIGS. 6 a - 6 i will readily illustrate that inputs SYSCLK, CLOSE_MASTER, CLOSE_SLAVE, SCANCLKA, and SCANCLKBEN are identical regardless of whether CLK_RPI is high or low. However, toggling CLK_RPI from low to high will affect signals 212 , 214 , and 218 and therefore which pass gates 126 , 127 are enabled to restore flip-flops 120 / 121 . Normal operation is shown in stage I of FIGS. 6 a - 6 i . Signal 212 , which controls pass gate 128 is the inverse of SYSCLK (FIG. 6 c ). This permits falling-edge triggered flip-flops to be incorporated into the circuit 110 . Signals 212 and 218 are of opposite polarity during normal operation. NAND gate 140 produces signal 214 , which is high during normal operation, such that pass gate 127 is disabled. Pass gates 134 and 136 between adjacent master stages are disabled during normal operation because SCANCLKBEN (FIG. 6 i ) and SCANCLKA (FIG. 6 h ) signals are low.
The initiation of scan testing is represented at stage II of FIGS. 6 a - 6 i . SYSCLK is deasserted and remains low, signal 212 is high, and signal 218 is low. Pass gate 128 is thus enabled, such that the slave stage 124 is overwritten with the state of the master stage 122 / 123 , and outputs 30 -n are updated. CLOSE MASTER is toggled to the high condition at time t 1 (FIG. 6 d ), such that signal 218 remains in the low condition (FIG. 6 g ), and pass gate 126 is disabled. CLOSE_SLAVE is then toggled to the high condition at time t 2 (FIG. 6 e ), which changes signal 212 to the low condition, and therefore disables pass gate 128 .
The scanout procedure for flip-flops 120 - 1 through 120 -n is commenced as indicated in stage III of FIGS. 6 a - 6 i . This process, as described above, is initiated by toggling SCANCLKA high, starting at time t 3 (FIG. 6 h ) before SCANCLKBEN is toggled to the high condition at time t 4 (FIG. 6 i ). As SCANCLKA is toggled, data from flip-flops 120 is passed vertically downward and scanned out (via element 40 ) at the bottom of the chain (see FIG. 3 ).
The recovery of the initial state is illustrated in stage IV in FIGS. 6 a - 6 i . SYSCLK remains low during this stage (FIG. 6 b ); SCANCLKA (FIG. 6 h ) and SCANCLKBEN (FIG. 6 i ) are also low. CLOSE_MASTER is toggled from high to low at time t 5 (FIG. 6 d ), but CLOSE_SLAVE remains high (FIG. 6 e ). The logic, described with respect to FIG. 3, produces a low signal 214 for low CLOSE_MASTER. Therefore, pass gates 127 are re-enabled, while pass gates 126 and 128 remain disabled. Consequently, the initial state of all master stages 122 / 123 is recovered from slave stage 124 via line 129 .
The scanout procedure for flip-flops 121 - 1 through 121 -n is now initiated as indicated in stage V of FIGS. 6 a - 6 i . CLOSE_MASTER is toggled back from low to high to disable pass gates 127 at time t 6 (FIGS. 6 d - 6 g ). During this stage, flip-flops 120 / 121 are again paired. However, in this case, master stage 122 of each flip-flop 120 temporarily acts as a slave stage to master stage 123 of each flip-flop 121 to permit scanning of data from the master stages 123 of flip-flops 121 .
To begin scanout at stage VI, SCANCLKBEN is asserted at time t 7 (FIG. 6 j ) before SCANCLKA at time t 8 (FIG. 2 d ). As a result, data in the master stage 123 of each first flip-flop 121 in the pair of flip-flops 120 / 121 is passed to the master stage 122 of the second flip-flop 120 of the pair. Thus, the contents of the master stage 122 of flip-flop 120 are overwritten by the master stage 123 of flip-flop 121 . As in stage III, described above, SCANCLKA is toggled while SCANCLKBEN remains high. As SCANCLKA is toggled, data from flip-flops 121 is passed vertically downward. This data may be scanned out at the bottom of the chain.
The recovery stage, again referred to as stage IV in FIGS. 6 a - 6 i , restores the initial state of the machine during normal operation in stage I prior to commencement of the scanout process. Once the data from flip-flops 121 have been scanned out, SCANCLKA and SCANCLKBEN remain in the low condition. The initial state is recovered by toggling CLOSE_MASTER from the high to the low condition at time t 9 (FIG. 6 d ). Consequently, signal 214 is low, and pass gates 127 are re-enabled. Once the initial state is restored, CLOSE_SLAVE is toggled to the low condition at time t 10 (FIG. 6 e ), thereby changing signal 212 to the high condition, disabling pass gate 127 . Normal operation may continue, as indicated by the resumption of SYSCLK at time t 11 (FIG. 6 b ).
FIG. 7 illustrates a circuit 10 / 110 of this invention in a data processing system 302 . Data processing system 302 may include one or more of the following components: a processor 304 ; memory 306 ; I/O circuitry 308 ; and peripheral devices 310 . These components are coupled together by a system bus 320 and are populated on a circuit board 330 which is contained in an end-user system 340 .
System 302 can be used in a wide variety of applications, such as computer networking, data networking, instrumentation, video processing, digital signal processing, or any other application where the advantage of using programmable or reprogrammable logic is desirable. Circuit 10 / 110 (which can, for example, be a programmable logic device) can be used to perform a variety of different functions. For example, circuit 10 / 110 can be a processor or controller that works in cooperation with processor 304 . Circuit 10 / 110 may also be used as an arbiter for arbitrating access to a shared resource in system 302 . In yet another example, circuit 10 / 110 can be configured as an interface between processor 304 and one of the other components in system 302 . It should be noted that system 302 is only exemplary, and that the true scope and spirit of the invention should be indicated by the following claims.
It will be understood that the foregoing is only illustrative of the principles of this invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example the scanout of master stages 23 / 123 in stage VI above may be conducted prior to the scanout of master stages 22 / 122 in stage III. | Scan testing of logic circuitry is facilitated by providing register circuits, each having an input gate configured to selectively pass a data s signal applied to that register, a master stage configured to store a data signal passed by the input gate of that register, an interstage gate configured to selectively pass a data signal stored by the master stage of that register, and a slave stage configured to store a data signal passed by the interstage gate of that register. Inter-register gates are operatively arranged to selectively pass a data signal stored by the master stage of an associated respective first one of the registers to the master stage of an associated respective second one of the registers for storage by the master stage of that second one of the registers. During normal operation, circuitry is configured to alternately enable the input gates and the interstage gates, and to disable the inter-register gates. During a scan mode, circuitry is configured to disable the input gates and the interstage gates, and to alternately enable alternate ones of the inter-register gates. | 6 |
FIELD AND BACKGROUND OF INVENTION
This invention relates to an exapandable beam structure formed of a plurality of sides of scissor link members which may be readily extended to erect a beam from a collapsed position for usage.
In the past, there have been many applications of scissor link type structures applied to booms, towers, and supports of varying types. A continuous need for structures of this type, which can be retracted to a very compact configuration for transport and storage and expanded for use, has existed for a long time. Numerous examples of prior patented structures of this general type exist in the prior art. Some typical prior structures, for example, are shown in the following U.S. Pat. Nos. 156,842, 217,439; 1,511,679; 1,947,647; and 3,435,570. All of these prior structures have a point in common in that they have relatively low strength in the extended direction. As such they are not capable of withstanding high load conditions. Further, some of these structures have been made expandable through the use of very complicated extension means, such as centrally located telescopic booms or screw or guide structures to expand the same. The interconnection between the links in such prior structures provide the capability of the extension but fail to provide a structure with any tensile or compressive strength or any means for increasing the strength of the same.
SUMMARY OF PRESENT INVENTION
The present invention is directed to an improved beam structure which collapses to a very small compact unit to require a minimum of storage space. The compact size permits ease in handling and transportation of the same. The unit extends to a significant length so that it may be used as a tower or horizontally as a beam for a support. The application of such a structure is readily found in the need for towers in remote locations where it is not possible to transport even sections of a tower for final assembly because of difficulties in traversing rough terrain. Further, the structure has application as a beam in that it may be elongated and positioned horizontally or cantilever style to provide a frame support for temporary bridge structures or the like. The improved beam structure is a plural-sided structure having a plurality of main sides and a plurality of interconnecting sides, each of the sides being formed of a pair of scissor links connected end-to-end to provide the extent of the same. Block members interconnect the links of the main and intermediate sides, and in the extended position, the connecting side links move to an over center position such that they are substantially aligned to provide corners of the polygonal beam structure which is basically formed of the main sides. The intermediate links are of short length than the links of the main sections and the pivot means connecting the links at the corners are the block members which nest together in the expanded position. The block members include means for securing the block members together to maintain the beam in the extended position. In addition, the blocks have apertures therein which are aligned so that in the extended position, a tensioning rod or cable may be extended through the beam and secured to the ends of the same to apply tension to the beam to increase the strength of the same. The link sections pivot to expand and contract as a unit and the beam structure may be erected from a collapsed to an extended position either in a horizontal or a vertical position through an external pulling force means. When the beam structure is extended, it is locked in position and the tension means may be applied thereto to increase the strength of the same. It provides an extremely long or high beam which may be used as a tower or as a bridge support or equivalent structure and yet, in a collapsed position, may be readily transported to a place of usage.
IN THE DRAWINGS
FIG. 1 is a perspective view of the expandable beam structure in collapsed position;
FIG. 2 is a perspective view of the expandable beam structure in an extended position with parts broken away;
FIG. 3 is a sectional view of a portion of the beam structure taken along the lines 3--3 in FIG. 2; and,
FIG. 4 is a fragmentary perspective view of the portion of the beam structure showing the aperture for the tensioning means.
DESCRIPTION OF PREFERRED EMBODIMENT
My improved beam structure is shown in perspective in a collapsed and extended position in FIGS. 1 and 2, generally at 10. In the erected position, the beam structure is a generally three-sided figure and in the collapsed position, the main three sides indicated at 11, 12, and 13 have positioned therebetween intermediate sides numbered 14, 15 and 16. In the collapsed position on the beam structure when the individual links (to be later identified) are in a generally horizontal position, the general width of the sides 11, 12, and 13 correspond with the length of the main links. Similarly, the width of the intermediate sides 14, 15 and 16 correspond to the length of the links forming the intermediate sides. In the extended position, the links forming the intermediate sides of the beam structure pivot to a position in which they are substantially vertical and the width of the sides are substantially reduced to give a generally three-sided configuration to the beam. As will be seen in FIGS. 1 and 2, the main sides of the beams are formed by scissor links 20 which are pivotally connected to a midpoint and connected end-to-end to similar pairs of links extending throughout the sides of the beam. These links are flat metal plates of a given dimension and the pivots such as are indicated at 21 and 22 at the center and ends respectively of the link are formed by suitable nuts and bolts or rivets to allow the links to pivot. The links on the intermediate sides are identified at 30 and have a length dimension which is slightly greater than half the links 20 forming the main sides or generally at the ratio of 1:2. They are similarly pivoted through pivot means 31 at the midpoints and pivots 32 at the extremities to one another to allow the links to pivot in the conventional scissor link fashion. The intermediate sides 14, 15 and 16 are connected to the main sides 11, 12 and 13 by block members 40, 42 at the pivot points 22, 32.
