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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 146,213, filed May 5, 1980, now abandoned as of the filing date of this application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to apparatus for removal and replacement of mortice locks and similar locking structure with minimal damage to the lock. In particular, the invention relates to wrench structures which allow rapid removal of the cylinder of a mortice lock without damage to the keyway.
2. Description of the Prior Art
Mortice and mortice thumbturn locks, as well as similar locking apparatus, are widely used, particularly in metal doors such as are common in commercial buildings including motels, hotels, stores, and the like. The mortice lock includes a cylinder which is held in the door by a set screw or cylinder yoke. From time to time, such locks need to be replaced for differing reasons. Various tools have previously been employed by the locksmith to remove such locks. These prior tools, which include pliers, vice grips, pipe wrenches, etc., unfailingly causing damage to and mar the edges of the lock face. These previous practices typically have resulted in the need for replacing the complete cylinder and, in many instances, the keyway itself which is expensive and often difficult to obtain since many such keyways are master keyed or otherwise keyed to form a part of a series of locks. Accordingly, in situations where mortice locks are to be removed, replaced or installed, it is desirable not only to cause as little cosmetic damage to the lock as possible, but it is also necessary to prevent damage to the keyway due to the expense and difficulty of obtaining a new keyway or core which would have a pin setting compatible with locks already in place in a building or series of buildings. The present invention provides apparatus capable of removing and replacing standard mortice cylinder locks with minimal damage to the lock face and without damage to the core or keyway of the lock. Apparatus provided according to the invention includes wrench structures which fit about the face of the cylinder of the lock to allow the cylinder to be loosened even in situations where the cylinder threads are crossed or the cylinder is corroded. Use of the invention is facilitated by drilling of the lock to cut away the set screw or yoke, the wrenches of the invention being then particularly useful to remove the cylinder from an installed position. Further, the present wrench allows a new mortice lock to be rapidly installed with a minimum of effort and without damage, either cosmetic or otherwise, to the lock.
SUMMARY OF THE INVENTION
The present invention provides particular apparatus which is useful for removing and replacing standard mortice cylinder or mortice thumbturn locks both rapidly and without damage to the keyway or core of the lock. The invention can be used with a template structure or drill jig which fits over the face of the lock and allows exact positioning of a drill so that the end of a set screw holding the lock in a door can be cut away without damage to the keyway core of the cylinder, thereby saving the usually restricted and often difficult to obtain key way so that the same pin setting can be reused in order to be compatible with other cylinder locks which are similarly keyed. A drill template such as can be efficaciously used with the present wrench structures is disclosed in now abandoned U.S. patent application Ser. No. 146,213, of which the present patent application is a continuation-in-part and in U.S. patent application Ser. No. 337,840 which is a divisional of abandoned U.S. patent application Ser. No. 146,213. This drill template has a first aperture extending normally therethrough to allow use with cylinders such as the Medeco rim cylinder. A second aperture disposed on the other side of a central slot disposed in the template is angled for use with certain other mortice lock cylinders.
Once the head of the set screw has been cut away through the use of the drill template as aforesaid, wrench structures configured according to the present invention can be used to remove the mortice cylinder even though the threads of the cylinder may be crossed or the cylinder corroded. The present wrenches can be used both to remove and to install a cylinder. In situations where the set screw is already broken, the present wrenches can be solely used to remove the cylinder lock. It is even possible to use the present wrench structures on a cylinder lock, particularly a pick-resistant cylinder lock, to break the set screw without prior drilling. In all situations, the present wrench structures allow removal or installation of the cylinder lock without marking the edge of the lock face such as occurs when a pipe wrench or similar piece of equipment is used in a crude effort to remove such a lock. Further, use of the present apparatus reduces the time necessary for lock removal and installation and reduces the possibility of damage to the lock keyway.
Accordingly, it is an object of the invention to provide apparatus for removing and replacing a standard mortice cylinder or mortice thumbturn lock with a minimum of damage to the lock face and without damage to the keyway core of the lock, thereby enabling the reuse of the pin setting.
It is another object of the invention to provide a wrench structure which allows rapid and safe removal of a mortice cylinder from a door either with or without prior removal of a set screw head of a cylinder yoke holding the cylinder in the door, the present wrench being particularly useful when the threads of the cylinder are crossed, when the cylinder is corroded, or when the screw head is broken.
Further objects and advantages of the invention will become more readily apparent in light of the following detailed description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a wrench configured according to the present invention, the wrench being shown in position over a lock cylinder during removal or installation of the lock;
FIG. 2 is a perspective view of a wrench configured according to the present invention and being particularly configured to utilize a lock key to serve as a fulcrum during removal and installation of the lock;
FIG. 3 is a perspective view from the underside of a wrench configured according to a second embodiment of the present invention and wherein the wrench is configured to accept a thumbturn to act as a fulcrum during removal and installation of a mortice lock; and,
FIGS. 4a and 4b are schematic views illustrating contact between a wrench, key and lock in certain useage modes.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly to FIGS. 1-3, two embodiments of a cylinder wrench 10 configured according to the invention are shown. The wrenches 10 are configured to act in concert with a drill template such as is disclosed in now abandoned U.S. patent application Ser. No. 146,213 of which the present patent application is a continuation-in-part and in U.S. patent application Ser. No. 337,840 which is a divisional of abandoned U.S. patent application Ser. No. 146,213. This drill template is useful to facilitate cutting away of a set screw of a cylinder yoke in a mortice lock or similar lock to facilitate removal and replacement of such a mortice lock. As particularly seen in FIG. 1, the cylinder wrench 10 is seen in a use situation to be disposed over the lock 12 which has been drilled to remove a holding set screw through use of a drill template such as is referred to above. Once the structure which positively holds the lock 12 within the door or other installation has been removed, the wrench 10 is utilized to rotate the lock 12 out of the door. The wrench 10 is thus used to manually "unscrew" the lock 12 from the door when said lock is to be removed. Conversely, the wrench 10 is also used to screw a replacement lock into place within the door. The cylinder wrench 10 is particularly useful in those situations where the threads of the cylinder lock are crossed or the cylinder has become corroded in the door. The wrench 10 can also be used as described without damaging the cylinder or marring the edge of the lock face. Removal of the lock 12 without damage to the lock case is particularly important, such damage requiring replacement of the complete cylinder and often resulting in damage to the keyway or core of the lock.
As particularly seen in FIGS. 1-3, the wrench 10 is seen to comprise an annular body member 14 having a handle 16 attached thereto. The handle 16 is preferably formed of flat steel stock which is angularly bent at 18 and 20, anterior portion 22 of the handle 16 being substantially parallel to distal portion 24 which contacts the annular body member 14. The distal portion 24 is seen to be slotted in FIGS. 2 and 3, the wrench 10 of FIG. 2 having a slot 26 which is essentially 0.11 inch wide while the wrench 10 of FIG. 3 has a slot 28 which is approximately 3 times greater in width than the slot 26. As will be seen also in FIGS. 4a and 4b, the slot 26 is sized to accept the outwardly extending portion of a key 30 therethrough when the wrench 10 is located over a cylinder lock which is to be removed or installed. The key 30 serves as a fulcrum for operation of the wrench 10 of FIGS. 1 and 2 and a portion of the inner surface of the slot 26 engages a surface portion of the key 30 as seen in FIGS. 4a and 4b. At least a portion of inner surface 32 of the annular body member 14 also abuts opposite portions of the circular outer edge surface of the cylinder of the mortice lock 12 to provide the additional contact necessary to rotate the lock 12. While the inner diameter of the annular body member 14 can be sized to be only slightly greater than the outer diameter of the lock 12, such that a substantially flush fit can occur therebetween, it is preferred that the inner diameter of the annular body member 14 be sufficiently greater than the outer diameter of the lock 12 such that a clearance exists therebetween when the annular body member 14 is centered on the lock 12. Choosing the inner diameter of the annular body member 14 to be greater than standard Medeco locks serves at least in part to allow the wrench to fit over various locks of differing size. Further, this clearance allows the wrench 10 to be manipulated to best advantage about the fulcrum provided by the key 30 (or a thumbturn for the wrench of FIG. 3) to engage a localized portion of the circular outer edge surface of the lock cylinder with an opposing portion of the inner surface 32 while simultaneously engaging a portion of the inner surface of the slot 26 with an opposing surface of the key 30, thereby to provide bearing engagement between the wrench 10 and both the key 30 and the cylinder of the lock 12. Accordingly, the mechanical advantage necessary to rotate the lock 12 on rotation of the wrench 10 is provided. While the extent of the fitting of the inner surface 32 against the outer edge surface of the cylinder of the mortice lock 12 may vary depending upon the relative diameters of the annular body member 14 and of the lock 12, a bearing engagement is thus provided therebetween and need only be an essentially tangential contact. This contact between the inner surface 32 of the annular body member 14 and the lock cylinder can be varied by the user of the wrench 10 and can be located virtually oppositely across from the key 30 or on a portion of the circular outer edge surface of the lock cylinder which is essentially adjacent to the key 30. In effect, however, the dual engagement afforded by contact and bearing engagement between two portions of the wrench 10 and both the key 30 (or blank) or thumbturn (not shown) and a portion of the circular outer edge surface or equivalent structure of the lock 12 is necessary to facilitate rotation of the lock 12. The use simply of a wrench with an annular body member which fits flushly over a lock cylinder without the necessary mechanical advantage which is provided according to the invention is not sufficient to rotate the lock.
It is to be particularly noted that the key 30 can take the form of a key blank or cut key inserted into the keyway of the lock 12. In all such situations, a portion of the inner surfaces 32 of the slot 26 bears against an opposing portion of the key 30 to provide mechanical advantage necessary to rotate the lock 12. Any attempt to use the mechanical advantage solely provided by this contact between the key 30 and the inner surfaces 32 of the slot 26 may result in the breaking of the key 30. The operation of the wrench 10 as thus described above is accordingly advantageous.
The slot 28 of the wrench 10 of FIG. 3 is seen to be sized to similarly fit over a thumbturn (not shown) of a similar mortice lock, the thumbturn serving as a fulcrum to provide bearing surfaces to obtain mechanical advantage in the same manner as does the key 30.
While the cylinder wrenches 10 are particularly intended to be used to remove and replace a lock such as the lock 12 after drilling of the lock with a template as aforesaid, it is possible to utilize the wrenches 10 solely, particularly on cylinders which are pick-resistant, the mechanical advantage afforded by the wrenches 10 being often sufficient to break the set screw without drilling of the lock. Accordingly, the wrenches 10 can be rapidly used to remove even a cross-threaded or corroded lock without marking the edges of the lock face or otherwise damaging the cylinder case or keyway of the lock. In such situations, the set screw or yoke holding the cylinder from the edge of the door acts to break the set screw or yoke without breaking of the blank or cut key 30. Cylinders which are difficult to remove can be readily handled through use of the present wrenches 10 even though such a cylinder be provided with hardened collars. As is apparent from the foregoing, the wrenches 10 can also be used to install a lock by rotating the new lock in a counter-clockwise direction opposite to that required for removal of a lock.
It is believed apparent that the concepts explicitly illustrated herein can be practiced other than as expressly described without departing from the scope of the invention. Accordingly, the invention is intended to be understood in light of the description provided herein, but is to be properly limited in scope only by the recitations of the appended claims.
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Apparatus for removing and replacing a standard mortice cylinder or mortice thumbturn lock, the invention includes particular wrench structures for removing a mortice lock which has been drilled in order to cut away the set screw or cylinder yoke holding the cylinder in the door or other structures in which the lock is installed. The present wrench structures are also useful for removal of the mortice cylinder when the threads of the cylinder are crossed, when the cylinder is corroded, or when the screw head is broken. The present structures particularly allow removal and installation of mortice locks and similar locking apparatus with minimal damage to the lock face and without damage to the keyway, the expensive keyway thus being reuseable.
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BACKGROUND OF THE INVENTION
This invention relates to feed systems for electric arc smelting furnaces and more particularly to a feed system which permits delivery of feed material to chutes distributed around the roof of an electric arc smelting furnace.
Electric arc furnaces are employed for smelting the ores of various substances, such as nickel, phosphorous, silicon and the like. Such furnaces generally comprise a furnace hearth and an arched roof through which one or more electrodes extend. The heat necessary to promote the chemical reactions required for the smelting process is generated by electric arcs struck between the electrodes or between the electrodes and the furnace charge. During the smelting process, it is necessary to charge additional materials, such as coke or the like, into the furnace. Conventional furnaces may include one or more feed hoppers coupled to chutes which extend through the furnace roof. In this manner, material may be charged into the furnace from time to time.
Prior art systems for charging materials into smelting furnaces tended to deliver the material to a few locations. Other systems which included a plurality of feed chutes distributed around the furnace roof included a plurality of belt type conveyors running from a distribution hopper to each of the feed chutes.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a new and improved feed system for smelting furnaces.
Another object of the invention is to provide a feed system for smelting furnaces which permits the delivery of material to plural feed chutes extending from the furnace roof with a single conveyor.
Another object of the invention is to provide a feed system for smelting furnace which does not require multiple transfer points and which is functional in low head room conditions.
A further object of the invention is to provide a feed system for electric arc smelting furnaces which may be used with a wide range in the number of feed chutes.
Yet another object of the invention is to provide a feed system for electric arc smelting furnaces which is simpler and less costly than prior art systems.
A still further object of the invention is to provide a feed system for electric arc smelting furnaces which requires less power for operation than prior feed systems.
These and other objects and advantages of the invention will become more apparent from the detailed description thereof taken with the accompanying drawings.
In general terms, the invention comprises a feed system for a treatment furnace having a plurality of feed receiving means disposed in a generally circular array for receiving feed materials and delivering the same to spaced apart locations within the furnace. The feed system includes a transporter mounted adjacent the furnace for movement in an arcuate path having a center of curvature coincident with the circular array of the feed receiving means and conveying means mounted on the transporter and movable thereon in a generally horizontal, arcuate path coincident with the center of curvature. Feeding means are disposed adjacent the arcuate path of the conveying means for depositing materials thereon. The conveying means includes an arcuate center portion and end portions on the support means defines a transition in the direction that the conveyor belt means moves so that the material deposited on the belt means will be translated to the discharge means and discharged from the belt means. The support means is rotatable about the axis of curvature of the path that the conveyor belt means moves whereby the discharge means may be selectively positioned adjacent each of the material receiving means so that material deposited on the conveyor belt means may be discharged into selective ones of the receiving means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of an electric arc furnace roof upon which the feed system in accordance with the present invention is installed;
FIG. 2 is a side elevational view, partly in section of the feed system according to the present invention; FIGS. 3 and 4 are fragmentary views of the apparatus shown in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an arc furnace roof 10 upon which the conveyor system 12 of the invention may be mounted. Those skilled in the art will appreciate that smelting furnace roofs are normally arched and that a dished furnace hearth (not shown) is disposed below the roof for receiving the furnace charge. The hearth and roof each normally include a metallic shell and a refractory lining whose chemical composition is dictated by the material being treated. Extending through openings in the furnace roof 10 are a plurality of electrodes 14. While three electrodes arranged in a triangular array are shown, it will be appreciated that the invention has application to furnaces having any number of electrodes or electrodes which arranged differently. Those skilled in the art will also appreciate that the electrodes 14 will normally be of a graphite material and may be self baked or precast. Also, each electrode is normally supported by an electrode positioning and slipping apparatus which is not shown, but is well known in the art.
Also extending through the roof 10 are a plurality of feed chutes 16 which are arranged in a circular array with a pair of chutes being disposed in the roof sector between adjacent the electrodes and between a circle defined by the axes of the electrodes and the outer periphery of the roof 10. While six feed chutes are shown, the invention may be employed with any number of chutes. Also, while it is preferred that the pairs of chutes and the chutes of each pair be equally spaced apart, such spacing is not essential. The conveyor system 12 generally includes a conveyor 18 which is mounted on a car 19 having an annular configuration in plan view as shown in FIG. 1, except for a gap 20. The car 19 is mounted on track means which may comprise spaced apart concentric annular tracks 22 and 24 which are supported on a platform 25 which surrounds the outer periphery of the furnace roof 10. It will also be appreciated that the car may also be mounted on a mono-rail. The car 19 includes upper and lower tracks 26 and 27 which support the conveyor belt 18. A pair of pulleys 29 and 30 are mounted at the opposite sides of the gap 20. The belt 18 passes from the lower track 27 around pulley 30 to the upper track 26 along the upper track 26, around the pulley 29 to the lower track 27. A drive 32 is coupled to the car 20 so that the latter may be sequentially stepped to place the gap 21 successively at the feed chutes 16. At one side of the furnace roof 10 is a hopper 33 for depositing a measured quantity of material on the belt 18. Premeasured materials can also be deposited directly on the belt 18 from a feed conveyor (not shown).
The car 19 includes a frame 34 and a plurality of trucks 35 which engage the tracks 22 and 24. Frame 34 consists of upper and lower arcuate sections 36 and 37 which are coupled in a parallel spaced apart relation by vertical members 39 extending therebetween. The sections 36 and 37 are substantially circular except for the gap 20 and may be fabricated in any suitable manner such as by side angle members 40 and top and bottom plates 42.
Mounted atop the upper section 36 of frame 34 is a conveyor support 44 consisting of a base 45 affixed to the upper surface of section 36 and a plurality of pairs of members 44 which extend vertically upward from the opposite sides of the base 45. While any suitable conveying or system may be employed, the illustrated embodiment with conveyor 18 includes a belt 48 and a track system 49 having an arcuate frame 50 supported between the members 47 and extending around the car 19. Mounted at the upper and lower ends of frame 50 are pairs of upper and lower spaced apart channel members 51 and 52 which define upper and lower tracks. Belt 48 is formed of a suitable flexible material and has a plurality of spaced transverse ribs 53 affixed to its lower surface. A coupler 54 is affixed to each rib 53 and engages a continuous chain 55 extending around the upper and lower ends of frame 50. In addition, spaced apart ones of the couplings 54 include a roller assembly 56 having a plurality of rollers 57 mounted on supports 58. The rollers engage the tracks 51 and 52 which extend along the upper and lower ends of the frame 50.
The pulleys 29 and 30 are contoured complimentary to the conveyor belt 48 and each is rotatably mounted between support arms 60 by means of shafts 61 and bearings 62. The arms 60 extend horizontally in spaced apart relation on the ends of the frame 50 and on the opposite sides of the gap 20. Each pulley also includes a sprocket (not shown) which engages the chain 56. One of the shafts 61 is suitably driven by a motor (not shown) for driving one pulley while the other idles.
The trucks 35 each include a pair of wheels 63 mounted on the shaft 64 rotatably received in bearing 65 supported by brackets 66 extending downwardly from the lower section 67 of car frame 34.
The drive assembly 32 includes a motor 67 mounted outwardly of the tracks 22 and 24 and coupled by a shaft 68 to a speed reducer 69. A sprocket 70 is mounted on an output shaft 71 extending upwardly from speed reducer 69 and meshes with a sprocket chain 72 mounted along the side of the car 19 and extending substantially from one end to the other. The motor output shaft 68 may also be coupled to a suitable brake, such as, magnetic brake 73.
A coupling chute 74 is also mounted on car 19 and is disposed in the gap 20. Chute 74 includes an upper funnel shaped portion 75 and a downwardly and inwardly extending tubular portion 76. The lower end of the 77 of tubular portion 75 is positioned to be in registry with the upper end of the chutes 16 which are mounted on the furnace roof.
In operation, the drive 32 sequentially steps the car 16 to position the gap 21 in alignment with the opened upper end of one of the feed chutes 16. This will place the lower of lower end 76 of the chute 72 above the opened end of one of the chutes 16 mounted in the furnace roof. The hopper 32 is then operated to place a measured quantity of feed material on the upper surface of the running conveyor 18. The pulley 29 is driven to carry the feed material to the gap 20 whereupon it is deposited in the upper portion 74 of chute 73 and flows downwardly to the feed chute 16. This process may be repeated to place measured quantities of the feed material into each of the feed chutes 16 so that the feed material is distributed over the surface of the melt disposed within the furnace hearth. It will be appreciated that the deposit of material on the conveyor 18 and the movement of the conveyor gap 20 to each feed station can be automated or manually operated.
While only a single embodiment of the invention has been illustrated and described, it is intended to be limited only to the scope of the appended claims.
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A feed system for a smelting furnace having a plurality of feed chutes arranged in a spaced apart, circular array. The feed system includes a circular conveyor mounted adjacent the furnace and concentrically with the feed chutes. The conveyor also has a gap therein which permits the discharge of material downwardly into the feed chutes and means for rotating the conveyor about its axis of curvature to sequentially position the gap above successive feed chutes. In addition, one or more feed hoppers are positioned above the conveyor for depositing feed materials thereon.
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OBJECT OF THE INVENTION
[0001] The object of the present invention is a grey water regeneration system which guarantees the quality of the water obtained for its subsequent reuse.
[0002] For this end, the system has sensors which fully control the process by means of a Pogrammable Logic Controller (PLC) that is designed to monitor, in real time, the operation in all sequential processes of each of the different devices and reservoirs of the treatment system of the invention.
[0003] The PLC is used to control and adjust the operation of the system through sensors. The system comprises at least pH sensors, suspended solid sensors, turbidity sensors, residual chlorine sensors, tank filling level sensors, level sensors for the dispensers and pressure sensors. The PLC reports these collected data to a central database, so that the control can be performed remotely.
[0004] Data is sent to the central database via Internet, GPRS or GSM.
[0005] The grey water regeneration system of the present invention ensures that the quality of the obtained purified water is the adequate thanks to the fact that all devices are controlled by a PLC, so that in the case that any malfunction is detected in the system, the PLC acts accordingly solving this problem.
[0006] The grey water regeneration system of the present invention ensures that the supply of the purified water has a high enough quality to be reused, because if the PLC detects any malfunction during the measurement, it acts in a way to solve the detected problem.
[0007] The grey water regeneration system fully controlled by a PLC object of the invention mainly comprises four tanks.
[0008] A primary collection tank that receives the grey water to then supply it to the purification system and which comprises a filter at the inflow; a secondary tank, wherein a biological purification takes place by means of activated sludge, which comprises a suction pump and a membrane, and a tertiary tank where a chlorine disinfection takes place, wherein each of the tanks is connected to the general collector.
BACKGROUND OF THE INVENTION
[0009] The world's water resources are limited and, geographically, their availability is not evenly distributed. Only 1% of the total existing water is available fresh water and therefore it can be used for human consumption.
[0010] Water reuse presents itself as an appropriate alternative.
[0011] There are preceding grey water reuse systems, such as the patent with publication number ES2281262 which discloses a system for the desalination and recycling of oily water and liquid waste. This system uses no filters, membranes or chemicals to produce pure water, and energy. This system consists of a closed circuit machine, through which the waste water is introduced, subjecting it to an evaporation process, recovering the concentrated material (not evaporated), and producing clean water and energy.
[0012] There are also pre-existing waste water treatment systems, as described in the patent WO2008015350 which discloses a method and a device for purifying both urban and industrial waste water. The method consists of a process for biologically treating urban or industrial waste water, during which the organic matter contained in the water is decomposed by microorganisms, generating activated sludge. It also consists of a decanting process, in which all or part of the sludge at the end of this stage is exposed to hydrogen peroxide.
[0013] The most restrictive factor for the reuse of treated water is the quality of the regenerated water.
[0014] Legislation on water reuse is very restrictive in terms of setting the minimum requirements that treated water must meet to be reused.
[0015] Thus, the invention here presented beats the previous inventions in that the grey water regeneration system object of the invention is a purification system that ensures that the quality of the water delivered for the different uses of this treated water is optimal.
[0016] The grey water regeneration system of the present invention ensures the quality of the resulting purified water by means of an integrated control system because it combines the existing purification systems with the best technology available giving full guarantee to the quality of treated water.
[0017] Thus, the system is controlled by a PLC which monitors the operation of the system using sensors that detect the presence of suspended solids, turbidity, pH and using filling level sensors for each different tank . . . etc and it also adjusts the various devices, including pumps, valves, dispensing pumps or any other system device.
[0018] The way to ensure that the quality of the purified water to be served to different uses demanding water for reuse is adequate is achieved because all the devices are controlled by the PLC, so that in the case that any problem is detected in the system, the water can evacuate to the general collector.
[0019] Furthermore, the present invention has other advantages: the generated organic load is minimal and easily degradable and no sludge or residue requiring authorized measures is generated and besides it requires less operating time and simple installations.
SUMMARY OF THE INVENTION
[0020] The grey water regeneration system object of this invention is a grey water purification system that ensures a resulting high quality purified water for reuse.
[0021] For this, the system includes sensors that fully monitor the operation of the system by means of a PLC that is designed to monitor in real time, the operation of the system at all sequential processes occurring in each of the tanks of the purification system object of this invention.
[0022] The grey water regeneration system object of the present invention ensures that the quality of the purified water delivered for the different uses of this treated water is the adequate thanks to the fact that all devices are controlled by a PLC, so that in the case that a malfunction is detected in the system, the PLC acts accordingly solving this problem.
[0023] The PLC controls the operation of the system through sensors that include pH sensors, suspended solid sensors, turbidity sensors, residual chlorine sensors, tank filling level sensors, level sensors for the dispensing devices and pressure sensors.
[0024] The PLC also monitors all the devices in the system. These devices are controlled by the PLC are mainly valves, solenoid valves and pumps within the system.
[0025] These data collected by the PLC is reported to a central database, so that the monitoring can be performed remotely.
[0026] Data is sent to the central database via Internet, GPRS or GSM, and can thus the system can be controlled remotely.
[0027] The grey water regenerating system of the present invention ensures that the supply of purified water has a high enough quality to be reused, because if the PLC detects any malfunction during the measurement, it will adapt to solve the detected problem.
[0028] So, it is because of the PLC that the system is fully controlled in real time throughout the whole process, allowing a remote management of the installation by means of an alarm system which connects to the central database.
[0029] This greatly facilitates the maintenance of the system, and it also ensures that the quality of the water is adequate for reuse.
[0030] The term “grey water” of the present specification is used to refer to the water from the drains of tubs, showers, washbasins, dishwashers and washing machines.
[0031] The water regeneration system of the present invention is intended mainly for houses, apartment buildings and housing developments or condominium housing units.
[0032] Thus, the system can be used as a solution for water reuse in houses and apartment buildings where the grey water regeneration system of the present invention will be installed preferably in basements, may yet be installed in any other place required by the builder.
[0033] Specially, when the system is used as a solution for water reuse in housing developments and condominiums, the system can be installed underground.
[0034] The grey water regeneration system fully controlled by a PLC comprises the following elements:
[0035] A grey water primary collection tank that receives water to then gradually supply it to the purification system.
[0036] In an embodiment of the invention, before the primary tank inlet, there is a pH indicator device. In the case that the grey water has a pH that falls out the range 4-9.5, the water is disposed to a general collector and the purification process will not take place.
[0037] So, the primary device consists of, in an embodiment of the invention, an overflow drain which is directly connected to the general collector and will eliminate all substances with lower density than water, i.e. substances with density inferior to 1 g/cm 3 , and will also evacuate waste water which is not within the range of pH 4-9.5.
[0038] This monitoring prevents the water containing abrasive and disinfectant products, bleach or any other cleaning product, pharmaceuticals with biocidal properties or any other chemical product that can endanger the smooth functioning of the system, from being disposed to the general collector, as if it continued with the purification treatment, the water obtained for reuse would not meet the established legal requirements.
[0039] This is so because these products destruct the sludge that enables the biological treatment taking place in the secondary tank, which will be explained later in this specification.
[0040] This overflow drain also disposes all the water that exceeds the storage capacity of the tank to the general collector.
[0041] The primary tank comprises at least one filter, preferably a mesh filter, at the inflow and optionally another filter at the outflow and also optionally, a blender that homogenizes the mixture.
[0042] This primary tank has also a level sensor that informs the PLC of the filling level.
[0043] If the PLC detects a malfunction before the water goes into the regeneration system, the water can be discharged through a solenoid valve to the general collector.
[0044] This primary tank includes, in a first embodiment of the invention, an outlet pipe that has a manual valve followed by a solenoid valve which is connected to the collector, so that, if the PLC detects any malfunction, the water is discharged into the general collector.
[0045] A second pipe branches off from the primary tank outlet pipe, which communicates with a pump and, if conditions are optimal, the water is drawn by the pump into a secondary tank.
[0046] The primary tank pump provides water to the secondary tank. Before the water goes into the secondary tank, nitrogen and phosphorus are added to make up for the lack of nutrients in the water that the biological reaction may cause.
[0047] Nitrogen and phosphorus are added by means of the difference in pressure of the communicating ducts, or by using solenoid valves, metering pumps or dispensers.
[0048] In another second embodiment of the invention, the primary tank is only connected to the general collector through the overflow drain that directs excess water and any substance that has lower density than water.
[0049] The primary tank, in this embodiment of the invention, is just above a secondary tank and the water is delivered from the first to the second tank by gravity force, with the help of a floating valve within the secondary tank.
[0050] Biological and refining treatment takes place in this secondary tank. For this purpose, the secondary tank comprises at least one aerator and one suction pump that generate air currents so the water is infused with oxygen and is impelled through at least one membrane. This one can be a microfiltration, nanofiltration or ultrafiltration membrane.
[0051] The secondary tank outlet pipe comprises a manual valve followed by a solenoid valve which is controlled by the PLC. This outlet is connected to the general collector so that the water can be discharged to waste.
[0052] In the secondary tank, the water is passed through at least one membrane by means of the suction pump and it is pushed up into an outlet pipe that connects the secondary and the tertiary tank.
[0053] The tertiary tank comprises a chlorine dispenser as disinfection system. Chlorine can be dispensed by means of difference in section of the communicating ducts, or through solenoid valves, metering pumps or dispensers placed before the inlet of the tank. Chlorine can also be added in the tertiary tank itself.
[0054] The tertiary tank outlet pipe comprises a manual valve followed by a solenoid valve controlled by the PLC. This outlet is connected to a drain pipe that discharges water to the general collector.
[0055] The tertiary tank comprises a second outlet that connects the different uses of the treated water.
[0056] In this second outlet of the tertiary tank there is a solenoid valve diverting water whose quality will be measured by a device comprising at least pH sensors, suspended solid sensors, turbidity sensors and residual chlorine sensors.
[0057] The upright pipe that delivers water for the different uses of this treated water includes a pressure sensor that detects the need for water in the upright pipe and if the quality of the purified water is the adequate and there is water in the tertiary tank, water is drawn from the tertiary tank by means of a pump.
[0058] In the event that no water is available or the quality of the water is not optimal, or in the case that the PLC detects a malfunction, the water is supplied from the ordinary potable water network through a valve that selects the water flow.
[0059] Optionally, the grey water regeneration system may incorporate a fourth tank for rainwater, which comprises a filter, preferably a sand filter that connects directly to the tertiary tank and a further chlorine dispenser.
[0060] In an embodiment of the invention, the treated water that will be reused is tinted so that it can be distinguished from drinking water.
[0061] For this purpose, the system includes a dye dispenser.
[0062] The system comprises level sensors in each of the tanks.
[0063] To sum up, the present invention describes a grey water regeneration system which is fully controlled by a PLC, comprising a grey water primary collection tank, a secondary tank including at least an aerator, a membrane and a suction pump, and a tertiary tank in which a chlorination takes place, wherein the primary, the secondary and tertiary tanks are all connected to the general collector.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] The present specification is additionally described by a set of illustrative drawings including, but not limited to the preferred embodiment of the invention.
[0065] FIG. 1 is a first embodiment of the grey water regeneration system of the present invention.
[0066] FIG. 2 is a second embodiment of the grey water regeneration system of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0067] FIG. 1 is a first preferred embodiment of the invention.
[0068] In this preferred embodiment, the grey water regeneration system comprises three tanks:
[0069] A grey water primary collection tank ( 1 ) that receives water to then gradually supply it to the purification system.
[0070] In this preferred embodiment, the grey water regeneration system has a pH sensor ( 2 ), before the inlet of the primary tank ( 1 ). In the case that the grey water has a pH that falls within the range 4-9.5, the water is diverted to a general collector ( 5 ) and the purification process will not take place.
[0071] In this preferred embodiment, the primary tank ( 1 ) has a mesh filter ( 3 ) at the inlet and another mesh filter ( 4 ) at the outlet and a blender device, which in this embodiment is a blade, that homogenizes the mixture ( 6 ).
[0072] So, the primary device consists of, in this embodiment of the invention, an overflow drain ( 2 ′) which is directly connected to the general collector ( 5 ) and will eliminate all substances with lower density than water, i.e. substances with density inferior to 1 g/cm 3 , and will also evacuate waste water which is not within the range of pH 4-9.5.
[0073] Additionally, the overflow drain ( 2 ′) can evacuate the excess water from the primary tank ( 1 ).
[0074] This primary tank ( 1 ) includes, in a first embodiment of the invention, an outlet pipe ( 7 ) that consists of manual valve ( 8 ′) followed by a solenoid valve ( 8 ′) which is connected to the collector ( 5 ), so that if the PLC detects a malfunction, the water is discharged into the general collector.
[0075] From this outlet pipe ( 7 ) of the primary tank ( 1 ) a second pipe ( 9 ) comes out, which communicates with a pump ( 10 ) that impels water into a secondary tank ( 11 ).
[0076] The primary tank pump ( 1 ) provides water to the secondary tank ( 11 ). Before the water goes into the secondary tank ( 11 ), nitrogen and phosphorus are added to make up for the lack of nutrients in the water that the biological reaction may cause. In this embodiment, nitrogen and phosphorous are added using dispensers which are coupled to the second outlet pipe ( 9 ) of the primary tank ( 1 ).
[0077] So, before the inlet of the secondary tank, there is a nitrogen dispenser ( 12 ) and a phosphorus dispenser ( 13 ).
[0078] In the secondary tank ( 11 ) a biological and refining treatment takes place. To this purpose, the secondary tank ( 11 ) of this preferred embodiment comprises at least one aerator ( 14 ) and so that the water is infused with oxygen and is impelled, with the help of a suction pump ( 31 ), through a membrane ( 15 ), which in this embodiment is an ultrafiltration membrane.
[0079] The water passes through the membrane ( 15 ) with the help of a suction pump ( 31 ).
[0080] The outlet pipe ( 16 ) of the secondary tank ( 11 ) has a manual valve ( 17 ) followed by a solenoid valve which is controlled by the PLC. This outlet is connected to the collector ( 5 ) so the water can be discharged to the general collector.
[0081] In the secondary tank, water is passed through at least one membrane ( 15 ) and is directed with the help of a suction pump ( 31 ) to an outlet pipe ( 18 ) which connects the secondary tank ( 11 ) with the tertiary tank ( 19 ).
[0082] Before the inlet of the tertiary tank ( 19 ), there is a chlorine dispenser ( 20 ) as disinfection system.
[0083] The outlet pipe ( 21 ) of the tertiary tank has a manual valve ( 22 ) followed by a solenoid valve which is controlled by the PLC. This outlet pipe discharges water to the general collector ( 5 ).
[0084] The tertiary tank ( 19 ) has a second outlet pipe ( 23 ) that connects the different uses of the treated water.
[0085] In this second outlet ( 23 ) of the tertiary tank ( 19 ) there is a manual valve ( 24 ) followed by a solenoid valve which diverts water so that the quality of the water can be measured by a device ( 25 ), which in this embodiment comprises pH sensors, suspended solid sensors, turbidity sensors and residual chlorine sensors.
[0086] The second outlet ( 23 ) of the tertiary tank ( 19 ) comprises a pressure sensor ( 26 ) that detects the need for water in the upright pipe ( 27 ) that delivers water for the different uses of the treated water and if the quality of the purified water is correct and there is water in the tertiary tank ( 19 ) the water is drawn from the tertiary tank ( 19 ) by a pump ( 28 ).
[0087] In the event that no water is available or that the quality of the water is not optimal, the water is supplied from the ordinary drinking water network.
[0088] In this preferred embodiment, the invention includes a membrane self-cleaning system connecting the tertiary tank ( 19 ) to the secondary tank ( 11 ) by means of a pump ( 29 ). This backwash lasts approximately 15 minutes.
[0089] After 30 minutes of water flowing through the membranes ( 12 ), the suction is stopped and the flow of water is reversed so that the force of the water tosses the particles blocking the membranes. For maximum effectiveness, chlorine is added to the water by a chlorine dispenser.
[0090] FIG. 2 is a second preferred embodiment of the invention.
[0091] In this preferred embodiment, the grey water regeneration system comprises three tanks.
[0092] This preferred embodiment is characterized by a primary tank ( 1 ) placed above a secondary tank ( 11 ).
[0093] A grey water primary collection tank ( 1 ) that receives water to then gradually supply it to the purification system.
[0094] In this preferred embodiment, the primary tank ( 1 ) comprises a blender that homogenizes the mixture ( 6 ).
[0095] The primary device has, in this embodiment of the invention, an overflow drain ( 2 ′) which is directly connected to the general collector ( 5 ).
[0096] This primary tank ( 1 ) has an outlet pipe ( 7 ) that connects to the secondary tank ( 11 ). This secondary tank ( 11 ) is gravity fed. The opening/close is allowed by means of a float or a solenoid valve ( 32 ) within the secondary tank ( 11 ).
[0097] Before the water goes into the secondary tank ( 11 ), nitrogen and phosphorus are added to make up for the lack of nutrients in the water that the biological reaction may cause.
[0098] In this embodiment, the nitrogen and phosphorous are added using dispensers which are located above the secondary tank ( 11 ).
[0099] So, in the upper part of the secondary tank ( 11 ), there is a nitrogen dispenser ( 12 ) and a phosphorus dispenser ( 13 ).
[0100] In the secondary tank ( 11 ) a biological and refining treatment takes place. To this purpose, the secondary tank ( 11 ) of this preferred embodiment comprises at least one aerator ( 14 ) that blows air that generate air currents that cause the water to oxygenate and pass through a membrane ( 15 ), which in this embodiment is an ultrafiltration membrane.
[0101] The outlet pipe ( 16 ) of the secondary tank ( 11 ) has a manual valve ( 17 ) followed by a solenoid valve which is controlled by the PLC. This outlet ( 16 ) is connected to the collector ( 5 ) so the water can be discharged to the general collector.
[0102] In the secondary tank ( 11 ), water is passed through at least one membrane ( 15 ) and is impelled with the help of a suction pump ( 31 ) to an outlet pipe ( 18 ) which connects the secondary tank ( 11 ) with the tertiary tank ( 19 ).
[0103] Before the inlet of the tertiary tank ( 19 ), there is a chlorine dispenser ( 20 ) as disinfection system.
[0104] The outlet pipe ( 21 ) of the tertiary tank has a manual valve ( 22 ) followed by a solenoid valve which is controlled by the PLC. This output is connected to a pipe that delivers water to the collector ( 5 ).
[0105] The tertiary tank ( 19 ) has a second outlet ( 23 ) that provides water for the different uses of the treated water.
[0106] In this second outlet ( 23 ) of the tertiary tank ( 16 ) there is a solenoid valve ( 24 ) which diverts water so that the quality of the water can be measured by a device ( 25 ), which in this embodiment comprises pH sensors, suspended solid sensors, turbidity sensors and residual chlorine sensors. The upright pipe ( 27 ) comprises a pressure sensor ( 26 ) that detects the need for water in the upright pipe ( 27 ) that delivers water for the different uses of the treated water and if the quality of the purified water is correct and there is water in the tertiary tank ( 19 ) the water is drawn from the tertiary tank ( 19 ) by a pump ( 28 ).
[0107] In the event that no water is available or that the quality of the water is not optimal, the water is supplied from the ordinary drinking water network.
[0108] Variations in the materials, shape, size and arrangements of the components, which are described in non-limiting basis, do not alter the essence of this invention, which is sufficient for an expert to carry out the procedure.
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The object of this invention is a grey water regeneration system for its subsequent reuse which guarantees the quality of the purified water, disposing of sensors which fully control the process by means of an automaton programmed so that if it detects any problem in the system, the water can be evacuated to the general collector ( 5 ), and comprises a primary receptor tank ( 1 ) of the grey water that gathers to then supply it to the purification system, a secondary tank ( 11 ) wherein a biological purification takes place by means of activated sludge which comprise an aerator ( 14 ), a membrane ( 15 ) and a suction pump ( 31 ), and a tertiary tank ( 19 ) wherein a disinfection takes place by means of chloride additivation, wherein all of the tanks are connected to the general collector ( 5 ).
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This application is a division of application Ser. No. 08/710,196, filed Sep. 13,1996 now U.S. Pat. No. 5,709,378.
The present invention generally relates to springs and spring devices for providing bias, sealing, electromagnetic shielding and conductivity, and is more particularly directed to joining of coil springs while at the same time maintaining spring characteristics during deflection, i.e., either radial or axial, compression, of the coils, and extension caused by loading of the spring along a central axis throughout.
When spring ends are joined to form a closed spring, such as, for example, an annulus, a further distinguishing feature of such annular springs is their suitability for either radial loading, i.e., along a radius of the annular spring, or axial loading, i.e., along an axis of the spring annulus.
The joining of the spring ends is a problem that has been addressed throughout the years but with generally unsatisfactory results. This is primarily due to the fact that the joined ends of the spring do not have the same load deflection characteristics as intermediate portions of the spring, thus resulting in a nonuniform biasing, or loading, of parts which can result in inefficient sealing blockage of electromagnetic waves and nonuniform conductivity.
As specifically pointed out in U.S. Pat. No. 3,190,633, springs are usually formed of tempered steel and therefore many times cannot be joined at the extreme end by soldering since such joint would be too weak. Nor can they be joined by brazing or welding, since the heat necessary for such joining often destroys the temper of the steel.
In an attempt to overcome the problems inherent with welding or soldering, U.S. Pat. No. 3,190,633 utilizes a coupling in the form of a tube for the joining of the spring ends. Unfortunately, this introduces a nonlinearity in the spring size; and further, due to the bulkiness of the coupling, uniform load characteristics cannot be obtained throughout the spring structure which results in the limitations as hereinabove discussed.
Further elaboration on the disadvantages of joining the ends of a spring by adhesive or a solder includes the time-consuming operation for effecting the union, and the spring is made less efficient, particularly if a number of the spring coils are loaded with solder. This latter configuration also increases in a nonuniform manner the weight of the spring and contributes significantly to a nonlinearity of the spring characteristics in the region of the joined ends.
Other known methods of constructing annular devices have been taught in the art over a great number of years. For example, one known method is to provide on one end of the coiled spring, coils of smaller diameter, while another end includes a diameter consistent with intermediate coils of the spring. Coupling is accomplished by forcing the reduced diameter end into the other end, such-as set forth in U.S. Pat. Nos. 266,529; 3,011,775; and 3,186,701. However, in all of these springs, the outer coils are supported by inner coils which, in the area of the joint, disrupt the load-deflection characteristics of the outer coils.
A further teaching of this type of spring may be found in U.S. Pat. No. 3,276,761, in which the end having reduced diameter also has protruding spring forms for engaging spring convolutions of another end of a spring. Again, the overall configuration of the joint to not enable freedom of movement of the outer coils during compression.
Alternative teachings of spring joining provide for a spring coil of constant diameter with the ends connected by forcing them on to a connecting member, or plug, which is received and positioned within two ends. In this regard, U.S. Pat. No. 735,731 utilizes a screw, or headless plug, with screw threads of substantially the same pitch as the coils of the spring. While this results in an endless helical spring, uniformity of resilience along the helical spring cannot be expected due to the size of the screw utilized for connecting ends of the spring.
U.S. Pat. No. 1,867,723 discloses a coupling member in the form of a cap. U.S. Pat. No. 2,001,835 utilizes a connector formed with a plurality of convolutions of relatively larger diameter for engagement with a constant diameter coil spring.
Other teachings of the connector member include U.S. Pat. No. 2,778,697, which shows a connector strip provided with a set of semicircular recesses for accepting coils of both ends of a coiled spring. A variation of this design is shown in U.S. Pat. No. 3,157,056, in which the strip taught in U.S. Pat No. 2,778,697 is replaced by a cylindrical member having recesses for accepting coil springs.
All of this, of course, obviously interfere with the operation of the spring in the area of the coupling member and therefore do not achieve consistent spring characteristics which are necessary for both efficient biasing and sealing.
Other connecting members are shown in U.S. Pat. No. 2,721,091, showing a rubber embedded helix; U.S. Pat. No. 2,779,647, which shows a keeper link arrangement; and U.S. Pat. Nos. 3,359,617 and 4,718,868 which show a spring-connecting member.
As set forth in U.S. Pat. No. 2,991,061, other known methods for joining helical coils include a hook or loop formed on each end of the coil which are connected to form the coil into an annulus and methods which include springs having one or more convolutions at each end which are spaced apart from one another, so they may be connected by being intertwined together to connect the two ends to form an annular spring device.
However, all of these methods have serious disadvantages, as pointed out in U.S. Pat. No. 2,991,064, and in none of them is produced an annular spring having ends which are so firmly connected that the spring will withstand severe vibration and shock without malformation or separation of the ends or excessive extension or unwinding.
Further, the springs have uniform load deflection characteristics due to the interrupted nature of the spring coupling device utilized.
The present invention overcomes the difficulties of the prior art and provides an array of coil-joining techniques which are suitable for either axial-type springs, radial-type springs in which the spring utilized can have canted external coils that can be round, elliptical, square or rectangular, or a combination.
SUMMARY OF THE INVENTION
Spring apparatus, in accordance with the present invention, generally includes a coil spring having two ends and a plurality of intermediate coils canted along the centerline of the coil spring with each coil having a leading portion disposed at a front angle to a normal line to the centerline and a trailing portion disposed at a back angle to the normal line. The intermediate coils may be round, elliptical, square, rectangular or a combination of two or more of the recited shapes.
Importantly, end coils congruent with the plurality of intermediate coils are disposed at the two ends and include back angle means, defining a trailing portion of at least one end coil, for locking the end coils together. In this instance, the end coil trailing portion of the end coil has a back angle different from the intermediate coil trailing portion back angle. When joined, the resulting continuous coil may be configured for axial or radial loading.
More particularly, the apparatus in accordance with the present invention may include an end coil trailing portion having a decreasing back angle along the length of the end coil. In addition, one of the end coils may be tapered, or both of the end coils may be tapered.
In one embodiment of the present invention, the end coils are tapered asymmetric to the centerline of the coil spring. In addition, where the intermediate coils are elliptical, they may be tapered along a major and/or along a minor axis of the coils. In one embodiment of the present invention, the end coils are both tapered asymmetric to the centerline of the coil spring, and in the embodiment where the coil springs are elliptical, the end coils may be elliptical with at least one of the coils being offset along a major axis thereof.
The spring ends may be held together by a snap action, that can consist of threading, straight push, or a combination twist and push can cause the ends to be locked together or have interference between coils to cause the coils to engage each other by having the end coils round or elliptical. In this instance, the means for causing the end coils to snap together is an elliptical shape thereof, which causes a portion of the elliptical shaped end coil to extend exterior to a circumference of another end coil.
In this last embodiment, the intermediate coils and the end coils may be elliptical. Further, the end coils have a coil height, measured along a minor axis thereof, which is substantially smaller than an intermediate coil height, measured along a minor axis thereof.
The hereinabove recited embodiments, as well as the hereinafter recited embodiments of the present invention, enable the coupling of the ends of a spring to form a continuous spring in which the coupling of the end coils do not inhibit or substantially affect the load-deflection characteristics of the continuous spring in the area of the joint end coils. This occurs because the joining configuration, namely, the coupling end portions, do not interfere with the compression or expansion of the intermediate coils of the spring because of their size, position or both with regard to the intermediate coils.
In another embodiment of the present invention, the end coils may have a reduced diameter, i.e., "stepped-down" from the size of the intermediate coils.
In various embodiments of the present invention, the end coils may have an exterior male, round, elliptical, or offset, and an interior female, round, elliptical, or offset, or alternatively the end stepped-down coils may have both an exterior male configuration and an exterior female configuration. In these embodiments, as hereinafter described in greater detail, the end coils may be threaded, snapped on, pushed on, or pushed on in a manner to provide locking action.
Further, a coil in the nature of a hook may be provided for further securing a locking of the end coils together with the hook coil being interior to the intermediate coils.
In addition, all of the embodiments of the present invention may be further combined with an elastomer having either a solid center or a hollow center in order to provide sealing, shielding, added force, or enhancing the conductivity by enabling portions of the coil to be bare to enable enhanced conductivity.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the present invention will be better understood by the following description when considered in conjunction with the accompanying drawings in which:
FIG. 1 is a cutaway side view of one embodiment of the present invention, generally showing coupling of two end coils to form a continuous coil spring;
FIG. 2 is a top view of an end coil corresponding to FIG. 1, prior to assembly;
FIG. 3 is a top view of another end coil according to FIG. 1, prior to assembly;
FIG. 4 is a side view of the end coil shown in FIG. 2;
FIG. 5 is a side view of the end coil shown in FIG. 3;
FIG. 6 is a view of the coil spring shown in FIG. 1, taken along the line 6--6;
FIG. 7 is a view of the coil spring shown in FIG. 1, taken along the line 7--7;
FIG. 8 is a view of the coil spring in FIG. 1, taken along the line 8--8;
FIG. 9 is a cutaway side view of an assembled coil spring in accordance with another embodiment of the present invention;
FIG. 10 is a top view of one end coil of the assembly shown in FIG. 9;
FIG. 11 is a top view of another end coil of the assembly shown in FIG. 9, specifically showing portions of elliptical coils thereof for causing the locking action;
FIG. 12 is a side view of the end coil shown in FIG. 10;
FIG. 13 is a side view of the end coil shown in FIG. 11;
FIG. 14 is a view of the assembly shown in FIG. 9, taken along the line 14--14;
FIG. 15 is a view of the assembly shown in FIG. 9, taken along the line 15--15;
FIG. 16 is a view of the assembly shown in FIG. 9, taken along the line 16--16;
FIG. 17 is a cutaway side view of a spring assembly in accordance with yet another embodiment of the present invention;
FIG. 18 is a top view of an end coil of the assembly shown in FIG. 17;
FIG. 19 is a top view of another end coil of the assembly shown in FIG. 17, showing protruding elliptical coils which provide for back angle locking;
FIG. 20 is a side view of the end coil shown in FIG. 18;
FIG. 21 is a side view of the end coil shown in FIG. 19;
FIG. 22 is a view of the assembly shown in FIG. 17, taken along the line 22--22;
FIG. 23 is a view of the assembly shown in FIG. 13, taken along the line 23--23;
FIG. 24 is a view of the assembly shown in FIG. 17, taken along the line 24--24;
FIG. 25 is a cutaway side view of an assembled coil spring in accordance with yet another embodiment of the present invention;
FIG. 26 is a top view of an end coil of the assembly shown in FIG. 25;
FIG. 27 is a top view of another end coil shown in FIG. 25;
FIG. 28 is a side view of the end coil shown in FIG. 26;
FIG. 29 is a side view of the end coil shown in FIG. 27;
FIG. 30 is a view of the spring assembly shown in FIG. 25, taken along the line 30--30;
FIG. 31 is a view of the assembly shown in FIG. 25, taken along the line 31--31;
FIG. 32 is a view of the assembly shown in FIG. 25, taken along the line 32--32;
FIG. 33 is a view of the assembly shown in shown in FIG. 25, taken along the line 33--33;
FIG. 34 is a cutaway side view of an assembled coil spring configuration, in accordance with still another embodiment of the present invention;
FIG. 35 is a top view of an end coil of the assembly shown in FIG. 34;
FIG. 36 is a top view of another end coil of the assembly shown in FIG. 34;
FIG. 37 is a side view of the end coil shown in FIG. 35;
FIG. 38 is a side view of the end coil shown in FIG. 36;
FIG. 39 is a view of the assembly shown in FIG. 34, taken along the line 39--39;
FIG. 40 is a view of the assembly shown in FIG. 34, taken along the line 40--40;
FIG. 41 is a view of the assembly shown in FIG. 34, taken along the line 41--41;
FIG. 42 is a top view of an assembled spring apparatus, in accordance with another embodiment of the present invention;
FIG. 43 is a cutaway side view of the assembly shown in FIG. 42;
FIG. 44 is a top view of one end coil of the assembly shown in FIG. 42;
FIG. 45 is a top view of another end coil of the assembly shown in FIG. 42;
FIG. 46 is a side view of the end coil shown in FIG. 44;
FIG. 47 is a side view of the end coil shown in FIG. 45;
FIG. 48 is a view of the assembly shown in FIG. 43 taken along the line 48--48;
FIG. 49 is a view of the assembly shown in FIG. 43, taken along the line 49--49;
FIG. 50 is a view of the assembly shown in FIG. 43, taken along the line 50--50;
FIG. 51 is a top view of another spring assembly, in accordance with still another embodiment of the present invention;
FIG. 52 is a cutaway side view of the assembly shown in FIG. 51;
FIG. 53 is a top view of one end coil of the assembly shown in FIG. 52;
FIG. 54 is a top view of another coil of the assembly shown in FIG. 52;
FIG. 55 is a side view of the end coil shown in FIG. 53;
FIG. 56 is a side view of the end coil shown in FIG. 54;
FIG. 57 is a view of the assembly shown in FIG. 52, taken along the line 57--57;
FIG. 58 is a view of the assembly shown in FIG. 52, taken along the line 58--58;
FIG. 59 is a view of the assembly shown in FIG. 52, taken along the line 59--59;
FIG. 60 is a cutaway side view of a spring assembly, in accordance with the present invention utilizing a circular canted spring with an elliptical snap-on coupling;
FIG. 61 is a view of the assembly shown in FIG. 60, taken along the line 61--61;
FIG. 62 is a cutaway side view of a spring assembly, in accordance with the present invention, wherein the intermediate coils are square, and the end coils are elliptical;
FIG. 63 is a view of the spring assembly shown in FIG. 62, taken along the line 63--63;
FIG. 64 is a cutaway side view of a spring assembly, utilizing rectangular intermediate coils and circular end coils;
FIG. 65 is a view of the spring assembly shown in FIG. 64, taken along the line 65--65;
FIG. 66 is a cutaway side view of a spring assembly, utilizing circular intermediate coils with circular canted end coils for snap-on engagement;
FIG. 67 is a view of the spring assembly shown in FIG. 66, taken along the line 67--67;
FIG. 68 is a cutaway side view of a spring assembly, utilizing elliptical canted intermediate coils and elliptical end coils;
FIG. 69 is a view of the spring assembly shown in FIG. 68, taken along the line 69--69;
FIG. 70 is a cutaway side view of an assembly of an embodiment of the present invention similar to that shown in FIG. 68;
FIG. 71 is a view of the spring assembly shown in FIG. 70, taken along the line 71--71;
FIG. 72 is a top view of another embodiment of the present invention utilizing male and female end coils;
FIG. 73 is a side view of an end coil of the spring assembly shown in FIG. 72 in which the end coils are abutting;
FIG. 74 is a side view of another end coil of the spring assembly shown in FIG. 72 in which the female end coils is disposed within the intermediate coils;
FIG. 75 is a view of the end coil shown in FIG. 73, taken along the line 75--75;
FIG. 76 is a view of the end coil shown in FIG. 74, taken along the line 76--76;
FIG. 77 is a top view of a spring assembly similar to that shown in FIG. 72 in which the end coils are spaced apart;
FIG. 78 is a side view of an end coil of the spring assembly shown in FIG. 77;
FIG. 79 is a side view of another end coil of the spring assembly shown in FIG. 77;
FIG. 80 is a top view of another spring assembly similar to that shown in FIG. 77 in which one end coil is tapered;
FIG. 81 is a side view of an end coil of the spring assembly shown in FIG. 80;
FIG. 82 is a side view of another end coil of the spring assembly shown in FIG. 80;
FIG. 83 is a top view of a spring assembly in which the end coils include abutting tapered coils;
FIG. 84 is a side view of an end coil of the spring assembly shown in FIG. 83;
FIG. 85 is a side view of another end coil of the spring assembly shown in FIG. 83;
FIG. 86 is a spring assembly similar to that shown in FIG. 83 with separate tapered end coils;
FIG. 87 is a side view of an end coil of the spring assembly shown in FIG. 86;
FIG. 88 is a side view of another end coil of the spring assembly shown in FIG. 86;
FIGS. 89a and 89b are side views of a spring assembly similar to FIG. 77 in which the intermediate coils are rectangular and the one end coil is male, having exterior spaced apart coils;
FIGS. 90a and 90b show a female end coil disposed within intermediate coils for coupling with the end coils shown in FIGS. 89a and 89b;
FIG. 91 is a side view of a spring assembly formed by coupling of the end coils shown in FIGS. 89a and 90b;
FIG. 92 is a top view of an alternative embodiment of the spring assembly, in accordance with the present invention, utilizing two end coils and an insert coil;
FIG. 93 is a side view of the spring assembly shown in FIG. 92;
FIG. 94 is a partially cutaway side view of the coil assembly shown in FIG. 92 when fully assembled;
FIG. 95 is a view of the spring assembly shown in FIG. 93 taken along the line 95--95;
FIG. 96 is a view of the spring assembly shown in FIG. 93 taken along the line 96--96;
FIG. 97 is a top view of an alternative embodiment of the present invention, similar to FIG. 77, in which both the male and female end coils are exterior to the intermediate coils;
FIG. 98 is a side view of an end coil of the spring assembly shown in FIG. 97;
FIG. 99 is a side view of another end coil of the spring assembly shown in FIG. 98 in which the female end coil is exterior to the intermediate coils;
FIG. 100 is a view of the end coils shown in FIG. 98 taken along the line 100--100;
FIG. 101 is a view of the end coil shown in FIG. 99 taken along the line 101--101;
FIG. 102 is a cutaway side view of the spring assembly shown in FIG. 97 at maximum deflection, illustrating independence of the deflection of the intermediate coils from the coupling end coils;
FIG. 103 is a top view of still another embodiment of the present invention, utilizing triangular end coils;
FIG. 104 is a side view of one end coil of the spring assembly shown in FIG. 103;
FIG. 105 is a side view of another end coil of the spring assembly shown in FIG. 103;
FIG. 106 is a view of the end coil shown in FIG. 104 taken along the line 106--106;
FIG. 107 is a view of the end coil shown in FIG. 105 taken along the line 107--107;
FIG. 108 is a cutaway side view of the spring assembly shown in FIG. 103 at maximum deflection;
FIG. 109 is a top view of yet another embodiment of the present invention similar to the assembly shown in FIG. 103;
FIG. 110 is a side view of an end coil of the spring assembly shown in FIG. 109;
FIG. 111 is a side view of another end coil of the spring assembly shown in FIG. 109;
FIG. 112 is a view of the end coil shown in FIG. 110 taken along the line 112--112;
FIG. 113 is a cutaway side view of the spring assembly 109 at maximum deflection under a load (not shown);
FIG. 114 is a view of the end coil shown in FIG. 111 taken along the line 114--114;
FIG. 115 is a view of the end coil shown in FIG. 111 taken along the line 115--115;
FIG. 116 is a top view of a spring assembly, in accordance with the present invention, utilizing an end locking system with a male hook stem;
FIG. 117 is a side view of a male end coil of the spring assembly shown in FIG. 116 showing a male hook stem with a bent latch and abutting coils;
FIG. 118 is a side view of a female end coil of the spring assembly shown in FIG. 116 having round centered coil abutting coils;
FIG. 119 is a view of the end coil shown in FIG. 117 taken along the line 119--119;
FIG. 120 is a view of the end coil shown in FIG. 118 taken along the line 120--120;
FIG. 121 is a cutaway side view of the spring assembly shown in FIG. 116 at maximum deflection and illustrating the coupled end coils not being in interference with the deflection of the intermediate coils upon loading;
FIG. 122 is a side view of a spring assembly, in accordance with the present invention, further including an elastomer surrounding the intermediate and end coils;
FIG. 123 is a view of the spring assembly shown in FIG. 122 taken along the line A--A in one embodiment in which the elastomer has a solid center;
FIG. 124 is a view of the spring assembly shown in FIG. 122 taken along the line A--A in which the elastomer has a hollow center;
FIG. 125 is a view of the spring assembly shown in FIG. 122 taken along the line B--B in which the elastomer has a solid center;
FIG. 126 is a view of the spring assembly shown in FIG. 122 taken along the line B--B in which the elastomer has a hollow center;
FIG. 127 is a view of the spring assembly shown in FIG. 122 taken along the line C--C in which the elastomer has a solid center;
FIG. 128 is a view of the spring assembly shown in FIG. 122 taken along the line C--C in which the elastomer has a hollow center;
FIG. 129 is a view of the spring assembly shown in FIG. 122 taken along the line D--D in which the elastomer has a solid center;
FIG. 130 is a view of the spring assembly shown in FIG. 122 taken along the line D--D in which the elastomer has a hollow center;
FIG. 131 is a side view of uncanted, circular intermediate and end coils;
FIG. 132 is an end view of the coils shown in FIG. 131;
FIG. 133 is a side view of mating uncanted, circular intermediate and end coils;
FIG. 134 is an end view of the coil shown in FIG. 133; and
FIG. 135 is a side view of an assembled, uncanted circular coil coil spring.