As will be best seen in FIG. 3, the block members 40, 42 have flat and beveled sides such that the links 20 and 30 may pivot along the side and a suitable bolt means 45, 46 are fitted into tapped apertures in the block and provide pivot surfaces to define the pivots 32, 22 for the ends of the links and to interconnect the sides. The block 40 has a recess surface 47 therein and a complimentary recess surface 48 is provided in the block 42 such that the blocks may be brought together and overlap in the expanded position of the beam structure. A suitable aperture 50 is provided in the blocks 40, 42 in the recessed portion so that a threaded bolt 52 may be positioned therethrough and secure the blocks in abutting relationship and maintain the links in an expanded position.
As will be best seen in FIG. 3, for the expanded position of the beam structure, the blocks 40, 42 fit together and the surfaces of the intermediate sides formed of the links 30, which are pivoted to their substantially vertical position, provide a flat surface for the beam structure or an intermediate side surface which is determined by the width of the blocks. To secure the beam in an extended position, the bolt means 52 extends through each of the apertures 50 in the blocks 40, 42 to lock the blocks in an abutting position. In addition, a second aperture 60 is aligned through the blocks and this aperture, for each of the blocks forming a corner of the beam, will be aligned such that a suitable tensioning cable, such as is indicated at 70, may be placed therethrough. The cable may be anchored at one end and suitable tensioning means provided to tension the cable when the beam is in an expanded position to prestress the cable. This may provide a slight cantilever shape to the beam and will provide additional supporting force and tension at the particular corner in which the tensioning cable is positioned. The improved beam structure, for example, may be made of main links having a length of substantially 18 inches between pivot extremities with the intermediate links 30 having a length of approximately 101/2 inches between extremities. For such a beam the links may have a width of approximately 7/8 inch and a thickness of approximately 1/4 inch. A resultant beam structure in the extended position will provide a beam of approximately 14 inches to 15 inches on a side. The ratio of length between the collapsed and extended position for such a beam is in the ratio of 1:12 such that a 5 foot collapsed beam will produce an extended 60 foot beam. In a collapsed position, such a beam is readily transportable to a place of usage and may be extended to auxiliary means to elongate the same. After the blocks are secured, a tensioning cable may be connected to the beam to provide a generally superior and longer beam structure than is heretofore possible from a collapsed structure. When using the beam as a tower, one end of the beam would be securely anchored to an anchoring base and the beam structure elevated through suitable means, such as a lifting force of a helicopter, until the beam is completely extended. At that point, the corners may be locked and suitable guy wires attached to provide a supported tower having all the strength and load capacity of a conventional tower. The improved beam structure may be used not only as a temporary beam and tower but as a permanent building element where it is desired to have a structure readily transportable to a building site and yet extensible to a desired structure length with sufficient strength to support building structure.
While I have shown the preferred embodiment as a three-sided figure, it will be recognized that the beam or platform may be formed of a plural number of sides having the same number of main sides as intermediate sides with interconnections in the manner described above. Therefore, in considering this invention, it should be remembered that this disclosure is illustrative only and the scope of the invention should be determined by the appended claims. | The invention relates to an expandable beam structure comprising a plural-sided structure, each side formed of consecutive pairs of scissor links pivotally connected end-to-end to form a side. The plural-sided figure is connected by intermediate sides and the main sides are interconnected through pivot members which pivot the ends of the links and interconnect the sides. The pivot members combined to form a locking device to maintain the beam in an erected position and further support a tensioning means whenever it is desired to tension the beam. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from British Patent Application Number 1119037.8 filed 4 Nov. 2011, the entire contents of which are incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a network for distributing signals and power around a gas turbine engine using a flexible harness. In particular, this invention relates to clips for holding a flexible harness for a gas turbine engine.
2. Description of the Related Art
A typical gas turbine engine has a substantial number of electrical components which serve, for example, to sense operating parameters of the engine and/or to control actuators which operate devices in the engine. Such devices may, for example, control fuel flow, variable vanes and air bleed valves. The actuators may themselves be electrically powered, although some may be pneumatically or hydraulically powered, but controlled by electrical signals.
Electrical power, and signals to and from the individual electrical components, are commonly transmitted along conductors. Conventionally, such conductors may be in the form of wires and cables which are assembled together in a harness. In such a conventional harness, each wire may be surrounded by an insulating sleeve, which may be braided or have a braided cover. The connections between the individual components and the conventional harness are made, for example, by multi-pin plug and socket connectors. Similarly, communication between the harness and power, control and signalling circuitry is achieved through a multi-pin connector.
By way of example, FIG. 1 of the accompanying drawings shows a typical gas turbine engine including two conventional wiring harnesses 102 , 104 , each provided with a respective connector component 106 , 108 for connection to circuitry accommodated within the airframe of an aircraft in which the engine is installed. The harnesses 102 , 104 are assembled from individual wires and cables which are held together over at least part of their lengths by suitable sleeving and/or braiding. Individual wires and cables, for example those indicated at 110 , emerge from the sleeving or braiding to terminate at plug or socket connector components 112 for cooperation with complementary socket or plug connector components 114 on, or connected to, the respective electrical components.
Each conventional harness 102 , 104 therefore comprises a multitude of insulated wires and cables. This makes the conventional harness bulky, heavy and difficult to manipulate. It is desirable to reduce the size and weight of components on gas turbine engines, particularly, for example, gas turbine engines for use on vehicles, such as aircraft.
It is proposed to replace at least a portion of, for example all of, the conventional harness with a flexible printed circuit board harness (FPCB harness). An example of a portion of such a flexible printed circuit board harness 20 is shown in FIGS. 2 to 5 . FIG. 2 shows a perspective view of the FPCB harness portion, and FIGS. 3 , 4 , and 5 show side, top, and cross-sectional views respectively.
Such an FPCB harness 20 may comprise a flexible (for example elastically deformable) substrate 40 with conductive tracks 30 laid/formed therein. The FPCB harness 20 may thus be deformable. In the example shown in FIGS. 2 to 5 , the FPCB harness 20 extends along a length in the x-direction, a width in the y-direction, and a thickness (or depth or height) in the z-direction. The x direction may be defined as the axial direction of the FPCB harness. Thus, the x-direction (and thus the z-direction) may change along the length of the FPCB harness 20 as the FPCB harness is deformed. This is illustrated in FIG. 3 . The x-y surface(s) may be said to be the major surface(s) of the FPCB harness. In the example shown in FIGS. 2 to 5 , the FPCB harness is deformable in the z direction. i.e. in a direction perpendicular to the major surface. FPCB harnesses may be additionally of alternatively deformable about any other direction, and/or may be twisted about any one or more of the x, y, or z directions.
The flexible substrate 40 may be a dielectric. By way of example, the substrate material may be, by way of example only, polyamide. As will be readily apparent, other suitable substrate material could alternatively be used.
The conductive tracks 30 , which may be surrounded by the substrate, may be formed using any suitable conductive material, such as, by way of example only, copper, although other materials could alternatively be used. The conductive tracks 30 may be used to conduct/transfer electrical signals and/or electrical power, for example around a gas turbine engine and/or to/from components of a gas turbine engine and/or an airframe attached to a gas turbine engine. The size (for example the cross-sectional area) and/or the shape of the conductive tracks 30 may depend on the signal to be transmitted through the particular conductive track 30 . Thus, the shape and/or size of the individual conductive tracks 30 may or may not be uniform in a FPCB harness 20 .
The example shown in FIGS. 2 to 5 has 6 conductive tracks 30 running through the substrate 40 . However, the number of conductive tracks 30 running through a substrate 40 could be fewer than 6, or greater than 6. Indeed the number of conductive tracks 30 could be far greater than 6, for example tens or hundreds of tracks, as required. As such, many electrical signals and/or power transmission lines may be incorporated into a single FPCB harness.
A single FPCB harness 20 may comprise one layer of tracks, or more than one layer of tracks, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more than 10 layers of tracks. An FPCB harness may comprise significantly more than 10 layers of tracks, for example at least an order of magnitude more layers of tracks. In this regard, a layer of tracks may be defined as being a series of tracks that extend in the same x-y surface. Thus, the example shown in FIGS. 2 to 5 comprises 2 layers of tracks 30 , with each layer comprising 3 tracks.
Using an FPCB harness to transmit electrical signals and/or power is therefore advantageous over a conventional harness, for example because of its reduced size, weight and/or complexity.
In order to attach a harness to a component (for example to a gas turbine engine or related airframe), a clip is required. An example of a clip that may be used to attach a conventional harness to a gas turbine engine is shown in FIG. 7 . The clip 50 shown in FIG. 7 is configured to hold a cable, or a bundle of cables which form at least a part of a conventional wire cable harness. The clip 50 has a generally cylindrical outer casing 52 with a diameter 56 and a structural internal element 54 configured to provide strength to the clip 50 . The clip 50 shown in FIG. 7 also has teeth 56 configured to grasp the generally cylindrical conventional cable harness, although the teeth 56 may not be present in some conventional clips.
FIGS. 8 and 9 show an alternative clip 60 for holding a conventional cable harness. The clip 60 shown in FIGS. 8 and 9 comprises two arms 64 , 66 that define a space 62 therebetween for holding a conventional cable harness or bundle of cable harnesses. The space 62 defined between the two arms 64 , 66 may be generally cylindrical. The two arms 64 , 66 are sprung so as to be able to accommodate various diameters of conventional cable harnesses.
OBJECTS AND SUMMARY OF THE INVENTION
FPCB harnesses have properties that present difficulties when considering how to attach them to components, for example of a gas turbine engine. For example, the FPCB harnesses may have mechanical properties that mean that known clips, such as those described above, are not suitable for attaching them to components. Purely by way of example only, the flexible substrate material may be relatively easily damaged (for example punctured or sliced) by conventional clips.
As explained herein, FPCB harnesses offer considerable advantages over conventional harness in terms of, amongst other things, size and weight. It is desirable to maximize this size/weight benefit by providing an attachment device for allowing the FPCB harnesses to be connected to components in a compact, efficient manner. Conventional clips are therefore not desirable, or even suitable.
According to the an aspect of the invention, there is provided a gas turbine engine installation comprising at least two flexible printed circuit board harnesses arranged to transfer electrical signals around the engine installation, and at least one clip holding at least two flexible printed circuit board harnesses. Each clip comprises a first jaw and a second jaw that hold respective first and second flexible printed circuit board harnesses. The first and second jaws each comprise a set of directly opposing, non-overlapping, compliant teeth arranged to grip the respective harness.
The electrical signals can be of any type that may be transmitted along electrical conductors, for example electrical power transmission, and/or signals (for example control signals) to, from or between components (for example electrical components) of the gas turbine engine installation. The FPCB harnesses for transmitting the electrical signals may be as described herein, for example with reference to FIGS. 2 to 5 .
Because the sets of teeth in each jaw are directly opposing, their tips may not intermesh if the sets of teeth are pushed together. Instead, if the sets of teeth are pushed together (i.e. opposing teeth are moved towards each other), the tips of the opposing teeth may come into contact with each other, but cannot move past each other. As such, this arrangement of teeth means that the opposing teeth in a jaw cannot overlap (i.e. the tips of the upper set of teeth cannot move past than the tips of the lower set of teeth and vice versa), and thus cannot intermesh when pushed together.
An advantage of this arrangement of teeth in the jaws is that once the first flexible printed circuit board harness has been pushed into the first jaw and gripped by the respective teeth, the teeth of the second jaw do not (indeed cannot) intermesh. This means that the second flexible printed circuit board harness can be inserted into the second jaw even if the first flexible printed circuit board harness has already been inserted into the first jaw, because the teeth of the second jaw remain non intermeshed at all times. If the teeth of the second jaw were to intermesh, it would be extremely difficult, or even impossible, to insert the second flexible printed circuit board harness into the second jaw.
A further advantage of arranging the teeth to be directly opposing, non-overlapping and compliant is that it enables the respective FPCB harness to be appropriately gripped, whilst reducing (or substantially eliminating) the possibility of damage to the FPCB harness. For example, by avoiding the possibility of opposing teeth intermeshing, the FPCB harness can remain substantially flat within the jaw (for example without containing regions of high curvature), thereby reducing the possibility of damage, such a splitting or fretting, to the FPCB harness.
The invention provides a method of assembling a gas turbine engine installation. The method comprises providing at least two flexible printed circuit board harnesses arranged to transfer electrical signals (which, as explained above, may be of any type) around the engine installation. The method comprises attaching a first flexible printed circuit board harness to the rest of the gas turbine engine installation by inserting a portion thereof into a first jaw provided in a dip. The method comprises attaching a second flexible printed circuit board harness to the rest of the gas turbine engine installation, after attaching the first flexible printed circuit board harness, by inserting a portion thereof into a second jaw provided in the dip. Each jaw comprises a set of directly opposing, non-overlapping, compliant teeth, such that before and during the step of attaching the second flexible printed circuit board harness, the opposing teeth of the second jaw are not intermeshed.
This method provides various advantages, including those outlined above and elsewhere herein in relation to the gas turbine engine installation.
A gap may be provided between directly opposing teeth. Such a gap may be provided when the jaw is in an undeformed state, for example when no external forces are applied to it. The gap may be set to facilitate insertion of the FPCB into the jaw, whist providing sufficient grip to hold the FPCB in use. The gap may depend on the thickness of the FPCB harness intended to be inserted into the jaw. The gap may be set to allow FPCB harnesses with a range of thicknesses to be inserted.
The gap may be in the range of from 0.1 mm to 10 mm, for example 0.5 mm to 5 mm, for example 1 mm to 4 mm, for example 2 mm to 3 mm, for example on the order of 2.5 mm. In alternative arrangements, there may be no gap between opposing teeth in a jaw in the undeformed state. This may be particularly suitable for holding particularly thin FPCB harnesses.
The tips of (some or all of) the teeth may be blunt. This may mean that the tips of the teeth may not be sharp, or not pointed. It may mean that the tips of the teeth do not have an apex. Thus, the tips of the teeth may be squared off, i.e. the parts of opposing teeth that face each other may be flat surfaces, which may be parallel. The tips of the teeth may take other suitable shapes, such as a rounded shape.
Having blunt tips may help to reduce the pressure applied to the FPCB harness when it is gripped by the teeth. This may help to reduce, or substantially eliminate, the possibility of damage to the FPCB harness when it is gripped.
At least one of the first and second jaws may be formed using a material comprising one or more of ethylene-propylene rubber, a silicone based compound, and a nitrile material. These materials may provide good grip to a FPCB harness whilst being compliant so as to minimize the possibility of damage to the FPCB harness. The particular material may be chosen depending on the application, for example the environment (for example in terms of temperature variation) in which the clip is to be used and/or the type of FPCB harness it is to be used with.
At least one clip (for example all clips) may further comprise a support structure configured to resist changes in shape of the clip under operational loads. The support structure may be relatively more stiff than the jaws. As such, the support structure may help to reduce, or substantially prevent flexing of the clip, for example flexing of the external shape of the clip. This may help to ensure that the jaws retain the desired shape under load, for example it may help to ensure that the jaws don't flex apart more than a desired amount when a FPCB harness is inserted. This may help to ensure that the FPCB harnesses are clamped with the desired force.
The clip may comprise a main body that may incorporate the jaws. The main body may thus be integral with the jaws and, for example, manufactured from the same material and/or using the same process as the jaws. The support structure may extend around at least a part of the main body. This may be a convenient arrangement for providing structural support to the clip.
The support structure may be formed using a material comprising metal and/or a composite/fibre resin. The support structure may thus be constructed using a material that is more stiff than the main body and/or the jaws of the clip. This may allow the clip to be structurally stiff, whilst retaining compliant teeth for gripping the FPCB harness.
The support structure may further comprise an attachment portion used to attach the clip to the gas turbine engine, or a component thereof. Thus, the clip can be particularly compact, with a minimal number of parts required to attach it (and thus a FPCB harness) to a component. This may have further weight and/or size benefits.
Each flexible printed circuit board harness may be described as a thin, elongate member. Such a thin, elongate member may have a major surface defined by a length and a width, and a thickness normal to the major surface. The teeth of the clip may thus contact, and grip, the major surface (the elongate member may be said to have two parallel major surfaces offset by the thickness of the FPCB, with one set of teeth contacting and gripping one major surface and the other set of teeth contacting and gripping the other major surface).
The teeth of at least one clip may extend in a direction that corresponds to the length direction of the respective flexible printed circuit board harness when gripped. This may provide particularly strong resistance to the FPCB harness being pulled out of the jaw in the width direction.
The teeth of at least one clip may extend in a direction that corresponds to the width direction of the respective flexible printed circuit board harness when gripped. This arrangement may facilitate insertion of the FPCB harness into the clip, and/or may provide particularly strong resistance to the FPCB harness being pulled through the jaw in the length direction.
A lengthwise extending portion of the flexible printed circuit board harness may be held by two opposing clips, each opposing clip extending across no more than half of the width of the flexible printed circuit board harness. Such an arrangement may provide more secure retention of the FPCB harness. For example, such an arrangement may reduce (or substantially eliminate) the possibility of the FPCB harness being pulled out of a clip in a width direction.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with reference to the accompanying Figures, in which:
FIG. 1 shows a gas turbine engine with a conventional harness;
FIG. 2 shows perspective view of a portion of a flexible printed circuit board harness;
FIG. 3 shows a side view of the flexible printed circuit board harness of FIG. 2 ;
FIG. 4 shows a top view of the flexible printed circuit board harness of FIG. 2 ;
FIG. 5 shows a cross-sectional view of the flexible printed circuit board harness of FIG. 2 ;
FIG. 6 is a cross-section through a gas turbine engine;
FIG. 7 shows a side view of a clip for holding a conventional harness in place;
FIG. 8 shows a perspective view of an alternative clip for holding a conventional harness in place;
FIG. 9 shows a side view of the lip shown in FIG. 8 ;
FIG. 10 shows a perspective view of clip in accordance with the present invention;
FIG. 11 shows a side view of two clips according to FIG. 10 ;
FIG. 12 shows a front view of an alternative clip in accordance with the present invention; and
FIG. 13 shows a side view of two clips according to FIG. 12 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 6 , a ducted fan gas turbine engine generally indicated at 10 has a principal and rotational axis X-X. The engine 10 comprises, in axial flow series, an air intake 11 , a propulsive fan 12 , an intermediate pressure compressor 13 , a high-pressure compressor 14 , combustion equipment 15 , a high-pressure turbine 16 , and intermediate pressure turbine 17 , a low-pressure turbine 18 and a core engine exhaust nozzle 19 . The engine also has a bypass duct 22 and a bypass exhaust nozzle 23 .
The gas turbine engine 10 works in a conventional manner so that air entering the intake 11 is accelerated by the fan 12 to produce two air flows: a first air flow A into the intermediate pressure compressor 13 and a second air flow B which passes through the bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 13 compresses the air flow A directed into it before delivering that air to the high pressure compressor 14 where further compression takes place.
The compressed air exhausted from the high-pressure compressor 14 is directed into the combustion equipment 15 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 16 , 17 , 18 before being exhausted through the nozzle 19 to provide additional propulsive thrust. The high, intermediate and low-pressure turbines 16 , 17 , 18 respectively drive the high and intermediate pressure compressors 14 , 13 and the fan 12 by suitable interconnecting shafts.
The gas turbine engine 10 shown in FIG. 6 may be at least a part of a gas turbine engine installation according to the present invention. The gas turbine engine 10 may comprise FPCB harnesses (such as those described above in relation to FIGS. 2 to 5 ) for transmitting/transferring electrical signals around the engine and/or to/from the engine 10 from other components, such as components of an airframe. The function and/or construction of the FPCB harnesses may be as described above and elsewhere herein.
The FPCB harnesses may be attached to any part of the engine installation (of which the engine 10 may be a part) using a clip such as the clip 200 shown in FIGS. 10 and 11 . In each of FIGS. 10 and 11 , two clips 200 A, 200 B are shown. The two clips 200 A, 200 B may be used in conjunction with each other to hold opposing sides of a FPCB harness 20 . Alternatively, just one of the clips 200 may be used to hold a FPCB harness.
Each clip 200 has three jaws 202 , 204 , 206 extending from (or being a part of) a main body 201 . Each jaw 202 , 204 , 206 may be arranged to hold (or support) a respective FPCB harness 20 . In particular, each jaw 202 , 204 , 206 may be arranged to receive a portion of a respective FPCB harness 20 . The number of jaws corresponds to the number of FPCB harnesses that the clip 200 can hold. In the example shown in FIG. 11 , the clip 200 is capable of holding 3 FPCB harnesses, but is only shown holding 2 FPCB harnesses 20 . Other embodiments may thus comprise different numbers of jaws. For example, the clip 200 may have two jaws, or 4, 5, 6, 7, 8, 9, 10 or more than 10 jaws. It may also be possible to have clips with jaws of the type described and illustrated herein, but with only one jaw, although such clips with only one jaw would not have many of the advantages described herein in relation to the multi jawed clips.
Each jaw 202 , 204 , 206 has two sets of teeth, which may be referred to as an upper set of teeth 212 and a lower set of teeth 222 . The teeth in the upper set 212 directly oppose corresponding teeth in the lower set 222 . Thus, the tips of the teeth in both sets 212 , 222 are aligned. In the FIG. 11 example, the teeth in both sets 212 , 222 are aligned in the width direction of the FPCB harness that they are designed to hold, i.e. in the direction labelled ‘p’ in FIG. 11 . Note that the direction ‘p’ labelled in FIG. 11 corresponds to the width direction ‘y’ of the FPCB harness shown in FIGS. 2 to 5 when inserted.
A gap 232 is provided between opposing teeth, i.e. between the upper set of teeth 212 and the lower set of teeth 222 . This gap may be set according to the type of FPCB harness that the jaws 202 , 204 , 206 is designed to hold, for example the thickness of the FPCB harness. For example, the gap 232 may be set to be no greater than the thickness (the ‘z’ direction shown in FIGS. 2 to 5 ) of the FPCB harness being held. The gap 232 could be different for the jaws 202 , 204 , 206 of the same clip 200 , if, for example, the clip 200 is intended to carry/hold FPCB harnesses of different thicknesses. In the example shown in FIG. 11 , however, the gap 232 is the same for all jaws 202 , 204 , 206 .
Some embodiments may have no gap 232 between opposing teeth 212 , 222 . Such embodiments may be particularly suitable, for example, to holding especially thin FPCB harnesses. The opposing sets of teeth 212 , 222 do not, however, overlap in the direction labelled ‘q’ in FIG. 11 (which corresponds to the thickness direction of the FPCB harness shown in FIGS. 2 to 5 when installed). Thus the teeth 212 , 222 are not intermeshed. Indeed, because the upper and lower sets of teeth 212 , 222 are directly opposed to each other, they do not intermesh even if they are pushed together. Instead, the tips of two opposing teeth 211 , 213 may contact each other if pushed together in the ‘q’ direction, but may not pass each other.