DETAILED DESCRIPTION
It should be appreciated that the drawings include specific spring angles and in many cases, dimensions and the specific references are set forth by way of example only and are not be construed as limiting in any way the breadth of the present invention. The specific dimensions are provided for reference and not repeated in the specification for the sake of clarity.
Turning now to FIGS. 1-3, there is shown spring apparatus 10 which includes a coil spring 12 having a plurality of intermediate coils 14, 16 canted along a centerline 18 of coil spring 12.
As more clearly shown in FIGS. 4 and 5, each coil 12, 14 includes a leading portion 22, 24 disposed at a front angle 26, 28 along a normal line 30 to the centerline 18. As shown in FIGS. 4 and 5, these intermediate coils have a front angle, for example purposes only, of 30°. Each of the intermediate coils 12, 14 has a trailing portion 34, 36 disposed at a back angle 40, 42 to the normal line 30.
As most clearly shown in FIGS. 2-5, end coils 46, 48 of the spring apparatus are congruent, or continuous, with the plurality of intermediate coils 12, 14 and are-disposed at ends 52, 54 of the intermediate coils 12, 14. As shown in FIGS. 4 and 5, each of the end coils, 46, 48 include trailing portions 58, 60 disposed at back angles 62, 64 which are different from the back angles 40, 42 of the intermediate coils.
Alternatively, the back angles 40, 42 may be the same and the front angles 26, 28, different from one another.
This difference in back angles enables the end coils 46, 48 to be threaded to one another in a clockwise manner illustrated by the arrow 68 in FIG. 1 when the end coil 48 is assembled into the end coil 46 in the direction of the arrow 70, as shown in FIG. 1.
More particularly, as shown in FIGS. 4 and 5, the end coil trailing portions 58, 60 have a decreasing back angle along a length of the end coil measured along a centerline 18.
As also illustrated in FIGS. 1-5, one or more of the end coils 46, 48 may be tapered, and as is most easily seen in FIGS. 4 and 5, the end coils may be tapered asymmetrically to the centerline 18. Thus, the end coils 46, 48 may be threaded, and the tapered ends, along with the difference back angle, provide a friction interference.
As more clearly shown in FIGS. 6, 7 and 8, the intermediate and end coils may be elliptical in which there is a touching or interference between the end coils all around the periphery, as indicated by the shading 72. FIGS. 6, 7 and 8 show respectively a first coil 78 on the end coil 46, a second coil 80 on the end coil 46, and a third coil 82 on the end coil.
Because of the tapered nature of the end coils 46, 48, the height of the intermediate coils 14, 16 enable compression of the spring assembly 10 as indicated by the arrows 86 in FIG. 1 without interference from the end coils 46, 48, thus maintaining the load deflection characteristics of the intermediate coils 14, 16 across the union thereof provided by the end coils 46, 48.
Turning now to FIG. 9, there is shown another embodiment 90 of the present invention, having intermediate coils 92, 94 with end coils 96, 98 as more clearly set forth in FIGS. 10-13. As most clearly shown in FIGS. 14-16, end coils 100, 102 are elliptical. As shown in FIG. 11, at least one end coil 106 is offset in order to provide a three-area point contact, or locking point for reducing the deflection load of the spring 90 in the area of the coupled end coils 96, 98. As shown in FIG. 9, the three areas are locking points, upper locking point 108; a lower back angle, locking point 110; and a lower front angle, locking point 112 (see also FIGS. 14-16). These locking points are achieved when the end coil 102 is threaded into the end coil 100 in the direction of the arrows 114, 116, as shown in FIG. 9. The assembly is further facilitated by the tapered end coils 98 as indicated by the lead lines 120 shown in FIG. 9.
Turning now to FIGS. 17-24, there is shown yet another embodiment 124 of the present invention similar to that shown in FIGS. 9-16, which includes intermediate coils 126, 128 and end coils 130, 132 with the end coil 132 tapered, as indicated by the arrow 134 shown in FIG. 17. Individual offset coils 138, 140, 142, 144, most clearly seen in FIG. 19, provide six locking areas or points which are staggered axially, the points being illustrated at points 148, shown in FIG. 21. The contact points are further illustrated in FIGS. 22--24. As hereinabove described in connection with the embodiment 90, the contact points occur on assembly of the end coil 132 into the end coil 130 by clockwise rotation, indicated by the arrows 150 in FIG. 17, as the end coil 132 couples into the end coil 130, as shown by the arrow 152 in FIG. 17.
The staggered contact area arrangement enables compression of the spring assembly without significant change in its load deflection characteristics in the area of the coupling end coils 130, 132.
Turning now to FIG. 25, there is shown yet another embodiment 156 of the present invention, with the intermediate coils 158, 160, 162, 164 (see FIGS. 26 and 27). This embodiment features an end coil 164 having a smaller coil height than the coil height of the intermediate coils 160 to permit greater deflection of the intermediate canted coils 160 along a minor axis, that is, the end coil 164 is "stepped down" from the intermediate coil 160. It should be appreciated that, while the coils are shown as having a right-hand thread, they may also be formed with a left-hand thread.
As illustrated in FIGS. 30-33, contact locking area is along the major axis 164 due to the protruding configuration of individual end coils 166, 168 (see FIG. 27).
It is to be appreciated that the end coils 162 have a diameter equivalent to the intermediate coils 158, as shown in FIG. 26, while only the end coils 164 have a smaller, or step down, diameter, as shown in FIG. 29. As hereinbefore discussed, variable back angles, as illustrated on the diagram, create interference and the locking grip between the end coils, as illustrated in FIGS. 30-33. This unlocking occurs when the end coils 162, 164 are assembled by a clockwise winding, as indicated by the arrow 172, as shown in FIG. 25, as the end coil 164 is inserted into the end coil 162 in the direction of the arrow 174, also shown in FIG. 25. This assembly is suitable for end coils which are wound in a counterclockwise direction, as indicated by the arrows 176 in FIGS. 30-33.
It should be apparent that due to the reduced diameter of the end coils 164, deflection of the spring assembly embodiment 156, as indicated by the arrows 176 along the minor axis 180 (see FIGS. 30-33), is possible without significant change in the load deflection characteristics of the spring assembly 156 in the area of the coupled end coils 162, 164. This embodiment is particularly suitable when deflection of the end coils 158, 160 along the minor axis 180 is desired with threading locking. The deflection of the coils at the locking ends result in higher force and greater range of deflection of the intermediate coils 160, without substantial change.
Yet another embodiment 186 of the present invention is shown in FIGS. 34-41, which includes intermediate coils 188, 190 and end coils 192, 194.
As shown in FIG. 35 and as most clearly evident in FIG. 39, the end coils 192 include at least one individual round coil 196 to provide a deflection stop; and an elliptical locking coil 198 is extended from the intermediate coils 190 with variable back angles 200, 202 (see FIG. 38). To create interference, there is a reverse locking grip between the end coils.
The deflection stop occurs when the intermediate coils are compressed down to the diameter of the round coils in the direction of arrow 204, as shown in FIG. 34. In this embodiment, the end coils 194 are tapered asymmetric to the centerline 206 to the intermediate coils 188, 190 and spring assembly 186. Locking is provided by engagement areas 208, 210, as shown in FIG. 40, provided by the coil 198 contact with intermediate coil 186 (see FIG. 40). Again, assembly is accomplished by rotating the end coil 194 into the end coil 192 as indicated by the arrow 212 in FIG. 34, causing engagement of the end coil 194 into the end coil 192 in the direction of arrow 214. In this embodiment, a locking end 215, end coil 191 provides a stop as indicated by position 214 in FIGS. 34 and 41 by contact with a first individual end coil 216, four coils wound in a counterclockwise manner, as indicated by the arrow 222 in FIGS. 39-41. Thus, the spring assembly 186 is assembled by threading the end coils 192, 194 together until positive stop is encountered.
Turning now to FIGS. 42-50, there is shown an alternative embodiment 220 of the spring assembly, or apparatus, wherein intermediate coils 222, 224 and end coils 226, 228 are canted along a centerline 230 with each intermediate coil 224 having a leading portion 234 disposed at a front angle 236 to a normal line 238 and a trailing portion 242 disposed at a back angle 234 to the normal line 238. Preferably, the intermediate coils 222, 224 and end coils 226, 228 are elliptical, and an elliptical shape of at least one individual end coil 248 includes extended portions 250, 252 (see FIG. 45) for causing the end coils 226, 228 to snap together with the portions 250, 252 extending exterior to the circumference of end coils 226.
Referring specifically to FIGS. 49 and 50, this provides for engagement between the end coils at alternate selected points 260, 262.
Yet another embodiment 266 of the present invention is shown in FIGS. 51-59, which includes intermediate coils 266, 268 and end coils 270, 272.
This embodiment 266 is similar to embodiment 220, shown in FIGS. 42-50, except that two individual end coils 276, 278 have a coil height measured along a minor axis 280 (see FIGS. 57-59) which is substantially smaller than an intermediate coil height measured along the minor axis. This provides for four contact areas 282, 284, 286, 288, as shown in FIGS. 57-59.
Another distinguishing difference between the embodiments 220, 266 is that the location of the leading end coil 292 of the spring apparatus 220 has an end 294, as shown in FIGS. 45 and 48, which is disposed in a lower left quadrant (see FIG. 48) whereas a leading end coil 300 of the spring apparatus 266 has an end 302 disposed in an upper right quadrant, as shown in FIGS. 54 and 57.
Also, as shown in FIGS. 50 and 59, the end coils 226, 270, respectively, provide positive stops upon assembly, the position of which is indicated at 306 and 308, respectively, in FIGS. 50 and 59.
Alternative embodiments 310, 312, 314, 316, 318 and 320, in accordance with the present invention, are shown respectively in FIGS. 60-71.
As shown in FIGS. 60 and 61, embodiment 310 includes circular intermediate coils 322 with elliptical end coils 324. The embodiment 312 in FIGS. 62 and 63 includes square intermediate coils 326 and elliptical snap-on end coils 328.
The embodiment 314 shown in FIGS. 64 and 65 includes rectangular intermediate coils 330 and round snap-on end coils 332.
Turning to FIGS. 66 and 67, the embodiment 316 shown therein includes circular intermediate coils 336 with circular snap-on end coils 338. The embodiment 318 shown in FIGS. 68 and 69 includes elliptical canted intermediate coils 340 with elliptical end coils 342 which are tapered, as indicated by the arrow 334, and include three locking points indicated at 346.
FIGS. 70 and 71 illustrate the embodiment 320 which utilizes elliptical intermediate coils 350 and elliptical end coils 352 for providing screw-in engagement, with two locking points located at opposite ends of the next-to-the-last leading coils, similar in construction to FIG. 69, but not shown.
Turning now to FIGS. 72-76, there is yet another embodiment 356, in accordance with the present invention, having intermediate coils 358, 360 canted along a centerline 362 and having leading portions 364 and trailing portions 366, as hereinbefore describe. End coils 370, 372 are easily distinguished from earlier described embodiments in that the diameter thereof is substantially smaller than the diameter of the intermediate coils 358, 360.
Further, as most clearly shown in FIGS. 73 and 74, the end coils 370 extends outwardly from the intermediate coils 364 along the centerline and the end coil 372 is a female end coil disposed interior to the intermediate coil 360. The embodiment 356 is assembled by threading the end coil 370 into the end coil 372 until the outer portions contact and match one another. It should be evident that, because the end coils 370, 372 are substantially smaller than the intermediate coils 358, 360, deflection of the intermediate coils 358, 360, as indicated by the arrows 374, depression of the coils 358, 360 in the area of the union of the end coils 370, 372 does not affect the load deflection characteristics of the spring assembly 356. FIGS. 75 and 76 offer end views of the coils 358, 360, 370, 372 and further illustrate the freedom of movement available to the intermediate coils 358, 360.
Another embodiment 380, similar to the embodiment 356, is shown in FIGS. 77-79. The coil assembly 380 includes intermediate coils 382, 384, which may be elliptical, and end coils 386, 388, as more clearly shown in FIGS. 78 and 79.
FIG. 77 is a top view of the spring apparatus 380 while FIGS. 78 and 79 are side views of the spring apparatus 380 prior to assembly. End coils 386 extend outwardly from the intermediate coils 382 in a spaced apart manner, as shown in FIG. 78. End coils 388, disposed within the intermediate coils 384, are sized for accepting the end coils 386 in a manner described in connection with the spring apparatus 356.
Yet another embodiment 392 is shown in FIGS. 80-82, FIG. 80 being a top view at assembly of the spring apparatus 392. Similar to the spring apparatus 380, intermediate coils 394, 396 may be elliptical, as well as end coils 398, 400.
However, in the spring apparatus 392 illustrated in FIGS. 80-82, the male end coils 398 are both spaced apart and tapered, the taper being illustrated with dashed lines 402. Assembly of the spring apparatus 392 is in accordance with the assembly procedures describing the spring assembly 356.
Still another embodiment 406, in accordance with the present invention, is shown in FIGS. 83-85, with the FIG. 83 being a top view of the assembled spring apparatus 406, and FIG. 84 being a side view of an end coil 408 prior to assembly. FIG. 85 is a side view of end coil 410 prior to assembly. This embodiment 406 is similar to the spring apparatus 356 which includes abutting individual end coils 412, 414 which have a substantially smaller diameter than intermediate coils 416, 418. The end coil 408 is distinguished over the end coil 370 (see FIG. 73) in that in addition to abutting, the end coils 412, 414 are tapered as indicated by the dashed line 420.
FIG. 86 shows the top view of another embodiment 422 of the present invention, which includes intermediate coils 424, 426 congruent with end coils 428, 430. This spring arrangement 422 is similar to the spring arrangement 406 except that the end coils 428 are spaced apart and tapered, as indicated by the dashed line 432.
Yet another embodiment 434, in accordance with the present invention, is illustrated in FIGS. 89a, 89b, 90a, 90b, and 91, FIG. 91 being a cutaway side view of the assembled spring apparatus 434. The spring apparatus 434 includes square intermediate coils 436, 438, and is most clearly shown in FIGS. 89b and 90a around end coils 440, 442.
Turning now to FIG. 92, there is shown yet another embodiment 446 before assembly, generally showing intermediate coils 448, 450, which may be elliptical, end coils 452, 454, which are abutting and of substantially smaller diameter than the intermediate coils 448, 450, along with an insert coil 456.
In this embodiment, both the end coils 452, 454 are female and the insert coil 456 includes male portions 458, 460 sized for insertion into the end coils 452, 454 with center coils 462 providing a stop. A side view of the spring apparatus 446 is shown in FIG. 93 prior to assembly, with each of the characterizing angles of the intermediate coils 448, 450, end coils 452, 454, as well as the insert coil 456 being indicated in the figure.
FIG. 94 shows a cutaway spring assembly 446 at maximum deflection when compressed in the direction of arrows 464 showing the end coils 452, 454 in crosssection.
It should be evident from FIG. 94 that the reduced diameter of the end coils 452, 454, as well as the insert coils 456, enable the intermediate coils to deflect without bearing against the same and therefore enabling the intermediate coils a constant load deflection characteristic throughout a length thereof.
In this embodiment, the end coils 452, 454 may be round, as shown in FIGS. 95 and 96.
Still another embodiment 468 of the present invention is shown in FIGS. 97-102, with FIG. 97 being a top view of the spring assembly 468. The spring assembly 468 is similar to the spring assembly 380 shown in FIGS. 77-79 with an important distinguishing feature, as hereinafter set forth.
The spring apparatus 468 includes intermediate coils 470, 472, with end coils 474, 476, which may be circular, as shown in FIGS. 100 and 101. Specific angular definition of the intermediate coils 470, 472 and end coils 474, 476 are set forth directly on FIGS. 98 and 99, which are side views of the end coils 474, 476, respectively.
In this embodiment 468, the end coils 474 protrude outwardly from the intermediate coils 470 along a centerline 478. In contrast with the assembly 380, as shown in FIGS. 77-79, the end coils 476 comprise female coils extending outwardly from the intermediate coils 470 and sized for engagement with male coils 474. The size differential is illustrated in FIGS. 100 and 101.
Because the diameters of the end coils 474, 476 are substantially smaller than the diameters of the intermediate coils 470, 472, the intermediate coils may be deflected (as shown in FIG. 102) without interference by the coupling end coils 474, 476. Thus, a constant load deflection characteristic of the intermediate coils is maintained throughout the length of the spring assembly 468.
Turning now to FIGS. 103-108, there is shown another embodiment 482 of the present invention generally including intermediate coils 484, 486 and end coils 488, 490. FIG. 103 is a top view of the assembled spring assembly 482, while FIGS. 104 and 105 are side views of a separated assembly, detailing the front angles 494, back angles 496, as hereinbefore described in connection with earlier presented embodiments of the present invention.
FIGS. 106 and 107 are end views of the end coils 488, 490, respectively, and FIG. 107 most clearly shows a triangular configuration of the end coil 490 which is a feature of the assembly 482. A dotted line at 492 indicates interference locations between the end coils 488, 490 to provide locking of the end coils 488, 490 together, resulting in the spring assembly 482.
FIG. 108 is a cutaway view of the spring assembly 482 at maximum deflection under a force indicated by the arrows 496. It can be seen that in addition to the difference in diameter of the end coils 488, 490 and the intermediate coils 484, 486, the triangular shape of the end coil 490 further enables the compression of the intermediate coils 484, 486, without interference from the end coils 488, 490, thereby not interfering with the load deflection characteristics of the intermediate coils.
FIGS. 109-115 show still another embodiment 510 of the present invention which is similar to the spring assembly 482, shown in FIGS. 103-108.
As shown assembled is a top view of a spring assembly 510 in FIG. 109, generally including intermediate coils 512, 514, and, as more clearly shown in FIGS. 110 and 111, end coils 516, 518. Similar to FIGS. 104 and 105, FIGS. 110 and 111 show the specific configuration of the intermediate coils 512, 514 and end coils 516, 518.
FIG. 112 is an end view of the round end coil 516, which is similar to the end coil 488 of the spring assembly 482 with a greater number of convolutions.
FIG. 113 illustrates the spring assembly 510 at maximum deflection, showing, as also hereinabove set forth with other embodiments of the present invention, deflection of the intermediate coils 512, 514 without interference from the end coils 516, 518.
FIGS. 114 and 115 illustrate the triangular configuration of the end coil 518, which is similar to the end coil 492 of the spring assembly 482, with a greater number of convolutions. Also shown in FIGS. 114 and 115 are dotted lines 522, 524 depicting interference locations between the end coils 516, 518 which provide locking of the spring assembly 510, as illustrated in FIGS. 109 and 115.
FIGS. 116-120 show still another embodiment 530 of the present invention, generally including a plurality of intermediate coils 532, 534 canted along a centerline 536 of the coil spring 530 with each coil 532, 534 having a corresponding leading portion 538, 540, disposed at front angles 542, 554 to normal lines 546, 548 to the centerline 536, and trailing portions 550, 552, disposed at back angles 554, 556 to normal lines 558, 560 to the centerline 536. End coils 564, 566 are congruent respectively with the intermediate coils 532, 536 for providing a joining of the intermediate coils to form the spring assembly, as shown in top view in FIG. 116.
Importantly, the end coils 564 include at least one hook coil 570, including an end bent latch portion 572 (see FIGS. 116 and 117) and abutting female coils 574 having a substantially smaller diameter than intermediate coils 532, 534. Locking is provided when the bent latch portion 572 protrudes through the internal female coils 574, as shown in FIGS. 116 and 121. End views of the end coil 570 are shown in FIG. 119, while the end views of the generally circular end coils 574 are shown in FIG. 120.
A stop is provided upon latching of the two end coils 564, 566 by abutment of the intermediate coils 532, 534, as shown in FIG. 116.
FIG. 121 illustrates the advantage of the present invention by depicting the spring assembly 530 in cross-section at full deflection in response to loading in the direction of arrows 580. As illustrated, full deflection of the intermediate coils 532, 534 may be achieved without interference from the end coils 564, 566, thereby enabling a constant load deflection characteristic of the intermediate coils 532, 534 over the continuous length of the assembly 530.
It should be appreciated that all of the hereinabove recited embodiments may be filled with an elastomer or plastic, having either a solid or a hollow coil. This configuration is illustrated in FIGS. 122-130 which shown an elastomer 184 surrounding a spring assembly 586, having intermediate coils 588, 590 and end coils 592, 594. The purpose of the elastomer is to provide uniform loading, as well as sealing, in addition to providing enhancement of conductivity and electromagnetic shielding, depending upon the consistency of the elastomer exposure of one or more coils or portions of coils to enhance conductivity and/or electromagnetic shielding.
FIGS. 123 and 124 show cross-sections taken along the line A--A of FIG. 122 for a solid core elastomer 184 (see FIG. 123) and the elastomer 184 having a hollow center 598, as shown in FIG. 124. Similarly, FIGS. 125 and 126 correspond to view B--B taken from FIG. 122. FIGS. 127 and 128 show solid and hollow core elastomer 184 taken along the line C--C in FIG. 122. FIGS. 129 and 130 show solid and hollow core elastomers viewed along the line D--D of FIG. 122.
Also shown in FIGS. 126 and 128 are contacted area points 602-605, illustrating mechanical linkage between the end coils 592, 594, as hereinbefore described in greater detail.
While the present invention has been hereinabove described in terms of canted coils, it should be appreciated that the coils need not be canted. In that regard, FIGS. 131-135 illustrate an embodiment 610, in accordance with the present invention, in which intermediate coils 612, 614 are circular and not canted; and end coils 618, 620 are also circular and uncanted. FIGS. 131 and 132 show side and end views, respectively, of the intermediate coils 612 and end coils 618 whereas FIGS. 133 and 134 show side and end views, respectively, of the intermediate coils 614 and end coils 620.
FIG. 135 illustrates the assembly of the end coils 618, 620.
It should also be appreciated that in the embodiments hereinabove described that the end coils may be of the same or different configuration. That is, the elliptical end coil 324 may be used with a round end coil 332.
Although there has been hereinabove described a coil spring with ends adapted for coupling without welding, in accordance with the present invention, for the purpose of illustrating the manner in which the invention may be used to advantage, it should be appreciated that the invention is not limited thereto.
It should be further appreciated that the coupling of spring ends in accordance with the present invention is particularly suitable for springs providing bias while at the same time enabling efficient sealing, electromagnetic shielding and/or conductivity.
Accordingly, any and all modifications, variations, or equivalent arrangements which may occur to those skilled in the art, should be considered to be within the scope of the present invention as defined in the appended claims.
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Spring apparatus is provided which includes coil springs having intermediate and end coils suitable for interconnection in order to form a continuous spring which maintains a constant load-deflection characteristic over all intermediate coils unaffected by the joint end coils. This configuration therefore finds particular utility in providing bias without compromise of sealing, electromagnetic shielding and/or conductivity.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an automatic transfer apparatus for a liquid crystal display (LCD) device and a method for sensing obstacle using the same, and particularly, to an automatic transfer apparatus for an LCD device which is capable of preventing a damage on a structure of an automatic transfer apparatus due to an obstacle by mounting a sensing member which is mounted at a bottom surface of the automatic transfer apparatus to sense the obstacle on the bottom, and by previously checking an existence of the obstacle.
[0003] 2. Background of the Invention
[0004] Development of information society has gradually enhanced requirements for various types of display devices. Among various types of flat panel display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), field emission displays (FEDs), and the like LCDs are spotlighted the most to continue be developed as monitors for TV sets and desktop computers as well as monitors for notebook computers.
[0005] The LCD device may broadly be divided into LCD panels for displaying images and a driving unit for applying a driving signal to the LCD panels.
[0006] As shown in FIG. 1 , a related art LCD panel includes first and second substrates 1 and 2 which are bonded to each other with a certain space therebetween, and a liquid crystal layer 3 injected between the first and second substrates 1 and 2 .
[0007] Here, the first substrate 1 (i.e., a thin film transistor (TFT) array substrate) includes a plurality of gate lines 4 arranged in one direction by a certain interval therebetween, a plurality of data lines 5 arranged by a certain interval therebetween in a direction perpendicular to each gate line 4 , a plurality of pixel electrodes P formed in a matrix shape at each pixel region defined at an intersection between the gate lines 4 and the data lines 5 , and a plurality of TFTs which are switched by a signal from the gate line 4 to transfer a signal from the data line 5 to each pixel electrode P.
[0008] Furthermore, the second substrate 2 (i.e., a color filter substrate) includes a black matrix layer 7 for preventing light from being transmitted to regions rather than the pixel regions, R, G and B color filter layers 8 for rendering color and a common electrode 9 for implementing images. Here, the common electrode 9 may be formed on the first substrate 1 in an LCD device employing a horizontal electric field mode.
[0009] The LCD device having such structure is fabricated by processes for fabricating a TFT array on the first substrate 1 , fabricating a color filter layer on the second substrate 2 , bonding the first and second substrates 1 and 2 to each other, injecting a liquid crystal between the bonded substrates 1 and 2 and sealing the liquid crystal, testing and repairing each LCD panel in which the liquid crystal has been injected, and mounting a back light or the like in each LCD panel with a good quality and mounting a driving circuit to fabricate a liquid crystal display module.
[0010] The substrates undergoes such various processes to completely be the LCD device. The substrates are transferred to devices which perform each process by use of an automatic transfer apparatus.
[0011] With reference to FIGS. 2 and 3 , explanation will now be given for a related art automatic transfer apparatus used to transfer the substrates to the devices for performing each process upon fabricating an LCD device.
[0012] FIG. 2 is a schematic view showing a related art automatic transfer apparatus having a cassette.
[0013] FIG. 3 is a schematic view showing the related art automatic transfer apparatus having the cassette, which shows a case that there is an obstacle on a movement direction.
[0014] Referring to FIG. 2 , a related art automatic transfer apparatus 10 includes a mounting unit 15 for placing a cassette 31 in which a plurality of substrates are received in order to perform each process, and a moving unit 11 disposed at a bottom of the mounting unit 15 and moving within a designated interval, namely, moving toward each processing device by use of rotational movement members 13 . A distance T 1 is a height between the outer bottom surface 41 and the lower portion of the moving unit 11 . The mounting unit 15 of the automatic transfer apparatus 10 has a robot arm 21 which is used to load the cassette 31 which is positioned at an input port (not shown) and an output port (not shown) of a stoker (not shown) directly on the mounting unit 15 or to unload the cassette 31 which has been loaded on the mounting unit 15 to the stoker.
[0015] In a state that the automatic transfer apparatus 10 is moved toward each processing device in order to perform each process, the cassette 31 which has been loaded on the mounting unit 15 by the robot arm 21 or the cassette which is placed at the input port or output port is moved to each processing device or to the stoker.
[0016] However, as shown in FIG. 3 , it is impossible for the automatic transfer apparatus 10 according to the related art to sense an obstacle 51 on the bottom out of the range in which a front of the obstacle 51 can be sensed. Here, T 2 is a thickness of the obstacle 51 .
[0017] Therefore, impurities come into the bottom of the automatic transfer apparatus 10 , which causes interference with a lower structure of the automatic transfer apparatus 10 , resulting in problems in devices. That is, when an obstacle which is not sensed at a bottom of a movement detecting sensor or the moving unit is sucked into the bottom of the automatic transfer apparatus, damages may occur on the bottom structure of the automatic transfer apparatus.
SUMMARY OF THE INVENTION
[0018] Therefore, an object of the present invention is to provide an automatic transfer apparatus for a liquid crystal display (LCD) device and a method for sensing obstacle using the same capable of preventing a damage on a structure of an autom atic transfer apparatus by mounting a device for sensing an obstacle on a bottom of the automatic transfer apparatus. To achieve these and other advantages and in accordance with the purpose of the pr esent invention, as embodied and broadly described herein, there is provided an aut omatic transfer apparatus for a liquid crystal display device comprising: a mounting u nit; a moving unit disposed at the mounting unit; a sensing member disposed at the moving unit for sensing an obstacle; and an alarm signal unit for generating alarm signal.
[0019] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provide d a method for sensing obstalcle using an automatic transfer apparatus for a liquid cr ystal display device comprising: providing a mounting unit; providing a moving unit disposed at the mounting unit; disposing a sensing member at the moving unit for se nsing an obstacle; and disposing an alarm signal unit to generate alarm signal.
[0020] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] 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.
[0022] In the drawings:
[0023] FIG. 1 is an exploded perspective view showing a part of a related art LCD panel;
[0024] FIG. 2 is a schematic view showing a related art automatic transfer apparatus in which a cassette is mounted;
[0025] FIG. 3 is a schematic view showing the related art automatic transfer apparatus in which the cassette is mounted, which shows a case that there exists an obstacle on a movement direction;
[0026] FIG. 4 is a schematic view showing an automatic transfer apparatus for an LCD device according to an one embodiment of the present invention;
[0027] FIG. 5 is a lateral view showing the automatic transfer apparatus according to the one embodiment of the present invention, which shows an obstacle sensing member.
[0028] FIG. 6 is a schematic view showing an obstacle sensing member mounted at a bottom portion of the automatic transfer apparatus according to the one embodiment of the present invention; and
[0029] FIG. 7 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to the one embodiment of the present invention.
[0030] FIG. 8 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to an another embodiment of the present invention.
[0031] FIG. 9 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to further another embodiment of the present invention.
[0032] FIG. 10 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to further another embodiment of the present invention.
[0033] FIG. 11 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to further another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0034] Description will now be given in detail of the present invention, with reference to the accompanying drawings.
[0035] Hereinafter, an automatic transfer apparatus for an LCD device according to the present invention will be explained in detail with reference to the attached drawings.
[0036] FIG. 4 is a schematic view showing an automatic transfer apparatus for an LCD device according to an one embodiment of the present invention, and FIG. 5 is a lateral view of the automatic transfer apparatus according to the one embodiment of the present invention, which shows an obstacle sensing member.
[0037] FIG. 6 is a schematic view showing an obstacle sensing member at a bottom of the automatic transfer apparatus according to the one embodiment of the present invention.
[0038] FIG. 7 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom of the automatic transfer apparatus according to the one embodiment of the present invention.
[0039] As shown in FIGS. 4 and 5 , an automatic transfer apparatus 100 according to the present invention includes a mounting unit 115 for placing a cassette 141 in which a plurality of substrates are received in order to perform each process, and a moving unit 111 disposed at a lower portion of the mounting unit 115 and moving within a designated interval (section), namely, toward each processing device, by rotational movement members 113 .
[0040] Furthermore, the mounting unit 115 of the automatic transfer apparatus 100 is provided with a robot arm 131 , which is used to load the cassette 141 placed at an input port (not shown) or an output port (not shown) of a stoker (not shown) to the mounting unit 115 or to unload the cassette 141 loaded on the mounting unit 115 to the stoker (not shown).
[0041] In a state that the automatic transfer apparatus 100 is moved toward each processing device by virtue of the movement of the automatic transfer apparatus 100 in order to perform each process, the cassette 141 which has been loaded on the mounting unit 115 by the robot arm 131 or the cassette which is placed at the input port or output port is moved to each processing device or the stoker.
[0042] A sensing member is provided within the moving unit 111 of the automatic transfer apparatus 100 . The sensing member includes two tape sensors 121 and 123 and an obstacle sensing bar 125 . The one tape sensor 123 of the two tape sensors 121 and 123 is coupled to the obstacle sensing bar 125 . One end of the obstacle sensing bar 125 is protruded downwardly to outer bottom surface 151 by a predeter mined distance T 3 . The distance T 3 is a height between the outer bottom surfa ce 151 and the end portion of the obstacle sensing bar 125 . Further, the automatic transfer apparatus 100 includes an alarm signal unit (not shown) for generating alarm sigal when the obstacle is sensed by the sensing member.
[0043] As shown in FIGS. 5 , 6 and 7 , the obstacle sensing bar 125 is protruded enough to sense an obstacle 161 having a thickness T 2 smaller than a height T 1 between the moving unit 111 of the automatic transfer apparatus 100 and the outer bottom surface 151 . The obstacle sensing bar 125 is protruded downwardly to outer bottom surface 151 . And the obstacle sensing bar 125 maybe incline in a forward or backward direction. The obstacle sensing bar 125 is configured to be pushed back when it is contacted with the obstacle 161 . When the obstacle sensing bar 125 is moved by being pushed back by the obstacle 161 , the tape sensor 123 coupled to the obstacle sensing bar 125 is simultaneously moved in a direction opposite to that of the obstacle sensing bar 125 , to be in contact with the other tape sensor 121 corresponding thereto.
[0044] Hence, as shown in FIG. 7 , when the automatic transfer apparatus 100 is moved forwardly, if the obstacle 161 placed at the front area of the automatic transfer apparatus 100 is in contact with the obstacle sensing bar 125 , the obstacle sensing bar 125 is pushed back by the obstacle 161 . Then the tape sensor 123 coupled to the obstacle sensing bar 125 is moved in the opposite direction to that of the obstacle sensing bar 125 to be in contact with the other tape sensor 121 . The tape sensors 121 and 123 which have been contacted to each other start to be operated, thereby giving the automatic transfer apparatus 100 to a pause and operating an alarm by the alarm singal unit (not shown).
[0045] Afterwards, an operator removes the obstacle 161 sensed at the bottom of the automatic transfer apparatus 100 to continue to perform the operation.
[0046] Meanwhile, another embodiments of the present invention is described as follows.
[0047] FIG. 8 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to an another embodiment of the present invention.
[0048] FIG. 9 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to further another embodiment of the present invention.
[0049] FIG. 10 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to further another embodiment of the present invention.
[0050] FIG. 11 is a schematic view showing an operational state of the obstacle sensing member mounted at the bottom portion of the automatic transfer apparatus according to further another embodiment of the present invention.
[0051] As shown in FIG. 8 , a sensing member according to an another embodiment of the present invention includes two tape sensors 221 a and 221 b spaced apart from each other and an obstacle sensing bar 225 coupled to a tape sensor portion 223 . Accordingly, the tape sensor portion 223 coupled to one of two tape sensors 221 a and 221 b.
[0052] Accordingly, one of the tape sensors 221 a and 221 b and the sensor portion 223 which have been contacted to each other start to be operated, thereby giving the automatic transfer apparatus to a pause and operating an alarm by the alarm signal unit (not shown).
[0053] Afterwards, an operator removes the obstacle 261 sensed at the bottom of the automatic transfer apparatus to continue to perform the operation.
[0054] As shown in FIG. 9 , a sensing member according to further another embodiment of the present invention includes tape sensors 321 and 323 is in contact with each other and an obstacle sensing bar 325 coupled to a tape sensor 323 . Accordingly, when the obstacle sensing bar 325 is pushed back by the obstacle 361 , the tape sensor 323 is not contacted with the tape sensor 321 .
[0055] Accordingly, the tape sensors 321 and 323 have been not contacted to each other start to be operated, thereby giving the automatic transfer apparatus to a pause and operating an alarm by the alarm singal unit (not shown).
[0056] Afterwards, an operator removes the obstacle 361 sensed at the bottom of the automatic transfer apparatus to continue to perform the operation.
[0057] As shown in FIG. 10 , a sensing member according to further another embodiment of the present invention includes a tape sensor 421 , and a obstacle sensing bar 425 spaced apart from the tape sensor 421 . Further, the obstacle sensing bar 425 includes another tape sensor portion 425 a which is in contact with the tape sensor 421 . The obstacle sensing bar 425 and the another tape sensor 425 a comprise a single body.
[0058] Accordingly, the tape sensors 421 and 425 a have been contacted to each other start to be operated, thereby giving the automatic transfer apparatus to a pause and operating an alarm by the alarm singal unit (not shown).
[0059] Afterwards, an operator removes the obstacle 461 sensed at the bottom of the automatic transfer apparatus to continue to perform the operation.
[0060] As shown in FIG. 11 , a sensing member according to further another embodiment of the present invention includes a obstacle sensing bar 525 . The obstacle sensing bar 525 has a sensor function for sensing the obstacle.
[0061] Accordingly, when the obstacle sensing bar 525 senses the obstacle 561 , thereby giving the automatic transfer apparatus to a pause and operating an alarm by the alarm singal unit (not shown).
[0062] Afterwards, an operator removes the obstacle 561 sensed at the bottom of the automatic transfer apparatus to continue to perform the operation.
[0063] As aforementioned, several effect can be expected by use of the automatic transfer apparatus for the LCD device according to the present invention.
[0064] Regarding the automatic transfer apparatus for the LCD device according to the present invention, the sensing bar capable of sensing the obstacle is mounted at the automatic transfer apparatus. Accordingly, the sensing bar can be used to easily sense and remove the obstacle while moving the automatic transfer apparatus, whereby such small obstacles which have not been detected can be sensed to accordingly be possible to protect the lower structure of the automatic transfer apparatus from being damaged due to the small obstacles.
[0065] Hence, upon using the automatic transfer apparatus according to the present invention, the obstacles can previously be detected to make the automatic transfer apparatus pause, thereby ensuring high stability of the automatic transfer apparatus.
[0066] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.
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An automatic transfer apparatus for a liquid crystal display device comprising a mounting unit for placing a cassette in which a plurality of substrates are received, a moving unit disposed at a lower surface of the mounting unit and moving within a designated interval or section, and a sensing member mounted in the moving unit for sensing an obstacle, wherein the sensing member for sensing an obstacle at a bottom is disposed at the lower surface of the automatic transfer apparatus so as to enable a previous checking an existence of the obstacle, thereby preventing a structure of the automatic transfer apparatus from being damaged due to the obstacle.
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FIELD OF INVENTION
The present invention relates to synthetic fibers, and in particular relates to improvements in polyester textile fibers, and especially a novel method for producing polyester bi-component fibers and filaments from the modified and unmodified melt of one and the same polyester, and to the fibers and filaments which can be produced by means of this novel method.
BACKGROUND
The development of the first synthetic bi-component fibers and of the special spinnerets and the methods required to produce such bi-component fibers was started approximately 40 years ago. Such fibers are composed of two polymers of different chemical and/or physical structures which are connected with each other. Depending on the geometric arrangement of the two components in the fiber, distinctions between the types of side- by-side (S/S), core/cover (C/C) and matrix/fibrils (M/F) are made. Polymerswhich are of different types, the same types or modified can be considered as components. The following types of material pairings are known in the field of polyesters:
two different homo-polyesters, for example PET (polyethylene terephthalate) and PBT (polybutylene terephthalate), or PET and PPT (polypropylene terephthalate)
one homo-polyester and one copolyester,
two different co-polyesters,
two polyesters of the same chemical composition, but of different solvent viscosity,
The first three combination options have the disadvantage that respectively two different polyesters are required for this, which must be stored, processed and melted in separate systems, i.e. two crystallizers, two dryers and two extruders are required. Added to this are the problems of crystallization and drying of copolyesters, which become clearly more tacky beginning with only a few mol-% of comonomer parts and which, in the case of amorphous copolyesters, can only be dried below their glass transition temperature, which results in very long drying times.
The fourth option can also be performed "in line" (see DD 80515 or the equivalent ZA 6904544) or as in DE 1 938 291 or its equivalent U.S. Pat. No. 3,671,620, wherein an intermediate product melt stream of low viscosity is branched off the polycondensation system in a continuous direct spinning system.
A further process variant consists in lowering a partial polyester stream to the desired low viscosity by glycolysis in that ethylene glycol, for example, is metered into the corresponding melt pipe or into the separate melt extruder. The "two viscosities" variant is only used in the production of self-crimping fibers and filaments. However, this is problematical, since the melt stream bends when exiting the capillaries of the spinneret because of the different, side-by-side located viscosities. If a defined critical viscosity difference is exceeded, spinning no longer can take place because at that point the fibrils are bent so strongly that they adhere to the nozzle plate. For example, hollow SIS PET fibers can still be safely spun at a maximum difference in relative viscosity (with the same melting temperature of the two halves) of 0.10 (relative viscosity measured at 1% in m-cresol at 20° C., for example initial viscosity=1.60 and degraded viscosity of the partial stream=1.50). With S/S fibers which are not hollow, the permissible difference is even less for reasons of physics.
To realize spinning at greater viscosity differences, it has been proposed to make the nozzle openings asymmetric in such a way that the melt fiber side with the lower viscosity has the greater contact surface with the inner wall of the bore in order to slow the flow speed on that side in such manner and to prevent diversion (see GB 1 091 367 or its equivalent U.S. Pat. No. 3,408,433). However, such nozzle plates are too expensive, both because of their special construction and, in operation, because of the reduced hole density, i.e. reduced number of threads produced.
The use of caprolactone as a possible co-component for co-PET for producing filaments with greater shrinking is mentioned in U.S. Pat. No. 3,927,167. However, the subject of this patent is a mixed yarn, which becomes bulky with heat treatment and is obtained by a combination of simultaneously, but separately melt-spun individual PET and co-PET threads into a yam. This patent does not pertain to bi-component spinning, and the co-PET granules are produced in the conventional manner.
SUMMARY OF INVENTION
It is an object of the invention to develop a cost-effective method which generally simplifies the production of polyester bi-component threads and thereby makes them more economical for industrial production, and improves the spinnability of the S/S types at the nozzle. In general, bi-component fibers and filaments are produced by means of "in line" modification of a partial stream with a co-monomer from the substance class of lactones, and spinning of the unmodified and modified melt stream by means of at least one bi-component spinneret pack.
Based on only one and the same basic type of polyester, and in accordance with the present invention, a portion of the melt is continuously modified "in line" with a lactone co-monomer prior to spinning, and the modified and unmodified melt streams are supplied to one or several bi-component spinneret packs and spun into hi-component threads and, in the case of S/S fiber cables, self-crimping is performed at the end.
It was surprising that only a single polymer was sufficient, in place of the two required polymers up to now, and that in spite of this, bi-component threads suitable for the intended use were obtained without production problems. In spite of the "in line" modification of a partial stream required by the invention, the viscosity difference with the unmodified polyester must not exceed certain limits, as mentioned, and at the same time it must be possible to perform the modification within a very short time, i.e. in less than 30 minutes, and the polymer properties must change to a sufficient degree in the process.
Lactones capable of reaction, in particular ε-caprolactone, have surprisingly shown themselves to be suitable for the modification of polyester during bi-component spinning. Introduced as a monomer into the polyester melt, lactones which are suitable in accordance with the present invention react under pressure with the polyester in a surprisingly short time, i.e. less than 30 minutes, at unusually high temperatures, which are per se considered to be harmful in accordance with the prior art, of more than 260° C., in particular 265° to 310° C., preferably 270 to 295° C., and form a co-polyester. The reaction time for modification is preferably maximally 20 minutes, and particularly preferred are 3 to 15 minutes.
Further than that, in the present process the relative viscosity as a measure for the molecular weight remains surprisingly constant and the melt viscosity decreases only slightly. In accordance with the invention, the mutual processing of modified and unmodified polyesters is possible for the first time for the smallest units of a product structure (bi-component threads), wherein a relatively strong "in line" modification is possible in bi-component spinning, without interfering with the spinnability because of a too strong bending of the threads exiting the nozzle.
BRIEF DESCRIPTION OF DRAWING
An advantageous embodiment of the novel method principle for producing polyester bi-component threads according to the present invention is schematically represented in FIG. 1.
DETAILED DESCRIPTION OF EMBODIMENTS
FIG. 1 is thus a schematic view of a preferred system according to the present invention wherein the reference numerals indicate:
1 Polyester melt stream
2 Branching of the stream 1 into two partial streams
3 Metering in the lactone into the partial stream to be modified
4 Static mixer
5 Modified partial stream (copolyester)
6 Unmodified partial stream
7 Spinning pump for the modified partial stream
8 Spinning pump for the unmodified partial stream
9 Spinneret pack with spinneret for bi-component spinning
10 Bi-component threads (initially in the form of a melt)
The polyester stream 1 preferably is constituted by polyester terephthalate (PET) with at least 90, preferably 95 or more, mol-% of ethylene terephthalate units. This stream either comes from a continuous poly-condensation (during direct spinning) or from an extruder (with extruder spinning based on granules). Branching 2 preferably takes place in the melt; if there is a conventional bi-component installation with two melt extruders the polyester granules can be distributed to the two extruders (or the associated dryers) as this corresponds to branching. Metering at point 3 of the lactone, preferably ε-caprolactone, into the partial stream to be modified preferably takes place in the melt pipe at the start of the static mixer 4, in the case of two extruders, but pressureless metering into the granule inlet of the one extruder can also be carried out according to the present invention.
Processing--and/or application-stipulated additives, such as catalysts, stabilizers, dyes and UV brighteners, can selectively be dissolved in the lactone. Catalysts for speeding up ring-opening and the insertion reaction are preferably added to the lactone, for which tin (II) compounds such as tin (II) dioctoate, or zirconium (IV) compounds, such as zirconium (II) acetylacetonate, are particularly suitable.
The modified partial stream 5, a lactone co-PET, is formed by reacting the lactone with the polyester melt. Like the unmodified partial stream 6, it is supplied by means of spinning pumps 7 or 8 to the bi-component spinneret pack 9. In a production installation it is of course also possible to distribute the two melt streams 5 and 6 to several spinneret packs 9 by means of an appropriate number of spinning pumps 7 or 8. The ratio of the two streams 5 and 6 set by means of the spinning pumps is approximately 1:1 in many applications. Depending on the pressure drop in the static mixer 4, it is sometimes also advantageous to arrange the spinning pump 7 upstream instead of downstream of the static mixer.
The bi-component spinneret pack 9 with the spinneret is of an arbitrarily suitable construction for generating strand profiles such as the S/S, S/S hollow or C/C configurations. S/S hollow is a profile as represented, for example, in FIG. 2 of DD 80 515 and ZA 69 04544. The appropriate bi-component melt threads or filaments 10 exit from the spinneret and are then cooled in accordance with known methods, and thus solidified into threads, and subsequently processed in one or two stages into for example textile or carpet fibers or filaments having the desired use properties. Further processing of the threads into fibers or filaments is performed in a manner known per se, such as described in Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A10, Fibers, 3rd General Production Technology, pp. 511 to 566, D-Weinheim, 1987. Following melt spinning, the general processing steps consist of drawing, crimping and heat treatment. The methods and machines are different, depending on whether fibers or filaments (endless multifilaments) are involved. As a rule, fibers are produced in two stages, i.e. drawing separately from spinning, and are of course cut at the end.
The finished fibers or filaments can be further processed in turn for producing various articles and their applications.
Preferred variants and applications of fibers or filaments produced from the bi-component threads in accordance with the invention are, for example, with low partial stream modification, preferably approximately 4 to 12 mol-% of lactone, self-crimped SIS hollow fibers for use as filler fibers, or most preferably not more than about 11.5 mol-% lactone,self-crimped S/S filament yarns for producing curtains or fabrics. At increased modification, preferably approximately 20 to 40 mol-% of lactone, hot-melt adhesive fibers are obtained in the core/cover configuration (with the co-PET as the cover), also called binder fibers, for the thermal reinforcement of nonwovens, or analogously hot-melt adhesive filaments,
In connection with the low modification, but even more so with high modification filaments, a large advantage of the method in accordance with the present invention lies in that crystallization and drying of the tacky copolyester, which is difficult in actuality, can be omitted.
The following examples are offered illustratively:
EXAMPLE 1
Dulled PET granules of the textile type M760 of EMS-CHEMIE AG constituted the base polymer. This textile standard polyethylene terephthalate has a relative viscosity of 1.60 (measured 1% in m-cresol at 20° C.) and contains 0.4 weight-% of TiO 2 (titanium dioxide) as the dulling pigment. The granules were distributed on the two dryers respectively of melt extruders of a conventional bi-component fiber pilot spinning machine. ε-caprolactone (obtained from SOLVAY INTEROX LTD.) was metered into the granule inlet connector (at the flange between the pipe from the dryer to the extruder) of the one extruder by means of a liquid metering pump. After the ε-caprolactone concentration in respect to crimping properties and amount used had been optimized in prior tests, a metered amount of 8 mol-% (corresponds to 4.9 weight-%) in relation to the co-PET after modification (i.e. to the amount of throughput of the corresponding component at the spinneret) was set in the main run. The modified and the unmodified polyester partial streams were supplied at a ratio of 1:1 to the bi-component spinning nozzle manifold by means of spinning pumps, wherein the residence time of the melt during modification was approximately 15 minutes.
The same relative viscosity was measured at samples of the two partial streams, i.e. no reduction of the molecular weight resulted from the modification in accordance with the invention. A spinneret pack of the construction described in DE 40 22 898 A1 and its equivalent U.S. Pat. No. 5,196,211 was used for spinning, however, without the K/M intermediate plate claimed therein, because side-by-side spinning, namely hollow (with an appropriate spinneret with ε-profiles), was carried out in the instant example. The temperature of the spin melts was 280° C., and the total spinneret throughput was 1310 g/min. The 790 threads total were cooled under the spinneret by means of a central cooling device (see DE 37 08 168 C2 and its equivalent U.S. Pat. No. 4,990,297), were taken off at 1170 m/min and placed in a can. Finished staple fibers were subsequently produced from the spinning material on a pilot fiber line.
EXAMPLE 2
A filament yarn was obtained on a bi-component filament pilot plant analogously with Example 1. Dulled PET granules of the type M762 of EMS-CHEMIE AG were employed as the starting material, having a relative viscosity of 1.62 (measured 1% in m-cresol at 20° C.). ε-caprolactone in an amount of 8 mol-% (relating to the co-PET) was metered in the granule inlet connector of the one extruder. Spinning was performed side-by-side at a component ratio of 1:1 by means of a bi-component spinneret pack with 26 holes and a total throughput of 44 g/min. In this case the melt residence time of the modification was approximately 25 minutes and the melt temperature 294° C. The same relative viscosity, namely 1.585, was measured for melt samples from both partial streams, i.e. no additional reduction could be noted in the modified partial stream in comparison with the unmodified stream. Although the bending of the full threads when exiting the nozzles was greater than in Example 1 with the hollow threads, it was without any technical spinning problems.
Only when starting from as much as approximately 12 mol-% of ε-caprolactone did the threads adhere to the spinneret when the thread tension was removed. In the actual spinning test with 8 mol-% of ε-caprolactone the threads were wound up at 3200 m/min following cooling, which resulted in a POY yarn of a titer dtex 138 f 26. After drawing at a ratio of 1:1.667 in a heating channel at approximately 170° C., intense crimping developed in the bi-component yarn, which could even be increased by subsequent tensionless heat-setting.
EXAMPLE 3
This time, core/cover bi-component threads were spun, again on the fiber bi-component pilot installation as in Example 1, i.e. with the C/C preliminary plate in the spinneret pack in accordance with DE 40 22 898 A1 and a spinneret with 790 circular holes. The PET granules were the same as in Example 1. However, the partial stream for the cover component was modified with 30 mol-% of ε-caprolactone (in relation to the co-PET), wherein tin (II) dioctoate at a concentration of 100 ppm in relation to the elementary tin had been dissolved as catalyst. In spite of the strong modification, the threads exiting the nozzles of the remained straight to a large degree because of their concentric cross section. The total throughput was set to 980 g/min (2×490 g/min), which corresponded to a melt residence time of approximately 20 minutes at a temperature of 280° C. The threads were cooled by means of a central quenching unit, taken off at 1200 m/min and stored in a can. Subsequently finished, hot-melt adhesive staple fibers, crimped in a stuffer box, were produced on a pilot fiber drawing line, the cover of which had a DSC melting point of approximately 200° C. It was even possible to produce amorphous co-PETs of a clearly reduced adhesion temperature by a further increase of the caprolactone modification in the range of 35 to 40 mol-%.
The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. The means and materials for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation,
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A method for producing polyester bi-component threads on the basis of only one type of polyester is carded out by an "in line" modification of a partial stream with a co-monomer from the substance class of lactones, spinning of the unmodified and modified partial melt stream by means of a bi-component spinneret pack to form bi-component threads, and their further processing and use,
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BACKGROUND OF THE INVENTION
In spinning machines belts are used for the greatest variety of applications. In a rotor spinning machine according to DE 26 34 770 A1 for example, flat belts are used to remove dirt particles from a spinning station to a suction source. These dirt conveyor belts are freed from dirt by means of suction nozzles. The suction nozzles are located at the top of the conveyor belt or, in a better embodiment, on the upper and lower side of the conveyor belt. This is to ensure that as few dirt particles as possible may adhere to the conveyor belt and be again conveyed to the spinning machine. It is a disadvantage in this known device that the conveyor belt cannot be kept completely free of dirt. Therefore, dirt particles are fed to the spinning station and cause errors in the produced yarn.
Flat belts are furthermore used in draw frames to drive draw frame rollers. Here too attention must be given to great cleanliness required of the flat belts. Adhering dirt particles may cause a change in the translation conditions of the belt and thus lead to faulty drafting of the fiber slivers to be drawn.
OBJECTS AND SUMMARY OF THE INVENTION
It is a principal object of the instant invention to create a device to clean belts in spinning machines which ensures complete cleaning of the belt from adhering dirt particles. Additional objects and advantages of the invention will be set forth in part in the description which follows, or may be obvious from the description, or may be learned by practice of the invention.
According to the present invention, if the belt is taken through a suction pipe and subjected to suction, optimal cleaning of the belt is ensured. The belt is in this case subjected to suction on all sides, i.e. on the surfaces as well as on the lateral faces. The belt is thereby cleaned advantageously on all sides and dirt is prevented from being fed again to the spinning machine. Especially good cleaning is achieved if the belt is scraped off and/or brushed against the suction pipe. This mechanical influence upon the belt in addition to the pneumatic suction increases the cleaning effect.
The device to carry out the process is designed so that the suction pipe is provided with two slits. The belt is introduced into the suction pipe through these two slits and is again removed from the suction pipe through them. An excellent cleaning effect is achieved through this simple device.
It has proven to be advantageous for the slits to be oriented in the axial direction of the suction pipe. Uniform subjection of the upper and under side of the belt to suction is thereby ensured. If the slits are located at the end of the suction pipe, a very simple assembly of the suction pipe on the belts is possible. The belt can be pushed into the slits from the side without disassembling the suction pipe or the endless belt. If the end of the suction pipe is closed with a cover, good suction on the face of the belt which is away from the suction point is achieved. Furthermore, the required suction air is reduced by closing off the suction pipe by means of the cover.
Different sizes of the slits on the suction pipe facilitate the feeding of rough dirt particles into the suction pipe and reduce the overall air consumption.
By providing mechanical cleaning devices in addition to the pneumatic suction, particularly intensive cleaning is achieved. A brush which is preferably located at the slit for the exit of the belt has proven to be an advantageous mechanical cleaning device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 each show a device for the cleaning of a belt according to the invention; and
FIGS. 3 and 4 each show a suction pipe configured according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. The numbering of components in the drawings is consistent throughout the application, with the same components having the same number.
FIG. 1 shows a device for the deflection of a dirt conveyor belt in an open-end spinning machine. A conveyor belt 1 is guided around deflection rollers 2, 3, 4. Dirt particles which have accumulated at the opener rollers at the different open-end spinning stations are removed on the upper trunk of the conveyor belt 1. The dirt particles arrive at the shown deflection location at one end of the open-end spinning machine and are there sucked away for the major part by a suction nozzle 10. Following the suction nozzle 10, the conveyor belt 1 runs through a suction pipe 5. The suction pipe 5 is slit at its end, at sides facing each other, so that the conveyor belt 1 can be guided through the suction pipe. The slits 7 and 8 face each other radially in the shown embodiment. However, in case of constantly greater soiling of one side of the conveyor belt 1, the invention also provides for a suction pipe 5 with slits 7 and 8 which do not guide the belt through the center of the suction pipe 5, but guide it with a certain offset thereto. As a result the suction pipe diameter is increased on one side of the conveyor belt so that greater quantities of dirt and particles are easier to remove. The suction pipe 5 is secured to the machine frame by means of an attachment 6.
The arrangement of the suction pipe 5 as shown in FIG. 1 is especially advantageous for fine cleaning of the conveyor belt 1. Here the suction pipe 5 removes the residual dirt on the conveyor belt 1 which could not be removed by the suction nozzle 10. This involves essentially the underside and the faces of the conveyor belt 1. The advantageous result of cleaning these surfaces is that the conveyor belt does not convey any adhering dirt particles to the spinning stations of the open-end spinning machine. This prevents dirt particles, which detach themselves as a result of mechanical or pneumatic influences from the conveyor belt 1, from being carried back to the spinning station. Production of a clean, perfect yarn is thus assisted.
The slits 7 and 8 in the embodiment of FIG. 1 have substantially identical cross-sections. As a result free passage of the conveyor belt 1 through pipe 5 and uniform suction are ensured.
FIG. 2 shows an embodiment of the invention in which the suction pipe 5 ensures the complete suction of the conveyor belt 1. The cross-sections of the slits 7 and 8 are selected so that the dirt particles conveyed on the conveyor belt 1 can be sucked away. In function of the expected quantity and particle size of the dirt for instance, it is advantageous for the slit 7 to be of greater height, with respect to the conveyor belt 1, than slit 8. This ensures that the dirt particles are introduced into the suction pipe 5 and are sucked away. The smaller slit 8 causes a smaller amount of suction air to be necessary and furthermore enhances scraping of the dirt particles against the slit edge of slit 8. The removal of the dirt particles occurs in the direction of the arrow, corresponding to the direction of movement of the conveyor belt 1.
The invention is not limited to the embodiments shown. The suction pipe 5 can be used just as well for a flat belt drive on, for example, a draw frame. On a draw frame the dust and fiber density in the immediate proximity of the machine is very high. On the other hand, the greatest precision is required in the translation ratios, in particular in driving the draw-frame rollers. If fiber accumulations are deposited between deflection rollers or drive rollers and the drive belt, the translation ratio changes and the drafting of the fiber sliver does not meet requirements. For operation in the draw frame, it is therefore advantageous for the flat belts to be especially clean. The cleaning device according to the invention is very advantageous for this application. The construction of a device according to the invention in a draw frame is shown as in FIGS. 1 and 3. Instead of the conveyor belt 1, a flat belt is used in this case. A suitable flat belt drive for a draw frame is shown in DE 39 34 576 A1.
FIG. 3 shows a suction pipe 3 according to the invention in detail. The suction pipe 5 is attached to a machine, which is not shown, by means of attachment 6. The end of the suction pipe 5 away from the suction point is slit. The slits 7 and 8 are designed so that the conveyor belt 1 can be taken through them. The width of the slits 7 and 8 must be selected so that the conveyor belt 1 can be subjected to suction on its lateral face. The heights of slit 7 and 8 should be as low as possible. This is to ensure that air consumption to subject the conveyor belt 1 to suction can be reduced to a minimum. In the embodiment shown, the slit 7 is higher than the slit 8 behind it. A larger intake opening for dirt particles is thus achieved. With a reversible conveyor belt 1, i.e. with a conveyor belt which can feed dirt particles to the suction pipe 5 in one direction as well as the other, it is advantageous for the slits 7 and 8 to be of equal height. In an advantageous embodiment according to FIG. 3, the end of the suction pipe 5 is closed by a cover 9. Unnecessary suction of air through the suction pipe end is thereby avoided, and on the other hand particularly easy introduction of the generally endless conveyor belt 1 is thus ensured. The conveyor belt 1 can be introduced into the slit 7 and 8 laterally when the cover 9 is removed. The cover 9 ius then placed over the end of the suction pipe 5 and closes it off.
FIG. 4 shows an embodiment of a suction pipe 5 in which the slit 8 is provided with a brush 11. When the conveyor belt 1 moves in the direction of the arrow, this produces an excellent cleaning effect on the conveyor belt 1. The conveyor belt 1 is brought into contact with brush 11 and is constantly brushed off. The dirt brushed off from the conveyor belt 1 is sucked away directly by the suction pipe 5. The brush 11 advantageously attacks the upper side as well as the underside and also the lateral faces of the conveyor belt 1.
The suction pipe 5 is of course not limited to a round cross-section. It is thus also possible to make slits in a pipe with a rectangular cross-section and to subject a belt taken through these slits to suction and, thus, to clean it.
The invention also relates to conveyor or drive belts of machines other than the described spinning plant machines, in which much dirt is produced on the one hand, but where great precision and therefore cleanliness of the belt is required on the other hand. The belts to be cleaned can also be structured.
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 scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.
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The invention relates to a process and to a device for the cleaning of a textile machine belt by means of a suction pipe. The belt is taken through the suction pipe and is subjected to suction. The suction pipe is provided with two slits for that purpose, by means of which the suction pipe surrounds the belt.
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FIELD OF THE INVENTION
The present invention relates to slurry distributors for the control of slurry composition, building dykes and general tailing disposal from mine tailings to form a retaining area for mine tailings and concentration process water protection berms and dykes.
BACKGROUND OF THE INVENTION
It is known to provide a main large diameter pipe fed with slurry made of mine residues and having a series of small diameter spigots, which can be successively closed or opened manually on one side.
The slurry is discharged at selected points on the ground for dyke building and when the slurry pile is sufficiently high at one spigot the latter is closed and opened again after extending the branch to an adjacent location. Once a certain area has been filled with the slurry, the branches are disconnected from the main pipe and again have to be connected after moving the entire assembly to another site.
This system has several disadvantages. It requires a large pumping capacity because of the resistance to the flow of slurry through the small diameter spigots. It is labor intensive since the branches have to be extended continuously. The branches are connected to and disconnected from the main pipe each time the system is moved to another site. The main drawback is the fact that the starter dyke which must be mechanically built to form an abutment for the succeeding deposition of the slurry must be quite high and wide requiring several weeks of work by mechanical earth movers such as bulldozers to place the required volume for the starter dyke. This represents a major portion of the cost of building or increasing the height of the retaining dyke. In addition, this system does not lend itself to general tailings disposal.
It is also known that for small smaller slurry flow requirements to provide a pipe with holes in the bottom suspended on wood racks. This method allows the deposition of the coarse portion of the tailings through the holes until they are successively obstructed. A length of this perforated pipe is installed perpendicular to the starter dyke.
This system has several disadvantages. It can only be used for general tailings disposal and is not efficient (in many cases inadequate) for dyke construction because it does not allow for a uniform distribution of the slurry material from the beginning to the end of the pipe, hence the deposition angle formed at each successive hole becomes flatter and flatter. It does not allow for control of the slurry composition.
OBJECTS OF THE INVENTION
It is therefore the general object of the present invention to overcome the above noted disadvantages in that the system of the invention requires starter dykes of minimum size, are less labor intensive in that no work is required to the distributor duct until it is displaced from one site to the other several days later and in that it requires less pumping capacity (20%) than conventional systems with branches fitted with spigots.
A second object of the present invention is the provision of a slurry distributor, which is less expensive to build and maintain than conventional distributors, and which is easily installed, advanced and removed onto and from a dyke building site.
A third object of the present invention is the provision of a slurry distributor, which can be used for general tailings disposal due to its capacity control the tailings composition and provide a uniform distribution of the slurry material along the entire length of the distributor.
SUMMARY OF THE INVENTION
This invention is directed to a slurry distributor which comprises a duct with an inlet end and an outer end, supports under said duct for supporting the same above ground in generally horizontal position, said duct having longitudinally spaced slurry discharge openings, said inlet end adapted to be connected to a supply of slurry under pressure whereby said slurry can be discharged from said duct directly unto the ground with the solid content of said slurry gradually forming dyke portions under and adjacent said duct along the length thereof and progressively obstructing said openings from said inlet end to said outer end. The duct is of generally rectangular cross-section and has a ceiling, a floor and side walls, said discharge openings made in said side walls, said opening arranged in pairs, the opening of each pair are aligned across of said duct and further including inverted V-shape baffles on said floor with the apices of said V-shape baffles meeting along the centre line of said floor and said baffles diverging in a direction opposite to said inlet end and ending at said openings.
Preferably, flat strips are secured at an angle to said side walls and to said floor and extending upstream from a single pair of registering discharge openings just upstream of the support.
Preferably, the top of the discharge openings on one side of said duct are at a lower level than the top of the discharge openings on the other side of said duct.
Preferably, the duct is made of two laterally spaced I-beam sections with the web of said I-beam forming said side walls and of top and bottom plates secured to the top and bottom flanges of said beam and forming with said flanges said ceiling and said floor of said duct.
Preferably, each discharge opening has along its sides vertically arranged guide ways located externally of said top and bottom flanges of said I-beam, and closure plates vertically guided in said guide ways.
Preferably, the duct is composed of two or more duct sections in end-to-end relation with connectors at each end of each section for connecting said sections.
Preferably, each duct section has a hook fixed to and upwardly protruding from its ceiling at the centre of gravity of said section to be bodily lifted and transported.
Preferably, said connectors include a pair of transversely registering ears upstanding from each end of said section, the ears at one end overlapping and removable attached to the ears at another end of an adjacent section whereby an additional section can be connected pin to an already installed section while inclined and then lowered to become in abutment with said already installed section with the adjacent ends of said two sections in abutment and in alignment.
Preferably, the openings on both sides of said duct have a sill at the same level above said floor but below the apices of said baffles and the openings on one side of the duct are higher than the openings on the other side of said duct.
Preferably, each of said supports is a box-like member with a downward extending skirt at the bottom of said support.
Preferably, a connector removable fitted to said inlet end of said duct, having a rectangular cross-section at one end to conform with the cross-sectional shape of said duct and having circular cross-section at the other end to be connected to a slurry supply cylindrical pipe.
Preferably, spaced apart sleeve members are secured to the underside of one of said duct sections spaced apart to receive the forks of a fork-truck and inclined with respect to the longitudinal axis of said duct section so that said duct section is inclined to the horizontal when lifted by the forks of said lift truck.
Preferably, there are hook means at the center of gravity of said duct section protruding upwardly from the ceiling of the same.
BRIEF DESCRIPTION OF THE DRAWINGS
In the annexed drawings, like reference characters indicate like elements throughout.
FIG. 1 is a side elevation of the distributor of the invention installed on a dyke building site;
FIG. 1 a is an enlarged view of a portion of one of the two duct sections;
FIG. 2 is a side elevation of two duct sections showing their coupling portions;
FIG. 3 is a top plan view of the view of the coupling portions shown in FIG. 2;
FIG. 4 is a cross-section of one duct section taken along line 4 — 4 of FIG. 6; and
FIG. 5 is a cross-section taken along line 5 — 5 of FIG. 4; and
FIG. 6 is a top plan section of one portion of the duct of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The distributor of the invention consists of a pipe or duct 2 of generally rectangular cross-section being for instance fifteen inches wide by twenty inches high. The duct is composed for instance of two duct sections, namely duct section 4 which may have seventy feet in length and duct section 6 which may have forty feet in length.
Each duct section is formed by two laterally spaced I-beams 8 as shown in FIG. 4, the top flanges 10 of each I-beam together with an intervening plate 12 welded thereto form the ceiling of the duct while the bottom flanges 14 and the bottom plate 16 welded thereto form the floor of the duct. The web 18 of I-beams 8 form the side walls of the duct. These side walls are provided with left and right discharge openings 20 and 22 respectively looking in the direction of flow of the slurry as shown by arrow A in FIGS. 1 and 6.
These discharge openings are arranged in pairs the openings of each pair aligned across the duct and each pair of openings are equally longitudinally spaced for a distance of, for instance, about ten feet along the length of duct 2 as shown in FIG. 1 . The number, placement and size of the openings is determined from the characteristics of the slurry material flowing in the duct. Each opening 20 and 22 has a sill 24 which is spaced above the floor 14 , 16 , the left discharge openings 20 have a top edge 26 which is at a lower level than the top edge 28 of right discharge openings 22 for a purpose which will be later described.
Each opening can be closed in a non-waterproof manner by means of a slide door 30 having a handle 31 . As shown in FIGS. 4 and 5, the slide door is guided for up and down movement by means of guideways formed on each side of the opening by an L-shaped vertical bar 32 and vertical angle irons 34 extended by a flat vertical bar 36 . The door is also guided by a flat horizontal bar 38 and comes to rest on an angle bar 39 .
The floor 14 , 16 of the duct 2 is provided with deflector baffles 40 formed of angle irons secured in upside down position and diverging in the direction of the slurry flow as shown at A in FIG. 6 . Baffles 40 are welded to flanges 14 and to centre filler plate 44 .
The apices 42 of the deflector baffles 40 are at a level slightly higher than the level of the sills 24 of the left and right discharge openings 20 , 22 as shown FIG. 4 . Deflector plates 46 are secured at an angle to the sidewalls and floor at each corner thereof and extend upstream from baffles 40 as clearly shown in FIG. 6. A floor hole 48 is made through the floor 14 , 16 just upstream from the baffles 40 and support 70 as shown in FIG. 6 .
The inlet end of the duct section 4 is connected to a connector tube 50 which has a cylindrical inner end 52 to be connected to a standard cylindrical pin for supplying slurry under pressure. The connector tube 50 has an outer end portion 54 of rectangular cross-section sized to form a but joint with the inner end of duct section 4 .
As shown FIGS. 2 and 3, the inner end of duct section 6 is provided with a pair of upstanding ears 56 supporting a cross-pin 58 adapted to engage the recesses 60 of ears 62 upstanding from duct section 4 when duct section 6 is upwardly inclined with respect to duct section 4 . Subsequent, lowering of duct section 6 brings the two adjacent ends of the sections 4 , 6 in abutment.
Duct section 4 (see FIG. 1) is provided with a hook 64 at its centre of gravity for handling the duct section 4 with a loader or the like. Also, straps 66 are disposed on each side of the hook 64 for raising and lowering the duct section by means of a fork truck or the like.
Similarly, as shown in FIG. 1 a, duct section 6 is provided at its centre of gravity with a hook 64 and a pair of upstanding straps 66 and it is further provided with fork receiving sleeves 68 protruding from the floor of the duct section and inclined with respect to the longitudinal axis of the section whereby said duct section can be manipulated by a fork truck while at a suitable inclination for hooking onto the previously laid duct section 4 by means of the connector assembly 56 to 62 .
The duct 2 is supported in generally horizontal position above ground G by means of a support 70 in the form of a box provided at its bottom with a skirt 72 to be inserted into the ground so as to stabilize a support 70 , which is positioned under the connector assembly 56 to 62 .
The slurry is normally composed of water and 20 to 60% solid material by weight of different size distribution. This material comes from the residues of the ore concentration operation and serves to build a dyke to eventually form a retaining pond for receiving the mine tailings. A starter dyke is first made using bulldozers or other mechanical equipment, this starter dyke of generally trapezoidal cross-section is made as small as possible in cross-section because of the heavy expenditure involved in the use of mechanical earth moving equipment as opposed to hydraulically depositing the material with the slurry distributor.
The duct 2 is laid along and a suitable distance determined by slurry characteristics from the starter dyke on the pond side thereof and is connected by the connector tube 50 to a slurry supply under pressure. The slurry is discharged from the discharge openings 20 , 22 closest to the connector tube and gradually forms a mound on each side of and underneath the duct 2 which becomes sufficiently high to obstruct these first upstream openings 20 , 22 . The slurry continues to the next downstream pair of discharge openings and is discharged at this site to form a mound. The process is continued until the deposited material successively obstructs all the openings.
The material is also directly discharged underneath the duct by the floor holes 48 . To prevent the discharge of granular material to build up to a level higher than duct 2 , the slide doors 30 are inserted to close the no-longer discharging openings 20 , 22 .
The support 72 becomes fully embedded into the deposited material.
One side of the discharge openings 20 is facing the starter dyke.
These openings have a lower height than the discharge opening 22 so that the finer portion of the slurry is trapped within the top of duct 2 and is not discharged from this side of the duct, only the coarser material being discharged so that the dyke can be built with as steep a slope as possible on the side of the starter dyke.
After the duct has become practically embedded in the granular material, it is moved to another site further along the length of the starter dyke to continue the building of the main dyke.
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The slurry distributor comprises two or more square pipe sections in end-to-end relation having an inlet at one end for connection to a slurry supply and provided with discharge openings equally spaced longitudinally thereof; on each side of the square pipe for discharge of the slurry, the openings being successively obstructed manually or by deposited solids from the slurry itself piling up on the original ground level. The distributor is used to control the slurry composition for dyke building and general tailings disposal consisting of mine tailings.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of the priority of U.S. Provisional Patent Application No. 60/459,990 filed Apr. 4, 2003, the entirety of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to structures and devices produced by techniques of nanotechnology.
More specifically, the invention relates to such structures and devices incorporating at least one element, essentially in one-dimensional form, and that is of nanometer dimensions in its width or diameter, and that preferably is produced by the so-called Vapor-Liquid-Solid (VLS) mechanism. For the purposes of this specification, such element will be termed a “nanowhisker”.
2. Brief Description of the Prior Art
Nanotechnology covers various fields, including that of nanoengineering, which may be regarded as the practice of engineering on the nanoscale. This may result in structures ranging in size from small devices of atomic dimensions, to much larger scale structures for example on the microscopic scale. Commonly, such structures include nanostructures. In certain contexts nanostructures are considered to be those having at least two dimensions not greater than about 100 nm, with some authors using the term to identify structures having at least two dimensions not greater than about 200 nm. Nevertheless, some procedures for fabricating such small structures are useful for structures having at least two dimensions somewhat greater, e.g., structures having at least two dimensions not greater than about 1 micrometer (μm). Ordinarily, layered structures or stock materials having one or more layers with a thickness less than 1 μm are not considered to be nanostructures. Thus, although the term “nanostructure” is more classically considered to refer to structures having at least two dimensions not greater than about 100 nm, in the following discussion, the term “nanostructure”, “nanowhisker”, or “nanoelement” is intended to include a structure having at least two dimensions not greater than about 1 μm.
Nanostructures include so-called one-dimensional nanoelements, essentially in one-dimensional form, that are of nanometer dimensions in their width or diameter, and that are commonly known as nanowhiskers, nanorods, nanowires, nanotubes, etc.
As regards nanowhiskers, the basic process of whisker formation on substrates, by the so-called VLS (vapor-liquid-solid) mechanism, is well known. A particle of a catalytic material, usually gold, for example, on a substrate is heated in the presence of certain gases to form a melt. A pillar forms under the melt, and the melt rises up on top of the pillar. The result is a whisker of a desired material with the solidified particle melt positioned on top. (See E.I Givargizov, Current Topics in Materials Science , Vol. 1, pages 79-145, North Holland Publishing Company, 1978.) The dimensions of such whiskers were in the micrometer range.
Although the growth of nanowhiskers catalyzed by the presence of a catalytic particle at the tip of the growing whisker has conventionally been referred to as the VLS (Vapor-Liquid-Solid) process, it has come to be recognized that the catalytic particle may not have to be in the liquid state to function as an effective catalyst for whisker growth. At least some evidence suggests that material for forming the whisker can reach the particle-whisker interface and contribute to the growing whisker even if the catalytic particle is at a temperature below its melting point and presumably in the solid state. Under such conditions, the growth material, e.g., atoms that are added to the tip of the whisker as it grows, may be able to diffuse through a the body of a solid catalytic particle or may even diffuse along the surface of the solid catalytic particle to the growing tip of the whisker at the growing temperature. Evidently, the overall effect is the same, i.e., elongation of the whisker catalyzed by the catalytic particle, whatever the exact mechanism may be under particular circumstances of temperature, catalytic particle composition, intended composition of the whisker, or other conditions relevant to whisker growth. For purposes of this application, the term “VLS process”, “VLS method”, or “VLS mechanism”, or equivalent terminology, is intended to include all such catalyzed procedures wherein nanowhisker growth is catalyzed by a particle, liquid or solid, in contact with the growing tip of the nanowhisker.
International Application Publication No. WO 01/84238 discloses in FIGS. 15 and 16 a method of forming nanowhiskers wherein nanometer sized particles from an aerosol are deposited on a substrate and these particles are used as seeds to create filaments or nanowhiskers.
For the purposes of this specification the term nanowhiskers is intended to mean “one-dimensional” nanoelements with a width or diameter (or, generally, a cross-dimension) of nanometer size, the elements having been formed by the so-called VLS mechanism. Nanowhiskers are also referred to in the art as “nanowires” or, in context, simply as “wires”, and such terminology, as used in this application, is equivalent to the term “nanowhiskers”.
Several experimental studies on the growth of nanowhiskers have been made, including those reported by Hiruma et al. They grew III-V nano-whiskers on III-V substrates in a metal organic chemical vapor deposition (MOCVD) growth system. (See K. Hiruma, et al., J. Appl. Phys. 74, page 3162 (1993); K. Hiruma, et al., J. Appl. Phys. 77, page 447 (1995); K. Hiruma, et al., IEICE Trans. Electron . E77C, page 1420 (1994); K. Hiruma, et al., J. Crystal Growth 163, pages 226-231 (1996)).
Hiruma et al. have made pn junctions within nanowhiskers by doping GaAs whiskers with Si using Si 2 H 6 , during the growth process, and switching the dopant to an opposite conductivity type (carbon) during growth: K. Hiruma et al., J. Appl. Phys. 77(2), 15 Jan. 1995 p.447, see pages 459-461; and K. Hiruma et al J. Appl. Phys. 75(8) 4220 (1994). In general, there are problems in that the definition of the junction within the nanowire is not good enough for electrical components, and in that the presence of dopant ions within the crystal creates crystal imperfections and reduces carrier mobility.
In another approach by Lieber et al, WO-A-03/005450, nanowires were produced, different wires being doped with opposite conductivity type dopants, and two wires of opposite conductivity type were physically crossed, one on top of the other, so that a pn junction was formed at their point of contact. A difficulty with this approach is the extra step required of physically positioning the nanowires.
In planar semiconductor processing, various doping techniques are known. One technique that is valuable with heterojunctions is known as modulation doping. In this technique, carriers from a doped layer of, e.g., AlGaAs, diffuse across an interface with an undoped material, e.g., GaAs, and form a very thin layer of carriers of very high mobility, within a potential well, next to the interface—see for example FIG. 1 of WO 02/19436.
U.S. Pat. No. 5,362,972 discloses an FET wherein the current flowpath between source and drain is composed of GaAs nanowhiskers. The nanowhiskers are surrounded by n-doped AlGaAs, to create by modulation doping a one-dimensional electronic gas within each nanowhisker.
WO 02/020820 discloses a modulation doping technique in Coaxial Heterostructure Nanowires, wherein dopants in an outer coaxial layer donate free carriers to an inner nanowire.
In other techniques, doping of a semiconductor region in a planar semiconductor device occurs by diffusion of ions from an adjacent region of polymer; see Guk et al., Semiconductors Vol. 33(3), pp. 265-275, March 1999.
In co-pending U.S. patent application Ser. No. 10/613,071, filed on Jul. 7, 2003, in the names of Samuelson and Ohlsson, the contents of which are incorporated herein by reference, a process was disclosed for producing nanowhiskers, and structures were disclosed incorporating nanowhiskers.
SUMMARY OF THE INVENTION
It is an object of the invention to provide new and improved nano-engineered structures incorporating nanowhiskers and other one-dimensional nanoelements, the nanoelements having improved conductivity characteristics.
It is a further object of the invention to provide new and improved nano-engineered structures incorporating nanowhiskers and other one-dimensional nanoelements, wherein the nanoelements contain improved pn junctions.
In at least a preferred embodiment of the invention, nanowhiskers or other one-dimensional nanoelements are grown as pure crystals without doping. The nanowhisker is then enclosed in an enclosure comprising a surrounding layer or matrix of a further different material that will usually be a semiconductor material. Dopant ions are incorporated into this further material, by an appropriate process during or after its deposition. Carriers liberated in the further material transfer into the nanowhisker. The band structures of the nanoelement and the further material ensure that it is energetically favorable for the carriers to diffuse into the nanoelement; this is effectively by the process known as modulation doping wherein a potential well is defined within the nanowhisker. Thus effectively the nanowhisker is doped with carriers, but that these are of high mobility, since the absence of dopant ions within the nanowhisker ensures that the crystalline structure is not deformed.
The preferred embodiment provides a method of producing a one-dimensional nanoelement of desired conductivity, the method comprising the steps of (1) forming a one-dimensional nanoelement of a first material, (2) surrounding the nanoelement with a second material, different from that of the nanoelement, the second material containing dopant material whereby charge carriers from the dopant material diffuse into the nanowhisker to create said desired conductivity. More specifically, the method comprises the steps of (1) forming by the VLS method a nanowhisker on a substrate, the nanowhisker including a first semiconducting material, and (2) forming a coaxial layer around the nanowhisker of a second semiconducting material, and (3) incorporating dopant material into the coaxial layer whereby charge carriers from the dopant material diffuse into the nanowhisker to create said desired conductivity.
The invention provides a means of creating a pn junction within a one-dimensional nanoelement by modulation doping.
Specifically the invention provides a nanoengineered structure including a one-dimensional nanoelement of a first semiconducting material having a first bandgap, an enclosure comprising at least one second material having a second bandgap enclosing said nanoelement along at least part of its length, and said second material being doped to provide opposite conductivity type charge carriers in respective first and second regions along the length of the of the nanowhisker, whereby to create by transfer of charge carriers into said nanoelement, corresponding first and second regions of opposite conductivity type charge carriers with a pn junction therebetween in said nanoelement, and wherein the bandgaps are such that it is energetically favorable for the charge carriers to remain in said nanoelement.
The enclosure for the nanoelement may be a coaxial jacket. In one preferred form a thin nanowhisker of GaAs is grown, then the growth conditions are changed from those appropriate for catalytic growth to those appropriate for bulk growth, so that a coaxial jacket is formed around the sides of the nanowhisker. The material may be AlGaAs. It is necessary to dope the lower part of the AlGaAs jacket with one conductivity type dopant material, and the upper parts of the coaxial jacket with opposite conductivity dopant ions. One exemplary technique for achieving this is to embed the coaxial jacket within a polymer matrix comprising upper and lower layers as, for example, spin on glass or polymer substances. The lower layer has one conductivity type dopant material, and the upper layer has the opposite conductivity type dopant material. Rapid thermal annealing causes diffusion of the dopant material into the coaxial jacket. The thermal annealing step is stopped before appreciable diffusion into the one-dimensional nanoelement. The presence of the dopant ions within the coaxial jacket creates modulation doping within the nanowhisker, and a pn junction between the two regions of opposite conductivity type material. The space charge within each region is maintained within the nanoelement, and the depletion region of the pn junction may be sharp or as diffuse as desired (typically within the range 50 nm to 1 μm). The diameter of the nanowhisker is preferably small, about 20 nm. The coaxial jacket may be as small as 10 nm thick, but it may in other cases be preferable to have a jacket that is 200 nm thick or one that even fills the volume between the nanowires completely in an array of nanowires.
The materials of the nanowire and jacket may be GaAs and AlGaAs, for example. Other material combinations could be InAs in the core section and AlSb in the surrounding material or a germanium core and a silicon jacket.
In a modification, the coaxial jacket is doped in one conductivity type during its formation. A layer of spin-on glass is then formed partway along the length of the nanowire, containing opposite type conductivity ions, that are sufficiently concentrated to reverse the conductivity type in the lower part of the coaxial jacket. In a further modification, the coaxial jacket is grown in an undoped condition, and a layer of spin-on glass is then formed partway along the length of the nanowire, containing one type conductivity ions. The structure is then exposed to a gas containing opposite type conductivity ions that diffuse into the upper part of the coaxial jacket, where they create a region of opposite conductivity type. The ions in the gas also diffuse into the layer of spin on glass, but not in a sufficient concentration to overcome the existing concentration of the one type conductivity. A pn junction is thereby formed in the nanowire.
In an alternative form, the one-dimensional nanoelement is encapsulated within an enclosure formed by first and second layers of polymer material or spin on glass, each layer having opposite conductivity dopant material. Direct charge transfer of the carriers from the polymer matrix creates modulation doping within the nanowhisker, and two separate regions of oppositely signed charge carriers with a pn junction between them.
In a further alternative form of the invention the doping is so heavy as to create degenerate doping within the nanoelement, that is to say the Fermi level exists, in one region, in the conduction band, and in the other region, in the valence band. In this state, the nanoelement comprises a tunnel diode or Esaki diode wherein in known manner, forward biasing of the junction creates a negative resistance caused by tunnelling between the valence and the conduction bands.
In a further aspect, a nanowhisker or other one-dimensional nanoelement is surrounded by a material containing dopant ions. For example the surrounding material may be a polymer material. By a process, for example a subsequent step of rapid thermal annealing, the dopant ions in the matrix material are permitted themselves to diffuse into the nanowhisker, to create a desired conductivity. This provides advantages over a direct doping into the nanoelement, by providing an extra degree of control over the doping process, and permitting the diffusion of certain dopants into the nanoelement that would not be possible by a more direct process. Although a polymer material is preferred, which is evaporated or spun onto a substrate so as to surround the nanowhisker, other materials may be employed, such as for example semiconductor material or dielectric material grown onto the substrate. The dopant material may be incorporated in the surrounding material before application to the substrate, during the application to the substrate, or as a subsequent step after the surrounding material is formed on the substrate.
Specifically, the invention provides a method of forming a one-dimensional nanoelement of a desired conductivity, comprising:
(a) forming a one-dimensional nanoelement on a substrate, the nanoelement being formed of a first material; (b) forming at least a first layer of a further material on the substrate and surrounding, at least partially, the nanoelement, the further material having a first conductivity type dopant material therein, and (c) processing the further material so that said dopant material diffuses into the nanoelement, whereby to create a desired conductivity therein.
Additionally, the invention provides a nanoengineered structure, comprising a one-dimensional nanoelement, of a first material, disposed on a substrate, and at least a first layer of material formed on the substrate and surrounding, at least partially, the nanoelement, the first layer having a first conductivity type dopant material therein, said first conductivity type dopant material having diffused into the nanoelement, whereby to create a desired conductivity within the nanoelement.
In a further aspect, a pn junction is created within a one-dimensional nanoelement, preferably a nanowhisker. A nanowhisker is grown on a substrate, and embedded in a surrounding material. The material consists of first and second layers, formed on the substrate, one on top of the other, for example as polymer layers evaporated or spun onto the substrate. Alternatively the layers may be of some other material, for example dielectric material or semiconducting material grown on the substrate. The first layer extends partway up the nanowhisker, and has a first dopant material incorporated within it or subsequently injected, providing charge carriers of a first type. The second layer extends towards the top of the nanowhisker, and has a second dopant material contained within it or subsequently injected into it, providing charge carriers of an opposite conductivity type. The surrounding material is treated, as for example by rapid thermal annealing, so that the dopant ions themselves diffuse into the respective first and second regions of the nanoelement, to create an effective pn junction within the nanowhisker. In this case, the surrounding layers may be commercially available polymer layers evaporated or spun onto the substrate. The dopant materials are incorporated into the polymer materials before, during, or after the application of the polymer materials to the substrate.
In either case, the effective pn junction can be made as sharp as desired, approaching that of a few nanometers. More than one pn junction may be created by employing multiple layers, each layer having appropriate dopant material.
Specifically the invention provides a nanoengineered structure including a one-dimensional nanoelement with at least one pn junction therein, comprising a nanowhisker upstanding from a substrate, and a first layer of a material formed on the substrate and surrounding and extending partway up the nanowhisker, the first layer having a first conductivity type dopant material therein, and a second layer of material formed on top of the first layer and surrounding and extending towards the top of the nanowhisker, and having a second conductivity type dopant material therein, whereby to create by diffusion from said first and second layers into respective first and second regions of the nanowhisker, a pn junction within the nanowhisker between the first and second regions.
The invention also provides a method of forming a one-dimensional nanoelement with a pn junction therein, comprising:
(a) forming a nanowhisker upstanding from a substrate, (b) forming a first layer of material on the substrate and surrounding and extending partway up the nanowhisker, the first layer having a first conductivity type dopant material therein, and (c) forming a second layer of material on top of the first layer and surrounding and extending towards the top of the nanowhisker, and having a second conductivity type dopant material therein, so that diffusion from the first and second layers into respective first and second regions of the nanowhisker creates a pn junction within the nanowhisker between the first and second regions.
In a fifth aspect, the invention recognises that there are problems in chemical doping of dopant ions in a nanowhisker of III-V semiconductor material, since for most III-V semiconductors, solid solubility at room temperature is limited, and during cooling out-diffusion is fast with these nanodimensions. Thus the amount of doping within the nanowhisker may be difficult to accurately predetermine. The invention recognises that the interface between a nanoelement and a surrounding medium, or a heterojunction interface within a nanoelement, may have a stronger and more significant role than hitherto realised in determining the electrical characteristics of the nanoelement.
It is known that localised surface “trap” states exist at the surfaces of bulk semiconductors; this is exhibited for example in Schottky diodes. This creates what is known as Fermi Level Pinning, where the surface trap states determine the relative levels of the conduction and valence bands in the junction materials. See, e.g., “Defective Heterojunction Models”, Freeouf J L, Woodall J M,: IBM Corp,: Surface Science, 1986, V 168, N1-3, P 518-530.
The invention recognises that for a one-dimensional nanoelement, where there may be a wide range of possibilities to combine III-V semiconductors in spite of lattice mismatch, Fermi Level Pinning is a constructive way to make pn-junctions by choosing semiconductor alloy composition to determine carrier type. In such devices the band gap can be engineered and the carrier type can be controlled to make new types of semiconductor devices. When a semiconductor crystal ends abruptly at an interface, and “band bending” tends to occur to equalize the Fermi Levels on the two sides of the interface, Fermi Level Pinning, arising from the existence of surface trap states, counteracts this effect to reduce the amount of charge transfer across the interface.
The invention further provides a one-dimensional nanoelement including a first segment of a first semiconductor crystalline material, and a second segment of a second semiconductor crystalline material different from that of the first, and with a heterojunction therebetween, whereby the first and second materials are selected such that charge carriers of opposite conductivity type are provided at the opposite sides of the heterojunction interface so as to create a pn junction with predetermined characteristics, which characteristics are at least partially determined by Fermi level pinning.
The invention also provides a method of forming a pn junction comprising:
a. forming a one dimensional nanoelement having a first segment of a first crystalline material, and a second segment of a second crystalline material different from that of the first, with a heterojunction therebetween, b. the first and second materials being selected so as to provide charge carriers of opposite conductivity type at the heterojunction so as to create a pn junction with predetermined characteristics, which characteristics are at least partially determined by Fermi level pinning.
In accordance with the invention, the charge carriers can be provided by the intrinsic nature of the first and second materials. For III-V materials, stoichiometric compositions of ternary or quaternary materials can be chosen for desired conductivity characteristics.
It has been found that the present invention is particularly applicable to III-V compounds epitaxially grown (CBE or MOCVD, or MOVPE), under group III rich conditions. Under these conditions, the outermost atomic surface layers may have excess Ga or In ions and these create defect states, as further described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will now be described with reference to the accompanying drawings, wherein:
FIG. 1 is a schematic of the CBE apparatus used for making the described embodiments.
FIG. 2 is a cross-sectional schematic view showing a step in the formation of the first embodiment of the invention, with an accompanying energy band diagram.
FIG. 3A shows a cross-section of a nanowhisker prepared by the VLS method.
FIG. 3B shows a cross-section of a nanowhisker having an enclosure or jacket according to the invention.
FIG. 3C shows an array of such clad nanowhiskers extending from a (111) surface.
FIG. 3D shows an enlarged view of a nanowhisker having been separated from the surface.
FIG. 3E is a view of the cross-section of the clad nanowhisker showing a hexagonal structure that is characteristic of nanowhiskers growing in a <111> direction.
FIG. 3F is a luminescence curve showing characteristic peaks at approximately 1.5 and 1.8 eV, which represent GaAs and AlGaAs materials respectively.
FIG. 4 is a cross-sectional view of a second embodiment of the invention.
FIG. 5 is a cross-sectional schematic view of a third embodiment of the invention.
FIG. 6 is a cross-sectional schematic view of a fourth embodiment of the invention.
FIG. 7 is a cross-sectional schematic view of a fifth embodiment of the invention.
FIG. 8 is a cross-sectional schematic view of a sixth embodiment of the invention.
FIG. 9 is a graph showing the energy levels of the bands and surface states of a number of semiconductor materials.
FIG. 10 is a schematic energy level diagram for the doped nanowhiskers of FIG. 7 and FIG. 8 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments to be described are all formed with nanowhiskers, preferably according to the Chemical Beam Epitaxy method (CBE) described in copending U.S. patent application Ser. No. 10/613,071 filed Jul. 7, 2003, the contents of which are herein incorporated by reference.
As indicated above, in the following detailed description of the invention, the term “nanoengineered structures” signifies a structure that includes structures, e.g., elements, parts, or the like, having dimensions as defined above, i.e., structures having at least two dimensions less than about 1 micrometer. Such structures are referred to herein as “nanoelements” or nanostructures, and/or, because of their generally elongated shape, as “nanowhiskers” or “nanowires”.
Chemical Beam Epitaxy (CBE) combines a beam epitaxial technique like Molecular Beam Epitaxy (MBE) and the use of chemical sources similar to Metal Organic Chemical Vapor Deposition (MOCVD). In MOCVD or related laser ablation techniques, the pressure inside the reactor is usually greater than 10 mbar and the gaseous reactants are viscous, which means that they have a relatively high resistance to flow. The chemicals reach the substrate surface by diffusion. CBE reduces the pressure to less than 10 −4 mbar and the mean free path of the diffusants then becomes longer than the distance between the source inlet and the substrate. The transport becomes collision free and occurs in the form of a molecular beam. The exclusion of the gas diffusion in the CBE system means a fast response in the flow at the substrate surface and this makes it possible to grow atomically abrupt interfaces.
The CBE apparatus shown in FIG. 1 consists of a UHV growth chamber 100 where the sample 102 is mounted on a metal sample holder 104 connected to a heater 106 . Around the chamber there is a ring 108 filled with liquid nitrogen that is called the cryoshroud. The cryoshroud pumps away species that don't impinge or that desorb from the substrate surface. It prevents contamination of the growing surface layer and reduces the memory effect. Vacuum pumps 110 are provided.
The sources 112 for CBE are in liquid phase and they are contained in bottles which have an overpressure compared to the chamber. The sources are usually as follows: TMGa, TEGa, TMIn, TBAs, and TBP. The bottles are stored in constant-temperature baths and by controlling the temperature of the liquid source, the partial pressure of the vapor above the liquid is regulated. The vapor is then fed into the chamber through a pipe complex 114 to, in the end of the pipe just before the growth chamber, a source injector 116 . The source injector is responsible for injection of the gas sources into the growth chamber 100 , and for generation of a molecular beam with stable and uniform intensity. The III-material, from the metal organic compounds TMIn (trimethylindium), TMGa (trimethylgallium) or TEGa (triethylgallium), will be injected by low temperature injectors to avoid condensation of the growth species. They will decompose at the substrate surface. The V-material is provided by the metal-organic compounds, TBAs (tertiarybutylarsine) or TBP (tertiarybutylphosphine). As opposed to the decomposition of the III-material, the V-material will be decomposed before injection into the growth chamber 100 , at high temperatures, in the injectors 116 . Those injectors 116 are called cracking cells and the temperatures are kept around 900° C. The source beam impinges directly on the heated substrate surface. Either the molecule gets enough thermal energy from the surface substrate to dissociate in all its three alkyl radicals, leaving the elemental group III atom on the surface, or the molecule get desorbed in an undissociated or partially dissociated shape. Which of these processes dominates depends on the temperature of the substrate and the arrival rate of the molecules to the surface. At higher temperatures, the growth rate will be limited by the supply and at lower temperatures it will be limited by the alkyl desorption that will block sites.
This Chemical Beam Epitaxy method permits formation of heterojunctions within a nanowhisker, which are abrupt, in the sense there is a rapid transition from one material to another over a few atomic layers.
Referring now to FIG. 2 , a first embodiment of the invention is formed by positioning a gold aerosol particle 2 on a III-V substrate 4 , e.g., a gallium arsenide substrate. With appropriate conditions of temperature and pressure a nanowhisker of indium arsenide is grown by injecting organic materials TMIn and TBAs in a conventional VLS procedure, e.g., in a chemical beam epitaxial method, using the apparatus described above, or by a metal organic vapor phase epitaxy (MOVPE), or the like. Indium and arsenide ions are absorbed in the gold particle 2 and supersaturation conditions create a solid pillar 6 of indium arsenide.
Once the indium arsenide whisker has been grown, different materials TEGa and TBP are used to create a coaxial jacket or surrounding layer 8 of GaP around the nanowhisker 6 . Layer 8 may be created by CBE; using the apparatus of FIG. 1 , wherein the conditions of temperature ( 106 ) and/or pressure ( 112 ) are changed to inhibit growth by the VLS mechanism, and instead to support bulk growth. Alternatively the gold melt particle 2 can be removed mechanically, so that subsequent growth of GaP will occur in bulk form
The resulting energy level bandgap diagram is shown with an energy gap of 2.3EV separating the conduction bands for gallium phosphide, whereas there is a bandgap of 0.3EV for the central indium arsenide whisker.
The jacket or shell material (GaP in this case) may then be doped, e.g., via the vapor phase, resulting in a sheath at the periphery of the GaP jacket which will contain donor dopants such as tellurium.
As an alternative to tellurium, any donor dopant materials that are commonly used for GaP may be used, see for example CRC The Handbook of Chemistry and Physics, Semiconductor Properties, e.g., Si, Sn, Te, Se, S, or the like. Alternatively, if an acceptor-doped jacket or shell is desired, appropriate acceptor materials, e.g., Zn, Fe, Mg, Be, Cd, or the like, can be incorporated.
As an alternative to InAs/GaP, any other combination of materials may be used, subject to the bandgaps providing energetically favorable conditions—the band gap of the surrounding layer should be wider than that of the nanowhisker; thus for a whisker of InAs, covering materials of GaAs, GaP or InP may be employed—see for example CRC The Handbook of Chemistry and Physics, Semiconductor Properties.
The effect of doping with tellurium ions is to liberate charge carrier electrons within gallium phosphide layer 8 . These electrons preferentially transfer into the central nanowhisker, where the energy states (conduction band/valence band levels) determine that the electrons are in energetically favorable condition. The theory is essentially that of modulation doping that is a technique employed in planar technology as described in WO 02/1438.
This therefore creates a nanowhisker with a desired electrical conductivity. The nanowhisker also has a high mobility because there are no dopant ions within the crystal lattice deforming the lattice structure.
Referring now to FIGS. 3A to 3F there is shown a specific example of the first embodiment of the invention. Nanowhiskers 6 of gallium arsenide were grown from gold catalytic particles by an epitaxial process from a GaAs substrate having a (111) surface. The growth conditions were then changed by altering the temperature, and modifying the gaseous pressure of the As-containing gas, so as to grow epitaxially, by bulk growth rather than catalytic growth, material of AlGaAs along the side of the GaAs nanowhiskers. The result as shown in FIGS. 3B and 3C are cylinders, in the form of a candle, with an inner core 6 of a GaAs 20 nanometers in diameter, and an outer cladding 8 of AlGaAs between 100 and 5000 nanometers in diameter.
FIG. 3C shows an array of such clad nanowhiskers extending from a (111) surface.
FIG. 3D shows an enlarged view of a nanowhisker having been separated from the surface.
FIG. 3E is a view of the cross-section of the clad nanowhisker showing a hexagonal structure that is characteristic of nanowhiskers growing in a <111> direction.
FIG. 3F is a luminescence curve showing characteristic peaks at approximately 1.5 and 1.8 eV, which represent GaAs and AlGaAs materials respectively. An intermediate hump is thought to be caused by spatially indirect transitions.
Referring now to FIG. 4 there is shown a second embodiment of the invention. Similar parts to those of FIG. 2 are identified by the same reference numeral. A structure is produced comprising an inner nanowhisker of GaAs material 6 , produced from a catalytic particle 2 . The whisker is surrounded by a coaxial jacket 8 of AlGaAs. Then, first and second layers 20 , 22 are provided, being of polymer or glass material spun on to the surface of substrate 4 . Layer 20 contains n type dopant ions 24 , and layer 22 contains p type dopant ions 26 . A rapid thermal annealing step ensures that dopant ions 24 , 26 migrate into corresponding regions 28 , 30 of coaxial jackets 8 . The annealing step is controlled such that there is no appreciable diffusion into the nanowhisker 6 .
The result is that the dopant ions within regions 28 , 30 create corresponding regions 32 , 34 within nanowhisker 6 by modulation doping of opposite conductivity type. These regions that are stable space charge regions create a region 36 depleted of free carriers resembling the depletion region of a pn junction between semiconductor materials of opposite conductivity type.
The level of dopant concentration within regions 28 , 30 may be such that highly degenerative doping is produced, with correspondingly heavy modulation doping of the segments 32 , 34 of the nanowhisker. Such heavy modulation doping may create a condition analogous to that existing in an Esaki or tunnel diode, with corresponding tunnelling between the regions and an associated negative resistance effect.
Referring now to FIG. 5 , there is shown a third embodiment of the invention, wherein similar parts to those of FIG. 2 are denoted by the same reference numeral. Thus an indium arsenide nanowhisker 6 is grown on a gallium arsenide substrate 4 by chemical beam epitaxy employing a gold catalytic particle 2 .
After formation of the nanowhisker, a first layer 50 of polymer material is evaporated (preferred) or spun onto the substrate 4 . There is commercially available a wide range of dielectric materials formed of carbon or silicon based polymers, some of which are doped and have defined electrical conductivity characteristics. The polymer material has contained within it a desired concentration of dopant ions of a desired type. As may be seen, layer 50 extends towards the top of the nanowhisker. The depth of layer 50 can be determined very accurately with evaporation of polymer.
The entire structure is then subject to rapid thermal annealing. This permits the dopant ions in the polymer material layer 50 to diffuse into the nanowhisker regions 54 , to provide a controlled doping of the regions 54 . The temperature of the annealing step depends on the materials employed.
There is thus provided a nanowhisker with a desired degree of conductivity, the method of doping providing a high degree of control over the conductivity.
Referring now to FIG. 6 , there is shown a fourth embodiment of the invention, wherein similar parts to those of FIG. 2 are denoted by the same reference numeral. Thus an indium arsenide nanowhisker 6 is grown on a gallium arsenide substrate 4 by chemical beam epitaxy employing a gold catalytic particle 2 .
After formation of the nanowhisker, a first layer 60 of polymer material is evaporated (preferred) or spun onto the substrate 4 . There is commercially available a wide range of dielectric materials formed of carbon or silicon based polymers, some of which are doped and have defined electrical conductivity characteristics. The polymer material has contained within it a desired concentration of dopant ions of a desired type. As may be seen, layer 60 extends roughly halfway along the length of the nanowhisker. Thus, for a nanowhisker that is 2 micrometers long, the depth of layer 60 is 1 micrometer. The depth can be determined very accurately with evaporation of the polymer.
A second layer 62 of polymer material of the same type as the first but having a dopant material of opposite conductivity type is evaporated on to layer 60 and extends up to the top of the nanowhisker, to a height approximately the same as the gold particle 2 .
The entire structure is then subject to rapid thermal annealing. This permits the dopant ions in the polymer material layer 60 to diffuse into the adjacent nanowhisker region 64 , to provide a controlled doping of the region 64 . Further, the dopant ions in the polymer material layer 62 diffuse into the adjacent nanowhisker region 66 , to provide a controlled doping of the region 66 . The temperature of the annealing step depends on the materials employed.
Thus, region 64 of whisker 6 may contain for example negative charge carriers, whereas positive charge carriers from layer 62 are contained in region 66 of whisker 6 . This effectively creates a pn junction 68 between the two regions 64 , 66 .
The junction 68 may be sharply defined within the nanowhisker. For types of dopant materials, any of the commonly used materials may be used. See, e.g., CRC The Handbook of Chemistry and Physics, Semiconductor Properties.
Three or more layers of polymer may be deposited, each with appropriate dopant materials. This permits the formation of multiple pn junctions within the whisker.
Referring now to FIGS. 7 to 10 , there is shown fifth and sixth embodiments of the invention. In FIG. 7 a nanowhisker is shown upstanding from a substrate 70 , having a gold catalytic particle 72 at its top, and being composed of a material 74 , preferably a III-V compound such as GaAs, InAs, InP. The nanowhisker has its sides defined by (110) surfaces. The whisker is formed by the CBE method as described above. The nanowhisker is embedded in a surrounding layer 76 of a second material different from that of the first, but preferably also a III-V compound such as GaAs, InAs, InP. The material of region 74 may be gallium arsenide, whereas material region 76 may be indium arsenide. Material region 76 is also grown by CBE, with conditions of temperature and/or pressure adjusted to support bulk growth, rather than VLS growth.
Preferably, nanowhiskers of III-V compounds are grown under group-III rich growth conditions (In, Ga, Al, B) that is for example an excess of TEGa is used for CBE growth of whiskers containing Ga. This ensures that the outermost surface of the nanowhisker has a slight excess of the group III compound Ga, and is therefore intrinsically p-type. The embedding layer 76 is InP, which embedding layer also grown under group III rich conditions to ensure a slight excess of In. The outermost surfaces of the nanowhisker are (110) surfaces.
Thus, a pn-junction results by combining GaAs (p-type intrinsically) with InP (n-type intrinsically). Another example would be InAs, which is almost degenerately n-type intrinsically.
By way of explanation, it is well understood that, at the free surface of a semiconductor, surface relaxation and surface reconstruction may take place, to minimise free energy, in particular from charge imbalance. Surface reconstruction may involve rearrangement of the crystal lattice; this is particularly so for GaAs (111) surfaces. Further, surface trap states are created in the bulk band gap, and this strongly modifies the charge balance at the surface. This creates, in known manner, a deformation of the band structure near the surface. The band edges bend upwards so that the surface states cross the Fermi level and start to empty, decreasing the surface charge density. The region over which the bands are bent is termed the depletion region because it has been depleted of mobile carriers. If the surface state density at a semiconductor surface has a high value, the band bending will saturate. At this point the Fermi level is said to be pinned by the surface states.
Since in this embodiment, the nanowhisker is grown under group III rich conditions, the surface reconstruction creates, from these excess group III atoms, deep-level like defects, the energy position of which are related to the vacuum level, not to the band edges of the semiconductors (this corresponds to the situation for other deep level impurities in bulk III-V semiconductors).
Referring to FIG. 9 , this shows the band gaps for a range of III-V compounds grown under group III rich conditions, with surface trap states indicated by crosses occurring in the band gaps. It will be noted that for all the compounds, the energy levels for the trap states are roughly equal, relative to vacuum level. This implies that pn junctions can simply be created by Fermi Level pinning at an interface between two such materials.
Thus, the situation arises that the surface of a GaAs whisker is p-type, whereas the surface of an InP whisker is n-type. Further the surface of layer 76 surrounding and embedding the whisker will have a conductivity governed by similar considerations. Thus Fermi Level pinning will ensure that the surface of a surrounding InP layer is n-type; hence if the whisker is GaAs, a pn junction is created by the Fermi Level Pinning effects. The situation is shown in FIG. 10 , where the relative levels of the band gaps of GaAs and InP are determined by Fermi Level Pinning, arising from the surface trap states.
In an alternative, where the whisker and surrounding layer are grown by MOVPE, then the MOVPE process has to be tuned to give Group III rich conditions of growth.
In a further embodiment as shown in FIG. 8 , a heterojunction 88 within a nanowhisker 82 between an indium phosphide segment 84 and a gallium arsenide segment 86 assumes the character of a pn junction along a (001) or (100) crystal plane. This is because GaAs is intrinsically p-type whereas indium phosphide is intrinsically n-type. The side facets of the whisker are (111) planes that have many surface states which establish a surface Fermi level (pinned Fermi level) which is characteristic of p-type or n-type semiconductor material, respectively. For nanowhiskers of a diameter of about 100 nm or less, there is insufficient diametral distance to permit band bending in the interior of the whisker to a level characteristic of the bulk semiconductor. Consequently, the conductivity type of each of the segments 82 , 84 is determined by the Fermi-level pinning produced by the surface states on the side facets of each segment. Accordingly, the heterojunction 88 becomes a pn junction between the indium phosphide segment 84 and the gallium arsenide segment 86 of the nanowhisker.
The skilled practitioner will, of course, recognize that the above-described embodiments are illustrative of the present invention and not limiting.
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Nano-engineered structures are disclosed, incorporating nanowhiskers of high mobility conductivity and incorporating pn junctions. In one embodiment, a nanowhisker of a first semiconducting material has a first band gap, and an enclosure comprising at least one second material with a second band gap encloses said nanoelement along at least part of its length, the second material being doped to provide opposite conductivity type charge carriers in respective first and second regions along the length of the of the nanowhisker, whereby to create in the nanowhisker by transfer of charge carriers into the nanowhisker, corresponding first and second regions of opposite conductivity type charge carriers with a region depleted of free carriers therebetween. The doping of the enclosure material may be degenerate so as to create within the nanowhisker adjacent segments having very heavy modulation doping of opposite conductivity type analogous to the heavily doped regions of an Esaki diode. In another embodiment, a nanowhisker is surrounded by polymer material containing dopant material. A step of rapid thermal annealing causes the dopant material to diffuse into the nanowhisker. In a further embodiment, a nanowhisker has a heterojunction between two different intrinsic materials, and Fermi level pinning creates a pn junction at the interface without doping.