Because the upper and lower sets of teeth directly oppose each other, and thus cannot overlap so as to become intermeshed, more than one FPCB harness can be inserted into the clip 200 (and subsequently gripped by the teeth 212 , 222 so as to be held) without undue difficulty. For example, even when one of the FPCB harnesses 20 has been inserted into one of the jaws (for example jaw 206 ), the opposing teeth of the other jaw(s) 202 , 204 are prevented from becoming intermeshed, and thus further FPCB harnesses can be inserted into those jaws 202 , 204 without undue hindrance.
In order to insert an FPCB harness 20 into a jaw 202 , 204 , 206 , any suitable technique could be used. For example, the FPCB harness 20 could be pushed into the respective jaw 202 , 204 , 206 in the width direction of the FPCB harness 20 , i.e. in the direction labelled ‘p’ in FIG. 11 , through the mouth 240 of the jaw 206 . Where only one clip 200 is used to hold a given FPCB harness 20 , no further steps may be required in order for it to be gripped by the sets of teeth 212 , 222 . Where two clips 200 A, 200 B are used to hold a FPCB harness 20 , the first clip 200 A may be secured to the desired component, the FPCB harness may be inserted into the first clip 200 A as described above, then the second clip 200 B may be slid over the other side (in a width sense) of the FPCB harness, then the second clip 200 B may be secured to the component. Of course, these are only examples of many possible ways in which an FPCB harness 20 could be attached to a component using one clip 200 or two clips 200 A, 200 B, and any suitable method may be used.
Once inserted, the FPCB harness is held by the clip 200 , for example through being gripped by the opposing teeth 212 , 222 , which may be compliant and/or flexible and/or elastically deformable. The teeth 211 , 213 of the FIGS. 10 and 11 embodiment have blunt tips 215 . The tips 215 are squared off, and thus do not terminate in a sharp point or line. The teeth 211 , 213 may thus be said to be truncated wedges. The teeth may be said to be elongate, with a longitudinal axis extending in the length direction of the FPCB harness that they are designed to receive.
FIGS. 12 and 13 show a further embodiment of clip 300 for use in the present invention. The clip 300 also has three jaws 302 , 304 , 306 . Each of the jaws 302 , 304 , 306 may receive a FPCB harness, although no such harnesses are shown in FIGS. 12 and 13 . The clip 300 of FIGS. 12 and 13 shares many aspects and/or features with the embodiment of FIGS. 10 and 11 . For example, each jaw 302 , 304 , 306 has opposing, non-overlapping sets of teeth 312 , 322 which share advantages with the sets of teeth 212 , 222 described above in relation to FIGS. 10 and 11 .
In the FIGS. 12 and 13 clip 300 , however, the teeth 311 , 313 are arranged at right angles to the direction of the teeth 211 , 213 in the FIGS. 10 and 11 embodiment. The teeth 311 , 313 in the FIGS. 12 and 13 embodiment are elongate teeth with a longitudinal axis running in the width direction ‘y’ of the FPCB harness 20 that they are designed to receive. Thus, in the FIGS. 12 and 13 clip 300 , the upper and lower sets of teeth 312 , 322 are aligned in the direction labelled ‘r’ in FIG. 12 , so as to be directly opposed.
The clips 200 , 300 shown in FIGS. 10 to 13 have a support structure 400 . The support structure provides support to the main body 201 , 301 of the clip so as to restrict or minimize flexing/bending of the clip 200 , 300 . The support structure 400 may thus be stiffer, for example constructed from a stiffer material, than the main body of the clip 201 , 301 . The support structure 400 shown in the Figures is attached (for example bonded) to external surfaces of the main body 201 , 301 . However, other arrangements of support structure 400 may be used. For example, the support structure may penetrate into the material of the main body 201 , 301 of the clips 200 , 300 , for example between the jaws. The support structure 400 shown in the Figures comprises two parts 410 , 420 , that may be attached together (for example by welding) to produce the final support structure 400 . Again, other constructions could be used in clips for alternative embodiments.
The support structure 400 shown in the figures has an attachment portion 430 which in the illustrated example comprises a hole for receiving a fixing element, such as a screw, bolt, or rivet) that is configured to allow the clip 200 , 300 to be attached to a component, for example of the gas turbine installation. As mentioned above, this may be a particularly convenient, lightweight and compact arrangement for connecting the clips 200 , 300 , and thus the FPCB harnesses 20 , to components. However, some clips for use in embodiments of the invention may not have a support structure 400 at all, or may have a support structure 400 without an attachment portion 430 .
Any suitable material may be used to manufacture the main body 201 , 301 of the clips 200 , 300 , which may be the same as the material used to manufacture the jaws 202 , 204 , 206 , 302 , 304 , 306 . For example, the material may comprise one or more of ethylene-propylene rubber, a silicone based compound, and a nitrile material. In clips which have a support structure 400 , the support structure 400 may be constructed from a stiffer material than the main body 201 , 301 , for example from a metal and/or a resin/fibre composite.
The clip 200 , 300 could be any suitable size required to hold a FPCB harness 20 . Purely by way of non-limitative example, and with reference to FIG. 10 , the width ‘w’ of the clip 200 , 300 may be in the range of from 5 mm to 200 mm, for example 10 mm to 150 mm, for example 25 mm to 100 mm, for example on the order of 50 mm. The length ‘l’ of the clip 200 , 300 may be in the range of from 5 mm to 500 mm, for example 10 mm to 200 mm, for example 25 mm to 100 mm, for example on the order of 50 mm. The height ‘h’ of the clip 200 , 300 may be in the range of from 0.5 mm to 50 mm for example 2 mm to 10 mm, for example 3 mm to 8 mm, for example on the order of 5 mm. In other embodiments, the dimensions ‘l’, ‘h’, and ‘w’ may be outside these ranges.
Where reference is made herein to a gas turbine engine installation, it will be appreciated that this term may include a gas turbine engine and/or any peripheral components to which the gas turbine engine may be connected to or interact with and/or any connections/interfaces with surrounding components, which may include, for example, an airframe and/or components thereof. Such connections with an airframe, which are encompassed by the term ‘gas turbine engine installation’ as used herein include, but are not limited to, pylons and mountings and their respective connections. The gas turbine engine itself may be any type of gas turbine engine, including, but not limited to, a turbofan (bypass) gas turbine engine, turbojet, turboprop, ramjet, scramjet or open rotor gas turbine engine, industrial
It will be appreciated that many alternative configurations and/or arrangements of the clips 200 , 300 other than those described herein may fall within the scope of the invention. For example, alternative arrangements of jaws 202 , teeth sets 212 , 222 , tooth geometry 211 (such as tip geometry 215 ), support structure 400 , and/or FPCB harness 20 may fall within the scope of the invention and may be readily apparent to the skilled person from the disclosure provided herein. Furthermore, any feature described and/or claimed herein may be combined with any other compatible feature described in relation to the same or another embodiment. | A gas turbine engine installation is provided that has a plurality of flexible printed circuit board (FPCB) harnesses to transfer electrical signals, including electrical power, around a gas turbine engine. The plurality of FPCB harnesses is held to the gas turbine engine installation using clips that have at least two jaws. Each jaw has two sets of opposing teeth that do not intermesh, and cannot intermesh when pushed together. This allows more than one FPCB harness to be held by one clip without the risk of damaging the FPCB harnesses. Preventing the teeth from intermeshing also allows subsequent FPCB harnesses to be inserted into the clip without undue difficulty even after a first FPCB harness has already been inserted. | 7 |
This invention deals with novel building blocks and their use to build inexpensive, decorative walls and buildings, and the like.
More specifically, this invention deals with certain specific building blocks that when used in combination are useful to build decorative, strong, durable, decorative buildings and walls.
The blocks are multi-faceted such that all of the outside faces of the blocks will match each of the other faces of the block and allow the construction of walls having unique decorative effects, while overcoming the problems associated with standard rectangular building blocks of the prior art.
FIELD OF THE INVENTION
There are many various building blocks in use today, are manufactured primarily from cementitious materials. Many of these blocks have been developed with configurations having essentially the same outside surface, that is a rectangular block. When the rectangular building blocks are used to fabricate walls, the aesthetics of the wall leave much to be desired, in that essentially only a straight linear wall, with a vertical surface is created. Generally, only 90° corners can be used if a turn in the wall is required. Further, walls constructed with such blocks do not have the appropriate configurations to enable one to conveniently use iron rod and the like to stabilize the walls, and usually, these walls have to be laid on a concrete foundation in order to stand straight over a long period of time.
None of the building blocks in use today can be used to fabricate a strong, durable, decorative wall in which various angles can be built into the linear design. Further, walls can be built in serpentine configurations and various angled corners, in addition to 90° corners can be had, and, the blocks can be manufactured by conventional rectangular block manufacturing processes.
THE PRIOR ART
In the opinion of the inventors herein, the following patents all show rectangular block configurations and do not anticipate nor make obvious the blocks of the instant invention.
U.S. Pat. Nos. 767,414, issued Aug. 1, 1904 to Kidder; 1,154,546, issued to Peters on Sep. 21, 1915; 1,700,542, issued on Jan. 29, 1929 to O'Donnell; 1,234,990, issued Jul. 31, 1917 to Wilson; 1,816,916, issued Aug. 4, 1931 to Sentrop; 2,040,627, issued May 12, 1936; 2,185,497, issued Jan. 2, 1940 to Cilento et al.; 2,263,914, issued Nov. 25, 1941 to Bohn; 2,655,032, issued Oct 13, 1953 to Zagray; 2,749,739, issued Jun. 12, 1956 to Zagray; 2,881,614, issued Apr. 14, 1959 to Preininger; 3,209,510, issued Oct. 5, 1965 to Nakanishi; 3,534,518, issued Oct. 20, 1970 to Zagray; 3,609,926, issued Oct. 5, 1971 to Muse; 4,075,808, issued Feb. 28, 1978 to Pearlman; 4,285,179, issued Aug. 25, 1981 to Goidinger; 4,295,313, issued Oct. 20, 1981, to Rassias; 4,335,549, issued Jun. 22, 1982 to Dean; 4,425,748, issued Jan. 17, 1984 to De Waele; 4,590,729, issued May 27, 1986 to Hegazi; 5,048,250, issued Sep. 17, 1991 to Elias, and 5,291,711, issued Mar. 8, 1994 to Kopaz.
Thus, none of the art known to the inventors is believed to anticipate or make obvious the building blocks of the instant invention or their use to build walls.
THE INVENTION
The invention described herein deals with novel multi-faceted interfacial building blocks that are useful for constructing walls and the like.
Specifically, the invention described herein deals with a novel building block wherein said block has a short vertical axis and a horizontal linear axis and a flat upper surface, a flat bottom surface, two identical flat end surfaces and at least two side surfaces.
The block has a small, vertical, centered first opening through it and has a cavity adjacent one side of the small, vertical, centered first opening.
The side surfaces and flat end surfaces have a vertical, essentially centered, channel therein and each flat end surface has a semi-cavity in it adjacent the vertical channel therein and the block has two, large, second openings near each flat end, wherein each of the large second openings is situated essentially equidistant from each flat end.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a full top view of a block which is one embodiment of this invention.
FIG. 2 is a full top view of a block which is another embodiment of this invention in which a long, linear, horizontal axis for the block is designated as A--A which is the longest axis of the block, and in which the short, vertical axis is designated by the point B. The vertical axis for purposes of discussion and clarification herein is shown at point B and should be considered to run perpendicular to the plane of the paper on which FIG. 2 is situated.
FIG. 3 is a full top view of a block which is yet another embodiment of this invention.
FIG. 4 is an full end view of the block of FIG. 3 showing the short, vertical axis B as being vertical on the surface of the paper on which the drawing is situated, while the long, linear, horizontal axis for the block is designated as point A, and only for purposes of discussion and clarification herein is shown to run perpendicular to the plane of the paper on which FIG. 4 is situated.
FIG. 5 is a partial, perspective view of the edge of the block of FIG. 1.
FIG. 6 is a top view of a portion of a wall fabricated from the block of FIG. 2 showing a portion of the various arrangements that can be had with the blocks of this invention.
DETAILED DESCRIPTION OF THE INVENTION
This invention deals with novel multi-faceted interfacial building blocks that will allow the construction of a wall which is strong, durable, decorative and easy to build.
As can be observed from FIGS. 2 and 4, the blocks have a long axis as denoted by the line A--A, and a short axis denoted by the line B--B. For purposes of the description of the blocks herein, reference will be made with regard to the long axis and the short axis, without there being any intent on the part of the inventors herein to require that the blocks have any particular orientation to be within the scope of the claims herein.
With reference to FIG. 1, there is shown a top view of a block 1 which is one embodiment of this invention, in which there is shown a top surface 2. The top surface 2 is intended to accommodate other blocks that are set thereon, and therefore, the surface has to be essentially smooth. Again, with reference to FIG. 1, there is shown a channel 3 in the end 4 of the block 1, and a semi-cavity 5. The channel 3 is intended to match with a similar channel 3 in the end 4 or 6 of another adjacent block to form a round hole capable of receiving steel rod. It should be noted that there is an identical channel 3 and semi-cavity 5 in the opposite end 6 of the block 1. It should be noted further that there is an identical channel 7 in each of the faceted side surfaces 8, shown in FIG. 1 as encompassed by the braces.
In addition, there is shown two, large vertical openings 9 (second openings) through the block 1, and it should be noted that these openings are situated such that they are essentially equidistant from the ends 4 and 6 of the block 1 in order that the blocks are uniform, and can be turned end to end and still match all of the channels and openings. The size of these second openings is such that they are able to cut down on the overall weight of the block 1, yet maintain enough concrete as a bridge between openings and channels, to maintain the required strength.
Finally, there is shown a small, vertical opening 10, centered in the middle of the block 1, which vertical opening is intended to receive steel rod. An adjacent cavity 11, which is not bored entirely through the block is also shown in FIG. 1. This cavity 11 is intended to receive pins (not shown), which lock the blocks together during and after construction.
FIG. 3 is yet another embodiment of this invention in which the side surfaces 8 are essentially flat and in which there are only two such surfaces 8 for each side of the block. This particular configuration is the only block that cannot be configured to fit interfacially with the other blocks, in that its interfacial sides are too large.
FIG. 4 is an end view of the block of FIG. 3, and shows the channel 3, the cavity 5. Also shown is the vertical axis in line B--B, and the long, horizontal, linear axis shown as point A.
FIG. 5 is a side view of the block of FIG. 1, in which there is shown the side surface 8, and the channels 7. It will be remembered that the configuration of the block of FIG. 1 is such that there is a cleft 12 in each corner of the block 1.
Throughout this disclosure, the side surfaces have been described as side surface 8, and this side surface in each of the blocks is what allows for the many unique configurations that the blocks of this invention can have and from which the term "multi-faceted, interfacial" is derived for purposes of this invention.
It should be obvious to those skilled in the art, upon a reading of this specification and drawings that the blocks of this invention are unique and because of their multi-faceted configurations, can be used to create wall structures having many optional configurations.
For example, using the block configuration of FIG. 2, there is shown in FIG. 6, a first angle at 45° and another at 90° in a portion of a wall when viewed from the top.
Some of the various block configurations can be interchanged to give yet more options with regard to the angles that can be built into the wall, and the decorative effect that can be built into the wall.
The blocks of this invention have essentially symmetrical halves. When two of the blocks are adjacent to each other, such that the two cavities 5 are aligned, a full cavity 10 is formed, which then can receive a steel pin.
The overall dimensions of the blocks of this invention are essentially the same as the standard, commercial rectangular blocks however, the blocks of this invention can be manufactured to any reasonable thickness, on the order of 1 inch to 12 inches in thickness.
It should also be understood by those skilled in the art that these blocks can be used to construct buildings as well as walls, wherein they are mortared together rather than just being stacked on each other and bound by steel rod surrounded by cement. | Novel building blocks are used to build inexpensive, decorative walls and building, and the like. The blocks are multi-faceted such that all of the outside faces of the blocks will match each of the faces of other blocks and allow the construction of walls having unique decorative effects, while overcoming the problems associated with standard rectangular building blocks. | 4 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a continuation application of U.S. patent application Ser. No. 12/490,067, filed Jun. 23, 2009, which claims priority to and benefit from U.S. Provisional Patent Application No. 61/075,726, filed Jun. 25, 2008, both of which are commonly assigned and incorporated herein in their entirety by reference for all purposes.
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
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REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK
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BACKGROUND OF THE INVENTION
The present invention relates generally to monolithic techniques for micromachined technologies and integrated circuits. More particularly, the present invention provides a method and resulting device including both MEMS and integrated circuits using standard foundry compatible processes. Merely by way of example, the invention can be applied to microphones, motion sensors, rf devices, bio-systems and sensors, energy devices, pressure sensors, motors, electric generators, combinations of these, and the like.
Micromachined inertial sensors have been widely used in automotive and industrial applications for the past decades. Micromachined sensors have many advantages over macro electromechanical sensors. Micromachined devices are fabricated in a similar way as IC chips and have significant reduction in form factor. In addition, micromachined sensors have superior performance, lower power, and lower cost comparing to macro electromechanical sensors.
The incumbent micromachined inertial technologies, however, are based on MEMS fabrication processes such as bulk and surface micromachining techniques, which limit the level of integration of MEMS and CMOS, and are difficult to scale and leverage IC foundries' capability and capacity.
Thus, it is desirable to have an architecture that enables monolithically integration of MEMS on CMOS using IC foundry-compatible processes, which yields the highest performance, smallest form factor, and lowest cost comparing to the incumbent MEMS inertial sensors.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to integrating an inertial mechanical device on top of a CMOS substrate monolithically using IC-foundry compatible processes. The CMOS substrate is completed first using standard IC processes. A thick silicon layer is added on top of the CMOS. A subsequent patterning step defines a mechanical structure for inertial sensing. Finally, the mechanical device is encapsulated by a thick insulating layer at the wafer level.
Comparing to the incumbent bulk or surface micromachined MEMS inertial sensors, the vertically monolithically integrated inertial sensors have smaller chip size, lower parasitics, higher sensitivity, lower power, and lower cost.
Using this architecture and fabrication flow, it is also feasible and cost-effective to make an array of inertial sensors for sensing multiple axes of accelerations on a single chip.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified cross section diagram of components of a starting CMOS substrate according to one embodiment of the present invention.
FIG. 2 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 3 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 4 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 5 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 6 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 7 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 8 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 9 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 10 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 11 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 12 is a simplified cross section diagram of a components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIGS. 13A and 13B are simplified cross section diagrams of an alternative method of controlling silicon layer thickness of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIGS. 14A and 14B are simplified cross section diagrams of an alternative method of controlling silicon layer thickness of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIGS. 15A and 15B are simplified cross section diagrams of a alternative method of controlling silicon layer thickness of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIGS. 16A , 16 B, and 16 C are simplified cross section diagrams of double mechanical layer architecture of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIGS. 17A , 17 B, and 17 C are simplified cross section diagrams of double mechanical layer architecture of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 18 is a simplified cross section diagram of process flow of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
FIG. 19 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a simplified cross section diagram of components of a starting CMOS substrate according to one embodiment of the present invention. As depicted, the starting substrate is a fully processed CMOS wafer. A dielectric layer such as oxide and nitride is deposited on top of a top metal layer of the CMOS wafer. The dielectric layer is then patterned to form a structure that provides anchor points for stationary members of the mechanical sensing device.
FIG. 2 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, a silicon wafer is bonded to the CMOS substrate. The bonding methods include but not limited to: covalent, Sprin-on-glass (SOG), Eutectic, and anodic. The bonding temperature is CMOS compatible and below 400 C.
FIG. 3 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the silicon substrate is thinned by techniques such as grinding, polishing, and etching. The final thickness of the remaining silicon atop of the CMOS is precisely measured by infrared interferometry method with nanometer accuracy. Infrared wavelength is used because silicon is transparent in this spectrum.
FIG. 4 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, a VIA hole is etched into the silicon and top dielectric layers and stop on the top metal layer. The size of the VIA ranges from 0.5 um to a few micro meters depending on the thickness of the silicon layer. The profile or sidewall of the VIA is tapered or slopped for better step coverage of subsequent metalization step.
FIG. 5 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, a metal layer is blanket deposited on the wafer covering the silicon surface as well as the VIA surface. CVD or PVD recipes are optimized to achieve good step coverage of the VIA as well as low stress of the metal film. In one embodiment, the metal layer is a CVD TiN material that has excellent step coverage of the VIA. The thickness of the metal ranges from a few hundreds of angstroms to a few micro meters depending the applications requirements. An optional electroplating step can be used to fill the entire VIA with metals such as Copper or Nickel.
FIG. 6 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the silicon layer is patterned typically by a DRIE step. For a capacitive inertial sensor, the mechanical structure includes a proof mass connected with springs, movable comb fingers and stationary comb fingers that anchored to the top oxide. The springs have desired stiffness/compliance that allows the proof mass to move at certain external acceleration. The comb fingers moving along with the proof mass couples to stationary comb fingers capacitively. The movement cause a change in capacitance between the movable comb fingers and stationary comb fingers. The capacitance change is detected by the integrated circuits a few micrometer below.
FIG. 7 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, an organic sacrificial material is deposited covering the mechanical structure. In one embodiment, the sacrificial material is a liquid photo resist that is spin coated on the wafer and fill all the VIA holes and trenches. In another embodiment, the sacrificial material is a dry film photoreisit that is deposited on the surface of the wafer and does not fill the holes and trenches.
FIG. 8 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the photo resist is patterned by an exposure and develop lithography process. The exposed area are non-trench features such as proof mass and anchors.
FIG. 9 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the 1 st layer of the encapsulation is deposited by a PVD process. The deposition recipe is optimized for non-conforming purpose, which has little step coverage of the sidewall of the exposed photoresist trenches.
FIG. 10 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the sacrificial organic material is then removed by a dry O2 plasma ashing step. The removal of the sacrificial material releases the sensor device and forms the 1 st shell of the encapsulation.
FIG. 11 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the 2 nd layer of the encapsulation is deposited onto the 1 st layer. The sealing methods include PVD, spin-on, or spray-on techniques. The sealing materials include metal such as Ti, TiN, amorphous silicon, spin-on-glass, spray-on-glass, or a combination of the above. The ambient during sealing is optimized and controlled to a desired spec that defines the sensor device ambient after sealing. A getter material such as Ti can be deposited as the 1 st layer of the encapsulation and activated later to achieve high vacuum and cleanness of the sensor ambient environment. After sealing the holes, an optional CVD dielectric material such as oxide or nitride can be added onto the encapsulation.