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BACKGROUND OF THE INVENTION
This application relates to compounds, their pharmaceutically acceptable salts, and pharmaceutical preparations made therefrom, having utility in the treatment of hypertension in subjects suffering therefrom.
SUMMARY OF THE INVENTION
Broadly stated, the present invention comprises compounds of the formula (1) ##STR2## and their pharmaceutically acceptable acid addition, alkali metal, and alkaline earth metal salts, wherein
Q is Y 1 --C(O)--C*H(R 1 )--NH--, --NH 2 , R 1 --C(O)--S--(C*H(R 1 )) 0-1 --, or HS--(C*H(R 1 )) 0-1 --;
Y 1 and Y 2 are independently --OH, --OR, or --NR 1 R 2 ;
one of x and y is 1 and the other is 0;
R, R 1 , R 2 , R 4 and R 5 are independently hydrogen, alkyl having 1 to 8 carbon atoms, aryl having up to 12 carbon atoms, aryl-alkyl wherein the aryl moiety has up to 10carbon atoms and the alkyl moiety has 1 to 6 carbon atoms, cycloalkyl having 3 to 10 carbon atoms, fused cycloalkylaryl having 8 to 12 carbon atoms, heterocyclic, or an amino-substituted alkyl group having 1 to 6 carbon atoms;
A, B and E are independently H, halogen, --OH, --OR, --CF 3 , --NR 1 R 2 , --C(O)Y 1 , --SO 2 R, or --SO 2 NR 1 R 2 ; provided that at least two of A, B and E are not H;
X 1 is --(CH 2 ) a --, --(CH 2 ) b S(CH 2 ) c --, --(CH 2 ) b C(O)(CH 2 ) c --, or --(CH 2 ) b CH(R 3 )(CH 2 ) c --;
X 2 is --(CH 2 ) d --, --(CH 2 ) e S(CH 2 ) f --, --(CH 2 ) e C(O)(CH 2 ) f --, or --(CH 2 ) e CH(R 3 )(CH 2 ) f --;
provided that a and d are each 0-4; b c, e, and f are each 0-3; (a+d) is 2-4; (a+e+f) is 1-3; (b+c+d) is 1-3; and (b+c+e+f) is 0-2; and
R 3 is --OH, phenyl, or an alkyl or alkoxy group having up to 6 carbon atoms;
wherein the alkyl, cycloalkyl, aryl, and fused aryl-cycloalkyl groups may carry substituents selected from the group consisting of alkoxy with 1 to 6 carbon atoms, alkyl with 1 to 6 carbon atoms, --CF 3 , --OH, --SH, halogen, --NO 2 , and --COOR.
DETAILED DESCRIPTION OF THE INVENTION
Preferred substituents within the scope of the present invention include those wherein
Y 1 and Y 2 are independently hydroxy or alkoxy containing up to 8 carbon atoms;
R 1 is H; alkyl having 1 to 8 carbon atoms; phenyl-alkyl wherein the alkyl has 1 to 4 carbon atoms, and more preferably phenethyl; or indanyl, e.g. 2-indanyl;
R 2 is H; alkyl having 1 to 8 carbon atoms; or an alkyl group having 1 to 8 carbon atoms, which is substituted with amino or an amino derivative such as --NH--C(NH 2 )=NH, or ##STR3## and R 2 is and more preferably NH 2 (CH 2 ) 4 --. A is --NH 2 ; --OH; phenoxy; alkoxy having up to 6 carbon atoms; --SO 2 NR 1 R 2 wherein R 1 and R 2 are hydrogen, methyl, or C 2--3 alkyl, more preferably both hydrogen;
B is halogen, and more preferably chloro; or--CF 3 ; and E is halogen or hydrogen.
The ring formed by X 1 , X 2 , and the atoms to which they are connected, contains a total of 5, 6 or 7 atoms. In a most preferred embodiment, both X 1 and X 2 are --CH 2 --, thereby forming a proline ring. X 1 or X 2 can be substituted with an R 3 group which is preferably --OH or alkyl containing 1 to 6 carbon atoms. Preferred substituents for R 4 and R 5 are --H, or alkyl having 1 to 2 carbon atoms,
The alkyl groups include straight-chained and branched groups, including methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, amyl, iso-amyl, hexyl, and the like. By "halogen" is meant chloro, bromo, iodo, and fluoro.
Preferred substituents for R 1 and/or R 2 also include cycloalkyl groups, aryl groups, heterocyclic groups, and fused aryl-cycloalkyl groups, as defined herein, any of which can be connected to the main chain of the molecule (1) directly or through an alkylene bridge --(CH 2 ) n --wherein n is 1 to 6. The preferred cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, or norbornyl. The preferred aryl and fused aryl-cycloalkyl groups include phenyl, indolyl, indolino, indanyl, naphthyl, tetrahydronaphthyl, and decahydronaphthyl. Preferred heterocyclic groups include pyridyl, quinolyl, isoquinolyl, tetrahydroquinolyl, tetrahydroisoquinolyl, decahydroquinolyl, decahydroisoquinolyl, pyrrolidyl, pyrrolyl, morpholinyl, furyl, tetrahydrofuryl, furfuryl, benzimidazolyl, thienyl, and imidazolyl. Preferred aryl-alkyl substituents include benzyl and phenethyl. Preferred substituents on the alkyl, cycloalkyl, aryl, and fused aryl-cycloalkyl substituents include alkyl and alkoxy with 1 to 6 carbon atoms, --CF 3 , --OH, --NH 2 , phenoxy, --NR 1 R 2 , --COOH, --CN, --SH, halogen, --NO 2 , and COOR, particularly COO--C 1--6 alkyl.
Compounds according to formula (1) can contain asymmetric centers at the carbon atoms marked thus: C*. Each of these carbon atoms can have an (R) or an (S) configuration, and preferably (S). In the preferred compounds the spiro carbon is (S) or (R) and the other asymmetric carbons are in the (S) configuration. Individual optical diastereoisomers as well as mixtures thereof are considered to be within the scope of this invention. The invention thus covers in particular (S,S,S,S) and (S,S,S,R) compounds and mixtures thereof; as well as (S,S,S) and (S,S,R) compounds and mixtures thereof. When diastereoisomeric products result from the synthetic procedures, the desired diastereoisomeric product can be separated by conventional chromatographic or fractional crystallization methods.
The compounds of formula (1) can be prepared by coupling compounds of formulas (2) and (3) ##STR4## followed by oxidizing the >CHOH group to >C═O and reacting that product with compound (4) ##STR5## Both free --NH 2 groups react with the >C═O group to form the desired spiro linkage. The various substituents on compounds (2), (3) and (4) have been defined above.
It will be recognized by those skilled in this art that the coupling of compounds (2) and (3) can be carried out by conventional peptide linkage techniques, e.g. in the presence of a coupling agent such as DCC (N,N'-dicyclohexylcarbodiimide) or CDI (N,N'-carbonyldiimidazole). Alternatively, one may prefer to convert the --COOH group of compound (2) to --C(O)Cl, and then react the resulting intermediate with compound (3). Alternatively one may preferably convert the compound (2) to the corresponding N-carboxyanhydride (NCA) by allowing (2) to react with phosgene, and then react the resulting N-carboxyanhydride with compound (3) to yield the desired intermediate. One may alternatively prepare the spiro amino ester first by reacting (4) with the ketone derived from (3) via oxidation, and then reacting (2) with the resulting spiro amino ester in any of the above ways (NCA; acid chloride; or active ester-peptide coupling) to yield the desired intermediate. It will further be recognized that the nitrogen atom which is between the carbon atoms to which R 1 and R 2 are attached can be protected with a blocking group such as 2,2,2-trichloroethoxycarbonyl, or benzyloxycarbonyl. The protecting group is subsequently removed, preferably after compounds (2), (3) and (4) have been joined together. Other nitrogen atoms, in substituents such as NH 2 (CH 2 ) 4 --, should be protected and then deprotected in a similar manner. Similarly, Y 1 and Y 2 are preferably converted to ethoxy, t-butoxy, or benzyloxy, before the intermediates are reacted. If the free acid is desired, it is subsequently obtained by removal of the esterifying group in a known manner.
The compounds of the present invention in which one of Y 1 and Y 2 is --OH and the other is alkyl, such as methoxy or ethoxy, are preferably made by reacting compounds (2) and (3) as shown above in which one of Y 1 and Y 2 is the desired alkyl ester, and the other is an easily cleaved ester group such as t-butoxy. The amide intermediate thus prepared is oxidized and reacted with (4) to give the corresponding intermediate which upon a mild acid hydrolysis yields the desired monoester-monoacids.
When Q contains sulfur, the preferred synthetic route is via the acid chloride.
The compounds of this invention form salts with various inorganic and organic acids and bases which are also within the scope of the invention. Such salts include ammonium salts, alkali metal salts like sodium and potassium salts (which are preferred), alkaline earth metal salts like the calcium and magnesium salts, salts with organic bases e.g., dicyclohexylamine salts, N-methyl-D-glucamine, salts with amino acids like arginine, lysine and the like. Also, salts with organic and inorganic acids may be prepared, e.g., HCl, HBr, H 2 SO 4 , H 3 PO 4 , as well as methanesulfonic, toluenesulfonic, maleic, acetic, malic, citric, fumaric and camphorsulfonic acids. The non-toxic physiologically acceptable salts are preferred, although other salts are also useful, e.g., in isolating or purifying the product.
The salts may be formed by conventional means, as by reacting the free acid or free base forms of the product with one or more equivalents of the appropriate base or acid in a solvent or medium in which the salt is insoluble, or in a solvent such as water which is then removed in vacuo or by freeze-drying, or by exchanging the cations of an existing salt for another cation on a suitable ion exchange resin.
The action of the enzyme renin on angiotensinogen, a pseudoglobulin in blood plasma, produces the decapeptide angiotensin I. Angiotensin I is converted by angiotensin converting enzyme (ACE) to the octapeptide angiotensin II. The latter is an active pressor substance which has been implicated as the causative agent in various forms of hypertension in various mammalian species, e.g., rats and dogs. The compounds within the scope of this invention which intervene in the renin -to- angiotensin I -to- angiotensin II sequence inhibit angiotensin I converting enzyme and therefore are useful in reducing or relieving hypertension.
Furthermore, the compounds within the scope of the present invention which possess diuretic activity promote relief from hypertension by promoting diuresis, and consequently have utility in treating congestive heart failure. Compounds within the scope of this invention can also simultaneously possess ACE inhibitory and diuretic activity, which is particularly unexpected in view of the fact that such simultaneous activity cannot be predicted from prior art compounds. Thus by the administration of a composition containing one or a combination of compounds of formula (1) or pharmaceutically-acceptable salts thereof, hypertension in the species of mammal suffering therefrom is alleviated. A single dose, or preferably two to four divided daily doses, provided on a basis of about 0.1 to 100 mg per kilogram per day, preferably about 1 to 50 mg per kilogram per day, is appropriate to reduce blood pressure. The substance is preferably administered orally, but a parenteral route such as subcutaneously, intramuscularly, intravenously or intraperitonealy can also be employed.
The compounds of the invention can be utilized to achieve the reduction of blood pressure by formulating one or more of them in compositions such as tablets, capsules or elixirs for oral administration or in sterile solutions or suspensions for parenteral administration. About 10 to 500 mg of a compound or mixture of compounds of formula (1) or physiologically acceptable salt(s) thereof is compounded with a physiologically acceptable vehicle, carrier, excipient, binder, preservative, stabilizer, flavor, etc., in a unit dosage form as called for by accepted pharmaceutical practice. The amount of active substance in these compositions or preparations is such that a suitable dosage in the range indicated is obtained.
Illustrative of the adjuvants which may be incorporated in tablets, capsules and the like are the following: a binder such as gum tragacanth, acacia, corn starch or gelatin; an excipient such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; a sweetening agent such as sucrose, lactose or saccharin; a flavoring agent such as peppermint, oil of wintergreen or cherry. When the dosage unit form is a capsule, it may contain in addition to materials of the above type a liquid carrier such as a fatty oil. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit. For instance, tablets may be coated with shellac, sugar or both. A syrup or elixir may contain the active compound, sucrose as a sweetening agent, methyl and propyl parabens as preservatives, a dye and a flavoring such as cherry or orange flavor.
Sterile compositions for injection can be formulated according to conventional pharmaceutical practice by dissolving or suspending the active substance in a vehicle such as water for injection, a naturally occurring vegetable oil like sesame oil, coconut oil, peanut oil, cottonseed oil, etc., or a synthetic fatty vehicle like ethyl oleate, and the like. Buffers, preservatives, antioxidants and the like can be incorporated as required.
Specific embodiments of the invention are illustrated in the following Examples.
EXAMPLE 1
A. 4-Hydroxy-L-Proline Ethyl Ester Hydrochloride
To a solution of N-Cbz-4-hydroxy-L-proline ethyl ester (3.29 g) in 40 ml ethanol was added 6 ml of ethanol saturated with gaseous HCl followed by 10% palladium on carbon (0.50 g). The mixture was hydrogenated on a Parr Hydrogenator at 30-40 psi for 3 hours. The solution was filtered over celite and concentrated in vacuo to provide 2.09 g of the crystalline product.
B. N-[N-[(1S)-1-(Ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanyl]-4-hydroxy-L-proline ethyl ester
To N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanine (5.94 g, 13.07 mmol) in 50 ml methylene chloride, under N 2 , was added oxalyl chloride (5.70 ml, 65.33 mmol) and then N,N-dimethylformamide (20 uL). The solution was stirred 3.5 hours and concentrated in vacuo. The residue was diluted with 30 ml methylene chloride and cooled with an ice bath while under N 2 . To this solution was added portionwise a mixture of 4-hydroxy-L-proline ethyl ester hydrochloride (1.96 g, 10.05 mmol) and triethylamine (6.99 ml, 50.25 mmol) in 40 ml methylene chloride. After the addition was complete the solution was slowly warmed to room temperature, stirred 18 hours and concentrated in vacuo. The residue was dissolved in ether and washed with water, 10% HCl, 1N NaOH, and brine, and dried (MgSO 4 ) and concentrated in vacuo. Chromatography of the residue on HPLC, using 50% ethyl acetate in hexanes as eluents, provided 2.44 g (41%) of the oily product.
C. N-[N-[(1S)-1-(Ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanyl]-L-prolin-4-one ethyl ester
To a solution of N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanyl]-4-hydroxy-L-proline ethyl ester (2.21 g, 3.71 mmol) in 30 ml methylene chloride was added pyridinium chlorochromate (PCC) (1.60 g, 7.43 mmol). The mixture was stirred 28 hours and additional PCC (1.60 g) was added. The mixture was stirred 72 hours and the solution was decanted from the solid residue. The residue was triturated with ether. The combined organic solutions were passed through a plug of silica gel. Concentration in vacuo of the filtrate provided 2.1 g (95%) of the oily product which was carried forward without further purification.
D. Spiro[(7-sulfonamyl-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide)-3,4'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanyl]-L-proline ethyl ester]]
To a solution of N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanyl]-L-prolin-4-one ethyl ester (1.01 g, 1.70 mmol) and 1-amino-3-chloro-4,6-benzenedisulfonamide (0.511 g, 1.79 mmol) in 15 ml ethanol was added 2 ml of ethanol saturated with gaseous HCl. The solution was heated to 65° C. for 1.5 hours and concentrated in vacuo. The residue was chromatographed on HPLC using 60% ethyl acetate in hexanes as eluents which provided the solid product.
E. Spiro[(7-sulfonamyl-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide)-3,4'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-L-alanyl]-L-proline ethyl ester]] hydrochloride
To a solution of spiro[(7-sulfonamyl-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide)-3,4'-[N-[N-[(1S)-1- (ethoxycarbonyl)-3-phenylpropyl]-N-(2,2,2-trichloroethoxycarbonyl)-L-alanyl]-L-proline ethyl ester]] (0.55 g) in 7 ml glacial acetic acid was added zinc dust (1.5 g). The mixture was stirred at room temperature for 1.1 hour, filtered over celite and gaseous HCl was added to the filtrate. The solution was concentrated in vacuo. The residue was triturated with 20% ethyl acetate in ether which provided the crystalline product, having the following structural formula: ##STR6##
EXAMPLE 2
Spiro[(7-sulfonamyl-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide)-3,4'-[N-[N-[(1S)-1-(hydroxycarbonyl)-3-phenylpropyl]-L-alanyl]-L-proline]]hydrochloride
To a solution of spiro[(7-sulfonamyl-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide)3,4'-[N-[N-[(1S)-1- (ethoxycarbonyl)-3-phenylpropyl]-L-alanyl]-L-proline ethyl ester]] hydrochloride (0.60 g) in 5 ml ethanol was added aqueous sodium hydroxide (8.3 ml of a 1N solution). The solution stirred at room temperature for 20 hours, acidified to pH 1 with concentrated HCl and extracted with ethyl acetate. The organic layers were washed in brine, and dried (MgSO 4 ) and concentrated in vacuo. Trituration of the residue with 50% ethyl acetate in ether provided 0.51 g of the crystalline product m.p. 198° C. (dec.).
The following compounds, which are within the scope of this invention, are made by the procedures employed in Examples 1-2:
EXAMPLE 3
Spiro [(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2,4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-L-alanyl]-L-proline]] hydrochloride (referring to formula (1): a=d=y=1, x=0).
EXAMPLE 4
Spiro [(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2,4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-α(1S)-1-(hydroxycarbonyl)-3-phenylpropyl]-L-lysyl]-L-proline]] dihydrochloride (formula (1): a=d=y=1, x=0).
EXAMPLE 5
Spiro [(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-L-valyl]-L-proline]] hydrochloride (formula (1): a=d=1=y-1, x=0).
EXAMPLE 6
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-[(1S)-1-(hydroxycarbonyl)-3-phenylpropyl]-L-phenylalanyl]-L-proline]] hydrochloride (formula (1): a=d=y=1; x=0.
EXAMPLE 7
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-[(1S)-1-(hydroxycarbonyl)- 3-methylbutyl]-L-alanyl]-L-proline]] hydrochloride (formula (1): a=d=y=1, x=O).
EXAMPLE 8
Spiro [(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-[(1S)-1-(ethoxycarbonyl)-1-(2,3-dihydro-lH-inden-2-yl) methyl]-L-alanyl]-L-proline]] hydrochloride (formula (1): a=d=y=1; X=0).
EXAMPLE 9
Spiro [(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3- phenylpropyl]-L-alanyl]-L-pipecolinic acid]] hydrochloride (formula (1): a=2, d=y=1, x=0).
EXAMPLE 10
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 5'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-L-alanyl-L-pipecolinic acid]] hydrochloride (formula (1): d=2, a=y=1, x=0).
EXAMPLE 11
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N α-[(1S)- 1-(hydroxycarbonyl)-3-phenylpropyl]-L-lysyl]- L-pipecolinic acid]] dihydrochloride (formula (1): a=2, d=y=1, x=0).
EXAMPLE 12
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 5'-[N-[N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl)-L-alanyl]- L-homopipecolinic acid ]] hydrochloride- (formula (1): a=d=2, y=1, x=0).
EXAMPLE 13
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-[N-α-[(1S)-1-(hydroxycarbonyl)-3-phenylpropyl]-L-lysyl]-L-homopipecolinic acid]] dihydrochloride (formula (1): a=3, d=y=1, x=0).
EXAMPLE 14
Spiro[(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide-3, 4'-[N-[N-[(1S)-1-(hydroxycarbonyl)-1- (2,3-dihydro-1H-inden-2-yl)methyl]-L-alanyl]-L-homopipecolinic acid]] hydrochloride (formula (1): a=3, d=y=1, x=0).
EXAMPLE 15
Spiro [(7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-(3-mercapto-2-methylpropanoyl)-L-proline]] (formula (1): a=d=y=1, x=0).
EXAMPLE 16
Spiro (7-sulfonamyl-6-chloro-3, 4-dihydro-2H-1, 2, 4-benzothiadiazine-1, 1-dioxide)-3, 4'-[N-(3-trimethylacetylthio-2- methylpropanoyl)-L-proline]] (formula (1): a=d=y=1, x=0).
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Compounds having the general structure ##STR1## and their pharmaceutically acceptable salts, wherein the substituents are defined herein, which exhibit antihypertensive activity.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part patent application taking priority from nonprovisional application Ser. No. 10/976,448, filed on Oct. 28, 2004 now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates generally to a wall restraint system, and more particularly to an apparatus for bracing a concrete or masonry wall that is bowing or has begun to buckle as a result of hydrostatic pressure and/or other external forces as may occur with the foundation or basement wall of a building.
Modern foundations are typically formed of concrete block walls or poured concrete walls. Concrete block walls are constructed of concrete blocks stacked with alternating vertical joints using mortar between the joints to hold the blocks together. Poured concrete walls are constructed by setting concrete wall forms, installing steel reinforcing bars, and pouring concrete into the forms to create walls. Poured concrete walls are desirous for their strength, stability, and endurance. However, they do trap moisture, creating a wetter, more humid basement. Concrete block walls are desirous for their openings and pores allowing moisture to escape, creating a drier, less humid basement. Unfortunately, concrete block walls tend to be less resistant to lateral forces attributed to hydrostatic pressures, causing the walls to buckle, crack, and potentially collapse.
The need for reinforcing concrete masonry walls is prevalent in areas where there is a high water table, heavy absorbent clay soil, and freezing and thawing of soil. Structures built in these areas tend to experience higher instances of foundation problems, including the bowing and buckling of concrete masonry walls. The prior art bracing system solution for bowing and buckling of concrete masonry walls includes installing a series of vertical support reinforcing restraints along the bowed or buckled wall. These restraints are typically engineered steel beams that are bolted to the floor joist and bolted through the basement floor or footing with brackets. A top bracket is generally welded to the upper end of the beam, while a bottom bracket is welded to the bottom end of the beam. Additionally, holes must be drilled through the beams or brackets for securing the beam to the basement floor or floor joist. Currently, each beam is custom fabricated for each job and welded to the brackets. Such requirements substantially increase the labor and costs associated with installing these prior art bracing systems.
Additionally, U.S. Pat. No. 4,757,651 to Crites discloses a wall system; U.S. Pat. No. 5,845,450 to Larsen discloses a bracing system; U.S. Pat. No. 6,662,505 to Heady et al. discloses an apparatus and method of straightening and supporting a damaged wall; and patent application no. 2006/0080926 to Resch et. al. discloses a wall bracing system and method of supporting a wall.
Therefore, there is a need for an economical wall restraining system that is less expensive and easier to install than the custom fabricated prior art bracing systems requiring welding and drilling during installation on buckled concrete masonry walls.
SUMMARY OF THE INVENTION
The present invention preferably comprises a vertically disposed beam, which is positioned in engaging relation with a vertical concrete masonry wall and secured in place by a bottom bracket and a top bracket. The beam reinforces the wall and prevents further bowing, buckling, or potentially collapsing of the wall. One end of the beam is preferably secured to the basement floor or footings by a bottom bracket. The bottom bracket preferably receives the lower end of the beam therein and is secured to the basement floor or footings with fasteners. The upper end of the beam is preferably secured against the wall by a top bracket which, in turn, is secured to one of the overhead floor joists. The top bracket preferably engages the upper end of the beam, is secured to a floor joist, and urges the beam against the wall. The top bracket is preferably further secured to the floor joist by fasteners.
The wall restraint system of the present invention does not need any fabrication, customization, welding or drilling as required in the prior art bracing systems. The present invention utilizes less expensive, easy to assemble parts.
Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the accompanying drawings and detailed description thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an embodiment of a wall restraint system attached to a floor joist in accordance with the present invention;
FIG. 2 is a perspective view of another embodiment of a wall restraint system attached to a floor joist and positioned against a wall in accordance with the present invention;
FIG. 3A is an enlarged front perspective view of an embodiment of a top bracket utilized in the wall restraint system of FIG. 1 ;
FIG. 3B is an enlarged rear perspective view of the top bracket of FIG. 3A ;
FIG. 4A is an enlarged front perspective view of another embodiment of a top bracket utilized in the wall restraint system of FIG. 2 ;
FIG. 4B is an enlarged rear perspective view of the top bracket of FIG. 4A ;
FIG. 5 is an enlarged perspective view of a bottom bracket utilized in the wall restraint systems of FIGS. 1 , 2 , 6 , 6 a , 8 , 8 a , 14 and 17 ;
FIG. 5 a is an enlarged perspective view of another embodiment of a bottom bracket utilized in the wall restraint systems of FIGS. 1 , 2 , 6 , 6 a , 8 , 8 a , 14 and 17 ;
FIG. 6 is a perspective view of yet another embodiment of a wall restraint system attached to a floor joist in accordance with the present invention;
FIG. 6 a is a perspective view of yet another embodiment of a wall restraint system attached to a floor joist and positioned against a wall in accordance with the present invention;
FIG. 7 is an enlarged front perspective view of yet another embodiment of a top bracket utilized in the wall restraint system of FIG. 6 ;
FIG. 7 a is an enlarged perspective view of a top bracket utilized in the wall restraint system of FIG. 6 a in accordance with the present invention;
FIG. 7 b is an enlarged perspective view of an anchor washer utilized in the wall restraint system of FIG. 6 a in accordance with the present invention;
FIG. 8 is a side view of yet another embodiment of a wall restraint system attached to a floor joist in accordance with the present invention;
FIG. 8 a is a side view of yet another embodiment of a wall restraint system attached to a floor joist in accordance with the present invention;
FIG. 9 is a bottom view of the top bracket of the wall restraint system of FIG. 8 ;
FIG. 9 a is a bottom view of the top bracket of the wall restraint system of FIG. 8 a;
FIG. 10 is a front view of the top bracket of the wall restraint system of FIG. 8 ;
FIG. 10 a is a front view of the top bracket of the wall restraint system of FIG. 8 a;
FIG. 11 is an enlarged side view of yet another embodiment of a top bracket utilized in the wall restraint system of FIG. 8 ;
FIG. 11 a is an enlarged side view of yet another embodiment of a top bracket utilized in the wall restraint system of FIG. 8 a;
FIG. 12 is a front view of the top bracket of FIG. 11 ;
FIG. 12 a is a front view of the top bracket of FIG. 11 a;
FIG. 13 is a bottom view of the top bracket of FIG. 11 ;
FIG. 13 a is a bottom view of the top bracket of FIG. 11 a;
FIG. 14 is a bottom view of the top bracket of FIG. 11 ;
FIG. 15 is a side view of yet another embodiment of a wall restraint system utilizing an offset top connector in accordance with the present invention;
FIG. 15 a is a bottom view of a wall restraint system utilizing an offset top connector in accordance with the present invention;
FIG. 16 is an enlarged end view of an end cap receiver of a wall restraint system of FIG. 15 ;
FIG. 16 a is an enlarged side view of an end cap receiver of a wall restraint system of FIG. 15 ;
FIG. 17 is an enlarged top view of an adjustment yoke of a wall restraint system of FIG. 15 ;
FIG. 17 a is an enlarged end view of an adjustment yoke of a wall restraint system of FIG. 15 ;
FIG. 18 is a side view of a wall restraint system utilizing an offset beam in accordance with the present invention;
FIG. 18 a is a bottom view of a wall restraint system utilizing an offset beam in accordance with the present invention; and
FIG. 19 is an enlarged perspective view of an offset beam of a wall restraint system of FIG. 17 .
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, FIG. 1 illustrates an embodiment of a wall restraint system 10 attached to a floor joist 18 in accordance with the present invention. The wall restraint system 10 preferably includes a vertically disposed beam 12 which is positioned in engaging relation with a vertical concrete masonry wall 22 and secured in place by a bottom bracket 14 and a top bracket 16 . The present invention assumes a basement of conventional construction, which includes a basement floor with concrete masonry walls extending upwardly therefrom. The floor joists for the floor of the building are positioned on top of the concrete masonry walls and are secured at their respective ends to conventional plates as is known in the art.
The beam 12 is preferably a rigid rectangular tubular member constructed of steel having dimensions of 2×4, 2×5 or 2×6, and lengths depending upon the height of the walls for which they are installed. However, beams of various sizes, dimensions, and lengths may be used. The beams are preferably designed to engage a basement wall for reinforcing the wall and preventing the wall from bowing, buckling and/or collapsing. One surface of the beam bears against the wall, providing a strong bearing surface for the wall. Several beams may be required to bolster a single wall against buckling. In this arrangement, the beams will be spaced apart a few or several feet as required. The beams engage the wall and cooperate with the brackets and floor joists to prevent further buckling and collapse.
One end of the beam 12 is preferably secured to a floor or footings adjacent the wall by a bottom bracket 14 . The bottom bracket 14 preferably receives the lower end of the beam 12 therein and is secured to the floor or footings with fasteners. The beam 12 is preferably hollow to receive a portion of the bottom bracket 14 therein.
The upper end of the beam 12 is preferably secured against the wall by a top bracket 16 which, in turn, is secured to one of the overhead floor joists 18 by fasteners. FIGS. 1 , 3 A and 3 B show one embodiment of a top bracket 16 , while FIGS. 2 , 4 A and 4 B show another embodiment of a top bracket 26 . The top bracket 16 engages the upper end of the beam 12 , is secured to an adjacent floor joist 18 , and urges the beam 12 against the wall.
FIG. 2 illustrates another embodiment of a wall restraint system 30 attached to a floor joist 18 and positioned against a wall 22 in accordance with the present invention. The only difference between the wall restraint system 10 of FIG. 1 and the wall restraint system 30 of FIG. 2 is the top bracket. FIG. 1 shows one embodiment of the top bracket 16 , while FIG. 2 shows another embodiment of the top bracket 26 .
The wall restraint system 30 preferably includes a vertically disposed beam 12 which is positioned in engaging relation with a vertical concrete masonry wall 22 and secured in place by a bottom bracket 14 and a top bracket 26 . The floor joist 18 is positioned upon the top of the concrete wall 22 and is secured at its respective end to conventional plates 20 , 24 .
One end of the beam 12 is preferably secured to the basement floor or footings adjacent the basement wall by a bottom bracket 14 . The bottom bracket 14 preferably receives the lower end of the beam 12 therein and is secured to the floor or footings with fasteners. The beam 12 is preferably hollow to receive a portion of the bottom bracket 14 therein.
The upper end of the beam 12 is preferably secured against the wall by a top bracket 26 which, in turn, is secured to one of the overhead floor joists 18 by fasteners. The top bracket 26 engages the upper end of the beam 12 , is secured to an adjacent floor joist 18 , and applies a force against the upper end of the beam 12 toward the wall 22 .
FIGS. 3A and 3B illustrate front and rear perspective views of an embodiment of a top bracket 16 utilized in the wall restraint system 10 of the present invention. The top bracket 16 preferably comprises a substantially flat rectangular base plate 32 having a front surface and a rear surface, parallel longitudinal edges, and parallel transverse edges. The top bracket 16 also preferably includes two opposing flanges 34 , 36 extending outwardly from the front surface of the base plate 32 at each of the parallel longitudinal edges perpendicular from the base plate 32 . The flanges 34 , 36 each including rectangular openings 38 , 40 formed therethrough for receiving the beam 12 therein. The openings 38 , 40 may preferably be constructed to fit a 2×4 inch rectangular beam, a 2×5 inch rectangular beam, or a 2×6 inch rectangular beam.
The base plate 32 further preferably includes a plurality of prongs 44 and a pair of openings 42 disposed on opposite sides of the prongs 44 . The triangularly-shaped prongs 44 preferably have sharp points extending outwardly from the rear surface of the base plate 32 for biting into the floor joist 18 . The pair of openings 42 extending through the base plate 32 are for receiving fasteners therein for further securing the bracket 16 to the floor joist 18 .
FIGS. 4A and 4B illustrate front and rear perspective views of another embodiment of a top bracket 26 utilized in the wall restraint system 30 of the present invention. The top bracket 26 preferably comprises a substantially flat rectangular base plate 46 having a front surface and a rear surface, parallel longitudinal edges, and parallel transverse edges. The top bracket 26 also preferably includes an L-shaped portion 48 , 50 extending outwardly from one of the parallel transverse edges for receiving the beam 12 . The L-shaped portion having a first section 48 extending perpendicular from the front surface of the base plate 46 and a second section 50 extending perpendicular from the end of the first section 48 and parallel to the base plate 46 . The L-shaped portion 48 , 50 may be constructed to fit a 2×4 inch rectangular beam, a 2×5 inch rectangular beam, or a 2×6 inch rectangular beam.
The base plate 46 further preferably includes a plurality of prongs 54 and a pair of openings 52 extending through the base plate 46 and disposed on opposite sides of the prongs 54 . The triangularly-shaped prongs 54 preferably have sharp points extending outwardly from the rear surface of the base plate 46 for biting into the floor joist 18 . The pair of openings 52 extending through the base plate 46 are for receiving fasteners therein for further securing the bracket 26 to the floor joist 18 .
FIG. 5 illustrates an enlarged perspective view of an embodiment of a bottom bracket 14 utilized in the wall restraint systems of the present invention. The bottom bracket 14 preferably comprises a substantially flat rectangular base plate 56 having a top surface and a bottom surface, and a U-shaped or rectangularly-shaped portion 58 extending upwardly perpendicular from the base plate 56 for insertion into the hollow beam 12 . As mentioned earlier, the beam is preferably hollow, with the beam sides fitting snuggly around the U-shaped or rectangularly-shaped portion 58 of the bottom bracket 14 . The base plate 56 further preferably includes a pair of openings 60 extending therethrough and disposed on opposite sides of the U-shaped or rectangularly-shaped portion 58 . The pair of openings 60 extending through the base plate 56 are for receiving fasteners therein for securing the bracket 14 to the basement floor or basement footings. The bottom bracket 14 is also preferably provided in several sizes as required to accommodate the varying sizes of the beam 12 . FIG. 5 a illustrates the bottom bracket 14 being modified by forming a pair of chamfered surfaces 59 on the rectangularly-shaped portion 58 to create a bottom bracket 14 ′. The pair of chamfered surfaces 59 allow for angular adjustment of the beam 12 relative to the bottom bracket 14 ′.
FIG. 6 is a perspective view of yet another embodiment of a wall restraint system 70 attached to a floor joist in accordance with the present invention. The wall restraint system 70 of FIG. 6 is the same as the wall restraint systems 10 , 30 of FIGS. 1 and 2 except for the top bracket 72 . FIG. 7 illustrates an enlarged front perspective view of yet another embodiment of a top bracket 72 utilized in the wall restraint system 70 of FIG. 6 . The top bracket 72 preferably comprises a substantially flat rectangular base plate 74 having a front surface and a rear surface, parallel longitudinal edges, and parallel transverse edges. The top bracket 72 also preferably includes an L-shaped portion 76 , 78 extending outwardly from one of the parallel transverse edges for receiving the beam 12 . The L-shaped portion having a first section 76 extending perpendicular from the front surface of the base plate 74 and a second section 78 extending perpendicular from the end of the first section 76 and parallel to the base plate 74 . The L-shaped portion 76 , 78 may be constructed to fit a 2×4 inch rectangular beam, a 2×5 inch rectangular beam, or a 2×6 inch rectangular beam. The bracket 72 further includes at least two bracing members 84 extending between the front surface of the base plate 74 and the first section 76 of the L-shaped portion. The at least two bracing members 84 add strength and help support the bracket 72 .
The base plate 74 further preferably includes a plurality of prongs 80 and a pair of openings 82 extending through the base plate 74 and disposed on opposite sides of the prongs 80 . The triangularly shaped prongs 80 preferably have sharp points extending outwardly from the rear surface of the base plate 74 for biting into the floor joist 18 . The pair of openings 82 extending through the base plate 74 are for receiving fasteners therein for further securing the bracket 72 to the floor joist 18 . The plurality of prongs 80 are shown has having a triangular shape, but could be any suitable shape.
FIG. 6 a illustrates a perspective view of a modified wall restraint system 70 ′. FIG. 7 a illustrates an enlarged front perspective view of a modified top bracket 72 ′ used in the modified wall restraint system 70 ′. The wall restraint system 70 is modified by forming an anchor hole 85 through the first section 76 . A threaded fastener 87 is inserted through the anchor hole 85 and threaded into the beam 12 . FIG. 7 b illustrates an anchor washer 73 . The anchor washer 73 is preferably retained on an opposite side of the floor joist 18 by inserting two fasteners 75 through the top bracket 72 or modified top bracket 72 ′, the floor joist 18 and the anchor washer 73 and securing it thereto with two nuts 77 or the like. The anchor washer 73 includes the pair of openings 82 and the plurality of triangular shaped prongs 80 . The plurality of triangular shaped prongs in the anchor washer 73 and the top bracket 72 or modified top bracket 72 ′ prevent the fasteners 75 from splitting the floor joist 18 , when force is applied to the top bracket 72 or modified top bracket 72 ′.
FIG. 8 illustrates a side view of still another embodiment of a wall restraint system 90 attached to a floor joist 92 and positioned against a wall 94 in accordance with the present invention. FIG. 9 is a bottom view of the top bracket 98 of the wall restraint system 90 of FIG. 8 . FIG. 10 is a front view of the top bracket 98 of the wall restraint system 90 of FIG. 8 . The wall restraint system 90 preferably includes a vertically disposed beam 96 , which is positioned in engaging relation with the wall 94 and secured in place by a bottom bracket (not shown) and a top bracket 98 . The floor joist 92 is positioned upon the top of the wall 94 and is secured to the bracket 98 by a plurality of fasteners 100 , 102 .
One end of the beam 96 is preferably secured to the basement floor or footings adjacent the basement wall by a bottom bracket (not shown). The bottom bracket preferably receives the lower end of the beam 96 therein and is secured to the floor or footings with fasteners. The beam 96 is preferably hollow to receive a portion of the bottom bracket therein. The upper end of the beam 96 is preferably secured against the wall 94 by a top bracket 98 , which, in turn, is secured to one of the overhead floor joists 92 by fasteners 100 , 102 . The top bracket 98 engages the upper end of the beam 96 , is secured to an adjacent floor joist 92 . FIG. 8 a illustrates a side view of a modified wall restraint system 90 ′. FIG. 9 a is an enlarged bottom view of a modified top bracket 98 ′ of the wall restraint system 90 ′. FIG. 10 a is an enlarged front view of the modified top bracket 98 ′ of the wall restraint system 90 ′.
FIG. 11 is an enlarged side view of still another embodiment of a top bracket 98 utilized in the wall restraint system of FIG. 8 . FIG. 12 is a front view of the top bracket 98 of FIG. 11 . FIG. 13 is a bottom view of the top bracket 98 of FIG. 11 . The top bracket 98 preferably comprises two spaced apart parallel side members 104 , 106 , each having a pair of parallel longitudinal edges and a pair of parallel transverse edges. The top bracket 98 also preferably includes a connecting member 108 connection a portion of a longitudinal edge of a first parallel side member 104 to a portion of a longitudinal edge of a second parallel side member 106 , and a transverse member 110 extending outwardly at a perpendicular angle from one end of the connecting member 108 between the pair of parallel transverse edges of the parallel side members 104 , 106 . The parallel side members 104 , 106 each have at least two openings 112 , 114 extending therethrough for receiving fasteners 100 therein to fasten the bracket 98 to the floor joist 92 . The connecting member also includes at least one opening 116 extending therethrough for receiving a fastener 102 therein to fasten the bracket 98 to the bottom of the floor joist 92 .
FIG. 11 a is an enlarged side view of the modified top bracket 98 ′; FIG. 12 a is an enlarged front view of the modified top bracket 98 ′ and FIG. 13 a is an enlarged bottom view of the modified top bracket 13 a . The top bracket 98 is modified by attaching a nut 118 or the like to the connecting member 108 . With reference to FIG. 8 a , a threaded bolt 119 is threaded into the nut 118 . The threaded bolt 119 is threaded into the nut 118 to force an upper end of the beam 96 against a top of the wall 94 to correct any misalignment thereof.
FIG. 15 illustrates a side view of a wall restraint system 120 utilizing an offset top connector 122 . FIG. 15 a illustrates a bottom view of the wall restraint system 120 . The offset top connector 122 includes the beam 96 , an adjustment yoke 124 , a threaded end cap 126 , a thrust tube 128 , the top bracket 98 and at least two floor joist supports 129 . Referring briefly to FIGS. 17 and 17 a , the adjustment yoke 124 includes a yoke 130 and a threaded stud 132 . The threaded stud 132 includes a hex perimeter 134 . An end of the thread stud 132 is pivotally retained in the yoke 130 by flaring an end of the threaded stud 132 or with any other suitable process. Referring briefly to FIGS. 16 and 16 a , the threaded end cap 126 is inserted into one end of the thrust tube 128 . The threaded end cap 126 includes an inner perimeter flange 136 and an inner thread 138 . The inner perimeter flange 136 is sized to be received by an inner perimeter of the thrust tube 128 . The inner thread 138 may be a hex nut 135 attached to the inner perimeter flange 136 or extra material extending from the inner perimeter flange 136 . The inner thread 138 is sized to threadably receive the threaded stud 132 . The thrust tube 128 is bolted to two floor joists 140 with at least two fasteners 142 . The top bracket 98 axially retains the other end of the thrust tube 128 . A single floor beam support 129 is attached between two adjacent floor joists 140 with any suitable method. The floor beam support 129 prevents the floor joists from flexing due to a perpendicular force from the thrust tube 128 . However, other methods of preventing flexing of the floor joists 140 may also be used. The top bracket 98 is bolted to one of the at least two floor beam supports 129 with fasteners 100 and a fastener 101 through the traverse member 110 . The hex perimeter 134 is rotated to force the beam 96 against the wall 94 .
FIG. 18 illustrates a side view of a wall restraint system 144 utilizing an offset beam connector 146 . FIG. 18 a illustrates a bottom view of the wall restraint system 144 . Referring briefly to FIG. 19 , the offset beam 146 includes the beam 96 , a pair of fastening plates 148 , an offset member 150 and a plurality of fasteners 152 . The offset beam 146 is used, when piping 153 or the like is obstructing attachment of the top bracket 98 or modified top bracket 98 ′. The offset member 150 includes a first tube 154 and a second tube 156 . One end of the first tube 154 is mitered with a 45 degree angle and one end of the second tube 156 is mitered with a 45 degree angle. The mitered ends of the first and second tubes are preferably attached to each other with welding or any other suitable process. A single fastening plate 148 is attached to an end of the beam 96 and a non-mitered end of the first tube 154 on opposing sides thereof with the plurality of fasteners 152 . The single floor beam support 129 is attached between two adjacent floor joists 140 with any suitable method. The floor beam support 129 prevents the floor joists from flexing due to a perpendicular force from the top bracket 98 , 98 ′. The top bracket 98 , or modified top bracket 98 ′ is attached to one of the at least two floor beam supports 129 with at least two fasteners 100 . A non-mitered end of the second tube 156 is retained in the top bracket 98 , 98 ′. The top bracket 98 , 98 ′ retains the offset member 150 . The threaded bolt 119 of the modified top bracket 98 ′ is rotated to force the beam 96 against the wall 94 .
While the invention has been described with reference to preferred embodiments, those skilled in the art will appreciate that certain substitutions, alterations and omissions may be made to the embodiments without departing from the spirit of the invention. Accordingly, the foregoing description is meant to be exemplary only, and should not limit the scope of the invention as set forth in the following claims.
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An apparatus for bracing a masonry wall that is bowing or has begun to buckle as a result of hydrostatic pressure and/or other forces as may occur with the foundation or basement wall of a building. The wall restraint system includes a vertically disposed beam, which is positioned against a vertical concrete masonry wall and secured in place by a bottom bracket and a top bracket. The beam reinforces the wall and prevents further bowing, buckling, or potentially collapsing of the wall. One end of the beam is secured to the floor by a bottom bracket. The bottom bracket preferably receives the lower end of the beam. The upper end of the beam is secured against the basement wall by a top bracket or offset connector, which in turn is secured to one of the overhead floor joists. The beam may be offset to avoid piping or the like.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to apparatus for operating high speed electronic devices at cryogenic temperatures, and more particularly, for interfacing such devices electrically to room temperature apparatus.
2. Description of Related Art
U.S. Pat. No. 4,401,900 to Faris, entitled "Ultra High Resolution Josephson Sampling Technique," shows a sampling technique with a time resolution of 5 picoseconds and sensitivity of 10 uV. This was demonstrated experimentally using a cryogenic sampling system. The time resolution of this system is extendable to the sub-picosecond domain, limited ultimately by the intrinsic switching speed of the Josephson device used as the sampling gate. This switching speed can in principle be as little as 0.09 picoseconds. The sampling technique is not restricted to measuring only those waveforms produced in a cryogenic environment. Rather, it can be used to measure waveforms from various sources, such as x-rays, optical photons, or electrical waveforms produced by room-temperature sources, if a suitable interface is available.
In order to measure electrical waveforms produced by room temperature devices, or indeed to interface any low temperature electronic device to a room temperature electronic device, the interface scheme must satisfy the electrical, mechanical, and temperature constraints discussed below:
Electrical Constraints. When operating at high frequencies and extremely short pulse durations, any power lost in the transmission line between the low temperature circuit and the room temperature circuit will degrade the signal transfer. This degradation appears as pulse dispersion or pulse spreading. To minimize loss, the transmission lines should be made of a low resistance material, be as short as possible, and have the largest possible cross sectional area. The latter constraint is limited by the further constraint that the width of the transmission line should not exceed the wavelength of the maximum frequency of interest, because larger conductors will waveguide and cause geometric losses.
Mechanical Constraints. Since one end of the transmission line will be operating at extremely low temperatures and the other end will be operating at room temperatures, it is important that the transmission line be able to withstand that temperature difference. Thus, the bond between the transmission line and the low temperature device should be able to withstand that low temperature, and the seal through which the transmission line passes between the low temperature volume and the room temperature volume should also be able to withstand the necessary temperatures. These elements should also be able to withstand repeated cycling from room temperature to low temperature for maintenance, replenishment of helium supply, and general everyday use. Additionally, the temperature coefficient of expansion of the transmission lines should closely match that of the low temperature device, and the construction should be such as to permit the apparatus to tolerate vibration and temperature-induced changes in transmission line length (collectively referred to herein as "movement").
Temperature Constraints. In order to prevent extensive heat transfer from the room temperature volume to the low temperature volume, the transmission lines should be as long as possible. This is directly contrary to the electrical constraints which favor short transmission lines. The transmission lines should also be made of a material which has low thermal conductivity. Since low thermal conductivity usually implies low electrical conductivity, this constraint, too, is contrary to the electrical constraints.
Workers in the field of superconducting electronics typically achieve the necessary temperatures by immersing their circuits in liquid helium. See, for example, Hamilton, "High-Speed, Low-Crosstalk Chip Holder for Josephson Integrated Circuits," IEEE Trans. on Instrumentation and Measurement, Vol. IM-31, pp. 129-131 (1982). The arrangement shown therein involves attaching several coaxial cables to a Josephson Junction chip which is to be immersed in a liquid helium dewar. See also Hamilton et al., IEEE Transactions on Magnetics, MAG-17, pp. 577-582 (1981), in which a low-temperature chip is inserted partially inside a coaxial line to couple the signals therethrough to the roomtemperature devices. Although not mentioned in the reference, it is believed that the low-temperature chip is then immersed in liquid helium. Both arrangements are constrained to have large coaxial lines which have high thermal conductivity. In order to avoid heat losses, the lines are therefore constrained to be long. In addition, these arrangements cannot be adapted easily to planar chips. Furthermore, at least the latter system is constrained to couple only one line to a chip, which limits the system in utility.
An attempt to deal with the constraints described above appears in U.S. Pat. No. 4,498,046 to Faris. The interface described therein includes a pass-through liquid-helium-tight vacuum seal which consists of a flange and two half-cylindrical fused quartz portions, unequal in length, which act as a pass-through plug from a liquid-helium filled cryostat to a vacuum chamber. Fused quartz, while thermally non-conductive, forms a low loss dielectric substrate for conductive copper striplines which are patterned on the flat surface of the longer portion. The coefficient of expansion of fused quartz is small and relatively well matched to that of silicon, which is used for Josephson and semiconductor chip substrates.
The two fused quartz half-cylinder portions of the pass-through plug are arranged so that the portion with the copper striplines extends sufficiently beyond its mating half-cylinder portion on both ends to provide two platforms at opposite ends of the plug. The low temperature semiconductor chip or device is mounted on one of these platforms and the room temperature chip or device is mounted on the other. The cylindrical geometry was chosen in order to minimize stress on cement used to seal the chamber wall around the pass-through. The planar nature of the striplines allows low inductance connections to be made directly to the two chips which are also planar. The low inductance contacts are copper spheres or other rigid probes, about 100 um in diameter or smaller, which penetrate solder pads on the chips when forced into contact by mechanical pressure. The wall of the cryostat is sealed around the pass-through with a thin layer of non-conductive cement. In operation, the two chips are mounted on the platforms and the pass-through is inserted through the cryostat wall such that the low temperature chip is immersed in liquid helium in the cryostat and the room temperature chip is disposed inside the vacuum chamber. A heating element and thermocouple are placed near the position of the room temperature chip in order to warm it. This chamber must be evacuated in order to prevent frosting of water and other gases on the plug, and also to provide adequate insulation for the cryostat.
The '046 apparatus has numerous problems which render it costly, unreliable and impractical to use in most applications. First, the only method described in the '046 patent for cooling the low temperature device involves immersing it in liquid helium. It is advantageous, however, to be able to cool such devices using a closed cycle refrigerator (CCR), which is a refrigeration device that is complete unto itself, and is simply plugged into an ordinary AC wall socket.
Second, the apparatus requires at least two seals, one between the cryostat and the vacuum chamber, and one between the vacuum chamber and the external environment. At least the first of these seals is extremely difficult to create, because it must operate at cryogenic temperatures, must be able to be cycled many times between cryogenic and room temperatures, and must be able to withstand a certain amount of vibration without breaking. Due to the small size of the helium atom, it can pass through extremely small cracks in the seal and can even pass through most materials which are not cracked. This severely limits the types of seals which can be used.
Third, since the low temperature chip is fabricated on a silicon substrate and the transmission line is fabricated on a fused quartz substrate, the two elements must usually be made separately and then mechanically and electrically bonded together. These additional steps are costly. In addition, even though their respective temperature coefficients of expansion are close, the mere fact that the materials are different requires some mismatch which degrades the electrical connection and the mechanical reliability of the bond.
Fourth, because multiple sealed layers of chambers and insulating material are required, the transmission line which carries electrical signals between the two chips must be very long.
Fifth, the pass-through of the '046 apparatus has to be cylindrical in order to obtain a good seal. This renders it difficult to manufacture, and requires special geometries such as that shown in FIG. 3E of the '046 patent.
Finally, the chips used in the '046 apparatus cannot be easily plugged in or out in order to change them.
It is known in the field of optics that devices which need to operate at extremely low temperatures may be placed in thermal contact with a cold surface which is inside a vacuum chamber. A product which may be used for this application is the Heli-Tran, made by Air Products and Chemicals, Inc., Allentown, PA. It comprises a flexible insulated tube connected at one end to a liquid helium dewar. The free end of the tube is closed and terminates in a metal block to which a sample may be attached. The sample and the metal block are disposed inside a vacuum chamber attached to the end of the tube. Until now, however, such a product has not been used in connection with a low temperature circuit to be connected with a room temperature circuit by a high performance transmission line. See also U.S. Pat. No. 3,894,403 to Longsworth, in which an apparent variation of the Heli-Tran structure is shown cooling a superconducting magnet. Even there the magnet is immersed in liquid helium.
The inability of the above arrangements to effectively satisfy the constraints described above derives in large measure from a belief among workers in the field that immersion in liquid helium is the only feasible way to cool a low temperature circuit. In fact, however, the method and apparatus of the present invention is far more effective and better satisfies the constraints.
SUMMARY OF THE INVENTION
It is an object of the invention to provide apparatus for electrically interfacing a circuit operated at low temperatures with a circuit operated at room temperatures.
It is another object of the invention to provide an electrical interface not subject to the foregoing problems.
It is another object of the invention to provide a low temperature to room temperature electrical interface which may be used with a closed cycle refrigerator.
It is another object of the invention to provide a low temperature to room temperature electrical interface in which the sealing requirements are manageable.
It is another object of the invention to provide a low temperature to room temperature electrical interface with short transmission lines.
It is another object of the invention to provide a low temperature to room temperature electrical interface in which the low temperature chip and the transmission lines are fabricated on a single substrate.
It is another object of the invention to provide a low temperature to room temperature electrical interface which is pluggable into and out of the operating environment.
The above objects and others are achieved according to the present invention by disposing the low temperature circuit inside a vacuum chamber and in thermal communication with a cooling surface. Transmission lines which are fabricated on the same substrate as the low temperature circuit may pass through the wall of the vacuum chamber to the external environment. A flexible element may be incorporated in the design to accomodate vibration and thermally induced movement of the substrate. In one aspect, the low temperature circuit may be formed on the surface of an elongated fused quartz substrate, at one end thereof, with the transmission lines fabricated on the same substrate. In another aspect of the invention, the low temperature circuit is immersed in thermal grease or another thermally conductive compound in a copper cup which is in thermal communication with the cooling surface. The cup may be attached to the cooling surface through a copper braid or another flexible support. In yet another aspect of the invention, a thermal switch may be provided between the low temperature circuit and the cooling surface. The cooling surface may itself be cooled by any known means, including liquid helium or a CCR.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2, 3, 5 and 6 schematically depict various embodiments of the present invention.
FIG. 4 schematically depicts a thermal switch which may be used with the present invention.
FIGS. 7 and 8 schematically depict apparatus which may be used with the present invention for cooling the cold surface.
FIG. 9 shows a plan view of a chip which may be used with the present invention.
DETAILED DESCRIPTION
In FIG. 1 there is shown a cross sectional schematic view of an apparatus according to the present invention. A wall 8 encloses a vacuum chamber 10, disposed inside of which is a cooling block 12. The cooling block 12 may be made of copper or another thermally conductive material, and may be cooled by any method including a CCR or a liquid helium filled dewar (not shown). A chip 16 having a low temperature circuit fabricated thereon rests on the outside surface of the cooling block 12, in thermal communication therewith. Thermal grease may be used to improve this connection. A group of transmission wires 18 are electrically connected to solder pads on the chip 16 and extend outward through a seal 20 in the wall 8 of the vacuum chamber 10.
The advantages of this structure over the helium dewar structures are apparent. First, since the chip is mounted directly in the vacuum chamber, the transmission wires do not have to pass through many walls and many chambers before reaching the external environment. The wires therefore can be much shorter than in helium dewar methods.
Second, only one noncritical seal, 20, is required, compared to at least two seals in helium dewar methods. The seal is always at or near room temperature and is not in contact with helium. Since there is no seal between a liquid helium filled chamber and a vacuum chamber, the vacuum can be maintained for a longer period of time.
In FIG. 2 there is shown another embodiment of the present invention, in which the low temperature circuit chip and the transmission lines have been replaced by a planar fused quartz substrate strip 30 passing through the wall 8 of the vacuum chamber 10. The substrate strip 30 is thermally bonded inside the chamber to the cooling block 12. Fused quartz is advantageously chosen for the substrate material because of its low thermal conductivity and low temperature coefficient of expansion. A low temperature circuit, designated 32, is fabricated at the end of the substrate which is inside the vacuum chamber and in thermal communication with the cooling block 12, and transmission lines 34, fabricated on the same substrate, extend longitudinally thereon to the outside. A seal 36 surrounds the substrate at the point that it passes through the wall 8 of the vacuum chamber 10. Since the seal is noncritical, there is no necessity that it be circular or that the transmission line substrate be cylindrical. The seal should, however, be flexible in order to accomodate expansion and contraction of the substrate strip 30. The transmission lines 34 may be made of niobium, in which case they may be fabricated in the same process steps during which the circuit 32 is fabricated.
In FIG. 3 there is shown yet another embodiment of the present invention. In addition to the cooling block 12, there is shown a cup 40 which is thermally connected to the cooling block 12 through a braid 42 and a thermal switch 44 for turning on and off the thermal communication between the cup 40 and the cooling block 12. A dividing wall 17 divides the vacuum chamber 10 horizontally at the switch 44 into an upper chamber 13 and a lower chamber 15. The switch 44 passes through the dividing wall 17 and is hermetically sealed thereto. The cup 40, braid 42, cooling block 12 and the top and bottom surfaces of switch 44 are advantageously all made of the same material, preferably copper, in order to prevent any thermal mismatch. Each element is also welded to the next element with a copper weld, such as that shown as 46 (between the cup 40 and the braid 42) and that shown as 48 (between the braid 42 and the thermal switch 44). The cup 40 is filled with thermal grease 50 or any other suitable material. Since the low temperature circuit may be coated with a dielectric, even electrically conducting materials may be used in the cup 40. Thus, the cup 40 may be filled with thermal grease, zinc oxide in a base, a gallium/tin composite or mercury, to name a few examples.
The thermal switch 44 may compromise any of several thermal switches known in the art. One example, shown in FIG. 4, consists of a round copper plate 60 disposed horizontally and to the top surface of which the braid 42 (not shown in FIG. 4) is welded. The plate 60 is supported by a thin stainless steel cylindrical wall 62 which is welded at its base to a bottom plate 61 in thermal communication with the cooling block 12. The wall 62 therefore defines a chamber 64 between the plates 60 and 61. Inside the chamber 64 is a series of concentric copper fins 66, vertically disposed, which are welded alternately to the underside of the plate 60 and to the top of the plate 61. None of the fins 66 make physical contact with the opposite surface. A pipe 68 passes through the wall 8 of the vacuum chamber 13 and connects the inside of the chamber 64 with a reservoir and vacuum pump (not shown). When it is desired to cool a low temperature circuit which is inserted into the thermal grease 50 in the cup 40, helium or another heat transfer fluid is pumped into the chamber 64 through the pipe 68. Heat then travels through the cup 40, braid 42 and copper plate 60 into the copper fins 66 which are welded to the underside of the plate 60. It then travels through the heat transfer fluid to the alternate fins 66, and down into the bottom plate 61 and the cooling block 12. When it is desired to permit the low temperature circuit to warm, the heat transfer fluid is pumped out of the chamber 64 through the pipe 68, so that heat can no longer travel by conduction between the fins 66. The cylindrical wall 62 is made of a material with low thermal conductivity, so that heat transfer from the plate 60 through the wall 62 to the bottom plate 61 will not severely degrade performance of the switch.
A plug assembly 80 shown in FIG. 3 consists of a cap 82 through which passes the same quartz substrate 30 as is shown in FIG. 2. (Only a side view is shown in FIG. 3.) A noncritical epoxy seal 84 surrounds the substrate 30 at the point where it passes through the cap 82. An additional circuit for operation at room temperature may be fabricated on the end of the substrate 30 which is outside the vacuum chamber 10, and/or connection wires may be bonded to the transmission lines at that end of the substrate strip.
When it is desired to operate a low temperature circuit in conjunction with a room temperature circuit according to the apparatus shown in FIG. 3, a quartz substrate strip 30 is cut and the low temperature circuit and transmission lines are fabricated thereon by a known method. The substrate strip 30 is then inserted through a hole in the cap 82 and sealed in place. The substrate strip 30 and the cap 82 form a plug assembly 80, which is interchangeable with any plug assembly made in the same fashion. With the thermal switch 44 turned off and the thermal grease 50 melted, the plug assembly 80 is inserted through a hole 86 in the wall 8 of the upper vacuum chamber 13, such that the end of the substrate strip 30 on which the low temperature circuit is fabricated extends inwardly and is immersed in the grease 50. The hole 86 is slightly smaller than the cap 82 so that when the cap 82 is placed over the hole 86 it will seal the vacuum chamber 13 in a plug-like manner. The seal may be improved by any of a number of known methods, such as through the use of the O-ring shown as 88 in FIG. 3. The chamber 13 is then evacuated and the low temperature circuit is cooled by turning on the thermal switch 44, permitting the cooling block 12 to draw heat away. The thermal grease 50 may freeze, but this does not significantly affect its thermal conductivity. In addition, any expansion or contraction of any element in the apparatus will be accomodated by the braid 42. When it is desired to remove the low temperature circuit and/or replace it with another, it is not necessary to turn off the refrigeration of the cooling block 12. It is only necessary to turn off the thermal switch 44, permitting the thermal grease 50 to warm up and melt. Air is then let into the upper chamber 13 and the plug assembly 80 removed. Since the lower chamber 15 always remains evacuated, the cooling block 12 neither frosts nor picks up unwanted heat.
Another embodiment of the invention will now be described with reference to FIG. 5. The embodiment shown in FIG. 5 is substantially the same as that shown in FIG. 3, except for the chip holder. Instead of the cup 40, braid 42 and plate 60 shown in FIG. 3, the embodiment of FIG. 5 includes a holder 100 made up of a cylindrical wall 102, a floor 104 attached to the bottom thereof, a flexible washer 106 attached to the top of the wall 102, and a cup 108 hanging down into the cylinder, and supported at its top edge by the inside hole of washer 106. The interior of the cylinder may be evacuated (if the washer 106 and wall 102 are thermally conductive) or filled with a compressible fluid to aid in heat transfer. The cup 108 may be filled, as is the cup 40 in FIG. 3, with thermal grease 50 or another suitable material. If the low temperature circuit is fabricated with niobium, the cup should hang down at least 2 mm. The chip holder 100 fits directly on top of the thermal switch 44, and the fins 66 which depend from the top of the switch 44 may be welded directly to the underside of the floor 104 of the chip holder 100. The cup 108, the cylindrical wall 102 and the floor 104 are made of copper or another thermally conductive material If the washer 106 forms part of the heat transfer path then it, too, should be thermally conductive.
The operation of the embodiment shown in FIG. 5 is much the same as that of the embodiment shown in FIG. 3. That is, a plug assembly 80 including the low temperature circuit and transmission lines is constructed and inserted into the upper vacuum chamber 13 such that the low temperature circuit is immersed in the thermal grease 50. Instead of using the braid 42, however, any vibration or thermal expansion or contraction of the substrate strip 30 is accomodated by the flexible washer 106.
While the primary heat sink described in each of the above embodiments is a cooling block, it should be noted that any cooling surface inside the vacuum chamber will suffice. Similarly, where a secondary cooling surface such as a cup is used, any shape appropriate for heat transfer may be used including a flat surface. The braid 42 of FIG. 3, for example, may itself act as the secondary surface by splitting it at its top into two braids, and pressing them directly against the opposite faces of the substrate strip 30 with some thermal grease. As another example, a solid cooling surface may be split into a number of surfaces, each providing a site for one of several substrate strips to be mounted.
In yet another embodiment, related to that shown in FIG. 5, the chip holder 100 itself doubles as the heat sink. In FIG. 6, the chip holder 100 is shown suspended in the vacuum chamber 10 by thermally resistive means not shown. The interior 120 of the chip holder 100 is now accessible by a pipe 122 for filling the interior 120 with liquid helium. A pipe 124 acts as a vent. A vent such as pipe 124 is usually required for any container intended to hold liquid helium, so as to prevent excessive pressure from building up in the container as the helium boils. Either the washer 106, the cap 82, or the suspension means may be flexible in order to accomodate movement of the substrate The suspension means may also be stretchable. In operation, when it is desired to cool the low temperature circuit on substrate strip 30, the liquid helium is pumped into the interior 120 of the chip holder 100 through pipe 122. The temperature of the circuit can be maintained by pumping additional liquid helium into the interior 120 to replace the helium that boils off. When it is desired to warm the circuit, the helium supply is cut off and the remaining helium is allowed to boil away. No cooling block such as that shown as 12 on FIGS. 1, 2, 3 and 5 is shown in FIG. 6 because its function is accomplished by the cup 108 itself.
FIGS. 7 and 8 show methods which may be used according to the invention to cool the primary cooling surface in the vacuum chamber. They may also be used to cool any surface in a vacuum chamber, whether or not associated with a low temperature circuit. Referring to FIG. 7, a plug assembly 80 comprising a cap 82 and a substrate strip 30 removably plugs a hole 86 in the wall 8 of the vacuum chamber 10 as in previously described embodiments. The low temperature end of the substrate strip 30 is immersed in thermal grease 50 in a cup 108 of a chip holder 100 such as that described with reference to FIG. 5. At least one element is flexible. The bottom of the chip holder 100 is thermally bonded directly to the top of the cooling block 12. The block 12 depends through a wall 150 of a vessel 152 which is disposed inside the vacuum chamber 10. A vertically extending transfer tube 154 having inner and outer coaxial portions 156 and 158, respectively, is attached to the bottom of the vessel 152 and the vacuum chamber 10, such that the inner portion 156 communicates with the inside of the vessel 152 and the outer portion 158 communicates with the vacuum chamber 10. The transfer tube 154 extends down through the mouth of a liquid helium filled dewar 160 which itself has a vacuum chamber 162 for insulation. The bottom of the inner portion 156 of the transfer tube 154 opens into the liquid helium reservoir in the dewar 160, and the bottom of the outer portion 158 is permanently sealed.
In operation, the dewar 160 is pressurized in order to force liquid helium up the inner portion 156 of the transfer tube 154 and into the vessel 152 where it cools the cooling block 12. The vacuum chamber 10 now not only provides an environment in which the chip 30 is mounted, but also provides insulation for the vessel 152 and the transfer tube 154.
The method shown in FIG. 8 is equivalent and somewhat simpler. For variety two plug assemblies 80 are shown rather than one. The copper cooling block 12 is wide enough to provide two sites for the mounting of chips, and it extends downwardly in the shape of a rod 170 into the liquid helium reservoir in the dewar 160. As with the transfer tube 154 of FIG. 7, the vacuum chamber 10 surrounds the rod 170 in an outer coaxial portion 172 which also extends down into the dewar 160. The outer wall of the coaxial portion 172 may also be constructed appropriately to act as a radiation shield. The effect of the apparatus of FIG. 8 is similar to that of FIG. 7, in that heat from the chip mounting sites is removed via thermal communication with a liquid helium reservoir. It is accomplished, however, without the need for a vessel such as 152 or a means for pressurizing the dewar 160.
A monolithic chip which may be used with the present invention will now be described with reference to FIG. 9. It compromises an elongated fused quartz substrate 180, approximately 3 cm long and 0.5 cm wide. A flexible substrate may be used in place of fused quartz if desired, so that the necessity of providing another flexible element in the apparatus to accomodate movement can be avoided. Fabricated at one end of the substrate 180 by a known method is niobium based Josephson Junction circuit 182. Noncritical niobium biasing and monitoring lines 184 connect to the circuit 182 and extend most of the length of the substrate 180 and to a group of connection pads 186. Since high performance is not demanded of the lines 184, the pads may instead be located at the low temperature end of the substrate 180 for bonding to ordinary wires. Two high performance niobium transmission lines 188 and 190 are shown extending from the circuit 182 to the opposite end of the substrate 180 where they may be connected to a room temperature circuit. Since the transmission lines 188 and 190 cannot benefit from superconducting properties, they must be made approximately 1000 um wide in order to maintain the necessary performance. Tapered portions 192 and 194 on transmission lines 188 and 190, respectively, adapt this size to the 2.5 um line widths used in the circuit 182, while maintaining a constant impedance.
In all embodiments described above for the present invention, an object is to achieve the lowest possible temperature for the low temperature circuit, and still permit the use of a high performance transmission line to room temperature. Some low temperature circuits, however, do not require operating temperatures as low as others. For example, a Josephson Junction circuit fabricated with niobium must be operated below the critical temperature of that element of T c =9.2° K. But a Josephson Junction circuit fabricated using niobium nitride may be operated up to its critical temperature of T c =16° K. Other structures which do not depend on superconducting properties such as gallium arsenide may be operated at higher temperatures. Whenever a higher temperature is permissible, the wider operating margins may be used to relax the construction requirements for apparatus according to the invention. For example, different materials which have lower thermal conductivity may be used for thermally connecting the low temperature circuit to the cooling sink. The physical distance of the low temperature circuit from the cooling sink may also be increased. Additionally, other fluids which have higher boiling points but are easier to handle than helium, such as nitrogen, may be used. Where a CCR is used, a less stringent temperature requirement will permit the use of much more easily obtainable, reliable, compact and inexpensive units. Well known thermal conduction principles will aid the designer in choosing among these various options.
It is noted that all drawings attached hereto are schematic in nature and are not intended to convey specific dimensions.
The invention has been described with respect to particular embodiments thereof, and one skilled in the art can now easily ascertain its essential characteristics. Numerous changes and modifications are possible to adapt it to various usages and conditions, all within the scope of the invention. In particular, it is noted that its general principles are applicable to circuits intended to operate at temperatures different than those described above. The circuit inside the vacuum chamber may be intended to operate at low but non-cryogenic temperatures, or even temperatures above room temperature. The circuit located outside the vacuum chamber may also be intended for operation at any desired temperature. Furthermore, both circuits may be located inside the vacuum chamber. The person of ordinary skill in the art can easily adapt the principles of the present invention to these various situations.
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Apparatus is disclosed for electrically interfacing a circuit operable at one temperature with a circuit operable at another temperature, comprising a primary cooling or heating surface disposed inside a vacuum chamber which is thermally connected to the first circuit. Transmission lines may extend through the wall of the vacuum chamber to the second circuit which can be located outside. In one embodiment, the first circuit is operable at cryogenic temperatures and is fabricated on an elongated fused quartz substrate together with the transmission lines. The first circuit may be thermally connected to the primary surface via a secondary surface, which may itself be thermally connected to the primary surface via a flexible support and/or a thermal switch. The use of a flexible element in the construction of the apparatus prevents thermally induced movement from shattering the substrate. The primary surface may be cooled by a thermally conductive rod immersible in liquid helium; by the forced flow of liquid helium into a vessel located inside the vacuum chamber, the interior of which vessel is in thermal communication with the primary surface; by a closed cycle refrigerator; or by other means.
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CROSS REFERENCE TO RELATED APPLICATIONS
Details of the draw bar structure and of the circle mounting bar and circle assembly which are illustrated and described generally in this application are described in detail and claimed in copending U.S. patent applications of Carroll Richard Cole, Ser. No. 661,880 filed Feb. 27, 1976 and Ser. No. 663,594, filed Mar. 3, 1976.
The blade mounting which is illustrated partially in this application is described in detail and claimed in copending U.S. patent application of Carroll Richard Cole, Ser. No. 696,163, filed June 14, 1976.
BACKGROUND OF THE INVENTION
Motor graders have a longitudinal main frame which has a dirigible wheel assembly at its forward end, an operator's cab at its rearward end portion, and a traction chassis for the motor and power train behind the cab. The motor grader blade is suspended from the main frame by means of a circle draw bar and a circle. The circle draw bar has its front end connected to the front of the main frame by a ball and socket connection, while the rearward portion of the circle draw bar is suspended from the main frame by hydraulic cylinder and piston means which permit the draw bar to swing in a vertical plane about its front end.
The circle is mounted on the rearward portion of the circle draw bar for rotation about a vertical axis, and there is a driving interconnection between a motor on the circle draw bar and a ring gear on the circle to effect such rotary motion of the circle.
The grader blade is mounted upon the circle so that rotation of the circle changes the angle of the blade with reference to the path of travel of the grader, while swinging the circle draw bar in a vertical plane about its forward end changes the vertical position of the grader blade with reference to the ground.
In addition, the grader blade is mounted on a horizontal axis so that it may be tipped with respect to the circle by hydraulic cylinder and piston means to change the angle of attack of the blade and it may also be shifted endwise in its mounting.
The hydraulic cylinder and piston units which have heretofore been used to control the tilt of the grader blade assembly have been subject to damage from masses of earth and rocks pushed up by the grader blade moldboard. In addition, the necessity for connecting the cylinder of a hydraulic cylinder and piston unit to the circle with the rod connected to the blade carrying means requires that the head end of the cylinder be mounted to pivot about a transverse axis, and elimination of excessively close manufacturing tolerances for such heavy equipment make it highly desirable that the head end of the cylinder be rotatable about an upright axis as well. However, double trunnion mountings are quite large and clumsy, and cannot be adequately protected against damage from dirt and dust in the very difficult environment in which such hydraulic cylinder units are used.
Typical mountings of hydraulic cylinder and piston units in heavy earth moving equipment are disclosed in U.S. Pat. Nos. 3,311,026, 3,521,782 and 3,631,930. Also of interest are U.S. Pat. Nos. 3,147,671 and 3,683,754.
SUMMARY OF THE INVENTION
The principal object of the present invention is to provide an improved mounting for the hydraulic cylinder and piston units which control the tilt of the blade carrying means of a motor grader.
Another object of the invention is to provide a ball and socket type of mounting for a cylinder and piston unit which is readily assembled and disassembled, and which removably mounts in a protective sleeve which provides the support for the cylinder and piston unit on the motor grader circle.
Still another object of the invention is to provide a mounting for a tilt cylinder and piston unit of a motor grader which affords limited universal movement of the unit and which is also substantially completely sealed against dirt and dust.
THE DRAWINGS
FIG. 1 is a side elevational view of a motor grader embodying the invention;
FIG. 2 is a perspective view of a subassembly consisting of a circle mounting bar, a circle, and a grader blade assembly and improved grader blade support and tilt control means which embodies the present invention;
FIG. 3 is a fragmentary sectional view on an enlarged scale taken substantially as indicated along the line III--III of FIG. 2;
FIG. 4 is a central vertical longitudinal sectional view showing the head end portion of the hydraulic cylinder and piston unit and the details of a first embodiment of the mounting of the cylinder and piston unit;
FIG. 5 is a fragmentary sectional view taken substantially as indicated along the line V--V of FIG. 4; and
FIG. 6 is a view like FIG. 4 on a reduced scale, of a second embodiment of the mounting structure.
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1 of the drawings, a motor grader, indicated generally at 10, includes a longitudinal main frame 11 the front end 11a of which is supported upon a dirigible front wheel assembly 12, and the rear end of which constitutes part of a traction chassis, indicated generally at 13, on which is mounted a power plant, indicated generally at 14. An operator's cab, indicated generally at 15, is on the rear portion of the main frame, forward of the traction chassis. A grader blade subassembly, indicated generally at 16, consists generally of a circle mounting bar, indicated generally at 17, which in the illustrated apparatus is a draw bar; a circle structure, indicated generally at 18; and a grader blade and blade mounting indicated generally at 19.
The circle draw bar 17 is best seen in FIG. 2 to include a forward beam, indicated generally at 20, and a rearward circle carrying structure, indicated generally at 21, the forward part 22 of which is integral with the rear end of the beam 20. Behind the part 22 of the carrying structure said carrying portion has a section 23 the depth of which is great enough that it forms a housing extending below the circle 18. The housing section 23 receives drive means, indicated generally at 24. The housing section 23 of the circle draw bar merges into a nearly semi-annular upright wall 25 which is part of an internal housing for the circle 18, and integral with the wall 25 is a horizontal top wall 26.
The subassembly 16 is mounted under the main frame 11 by means of a front mounting element and rear mounting elements which engage with cooperating elements carried upon the main frame. At the front end 20a of the circle draw bar is a ball 28 which forms part of a ball and socket connection (not shown) by means of which the front of the circle draw bar is connected for universal movement on the front end 11a of the main frame. At the back end of the housing section 23 of the rearward circle draw bar portion 21 is a pair of aligned, laterally extending upright plates 29 which are provided with balls 30 that make ball and socket connections with fittings (not shown) on the lower ends of a pair of hydraulic cylinder and piston units 30a which are carried upon the main frame 11. Thus, operation of the hydraulic cylinder units 30a swings the circle draw bar 17 about the ball and socket connection including the ball 28, which in this respect provides a horizontal pivot axis. A ball 30b on one of the webs 29 provides for a ball and socket connection with a side-shift cylinder (not shown) which shifts the draw bar sideways, with the ball 28 providing a vertical pivot axis.
The grader blade and blade mounting 19 includes a grader blade assembly, indicated generally at 31, which is carried upon blade support arms 32 that are integral with the rear portion of the circle structure 18, and there being blade support means consisting of bearing housings, such as the housing 33, which are mounted on transverse pivots on the arms 32. Each of the bearing housings 33 has a forwardly open lower jaw (not shown) and a forwardly open upper jaw 36 in which a lower blade support rail 37 and an upper blade support rail 38 are respectively mounted for longitudinal sliding movement; and the tilt of the bearing housings 33 about their pivots is controlled by a pair of hydraulic cylinder and piston units, indicated generally at 39.
The hydraulic cylinder and piston units 39 are mounted between the arms 32 in sleeves 42 which are formed integrally with the arms 32 and have their longitudinal axes aligned with portions 44 of the bearing housings 33 which are positioned laterally inwardly from and immediately alongside the arms 32. Each of the hydraulic cylinder and piston units 39 has a cylinder 45 which has a head end 46 and a rod end 47, and a piston with a piston rod 48 which pivotally connects to a transverse pivot pin 49 which is mounted between a pair of webs 50 at the upper, rear end of said bearing housing portion 44.
Referring now to FIG. 4, each of the sleeves 42 has one side defined by the laterally inward surface of the arm 32, and has the remainder of its perimeter defined by a sleeve wall 51 which is a segment of a cylinder. The sleeve wall 51 and a portion of the arm 32 provide a planar rear end 52 which is provided with a circle of spaced, tapped blind bores 53; and the interior of the sleeve wall 51 is provided with a circumferential shoulder 54. The cylinder and piston unit 39 is mounted for limited universal movement in the sleeve 42 by means of a ball and socket structure, indicated generally at 55. The ball and socket structure 55 includes a spherical bearing, indicated generally at 56, which is mounted upon the cylinder 45 of the unit 39; and a socket assembly, indicated generally at 57, which is mounted in the sleeve 42 and carries the spherical bearing 56.
The socket structure 57 consists of a forward annular member 57a which has a forward shoulder 58 that abuts the internal shoulder 54 on the sleeve; and a rearward annular member 57b which has an external rear flange 59 that overlies the annular rear face 52 of the sleeve 42 so that the rear annular socket element 57b may be secured to the sleeve by means of machine screws 60 which screw into the threaded blind bores 53. In order that the two annular parts 57a and 57b of the socket 57 may be properly related to the spherical bearing member 56, annular shims 61 are inserted between the annular end 52 of the sleeve 42 and the forward face of the flange 59.
The spherical bearing 56 is carried upon the cylinder 45 on a collar 62 which is welded to the cylinder and is provided with a forward annular flange 63. At the rear of the collar 62 is a circumferential groove 64 which receives a rearward annular flange 65. The rearward annular flange comprises two identical semi-annular members each of which has a first radially extending web 66 and a second longitudinally extending web 67, and the two semi-annular members are assembled upon the collar 62 in the groove 64 by means of a split ring 68 which surrounds the longitudinally extending web 67 and snaps into aligned circumferential grooves 69 in said web 67.
The universal mounting 55 is protected against dust and dirt by a first flexible annular boot 70 and a second flexible annular boot 71 which are mounted, respectively, at the front and at the rear of the ball and socket means 55.
The boot 70 has a longitudinal portion 72 which closely embraces the cylinder 45 and is held in place by a split retaining ring 73, and the boot has a rearward internal flange 74 which snaps around a forwardly extending annular rib 75 that is formed integrally with the forward socket element 57a.
The second boot has a longitudinal portion 76 which closely embraces the head end 46 of the cylinder 45, and a split ring 77 snaps around the longitudinal portion 76. The second boot 71 also has an internal flange 78 which snaps around a rearwardly extending annular rib 79 which is integral with the flange 59 of the second socket element 57b.
In order to assist in proper orientation of the cylinder and piston unit 39 which it is mounted in the sleeve 42, the forward part of the sleeve is provided with a slot 80 which receives an alignment lug 81 on the cylinder 45. As seen in FIG. 5, there is a rather small clearance between the alignment lug 81 and the slot 80, so that the cylinder and piston unit 39 is held loosely in proper alignment during operation.
Turning now to FIG. 6, the second embodiment of the invention is like the first with the exception that a collar 162 on the cylinder 45 has a fixed circumferential front flange 163 and also has a fixed circumferential rear flange 164. A spherical bearing, indicated generally at 156, consists of two identical semi-annular halves such as the half 156a which is seen in FIG. 6; and said two halves are provided with peripheral grooves 156b which are aligned so as to form a continuous groove extending around the maximum diameter of the spherical bearing 156, and an elastic band 156c encircles the spherical bearing in the groove 156b to keep the two halves assembled during the assembly and mounting of the entire device.
The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.
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A motor grader has a circle which includes integral depending arms at the rear, blade carrying structure is supported forward of the arms on transverse pivots which are at the lower extremities of the arms, and hydraulic cylinder and piston units are supported for limited universal movement in sleeves which are integral with the circle, the pistons of said units being pivotally connected to the blade carrying structure for tilting the latter about the transverse pivots. The cylinder unit supports include flanged collars on the cylinders on which spherical bearings are removably mounted, and bearing sockets in the sleeves consisting of two annular elements which are detachably connected to each other. Flexible dust proofing boots enclose the spherical bearings and sockets; and an interengaging slot and hub restrict rotation of each unit in the sleeve.
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FIELD OF THE INVENTION
[0001] The invention relates to a method and apparatus for assembling a valve spool into a valve body.
BACKGROUND OF THE INVENTION
[0002] Currently, assembling elongated spools into close fitting valve bodies is a manual operation. The reason for this is that clearance between spool lands and bores is 0.0005 inch, the lands and have sharp corners (no lead chamfers), and the bores may not be manufactured to a datum plane. If a bore is machined to a datum plane, then it is a simple matter to orient the bore in a fixture for a later assembly process with the bore oriented in a desired direction, since the orientation of the bore relative to the valve housing is precisely known. If a spool bore is not machined to a datum plane, it is difficult in a the later assembly process to precisely align the machined bore with the insertion tooling for a valve spool so that the spool can be inserted into the bore. Even if a bore is machined to a datum plane, a method is still needed to assist the leading end of the spool to find and enter the land bores in the housing. Currently, there is no reliable method or configuration of tooling that will align spools to bores through which a spool can be dropped into a bore with clearance of 0.0005 inches.
[0003] One technique for facilitating the assembly of a spool into a valve bore uses an air bearing as shown in U.S. Pat. No. 5,829,134 for a Spool Valve Loading Method and Apparatus. The method and apparatus described therein uses pressurized gas at a first pressure to advance a valve spool into a valve body bore, and at the same time pressurized gas at a second lower pressure is applied to the valve body bore to create a moving cushion of air that opposes the insertion of the valve spool into the valve bore. The cushion of air from the valve body creates an air bearing that centers the spool in the bore so that the spool can be inserted the full length into the bore without hanging up on the lands of the bore.
[0004] The technique described above provides satisfactory results provided the spool bores are machined to a datum plane. If the spool bores are not machined to a datum plane, since the bores cannot be precisely aligned with the insertion tooling for the valve spools, the spools will jam if the valve body is positioned too close to the insertion tooling. As the gap between the valve body and the insertion tooling is increased, the tooling cannot maintain the alignment of the spool to the bores, with the result that the spools will jam as they are inserted into the bores, or the leading end of the spool will contact and rest on the surface around the entrance to the bore.
[0005] For the foregoing reasons, the air bearing technique, by itself, does not work for all combinations of spool lengths and spool land diameters. Additional assembly aids are needed to produce an assembly system that will successfully load spools over 95% of the time. The features described herein provide the compliance needed for the spool to be inserted into the bore in a valve body in an automated assembly operation.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0006] FIG. 1s hows various configurations of a valve spool.
[0007] FIG. 2 shows a valve spool that has been inserted into the large bore of a valve body but not into the land bores.
[0008] FIG. 3 shows a valve spool in an off axis position as it begins to enter the small bore of a valve body.
[0009] FIG. 4 shows a valve spool that has been fully inserted into the small bore of a valve body.
[0010] FIG. 5 shows a valve body mounted on a fixture in a raised position and located below a valve spool insertion tool.
[0011] FIG. 6 shows the motion applied to a fixture by a ball oscillator.
[0012] FIG. 7 shows a valve body mounted on a fixture in a raised position with a spool inserted into the large bore of a valve body.
[0013] FIG. 8 shows a valve body mounted on a fixture moving from a raised position to a lowered position with a spool inserted into the top of the small bore of the valve body.
[0014] FIG. 9 shows a valve body mounted on a fixture in a lowered position with a spool inserted into the small bore of a valve body.
[0015] FIG. 10 shows a valve spool with an extension mounted on one end of the spool.
[0016] FIG. 11 shows a valve spool with an extension mounted on one end of the spool being inserted into a valve body.
BRIEF SUMMARY OF THE INVENTION
[0017] It has been determined that the effects of an air bearing may be augmented in various ways in order to assist in the automated assembly of valve spools into valve bores. Such augmentation may be achieved by agitating the valve spool as it is being lowered into the valve body, increasing the effective length of the valve spool so that the agitation can be applied to the spool when the spool is partially inserted into the body, agitating the fixture that supports the valve body, and altering the position of the valve spool relative to the agitation source so that the agitation will have a greater effect on the spool.
[0018] A spool is dropped into insertion tooling positioned directly above the valve body. The insertion tooling allows the spool to fall through a nozzle aligned with the bore in the valve body. Near the outlet of the nozzle, small holes are drilled around the circumference of the nozzle. As the spool falls through the nozzle, air is sequentially introduced into the holes. The pulsating air creates an air vortex and causes the top of the spool to move in an irregular pattern. The resulting motion of the spool permits the spool to “oscillate” and eventually find the hole in the small bore of the valve body. The continued application of the air vortex as the spool descends into the valve body tends to push on the spool from the top, oscillating the spool until it clears the nozzle and is fully inserted into the bore.
[0019] To increase the effective length of short spools and expose more area of the spool to the air vortex, a spring or removable extension is mounted on the shaft on the top end of the spool. The combined length of the valve spool plus the extension helps to maintain the perpendicularity of the spool during the drop into the valve bore and provides additional surface area to receive the pulsating air.
[0020] A pneumatic ball oscillator attached to the fixture provides a smooth oscillation motion to the fixture at a sufficient frequency to cause the lower end of the spool that is confined in the bore to move off of any point of rest between the spool and the bore. The ball oscillator provides a smooth, cycloidal type of movement to the fixture. The cycloidal movement of the ball oscillator induces sufficient movement to the valve body and prevents the spool from maintaining one angular position in, or resting within the confinement of, the bore. The oscillator can be set to vibrate differently for each different spool configuration.
[0021] A variable position fixture may also be used to hold the valve body. Depending on spool length and the number of and diameter of spool lands, one position of the fixture may not be sufficient for the air bearing or vortex to move and oscillate the spool. A servo controlled vertical slide allows the position of the of the valve body to be set for various spool lengths and configurations. After the spool falls into the large bore of the valve body, the bottom end of the spool may come to rest on a surface. Unless the spool end is moved off this surface, it will not drop into the valve bore. If the pulsating air in the nozzle of the insertion tooling is not directly opposite a spool land, the effects of the air vortex on the spool may be minimal. Varying the distance between the valve body and the insertion tooling allows the pulsating air to be directed against the spool at many positions along the spool. As a result, the spool tends go through a series of stop and start movements as it passes the pulsating air in the nozzle.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Turning now to the drawing figures, FIG. 1 shows two forms of valve spools 10 and 10 a . Each of the valve spools comprises an elongated shaft 11 and 11 a on which are positioned a plurality of valve lands 12 and 12 a . The valve lands each have a diameter that is larger than the diameter of the elongated shaft on which they are mounted. The valve lands 12 and 12 a have various axial lengths depending on the configuration of the valve bodies into which they will be mounted. Such valve spools are well known in the art.
[0023] FIG. 2 shows a valve spool partially inserted into a valve body 15 . The valve body 15 is formed with a large upper bore 16 and a lower smaller bore 18 having a smaller diameter than the diameter of the upper bore 16 . The lower bore 18 forms the valve portion of the valve body, and the lower bore includes a number of lands 19 . The lands on the valve body fit closely around the lands 12 formed on the valve spool. The clearance between the spool lands and the valve lands is typically 0.0005 inches. Such valve spools are typically used in transmission assemblies, but may be used in any device in which spool valves are employed.
[0024] FIG. 3 shows a valve spool that is in a jam position as a result of being angularly misaligned with the axis of the valve bore 18 . The axis 21 of the valve spool 10 is not exactly aligned with the axis of the bore 23 of the valve body 15 . As a result of the misalignment, the lowermost land 12 on the spool is jammed against the upper land 25 formed in the valve body that surrounds the entrance to the small bore 18 .
[0025] FIG. 4 shows a valve spool 10 that is fully inserted into a spool valve body 15 . Although some of the lands 12 on the valve spool are shown as being aligned with lands 27 on the valve body, the alignment of the lands of the valve spool and body is not necessary for the valve spool to be full inserted in to the valve body 15 . What is necessary is that the axis 21 of the valve spool becomes perfectly aligned, for a short period of time with the axis 23 of the bore in the spool valve body. Once the spool enters the bore, the oscillation and gravity cause it to fall to the bottom of the bore as more fully explained below.
[0026] FIG. 5 shows a preferred embodiment of the assembly apparatus in which a fixture 30 is attached to a vertically driven servo slide 31 that is in the up position. The valve body 15 is releasably mounted on the fixture 30 . The servo slide 31 is mounted for controlled motion in a direction that is approximately parallel to the bore axis 23 of the valve body 15 . The motion of the servo slide 31 is only approximately parallel to the bore axis 23 since the bore 18 in the valve body may not have been machined to a datum plane, and as a result, it is impossible to mount the valve body and the fixture on the servo slide so that the bore axis 23 is exactly vertical. In the embodiment that is shown, the servo slide is mounted for vertical motion. The motion of the servo slide 31 is controlled by a servo controller (not shown) and the servo slide is mounted on a slide mechanism such as rails (not shown) as well known in the art. The servo slide 31 may be driven by a mechanism that is electromagnetic, mechanical, pneumatic, or hydraulic in nature, as well known in the art. The servo slide includes an inlet 33 that is coupled to a passageway 34 in the fixture for air that is blown into the valve bore 18 in order to form an air bearing as described in U.S. Pat. No. 5,829,134 described above. With the servo slide in this position, the air bearing air admitted into the valve bore 18 is on. The servo slide 31 allows the valve body 15 to be positioned relative to the insertion tooling 41 described below so that the air bearing has the desired effect.
[0027] A ball oscillator 35 is mounted on the lower portion of the fixture 30 . The ball oscillator provides a smooth cycloidal oscillation motion to the fixture 30 at a sufficient frequency to cause the lower end of the spool 10 that is confined in the bore to move off of any point of rest. Depending on the angular mounting position of the oscillator, the fixture movement can be from 0.000 to 0.002 inch in any direction. Normally, it is from 0.000 to 0.002 inch in any of the three major axis, X, Y and Z. The cycloidal movement of the ball oscillator 35 induces sufficient oscillation in the valve body 15 to prevent the spool 10 from maintaining one angular position and or resting within the confinement of the bores 16 and 18 . The oscillator can be controlled to produce a different oscillation, frequency or amplitude, for each different spool configuration. In the preferred embodiment, the ball oscillator 35 is pneumatic ball rotary device, but other types of oscillators may be used.
[0028] FIG. 6 shows the motion imparted to the fixture 30 and the valve body 15 by the ball oscillator 35 . Accordingly, the fixture and the valve body may be moved 0.000 inch to 0.002 inch in any direction.
[0029] Returning to FIG. 5 , directly above the valve body 15 is a spool insertion tool 41 mounted on a tooling support 42 . The insertion tool 41 is an elongated hollow body having an axial bore 43 slightly larger that the diameter of the spool lands that will be inserted by the insertion tool. The axial bore 43 has a center axis 45 . The insertion tool 41 is formed with a mounting ring 44 on its outer surface. A mounting plate 46 is attached to the underside of the tooling support 42 by suitable fasteners 47 . The mounting plate 46 is formed with a recess 48 to receive the mounting ring 44 and to secure the insertion tool to the tooling support. The insertion tooling 41 may be attached to the tooling support 42 in ways other than as shown as will be appreciated by those skilled in the art.
[0030] A flared opening 51 is formed on the upper portion of the axial bore 43 of the insertion tool 41 to allow the valve spool to be funneled into the insertion tool without becoming jammed on the top opening of the axial bore. The lower end of the axial bore is formed with a nozzle 53 . A plurality of holes 54 is formed around the circumference of the nozzle 53 . In the preferred embodiment, four holes 54 are equally spaced around the circumference of the nozzle, and are preferably about ⅛ inch in diameter, but other arrangements, numbers and sizes of holes may be used. The holes 54 are formed so that the axis of the holes intersects with the axis 45 of the insertion tooling. The holes may be formed at other angular orientations. Inlet fittings 57 are mounted in each of the holes 54 , and air supply lines 58 are attached one each to the inlet fittings. The air supply lines 58 are coupled to an air controller 59 . The air controller 59 controls the admission of air through the air supply lines 58 to the four holes formed in the nozzle 53 of the insertion tooling. In the preferred embodiment, the air controller 59 causes air to be sequentially introduced into the holes 54 . The pulsating air creates an air vortex in the insertion tooling nozzle 53 , and causes the top of the spool 10 to move in an irregular pattern as the spool falls through the nozzle 53 . The air controller 59 delivers air to air supply lines at a pressures from 15 to 60 pounds per square inch. Although the nozzle is shown formed on the end of the insertion tooling 41 , the nozzle could also be formed as a separate stand alone unit positioned between the insertion tooling and the valve body 15 .
[0031] FIG. 5 additionally shows an escapement slide 64 mounted above the tooling support 42 and a valve spool 10 in the escapement slide. The escapement slide 64 is shown ready to move to the right to drop the spool 10 into the insertion tool 41 . The escapement slide 64 comprises an elongated hollow holder that is dimensioned to receive a valve spool. The position of the escapement slide is controlled by a suitable mechanism that moves the slide back and forth from the position shown where it is adjacent to the opening of the insertion tool 41 to a position shown in phantom where is directly over the insertion tool 41 . When it is directly over the insertion tool, the valve spool 10 will be in alignment with the axis 45 of the insertion tool and the axis 23 of the valve body.
[0032] FIG. 7 shows the valve spool 10 as it is being inserted into the top of the valve body 15 . The servo slide 31 and the fixture 30 are shown in the up position. The air bearing air applied to the inlet 33 is on. The spool 10 has moved to the drop position, and the spool has entered the large bore 16 of the valve body 15 . The vortex air applied to the inlets 57 is turned on during the drop of the spool, and the ball oscillator 35 is turned on. The valve spool 10 is in alignment with the axis 23 of the bore of the valve body. The air controller 59 applies air sequentially to the air inlets 57 so that an air vortex is created in the insertion tooling nozzle 53 . This allows the spool 10 to oscillate laterally as it lowers into the valve body 15 . The pulsating air causes movement of the spool in an irregular pattern and the lower end of the spool will “hunt” until the lowermost land 12 on the spool is exactly aligned with the upper land 19 of the valve body. When the exact alignment occurs, the spool will drop into the lower bore 18 of the valve body.
[0033] FIG. 8 shows the valve spool 10 as the lowermost land 12 on the spool enters the upper land 19 on the valve body. The air bearing air applied to the air inlet 33 is on. The air vortex air applied to the nozzle inlets 57 is on. The servo slide 31 with the fixture 30 is slowly moving down to allow for the maximum effect of the air vortex on the spool 10 as the lowering spool allows the vortex air to impact on both the shaft 11 and the lands 12 of the spool. The rate of descent of the servo slide 31 may be varied until the best results for each different valve and spool configuration are determined by trial and error. The typical rate of descent for the servo slide 31 is one-half inch per second. Depending on spool configuration, this speed may vary. Most spool configurations do not require fixture movement during insertion. One position of the fixture relative to the nozzle is sufficient for most spools to find and drop into their respective bores. The ball oscillator 35 is on to prevent the spool from resting in one place in the valve bore.
[0034] The application of the vortex air to the nozzle 53 of the insertion tool 41 will cause the spool to vibrate slightly as it falls by gravity into the valve body 15 . At the same time, as the spool lowers further into the valve body, the vortex air introduced into the insertion nozzle tends to push on the top of the spool 10 in addition to oscillating the spool until the spool completely clears the insertion nozzle 53 and is lowered into final position in the valve body 15 .
[0035] FIG. 9 shows the servo slide 31 and the fixture 30 in the down position. The air bearing air applied to the inlet 33 , the vortex air applied to the air inlets 57 , and the ball oscillator 35 are all off. The spool 10 is in the fully inserted position in the spool valve housing 15 .
[0036] Automated inspection for the presence of a spool “out of position” may be performed by optical sensors, not shown, positioned at the top of the valve body 15 . If a spool fails to fall below the top surface of the valve body 15 , the sensor will detect this condition and stop the automated assembly process. Such automated inspection processes and the apparatus therefor are well known to those skilled in the art.
[0037] FIG. 10 shows a short length spool 70 with one large land 71 near the top. The shape and mass distribution of spool 70 makes it unstable as it falls into the bore of a valve body. The length of the land 71 is not sufficient to maintain perpendicularity between the spool and the bore 18 as the spool falls into the bore. The bottom end 73 of the spool tends to catch on the surface 25 at the entrance of the small bore 18 as shown in FIG. 3 , and the spool lies to one side. In this cocked position, the top of a short spool is below the injection tooling nozzle 53 , and as a result, the air vortex in the nozzle has no effect on the spool.
[0038] The effective length of a short spool 70 may be increased by mounting a removable extension such as a spring 72 on the upper end 74 of the spool. The inner diameter of the removable extension 72 is chosen so that it is a slip fit over the outer diameter of end 74 of the spool on which it will be mounted. Once the extension 72 has been mounted on the spool 70 , the spool is loaded into the escapement slide 64 in the usual way. The escapement slide is moved into position over the insertion tooling so that the spool with the extension mounted thereon can drop into the insertion tooling 41 .
[0039] FIG. 11 shows the spool 70 with a spring 72 mounted thereon as the spool enters the lower portion of the valve body. Although the top end 74 of the spool has passed through the nozzle 53 , the upper portion of the spring 72 is still contained within the nozzle. The upper portion of spring 72 presents a surface against which the vortex air can act, and as a result, the vortex air can continue to produce oscillations in the spool 70 after the spool itself has dropped below the insertion tooling nozzle 53 . After assembly of the spool into the valve body 15 , the extension is removed.
[0040] Although the extension has been described as a removable spring, the spring does not have to be removable, and other forms of extension device may be used. For example, if the valve spool when assembled into the valve body includes a spring on the top end of the valve for operational purposes, the spool with the spring attached may be assembled into the valve body as a subassembly. In this situation, the spring is not removed after the spool has been inserted into the valve body. In another example, the extension may comprise a length of tubing that fits over the top end 74 of the spool. The tubing may be formed of metal, nylon or rubber, or other hollow material that may be slip fit over the top end of the spool.
[0041] Although the invention has been described in the environment valve spools used in automatic transmission assemblies, the spool assembly technique described herein can be used for assembling any elongated valve spool into a tight fitting bore. Such constructions may be used on hydraulic valves, pneumatic valves, or other similar configurations in a variety of valve applications.
[0042] Having thus described the invention, various modifications and alterations will occur to those skilled in the art, which modifications and alterations are intended to be within the scope of the invention as defined by the appended claims.
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The effects of an air bearing may be augmented in various ways in order to assist in the automated assembly of valve spools into valve bores. Such augmentation may be achieved by agitating one end of the valve spool with sequentially applied pulses of pressurized air as the spool is being lowered into the valve body, increasing the effective length of the valve spool so that the agitation can be applied to the spool when the spool is partially inserted into the body, varying the position of the valve spool while the spool is being inserted into the valve body to expose a length of the spool to the pulses of pressurized air, and applying an oscillating vibration to the fixture that supports the valve body to dislodge a spool that has become jammed in the valve bore.
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BACKGROUND OF THE INVENTION
The present invention relates to ink jet recording apparatuses and particularly to ink jet recording apparatuses using ultraviolet ray hardening type inks.
Conventionally, compared to the gravure printing method and the flexo-graphic printing method, ink jet recording apparatuses have come to be used widely because it is possible to reduce the cost when carrying out small-lot printing jobs since no plate making process is necessary, because it is possible to print on various types and sizes of recording media, and because images equal in quality to silver halide photographs, and other reasons.
In recent years, in such ink jet recording apparatuses, ultraviolet ray hardening type inks such as radical polymerization type inks or cation polymerization type inks are being used because it is possible to print on various types of printing media using such ink jet apparatuses, and several recording heads of each color have come to be arranged in ink jet recording apparatuses in order to carry out high quality and high speed printing on still wider range of types of recording media.
However, when recording is done using plural recording heads, there is the problem that ink clogging occurs in the nozzles of the recording heads due to ink remaining in the recording head or due to paper dust or paper waste accumulated near the nozzles, thereby causing degradation of the image quality due to ink dot dropouts.
In view of this, as is indicated in Patent Document 1, there have been proposals to provide maintenance apparatuses in ink jet recording apparatuses to carry out maintenance of the recording heads. In the maintenance head of such a maintenance apparatus, the cap bases (which are coupling sections) for carrying out the maintenance tasks of suctioning the ink in the recording heads of each color are arranged to correspond to the recording heads of different colors that are arranged in a zigzag manner while being adjacent to each other. Thus, deterioration in the recorded image quality is attempted to be prevented by preventing nozzle clogging by carrying out maintenance of all the plural recording heads using this maintenance apparatus.
Patent Document 1: Japanese Patent Application Laid Open No. 2003-127407
However, as is indicated in Patent Document 1, there is the problem that arranging the same number of maintenance units in the maintenance apparatus as the number of recording heads not only increases the manufacturing cost but also makes the maintenance apparatus very large in an ink jet recording apparatus requiring a large number of recording heads.
Further, in the conventional maintenance apparatuses, since no cover for preventing exposure to ultraviolet rays from the ultraviolet ray irradiating apparatus had been provided and since light shut off measures were insufficient, the ink remaining in or the ink adhering to the cap bases become hardened due to the ultraviolet ray irradiation during the operation of the ink jet recording apparatus or due to the ultraviolet rays in the ambient natural light, particularly in the case of ultraviolet ray hardening cation type inks that are more susceptible to accumulate optical activation energies. Because of this, there was the problem that it is not possible to carry out thoroughly the maintenance operations such as suction using cap bases etc., thereby leading to defects of the ink jet recording apparatus.
SUMMARY OF THE INVENTION
The present invention has been made considering the aspects described above, and the purpose of the present invention is to provide an ink jet recording apparatus in which it is possible to carry out maintenance thoroughly even when image recording at high speeds and high image qualities is made and in which not only the manufacturing cost of the maintenance apparatus is lowered but also the size of the maintenance apparatus is made small. The above-mentioned object is attained by any one of the structures stated below.
Structure 1
In order to solve the above problems, the present invention proposes an ink jet recording apparatus with the feature that, in an ink jet recording apparatus comprising a recording head of the ink jet type in which ink hardening upon irradiation with ultraviolet rays is ejected, and an ultraviolet ray irradiation apparatus for hardening the ink ejected from said recording head; a maintenance apparatus is provided comprising a maintenance unit for carrying out maintenance of said recording head and a maintenance unit cover that covers said maintenance unit, with said maintenance unit cover having an opening section for making a cap base (which is a coupling section) provided in said maintenance unit to project beyond said maintenance unit cover and to come into close contact with said recording head, and with said opening section being provided with a light shutter plate for shutting off said cap base from the ultraviolet rays emerging from said ultraviolet ray irradiation apparatus.
According to the present invention described in Structure 1, in said maintenance apparatus, because said maintenance unit cover not only has an opening section for making said cap base provided in said maintenance unit to project beyond said maintenance unit cover and to come into close contact with said recording head but also because said opening section is provided with a light shutter plate for shutting off said cap base from the ultraviolet rays emerging from said ultraviolet ray irradiation apparatus, it is possible to shut off the ultraviolet rays from illuminating said cap base.
Structure 2
The invention according to Structure 2 has the feature that in said ink jet recording apparatus described in Structure 1 above, said control apparatus is provided that executes the control of making the maintenance of said recording heads to be carried out by moving said maintenance unit of said maintenance apparatus during maintenance to said opening section.
According to the invention described in Structure 2, because said control apparatus is provided that executes the control of making the maintenance of said recording heads to be carried out by moving said maintenance unit of said maintenance apparatus during maintenance to said opening section, not only the ultraviolet light illuminating said cap base is shut off but also it is possible to carry out maintenance using lesser number of maintenance units than the number of said recording heads.
Structure 3
The invention according to Structure 3 has the feature that in said ink jet recording apparatus described in Structure 1 or Structure 2 above, said maintenance unit cover is provided with said light shut off plate that covers a top surface of said cap base (which is a coupling section).
According to the invention described in Structure 3, in said ink jet recording apparatus, because said light shut off plate is provided so as to cover a top surface of said cap base, it is possible to shut off ultraviolet rays from said ultraviolet ray irradiation apparatus of said ink jet recording apparatus or from natural ambient light from impinging on the ink remaining or adhering to said cap base at all times except during maintenance.
Structure 4
The invention according to Structure 4 has the feature that, in said ink jet recording apparatus described in Structure 3 above, said light shut off plate is formed with larger dimensions than the height and width dimensions of said cap base.
According to the invention described in Structure 4, in said ink jet recording apparatus, because said light shut off plate is formed with larger dimensions than the height and width dimensions of said cap base, it is possible to shut off the ultraviolet rays impinging through said opening section, and, in particular, in said ink jet recording apparatus using ultraviolet ray hardening type of inks, it is possible to shut off the ultraviolet rays radiated from said ultraviolet ray irradiation apparatus from impinging on said cap base.
Structure 5
The invention according to Structure 5 has the feature that, in said ink jet recording apparatus described in any one of Structure 1 to Structure 4 above, said recording head comprises three recording heads arranged in a zigzag manner along the vertical scanning direction Y.
According to the invention described in Structure 5, in said ink jet recording apparatus, it is possible to carry out maintenance with fewer number of said maintenance units compared to the case in which the number of maintenance units would increase due to said maintenance units also being arranged in a zigzag manner corresponding to said recording head having a configuration in which three recording heads are arranged in a zigzag manner along the vertical scanning direction Y.
Structure 6
The invention according to Structure 6 has the feature that, in said ink jet recording apparatus described in any one of Structure 1 to Structure 5 above, an O-ring (which is a sealing member) is provided in said cap base for making said cap base come into close contact with said recording head, and that the material used for said O-ring is perfluoro-elastomer.
According to the invention described in Structure 6, because said O-ring is provided in said cap base of said maintenance unit for making said cap base come into close contact with said recording head, and because the material used for said O-ring is perfluoro-elastomer, not only the replacement becomes easy but also durability over long periods can be obtained without any dissolving, bloating up or becoming slippery due to the chemical constituents contained in the ink.
Structure 7
The invention according to Structure 7 has the feature that, in said ink jet recording apparatus described in any one of Structure 1 to Structure 6 above, said ink used is one having a viscosity of 10 to 50 mPa·s and a surface tension of 20 to 40 mN/m at 25° C.
According to the invention described in Structure 7, in said ink jet recording apparatus, it is possible to use inks having a viscosity of 10 to 50 mPa·s and a surface tension of 20 to 40 mN/m at 25° C.
Structure 8
The invention according to Structure 8 has the feature that, in said ink jet recording apparatus described in any one of Structure 1 to Structure 7 above, said ink used is of the ultraviolet ray hardening type.
According to the invention described in Structure 8, in said ink jet recording apparatus, it is possible to use inks of the ultraviolet ray hardening type.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 . A perspective view of the ink jet recording apparatus according to the present invention.
FIG. 2 . A perspective view of the interior of the maintenance apparatus according to the present invention.
FIG. 3 . A perspective view of the maintenance mechanism of the cap base of the maintenance unit according to the present invention.
FIG. 4 . A perspective external view when the maintenance unit is stored in the maintenance apparatus according to the present invention.
FIG. 5 . A perspective external view of the maintenance according to the present invention during maintenance.
FIG. 6 . A perspective side view when the maintenance unit is stored in the maintenance apparatus according to the present invention.
FIGS. 7 ( a ), ( b ) ( c ) and ( d ). An example of the light shutting off plate according to the present invention.
FIG. 8 . The outline diagram of the maintenance process according to the present invention at the time of starting and stopping.
FIG. 9 . The outline diagram of the maintenance process of the first row of recording heads according to the present invention.
FIG. 10 . The outline diagram of the maintenance process of the second row of recording heads according to the present invention.
FIG. 11 . The outline diagram of the maintenance process of the third row of recording heads according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the ink jet recording apparatus according to the present invention is described below referring to FIG. 1 to FIG. 11 . However, the following is merely one example of the preferred embodiments of the present invention and the descriptions given here are not to be construed to limit the scope and intent of the present invention to this example in any manner.
FIG. 1 is a perspective view of the ink jet recording apparatus according to the present preferred embodiment. Said ink jet recording apparatus is provided with a printer main unit 1 and a supporting table 2 that supports the printer main unit 1 . The rod shaped guide rail 3 is provided in the printer main unit 1 , and the carriage 4 is supported by this guide rail. This carriage 4 is made to carry out reciprocating movement in the horizontal scanning direction X along the guide rail 3 by a drive mechanism not shown in the figure.
As is shown in FIG. 1 and FIG. 8 , the carriage 4 has mounted on it the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K, having ejection outlets for ejecting inks of each of the colors yellow (Y), magenta (M), cyan (C), and black (K). Three recording heads for each color in these recording heads are arranged in a zigzag manner in a direction (vertical scanning direction Y) at right angles to the horizontal scanning direction X. Each of said recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K are connected respectively to ink tanks (not shown in the figure) that store inks of each of the colors yellow (Y), magenta (M), cyan (C), and black (K).
Further, ultraviolet ray irradiation apparatuses 8 that radiate ultraviolet rays towards the ink ejected from the ejection outlet onto the recording medium are provided on both sides of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K, along the horizontal scanning direction X of the carriage 4 .
Further, a transport mechanism (not shown in the figure) that feeds the recording medium along the vertical scanning direction Y is provided on the printer main unit 1 . The transport mechanism is provided with, for example, a transport motor not shown in the figure and transport rollers etc, and the recording medium is transported along the vertical scanning direction Y by rotating the transport rollers by driving the transport motor. Further, the transport mechanism, during image recording, transports the recording medium intermittently by repeating transportation and stopping of the recording medium, coordinating with the operation of the carriage.
In addition, a flat plate shaped platen 9 that supports the recording medium from the non-recording surface is provided in the lower recording area of the carriage 4 .
A home area for holding the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K, mounted on the carriage 4 in the standby state is provided at one end of the movement area of the carriage 4 of said inkjet recording apparatus.
A maintenance area for carrying out the maintenance of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K mounted on the carriage 4 is provided at the other end of the movement area of the carriage 4 of said ink jet recording apparatus. A maintenance apparatus 11 for carrying out maintenance for each color of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K, of the carriage 4 is provided in said maintenance area of said ink jet recording apparatus.
As is shown in FIG. 2 , said maintenance apparatus 11 is provided with four maintenance units arranged along the horizontal scanning direction X so as to correspond to the recording heads of each of the colors Y, M, C, and K, and is also provided with a unit transporting table 12 that not only supports each of said maintenance units but also carries out their reciprocating movement along the vertical scanning direction Y.
This unit transporting table 12 is configured so that it is free to move in the vertical scanning direction Y along a rail not shown in the figure, and a transport mechanism not shown in the figure is provided in this unit transporting table 12 . This transport mechanism is configured, for example, to comprise a rack placed along said rail, and a pinion that mates with said rack and whose rotation is driven by a drive motor not shown in the figure but installed on the unit transporting table 12 , and the unit transporting table 12 can be moved in a reciprocating manner along the rail by moving the pinion with respect to the rack by driving the rotation of the pinion using the drive motor.
As is shown in FIG. 2 and FIG. 8 , each maintenance unit comprises the cap base 15 that covers the nozzle surface of the recording heads 5 , 6 , 7 for each color, and a supporting table 13 that supports the cap base 15 . This supporting table 13 is provided with the lift mechanism 14 that raises and lowers the cap base 15 , and the lift mechanism 14 is configured to comprise a lift motor, and an eccentric cam whose rotation is driven by the drive from this lift motor while maintaining contact with the bottom surface of the cap base 15 . Thus, it is possible to carry out the raising and lowering operations (in direction Z) of the cap base 15 by driving the rotation of the eccentric cam using the drive of the lift mechanism 14 .
As is shown in FIG. 3 , the top surface of the cap base 15 is provided with a groove having the shape of a rounded-rectangle, and an O-ring 16 that comes into close contact with the nozzle surface of the recording heads 5 , 6 , 7 at the time of carrying out maintenance has been press-fitted inside this groove. The performance characteristics of this O-ring 16 can be sustained for a long period by selecting its material to have resistance to chemicals, thermal stability, and ability to withstand corrosion, and it is desirable to use for this material a perfluoro-elastomer which does not bloat up or become slippery particularly when it comes into contact with cation polymerization type inks.