FIG. 12 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As shown, a bond pad structure is formed. The bond pad structure can be formed by pattern and etch techniques known in the art, but can also be others depending on the application.
FIGS. 13A and 13B are simplified cross section diagrams of an alternative method of controlling silicon layer thickness of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted in FIG. 13A , a VIA structure is formed in a desired depth in the silicon substrate prior to bonding. The VIA is filled with materials such as Copper or Tungsten. As illustrated in FIG. 13B , the VIA is exposed during the thinning step and provide an end-point signal that control the remaining silicon thickness.
FIGS. 14A and 14B are simplified cross section diagrams of an alternative method of controlling silicon layer thickness of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted in FIG. 14A , the blanket silicon wafer is a SOI wafer with a desired SOI thickness. As illustrated in FIG. 14B , the BOX of the SOI provides an etch stop during the thinning process steps. The BOX can be then used as a hard mask to define the sensor structure.
FIGS. 15A and 15B are simplified cross section diagrams of a alternative method of controlling silicon layer thickness of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted in FIG. 15A , the blanket silicon wafer has a layer of implanted H 2 , He, or Ar in a desired thickness in the silicon substrate. As illustrated in FIG. 15B , this thickness of silicon is separated from the bulk at the implant layer. Separation methods include thermal cleave and mechanical cleave. A subsequent polishing or etching step smoothens the cleaved surface of the remaining silicon layer.
FIGS. 16A , 16 B, and 16 C are simplified cross section diagrams of double mechanical layer architecture of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted in FIG. 16A , the blanket silicon substrate is a SOI wafer with desired SOI thickness. After the bonding, a thinning process is followed to defined a desired thickness of the remained silicon in the bulk portion of the SOI substrate as illustrated in FIG. 16B . The thickness control techniques include methods aforementioned, Infrared interferometery, VIA end-point, or double SOI substrate. As shown in FIG. 16C , the sensor structure is then defined by etching steps. With double layered mechanical structure, various configurations can be designed to achieve desired performance. In one embodiment, the SOI is a thin layer with submicron thickness that provides as torsional springs for out-of-plane movement of the proof mass. In another embodiment, the thin SOI layer defines a flat spring that is compliant in the vertical dimension for Z-axis linear acceleration sensing, for example. In short, dual-layer mechanical structure gives more design flexibility and freedom for inertial sensor design.
FIGS. 17A , 17 B, and 17 C are simplified cross section diagrams of double mechanical layer architecture of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted in FIG. 17A , piezoresistors are embedded in the SOI substrate prior to bonding. After the bonding, a thinning process is followed to defined a desired thickness of the remained silicon in the bulk portion of the SOI substrate as illustrated in FIG. 17B . The thickness control techniques include methods aforementioned, Infrared interferometery, VIA end-point, or double SOI substrate. As shown in FIG. 17C , the sensor structure is then defined by etching steps. The spring member is formed in the SOI layer with the piezoresistors located in the mostly sensitive region. As the proof mass moves responding to an external acceleration, the springs deforms accordingly. As a result, the strain generated in the springs change the resistance of the piezoresistors. The change in resistance is detected by the integrated circuits a few micron below.
FIG. 18 is a simplified cross section diagram of process flow of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, a mechanical layer is formed by the follows: 1) defining cavity in the CMOS substrate, 2) fill the cavity with sacrificial organic material, 3) deposit mechanical material such as metal, amorphous silicon ranging from few micron to 10s of microns, 4) define sensor structure and remove sacrificial material. Using this process flow, multiple mechanical structure layers can be defined. For example, a dielectric layer can be added between the 1 st the 2 nd mechanical layer deposition.
FIG. 19 is a simplified cross section diagram of components of a monolithically integrated inertial sensing device according to one embodiment of the present invention. As depicted, the MEMS and WLP layers are stacked on top of the CMOS layers vertically and have similar cost structure as the CMOS layers. Since MEMS and WLP typically require thick material, additional material layer costs are added to the mask layers. This architecture leverages IC foundries' infrastructure, capability, and process control to achieve high yield. It can also take advantage of IC foundry's ‘older’ technology nodes' low cost and enormous capacity to make MEMS devices in high volume and at low cost.
It is also understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. | The present invention relates to integrating an inertial mechanical device on top of a CMOS substrate monolithically using IC-foundry compatible processes. The CMOS substrate is completed first using standard IC processes. A thick silicon layer is added on top of the CMOS. A subsequent patterning step defines a mechanical structure for inertial sensing. Finally, the mechanical device is encapsulated by a thick insulating layer at the wafer level. Comparing to the incumbent bulk or surface micromachined MEMS inertial sensors, the vertically monolithically integrated inertial sensors have smaller chip size, lower parasitics, higher sensitivity, lower power, and lower cost. | 1 |
FIELD OF THE INVENTION
The present invention relates generally to a new metal/magnetic-ceramic laminate with through-holes and such magnetic-ceramic materials as low temperature sintered ferrites and process thereof. More particularly, the invention encompasses new sintering aids for low temperature sintering of ferrites and process for fabrication of a large area ceramic laminate. The present invention also relates to a magnetic matrix display (MMD) electron beam source, and methods of manufacture thereof.
BACKGROUND OF THE INVENTION
A magnetic matrix display is particularly, although not exclusively, useful in display applications, especially flat panel display applications. Such flat panel display applications include television receivers, visual display units for computers, especially, although not exclusively, portable and/or desktop computers, personal organizers, communications equipment, wall monitor, portable game unit, virtual reality visors and the like. Flat panel display devices based on a magnetic matrix electron beam source hereinafter may be referred to as Magnetic Matrix Displays (MMD).
Conventional flat panel displays, such as liquid crystal display panels, and field emission displays, provide one display technology. However, these conventional flat panel displays are complicated and costly to manufacture, because they involve a relatively high level of semiconductor fabrication, delicate materials, and high tolerance requirements.
U.S. Pat. No. 5,917,277, (Knox, et al.), issued on Jun. 29, 1999, entitled “ELECTRON SOURCE INCLUDING A PERFORATED PERMANENT MAGNET”, assigned to International Business Machines Corporation, Armonk, N.Y., USA, the assignee of the instant Patent Application and the disclosure of which is incorporated herein by reference, discloses a magnetic matrix electron source and methods of manufacture thereof. Also disclosed is the application of the magnetic matrix electron source in display applications, such as, for example, flat panel display, displays for television receivers, visual display units for computers, to name a few. Also disclosed is a magnetic matrix display having a cathode for emitting electrons, a permanent magnet with a two dimensional array of channels extending between opposite poles of the magnet, the direction of magnetization being from the surface facing the cathode to the opposing surface. The magnet generates, in each channel, a magnetic field for directing electrons from the cathode means into an electron beam. The display also has a screen for receiving the electron beam from each channel. The screen has a phosphor coating facing the side of the magnet remote from the cathode, the phosphor coating comprising a plurality of pixels each corresponding to a different channel. There are grid electrode means disposed between the cathode means and the magnet for controlling the flow of electrons from the cathode means into each channel. The two dimensional array of channels are regularly spaced on an X-Y grid. The magnet area is large compared with its thickness. The flat panel display devices based on a magnetic matrix electron source is referred to as MMD (Magnetic Matrix Display).
The permanent magnet is used to form substantially linear, high intensity fields in the channels or magnetic apertures for the purpose of collimating the electrons passing through the aperture. The permanent magnet is insulating, or at most, has a low conductivity, so as to allow a field gradient along the length of the aperture. The placement of the beam so formed, on the phosphor coating, is largely dependent on the physical location of the apertures in the permanent magnet.
In operation, these electron beams are directed at a phosphor screen and collision of the electron beam with the phosphor results in light output, the intensity being proportional to the incident beam current (for a fixed final anode voltage). For color displays, three different colored phosphors (such as red, green and blue) are used and color is obtained by selective mixing of these three primary colors.
For accurate color reproduction, the location of the electron beams on the appropriate colored phosphor is essential.
Some degree of error may be tolerated by using “black matrix” to separate the different phosphors. This material acts to delimit individual phosphor colors and also enhances the contrast ratio of the displayed image by making the display faceplate appear darker. However, if the electron beam is misplaced relative to the phosphor, initially the light output from the phosphor is reduced (due to loss of beam current to the black matrix) and this will be visible as a luminance non-uniformity. If the beam is subject to a more severe placement error, it may stray onto a different colored phosphor to that for which it was intended and start to produce visible quantities of light output. Thus the misplaced electron beam is actually producing the wrong light output color. This is called a purity error and is a most undesirable display artifact. For a 0.3 mm pixel, typical phosphor widths are 67 μm with 33 μm black matrix between them.
It will be apparent that a very precise alignment is required between the magnet used to form the electron beams and the glass plate used to carry the phosphors that receive the electron beams. Further, this precise alignment must be maintained over a range of different operating conditions (high and low brightness, variable ambient temperature etc).
A number of other magnet characteristics are also important when considering application for a display, such as, for example:
(a) It is generally accepted that the displayed image is formed by a regular array of pixels. These pixels are conventionally placed on a square or rectangular grid. In order to retain compatibility with graphics adaptors the magnet must thus present the electron beams on such an array.
(b) In operation, the spacing between the grids used for bias and modulation of the electron beam and the electron source determines the current carried in the electron beam. Variations of this spacing will lead to variations in beam current and so to changes in light output from the phosphor screen. Hence it is a requirement that the magnet, which is used as a carrier for these bias and modulation grids, maintain a known spacing to the electron source. To avoid constructional difficulties, the magnet should be flat.
(c) The display will be subject to mechanical forces, especially during shipment. The magnet therefore must retain structural integrity over the allowable range of stresses it may encounter. A commonly accepted level is an equivalent acceleration of about 30 G (294 ms −2 ).
(d) Since the magnet is to be used within the display, which is evacuated, it should not contain any organic components which may be released over the life of the display thereby degrading the quality of vacuum or poisoning the cathode.
(e) The magnet should be magnetized in the direction of the apertures, that is the poles correspond to the faces of the magnet.
The manufacture of such a magnet that satisfies the above conditions is not possible by the use of previously known manufacturing methods. Certainly a magnet (ferrite, for example) of the desired size without apertures is readily obtainable but the presence of the apertures causes some problems.
If the apertures in the magnet are to be formed after the ferrite plate has been sintered, either laser or mechanical drilling may be used. However, the sintered ferrite is a very hard material and forming the apertures by this technique will be a costly and lengthy process—unsuitable for a manufacturing process.
Therefore, preferably holes could be formed in the ferrite at the green state before sintering by known punching/drilling methods typical of multi-layer ceramics for microelectronics applications. However, during sintering a number of problems would be anticipated, such as, for example:
The magnet plate will be subject to uneven shrinkage leading to the holes “moving”—an unequal radial displacement from their nominal positions;
The magnet itself is likely to “bow” such that it forms a section of a large diameter sphere;
Cracking is likely to occur between adjacent apertures due to the apertures acting as stress concentrators; or
If, to obtain the desired aperture length, multiple thin sheets are stacked on top of one another, misalignment may occur in stacking which could lead to no “line of sight” through the apertures.
A further problem is that ferrite is a hard but not a tough material, and the presence of the apertures significantly reduces the mechanical strength of the plate. Thus, during shipment when large shocks may be encountered, complete mechanical failure of the magnet is a distinct possibility.