Further, a suction hole 21 that sucks ink from the nozzles of the recording heads 5 , 6 , 7 is provided at the center of this groove and a tube 17 is connected to this suction hole 21 . A suction pump (not shown in the figure) is introduced at the middle part of this tube 17 and a waste ink tank (not shown in the figure) that collects the ink sucked by the suction pump is connected to the other end of the tube 17 .
As is shown in FIG. 4 , a maintenance unit cover 18 that shuts out ultraviolet rays emitted from the ultraviolet ray irradiation unit 8 is provided on the outside of the maintenance unit of said maintenance apparatus 11 . The position of the top surface of this maintenance cover unit 18 has been arranged to be lower than the position of the top surface of the platen 9 so that the cap bases 15 , 15 , . . . of the maintenance unit can come into close contact with the nozzle surface of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K. The inner and the outer surfaces of said maintenance unit cover 18 should desirably be coated with black alumite which has low reflectivity for the impinging ultraviolet rays.
As is shown in FIG. 4 and FIG. 5 , four opening sections 19 corresponding to each unit are provided on the top surface of said maintenance unit cover 18 . As is shown in FIG. 5 , the width dimension of each of this opening sections 19 is set so that the cap base 15 of the maintenance unit can pass through it, and the length dimension of the opening section 19 is set so that it corresponds to the overall lengths of each of the recording heads 5 , 6 , 7 arranged along the vertical scanning direction Y. Further, the part of the inner side of the maintenance unit cover in which the opening section 19 has not been formed is taken as the standby position of the maintenance unit, and the maintenance unit is made to standby at a position at which the top surface of the cap base comes close to the inner side of the top surface of the maintenance unit cover. Further, it is desirable that this opening section 19 is formed to have a small size so that the ultraviolet rays from the ultraviolet irradiation apparatus 8 do not impinge on the maintenance unit inside.
As is shown in FIG. 6 , the light shut off plate 20 that shuts off the ultraviolet rays impinging on the cap base 15 is formed by bending at the end on the side of said standby position of the opening section 19 of said maintenance unit cover. This light shut off plate 20 , as is shown in FIG. 6 , has been formed with a specific angle θ with respect to the top surface of the maintenance unit cover so that the ultraviolet rays entering from the opening section do not impinge on the end section of the cap base 15 , and in addition, the light shut off plate 20 is formed to have larger dimensions than the height and width dimensions of the cap base 15 .
Further, although the light shut off plate 20 shown in FIG. 6 is one that has been formed by bending at a rounded angle with respect to the top surface of the maintenance unit cover, it is not necessary to restrict the present invention to this. For example, as is shown in FIG. 7( a ), it is also possible to form this by bending at sharp angles to the top surface of the maintenance unit cover, and it is also possible to form this plate by bending it in two or three stages at its middle part, as shown in FIGS. 7( b ), 7 ( c ) and 7 ( d ).
Next, the control apparatus in the present preferred embodiment is described below.
The control apparatus is provided with an interface, storage devices such as ROM, etc., and a CPU. The drive units of the recording head and the carriage 4 , the ultraviolet ray irradiation apparatus 8 , the lift mechanisms, unit transport mechanisms (not illustrated), and suction pumps (not illustrated) of the maintenance units are all connected to the interface.
Further, the CPU of the control apparatus loads the program that has been stored beforehand in the memory circuits in the work area, and by executing various processes according to the program carries out the controls of the lift mechanisms 14 , transport mechanisms 21 , and suction pumps of the maintenance units 11 , of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K, the drive apparatus of the carriage 4 , the ultraviolet ray irradiation apparatus 8 , etc.
In addition, the inks that can be used in the present preferred embodiment can be any of solvent based inks, water based inks, oil based inks, and photo-hardening type inks, etc. It is preferable that the ink has a viscosity in the range of 10˜50 mPa·s at 25° C. and a surface tension in the range of 20˜40 mN/m in order for the ink to adhere easily to various types of recording media and not to clog the nozzle of the recording heads.
In particular, it is desirable that the ink is of the photo-hardening type that is used with a wide range of recording media. Even among them, it is desirable that the ink contains cation type ink that can accumulate ultraviolet ray activation energy and gets hardened easily because the light shut off effect of said maintenance apparatus 11 is high for ultraviolet rays and the maintenance can be done definitely. In addition, it is also acceptable to use inks that have additives of photoinitiators thereby having become easier to harden.
The recording medium used in the present preferred embodiment can be any of absorbent type media such as ordinary paper, high quality (bond) paper, glossy paper, etc., or non-absorbent type media such as PVC, glass, metal, etc.
Next, the operation of the ink jet recording apparatus according to the present preferred embodiment is described below.
When a specific image information is input to the control apparatus, the control apparatus controls the transporting apparatus transporting the recording medium along the vertical scanning direction Y and positions it over the platen 9 . Next, the inks of different colors are made to be ejected onto the recording medium by operating the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K based on the image information while carrying out reciprocating movement of the carriage 4 along the horizontal scanning direction X using the driving apparatus of the carriage. The ink landing on the recording medium is hardened and fixed by the ultraviolet ray irradiation from the ultraviolet ray irradiation apparatus 8 , thereby recording the desired image on the recording medium.
After a specific number of images have been recorded, in order to avoid deterioration in the image quality such as due to dot dropouts of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K, the maintenance operations are carried out under the control of the control apparatus in order to carry out maintenance of the recording heads.
Next, the maintenance operation of the present preferred embodiment is described below.
When carrying out maintenance, as is shown in FIG. 6 , firstly, the carriage is moved to the maintenance area under the control of the control apparatus, and the nozzle surface of the recording heads 5 Y, 6 Y, 7 Y, 5 M, 6 M, 7 M, 5 C, 6 C, 7 C, and 5 K, 6 K, 7 K is positioned directly above the opening section 19 of the maintenance apparatus 11 . The maintenance unit is lowered (in direction Z) using the lift mechanism 14 to the position at which it does not touch the lower end part of the light shut off plate 20 , and thereafter, it is moved in the vertical scanning direction Y by means of the unit transporting mechanism (which is not illustrated) thereby positioning each cap base directly under the recording heads 5 y , 5 M, 5 C and 5 K.
Thereafter, as is shown in FIG. 9 , the maintenance unit is raised using the lift mechanism 14 so that the O-ring of the cap bases 15 , 15 , . . . gets in close contact with the nozzle surface of the first row of recording heads 5 Y, 5 M, 5 C and 5 K, and the suction pump is operated in this condition thereby suctioning ink from the nozzles of the recording heads 5 Y, 5 M, 5 C and 5 K for a specific period of time. After stopping the suction pump, the maintenance unit is lowered using the lift mechanism 14 so that it gets separated from the first row of recording heads 5 Y, 5 M, 5 C and 5 K.
Next, as is shown in FIG. 10 , the carriage 4 is moved in the horizontal scanning direction X using the drive apparatus of the carriage 4 and is stopped when the second row of recording heads 6 Y, 6 M, 6 C and 6 K is positioned directly above the opening section 19 of the maintenance apparatus 11 . The maintenance unit is then moved using the unit transporting mechanism 21 in the vertical scanning direction Y so that each of the cap bases are positioned directly under the second row of recording heads 6 Y, 6 M 6 C and 6 K. Subsequently, the maintenance operation of the second series of recording heads 6 Y, 6 M, 6 C and 6 K is carried out by the maintenance apparatus 11 by carrying out the maintenance operations similar to the operation described above.
Next, as is shown in FIG. 11 , after the completion of the maintenance of the second series of recording heads 6 Y, 6 M, 6 C and 6 K, again under the control of the control apparatus, the carriage is moved to a position at which the third row of recording heads 7 Y, 7 M, 7 C and 7 K come directly above the opening section 19 , and in this condition, the maintenance operations are made in a manner similar to that described above.
When the maintenance operations for each of the recording heads has been completed, the maintenance unit is lowered using the lift mechanism thereby making the cap bases get separated from the recording heads 7 Y, 7 M, 7 C and 7 K. Thereafter, the maintenance unit is moved to the standby position using the unit transporting mechanism 21 , and using the lift mechanism 14 , it is raised to a position in which the cap bases do not touch the inner side of the top surface of the maintenance unit cover.
After that, the carriage 4 is moved away from the maintenance area and recording of image is done on the next recording medium.
In the above manner, according to the ink jet recording apparatus of the present preferred embodiment, by controlling the maintenance unit using the control apparatus, it is possible to carry out maintenance of three rows of recording heads using only one row of maintenance units. In addition, since the maintenance unit cover 18 is provided in the maintenance apparatus 11 and the light shut off plate 20 is provided in this maintenance unit cover, it is possible to prevent definitely the cap bases 15 from getting exposed to ultraviolet rays emanating from the ultraviolet ray irradiation apparatus 8 and entering through the opening section 19 , thereby making it possible to carry out maintenance operations such as suction by the cap base without hardening, particularly, the cation type inks that either get adhered to or remain on the cap base 15 .
Because of this, even when carrying out high speed and high image quality image recording, it is possible to carry out maintenance of the recording heads positively, and not only the cost of manufacture of the maintenance apparatus is reduced but also the maintenance apparatus can be made smaller in size.
Further, in order to carry out maintenance much faster, it is possible to provide several rows of maintenance units along the horizontal scanning direction X instead of only one row of maintenance units, or else even only one row can also be provided. Further, it is not necessary to restrict to primary colors of K, C, M, and Y, but also the maintenance units can be provided for secondary or ternary colors.
In addition, the transporting mechanism of the maintenance units can be provided for each maintenance unit or for several units.
Furthermore, the time of starting the recording need not be restricted to the number of times of operation of the recording head, but it is possible use an external input from an input apparatus or to provide an apparatus for recognizing the dirtiness of in recording heads, and also, it is possible to carry out maintenance at the time of starting the operations or at the end of operations, etc.
Effects of the Invention
According to the present invention described in Structure 1, in said maintenance apparatus, because said maintenance unit cover not only has an opening section for making said cap base provided in said maintenance unit to project beyond said maintenance unit cover and to come into close contact with said recording head but also because said opening section is provided with a light shutter plate for shutting off said cap base from the ultraviolet rays emerging from said ultraviolet ray irradiation apparatus, it is possible to shut off the ultraviolet rays from illuminating said cap base and hence there is the effect that it is possible to reduce the hardening of ultraviolet ray hardening type inks that have got adhered to or are remaining on the cap base.
According to the invention described in Structure 2, because said control apparatus is provided that executes the control of making the maintenance of said recording heads to be carried out by moving said maintenance unit of said maintenance apparatus during maintenance to said opening section, it is possible to carry out maintenance more efficiently using lesser number of maintenance units and hence there is the effect of reducing the manufacturing cost of the maintenance apparatus and of making the size of the maintenance unit smaller.
According to the invention described in Structure 3, in said ink jet recording apparatus, because said light shut off plate is provided so as to cover the top surface of said cap base, it is possible to shut off ultraviolet rays from said ultraviolet ray irradiation apparatus of said ink jet recording apparatus or from natural ambient light from impinging on the ink remaining or adhering to said cap base at all times except during maintenance, and hence there is the effect that it is easily possible to reduce the hardening of ultraviolet ray hardening type inks that have got adhered, etc., and to carry out the maintenance operation of suction using the cap base definitely.
According to the invention described in Structure 4, in said ink jet recording apparatus, because said light shut off plate is formed with larger dimensions than the height and width dimensions of said cap base, it is possible to shut off the ultraviolet rays impinging through said opening section, and, in particular, in said ink jet recording apparatus using ultraviolet ray hardening type of inks, it is possible to shut off the ultraviolet rays radiated from said ultraviolet ray irradiation apparatus from impinging on said cap base, and hence there is the effect that it is possible to carry out the maintenance operation of suction using the cap base definitely.
According to the invention described in Structure 5, since said recording head has a configuration of three recording heads arranged in a zigzag manner along the vertical scanning direction Y, it is not necessary to arrange the number of maintenance units corresponding to the recording heads in a zigzag manner making it possible to carry out maintenance with fewer number of said maintenance units, and hence there is the effect of reducing the manufacturing cost of the maintenance apparatus and of making the size of the maintenance unit smaller.
According to the invention described in Structure 6, because said O-ring is provided in said cap base of said maintenance unit for making said cap base come into close contact with said recording head, and because the material used for said O-ring is perfluoro-elastomer, not only the replacement becomes easy but also durability over long periods can be obtained without any melting, bloating up or slipping due to the chemical constituents contained in the ink, and hence there is the effect that it is possible to retain the maintenance performance capacity of the maintenance apparatus over a long period and that it is possible to carry out maintenance definitely.
According to the invention described in Structure 7, in said ink jet recording apparatus, since it is possible to use inks having a viscosity of 10 to 50 mPa·s and a surface tension of 20 to 40 nM/m at 25° C., there is the effect that in the ink jet recording apparatus it is possible to form images on the recording surfaces of a wide range of recording media types.
According to the invention described in structure 8, since in said ink jet recording apparatus it is possible to use inks of the ultraviolet ray hardening type, there is the effect that in the ink jet recording apparatus it is possible to form very good images on the recording surfaces of a wide range of recording media types.
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An ink jet recording apparatus, including: (1) a recording head to eject ink which is hardened by irradiation of ultraviolet rays; (2) an ultraviolet ray irradiation section to harden the ink ejected from the recording head; and (3) a recording head maintenance device, including, (3-1) a maintenance section for carrying out maintenance of the recording head; (3-2) a coupling section to make the recording head maintenance device to come into close contact with the recording head; and (3-3) a cover section to cover the maintenance section, on which an opening section is formed to make the coupling section to project beyond the maintenance unit cover, including a light shield section to shield the coupling section from the ultraviolet rays emerging from the ultraviolet ray irradiation section.
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BACKGROUND OF THE INVENTION
The invention relates to improvements in apparatus for surface treatment (such as deburring, cleaning or polishing) of metallic, plastic and/or other workpieces. More particularly, the invention relates to improvements in apparatus of the type disclosed in commonly owned U.S. Pat. Nos. 4,218,854, 4,368,599, 4,757,647 and 4,844,232. The disclosures of these patents are incorporated herein by reference. Apparatus of the type to which the present invention pertains are also disclosed in published European patent applications Nos. 205 738 and 289 845.
Commonly owned U.S. Pat. No. 4,844,232 discloses an apparatus wherein the shell of the cage-like receptacle for workpieces is composed of longitudinally extending cable-like, rope-like, wire-like or rod-like components. The end portions of the components are secured to two end walls which act not unlike wobble plates or swash plates and cause the components to move back and forth in parallelism with the axis of rotation of the receptacle to thus advance the workpieces in the interior of the shell in a direction from the one toward the other axial end of the receptacle. As shown in FIG. 4 of this patent, the connections between the end portions of the components and the end walls include ball joints. Each ball joint includes a socket having a concave surface and a spherical head which extends into the socket and is biased against the concave surface. A drawback of such joints is that they are expensive as well as that their parts are subjected to extensive wear when the apparatus is in use. Moreover, such joints are overly affected by certain treating agents for the workpieces in the shell of the receptacle, for example, by certain types of fluids or by certain flowable pulverulent and/or granular solid materials which are propelled against the workpieces to remove burrs, to achieve a certain surface finish and/or for other purposes. Solid particles which penetrate between the socket and the head of a ball joint are likely to rapidly damage or totally destroy the joint. Once a joint fails to function, the respective component is subjected to pronounced bending or flexing stresses whenever the apparatus is put to use, and such repeated flexing causes the material of the component to tire so that the component breaks shortly after partial or complete destruction of the respective ball joint
OBJECTS OF THE INVENTION
An object of the invention is to provide a novel and improved apparatus which is more rugged and the parts of which can stand more pronounced wear than in heretofore known apparatus.
Another object of the invention is to provide a novel and improved receptacle for use in the above outlined apparatus.
A further object of the invention is to provide a receptacle wherein the cable-like, rope-like, rod-like, wire-like or analogous components of the shell are connected to the respective end walls in a novel and improved way.
An additional object of the invention is to provide novel and improved joints between the components of the shell and one or both end walls.
Still another object of the invention is to provide joints which are less likely to be affected by work treating agents than heretofore known joints and the useful life of which is much longer than that of ball joints.
A further object of the invention is to provide an apparatus which can be designed for the treatment of relatively small or larger workpieces or of random mixtures of smaller and larger workpieces.
Another object of the invention is to provide an apparatus wherein a relatively small number of specially designed joints suffices to prolong the useful life of the receptacle for workpieces.
An additional object of the invention is to provide a novel and improved shell for use in the receptacle of the above outlined apparatus.
A further object of the invention is to provide a novel and improved method of prolonging the useful life of the receptacle for workpieces which are to be bombarded by particles of solid material, subjected to the action of flames and/or subjected to the action of gaseous and/or liquid fluids during transport through the shell of the receptacle.
Another object of the invention is to provide the apparatus with novel and improved means for limiting the extent of flexing of end portions of rod-like or wire-like components forming part of or constituting the shell of the receptacle for workpieces.
SUMMARY OF THE INVENTION
The invention is embodied in an apparatus for advancing and changing the orientation of metallic and/or other workpieces, for example, for removing burrs, webs and other undesirable protuberances from metallic or plastic workpieces. The improved apparatus comprises a rotary receptacle having a preferably horizontal or nearly horizontal axis of rotation and including a tubular shell surrounding the axis and having an internal space for workpieces and a plurality of elongated wire-like, rod-shaped or otherwise configurated and/or produced components extending in substantial parallelism with the axis and having first and second end portions. The receptacle further comprises first and second end walls and means for connecting the end walls to the respective end portions of the elongated components. In accordance with a feature of the invention, the connecting means includes universal joints at least between the first end wall and the first end portions of the components, preferably between each of the first and second end walls and the respective end portions of the components. The universal joints are designed to avoid the need for flexing of the end portions of components while the components move longitudinally during rotation of the shell about the axis, at least in a predetermined portion of the shell (preferably in the lower portion beneath the axis of the receptacle). To this end (i.e., in order to ensure that the components will reciprocate during rotation of the shell, the means for rotating the shell about the axis includes means for maintaining the end walls at an oblique angle to the axis of the receptacle s that the end walls act not unlike wobble plates or swash plates which are disposed in two parallel planes.
The joints include resilient means for subjecting the components to longitudinal tensional stresses, and the end walls preferably include rings which are indirectly connected with the respective end portions of the components.
The first end wall is provided with holes for the components, and the first end portions of the components extend with radial play through and outwardly (i.e., away from the second end wall) beyond the first end wall. The joints further include stops which are provided on the first end portions of the components and the resilient means includes or can include springs which react against the first end wall and bear against the respective stops to thereby subject the corresponding components to longitudinal tensional stresses. The springs can include axially stressed coil springs which surround the first end portions of the components between the first end wall and the respective stops.
The first end portions of the components can be provided with external threads, and the stops can include nuts or sets of nuts having internal threads in mesh with the respective first end portions. This renders it possible to select the bias of the springs by the simple expedient of rotating the nuts or sets of nuts relative to the respective components.
Ring-shaped bearings can be interposed between the springs and the respective stops. In addition to or in lieu of such bearings, the apparatus can further comprise a deformable insert which is interposed between the springs and the stops. The arrangement may be such that the first end wall includes a first ring which is provided with the aforementioned holes for the first end portions of the components, and the insert includes a second ring which is or can be concentric with the first ring. The second ring is preferably provided with holes for the first end portions of the components and is elastically deformable, at least in the regions of its holes.
The shell can further comprise additional elongated wire-like or rod-shaped components having first and second end portions which extend through holes, slots or otherwise configurated apertures provided therefor in the first and second end walls. The first end portions of the additional components can be connected with the aforementioned insert and the second end portions of the additional components can be connected to a second ring-shaped insert which is outwardly adjacent the second end wall or forms part of the second end wall. The additional components can be disposed at a first distance and the longitudinally tensioned components can be disposed at a greater second distance from the axis of the receptacle.
Still further, the apparatus can comprise at least one annular supporting member between the first and second end walls. The supporting member is provided with holes and the components of the shell extend through such holes with at least some radial play. Means is provided to hold at least some of the components (e.g., the longitudinally tensioned components) and the at least one supporting member against movement relative to each other in the axial direction of the receptacle. The holding means can comprise pairs of clamping elements (e.g., in the form of nuts) which engage the at least some components and flank the at least one supporting member.
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 presently preferred specific embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a central longitudinal vertical sectional view of an apparatus which embodies one form of the invention, the section being taken in the direction of arrows as seen from the line I--I of FIG. 2;
FIG. 2 is a plan view of the apparatus, with certain parts broken away;
FIG. 3 is an enlarged view of the detail III in FIG. 1; and
FIG. 4 is a plan view of the structure of FIG. 3 as seen in the direction of arrow IV.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIGS. 1 and 2 show certain details of an apparatus wherein workpieces (one shown at 55 in FIG. 1) are subjected to surface treatment during advancement through the elongated tubular shell of a cage-like receptacle 9 which is rotatable about a horizontal or substantially horizontal axis A. The shell surrounds the axis A and includes elongated rod-like, wire-like, cable-like, cord-like or analogous components 27 including larger-diameter outer components 27' (FIGS. 3 and 4) which are more distant from the axis A and smaller-diameter inner components 27" which are nearer to the axis A.
The receptacle 9 extends through the chamber 1 of a housing 3 in such a way that its end walls 11 and 13 are located externally of the housing. The end walls 11, 13 are respectively mounted in carriers 15 and 17 which are secured (by brackets 19) to the housing 3 in a manner to ensure that each of the carriers is turnable with reference to the housing about a discrete vertical axis B, i.e., about an axis which is normal to and preferably crosses the axis A. The apparatus further comprises adjusting means for changing the inclination of the carriers 15, 17 with reference to the axis A, i.e., for turning the carriers about the respective vertical axes B. The adjusting means includes mating face gears 21 on one of the carriers 19 and on the carrier 15. The common axis of the gears 21 coincides with the respective axis B and the gear on the bracket 19 can be rotated by a handle 121. The orientation of the carrier 17 with reference to the corresponding axis B is changed in automatic response to a change of orientation of the carrier 15 because these carriers respectively support the end walls 11, 13 which are connected to each other by the components 27', 27" of the tubular shell forming part of the receptacle 9. FIG. 2 shows that, in the illustrated embodiment, the planes of the end walls 11, 13 make with the axis A an acute angle alpha. The selected magnitude of the angle alpha will determine the extent of reciprocation of the components 27', 27" in response to rotation of the receptacle 9 about the axis A, i.e., the rate of advancement of one or more workpieces 55 in the shell of the receptacle 9. It is equally within the purview of the invention to omit the adjusting means 21, 121 and to install the carriers 15, 17 in such a way that the planes of the end walls 11, 13 are maintained at a fixed angle alpha with reference to the axis A.
Each of the carriers 15, 17 supports at least three preferably equidistant first rollers 23 and at least three preferably equidistant second rollers 25. These rollers together constitute bearings for the respective end walls 11 and 13, i.e., each of these end walls can rotate relative to three or more rollers 23 and relative to three or more rollers 25. The axes of the rollers 23 on each of the carriers 15, 17 intersect each other on the axis A, and the axes of rollers 25 on each of the carriers 15, 17 extend at right angles to the respective axes B.
Each end wall comprises a ring 79, and the ring 79 of the end wall 13 is surrounded by and connected to or integral with a sprocket wheel or toothed pulley 41. A second sprocket wheel or toothed pulley 47 is mounted on the output shaft of a reversible variable-speed electric motor 45 or another suitable prime mover, and the means for transmitting torque from the motor 45 to the end wall 13 comprises an endless chain or toothed belt 43 which is trained over the parts 41 and 47. The end wall 13 rotates the end wall 11 through the medium of the components 27' and 27".
The rings 79 of the end walls 11, 13 are provided with relatively large centrally located openings 51 which are bounded by cylindrical or conical surfaces. The mutual spacing of components 27' and 27" in the circumferential direction of the rings 79 depends upon the dimensions and/or weight of workpieces which are to be treated on their way from the opening 51 of the ring 79 forming part of the end wall 13 toward the opening 51 of the other ring 51 or in the opposite direction, depending upon the direction of rotation of the receptacle 9. The rollers 23 engage the sides and the rollers 25 engage the peripheral surfaces of the respective rings 79. Each ring 79 is concentric with an at least partially elastic second ring 81 which can be called an insert and the purpose of which will be described with reference to FIGS. 3 and 4.
The apparatus further comprises one or more annular supporting members 89 which are disposed between the end walls 11, 13 in the chamber 1 of the housing 3 and have holes or bores 91 (FIG. 3) for the respective components 27', 27". The arrangement is such that the components 27' and 27" extend through the respective holes or bores 91 (hereinafter called holes) with a certain amount of radial play. FIG. 2 shows that the illustrated apparatus comprises a total of four substantially equidistant supporting members 89. The inclination of these supporting members can equal or approximate the inclination of the end walls 11 and 13. Pairs of combined clamping and distancing elements 93 (FIGS. 3 and 4) are provided to hold the supporting members 89 and the components 27', 27" against movement relative to each other in the longitudinal direction of the components. The illustrated clamping members 93 are nuts having internal threads in mesh with external threads on the adjacent portions of the respective components 27' and 27". The supporting members 89 ensure that the mutual spacing of neighboring components 27', 27" in the circumferential direction of the shell of the receptacle 9 remains substantially unchanged which is particularly desirable when the workpieces are small or thin so that they could escape into the chamber 1 around the shell of the receptacle 9 in response to a pronounced widening of the slots between neighboring components 27' and 27". The mutual spacing of neighboring inner components 27" is smaller than that of the outer components, i.e., the workpiece or workpieces 55 are actually engaged, advanced and confined by the tubular array of inner components 27". The outer components 27' are subjected to rather pronounced longitudinal tensional stresses by novel and improved universal joints one of which is shown in full detail in FIGS. 3 and 4. The outer components 27' and the end walls 11, 13 can be said to constitute a skeleton frame of the receptacle 9, and the inner components 27" can be said to constitute that portion of the tubular shell of the receptacle which confines, guides and advances the workpieces on their way from the end wall 11 toward the end wall 13 or in the opposite direction.
The end portions of the outer components 27' extend, with considerable radial play, through bores or holes 95 of the rings 79 and, with lesser radial play, through the bores or holes 97 of the ring-shaped inserts 81. The outer ends of end portions of the components 27' are provided with external threads 99 (FIGS. 3 and 4). The clearances between the end portions of the components 27' and the surfaces bounding the holes 95 and 97 should suffice to ensure that the components 27' are not flexed in response to rotation of the receptacle 9 about its axis A, i.e., the components 27' should not jam in the rings 79 and/or inserts 81 and need not even touch the parts 79, 81 when the receptacle is rotated by the motor 45.
The inserts 81 are disposed outwardly of the respective rings 79, and the space between each insert and the respective ring 79 accommodates pairs of ring-shaped bearings 101, 103 and coil springs 105. The bearings 101 abut the outer sides of the respective rings 79 and extend in part into the respective holes 95, and the bearings 103 abut the inner sides of the respective inserts 81. Each spring 105 reacts against the respective bearing 101 and bears against the respective bearing 103 to thereby subject the corresponding component 27' to a longitudinal tensional stress because the insert 81 bears against one of two stops 107 in the form of nuts having internal threads in mesh with the external threads 99 of the respective components 27'. The inserts 81 are optional, i.e., the bearings 103 can directly abut the adjacent nuts 107 to ensure adequate axial stressing of the components 27'. The bias of the springs 105 can be changed by rotating the nuts 107 on the respective components 27'. Alternatively, the apparatus can be furnished with two or more sets of springs having different characteristics.
Since the illustrated apparatus employs two ring-shaped inserts 81, these inserts must be configurated, mounted and made in such a way that they do not cause any, or any pronounced, flexing of the respective end portions of components 27' when the receptacle 9 is caused to rotate about the axis A and the components 27' move back and forth, at least in the lower portion of the shell, namely beneath the axis A. For example, the inserts 81 can be made of polyurethane and should be capable of undergoing elastic deformation, at least in the regions of their holes or bores 97 (see FIG. 4, as at 181) so that those portions of the inserts which are immediately adjacent and surround the components 27' are disposed in planes extending at right angles to the longitudinal axes of the components 27'. Thus, while it is not necessary to make the inserts 81 exclusively of an elastomeric material, those portions of the inserts which are clamped between the bearings 103 and the respective nuts 107 should be capable of pronounced elastic deformation in order to remain in planes which are normal to the axes of the components 27'. The readily deformable portions 181 of the inserts 81 are incapable of subjecting the components 27' to appreciable bending or flexing stresses. This prolongs the useful life of the components 27' and reduces the frequency and shortens the down times of the apparatus.
The feature that the end portions of the components 27' are not subjected to any pronounced bending or flexing stresses in spite of the absence of ball joints reduces the likelihood of premature tiring of the material and subsequent breakage of the components 27' when the apparatus is in use, i.e., when the receptacle 9 rotates about the axis A and the components 27' are compelled to move back and forth because the rings 79 of the end walls 11, 13 cooperate with the respective carriers 15, 17 to act not unlike wobble plates or swash plates and to compel the components 27' to reciprocate when the receptacle is set in rotary motion.
It will be noted that the springs 105 and the associated nuts or stops 107 constitute relatively simple but highly effective universal joints which replace the heretofore used ball joints and enable the components 27' to reciprocate without any, or without any appreciable, flexing when the receptacle 9 is set in rotary motion. All that is necessary is to ensure that the end portions of the components 27' extend through the respective bores or holes 95 of the rings 79 with requisite radial play so that the rigid rings 79 cannot cause pronounced flexing of the components 27' when the apparatus is in use.
The inner components 27" extend, with radial play, through the bores or holes 92 of the inserts 81 and the registering holes 91 of the supporting members 89. The rings 79 can be provided with rather large apertures for the end portions of the components 27". The inserts 81 are flanked by pairs of clamping elements 93 (e.g., internally threaded nuts mating with external threads of the components 27") to hold the end portions of the components 27' against axial movement relative to the inserts 81. The clearances between the components 27" and the surfaces bounding the holes 91, 92 should suffice to prevent jamming of components 27" in the supporting members 89 and/or in the inserts 81. The holes 91 of the supporting members 89 are equidistant from each other in the circumferential direction of the shell of the receptacle 9, the same as the holes or bores 92 in the inserts 81. Those surfaces of the clamping elements 93 which confront the supporting members 89 and the inserts 81 are preferably conical or crowned so that they are in mere linear contact with the adjacent surfaces of the parts 89 and 81. The conicity of such surfaces of the elements 93 preferably matches or even exceeds the selected angle alpha. This ensures that the conical or crowned surfaces of the elements 93 can roll along the adjacent surfaces of the supporting members 89 and inserts 81.
FIG. 1 shows schematically a spraying unit 57 with three nozzles 59 which can propel solid particles, streams of a gaseous fluid and/or streams of a liquid medium against one or more workpieces 55 within the confines of the tubular body formed by the inner components 27". The material which is discharged by the nozzles 59 is caused to flow upwardly and to penetrate through the lower portion of the shell on its way into contact with the workpiece or workpieces 55.
The operation is as follows:
One or more workpieces 55 and/or otherwise configurated and/or dimensioned workpieces are introduced into the receptacle 9 by way of the opening 51 in the ring 79 of the end wall 11 or 13, either by hand or by resorting to suitable conveyor or transfer means. The workpieces come to rest on the components 27" in the lower portion of the shell of the receptacle 9. The operator then selects the inclination (angle alpha) of the planes of the end walls 11, 13 with reference to the axis A, and the motor 45 is started to rotate the receptacle 9 in a clockwise or in a counterclockwise direction. The selected inclination of the planes of the rings 79 determines the extent of reciprocation of the components 27', 27" and hence the speed at which the workpiece or workpieces 55 are advanced in the receptacle 9. The direction of rotation of the receptacle 9 and the orientation of the end walls 11, 13 determine the direction of advancement of the workpiece or workpieces. Each workpiece is caused to tumble and/or perform other movements on its way from one of the end walls 11, 13 toward the other end wall so that each of its sides or surfaces (including the surfaces in cavities, recesses, holes, bores or like configurations) is adequately treated before the workpiece leaves the shell. The treatment can involve bombardment with particles of dust or granulae simultaneously with or without treatment with a gaseous and/or liquid fluid. The agitation of each workpiece is sufficiently pronounced to ensure that the holes, bores, cavities and/or recesses (if any) of the workpieces are not likely to accumulate solid particulate material which is propelled by the nozzles 59 of the spraying unit 57. The distance of those surfaces of workpieces which undergo treatment from the orifices of the nozzles 59 remains substantially constant because the propelled material impinges primarily upon the downwardly facing sides of workpieces in the lower portion of the shell forming part of the receptacle 9. This holds true irrespective of the size and shape of the workpieces in the tunnel between the end walls 11 and 13. By selecting the RPM of the motor 45 (i.e., the rotational speed of the receptacle 9) and/or the angle alpha of the planes of the end walls 11, 13 relative to the axis A, an operator or an automatic control unit can select the period of dwell of a workpiece in the receptacle 9 as well as the duration of treatment of each workpiece by the material issuing from a particular nozzle 59.
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.
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Apparatus for surface treatment of workpieces has a rotary horizontal cage with inclined end walls and a set of elongated rod-shaped or bar-shaped components between the end walls. The end walls are rotatable in inclined carriers which cause them to act not unlike swash plates and to cause the components to reciprocate in response to rotation of the cage about its axis. The end portions of the components are tensioned by springs which react against the end walls and bear against axially adjustable nuts at the free ends of the components at the outer sides of the end walls. The end walls have relatively large holes to ensure that the components are not flexed during reciprocation in response to rotation of the cage. Workpieces to be treated, e.g., by sprays of solid particles, are introduced through one of the end walls and advance toward the other end wall at a speed which is determined by the extent of reciprocatory movement of the components and the rotational speed of the cage.
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BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a data reader which compares an analog signal from a reading means for reading recorded data with a reference voltage signal so as to convert the analog signal into a digital signal.
An optical data reader such as a bar code reader is conventionally known. In such a reader, light is radiated onto a medium on which predetermined data is recorded (printed) in the form of bar codes. The differences in reflectivity are converted into an electrical signal (magnitude of a current) for allowing reading of the bar code data. A data reader for magnetically reading such data is also known.
Methods of converting an analog signal into a digital signal of logic level "0" or "1" include the DC method and the AC method. FIG. 1 shows a conventional bar code reader which adopts the DC method. The bar code reader has a hand scanner 2 for manually scanning a medium (label) 1 on which bar codes are recorded, an amplifier 3 for amplifying the analog signal read by the hand scanner 2, a comparator 4 which receives at its positive input terminal an analog signal from the amplifier 3, and a variable resistor 5 for supplying a reference input voltage to the negative input terminal of the comparator 4. The comparator 4 produces a digital signal which corresponds to the output voltage from the amplifier 3.
A conventional bar code reader adopting the AC method has, for example, the structure as shown in FIG. 2. The same reference numerals as used in FIG. 1 denote the same parts as in FIG. 1, and a detailed description thereof will be omitted. The bar code reader further has a differentiator 6 consisting of a capacitor C1 and a resistor R. The differentiator 6 receives an output voltage from the amplifier 3 and cuts off the DC component of the input voltage so as to obtain an AC component thereof. The reader also has a buffer amplifier 7 for non-inverting amplification of an output from the differentiator 6. An output from the buffer amplifier 7 is supplied to the positive input terminal of the comparator 4. In this case, the negative input terminal of the comparator 4 receives a ground level voltage as a reference voltage.
In each of the bar code readers adopting the AC and DC methods, the reflectivity differs depending upon the quality of the label 1 or the quality of the ink used for printing the black bars. Then, the waveform of an output signal from the amplifier 3 has a different amplitude and includes a DC component. If the densely arranged bars are thin, a DC component is further included in the output signal from the amplifier 3 which has a waveform as shown in FIG. 3 waveform (A).
In view of this problem, the reference voltage to be supplied to the comparator 4 must be adjusted by the variable resistor 5 in a bar code reader adopting the DC method. However, such adjustment is extremely difficult to perform. On the other hand, in the reader adopting the AC method, an output from the buffer amplifier 7 has an attenuated oscillating waveform which is obtained by non-inverting amplification of an AC component after cutting off a DC component, by means of the differentiator 6, as shown in FIG. 3 waveform (B). When an output from the buffer amplifier 7 is compared with ground level (GND) by the comparator 4, the input signal does not fall below the threshold level at its initial portion, as shown in FIG. 3 waveform (C), so that correct A/D conversion cannot be performed. As a result, a bar code reader of this type cannot read densely recorded bars and can only read loosely recorded bar codes.
Since the attenuated oscillating waveform is compared with a predetermined threshold level, the pulse width of the resultant digital signal is significantly disturbed.
SUMMARY OF THE INVENTION
Accordingly the object of the present invention is to provide a data reader which is capable of converting any analog signal from a data reading means for reading recorded data into a correct digital signal.
In order to achieve the above object, there is provided according to the present invention a data reader comprising: data reading means for reading recorded data from an external recording medium and for producing an analog signal; a switching circuit having one terminal connected to an output terminal of said data reading means, said switching means being turned off when a potential difference between said one terminal thereof and the other terminal thereof falls within a predetermined range and said switching means being turned on when the potential difference falls outside the predetermined range; a hold circuit connected to the other terminal of said switching circuit and holding a potential applied thereto; and a comparator having a first input terminal connected to a node between said data reading means and said one terminal of said switching circuit and a second input terminal connected to a node between the other terminal of said switching circuit and said hold circuit, said comparator comparing a potential of the analog signal supplied to said first input terminal with a potential held by said hold circuit and supplied to the second input terminal, thereby producing a digital signal.
The reader of the present invention having the configuration as described above need not perform adjustment or the like of a reference voltage to be supplied to the comparator. Furthermore, the drawbacks of the conventional reader are eliminated; neither the problem of incorrect A/D conversion at the initial portion of the input signal nor the problem of significant disturbance in the pulse width occurs. Irrespective of density or the like of the recorded data, an analog signal can be correctly converted into a digital signal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view showing a conventional bar code reader adopting the DC method;
FIG. 2 is a view showing a conventional bar code reader adopting the AC method;
FIG. 3 shows the waveforms of signals at the respective parts of the readers shown in FIGS. 1 and 2;
FIG. 4 is a circuit diagram of a data reader according to an embodiment of the present invention;
FIG. 5 shows the waveforms of signals at the respective parts of the reader shown in FIG. 4; and
FIG. 6 is a perspective view of a data reader according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first preferred embodiment of the present invention will now be described with reference to FIGS. 4 and 5. A data reader of this embodiment is an optical bar code reader which adopts the AC method as described above. The same reference numerals as used in FIG. 2 denote the same parts in FIG. 4, and a detailed description thereof will be omitted. This embodiment includes a variable reference voltage generator 8 which is connected between the buffer amplifier 7 and the comparator 4. The variable reference voltage generator 8 varies the reference voltage to be supplied to the negative input terminal of the comparator 4 in accordance with an analog signal from the buffer amplifier 7.
The variable reference voltage generator 8 has a switching element 9 which, in turn, consists of a series circuit of Zener diodes D1 and D2 with their cathodes opposing each other. The anode of the Zener diode D1 is connected to a node X between the output terminal of the buffer amplifier 7 and the positive input terminal of the comparator 4. A capacitor C is interposed between the anode of the Zener diode D2 and ground. The capacitor C is parallel-connected to a diode D3 and a Zener diode D4 having their anodes opposing each other. The cathode of the diode D3 is connected to a node Y between the capacitor C and the Zener diode D2, and the cathode of the Zener diode D4 is connected to ground. Potential VY at the node Y between the Zener diode D2 and the capacitor C is supplied as a reference voltage to the negative input terminal of the comparator 4.
The mode of operation of the data reader having the configuration as described above will now be described with reference to FIGS. 4 and 5. Referring to FIG. 5 part (A), a solid curve shows the waveform of potential VX at the output point X of the buffer amplifier 7, while a broken curve shows the waveform of the potential VY at the output point Y of the variable reference voltage generator 8.
The switching element 9 is turned on when the difference between the potentials VX and VY at the points X and Y, respectively, exceeds a predetermined value. Then, a current flows from the point at the higher potential to the point at the lower potential. The switching element 9 is turned off when the potential difference is below the predetermined value. The condition for a current to flow from the point X to the point Y when the potential VX is higher than the potential VY is that the potential difference between the potentials VX and VY satisfies relations (1) and (2) below:
VX-VY≧V1 (1)
V1=VF1+VZ2 (2)
where VF1 is the forward voltage of the Zener diode D1 and VZ2 is the Zener voltage of the Zener diode D2.
The condition for a current to flow from the point Y to the point X when the potential VY is higher than the potential VX is that the potential difference between the potentials VX and VY satisfies the following relations (3) and (4):
VY-VX≧V2 (3)
V2=VF2+VZ1 (4)
where VF2 is the forward voltage of the Zener diode D2 and VZ1 is the Zener voltage of the Zener diode D1.
When the potential VX is lower than the ground level (GND) by a voltage VA satisfying relation (5) below as shown in FIG. 5, the potential VY is equal to the potential at the cathode of the diode D3 and is lower than the ground level (GND) by a voltage VB satisfying relation (6) below.
VA≧V2+VF3+VZ4 (5)
VB=VF3+VZ4 (6)
where VF3 is the forward voltage of the diode D3 and VZ4 is the Zener voltage of the Zener diode D4.
When the potential VX at the point X increases and reaches a value to satisfy equation (7) below, the switching element 9 is turned on in the direction from the point X to the point Y and a current flows from the point X to the point Y.
VX≧V1+(-VB) (7)
Thus, the potential VY increases with an increase in the potential VX.
When the potential VX reaches an upper peak voltage VXP and thereafter the potential VX decreases to finally satisfy relation (8) below, the switching element 9 is turned off.
VX-VY<V1 (8)
Consequently, the potential VY is held at a potential VYP lower than the peak potential at the point X by the potential difference V1, by means of the potential holding effect (holding effect) of the capacitor C. When the potential VX is further decreased to satisfy relation (9) below, the switching element 9 is turned on in the direction from the point Y to the point X and a current flows from the point Y to the point X. Thus, the potential VY is decreased with a decrease in the potential VX.
VX<VYP-V2 (9)
When the potential VX reaches a lower peak voltage VXP' and then increases to satisfy relation (10) below, the switching element 9 is turned on again. As a result, o the potential VY is held at a potential VYP' higher than the peak voltage VXP' at the point X by the potential difference V2.
VY-VX<V2 (10)
When the potential VX further increases to satisfy relation (11) below, a current flows from the point X to the point Y again, and the potential VY increases with an increase in the potential VX.
VX>V1+VYP' (11)
A similar operation to that described above is repeated. Then, the potential VY has a waveform indicated by the broken line which is like a waveform obtained by omitting the portions near to peaks of the waveform of the potential VX indicated by the solid line in FIG. 5 part (a).
Since the AC voltage having such a waveform is applied to the negative input terminal of the comparator 4, the comparator 4 compares the two input signals and produces a signal of logic level as shown in FIG. 5 part (B).
With the reader of the present invention, no error is generated in conversion of an initial portion of an analog signal into a digital signal. Furthermore, the resultant digital signal does not have a notably irregular pulse width. The variable reference voltage generator 8 may also be applied to a bar code reader adopting the DC method as shown in FIG. 1. In this case, the reader has the following configuration. The variable resistor 5 is omitted. The anode of the Zener diode D1 is connected to a node between the output terminal of the amplifier 3 and the positive input terminal of the comparator 4. The node between the anode of the Zener diode D2 and the capacitor C is connected to the negative input terminal of the comparator 4.
FIG. 6 is a schematic perspective view showing a data reading means according to another embodiment of the present invention. This embodiment is applied to a magnetic data reader for reading data recorded magnetically.
A card 10 is inserted into a groove 14 formed in a card reader 12. Data recorded on a magnetic recording portion 11 of the card 10 is read out by a magnetic head 13 and is produced as an analog signal.
If the variable reference voltage generator 8 as shown in FIG. 4 is used as a circuit for converting this analog signal into a digital signal, an analog signal from the magnetic head 13 can be reliably converted into a digital signal.
In the embodiments described above, the switching element comprises two series-connected Zener diodes. However, the present invention is not limited to this. For example, a first group of a plurality of diodes may be series-connected in the forward direction, and then a second group of a plurality of series-connected diodes may be parallel-connected in the opposite direction to the first group of diodes.
The Zener diodes D1, D2, and D4 respectively need not be single Zener diodes but may be a combination of a plurality of Zener diodes. Similarly, each of the capacitors C and C1, the diode D3, the resistor R and so on need not comprise a single element, but may be a combination of a plurality of elements.
The each embodiment described above, is a data reader for optically reading bar code data by the AC or DC method and to a data reader for magnetically reading data recorded on a card. However, the present invention is not limited to this. The present invention may be similarly applied to various other types of data readers such as a data reader for optically or magnetically reading characters.
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A data reader has a data reading means for reading data from a recording medium and producing an analog signal. The data reader also has a switching circuit having one terminal connected to the output terminal of the reading means. When the potential difference across the two terminals of the switching circuit falls within a predetermined range, the switching element is turned off. The switching element is turned on when the potential difference falls outside the predetermined range. The reader further has a hold circuit connected to the switching circuit and for holding a potential applied thereto. The reader also has a comparator which compares the analog signal from the data reading means with the potential held by the hold circuit and which produces a digital signal.
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[0001] The present invention relates to a sediment capping method and system. In one aspect the present invention relates to an improved broadcast sediment capping method. In another aspect, the invention relates to an improved sub-aquatic contaminated sediment capping system.
BACKGROUND OF THE INVENTION
[0002] Sub-aquatic contaminated sediments often represent a harmful and long term source of pollutants to the environment. A variety of approaches, such as dredging, have been used for the treatment of contaminated sediments, but they are expensive and can have limited value. Due to the increased volume of contaminated sediment cleanup projects both in the U.S. and abroad, sediment capping has become an option. In many areas the removal of material from a water body is not cost effective. In-situ capping of contaminated sediment is an efficient alternative that can have an immediate beneficial impact on the environment, as the contaminated sediment is isolated from aquatic organisms. Furthermore, capping contaminated sediments generally creates an anaerobic environment which permits natural degradation processes, which provide an opportunity for destruction and detoxification of harmful contaminants. Sediment capping has been used to contain harmful contaminants, including pesticides, metals, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and polynuclear aromatic hydrocarbons (PAHs).
[0003] The capping of contaminated sediments is designed to prevent the upward migration of residual contaminants and/or to provide a clean subsurface bed of sediment that can be colonized by uncontaminated organisms. Capping alone could be used as a strategy to eliminate the need for dredging or could be used in conjunction with dredging to cover dredged locations with a clean layer of material where target clean-up goals cannot be achieved.
[0004] Previous methods of capping contaminated sediments have often involved mechanical equipment using buckets or direct slurry discharge into a water body. The mechanical bucket method often requires dumping large volumes of capping material into the water using a variety of buckets, including a clamshell bucket or dragline bucket. After releasing a bucket load it falls through a water column often as a distinct mass, which usually comes to rest on top of the contaminated material. This method has had some success in deep water producing caps with designed thickness over 12″. The water depth allows the capping material to disperse somewhat reducing velocity and concentration as it travels downward through the water. The thick cap design then accommodates the placement inaccuracies inherent in mechanical bucket placement.
[0005] The mechanical bucket method poses problems for relatively shallow water depth capping. When the mechanical bucket method is used to install thin layer caps (3″ to 12″), especially in shallow water (less than 10′), the results are often problematic. The capping material travels a relatively short distance through the water, thus causing its weight and velocity to displace the soft contaminated sediments. Displacement of the contaminated sediment is adverse to the purpose and goals of sediment capping. Furthermore, bucket placement of capping material leaves uneven mounds, which must then be raked in order to produce the proper thickness. This raking action often disturbs the underlying sediments, thereby causing sediment mixing and re-suspending of both the capping material and the contaminated sediments. The raking step can result in low production rates and capping material waste, and therefore higher production costs. In addition, bucket placement requires deep vessel draft requirements and cannot be employed in relatively shallow operations.
[0006] An alternative known capping method involves the open water slurry discharge method. Due to the large volume of water needed to transport the sand or gravel material this method also tends to displace the soft underlying material needing to be capped. Another problem with this method is that it requires sand or gravel slurry to be directly placed in water which raises turbidity levels. It would be advantageous for a sediment capping process to provide delivery of granular material from shallow draft vessels at relatively high rates of production with minimal disturbance of the sub-aquatic sediment.
SUMMARY OF THE INVENTION
[0007] In one embodiment, the invention is a sediment capping system having a spreader barge comprising a capping material spreading means and a spreader pool where the spreading means is configured to distribute capping material into the spreader pool. The system also includes a template barge for guiding the spreader barge while the capping material is distributed to a sub-aquatic sediment. The spreader barge and the template barge include a positioning means. The system further includes a capping material providing means, wherein the capping material is received by the intake means and distributed by the spreading means.
[0008] In another embodiment, the invention is a sediment capping system comprising a spreader barge for distributing a capping material over contaminated sub-aquatic sediment, a template barge configured to guide the movement of the spreader barge during distribution of the capping material, and a sub-aquatic elevation measuring means. The capping material distribution has limited disturbance of the sediment and the measuring means can acquire real-time elevation data.
[0009] In yet another alternative embodiment, the invention is a method for capping sub-aquatic sediment including identification of a sub-aquatic region for distributing a layer of capping material and providing a source of capping material to a capping system. The capping system includes a template barge, a spreader barge, and a broadcast spreader means. The template barge guides the spreader barge along a pre-determined path while capping material is distributed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a top plan view of a broadcast spreader in accordance with at least one embodiment of the present invention.
[0011] FIG. 2 is a side view of the broadcast spreader according to FIG. 1 .
[0012] FIG. 3 is a hopper for distributing and metering particulate matter in accordance with at least one embodiment of the present invention.
[0013] FIG. 4 is a block diagram representing a process for sub-aquatic capping in accordance with at least one embodiment of the present invention.
[0014] FIG. 5 is a side perspective view of the spreading means in accordance with at least one embodiment of the present invention.
[0015] FIG. 6 is a perspective view of a capping material distribution spinner in accordance with at least one embodiment of the present invention.
[0016] FIG. 7A is a perspective view of the spreading means in accordance with an alternative embodiment of the present invention.
[0017] FIG. 7B is a perspective view of the spreading means of FIG. 7A in use and depicting a spreading pattern, in accordance with an alternative embodiment of the present invention.
[0018] FIG. 8 is a perspective view of a capping material distribution spinner in accordance with an alternative embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Referring to FIGS. 1 and 2 , sediment capping system 10 is provided. System 10 includes spreader barge 12 , template barge 14 , and capping material providing means 16 . Spreader barge 12 includes capping material receiving means 18 , capping material shaker 20 , slurry water output 22 , capping material spreading means 24 , control center 26 , distribution pool 28 , capping material reservoir 29 and at least one positioning means 30 . Template barge 14 is releasably engaged with spreader barge 12 while the capping material is being distributed by spreader barge 12 . Barge 14 includes at least one positioning means 30 , fuel tank 32 , and barge movement means 34 . Spreader barge 12 and template barge 14 float on waterway surface 35 . The slurry enters the spreading barge 12 through the providing means 16 and is received by the receiving means 18 , which can be a hopper or alternative structure designed to receive capping material slurry. The shaker 20 separates the capping material from the water contained within the slurry. The water is evacuated through the slurry water output 22 and the capping material is distributed within the pool 28 by the spreading means 24 . While the barges 12 , 14 are floating on the waterway, the positioning means 30 , when deployed, prevents the barges 12 , 14 from laterally moving across the waterway. In at least one embodiment of the invention, the slurry water output 22 is a discharge pipe integrally connected to a liquid diffuser. As shown in FIGS. 1 and 2 , the positioning means 30 are positioning spuds.
[0020] Representative capping materials include but are not limited to sand, gravel, chipped stone, rocks, pebbles, and other solid particulate or granular matter suitable for sediment capping. By example, granular capping materials can range from about 0.1 mm to about 10 mm in size. Stones and rocks used for capping material can range from about ½ inch to about 2 inches. Capping material is transported through pipeline 16 , typically in the form of a slurry, and is received by spreader barge 12 at shaker 20 . Capping material slurry is the combination of water and solid capping material, which is more easily transported then dry capping material. An exemplary slurry includes a density of about 15% to about 20% by weight capping material. At this exemplary density range a capping material distribution production rate can range from about 60 to about 80 cubic yards per hour. Depending upon the type of capping material, the slurry density can be less than 15% by weight or greater than 20% by weight. Alternatively, the slurry can include granular additives suitable for use in sediment capping. Receiving means 18 can be a hopper or velocity box and is strategically selected based upon the configuration of providing means 16 , and the type of capping material used. In an alternative embodiment, providing means 16 can be a variety of capping material transportation means, such as barge transportation, airlift transportation, and extended conveyor transportation. The barge transported capping material can be fed into spreader barge 12 by bucket. This may be desirable when transport distances are excessive, or navigational concerns prevent delivery by slurry pipeline 16 .
[0021] Capping material shaker 20 processes the slurry by separating the capping material and the water. Water is gravitationally removed through the slurry water output 22 , which is a pipeline evacuated into distribution pool 28 . The output 22 can also include a water pump for quicker evacuation of the water. The slurry water often contains fine particulate matter. In an effort to avoid contamination of the waterway it is dispensed within distribution pool 28 . The distribution pool is a region of the water way confined by the barge 12 . Fine capping material pieces remain with the water while the capping material is removed within the shaker 20 . As the slurry water is evacuated it enters the pool, the remaining particles gradually sink to the sediment. Since the pool 28 is contained by the barge 12 , water currents and surface waves have less effect on the particles, thereby preventing them from dispersing through the water way. Alternatively, the slurry water can be filtered. The capping material is collected within a reservoir 29 and then distributed within the pool 28 by the distribution means 24 . Spreading means 24 can be a broadcast spreader and alternatively can be selected from a variety of spreader mechanisms. (See FIGS. 5 and 6 ). Distribution pool 28 is an open area configured to contain capping material as it is being distributed by the spreading means 24 in order to efficiently and accurately control capping material distribution to sediment layer 37 .
[0022] Movement of the spreader barge with respect to the template barge is performed by barge movement means 34 . Movement means 34 is an engine or winch operated by either a gas or electric fuel source. Engine 34 causes movement of spreader barge 14 with respect to template barge 12 . Additionally, when template barge 14 is re-positioned, movement means 34 causes movement of template barge 14 while spreader barge 12 is stationary. Alternatively, movement means 34 comprises a motor operated vehicle, by example, a wheel or caterpillar driven tractor or truck mounted on the template barge. In yet another alternative embodiment, both template barge 14 and spreader barge 12 include a fuel source 32 and movement means 34 .
[0023] At least one embodiment of the present invention includes distribution of capping material through slurry pipeline 16 . Referring to FIG. 3 , capping material conveyor 36 is provided for metering and distribution of capping material to spreader barge 12 through pipeline 16 . The conveyor 36 includes a metered hopper 38 into which capping material is loaded and a conveying means 39 configured for metered transportation of capping material to a slurry hopper. The capping material flows from the hopper 38 onto the conveying means 39 , which is situated beneath the hopper 38 . Loading the capping material into the conveyor 36 can be manual or through an automated conveyor means (not shown). Conveyor 36 then transfers capping material into a slurry hopper (not shown). The slurry hopper is a reservoir that has a water intake, a water overflow, and a slurry pump connected to slurry line 16 . The water intake receives water from a water source and combines the water and capping material within the slurry hopper to form a slurry. A combination of the water and dumping of capping material into the hopper from the conveyor 36 provides a mixing action which allows slurry formation. The slurry enters the pipeline 16 and is evacuated through pressure generated by the slurry pump. Excess water is removed through a water overflow pipeline, and is filtered prior to placement back into the waterway. A slurry pump provides a means for forcing the capping material slurry through pipeline 16 to spreader barge 12 . The feed rate of the capping material is metered by a feed opening and/or the variable speed of conveyor 36 . For the purpose of maintaining material balance, metering at the hopper loading location is important in order to assess the mass rate of delivery to spreader barge 12 . Long transport distances may require additional booster pumps (not shown) in order to maintain adequate slurry velocities. By example, slurry velocities for gravel slurry can range from about 10 feet per second (to about 12 feet per second. Gravel slurry velocities less than 10 feet per second and greater than 12 feet per second are contemplated. In at least one embodiment, system 10 is employed within a river having an extended region of contaminated sediment. Within this embodiment slurry pipeline 16 extends in excess of ½ mile. As spreader barge 12 moves farther away from land-based conveyor 36 , pipeline 16 is lengthened and booster pumps added to keep the slurry moving to spreader barge 12 .