Hence, it may be necessary to use metal carriers both for mechanical strength and hole positional accuracy. In such a situation, the high temperature stability of the metal carrier materials of choice in the oxidizing sintering ambient needed for ferrite sintering dictates that the sintering temperatures of these materials to below about 1,000° C. or even lower. Similarly, the inventive sintering aids for these ferrites also need to produce a dense ferrite with coefficient of thermal expansion (CTE) of about 10×10 −6 /° C. The sintering aids should be such that they do not degrade the magnetic properties of the ferrites.
However, typical sintering temperature for Barium or Strontium or Ba—Sr ferrites is above 1300° C., therefore efforts have to be made to reduce the sintering temperature or develop materials that will meet the requirements of such applications.
U.S. Pat. No. 4,138,236 discloses a method of bonding hard and/or soft magnetic ferrite parts with an oxide glass. The oxide glass may be applied prior to or after pre-firing or main firing. Finally, the ferrite parts are fused at temperatures in excess of the glass softening point.
U.S. Pat. No. 4,540,500 discloses a low temperature sinterable oxide magnetic material prepared by adding 0.1 to 5.0 percent by weight of glass to ferrite. In some situations, the sintering temperature can be reduced to about 1,000° C. or less.
U.S. Pat. No. 4,023,057 discloses a compound magnet for a motor stator having a laminated structure that includes thin, flexible magnets made from permanently magnetizable particles, such as barium ferrite, that are embedded in a flexible matrix, such as rubber. Various laminated arrangements are contemplated for producing more intense magnetic fields and thin metal spacers are used in most laminated structures to collapse the respective fields of the flexible magnetic components to increase the flux density at the resultant poles and to orient the permanent magnetic fields in the magnetic circuit of the motor.
Published Japanese Patent Application No. JP60093742 discloses a display having a focus electrode with a conductive magnetic body and a sputtered metal coating on one surface of the magnet body. The conductivity is required for the focusing electrode to perform its function. The coating is sputtered and so is a thin coating, not substantially adding to the mechanical structure of the magnet. Each of the holes in the magnet has a number of electron beams passing through it.
U.S. Pat. No. 5,932,498, (Beeteson, et al.), issued on Aug. 3, 1999, entitled “MAGNET AND METHOD FOR MANUFACTURING A MAGNET”, assigned to International Business Machines Corporation, Armonk, N.Y., USA, the assignee of the instant Patent Application and the disclosure of which is incorporated herein by reference, discloses a magnet-photosensitive glass composite and methods thereof.
U.S. Pat. No. 5,857,883, (Knickerbocker et al.), entitled “Method of Forming Perforated Metal/Ferrite Laminated Magnet”, assigned to International Business Machines Corporation, Armonk, N.Y., USA, the assignee of the instant Patent Application and the disclosure of which is incorporated herein by reference, discloses a process for fabrication of a large area laminate magnet with a significant number of perforated holes, integrated metal plate(s) and electrodes for electron and electron beam control.
PURPOSES AND SUMMARY OF THE INVENTION
The invention is a novel low temperature sintering aid for ferrites and process for metal/magnetic-ceramic laminate with through-holes.
Therefore, one purpose of this invention is to provide a low temperature sintering aid for a magnetic-ceramic and a process that will form metal/magnetic-ceramic laminate.
Another purpose of this invention is to provide a low temperature sintering aid for a magnetic-ceramic and a process that will provide metal/magnetic-ceramic laminate with through-holes.
Yet another purpose of this invention is to use the metal/magnetic-ceramic laminate as a mask to create an image on at least one glass plate to form multi-phosphors (red, green, blue) material which receives an electron beam to create a display.
Still another purpose of this invention is to provide a low temperature sintered ferrite structure through which one or more collimated beam(s) of electrons can be formed using the ceramic/magnetic laminate.
Yet another purpose of this invention is to provide a low temperature sintered ferrite structure that can be used with any electron sensitive process.
Still yet another purpose of the invention is to provide a laminated metal/magnetic-ceramic that has a plurality of openings for guiding electrons and/or electron beams.
Still yet another purpose of the invention is to have a sintering aid in metal/magnetic-ceramic structure to allow lower temperature sintering.
Therefore, in one aspect this invention comprises a process of forming unsintered metal/ferrite laminate magnet, comprising:
(a) forming at least one opening in an metal sheet having a first surface and a second surface,
(b) securing at least one dielectric layer to at least a portion of said first surface of said metal sheet,
(c) securing at least one ceramic magnet layer containing at least one low temperature sintering aid to at least a portion of said at least one dielectric layer,
(d) forming at least one opening through said ceramic magnet layer and said dielectric layer, such that at least a portion of said opening overlaps at least a portion of said opening in said metal sheet, and thereby forming said unsintered metal/ferrite laminate magnet.
In another aspect this invention comprises a ceramic-metallic magnet comprising at least one ceramic-magnetic sheet, wherein said sheet has at least one low temperature sintering aid.
In still another aspect this invention comprises a ceramic-metallic magnet comprising at least one ceramic magnet sheet, wherein said sheet has at least one low temperature sintering aids and at least one adhesion promoter to form a metal-to-magnetic-ceramic layer adhesion.
In yet another aspect this invention comprises a process of forming unsintered metal/ferrite laminate magnet, comprising:
(a) forming at least one first opening in an metal sheet having a first surface and a second surface,
(b) securing at least one dielectric layer to at least a portion of said first surface of said metal sheet,
(c) securing at least one ceramic magnet layer containing at least one low temperature sintering aid to at least a portion of said at least one dielectric layer,
(d) forming a second opening using said first opening as a guide, such that at least a portion of said second opening overlaps at least a portion of said first opening in said metal sheet, and thereby forming said unsintered metal/ferrite laminate magnet.
In still yet another aspect this invention comprises a process of forming a sintered metal/ferrite laminate magnet, comprising:
(a) forming at least one opening in an metal sheet having a first surface and a second surface,
(b) securing at least one dielectric layer to at least a portion of said first surface of said metal sheet,
(c) securing at least one ceramic magnet layer containing at least one low temperature sintering aid to at least a portion of said at least one dielectric layer,
(d) forming at least one opening through said ceramic magnet layer and said dielectric layer, such that at least a portion of said opening overlaps at least a portion of said opening in said metal sheet, and sintering the same to form said sintered metal/ferrite laminate magnet.
In still another aspect this invention comprises a process of forming a ceramic-metallic magnet, comprising mixing at least one ceramic material, at least one metallic material and at least one low temperature sintering aid and sintering said mixture at a temperature of between about 400° C. and about 1000° C.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The drawings are for illustration purposes only and are not drawn to scale. Furthermore, like numbers represent like features in the drawings. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:
FIG. 1, illustrates a preferred embodiment of this invention where at least one magnetic-ceramic laminate directs at least one electron beam from a cathode.
FIG. 2, illustrates a cross-sectional view of a ceramic-magnetic plate made according to the teachings of this invention.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, there is provided an electron source comprising at least one cathode means and at least one magnetic-ceramic, sintered at lower temperature with use of sintering aids and laminated with grid electrodes. The magnets are perforated by at least one channel extending between opposite poles of the magnet, wherein each channel in the magnet can direct or guide electrons received from the cathode means into an electron beam towards a target with no possible overlap.
In a preferred embodiment of the present invention, the electron source comprises grid electrode means disposed between the cathode means and the ceramic magnets which were sintered using low temperature sintering aids, for controlling flow of electrons from the cathode means into the magnetic channels.
The magnetic channels are preferably disposed in the ceramic magnet in a two dimensional array of rows and columns. However, a person skilled in the art could also customize the dimensional array.
Preferably, the grid electrode means comprise a plurality of parallel row conductors and a plurality of parallel column conductors arranged orthogonally to, and insulated from, the row conductors, each channel being located at a different intersection of a row conductor and a column conductor.
The grid electrode means may be disposed on the surface of the cathode means facing the magnet. Alternatively, in the present invention the grid electrode means may be disposed on the surface of the magnet and sintered using low temperature sintering aids and facing the cathode means.
The laminate with magnet(s) preferably comprises ferrite. In some embodiments of the present invention, the magnet may comprise a ceramic material. In other embodiments of the present invention, the magnet may also comprise a binder. The binder may be organic or inorganic. Preferably, the binder comprises an inorganic glass composite, containing glass forming oxides for optimized properties in fabrication and use.
The present invention also extends to display devices and a computer system comprising: memory means; data transfer means for transferring data to and from the memory means; processor means for processing data stored in the memory means; and a display device comprising the electron source as hereinbefore described for displaying data processed by the processor means.
It will further be appreciated that the present invention extends to a print-head comprising an electron source as hereinbefore described. Still further, it will be appreciated that the present invention extends to document processing apparatus comprising, such as, a print-head, together with means for supplying data to the print-head to produce a printed record in dependence on the data.
The present invention in another embodiment is a triode device comprising: cathode means; a magnetic laminate perforated by at least a channel extending between opposite poles of the magnet wherein each channel forms electrons received from the cathode means into an electron beam; co-sintered grid electrode means disposed between the cathode means and the magnet for controlling flow of electrons from the cathode means into the channels; and, anode means disposed on the surface of the magnet remote from the cathode for accelerating electrons through the channels towards the glass plate containing phosphors.
The present invention is also a process for making an electron beam collimator, comprising: forming perforated metal plates, perforated green sheets of dielectric and ferrite with low temperature sintering aids containing compositions, forming metal electrode conductors and composite magnetic structure to produce a laminate with desired characteristics.
The process may comprise mixing the ferrite with low temperature sintering aids and with a binder prior to forming the magnetic structure. Preferably, the binder comprises glass particles.
The process may also comprise depositing anode means on a perforated face of the magnet(s).
Preferably, the process comprises control grid means on the face of the laminate remote from the face carrying the anode means.
At least one of the steps of forming the anode means and the steps of forming the control grid means may comprise photo-processing or chemical etching. Alternatively, plating, screen printing or decal transfer may be used for depositing anode means and control grid means.
The present invention could also be a process for making a display device comprising: making an electron source according to the process hereinbefore described; positioning a phosphor coated screen adjacent to the face of the magnet carrying the anode means; and, evacuating spaces between the cathode means and between the magnet, sintered at lower temperature using sintering aids, and the magnet and the screen.
The present invention could also be a process for addressing pixels of a display screen having a plurality of pixels, each pixel having successively first, second, and third sub-pixels in line, the process comprising: generating a plurality of electron beams, each electron beam corresponding to a different one of the pixels; and, deflecting each electron beam to repetitively address the sub-pixels of the corresponding pixel in the sequence second pixel, first pixel, second pixel, third pixel.
Referring now to the figures, such as, FIG. 1, a magnetic matrix display (MMD) 100 , of the present invention is shown which comprises, a first or lower plate 10 , such as, a glass plate 10 , having at least one cathode 12 , and a second or upper plate or screen 20 , such as, a glass plate 20 , having at least one coating of at least one phosphor pixel or dots or stripes 21 . It is preferred that the phosphor coatings 21 , are sequentially arranged red, green and blue phosphor coatings 21 , facing the cathode 12 . The phosphor coatings 21 , are made from preferably high voltage phosphors. At least one anode layer 22 , is disposed on or adjacent to the phosphor coating 21 .
At least one composite magnetic plate or sheet 90 , preferably made of ferrites with low temperature sintering aids, is disposed between the plates 10 and 20 . The composite magnetic sheet 90 , has a first or lower surface electrode 91 , and an upper or second surface electrode 93 , having a ceramic magnet layer 92 , is perforated by a two dimension matrix of perforation or “pixel wells” 23 . Electron beams 14 , are channeled through the “pixel wells” 23 . At least one bias 15 , which is preferably near or on the first electrode 91 , can be used to channel the electrons in the electron beam 14 . A housing 25 , contains and protects the different components of the MMD 100 .