[0024] System 10 allows capping material to be deposited evenly over underlying sediments, which can be soft, hard or a mixture of varying densities. One common use of the system is for “capping” contaminated sediments, and it is particularly well suited for shallow water placement of thin layer caps in an efficient manner over large areas with minimal disturbance of the contaminated sediment. Various embodiments of the present invention present a low-cost and environmentally friendly option for treating contaminated waterway sediments. Waterways include lakes, streams, rivers, flowages, reservoirs, and alternative open water sources. Embodiments of the present invention can be used in any water body, and particularly relatively shallow waterways where thin layer capping is required.
[0025] System 10 reduces costs relative to previously known capping methods by allowing rapid placement of capping material over large areas. In addition, various embodiments of the present invention allow tighter capping tolerances, which reduce the amount of capping material needed. This capping process allows for broadcast placement of sands and/or gravels for the purpose of in situ capping of contaminated sediments.
[0026] FIG. 4 is a block diagram representing a plurality of steps in the sediment capping process. A contaminated sediment region is identified at step 40 and the region is mapped at step 42 . Mapping step 42 includes identification of various capping variables, including the type of capping material to be employed, the distribution rate of the capping material, the size of distribution pool 28 , spreader barge 12 and template barge 14 movement sequence. After the region has been mapped, template barge 14 is positioned 44 at a distribution sequence starting position. Spreader barge 12 is then positioned 46 along side the template barge. At step 48 , the capping material is provided to spreader barge 12 and the capping material is distributed within pool 28 at step 50 . While the capping material is being distributed, the metering hopper and belt scale measure the weight of capping material distributed in real time. The weight measurements are compared to the predetermined capping material distribution amounts. As part of the verification process the sub-aquatic elevation of the capping material is measured at step 52 . This can be performed through manual coring to verify the cap thickness. A distribution decision is made at step 54 . If the proper amount of capping material was distributed, then the spreader barge changes its position at step 56 . If an inadequate amount of capping material was distributed, then step 50 is repeated. The rate and sequence timing of the capping material distribution can be automatically altered based upon coring data. The size of barges 12 , 14 and the size of pool 28 can determine the number of spreader barge 12 repositioning steps prior to repositioning of template barge 14 . A repositioning sequence includes the initial positioning of template barge 14 and subsequent step-like repositioning of spreader barge 12 . By example, the time for each spreader barge 14 “step” is in a range of about 2 minutes to about 5 minutes. The “step” time is dependant upon the production rate and the cap depth. The capping material is distributed during each spreader barge 12 step. In an alternative example, the spreader barge step is less than about 2 minutes or greater than about 5 minutes. After a set number of spreader barge 12 steps 56 , spreader barge 12 is positioned at step 58 . Template barge 14 is then repositioned at step 60 . Step 62 determines whether the capping process is complete. If more capping is required, then step 50 is repeated; otherwise the process is completed at step 64 .
[0027] Once the capping material is transported across the water body, via transportation barge, pipeline, or alternative means, it then enters spreader barge 14 . Barges 12 and 14 work in unison by walking on spuds 30 in a linear path parallel to one another. Spreader barge 12 , by example, is about 40 feet wide by about 80 feet long. Template barge 14 , by example, is about 20 feet wide and about 120 feet long. Both barges 12 and 14 have spuds 30 , which include hydraulic power-packs and winches. Except during initial placement, and movement to an alternative capping area, at least one of barges 12 and 14 is positioned and securely placed at all times. Alternatively, barges 12 and 14 can both be moved based upon elevation data or severe weather. When spreader barge 12 is moving, template barge 14 will have at least one spud 30 down which will hold barge 12 in place. Spreader barge 12 moves along the template barge 14 at a predetermined even rate until reaching its stopping point. At this time, spreader barge 12 is positioned and the template barge will step back. During these steps, distribution of the material is continuous, except when a complete change in the capping location occurs. Alternatively, spreader barge 12 is stationary for a predetermined time during which the capping material is distributed, after which it will be repositioned and re-commence distribution. The thickness of the capping layer can range from about 1½ inches to about 9 inches, the thickness being dependent upon the sediment being capped and the capping material. Alternatively, the capping layer thickness can be less than 1½ inches or greater than 9 inches.
[0028] Now referring to FIGS. 5 and 6 , the spreading means 24 has a distribution chute 66 connected to the reservoir 29 , a broadcast spinner 68 , and an actuator 70 . Capping material flows from the reservoir 29 and through the chute 66 . After traveling down the chute 66 the capping material reaches the spinner 68 and is thereby broadcast into the pool 28 . The spinner 68 is substantially disc-shaped and comprises an axis connector 72 and a plurality of distribution fins 74 . The axis connector 72 has an aperture extending through it, which is mounted to the chute 66 . The actuator 70 is a hydraulic system which causes the spinner 68 to spin. As capping material reaches the spinning spinner 68 , the fins 74 act on the material to centripetally distribute the capping material within pool 28 . The fins 74 extend radially outward from connector 72 and extend outward and substantially perpendicular to a spinner surface 76 . As shown in FIG. 6 , an exemplary spinner 68 includes six fins 72 . In an alternative embodiment, the spinner 68 has one or more fins 74 .
[0029] Alternatively, more than one spreading means 24 is connected to the reservoir 29 . By example, two distribution means 24 can simultaneously distribute capping material into pool 28 . The spinners 68 for the respective distribution means 24 are configured to spin in opposite directions, on spinning in a clockwise direction and the second spinning in a counter clockwise direction. Preferably the spinner 68 rotating in a clockwise direction is positioned to the right of the second spinner 68 , which provides for a greater distribution area within pool 28 . In at least one embodiment, the spreading means 24 includes a barge metering hopper and belt scale (not shown) for measuring the distributed capping material, and at least one spinner 68 to distribute the capping material into the pool 28 . It is further contemplated that the size and shape of the spinners are selected based upon the capping material and desired rate of distribution.
[0030] Upon entering receiving means 18 , the capping material passes through shaker 20 , which includes a vibrating dewatering screen. In one embodiment, shaker 20 is capable of de-watering the slurry in excess of 200 tons per hour, based upon a screen measuring about 6 feet wide by about 16 feet long. Once the slurried capping material is dewatered, the clean transport water will be discharged overboard within pool 28 . The capping material rolls off the end of the screen into distribution means 24 . One exemplary distribution means 24 is an Epoke Sirius® (Epoke Inc., Stittsville, Ontario, Calif.) 6.5 cubic yard spreader. Alternatively, the distribution system includes a conveyor with a belt scale and a J.F. Brennan Co. hardened metal spreader. Spreader 24 is located on the bow of the spreader barge, broadcasting the de-watered capping material in a uniform pattern. Individual capping material particles will hit the water and fall through the water column at a reduced velocity, relative to bucket dumping, thereby covering the soft sediment with minimal disturbance. Alternately, granular capping material transported by barge can be offloaded by bucket and fed into the barge metering hopper for delivery to spreader 24 .
[0031] In an alternative embodiment, spreader pool 28 is about 35 feet long by about 12 feet wide. Spreader pool 28 is an area of open water surrounded by barriers, that allow capping material to be placed into a confined area. The barriers are preferably wall-like structures that extend above the barge 12 surface in a range of about 2 feet to about 5 feet high. By example, the barriers can be constructed of plywood, cement, or durable fabric. By confining the distribution of capping material, turbidity issues are minimized, which in turn reduces agitation of the contaminated sediment. Spreader 24 broadcasts capping material into spreader pool 28 over a measured duration after which the spreader barge is winched back a specific distance alongside template barge 14 . By example, the distribution rate can range from about 40 to about 60 cubic yards per hour and include 6-foot spreader barge 12 steps. Alternatively, spreader barge 12 can move continuously. In yet another alternative embodiment, the distribution rate can range from about 60 to about 100 cubic yards per hour. In yet another alternative embodiment, the distribution rate is less than 40 cubic yards per hour.
[0032] Capping material volume is measured to ensure accurate placement. A primary volume measurement is determined by the spreading means 24 , which includes a belt scale that provides real time capping distribution weights. The size and speed of the conveyor can determine the amount of material sent to spreader 24 . Once the required volume of capping material is placed, a signal is sent from the spreader unit to an alarm which sounds, alerting the plant operators that it is time to slide the spreader barge back another 6 feet. This system provides a continuous real time measurement of the volume of material being placed. Capping material volume can be metered onshore by conveyor 36 before being fed into slurry pipeline 16 . Compared to spreader barge spreader 24 , conveyor 36 metering will be used to determine volume measurements over longer periods of time, such as per day or on a weekly basis.
[0033] Both pre-and post-placement bathymetric surveys can be performed at the placement areas. The bathymetric vessel is designed for operations in shallow water. The vessel can be equipped with a single frequency fathometer, two real-time kinematic (RTK) Global positioning units, and one laptop computer unit. Post placement bathymetric surveys can be conducted within twenty-four to forty-eight hours after the barge places material over an area for quality control and confirmation of proper capping material distribution.
[0034] Control center 26 includes a computer which can utilize a variety of sub-aquatic analysis and measuring software. By example, the control center includes Dredgepack® (Hypack, Inc., Middletown, Conn.) software and Wonderware® (Invensys Systems, Inc., Lake Forest, Calif.) software. Dredgepack® can be used for positioning the spreader barge 12 , while Wonderware® can track the production of capping material distribution data collected. Wonderware® can integrate the use of a plurality, four by example, of sounding sensors located in each corner of the spreader pool. The sensors provide RTK GPS for real time measurement of the materials elevation and the targeted elevation and location. Dredgepack® can provide illustrated pre-cover placement elevation in two profile views, along with a top view. As the material is added to the waterway floor, the sensors will measure and record the elevation of the placed material. The operator will visually see this elevation change in both profile views and the top view will display the change. In addition to tracking capping progress on a daily basis, each placement area can be divided into capping units. The capping units can be designated to assist the management of large sediment capping operations. Alternatively, the spreader 24 utilizes a Real Time Kinematic (RTK) Global Positioning System (GPS) for capping material position and elevation tracking. The RTK GPS system uses satellite links to two spreader barge mounted receivers, a fixed location receiver with known coordinates, and a geometric method, referred to as tri-lateration, to determine the real-time position and elevation of a point on the spreader 24 to within 4 centimeters. This reference point is configured at the capping material discharge location. As the spreader barge 12 travels, turns, and rises and falls on the lake, the system continually updates the northing and casting coordinates, heading, and elevation of the capping material discharge position. The coordinates of the spreader 24 are sent to a survey software system such as DredgePack. This software system can provide a continuous log of coordinates and elevations for the capping material discharge location and can provide tools to help the operator accurately locate the spreader barge 12 at required coordinates. For each sand spreading location, Intouch® software system inserts capping material spreading information into a Microsoft SQL Server database. The capping material spreading information stored in the database includes the time and date, position coordinates, actual sand tonnage spread, sand density, spreading time duration, etc. for that spreading step. All of this information is available to be viewed via an Internet web browser in the form of a pre-developed report.
[0035] Now referring to FIGS. 7A and 7B , an alternative embodiment of spreader 24 is shown. Two spinners 68 are suspended above pool 28 by a spreader frame 76 . Chute 66 provides capping material to the spinners 68 , which rotate and distribute the material within pool 28 in a semi-circular pattern 78 (See FIG. 7B ). Each spinner 68 has a substantially flat top surface 80 which receives the capping material immediately prior to the capping material being distributed through centripetal forces. Spinners 68 are tilted toward each other, such that surface 68 is not parallel with pool 28 . The orientation of spinners 68 can be altered to affect the distribution pattern 78 . Orientation of spinners 68 can range from a substantially flat orientation to greater than 20 degrees pitch in any direction.
[0036] An alternative embodiment of spinner 68 is shown in FIG. 8 . Spinner 68 includes three fins 74 , an axis connector 72 , and a substantially flat top surface 80 . Each fin 74 is attached to surface 80 through an L-bracket 82 . Any suitable connection means known in the art, such as welding, can be used to connect surface 80 to L-bracket 82 , and fins 74 to L-bracket 82 . Spinner 68 can be manufactured from a variety of durable materials known in the art, including low-cost metals and metal alloys. Alternatively, fins 74 can be manufactured from higher-cost materials having greater durability, such as composites, precious and semi-precious metals, and metal alloys. By example, surface 80 can be manufactured from 420 stainless steel, while the fins are manufactured from titanium alloys.
[0037] Although the invention has been described in considerable detail, within the preceding specification and figures, the detail is for the purpose of illustration only, and not to be limited to the embodiments and illustrations previously described. Those skilled in the art will recognize that many variations and modifications can be made to the invention without departing from the spirit and scope as described by the following claims.
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Sub-aquatic sediment is covered with capping material by a capping system comprising a template barge and a spreader barge. While the spreader barge is distributing capping material, the template barge guides the spreader barge as it systematically moves over a pre-defined sediment capping region. The spreader barge comprises a spreader pool in which a broadcast spreader accurately and evenly distributes capping material within the pool, which then sinks to the sediment. The capping material is distributed with minimal disturbance to the sediment.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to apparatus and method for recycling oil laden waste or used materials, and in particular to the reclamation of used or spent oil filters.
2. Prior Art
Oil filters as used in most internal combustion engines are used to clean the oil as it circulates therethrough. A typical oil filter is made up of a metal canister within which some form a porous media or paper like materials are therein contained. In addition to the metal and porous media a typical oil filter also contains an elastomeric seal and, in some cases, plastics that are used within the filter. Because oil filters need to be changed often the disposal of the filters has become a major environmental problem. Recycling the filter is not an easy task, and thus, most of such waste has been heretofore disposed in landfills. Since the oil filter is not biodegradable this presents additional environmental problems. As a result, government regulations now require some form of environmental disposal. The lubrication service businesses and others are therefore faced with no easy method of recycling or disposing of the oil filters.
Many of the prior art oil filter recycling operations do not consider the total recycling possibilities of the products that go to make up the filter. Many systems have as their prime objective simply to remove or clean the oil from the steel filter container and then dispose in some manner the paper filter medium. In many instances this wastes a large percentage of the oil simply burned in after burners.
U.S. Pat. No. 5,298,079 of E. Park Guymon has proposed a process for removing oil from the oil filters by washing the oil filters while simultaneously crushing the metal outer case. This process involves the effective removal of the residual oil from the water, and cleaning the washed water with surfactants for recycling.
U.S. Pat. No. 5,135,176 issued to John Barber teaches a method of recycling oil filters by first shredding the filter, which is subsequently placed in an oven or other form of thermal unit wherein the shredded metal particles are separated from the ash and recycled.
U.S. Pat. No. 5,366,165 of Raymond P. Jackman describes a system for recycling and treating used oil filters by a shredding and washing procedure.
SUMMARY OF THE INVENTION
This invention is an advancement in the art of recycling and reclaiming oil laden waste materials, in particular used oil filters, utilizing combustion methods and apparatus having a much greater overall efficiency. Accordingly, it is an object of this invention to provide an apparatus and method for recycling of oil laden hazardous waste material, and in particular internal combustion engine oil filters to provide environmentally safe reuse and disposition of the waste materials, that is not available with the prior art apparatus methods.
The specific method for removing and recovering oil from oil contained waste products, e.g., oil filters, involves a first step of heating the products in a fuel fed primary combustion chamber under reducing i.e., less than stoichiometric air conditions. A plurality of stepped platforms are provided within the chamber in which the oil containing waste products enter from an upper platform and are tumbled to a next adjacent lower platform, etc., synchronously. The changed position of the products, while in the environment combustion chamber, permits additional drainage of oil from the products. The oil products are removed from the primary combustion chamber as liquid oil and as oil vapor. The liquid oil is recovered and removed from the primary combustion chamber. The combustion residue enters a quench pit within which an endless conveyor system conveys the waste solid or metal products in one direction while conveying the remaining smaller residue, ash, etc. in the other direction. The oil in vapor form is then introduced from the primary combustion chamber into an indirect heat exchanger for cooling and condensing and recovering the oil from the vapor. The remaining products of combustion are then passed into a secondary combustion chamber being operated under excess stoichiometric conditions to complete and create clean burning which is then exhausted from the secondary combustion zone.
A further object of this invention is to efficiently recycle and utilize all the components of the oil contaminated waste materials. The oil free steel has prime scrap value to steel mills while the oil can become reprocessed automotive oil or converted into marine fuel, asphalt processing, or other oil bearing products. The residue or ash resulting from the combustion can be used as a concrete extender which strengthens concrete by giving it added working time. The heat generated in a secondary chamber can also be used to heat liquids i.e., water to create steam for plant cleanup or other functions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side cross sectional view depicting the apparatus and method of this invention.
FIG. 2 is an elevational end view, partly in section taken along the line 2--2 of FIG. 1.
FIG. 3 is a sectional view, taken along the line of 3--3 of FIG. 1.
FIG. 4 is an enlarged sectional view of that portion shown circled in FIG. 1.
FIG. 5 is a schematic diagram of the process of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Whereas, the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.
WASTE PRODUCTS:
This invention is more aptly directed to the recycling of used internal combustion oil filters, but is also applicable for use in recovering oil from other oil laden products, such as oily rags, oil booms, oil pads, Oil-Dry®, grease and other waste and used products containing significant amounts of oil.
THE APPARATUS:
The apparatus and system of this invention consist of 5 major components. Referring to FIG. 1 these are a hydraulic loader generally designated by the numeral 10. A primary combustion chamber 12, a quench pit and conveying system 14, oil vapor reclamation and heat exchange chamber 16 and secondary combustion chamber and stack 18.
HYDRAULIC LOADER:
The hydraulic loader system is a standard form of loading device used by many furnace manufacturers to load materials thereinto. The loader is connected to a hydraulic control means 30 which operates a piston 32 which directs waste products entering through bin 34 into the chute or cylinder 36 where the products are then sealably pushed into the furnace. The hydraulic control system 30 includes a feed timer for sequencing the operation of the hydraulic loader and the individual stepped hydraulic push members 40, 42, 44, and 46. The hydraulic loader system has two functions, i.e., move the waste product material from the bin 34 into the chute 36 onto platform 50. At the same time or alternately the waste products on 50 are pushed and tumbled onto subsequent platforms 52, 54, and 56 upon the timed sequence to operate hydraulic pistons 40, 42, 44, and 46.
PRIMARY CHAMBER:
The primary chamber 12 is adapted to receive the waste oil products from the loader, which is slowly conveyed sequentially from platform 50, to platform 52, to platform 54, to platform 56, and thence to the quench pit outlet 14. The quench pit is filled to a water level 60 and is adapted to receive the larger waste products 48 in which the oil therefrom has been substantially removed either in liquid form or in vapors form 62. The primary chamber has one plurality of burners 64, 66, and 68 which maintain the primary chamber at temperature ranges of 800 to 1,000° F. (427-538° C.) under less than stoichiometric air settings. This `starved air` system is thus, designed to perform two functions: lower the viscosity of the oil so it will drain from the products, and volatize (but not burn) the oil into a vapors 62 which then carried to the oil condensing or reclamation chamber 16. Suitable controls provide regulation of the primary chamber, such as, programmable controllers and control of the gas/air mixture to the burner to maintain the aforesaid conditions. The first area of the primary chamber is a preheating zone 64 which elevates the product up to about 400° F. (205° C.). The preheat temperature dramatically lowers the viscosity of the oil, which drains into oil traps 70 located in the floor of each platform 50, 52, 54 and 56. FIG. 4 is an enlarged view that depicts one form of oil drain in platform 54 wherein, the oil is carried via passageway 72 into the collection conduit 70 which is then drained from the system to an outside collection or storage. (See FIG. 3)
QUENCH PIT:
The quench pit 14 is normally transverse to the longitudinal flow of waste products, being filled with a quench liquid 60, e.g., water. As shown in FIG. 2 an endless conveyor system generally designated by the numeral 80 includes a belt 82 of stainless steel grating or mesh having a plurality of spaced flights baffles 84. These baffles are, when moving in the direction shown, adapted to pickup the processed products i.e., oil filters, pads, rags, etc., which have reached the quench. By this time substantially all of the oil has been removed both as liquid and/or vapor, the latter transferred to the oil reclamation and condensing chamber 16. The quench pit prevents any gases to escape through this area. As the metal filters and other products fall into the quench pit, the larger products are captured on the top level of the conveyor and exit under the water seal to a storage or into a container 88 for transport to a steel mill. The lighter ash and residue products will filter through the water seal, the top of the conveyor mesh 82 dropping to the bottom of the pit. The elevated baffles or flights 84 then serve as rakes as the flights return across the bottom of the pit to the other side, where the ash is carried up an inclined trough 90 to storage and/or containers where the ash products can then be shipped for other uses e.g., as a concrete strength or retarding additive.
OIL RECLAMATION CHAMBER:
Oil reclamation chamber 16 is adapted to receive, via conduit 100, the volatilized oil vapors 62 from the primary chamber 12. The reclamation chamber is essentially a heat exchanger having a central baffle therein 102 which is angularly directed within the serpentine coils 104 of the reclamation chamber for drainage purposes. Condensed oil vapors are removed from the chamber via conduits 106. The temperature of the vapors are cooled to below he recondensing point of the oil, i.e., about 600° F. (318° C.) as the oil vapor laden gases are caused to wind their way through the water cooling tubes 104. The remaining oil vapors then exit to the secondary chamber 18 via opening 110.
SECONDARY CHAMBER:
The purpose of the secondary chamber 18 is to destroy any remaining unburned fuel or other compounds remaining in the gas stream and can become the ultimate control over the production (or charging) capacity of the whole system. As such, the chamber is preferably operated under stoichiometric or greater than stoichiometric air conditions utilizing one or more burners 120. The secondary chamber is designed to hold the products of combustion at approximately 1800° F. (990° C.) for approximately two or three seconds with the gas stream flowing along one conduit 121 towards the end of the chamber 122 where it is diverted through opening 124 and reversed back through the return conduit 123 ultimately exiting via exhaust 126.
The secondary chamber is initially fired up to temperature using natural gas or some other fossil fuel, however, once the desired temperature is reached, and the remainder of the system comes on line, the secondary chamber can become thermally self supporting. Normally, 30-60% of the process gas stream will contain enough fuel, as oil vapor, along with the proper air mixture to maintain a desired secondary chamber temperature. If the secondary chamber starts dropping in temperature, the operator may either increase the vapors entering the primary chamber and/or lower the reclamation chamber cooling water, or fire up the burner 120. The secondary chamber will typically operate with 10% free oxygen in the gas stream, an oxygen monitor, not shown, is used as to monitor the gas stream at all times therein. If the oxygen level drops to a given amount, e.g., under 7%, or other desired set point, several control functions can begin. At 7% oxygen, the loader 10 can be locked out and the primary chamber air modulated down. If the oxygen level returns to 8% or higher, then the operation will continue normally. However, if the oxygen level continues down, e.g., to 6%, or less, then additional air is supplied into the secondary chamber until the desire level has been achieved. In an emergency, if the oxygen level continues to drop e.g., below 4% and remains at this level for several seconds a water spray system is adapted to activate quenching the activity in the primary chamber 12.
Other controls insure clean exhaust gases by regulating the charging rate of the system if the fuel rate exceeds 8 MM/BTU/Hr.
The secondary chamber is to maintain a minimum temperature of 1800° F. If the temperature in the secondary chamber begins to rise and exceeds the minimum by, for example, 100° F., then the primary chamber air is reduced and a hydraulic loader 10 locked out. If the temperature reduces back to the minimum, normal operation can continue. However, if the secondary chamber temperature continues to rise over 150° F. above the minimum set point, then emergency air is caused to enter the secondary chamber. If the system does not come under control within 60 seconds, the emergency water spray quench will deploy. Thus, the water spray system will continue to operate until all of the following are satisfied;
The oxygen level rises over 4%;
The secondary chamber temperature is under the 150° F. over temperature; and
The emergency secondary chamber air is off.
In another embodiment of the invention, the heat in the secondary chamber may be utilized in conjunction with a heat exchanger 140 (see FIG. 5) as an auxiliary heat source such as to make steam or for other uses.
In the operation of the system disclosed, waste oil products, such as oil filters and other adsorbents, including the but not limited to oil booms, oily rags, pads, and Oil-Dri® are loaded into the loader 36. The products are then charged into the primary furnace chamber 64 at a scheduled feed rate controlled by the hydraulic system/timer 30. After the ram 32 is withdrawn to the position shown, the unit automatically reseals. Within the primary chamber are a plurality of platforms (four shown), following the initial charging station, with the product moving down the platforms by the action of the floor sweep rams 40, 42, 44, and 46. Each of the platforms include a plurality of oil collection drains 70, as shown enlarged in FIG. 4, which carry the oil outside the furnace. In the early phase of the process as the oil heats up it thins and runs into the collection drains 70. Approximately 20-30% of the oil trapped in the filters and adsorbents are collected through gravity drains 70. As the product charge progresses down the platforms, closer to burners 65, 66 and 68, the primary chamber temperature increases. The remaining oil begins to vaporize and is drafted towards the recycle chamber 16. Vaporization takes place at approximately 500-1000° F. (260-538° C.) typically at about 800° F. (427° C.). From the time the charge products enter the primary combustion chamber, it will be exposed to the heat for approximately 3-6 hours. By the time the product charge reaches the final tier, it should be oil free and consist of only clean steel, fly ash and/or other solid products of combustion. These products are slowly pushed into the quench tank 14 containing the conveying device described, as best shown in FIG. 2, for removal outside the system. The oil vapors 62 and other products of combustion proceed to the recycling chamber 16 where the temperature of the oil laden exhaust is lowered to approximately 200-400° F. (93-204° C.). Oil then recondenses within the recycled chamber and runs to a collection point at the bottom of the recycled chamber wherein the oil is removed via conduits 106. The temperature of the recycled chamber 16 is controlled to allow sufficient vaporized fuel to sustain the secondary chamber 18 operating at a minimum of 1800° F. (982° C.). As stated, the secondary chamber 16 can also be used as a process heater or as a boiler, dryers or other use.
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A system for treating oil laden used products, e.g., oil filters to achieve complete recycle of the products. The used products are heated in a primary combustion zone under reducing conditions to lower the viscosity of the oil for removal and to create oil in vapor form. The oil vapor is passed to a reclamation chamber where oil is condensed and removed. The remaining vapors are led to a secondary combustion chamber under greater than stoichiometric conditions to produce clean exhaust.
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TECHNICAL FIELD
[0001] The present invention relates to a battery pack including a battery cell stack of secondary batteries which can be charged and discharged.
BACKGROUND ART
[0002] With remarkable development of information technology (IT), a great variety of portable information communication devices has been popularized. As a result, in the 21 st century, we are moving toward a ubiquitous society in which high-quality information service is possible regardless of time and place.
[0003] Meanwhile, lithium secondary batteries are very important to extend such a ubiquitous society. Specifically, lithium secondary batteries, which can be charged and discharged, have been widely used as an energy source for wireless mobile devices. In addition, lithium secondary batteries have also been used as an energy source for electric vehicles and hybrid electric vehicles, which have been proposed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuel.
[0004] As devices, to which the lithium secondary batteries are applicable, are diversified as described above, the lithium secondary batteries have also been diversified such that the lithium secondary batteries can provide powers and capacities suitable for devices to which the lithium secondary batteries are applied. In addition, there is a strong need to reduce the size and weight of lithium secondary batteries.
[0005] For example, small-sized mobile devices, such as mobile phones, personal digital assistants (PDAs), digital cameras, and laptop computers, use one or several small-sized, lightweight battery cells for each device according to the reduction in size and weight of the corresponding products.
[0006] On the other hand, middle or large-sized devices, such as electric bicycles, electric motorcycles, electric vehicles, and hybrid electric vehicles, use a middle or large-sized battery module (middle or large-sized battery pack) having a plurality of battery cells electrically connected with each other because high power and large capacity are necessary for the middle or large-sized devices. The size and weight of the battery module is directly related to an accommodation space and power of a corresponding middle or large-sized device. For this reason, manufacturers are trying to manufacture small-sized, lightweight battery modules.
[0007] A cylindrical battery cell, a prismatic battery cell, and a pouch-shaped battery cell, which are classified based on their shapes, are used as a unit cell of a battery module or battery pack, Especially, the pouch-shaped battery cell, which can be stacked with high integration, has a high energy density per weight, and is inexpensive, has attracted considerable attention.
[0008] FIGS. 1A and 1B are exploded perspective views typically showing the general structure of a conventional representative pouch-shaped secondary battery.
[0009] Referring to FIG. 1A , a pouch-shaped secondary battery 10 includes an electrode assembly 20 having pluralities of electrode tabs 21 and 232 protruding therefrom, two electrode leads 30 and 31 respectively connected to the electrode tabs 21 and 232 , and a battery case 40 to receive the electrode assembly 20 in a sealed state such that portions of the electrode leads 30 and 31 are exposed outward from the battery case 40 .
[0010] The battery case 40 includes a lower case 42 having a depressed receiving part 41 , in which the electrode assembly 20 is located, and an upper case 43 to cover the lower case 42 such that the electrode assembly 20 is sealed in the battery case 40 . The upper case 43 and the lower case 42 are connected to each other by thermal welding in a state in which the electrode assembly is mounted therein to form an upper end sealed part 44 , side sealed parts 45 and 46 , and a lower end sealed part 47 .
[0011] As shown in FIG. 1A , the upper case 43 and the lower case 42 may be configured as separate members, As shown in FIG. 1B , on the other hand, one end of the upper case 43 may be integrally formed at a corresponding end of the lower case 42 such that the upper case 43 and the lower case 42 may be hingedly connected to each other.
[0012] Also, as shown in FIGS. 1A and 1B , the pouch-shaped battery cell is configured to have a structure in which electrode terminals constituted by the electrode tabs and the electrode leads are formed at one end of the electrode assembly. However, a pouch-shaped battery cell configured to have a structure in which electrode terminals are formed at opposite ends of an electrode assembly may also be manufactured using the above method.
DISCLOSURE
Technical Problem
[0013] As shown in FIGS. 1A and 1B , a pouch-shaped battery cell is generally manufactured so as to have an almost rectangular parallelepiped structure. A plurality of such pouch-shaped battery cells is stacked to constitute a battery pack having a rectangular parallelepiped structure.
[0014] However, a device, to which the battery cell or the battery pack having the rectangular parallelepiped structure is applied, is not generally formed in the shape of a rectangular parallelepiped. For example, sides of a smartphone are curved to improve grip.
[0015] In a case in which the battery cell or the battery pack having the rectangular parallelepiped structure is mounted in a device designed so as to have such curved portions, space utilization of the device may be deteriorated.
[0016] That is, the curved portions of the device have, dead spaces, in which the battery cell or the battery pack cannot be mounted. Eventually, such dead spaces lower the capacity of the device per volume.
[0017] Therefore, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a battery pack wherein the capacity of a device per volume is maximized.
Technical Solution
[0018] In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a battery pack including two or more battery cells stacked in a height direction on the basis of a plane, wherein one or more battery cells have the same size as or different sizes than one or more other battery cells and the battery cells having different sizes are stacked to form a one or more stair-like structure having a width and a height.
[0019] In the above description, the plane means any plane. That is, the plane may be the ground or a plane perpendicular to the ground. Consequently, the battery cells may be stacked on the ground in the height direction, Alternatively, the battery cells may be stacked on the plane perpendicular to the ground in the height direction.
[0020] Hereinafter, the plane may be referred to as the ground for ease of understanding. In this case, the height direction from the plane may be referred to as an antigravity direction, and the direction opposite to the height direction may be referred to as a gravity direction.
[0021] For example, “the battery cells are stacked in the height direction on the basis of the plane” in the above description may mean that the battery cells may be stacked from the ground in the gravity direction and/or in the antigravity direction,
[0022] Consequently, the stacked direction of the battery cells may be the gravity direction and/or in the antigravity direction.
[0023] In a case in which the battery cells are stacked in the height direction and in the direction opposite to the height direction, i.e. in opposite directions, on the basis of the plane, the battery cells stacked in the height direction on the basis of the plane and the battery cells stacked in the direction opposite to the height direction on the basis of the plane may be arranged in a symmetrical fashion or in an asymmetrical fashion.
[0024] The battery pack may be configured to have a structure in which two or more battery cells are stacked, and electrode terminals of the battery cells are electrically connected to each other. In this case, at least one selected from among a total length, a total width, and a total height of one of the electrode terminals may be different from that of the other electrode terminal or the total length, the total width, and the total height of one of the electrode terminals may be equal to those of the other electrode terminal. Also, the battery cells may be stacked such that the electrode terminals are stacked in an overlapped state to electrically connect the electrode terminals to each other.
[0025] The battery pack may include two or more battery cells. In this case, the two or more battery cells may have different sizes. Alternatively, one of the battery cells may have a size different from that of the other battery cells having the same size.
[0026] Also, the battery pack may include a combination of two or more battery cells (A) having the same size and two or more battery cells (B) having the same size, the size of the battery cells (B) being different from that of the battery cells (A). Alternatively, the battery pack may include a combination of two or more battery cells (A) having the same size, two or more battery cells (B) having the same size, the size of the battery cells (B) being different from that of the battery cells (A), and two or more battery cells (C) having the same size, the size of the battery cells (C) being different from those of the battery cells (A) and the battery cells (B).
[0027] In order to form the stair-like structure, the battery pack according to the present invention may include one or more battery cells have different widths and/or lengths. Battery cells having different sizes may be battery cells having different widths and/or lengths.
[0028] The stair-like structure has a width and a height. The width of the stair-like structure may correspond to the difference between the widths or the lengths of the stacked battery cells, and the height of the stair-like structure may be the sum of heights of stairs. The height of each stair may correspond to the height of each of the stacked battery cells.
[0029] The stair-like structure may have (i) the same stair height and different widths or (ii) different widths and stair heights,
[0030] Specifically, a plurality of battery cells having the same length, the same stair height, and different widths, a plurality of battery cells having the same width, the same stair height, and different lengths, or a plurality of battery cells having different widths, lengths, and stair heights may be stacked to form a stair-like structure.
[0031] The width and/or stair height of the stair-like structure may be changed based on the radius of curvature of a device in which the battery pack is mounted.
[0032] Specifically, in the battery pack according to the present invention, the stair-like structure may be configured such that the stair height is gradually decreased from the lower end to the upper end of the stair-like structure in the height direction on the basis of the plane. The stair-like structure may be configured such that the stair height is gradually increased from the lower end to the upper end of the stair-like structure in the height direction on the basis of the plane. The stair-like structure may be configured such that the width is gradually increased from the lower end to the upper end of the stair-like structure in the height direction on the basis of the plane. The stair-like structure may be configured such that the width is gradually decreased from the lower end to the upper end of the stair-like structure in the height direction on the basis of the plane. The stair-like structure may be configured such that both the width and the stair height are gradually increased or decreased from the lower end to the upper end of the stair-like structure in the height direction on the basis of the plane.
[0033] A region at which the stair-like structure is formed is not particularly restricted. Specifically, the stair-like structure may be formed at an electrode terminal non-formation region or an electrode terminal formation region. Alternatively, the stair-like structure may be formed at both the electrode terminal non-formation region and the electrode terminal formation region.
[0034] In a case in which the stair-like structure is formed at both the electrode terminal non-formation region and the electrode terminal formation region, the stair-like structure may be formed in the shape of a frustum of a quadrangular pyramid or a frustum of an octagonal pyramid. The frustum of the octagonal pyramid may be a symmetric frustum of an octagonal pyramid or an asymmetric frustum of an octagonal pyramid.
[0035] A system component of a device, in which the battery pack is mounted, is located at the stair-like structure.
[0036] Each of the battery cells may be a prismatic battery cell, a cylindrical battery cell, or a pouch-shaped battery cell. However, the shape of the battery cells according to the present invention is not particularly restricted, Consequently, the battery pack according to the present invention may include a structure in which the battery cells are stacked in a mixed fashion.
[0037] Hereinafter, each of the battery cells may be referred to as a pouch-shaped battery cell configured to have a structure in which a stack of cathodes, separators, and anodes, i.e. an electrode assembly, is received in a cell case, the cell case is sealed by thermal welding after the electrode assembly is impregnated with an electrolyte for ease of understanding. However, the present invention is not limited thereto.
[0038] The plate-shaped battery cell may be a pouch-shaped battery cell configured to have a structure in which a stack of cathodes, separators, and anodes, i.e. an electrode assembly, is received in a cell case, the cell case is sealed by thermal welding in a state in which a cathode terminal and an anode terminal protrude outward from the cell case after the electrode assembly is impregnated with an electrolyte.
[0039] The cell case may include a receiving part to receive the electrode assembly and a sealed part formed around the receiving part by thermal welding. According to circumstances, the sealed part may be bent toward the receiving part.
[0040] In a concrete example, the pouch-shaped battery cell may be a first type pouch-shaped battery cell having a circular structure in plane, a polygonal structure in plane, a polygonal structure in plane, at least one corner of which is curved, or a polygonal structure in plane, at least one side of which is curved, and configured to have a structure in which the cathode terminal and the anode terminal are formed at one end of the battery cell.
[0041] In another concrete example, the pouch-shaped battery cell may be a second type pouch-shaped battery cell having a circular structure in plane, a polygonal structure in plane, a polygonal structure in plane, at least one corner of which is curved, or a polygonal structure in plane, at least one side of which is curved, and configured to have a structure in which the cathode terminal and the anode terminal are formed at one end of the battery cell and the other end of the battery cell opposite to one end of the battery cell, respectively.
[0042] In a further concrete example, the pouch-shaped battery cell may be a third type pouch-shaped battery cell having a circular structure in plane, a polygonal structure in plane, a polygonal structure in plane, at least one corner of which is curved, or a polygonal structure in plane, at least one side of which is curved, and configured to have a structure in which the cathode terminal and the anode terminal are located at adjacent sides of the battery cell.
[0043] The first type pouch-shaped battery cell, the second type pouch-shaped battery cell, and the third type pouch-shaped battery cell may be electrically connected to one another while being stacked in a mixed fashion.
[0044] The electrode assembly is configured to have a structure including a cathode, an anode, and a separator disposed between the cathode and the anode. The electrode assembly may be a stacked type electrode assembly, which is manufactured by sequentially stacking a cathode plate, a separator plate, and an anode plate such that the separator plate is disposed between the cathode plate and the anode plate, a wound type electrode assembly, which is manufactured by sequentially stacking a sheet type cathode, a sheet type separator, and a sheet type anode and winding the sheet type cathode, the sheet type separator, and the sheet type anode such that the sheet type separator is disposed between the sheet type cathode and the sheet type anode, or a combination (stacked/folded) type electrode assembly, which is manufactured by arranging one or more polarized bodies selected from a group consisting of a cathode plate, an anode plate, and a stacked type electrode assembly on a sheet type separator and winding or folding the sheet type separator. The stacked/folded type electrode assembly may be manufactured using two or more sheet type separators.
[0045] Meanwhile, in order to achieve stable coupling between the battery cells stacked in the height direction on the basis of the plane, the battery pack may further include an adhesion means or a bonding means to couple the battery cells.
[0046] The adhesion means or the bonding means is not particularly restricted so long as the coupling between the battery cells is easily achieved. For example, the adhesion means or the bonding means may be an adhesive, a bonding agent, a double-sided adhesive tape, or a double-sided bonding tape.
[0047] According to circumstances, a spacer may be disposed between battery cells having different sizes and a system component of a device may be located at a portion of the spacer.
[0048] In the above structure, the spacer may be formed in a frame shape corresponding to outer circumferential regions of the battery cells facing each other.
[0049] An adhesion means or a bonding means of a predetermined thickness to couple the battery cells may be applied to the top and the bottom of the spacer or a double-sided adhesive or bonding tape may be attached to the top and the bottom of the spacer such that the spacer is easily mounted to a corresponding top and a corresponding bottom of the battery cells. Also, the battery cells may be fixed in position using ultraviolet (UV) gel or UV glue in a state in which the battery cells are stacked. The spacer may be a heat sink.
[0050] In accordance with another aspect of the present invention, there is provided a device comprising the battery pack with the above-stated construction as a power source.
[0051] An example of the device, for which the battery pack according to the present invention is used, may be selected from among a mobile phone, a portable computer, a smartphone, a smart pad, a laptop computer, a light electronic vehicle (LEV), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage unit. However, the device is not limited thereto.
[0052] The structure of each device and a method of manufacturing each device are well known in the art to which the present invention pertains, and therefore, a detailed description thereof will be omitted.
Effects of the Invention
[0053] As is apparent from the above description, the battery pack according to the present invention includes a stair-like structure changed based on the radius of curvature of a device. Consequently, the present invention has an effect of increasing the capacity of the device per volume utilizing a dead space defined in the device unlike a conventional battery pack.
[0054] In addition, a system component of the device, in which the battery pack is mounted, is located at the stair-like structure, Consequently, the dead space of the device is further utilized.
DESCRIPTION OF DRAWINGS
[0055] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0056] FIGS. 1A and 1B are exploded perspective views showing a conventional representative pouch-shaped secondary battery;
[0057] FIG. 2 is a perspective view showing a battery pack, including pouch-shaped battery cells each having angled corners, according to an embodiment of the present invention;
[0058] FIG. 3 is a perspective view showing a battery pack including pouch-shaped battery cells each having a curved corner as a modification of the battery pack shown in FIG. 2 ;
[0059] FIGS. 4 and 5 are perspective views showing a battery pack according to another embodiment of the present invention; ,
[0060] FIG. 6 is a view typically showing a method of manufacturing the battery pack shown in FIGS. 4 and 5 ;
[0061] FIG. 7 is a perspective view showing a battery pack according to another embodiment of the present invention;
[0062] FIG. 8 is a sectional view taken along line A-A of FIG, 2 ;
[0063] FIGS. 9 to 12 are views typically showing the battery pack according to the embodiment of the present invention using the sectional view of FIG. 8 ;
DETAILED DESCRIPTION OF THE INVENTION
[0064] Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted, however, that the scope of the present invention is not limited by the illustrated embodiments,
[0065] In FIGS. 2 to 7 , there are shown battery packs configured such that three pouch-shaped battery cells 110 , 120 , and 130 having diffident lengths are stacked to form a stair-like structure at an electrode terminal non-formation region 150 .
[0066] Referring to FIG. 2 , there is shown a battery pack 200 configured to have a structure in which three first type pouch-shaped battery cells 110 , 120 , and 130 are stacked in the height direction on the basis of a plane parallel to the ground. A stair-like structure is formed at an electrode terminal non-formation region 150 .
[0067] Also, electrode terminals of the pouch-shaped battery cells 110 , 120 , and 130 are connected to each other by welding in a stacked state to form electrode terminal connection parts 140 and 141 . The electrode terminal connection parts 140 and 141 may be connected in series or in parallel. The electrode terminal connection parts 140 and 141 are formed at one side on the basis of a virtual center line C-C of the battery cell 130 .
[0068] Referring to FIG. 3 , there is shown a battery pack 200 including three first type pouch-shaped battery cells 110 , 120 , and 130 each having a curved corner. The radius of curvature of the curved corner may be properly adjusted based on a curved device.
[0069] Only one corner of each of the battery cells 110 , 120 , and 130 is curved. However, each of the battery cells 110 , 120 , and 130 may have two or more curved corners based on the shape of a curved device, which falls within the scope of the present invention.
[0070] Referring to FIG. 4 , there is shown a battery pack 200 configured to have a structure in which three second type pouch-shaped battery cells 110 , 120 , and 130 are stacked in the height direction on the basis of a plane parallel to the ground. In the same manner as in FIG. 2 , a stair-like structure is formed at an electrode terminal non-formation region 150 . Electrode terminal connection parts 140 and 141 may be connected in series or in parallel. According to circumstances, both or one of the electrode terminal connection parts 140 and 141 may be formed at one side on the basis of a virtual center line (not shown) of the battery cell 130 .
[0071] A battery pack shown in FIG. 5 is identical to the battery pack shown in FIG. 4 except that an electrode terminal, i.e. a cathode terminal or an anode terminal, of a battery cell 130 , which is stacked at the lowermost end is bent. The battery pack of FIG. 4 may be a small-sized battery pack which may be used as a power source of a device, such as a mobile phone, and the battery pack of FIG. 5 may be a middle or large-sized battery pack which may be used as a power source of an electric vehicle.
[0072] FIG, 6 is a view typically showing a method of manufacturing the battery pack 200 shown in FIGS. 4 and 5 . As shown in FIG. 6 , the battery cell 120 is folded as indicated by an arrow such that the battery cell 120 is stacked on the battery cell 130 , and then the battery cell 110 is folded as indicated by an arrow such that the battery cell 110 is stacked on the battery cell 120 . As a result, the battery cells 110 , 120 , and 130 are folded in a Z shape.
[0073] Referring to FIG. 7 , there is typically shown a battery pack 200 configured to have a structure in which three third type pouch-shaped battery cells 110 , 120 , and 130 , each of which has an angle of 90 degrees between a cathode terminal and an anode terminal, are stacked.
[0074] The battery pack of FIG. 7 is identical to the battery pack of FIGS. 2 and 4 except that the third type pouch-shaped battery cells 110 , 120 , and 130 are stacked.
[0075] FIG. 8 is a vertical sectional view taken along line A-A of FIG. 2 .
[0076] Referring to FIG. 8 , it can be clearly seen that the battery pack 200 , in which the three battery cells 110 , 120 , and 130 having the same height and different lengths are stacked, has a stair-like structure formed at the electrode terminal non-formation region.
[0077] Also, referring to FIG. 8 , it can be seen that the stair-like structure of the battery pack 200 is configured such that the height is gradually decreased and the width is gradually increased from the lower end to the upper end of the stair-like structure.
[0078] FIG. 9 is a sectional view showing a battery pack in which battery cells 110 , 120 , and 130 having different heights and lengths are stacked unlike FIG. 8 .
[0079] A straight line L 2 -L 2 tangent to the battery cell 130 having the greatest height and length and to the battery cell 120 , stacked on the battery cell 130 , having a height and a length less than those of the battery cell 130 is inclined at a predetermined angle to a central axis H-H.
[0080] Also, a straight line L 1 -L 1 tangent to the battery cell 120 and to the battery cell 110 , stacked on the battery cell 120 , having a height and a length less than those of the battery cell 120 is inclined at another predetermined angle to the central axis H-H.
[0081] It can be seen from FIG, 9 that in the battery pack 200 , in which the three battery cells 110 , 120 , and 130 having different heights and lengths are stacked, the angle between the straight line and the central axis is gradually increased from the lower end to the upper end of the stair-like structure, That is, the angle between the straight line L 1 -L 1 and the central axis H-H is greater than that between the straight line L 2 -L 2 and the central axis H-H.
[0082] FIG. 10 typically shows a battery pack 200 configured to have a structure in which three battery cells 130 having the same length are located at the lowermost end, two battery cells 120 having the same size and a length less than that of the battery cells 130 are located on the battery cells 130 , and a battery cell 110 having a length less than that of the battery cells 120 is located at the uppermost end.
[0083] Referring to FIG. 10 , an angle between a straight line L 1 -L 1 and a central axis H-H is greater than that between a straight line L 2 -L 2 and the central axis H-H in the same manner as in FIG. 9 .
[0084] In the above description, the battery packs including battery cells having different lengths and/or heights have been described in detail with reference to FIGS. 2 to 10 . However, it can be easily understood from the above description that the present invention may be applied to a battery cell stack in which battery cells having different widths and/or heights are stacked or a battery cell stack in which battery cells having different widths, lengths, and heights are stacked.
[0085] FIG. 11 is a vertical sectional view typically showing a battery pack configured to have a structure in which battery cells 110 , 120 , and 130 are stacked in the shape of a frustum of a quadrangular pyramid, and FIG. 12 is a vertical sectional view typically showing a battery pack configured to have a structure in which battery cells 110 , 111 , 120 , 121 , 130 , and 131 are stacked in the shape of a frustum of an octagonal pyramid.
[0086] In the battery pack of FIG. 11 formed in the shape of the frustum of the quadrangular pyramid and the battery pack of FIG. 12 formed in the shape of the frustum of the octagonal pyramid, stair-like structures may be formed at both an electrode terminal formation region and an electrode terminal non-formation region. That is, in the battery pack of FIG. 11 formed in the shape of the frustum of the quadrangular pyramid and the battery pack of FIG. 12 formed in the shape of the frustum of the octagonal pyramid, the battery cells having different widths and lengths are stacked.
[0087] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
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Disclosed herein is a battery pack including secondary batteries which can be charged and discharged. The battery pack is configured such that secondary batteries having different sizes are stacked to form a stair-like structure having a width and a height.
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FIELD OF THE INVENTION
[0001] An electric light display assembly comprised of a rod, a lamp retaining device, a connector, and electric lamps.
BACKGROUND OF THE INVENTION
[0002] U.S. Pat. No. 5,700,083 of Boechel describes and a device for displaying electric lamps in a window frame, the device comprising rod means, lamp retaining means, end members, and electric lamps. The entire disclosure of this United States patent is hereby incorporated by reference into this specification.
[0003] The rod means of U.S. Pat. No. 5,700,083 includes a first intermediate member having a length nearly equal to but somewhat less than a first distance between spaced apart surfaces of the window frame.
[0004] The rod means of U.S. Pat. No. 5,700,083 also includes a plurality of first lamp retaining means provided as clip means at spaced intervals along the length of the first intermediate members.
[0005] The rod means of U.S. Pat. No. 5,700,083 also includes first end members provided at opposed terminal ends of the first intermediate member to fit between the spaced apart surfaces defining the first distance of the window frame.
[0006] In addition to such rod means, the display device of U.S. Pat. No. 5,700,083 also includes a plurality of electric lamps supported by respective ones of the plurality of lamp retaining means.
[0007] The device of U.S. Pat. No. 5,700,083 has met with a fair degree of commercial success. However, such device is not readily adaptable to produce a display assembly which will fit in a large variety of differently sized windows or doors or frames. It is an object of this invention to provide a connector which will allow the device of U.S. Pat. No. 5,700,083 to fit in a substantially infinite number of different configurations.
SUMMARY OF THE INVENTION
[0008] In accordance with this invention, there is provided an electric light display assembly comprised of a first rod means described in U.S. Pat. No. 5,700,083 (or a derivation thereof), a second rod means described in U.S. Pat. No. 5,700,083, a multiplicity of electric lamps, and connector disposed between said first means and said second rod means. The connector The connector is slidably engaged with one end of the rod means, and contains an intermediate wall adapted to limit movement of the rod means and to receive and engage a portion of the rod means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention will be described by reference to the following drawings, in which like numerals refer to like elements, and in which:
[0010] [0010]FIG. 1 is an end view of one preferred rod of the display device of this invention;
[0011] [0011]FIG. 2 is a front view of the rod of FIG. 1;
[0012] [0012]FIG. 3 is a sectional view of the rod of FIG. 1, taken along lines 3 - 3 ;
[0013] [0013]FIG. 4 is a sectional view of the rod of FIG. 1, taken along lines 4 - 4 ;
[0014] [0014]FIG. 5 is a schematic representation of means for connecting the rod of FIGS. 1 - 4 to another, similar rod;
[0015] [0015]FIG. 6 is an end view of the connector used in the display device of the invention;
[0016] [0016]FIG. 7 is a front view of the connector of FIG. 6;
[0017] [0017]FIG. 8 is a side view of the connector of FIGS. 6 - 7 connecting two rods;
[0018] [0018]FIG. 9 is a sectional view of the device depicted in FIG. 8, taken along lines 9 - 9
[0019] [0019]FIG. 10 is a schematic representation of the display device of this invention; and
[0020] [0020]FIG. 11 is another schematic representation of the display device of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] [0021]FIG. 1 is a end view of a preferred rod assembly 10 . Referring to FIG. 1, and in the preferred embodiment depicted therein, rod assembly 10 is preferably an integral assembly comprised of a top rail 12 .
[0022] In the embodiment depicted, rail 12 has a substantially arcuate shape. The connector described elsewhere in this specification is preferably adapted to receive such rail within an interior wall disposed within such connector.
[0023] In one preferred embodiment, depicted in FIG. 1, rail 12 is comprised of an orifice 14 which preferably extends the entire length of rail 12 . This orifice 14 may be of any size which does not substantially adversely affect the mechanical properties of rail 12 . In one aspect of this embodiment, the orifice 14 has a maximum dimension which is from about 5 to about 80 percent of the maximum dimension of the rail 12 .
[0024] In one embodiment, the orifice 14 is filled with a reinforcing material, such as a wire, metal, polyurethane, string, etc.
[0025] Referring again to FIG. 1, and in the preferred embodiment depicted therein, it will be seen that the rod assembly 10 is comprised of a first horizontally extending wing 16 and a second horizontally extending wing 18 . In the embodiment depicted, the wings 16 and 18 are substantially perpendicular to the vertical axis 20 of the rod. In another embodiment, not shown, such wings 16 and 18 may form acute and/or obtuse angles with such vertical axis 20 .
[0026] Referring again to FIG. 1, and in the preferred embodiment depicted therein, each of the wings 16 and 18 is shown as having a substantially rectilinear shape. In another embodiment, not shown, the wings 16 and 18 may have other shapes, such as, e.g., arcuate shapes.
[0027] In the embodiment depicted in FIG. 1, a second orifice 22 is shown disposed between wing 16 and wing 18 , preferably centrally disposed therebetween. The second orifice 22 may be the same size and/or shape as the first orifice 14 , or it may be different. The device 10 may include only orifice 14 , only orifice 22 , both orifices 14 and 22 , and/or one or more additional orifices 14 and/or 22 may extend the entire length of device 10 , or it may extend only along one or more portions of such length. In one embodiment, not shown, the rod assembly 12 contains no orifices.
[0028] Referring again to FIG. 1, the rod 10 is comprised of an exterior wall 24 which has length 26 of at least about 0.2 inches and, more preferably, at least about 0.3 inches.
[0029] [0029]FIG. 2 is a front view of the rod assembly 10 from which details regarding orifices 14 and 18 have been omitted for the sake of simplicity of representation. Referring to FIG. 2, it will be seen that exterior wall 24 is comprised of a multiplicity of resilient slotted orifices 28 .
[0030] For every foot of length of exterior wall 24 , there should be at least about 6 such resilient slotted orifices 28 . It is preferred not to use more than about 36 such slotted orifices 28 per linear foot of exterior wall 24 .
[0031] The resilient slotted orifices 28 operate similarly to the lamp retaining means disclosed in U.S. Pat. No. 5,700,083, the entire disclosure of which is hereby incorporated by reference into this specification.
[0032] The resilient slotted orifices 28 are adapted to receive and removably engage the rail 12 (see, e.g., FIG. 5). Thus, e.g., the resilient slotted orifices 28 also must be substantially arcuate to conform to the arcuate surfaces of rail 12 . The resilent slotted orifices 28 act as clip means.
[0033] Each of the resilient slotted orifices 28 is defined by an arcuate opening 30 communicating with a smaller entry section 32 . The entry section 32 has a smaller width 34 than the maximum width 36 of the arcuate opening 30 . Thus, as will be apparent, the walls 38 and 40 of entry section 32 must be moved in the directions of arrow 40 and 42 to allow rail 12 to enter arcuate opening 30 and be engaged therein by a friction fit.
[0034] As will be apparent, the clip means defined by resilient slotted orifices 28 are adapted to receive and removably engage both electrical lights and rail 12 .
[0035] [0035]FIG. 3 is a sectional view of the rod 10 , taken along lines 3 - 3 . FIG. 4 is a sectional view of the rod 10 , taken along lines 4 - 4 .
[0036] [0036]FIG. 5 is a side view of a first rod 10 removably connected to second rod 10 which is substantially perpendicular to the first rod 10 , extending upwardly out of the plane of the paper as well as downwardly into the plane of the paper.
[0037] As will be apparent to those skilled in the art, the slotted orifices 28 allow the connection of two rods 10 in different planes, substantially orthogonal to each other. However, these slotted orifices 28 do not allow the connection of two rods 10 in the same plane. That, however, is the function of connector 44 .
[0038] [0038]FIG. 6 is an end view of one preferred embodiment of a connector 44 . Referring to FIG. 6, it will be seen that connector 44 is comprised of a body 46 and, disposed therein, orifices 28 , 48 , and 50 .
[0039] The orifice 28 in connector 44 is substantially identical to the orifice 29 in wall 24 (see FIG. 2). The latter orifice 29 , like the former orifice 28 , is comprised of an arcuate section 30 and an entry section 33 .