As stated earlier that typical sintering temperature for Barium or Strontium or Ba—Sr ferrites is above 1300° C., therefore those types of material would degrade this invention. Therefore, one has to find materials that would meet the needs of this invention, such as, a ferritic material which has a reduced sintering temperature. To obtain such materials one could involve liquid phase sintering (using sintering additives that will form a liquid phase around the required temperature), activated sintering (using additives in very low concentration that will improve the sintering kinetics), or increasing the sintering force by substantially reducing the ferrite particle size. After some analysis it seems that the first approach is the most versatile. The liquid phase forming systems can be binary or ternary oxide systems with eutectic compositions having melting points well below the required sintering temperature. For some applications it is possible to have more than three component systems, but it would be at the expense of more complicated phase equilibria considerations. However, there is a family of low melting binary or ternary oxide systems. Therefore, it is possible to choose low melting additive system(s) with neutral or benevolent chemical interactions with the ferrites. A neutral liquid phase sintering additive system will create a liquid well below the sintering temperature that will wet all the ferrite particles efficiently (close to zero contact angle), and densification of the particulate matrix through particle rearrangement, and solution/re-precipitation mechanisms, with very limited chemical interaction with the ferrite particles. However, a large volume fraction of such additives reduces the magnetic moment of the resulting matrix even if 100% densification is achieved. Similarly, a sintering additive system with benevolent interaction could react with the ferrite particles during the densification and potentially form ferrites of similar type and magnetic properties. This type of additive system allows one to add large amount of sintering additives (up to 20% by volume) without affecting the magnetic properties of the sintered body substantially. Thus the present invention takes advantage of both of these approaches to develop low temperature sintering additives for ferrites.
FIG. 2, illustrates a cross-sectional view of a ceramic-magnetic plate 92 , made according to the teachings of this invention, wherein the plate 92 , has at least one low temperature sintering aid as one of the constituents of the plate 92 .
As stated earlier, that in order to form the ceramic-magnetic layer 92 , it is preferred that the right sintering aid candidates involve (a) choosing eutectic oxide liquid phases with melting point around or below 800° C., and (b) choosing oxide systems that will have at least one component of the ferrite matrix (Ba, Fe or Sr), and/or at least one ferrite forming component (Cu, Ni, Zn, etc.). This would ensure good wetting of the matrix powder particles (ferrites) by the liquid phase to give fast densification and also lead to little or no degradation of the magnetic properties once the densification has been completed (due to ferrite forming liquid).
A number of inventive sintering aid systems have been found to meet the above-mentioned criteria. These included mixtures of oxides of barium and copper (BaO—CuO), oxides of strontium and copper (SrO—CuO), oxides of copper and tellurium (CuO—TeO 2 ), oxides of bismuth and copper ( Bi 2 O 3 —CuO), oxides of magnesium and tellurium (MgO—TeO 2 ), oxides of bismuth and strontium ( Bi 2 O 3 —SrO), oxides of strontium and tellurium ( SrO—TeO 2 ), oxides of strontium and vanadium pentoxide (SrO—V 2 O 5 ), oxides of strontium and molybdnum (SrO—MoO 3 ), oxides of iron and vanadium (Fe 2 O 3 —V 2 O 5 ), oxides of bismuth and zinc (Bi 2 O 3 —ZnO), oxides of bismuth and nickel (Bi 2 O 3 —NiO), oxides of bismuth and magnesium (Bi 2 O 3 —MgO) etc. and some of their ternary combinations. However, the preferred low temperature sintering aids are the eutectic compositions in mixtures of Bi 2 O 3 —ZnO, Bi 2 O 3 —NiO, and Bi 2 O 3 —CuO.
The eutectic composition additives of this invention were prepared by first mixing the individual oxides in correct proportions (obtained from the phase diagrams), the oxide mixtures were then calcined at temperatures of between about 0.6 to about 0.8 Tm (where Tm is the eutectic melting temperature in the system expressed in degree Kelvin). The calcination step was repeated once or twice (depending on the system), until a homogeneous eutectic mixture was obtained, and that there were no unreacted components remaining. The calcined mass was then ball-milled to reduce the particle size until there were no particles over about 20 microns. These sintering additive powders were then used, for example, about 10% by wt., for example, with Ba-Ferrite powder, and then ball milled for homogeneity. The Ba-Ferrite powders obtained with the sintering additives were subsequently used for making the ceramic-magnetic layer 92 , using low temperature sintering.
Different combinations were used to make the ceramic-magnetic layer 92 , of this invention, and it was discovered that it is possible to obtain better than 96% density by sintering at around 980° C., for example, for about 4 Hr, for all of the three preferred systems, namely Bi 2 O 3 —ZnO, Bi 2 O 3 —NiO, and Bi 2 O 3 —CuO. Similar densities were also obtained with sintering the compositions for the ceramic-magnetic material 92 , at around 880° C., however, the sintering time had to be increased, for example, to about 12 Hr.
Further improvements in the formation of the ceramic-magnetic layer 92 , could also be made by adding, for example, about 5% by wt. of Cr 2 O 3 and/or TiO 2 , to promote metal to magnetic-ceramic adhesion during sintering.
Data on magnetic hysterisis for such low temperature sintered magnetic-ceramic material 92 , was obtained using SHE SQUID magnatometer, and it clearly showed that the coercive field Hc of above 3100 gauss could be obtained using these sintered materials.
Metal/magnetic-ceramic laminate 90 , could also be obtained by forming at least one opening 23 , in a metal sheet and securing at least one non-magnetic dielectric layer, and/or at least one ferrite with low temperature sintering additives layer, to the metal sheet. One could then form at least one opening 23 , in the dielectric layer and/or the ferrite layer, such as, by punching. The opening 23 , would correspond to at least one opening 23 , in the secured metal sheet to obtain an unsintered sub-laminate structure. One could then sinter the metal/dielectric/ferrite layer assembly with holes to full densification. One could subsequently build metal electrodes on the top and bottom surfaces of the sintered laminate.
While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention. | The present invention relates generally to a new metal/magnetic-ceramic laminate with through-holes and process thereof. More particularly, the invention encompasses a new process for fabrication of a large area ceramic laminate magnet with a significant number of holes, integrated metal plate(s) and co-sintered electrodes for electron and electron beam control. The present invention also relates to a magnetic matrix display (MMD), and electron beam source, and methods of manufacture thereof. | 8 |
DESCRIPTION
This application is a continuation in part of U.S. Ser. No. 08/008,614, filed on Jan. 22, 1993, now abandon.
This invention relates to an article for animals entertainment, particularly intended for pets.
It is a well-known fact that animals often like to play with objects of all kind that they may retrieve, using them for their entertainment.
In the specific instance of pets, specifically dogs and cats, they usually like to play with discarded household objects, as their owner may intentionally or casually have set them aside for this use. These objects, following prolonged use, may even become familiar with animal, such that the animal often grow attached to them.
It is an object of this invention to provide an entertainment article of the kind outlined above, which is so designed and structured as to be specially attractive for the animal to whom it is aimed.
According to the present invention, this object is achieved by an article as specified above and characterized in that it is basically composed of a plastic material based on natural, biodegradable polymers.
Preferred materials for the articles include starch, starch hydrolyzate or destrines and blends thereof with substantially biodegradable thermoplastic polymers either synthetic or natural, particularly biodegradable ethylene copolymers.
The preferred materials are thermoplastic blends obtained by processing starch and said thermoplastic polymers in the presence of a limited amount of water (10-40% wt. referred to the starch/water system) or of a polyol plasticizer (10-40% wt. referred to the starch/polyol system), under extrusion cooking conditions thereby to provide a melt to be extruded and transformed into pellets for use in injection moulding or to be directly injection moulded.
Preferred polymers to be blended with starch include poly-ethylene-vinylalcohol and poly-ethylene-acrylic acid. The weight ratio of said polymers and starch (natural starch being preferred) is generally comprised within the range 1:6 to 2:1; higher amounts of starch are preferred so that the preferred relative ratio is from 1:6 to 1:1.
Preferred plasticizers, which are preferably used in combination with a small amount of water such the intrinsic water content of starch (5-15% wt.), include edible polyhydric alcohols such as particularly glycerol, sorbitol, sorbitan, mannitol, maltitol, hydrogenated starch syrup, sucrose, maltose and fructose.
The composition may further include edible lubricants comprising mono-, di-, and tri-esters of edible polyhydric alcohols, such as those mentioned above, with edible higher fatty acids, such as stearic acid, oleic acid, linoleic acid, linolenic acid, palmitic acid and lauric acid. Other lubricants include phospholipids, such as lecithine and phosphoric acid derivatives of the above-mentioned esters.
Biodegradable blends suitable for use in the present invention are described in EP-A-0 400 532, incorporated herein by reference.
Further features and advantages of this invention will be more clearly apparent from the following detailed description of the embodiment thereof given by way of example and not of limitation, with reference to the appended drawing.
The figure illustrates a bone-like article according to the invention.
With reference to the drawing, an article--according to the invention--is generally shown at 1 and has the appearance of a bone that may be commonly given to dogs.
This bone-like article is formed from a edible support material as previously described; in a preferred embodiment of the invention, a material commercially known as MATER-BI and manufactured by Novamont company is used.
An article for animals entertainment, according to this invention, affords a great number of advantages.
In the embodiment just described, the article has a shape with which the addressed animals, presently a dog, is likely to be familiar with and into which the animal would rather bite like in any other item of this standard diet. In fact, the entertainment article of this invention could advantageously be provided with a shape of a food item that may appeal to the animal and, therefore, even with the shape of piece of meat where a dog is involved.
Further, the plastics with which the bone is formed has an alluring smooth appearance, is odourless in its normal state and has proved to be exceedingly attractive for animal species on which it has been tested. The articles made from the above-described plastics material are substantially water insoluble, although they are susceptible to swell somewhat in water.
It has surprisingly be found that the aforesaid preferred plastics can be easily digested by the animal, and if shattered do not produce sharpened fragments that could be harmful for the animal.
Another advantage of this invention resides in that the plastics material can be processed into the final article, using standard methods and equipments conventionally employed in plastics processing art. This enables the entertainment article to be formed in any shape and size. Further, the aforesaid plastics may be processed into a porous structure whereby any desired additional substance can be associated with the article to enhance its quality. Such would be the case, for instance, of nourishing integrative substances such as vitamins, proteins, mineral salts or flavouring substances or therapeutical substances such as fluorine or fluorine containing compounds suitable for dental care or any substance effective to enhance the attractiveness of the article for the intended animal.
Therefore, it should be emphasized that depending on the application for which the article of this invention is intended, that is either domestic of wild animal species the same can be made in different forms. As an example, where a cat is involved, it could be made in the shape of a fish or a small mouse or any other item of food associated with this animal. | A chew toy for animals is molded into the shape of a familiar animal food item, such as a dog bone, from a polymer composition which is both edible and degradable. The composition is essentially comprised of a starch material and a degradable ethylene copolymer, preferably poly-ethylene-acrylic acid or poly-ethylene, vinylalcohol. The preferred weight ratio of the ethylene copolymer and the starch material is within the range of about 1:1 to 2:1. Plasticizers and edible lubricants can also be added to the composition. | 0 |
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