[0040] The entry section 33 of connector 44 may be identical to the entry section 32 of the wall 24 of rod 10 (see FIG. 2). In the embodiment depicted in FIG. 2, the entry section 32 has substantially linear walls. In the embodiment depicted in FIG. 6, the entry section 33 has substantially arcuate walls. Other configurations for the entry section(s) will be apparent to those skilled in the art.
[0041] The entry section 33 of connector 44 , and its associated arcuate section 29 orifice 48 , and individually and collectively adapted to slidably engage rod 10 Thus, e.g., the orifice 48 is adapted to receive an engage with wings 16 and 18 (see, e.g., FIG. 3).
[0042] [0042]FIG. 7 is a sectional view of connector 44 , taken along its horizontal axis. As will be seen, the connector 44 is comprised of an interior wall 52 .
[0043] The interior wall 52 provides a multiplicity of stop surfaces on both of its sides 54 and 56 . Thus, e.g., section 58 of wall 52 provides a stop surface for rail 12 (see FIG. 3).
[0044] [0044]FIG. 8 illustrates how the connector 44 may be used to connect two rods 10 . The movement of one of the rods 10 is stopped by surface 54 of wall 52 . The movement of the other rod 10 is stopped by surface 56 of wall 52 .
[0045] [0045]FIG. 9 is a sectional view, taken along lines 9 - 9 of FIG. 8, showing one rod 10 removably disposed within connector 440 .
[0046] [0046]FIG. 10 illustrates how a series of the rods 10 may be connected together within a frame 70 . A first rod 72 is connected in to a second rod 74 in the manner depicted in FIG. 5, and the second rod 74 is connected to a third rod 76 in the manner depicted in FIG. 5, and the third rod 76 is connected to a fourth rod 78 in the manner depicted in FIG. 5. As will be apparent, at each connection point, the rods being connected are diposed in planes substantially orthogonal to each other.
[0047] Referring again to FIG. 10, a multiplicity of electric lamps assemblies are removably connected within orifces 28 (see FIG. 2). In another embodiment, the electric lamps are connected by other means to the rods 10 .
[0048] In one embodiment, the electric lamp assemblies 80 are miniature Christmas lights. These miniature Christmas lights are well known. Reference may be had, e.g., to U.S. Pat. Nos. 6,059,423, 5,813,747 (Christmas tree lights), 5,624,181, 5,542,636, 5,485,068, 5,453,664, 5,428,516, 5,410,458, 5,236,374, 5,094,632, 5,682,079, 4,544,318, 4,253,267, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification.
[0049] In one embodiment, the electric lamp assemblies are comprised of an electric cord 82 (see FIG. 10)
[0050] Referring again to FIG. 10, it will be seen that the assembly depicted in comprised of end members 84 , 86 , 88 , and 90 . These end members are provided at opposed terminal ends of the rod 10 , and they fit between the spaced apart surfaces of the frame 70 to effect a snug friction fit of the device within such frame.
[0051] One may use any suitable end members adapted to secure the rods 10 to the inside surfaces of the frame 70 . Thus, by way of illustration, one may use the compressible ends means 28 described in U.S. Pat. No. 5,700,083. These compressible end means 28 are in the shape of cups.
[0052] In the embodiment depicted in FIG. 10, the end means 84 , 86 , 88 , and 90 is preferably an expandable and compressible caps 84 , a sectional view of which is presented in FIG. 10A.
[0053] [0053]FIG. 11 shows a frame 90 within which is disposed an assembly similar to that depicted in FIG. 10 but differing therefrom in that rod assemblies 92 , and 94 are connected by means of connector 44 , and rod means 96 and 98 are also connected by means of a connector 44 . Cross rods 100 , 102 , 104 , and 106 are connected to rods 92 / 94 / 96 / 98 by the use of orifices 28 , as is more clearly depicted in FIG. 5. Christmas light assemblies 80 are connected t the various rods, using orifices 28 , in the manner depicted.
[0054] As will be apparent, by the means of connector 44 , and/or by using orifices 28 , one may make a multiplicity of different shapes and designs in both the X axis, the Y axis, and the Z axis, thereby being able to make many different two dimensional, three dimensional, and four dimensional designs with the rods 10 which can be ornamented with the miniature Christmas tree lights. The rods 10 , or comparable rods 10 , can be made in a variety of shapes, sizes, and configurations to enable “Christmas tree light artists” to design ever more complex and wonderful designs.
[0055] The rod 10 assembly is preferably constructed from a rigid plastic material which has some degree of flexibility. One suitable plastic material which may be used is, e.g., “Compound 51 ”, which is sold by the Vinylex Corporation of Knoxville, Tenn.
[0056] The plastic material used to construct the rod assembly 10 preferably has a tensile strength (as measured by A.S.T.M. D638) of from about 5,000 to about 7,5000 pounds per square inch, a flexural moduls (as measured by A.S.T.M. D790) of from about 280,000 to about 460,000 pounds per square inch a defeledtion temperature at 264 pounds per square inch (as measured by A.S.T.M. D648) of from about 135 to about 180 degrees Fahrenheit, and a specific gravity (as measured by A.S.T.M. D792) of from about 1.25 to about 1.6.
[0057] It is to be understood that the aforementioned description is illustrative only and that changes can be made in the apparatus, in the ingredients and their proportions, and in the sequence of combinations and process steps, as well as in other aspects of the invention discussed herein, without departing from the scope of the invention as defined in the following claims.adapted to be connected to an electric power source to power the electric lamps. See, e.g., U.S. Pat. No. 5,700,083; the entire disclosure of this United States patent is hereby incorporated by reference into this specification.
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An electric light display assembly for displaying electric lights which contains at least two rods and electric lights removably connected to the rods. A connector located between the rods engages each of the rods. Each of the rods contains a top rail section which, optionally, may contain an orifice. A wall located within the connector limits the extent to which the rods can be inserted into the connector.
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BACKGROUND
Controlled steering or directional drilling techniques are commonly used in the oil, water, and gas industry to reach resources that are not located directly below a wellhead. The advantages of directional drilling are well known and include the ability to reach reservoirs where vertical access is difficult or not possible (e.g. where an oilfield is located under a city, a body of water, or a difficult to drill formation) and the ability to group multiple wellheads on a single platform (e.g. for offshore drilling).
Directional drilling devices often utilize a plurality of steering devices arranged in a circle on the exterior surface of a drill string. These steering devices need to be cyclically actuated to achieve steering in desired direction. Conventional control systems for steering devices are unnecessarily complicated and often include a valve for each steering device (e.g., three valves are required to control three steering devices). Accordingly, there is a need for simpler control systems.
SUMMARY OF THE INVENTION
Aspects of the invention provide control systems and methods for directional drilling.
One aspect of the invention provides a system for controlling a first module, a second module, and a third module. The system includes: an inlet configured to receive fluid from a fluid source; a first double-stage valve; and a second double-stage valve. The first double-stage valve is actuatable to a first position wherein fluid from the inlet flows through the first double-stage valve to the second double-stage valve and a second position wherein fluid from the inlet flows through the first double-stage valve to the third module. The second double-stage valve is actuatable to a first position wherein fluid flows from the first double-stage valve to the first module and a second position wherein fluid flows from the first double-stage valve to the second module.
This aspect can have several embodiments. In one embodiment, the first module, the second module, and the third module are bias pads. In another embodiment, the system is received within a drill string. The fluid source can be pressurized drilling fluid within the drill string. In another embodiment, the system can include an exhaust in communication with the first double-stage valve and the second double-stage valve.
The first double-stage valve can include: a first stage in fluid communication with the inlet and in selective communication with the second double-stage valve; a second stage in fluid communication with the inlet and in selective communication with the third module; and a shaft received within the first double-stage valve. The shaft can include: a first valve body received within the first stage and a second valve body received within the second stage.
During actuation of the first double-stage valve to the first position, the shaft can be positioned such that the first valve body is positioned to permit fluid communication between the inlet and the second double-stage valve and the second valve body is positioned to interrupt fluid communication between the inlet and the third module.
During actuation of the first double-stage valve to the second position, the shaft can be positioned such that: the first valve body is positioned to interrupt fluid communication between the inlet and the second double-stage valve; and the second valve body is positioned to permit fluid communication between the inlet and the third module.
The second double-stage valve can include: a first stage having a first chamber in fluid communication with the first double-stage valve and in selective communication with the first module; a second stage having a first chamber in fluid communication with the first double-stage valve and in selective communication with the second module; and a shaft received within the second double-stage valve. The shaft can include a first valve body received within the first stage and a second valve body received within the second stage.
During actuation of the second double-stage valve to the first position, the shaft can be positioned such that the first valve body is positioned to permit fluid communication between the first double-stage valve and the first module and the second valve body is positioned to interrupt fluid communication between the first double-stage valve and the second module.
During actuation of the second double-stage valve to the first position, the shaft can be positioned such that: the first valve body is positioned to interrupt fluid communication between the first double-stage valve and the first module and the second valve body is positioned to permit fluid communication between the first double-stage valve and the second module.
In another embodiment, the first stage of the second double-stage valve further includes a second chamber in fluid communication with the inlet and in selective fluid communication with the first chamber of the first stage of the second double-stage valve; the second stage of the second double-stage valve further includes a second chamber in fluid communication with the inlet and in selective fluid communication with the first chamber of the second stage of the second double-stage valve; and the shaft further includes a third valve body received within the first chamber of the first stage of the second double-stage valve, a fourth valve body received within the second chamber of the first stage of the second double-stage valve, a fifth valve body received within the second chamber of the second stage of the second double-stage valve, and a sixth valve body received within the first chamber of the second stage of the second double-stage valve.
During actuation of the second double-stage valve to the first position, the shaft can be positioned such that the third valve body is positioned to interrupt fluid communication between the second chamber of the first stage and the first chamber of the first stage and the fifth valve body is positioned to interrupt fluid communication between the second chamber of the second stage and the first chamber of the second stage.
During actuation of the second double-stage valve to the second position, the shaft is positioned such that the fourth valve body is positioned to interrupt fluid communication between the second chamber of the first stage and the first chamber of the first stage and the sixth valve body is positioned to interrupt fluid communication between the second chamber of the second stage and the first chamber of the second stage.
In another embodiment, the first double-stage valve can include: a first stage having a first chamber in fluid communication with the inlet, a second chamber in fluid communication with the second double-stage valve and in selective fluid communication with the first chamber, and a third chamber coupled in fluid communication with the exhaust and in selective fluid communication with the second chamber; a second stage having a first chamber in fluid communication with the inlet, a second chamber in fluid communication with the third module and in selective fluid communication with the first chamber, and a third chamber coupled in fluid communication with the exhaust and in selective fluid communication with the second chamber; and a shaft received within the first double-stage valve. The shaft can include: a first valve body received within the third chamber of the first stage; a second valve body received within the first chamber of the first stage; a third valve body received within the first chamber of the second stage; and a fourth valve body received within the third chamber of the second stage.
During actuation of the first double-stage valve to the first position the shaft can be positioned such that: the first valve body is positioned to interrupt fluid communication between the third chamber of the first stage and the second chamber of the first stage; the second valve body is positioned to permit fluid communication between the first chamber of the first stage and the second chamber of the first stage; the third valve body is positioned to interrupt fluid communication between the first chamber of the second stage and the second chamber of the second stage; and the fourth valve body is positioned to permit fluid communication between the third chamber of the second stage and the third chamber of the second stage.
During actuation of the first double-stage valve to the second position the shaft is positioned such that: the first valve body is positioned to permit fluid communication between the third chamber of the first stage and the second chamber of the first stage; the second valve body is positioned to interrupt fluid communication between the first chamber of the first stage and the second chamber of the first stage; the third valve body is positioned to permit fluid communication between the first chamber of the second stage and the second chamber of the second stage; and the fourth valve body is positioned to interrupt fluid communication between the third chamber of the second stage and the third chamber of the second stage.
In another embodiment, the second double-stage valve includes: a first stage having a first chamber in fluid communication with the first double-stage valve, a second chamber in communication with the first module and in selective fluid communication with the first chamber, and a third chamber in fluid communication the exhaust and in selective fluid communication with the second chamber; a second stage having a first chamber in fluid communication with the first double-stage valve, a second chamber in communication with the second module and in selective fluid communication with the first chamber, and a third chamber in fluid communication the exhaust and in selective fluid communication with the second chamber; and a shaft received within the first double-stage valve. The shaft can include: a first valve body received within the third chamber of the first stage; a second valve body received within the first chamber of the first stage; a third valve body received within the first chamber of the second stage; and a fourth valve body received within the third chamber of the second stage.
During actuation of the second double-stage valve to the first position, the shaft can be positioned such that: the first valve body is positioned to interrupt fluid communication between the second chamber of the first stage and the third chamber of the first stage; the second valve body is positioned to permit fluid communication between the first chamber of the first stage and the second chamber of the first stage; the third valve body is positioned to interrupt fluid communication between the first chamber of the second stage and the second chamber of the second stage; and the fourth valve body is positioned to permit fluid communication between the second chamber of the second stage and the third chamber of the second stage.
During actuation of the second double-stage valve to the second position, the shaft can be positioned such that: the first valve body is positioned to permit fluid communication between the second chamber of the first stage and the third chamber of the first stage; the second valve body is positioned to interrupt fluid communication between the first chamber of the first stage and the second chamber of the first stage; the third valve body is positioned to permit fluid communication between the first chamber of the second stage and the second chamber of the second stage; and the fourth valve body is positioned to interrupt fluid communication between the second chamber of the second stage and the third chamber of the second stage.
In another embodiment, the first stage of the second double-stage valve further includes a fourth chamber in communication with the inlet and in selective communication with the first chamber of the first stage of the second double-stage valve; the second stage of the second double-stage valve further includes a fourth chamber in communication with the inlet and in selective communication with the first chamber of the second stage of the second double-stage valve; and the shaft further includes a fifth valve body received within the first chamber of the first stage of the second double-stage valve, a sixth valve body received within the first chamber of the fourth stage of the second double-stage valve, a seventh valve body received within the fourth chamber of the second stage of the second double-stage valve, and an eighth valve body received within the first chamber of the second stage of the second double-stage valve.
During actuation of the second double-stage valve to the first position, the shaft can be positioned such that the fifth valve body is positioned to interrupt fluid communication between the fourth chamber of the first stage and the first chamber of the first stage and the seventh valve body is positioned to interrupt fluid communication between the fourth chamber of the second stage and the first chamber of the second stage.
During actuation of the second double-stage valve to the second position, the shaft can be positioned such that the sixth valve body is positioned to interrupt fluid communication between the fourth chamber of the first stage and the first chamber of the first stage and the eighth valve body is positioned to interrupt fluid communication between the fourth chamber of the second stage and the first chamber of the second stage.
Another aspect of the invention provides a system for controlling a first module, a second module, a third module, and a fourth module. The system includes: an inlet coupled to a fluid source; a first double-stage valve; a second double-stage valve; and a third double-stage valve. The first double-stage valve is actuatable to: a first position wherein fluid from the inlet flows through the first double-stage valve to the second double-stage valves and a second position wherein fluid from the inlet flows through the first double-stage valve to the third double-stage valves. The second double-stage valve is actuatable to a first position wherein fluid from the first double-stage valve flows through the second double-stage valve to the first module and a second position wherein fluid from the first double-stage valve flows through the second double-stage valve to the second module. The third double-stage valve is actuatable to a first position wherein fluid from the first double-stage valve flows through the third double-stage valve to the third module and a second position wherein fluid from the first double-stage valve flows through the third double-stage valve to the fourth module.
Another aspect of the invention provides a method for drilling a curved hole within a wellbore. The method includes: providing a drill string including a first steering module, a second steering module, a third steering module, an inlet configured to receive fluid from a fluid source, a first double-stage valve, and a second double-stage valve; rotating the drill string and actuating the first and second double-stage valves to permit fluid flow to the first module, second module, and third module to steer the drill string, thereby drilling a curved hole within a wellbore. The first double-stage valve can be actuatable to a first position wherein fluid from the inlet flows through the first double-stage valve to the second double-stage valve and a second position wherein fluid from the inlet flows through the first double-stage valve to the third module. The second double-stage valve can be actuatable to a first position wherein fluid flows from the first double-stage valve to the first module and a second position wherein fluid flows from the first double-stage valve to the second module.
In one embodiment, fluid flows to the first module, second module, and third module in a cyclic pattern.
DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference characters denote corresponding parts throughout the several views and wherein:
FIG. 1 illustrates a wellsite system in which the present invention can be employed;
FIGS. 2A-2C illustrates the structure and operation of a control system for selectively permitting flow from an inlet to a first module, a second module, and a third module according to one embodiment of the invention;
FIG. 3 illustrates an embodiment of the invention without fourth chambers;
FIG. 4 illustrates an embodiment of the invention that does not process exhaust from the modules;
FIGS. 5A-5D depict the structure and operation of a control system for selectively permitting flow from an inlet to a first module, a second module, a third module, and a fourth module according to one embodiment of the invention; and
FIG. 6 depicts a method of directional drilling according to one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Aspects of the invention provide control systems and methods for directional drilling. Various embodiments of the invention can be used in wellsite systems.
Wellsite System
FIG. 1 illustrates a wellsite system in which the present invention can be employed. The wellsite can be onshore or offshore. In this exemplary system, a borehole 11 is formed in subsurface formations by rotary drilling in a manner that is well known. Embodiments of the invention can also use directional drilling, as will be described hereinafter.
A drill string 12 is suspended within the borehole 11 and has a bottom hole assembly (BHA) 100 which includes a drill bit 105 at its lower end. The surface system includes platform and derrick assembly 10 positioned over the borehole 11 , the assembly 10 including a rotary table 16 , kelly 17 , hook 18 and rotary swivel 19 . The drill string 12 is rotated by the rotary table 16 , energized by means not shown, which engages the kelly 17 at the upper end of the drill string. The drill string 12 is suspended from a hook 18 , attached to a traveling block (also not shown), through the kelly 17 and a rotary swivel 19 which permits rotation of the drill string relative to the hook. As is well known, a top drive system could alternatively be used.
In the example of this embodiment, the surface system further includes drilling fluid or mud 26 stored in a pit 27 formed at the well site. A pump 29 delivers the drilling fluid 26 to the interior of the drill string 12 via a port in the swivel 19 , causing the drilling fluid to flow downwardly through the drill string 12 as indicated by the directional arrow 8 . The drilling fluid exits the drill string 12 via ports in the drill bit 105 , and then circulates upwardly through the annulus region between the outside of the drill string and the wall of the borehole, as indicated by the directional arrows 9 . In this well known manner, the drilling fluid lubricates the drill bit 105 and carries formation cuttings up to the surface as it is returned to the pit 27 for recirculation.
The bottom hole assembly 100 of the illustrated embodiment includes a logging-while-drilling (LWD) module 120 , a measuring-while-drilling (MWD) module 130 , a roto-steerable system and motor, and drill bit 105 .
The LWD module 120 is housed in a special type of drill collar, as is known in the art, and can contain one or a plurality of known types of logging tools. It will also be understood that more than one LWD and/or MWD module can be employed, e.g. as represented at 120 A. (References, throughout, to a module at the position of 120 can alternatively mean a module at the position of 120 A as well.) The LWD module includes capabilities for measuring, processing, and storing information, as well as for communicating with the surface equipment. In the present embodiment, the LWD module includes a pressure measuring device.
The MWD module 130 is also housed in a special type of drill collar, as is known in the art, and can contain one or more devices for measuring characteristics of the drill string and drill bit. The MWD tool further includes an apparatus (not shown) for generating electrical power to the downhole system. This may typically include a mud turbine generator (also known as a “mud motor”) powered by the flow of the drilling fluid, it being understood that other power and/or battery systems may be employed. In the present embodiment, the MWD module includes one or more of the following types of measuring devices: a weight-on-bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, and an inclination measuring device.
A particularly advantageous use of the system hereof is in conjunction with controlled steering or “directional drilling.” In this embodiment, a roto-steerable subsystem 150 ( FIG. 1 ) is provided. Directional drilling is the intentional deviation of the wellbore from the path it would naturally take. In other words, directional drilling is the steering of the drill string so that it travels in a desired direction.
Directional drilling is, for example, advantageous in offshore drilling because it enables many wells to be drilled from a single platform. Directional drilling also enables horizontal drilling through a reservoir. Horizontal drilling enables a longer length of the wellbore to traverse the reservoir, which increases the production rate from the well.
A directional drilling system may also be used in vertical drilling operation as well. Often the drill bit will veer off of a planned drilling trajectory because of the unpredictable nature of the formations being penetrated or the varying forces that the drill bit experiences. When such a deviation occurs, a directional drilling system may be used to put the drill bit back on course.
A known method of directional drilling includes the use of a rotary steerable system (“RSS”). In an RSS, the drill string is rotated from the surface, and downhole devices cause the drill bit to drill in the desired direction. Rotating the drill string greatly reduces the occurrences of the drill string getting hung up or stuck during drilling. Rotary steerable drilling systems for drilling deviated boreholes into the earth may be generally classified as either “point-the-bit” systems or “push-the-bit” systems.
In the point-the-bit system, the axis of rotation of the drill bit is deviated from the local axis of the bottom hole assembly in the general direction of the new hole. The hole is propagated in accordance with the customary three-point geometry defined by upper and lower stabilizer touch points and the drill bit. The angle of deviation of the drill bit axis coupled with a finite distance between the drill bit and lower stabilizer results in the non-collinear condition required for a curve to be generated. There are many ways in which this may be achieved including a fixed bend at a point in the bottom hole assembly close to the lower stabilizer or a flexure of the drill bit drive shaft distributed between the upper and lower stabilizer. In its idealized form, the drill bit is not required to cut sideways because the bit axis is continually rotated in the direction of the curved hole. Examples of point-the-bit type rotary steerable systems, and how they operate are described in U.S. Patent Application Publication Nos. 2002/0011359; 2001/0052428 and U.S. Pat. Nos. 6,394,193; 6,364,034; 6,244,361; 6,158,529; 6,092,610; and 5,113,953.
In the push-the-bit rotary steerable system there is usually no specially identified mechanism to deviate the bit axis from the local bottom hole assembly axis; instead, the requisite non-collinear condition is achieved by causing either or both of the upper or lower stabilizers to apply an eccentric force or displacement in a direction that is preferentially orientated with respect to the direction of hole propagation. Again, there are many ways in which this may be achieved, including non-rotating (with respect to the hole) eccentric stabilizers (displacement based approaches) and eccentric actuators that apply force to the drill bit in the desired steering direction. Again, steering is achieved by creating non co-linearity between the drill bit and at least two other touch points. In its idealized form, the drill bit is required to cut side ways in order to generate a curved hole. Examples of push-the-bit type rotary steerable systems and how they operate are described in U.S. Pat. Nos. 5,265,682; 5,553,678; 5,803,185; 6,089,332; 5,695,015; 5,685,379; 5,706,905; 5,553,679; 5,673,763; 5,520,255; 5,603,385; 5,582,259; 5,778,992; and 5,971,085.
Control Devices for Three-Module Systems
Referring now to FIGS. 2A-2C , a control system 200 according to one embodiment of the invention for selectively permitting flow from an inlet 202 to a first module 204 , a second module 206 , and a third module 208 is depicted. Control system 200 includes a first double-stage valve 210 and a second double-stage valve 212 . The first double-stage valve 210 includes a first stage 214 and a second stage 216 . The second double-stage valve 212 includes a first stage 218 and a second stage 220 .
The first stage 214 of the first double-stage valve 210 can include a first chamber 222 , a second chamber 224 in selective fluid communication with the first chamber 222 , and a third chamber 226 in selective fluid communication with the second chamber 224 . The second stage 216 of the first double-stage valve 210 includes a first chamber 228 , a second chamber 230 in selective fluid communication with the first chamber 228 , and a third chamber 232 in selective fluid communication with the second chamber 230 .
The first double-stage valve 210 can include shaft 234 received within both stages 214 , 216 . The shaft 234 can include a first valve body 236 received within the third chamber 226 of the first stage 214 , a second valve body 238 received within the first chamber 222 of the first stage 214 , a third valve body 240 received within the first chamber 228 of the second stage 216 , and a fourth valve body 242 received within the third chamber 232 of the second stage 216 .
The first stage 218 of the second double-stage valve 212 can include a first chamber 244 , a second chamber 246 in selective fluid communication with the first chamber 244 , a third chamber 248 in selective fluid communication with the second chamber 246 , and a fourth chamber 250 in selective fluid communication with the first chamber 244 . The second stage 220 of the second double-stage valve 212 can include a first chamber 252 , a second chamber 254 in selective fluid communication with the first chamber 252 , a third chamber 256 in selective fluid communication with the second chamber 254 , and a fourth chamber 258 in selective fluid communication with the first chamber 252 .
The second double-stage valve 212 can include shaft 260 received within both stages 218 , 220 . The shaft 260 can include a first valve body 262 received within the third chamber 248 of the first stage 218 , a second valve body 264 received within the first chamber 244 of the first stage 218 , a third valve body 266 received within the first chamber 252 of the second stage 220 , a fourth valve body 268 received within the third chamber 256 of the second stage 220 , a fifth valve body 270 received within the first chamber 244 of the first stage 218 , a sixth valve body 272 received within the fourth chamber 250 of the first stage 218 , a seventh valve body 274 received within the fourth chamber 258 of the second stage 220 , and an eighth valve body 276 received within the first chamber 252 of the second stage 220 .
Fourth chambers 250 , 258 ensure that high pressure is maintained in first chambers 246 , 252 when the first valve 210 is actuated to the second position, thereby ensuring fast actuation of first module 204 and second module 206 . Additionally or alternatively, fourth chambers 250 , 258 could hold pressure-balance elements to seal the actuating device (not depicted) of valve 212 from the working fluid (e.g., mud) received from inlet 202 . In such an embodiment, the actuator could be filled with oil at a pressure substantially equal to the pressure within fourth chambers 250 , 258 , thereby minimizing stress on sealing elements (e.g., bellows, rubber boots, and the like) between the actuator and the fourth chambers 250 , 258 .
In FIG. 2A , both the first double-stage valve 210 and the second double-stage valve 212 are in first positions. Fluid flows from inlet 202 through the first chamber 222 and second chamber 224 of the first stage 214 of the first double-stage valve 210 to the first chamber 244 and the second chamber 246 of the first stage 218 of the second double-stage valve 212 to the first module 204 . Third module 208 is concurrently vented to exhaust 278 .
In FIG. 2B , both the first double-stage valve 210 is in the first position and the second double-stage valve 212 is the second position. Fluid flows from inlet 202 through the first chamber 222 and second chamber 224 of the first stage 214 of the first double-stage valve 210 to the first chamber 252 and the second chamber 254 of the second stage 220 of the second double-stage valve 212 to the second module 206 . First module 204 and third module 208 are concurrently vented to exhaust 278 .
In FIG. 2C , both the first double-stage valve 210 is in the second position and the second double-stage valve 212 is in the first position. Fluid flows from inlet 202 through the first chamber 228 and second chamber 230 of the second stage 216 of the first double-stage valve 210 to the third module 208 . First module 204 and second module 206 are concurrently vented to exhaust 278 .
Valves 210 , 212 can be actuated by a variety of devices. For example, a pinion can interface with a plurality of rack gear teeth on shafts 234 , 260 . Alternatively, shafts 234 , 260 can extend beyond the wall of valves 210 , 212 and interface with an external actuator. A variety of valve actuators are described in publications such as T. Christopher Dickenson, Valves, Piping & Pipelines Handbook 138-45 (3d ed. 1999); and Peter Smith, Valve Selection Handbook (5th ed. 2004).
The actuation of valves 210 , 212 can be effected by a control device (not depicted) to maintain the proper angular position of the bottom hole assembly relative to the subsurface formation. In some embodiments, the control device is mounted on a bearing that allows the control device to rotate freely about the axis of the bottom hole assembly. The control device, according to some embodiments, contains sensory equipment such as a direction and inclination (D&I) sensor, rotational speed sensor, accelerometers (e.g., three-axis accelerometers), and/or magnetometer sensors to detect the inclination and azimuth of the bottom hole assembly. The control device can further communicate with sensors disposed within elements of the bottom hole assembly such that said sensors can provide formation characteristics or drilling dynamics data to control unit. Formation characteristics can include information about adjacent geologic formation gather from ultrasound or nuclear imaging devices such as those discussed in U.S. Patent Publication No. 2007/0154341, the contents of which is hereby incorporated by reference herein. Drilling dynamics data may include measurements of the vibration, acceleration, velocity, and temperature of the bottom hole assembly.
In some embodiments, control device is programmed above ground to following a desired inclination and direction. The progress of the bottom hole assembly can be measured using MWD systems and transmitted above-ground via a sequences of pulses in the drilling fluid, via an acoustic or wireless transmission method, or via a wired connection. If the desired path is changed, new instructions can be transmitted as required. Mud communication systems are described in U.S. Patent Publication No. 2006/0131030, herein incorporated by reference. Suitable systems are available under the POWERPULSE™ trademark from Schlumberger Technology Corporation of Sugar Land, Tex.
Referring to FIG. 3 , each stage 218 , 220 of second double-stage valve 212 be fabricated without a fourth chamber 250 , 258 . Such an embodiment can be advantageous due to the simpler valve design and because only a single valve type (i.e., a double-stage, six-chamber valve) is needed in inventory. (The elements in FIG. 3 correspond to like-labeled elements in FIG. 2 and the related description herein.) In such an embodiment, the actuator of the second valve 312 can be coupled with a dynamic oil compensator, which communicates with second chamber 324 of first valve 310 .
Referring to FIG. 4 , an embodiment of the invention 400 that does not process exhaust from modules 404 , 406 , 408 is provided. In such an embodiment, modules 404 , 406 , 408 can include an exhaust port from which exhaust can be vented. As will be appreciated from FIG. 4 , chambers 422 , 428 , 444 , 450 , 458 , and 452 generally correspond to first chambers 222 , 228 , 244 , 250 , 258 , and 252 , respectively, in FIG. 2 . Likewise, chambers 450 and 458 can be omitted as discussed above in the context of FIG. 4 .
Control Devices for Four-Module Systems
Referring now to FIGS. 5A-5D , a control system 500 for selectively permitting flow from an inlet 502 to a first module 504 , a second module 506 , a third module 508 , and a fourth module 510 is depicted. System 500 includes a first valve 512 , a second valve 514 , and a third valve 516 . Valves 512 , 514 , 516 can be the same or similar to the valves described herein.
For example, valve 512 can have chambers 518 and 520 . Shaft 522 can be received within valve 512 and can include valve body 524 received within chamber 518 and valve body 526 received within chamber 520 .
Valve 514 can include chambers 528 , 530 , 532 , and 534 . Shaft 536 can be received within valve 514 and can include discs 538 and 540 received within chamber 528 , valve body 542 received within chamber 530 , valve body 544 received within chamber 532 , and discs 546 and 548 received within chamber 534 .
Valve 516 can include chambers 550 , 552 , 554 , and 556 . Shaft 558 can be received within valve 516 and can include discs 560 and 562 received within chamber 550 , valve body 564 received within chamber 552 , valve body 560 received within chamber 554 , and discs 562 and 564 received within chamber 556 .
In FIG. 5A , valves 512 and 514 are both actuated to the first positions to permit flow to the first module 504 . In FIG. 5B , valve 512 is actuated to the first position and valve 514 is actuated to the second position to permit fluid flow to the second module 506 . In FIG. 5C , valve 512 is actuated to the second position and valve 516 is actuated to the first position to permit fluid flow to the third module 508 . In FIG. 5D , valve 512 is actuated to the second position and valve 516 is actuated to the second position to permit fluid flow to the fourth module 510 .
As will be appreciated by one of skill in the art, the principles of the invention can be applied to control systems having any number of modules. For example, system 500 could be modified to control five modules by placing additional valve in place of any of the modules 504 , 506 , 508 , 510 and coupling two modules to the additional valve.
Thus, to control n modules (n being an integer greater than 1), a system can be fabricated having n−1 valves.
Integration within Drill Strings
The systems described herein can be installed within drill strings, bottom hole assemblies, and the like. In such an embodiment, the inlet 202 can be in fluid communication with the interior of the drill string. The systems can be used to control any hydraulic or pneumatic devices such as bias pads, motors, and the like.
Methods of Directional Drilling
Referring now to FIG. 6 , a method of directional drilling 600 is provided. In step S 602 , a drill string is provided including a n steering modules, and n−1 valves. Exemplary arrangements of valves and steering modules are described herein. In step S 604 , the drill string is rotated. In step S 606 , the valves are actuated to control fluid flow to the steering modules.
INCORPORATION BY REFERENCE
All patents, published patent applications, and other references disclosed herein are hereby expressly incorporated by reference in their entireties by reference.
EQUIVALENTS
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents of the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
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A system for controlling a first module, a second module, and a third module. The system includes: an inlet configured to receive fluid from a fluid source; a first double-stage valve; and a second double-stage valve. The first double-stage valve is actuatable to a first position wherein fluid from the inlet flows through the first double-stage valve to the second double-stage valve and a second position wherein fluid from the inlet flows through the first double-stage valve to the third module. The second double-stage valve is actuatable to a first position wherein fluid flows from the first double-stage valve to the first module and a second position wherein fluid flows from the first double-stage valve to the second module.
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FIELD OF THE INVENTION
[0001] This invention relates to a package of disposable gloves and to a method and an apparatus which can use the package to enable the gloves to be applied to a user's hands.
BACKGROUND OF THE INVENTION
[0002] The use of disposable gloves is becoming common in a number of industries such as food handling establishments where food such as sandwiches or the like may be made and sold to a customer, or other open food products such as meats and the like are selected from a tray and wrapped for a customer to purchase. The use of such gloves is intended to improve hygiene and prevent the spread of germs which may take place if such food products are handled by the bare hands.
[0003] Conventionally, when such gloves are used they are merely selected from a box and are applied by the user to the user's hands. This requires the user to have significant contact with the gloves prior to, and during, application of the gloves to the user's hands which means that the outer surface of the gloves can become contaminated with any other germs or other unwanted material already on the user's hands.
SUMMARY OF THE INVENTION
[0004] The object of the present invention is to provide a package of disposable gloves which may be used with a method and an apparatus to more hygienically apply the gloves to a user's hands, and to such a method and an apparatus.
[0005] The invention in a first aspect may be said to reside in a package of disposable gloves, comprising:
a plurality of gloves connected to one another in a line by a frangible connection which is breakable to separate one glove from the line; a glove edge transverse to the frangible connection to form an open cuff of each glove; and wherein each glove is formed from two layers which are joined together by a join to define the glove.
[0009] Preferably the gloves are formed in glove panels with each panel being connected to an adjacent panel by the frangible connection, the join comprising a heat seal in each panel defining the shape of the glove.
[0010] In one embodiment each panel is a rectangular panel and has webs outwardly of the join.
[0011] In one embodiment the glove has defined fingers and cuts are formed through the webs between the fingers to separate the fingers.
[0012] However, in other embodiments the webs between the fingers may be left intact.
[0013] In another embodiment the glove has fingers and the join of the glove which defines the fingers forms the periphery of the panel at the fingers.
[0014] Thus, in this embodiment no web is formed between the fingers of each glove.
[0015] In other embodiments the glove may be a mitten without defined fingers.
[0016] Preferably the package of disposable gloves is in the form of a roll of gloves.
[0017] This aspect of the invention may also be said to reside in a package of disposable gloves for use with a glove applying machine for enabling the gloves to be applied to a user's hands, comprising:
a plurality of gloves connected to one another in a line by a frangible connection which is breakable to separate one glove from the line; each glove being formed from two layers which are joined together by a join to define the glove; and locating indicia for allowing the gloves to be registered in the apparatus.
[0021] In one embodiment the locating indicia comprises a marking.
[0022] In another embodiment the locating indicia comprises a hole.
[0023] In one embodiment of the invention at least one pin for location in the hole to register the package of gloves in the apparatus when a new package of gloves is loaded into the apparatus, to enable the gloves to be indexed through the apparatus.
[0024] Preferably the gloves are formed in glove panels with each panel being joined to an adjacent panel by the frangible connection, the join comprising a heat seal in each panel defining the shape of the glove.
[0025] Preferably each panel has a web portion outwardly of the join and the locating indicia is located on the web portion.
[0026] According to one embodiment, preferably an open cuff of each glove is formed at the edge of each panel that is transverse to the frangible connection. In other words, the glove is oriented horizontally or “East to West” relative to the line.
[0027] According to an alternative embodiment, preferably an open cuff of each glove is formed at an edge of the panel at the frangible connection between the panels. In other words, the glove is oriented vertically or “North to South” relative to the line.
[0028] In the most preferred embodiment the marking indicia comprises two holes in each panel.
[0029] Preferably the frangible connection comprises a perforated line.
[0030] However, in other embodiments the frangible connection could comprise small attaching strips between each glove, the attaching strips being breakable when one glove is pulled away from an adjacent glove in the line of gloves.
[0031] Preferably the package of disposable gloves comprises a roll of gloves.
[0032] The invention in a second aspect may be said to reside in a method of hygienically locating a glove on a user's hand, comprising:
mechanically locating the glove at a hand insertion location; opening the glove; and inserting a hand in the glove.
[0036] Preferably the glove is opened at the hand insertion location.
[0037] Preferably the glove is supplied as one glove in a line of gloves joined by a frangible connection, so that the glove when the user's hand is located in the glove is torn from the line by movement of the user's hand and the glove.
[0038] Preferably the glove has an open cuff and a finger portion and the glove is located in an orientation such that a line between the cuff of the glove and the end of the finger portion of the glove is substantially horizontal.
[0039] Preferably the glove has a first layer defining the back of the glove and a second layer defining the palm of the glove, and the glove is open by moving the first and second layers apart to enable a person to insert his/her hand through the cuff into the glove.
[0040] Most preferably both the first and second layers are moved. However, in other embodiments only one of the layers could be moved whilst the other is substantially stationery.
[0041] The invention may also be said to reside in an apparatus for enabling hygienic location of a glove on a hand, comprising:
a storage for storing a package of disposable gloves; an indexing device for moving the gloves from the storage to a hand insertion station; and a glove opening device for opening a glove so a user can insert his or her hand into the glove at the hand insertion station.
[0045] In one embodiment of the invention the storage is a compartment for storing a roll of gloves comprising a continuous line of gloves with the gloves being joined to one another by a frangible connection in the line.
[0046] Preferably, the indexing device comprises a movable gripping device for movement between the hand insertion station and a line gripping station so that the device can move relative to the line between the insertion station and the gripping station, and can grip the line at the gripping station so the line is drawn with the device upon return movement from the gripping station to the hand insertion station.
[0047] Preferably the gloves in the line have a first layer and a second layer and the glove opening device comprises a gripper for gripping at least one of the layers, and a gripper moving element for moving the gripper and the at least one of the layers relative to the other layer to open the glove.
[0048] Preferably the glove is gripped and opened during movement of the gripper device between the gripping station and the hand insertion station.
[0049] According to one embodiment, the gripper comprises a block of material through which air can flow, and the gripper mover element comprises a bladder, wherein upon inflation of the bladder the material is forced against at least one of the layers, and when vacuum is applied to the material air flows through the material to hold the layer against the material, and upon deflation of the bladder the material and the layer are drawn away from the other layer to thereby open the glove.
[0050] Preferably the material comprises a open cell foam material.
[0051] Preferably the bladder has a spring element for controlling inflation and deflation of the bladder to firstly move the material against the layer upon inflation of the bladder, and draw the material and the layer away from the other layer upon deflation of the bladder.
[0052] According to an alternative embodiment, the gripper comprises an inflatable assembly and a sealing formation having one or more than one suction points, wherein upon inflation of the inflatable assembly, at least one of the suctions points of the sealing formation is located against at least one of the layers, and upon deflation of the inflatable assembly, the layer is drawn away from the other layer to thereby open the glove.
[0053] Preferably, the inflatable assembly comprises a bellows.
[0054] Preferably, the rate of inflation or deflation of the inflatable assembly is controlled by a piston and cylinder that supplies air into, or draws air from, the inflatable assembly, and suction of the suctions points is controlled by a separate piston and cylinder.
[0055] Preferably, the or each piston and cylinder assembly is operable by a linear actuator controlled by a solenoid.
[0056] Preferably the indexing device further comprises a pair of rollers, a gear attached to each roller the gears meshing together so the rollers are able to rotate in unison but in opposite directions, the rollers having a groove and rib so that when the groove of one roller engages with the rib of the other roller the line is gripped between the rollers, and so that upon movement of the indexing device from the gripping station to the hand insertion station the line is drawn off the package, and upon movement of the indexing device from the hand insertion station to the gripping station the rollers rotate relative to the line during movement of the indexing device until the groove and rib re-engage to thereby grip the line between the rollers.
[0057] In one embodiment a driver is provided to rotate the rollers only during movement of the gripping device from the hand insertion station to the gripping station.
[0058] In one embodiment the driver comprises a motor may be provided for facilitating rotation of the rollers during movement of the indexing device from the hand insertion station to the gripping station.
[0059] The motor may have a clutch to prevent rotation of the rollers during movement of the indexing device from the gripping station to the hand insertion station.
[0060] In another embodiment the driver comprises a rack and gear assembly, with the gear coupled to one of the rollers and the rack fixed and engaging the gear so that when the indexing device is moved from the hand insertion station to the gripping station engagement of the gear and the rack causes rotation of the gear and therefore rotation of the rollers.
[0061] In this embodiment the gear also synchronises rotation of the rollers with movement of the indexing device between the hand insertion station and the gripping station.
[0062] Preferably a sensor is provided for sensing the insertion of a user's hand into the glove at the hand insertion station, and then removal of the glove from the line at the hand insertion station, to thereby activate the indexing device to cause the indexing device to move from the hand insertion station, to the gripping station, and back to the hand insertion station so a new glove is open at the hand insertion station ready for insertion of a user's hand.
[0063] Preferably the apparatus includes locating elements for engaging the line when a new package is located in the apparatus to correctly register the line in the apparatus.
[0064] Preferably the line has holes and the locating elements comprise pins for passing through the holes when the package is loaded into the apparatus, and for withdrawal from the holes after the package is loaded in the apparatus.
[0065] Preferably the pins are driven between a locating position where they can pass through the holes and a retracted position away from the line, by opening and closing movement of a door of the apparatus to provide access to the storage of the apparatus.
[0066] Preferably at least one of the rollers is spring biased into engagement with the other of the rollers so that the rollers can be slightly separated to facilitate location of the line between the rollers during loading of a package into the apparatus.
[0067] This aspect of the invention may also be said to reside in an apparatus for enabling hygienic location of a glove on a hand, comprising:
a housing having a front opening and a bottom opening which provide access to a hand insertion station; a storage for storing a package of disposable gloves, so the gloves are presented at the hand insertion station in an orientation so that a line between a cuff portion of the gloves and a fingertip portion of the gloves is substantially horizontal, and with the cuff portion of the gloves facing the front opening; a glove indexing device for moving a glove from the storage to the hand insertion station so a user can insert his or her hand into the glove through the cuff portion; and wherein to locate the glove on the hand and remove the glove from the apparatus, a user inserts his or hand through the front opening into the glove and then moves his or her hand with the glove on his or her hand downwardly through the bottom opening.
[0072] This aspect of the invention may also be said to reside in an apparatus for enabling hygienic location of the glove on a hand, comprising:
a storage for storing a package of disposable gloves; an indexing device for moving the gloves from the storage to a hand insertion station; and a glove opening device comprising at least one block of material through which air can flow, an inflatable bladder, and at least one air supply and vacuum system for supplying air to the bladder to inflate the bladder to move the block to a position adjacent the glove, for drawing a vacuum through the block so a portion of the glove is drawn against the block, and for deflating the bladder so the block moves with the bladder to move a portion of the glove away from another portion of the glove to open the glove to enable a user to insert his or hand into the glove at the hand insertion station.
BRIEF DESCRIPTION OF THE DRAWINGS
[0076] Preferred embodiments of the invention will be described, by way of example, with reference to the accompanying drawings in which:
[0077] FIG. 1 is a view of a line of gloves formed as a package according to one embodiment;
[0078] FIG. 2 is a view similar to FIG. 1 of a second embodiment;
[0079] FIG. 3 is a view along the line of FIG. 1 ;
[0080] FIG. 4 is a side view of the package of gloves in the form of a roll of gloves;
[0081] FIG. 5 is a more detailed view of one glove in the line of FIG. 1 ;
[0082] FIG. 6 is a more detailed view of one glove of the type shown in FIG. 1 in a modified form;
[0083] FIG. 7 is a side view of a machine for forming the package of gloves;
[0084] FIG. 8 is a top view of the machine of FIG. 7 ;
[0085] FIG. 9 is a side view of an apparatus according to one embodiment of the invention;
[0086] FIG. 10 is a front view of the apparatus of FIG. 9 ;
[0087] FIG. 11 is a perspective view of the apparatus of FIG. 9 ;
[0088] FIG. 12 is a detailed view of a roller and gear assembly using the preferred embodiment of the invention;
[0089] FIG. 13 is a schematic view of part of the apparatus of FIG. 9 ;
[0090] FIG. 14 is a perspective view of part of the apparatus shown in FIG. 13 ;
[0091] FIG. 15 is a schematic front view of an apparatus according to FIG. 9 ;
[0092] FIG. 16 is a side view of part of the apparatus of FIG. 15 ;
[0093] FIG. 17 is a schematic view of part of the apparatus of FIG. 9 ;
[0094] FIG. 18 is a schematic view of a part of the apparatus according to another embodiment of the invention;
[0095] FIG. 19 is a cross-sectional view of another part of the apparatus according to an embodiment of the invention;
[0096] FIG. 20 is a perspective view of a section of the part of the apparatus shown in FIG. 18 ; and
[0097] FIG. 21 is a schematic diagram of a control system used in the embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0098] With reference to FIG. 1 a line of gloves 10 is shown which form a package of gloves such as a roll 15 as shown in FIG. 4 . In other embodiments the package could comprise a zigzag layering of the line of gloves or any other compact packaging of the gloves.
[0099] The line of gloves 10 is formed from a first layer 18 and a second layer 20 (see FIG. 3 ). Each glove 11 in the line of gloves 10 is defined by a heat seal join 21 which defines the periphery of the glove (in other words the shape of the glove). Thus, the join heat seals the two layers 18 to 20 together along the outline 11 a of the gloves to thereby define the shape of the gloves.
[0100] In the embodiment of FIG. 1 , the gloves are formed in glove panels 25 formed by the two layers 18 and 20 and the glove panels 25 are defined by a frangible connection 26 . The frangible connection 26 preferably comprises a perforated line so that one glove can be easily torn from the line 10 as will be described in more detail hereinafter.
[0101] In the embodiment of FIG. 1 the glove panels 25 have opposite edges 27 and 29 which are not connected to one another except where the join 21 intersects or contacts the edges 27 and 29 . This therefore defines an open cuff 30 of each glove as is best shown in FIG. 3 . The edge 29 may be beaded so that the open cuff of each glove 11 has a bead 31 to slightly strengthen that part of the glove and make it easy for a person to insert his or her hand into the glove.
[0102] Each panel 25 is also provided with two holes 33 which form locating indicia to facilitate location of the gloves in a glove applying apparatus to be described hereinafter.
[0103] FIG. 2 shows a second embodiment in which the gloves are configured in an “north-south” configuration rather than the “east-west” configuration of FIG. 1 . Like reference numerals indicate like paths to those previously described.
[0104] In this embodiment the open cut of the glove will be formed when the perforated line 26 is torn during the separation of one glove 11 from the line of gloves 10 .
[0105] FIG. 5 is a more detailed view of one glove 11 formed in a panel 26 of the type shown in FIG. 1 .
[0106] As will be apparent from both FIG. 1 and FIG. 5 webs 35 are left outwardly of the join 11 a, formed from the layers 18 and 20 of each panel 25 .
[0107] If desired, cuts 37 can be made in the webs 35 between the fingers 11 b of the gloves to separate the fingers. However, in other embodiments the webs can remain intact because they will be relatively thin and will still allow sufficient degree of relative movement of the fingers form most applications.
[0108] A cut 37 is also provided between the thumb 11 c of the glove 11 and the index finger 11 b adjacent the thumb 11 c.
[0109] Since the disposable glove is usually only used for a very small amount of time, perhaps in the order of only 30 seconds or less, the webs will not interfere with movement of the hand or the work the person wearing the gloves is required to do.
[0110] In still further embodiments of the invention the panels 25 may be of the type shown in FIG. 6 in which the panel is cut about the join 11 a defining the fingers 11 b so that no webs are provided between the fingers 11 b and the thumb 11 c . Webs 35 remain outwardly of the palm portion 11 d of the hand.
[0111] In this embodiment the edge 27 is defined by the shape of the fingers as shown in FIG. 6 .
[0112] In the embodiment of FIG. 6 the perforated line 26 extends from the edge 29 to the tip of the thumb 11 c and between the edge 29 and the tip of the small finger 11 b.
[0113] FIGS. 7 and 8 show, schematically, an example of how the package of gloves is formed.
[0114] Layers 18 and 20 are supplied from supply rolls 40 and 41 of the layer material and guided around one or more sets of idler rollers 42 to a heat sealing station 43 . At the heat sealing station 43 the join 21 defining the periphery of the glove 11 a is formed by applying heat along the line 11 a via appropriate parts of the station 43 to heat weld the layers 18 and 20 together along the line 11 a which defines the shape of the glove. Thus, the layers 18 and 20 are joined at the line 11 a.
[0115] The layers 18 are then indexed to a cutting and perforating station 45 where the perforated line 26 is formed and also the holes 33 and cuts 37 , the formed line of gloves 10 is then rolled onto a roll to form the package of gloves 15 shown in FIG. 4 .
[0116] It should be understood that the apparatus shown in FIGS. 7 and 8 is schematic and merely illustrative and not intended to show all componentry of the machine performing the package of gloves. In any event, it will be appreciated that the compoenentry not shown in detail in FIG. 7 may readily be constituted by a combination of commercially available components.
[0117] FIGS. 9 to 14 , and 16 and 17 show parts of an apparatus according to one embodiment of the invention. FIG. 15 shows a schematic illustration of the assembled apparatus comprising the parts shown in FIGS. 9 to 14 , and 16 and 17 for hygienically applying the glove to a user's hand.
[0118] With reference to FIGS. 9 , 10 and 11 , the apparatus has a glove line 10 indexing device 48 comprising a support frame 50 which supports a pair of glove opening devices 52 . Roll 15 of the gloves 11 is supported on a shaft (not shown) in a storage 49 and the line of gloves 10 is guided from the roll 15 through the devices 52 as is best shown in FIG. 10 and FIG. 11 .
[0119] The frame 50 comprises two U-shaped frame members 51 which are supported on tracks 53 which, in turn, are supported by outer housing 55 (see FIG. 15 ).
[0120] The frame 50 is also connected to a pair of linear bearings 56 for moving the frame 50 vertically on guide tracks 53 as will be explained in more detail hereinafter.
[0121] The frame 50 also supports a line gripper 54 to gripping the line 10 . The line gripper 54 comprises a pair of rollers 58 between which the line 10 of gloves 11 is guided. The rollers 58 have gears 59 at one end and the gears 59 are meshed to synchronise rotation of the rollers 58 so that they rotate in unison with one another but in opposite directions.
[0122] The outer housing 55 also supports two pressure pumps 60 for driving the devices 52 as will also be explained in more detail hereinafter.
[0123] An encoder 61 is provided on shaft 62 on which one of the rollers 58 is mounted for monitoring rotation of the rollers 58 .
[0124] Movement of the frame 50 and the rollers 59 and associated operation of the devices 52 is as follows.
[0125] FIGS. 9 and 10 show the frame 50 in a raised upper gripping position at gripper station G in which the line of gloves 10 is gripped by the rollers 59 and extends between the devices 52 . The linear bearing 56 moves the frame and rollers 59 downwardly to the hand insertion station H shown in FIG. 11 thereby pulling the line of gloves 10 downwardly with the frame 50 off the roll 15 .
[0126] During downward movement of the frame 50 pressure is supplied to the devices 52 to cause the devices 52 to grip one of the gloves 11 on the line 10 . After the glove has been gripped vacuum is then applied to the devices 52 to cause the devices 52 to separate thereby pulling the two layers 18 and 20 which make up the glove 11 away from one another to open the glove. At the same time as the vacuum is applied the pressure previously supplied to the devices 52 to cause gripping of the glove is released.
[0127] The glove is therefore held open with the frame 50 in the lower position at hand insertion station H shown in FIG. 11 so that a user can then insert his hand through front opening 62 of the housing 55 into the glove and the user simply draws his or her hand downwardly through the open bottom 64 of the housing 55 to tear the glove from the line 10 along the perforation 26 above the glove 11 . Thus, the user's hand is removed from the apparatus with the glove on place without the user having to touch the outside of the glove.
[0128] As is best shown in FIGS. 9 and 15 a light emitting array 66 is provided on the frame 50 opposite a linear array of photo detectors 68 . Light emitted by the emitters 66 is detected by the detectors 68 so that when a person's hand is located in the glove the light is blocked thereby providing an indication that a person's hand is in the apparatus and when the person tears the glove 11 from the line 10 by the downward movement of the hand previously mentioned, light is again detected by the array of photo detectors 68 . Thus, this provides a signal indicative of the fact that a user has inserted his or her hand into the apparatus and removed his or her hand with a glove on it. This signal is used to activate the linear bearings 56 to again drive the frame 50 upwardly. As the frame 50 is driven upwardly the friction between the line 10 and the rollers 58 causes the rollers 58 to rotate thereby rolling up relative to the station line 10 of gloves 11 . When the rollers 58 have rotated one full revolution as detected by the encoder 61 a signal is supplied to shut off the linear bearings 56 to prevent further upward movement of the frame 50 indicative of the fact that the frame 50 has returned to its starting station G shown in FIG. 10 . Rollers 58 grip the line 10 and the frame 50 moves downwardly back to the hand insertion station H shown in FIG. 11 where a glove is opened in the same manner as described above, ready for a user to insert his hand into the apparatus to locate the glove on the user's hand. Once this happens, and the user's hand is removed from the apparatus the sequence starts again and the frame 50 is driven upwardly so that the rollers rotate until the line is then gripped and the frame 50 moved downwardly to draw the line 10 from the roll 15 and open a fresh glove in the apparatus when the frame 50 returns to the station H as shown in FIG. 11 . Thus, the insertion of a user's hand into the apparatus and removal of the hand and glove provides the signal to operate the apparatus to open another glove ready for a user to place his hand into the glove. Thus, after a glove is removed from the line by a user a fresh glove is delivered to the hand insertion station H shown in FIG. 11 ready for another hand to be inserted into a glove.
[0129] It will be noted from the above that the rollers 58 only rotate during the upward movement of the frame 50 . During the lowering of the frame 50 the rollers 58 grip the line of gloves 10 and do not rotate thereby drawing further gloves from the roll 15 .
[0130] In order to facilitate rotation of the rollers 58 during movement of the indexing device 48 a driver is provided to rotate the rollers 58 during movement to the station G but which will allow the rollers to be locked against rotation during movement of the indexing device 48 back to the hand insertion station H. In one embodiment the driver comprises a motor 69 which has a clutch or ratchet mechanism so the motor can rotate the rollers during movement to the gripping station G but allow the rollers to remain locked against rotation during movement back to the hand insertion station H.
[0131] The motor 69 (see FIG. 9 ) is provided on the shaft 62 to rotate the roller 58 on that shaft with the rotation being imparted to the other roller by meshing engagement of the gears 59 .
[0132] In another embodiment as shown in FIG. 17 the driver comprises a gear 101 mounted on shaft 102 on which one of the rollers 58 is provided. The gear 101 meshes with a rack 103 fixed to housing 55 (shown in FIG. 16 ). The gear 101 is mounted to the shaft 102 via a ratchet, clutch or the like so that when the indexing device 48 is moved upwardly towards the gripping station G in the direction of arrow C in FIG. 17 the engagement of the gear 101 and the rack 103 causes rotation of the gear 101 and therefore the shaft 102 and roller 58 . Rotation is imparted to the other roller 58 by the gears 59 . Thus, the rollers 58 easily roll up the line 10 of the gloves 11 . During movement back towards the hand insertion station in the direction of arrow D the ratchet or clutch associated with the gear 101 allows the gear 101 to rotate freely on the shaft 102 so no rotation is imparted to the rollers 58 and the rollers remain in the locked position with the rib 70 located in the groove 71 as previously explained.
[0133] The provision of the gear 101 also provides the additional advantage in that it synchronises the upward movement of the indexing device 48 in the direction of arrow C with the rotation of the rollers 58 so the rollers undergo one full revolution during complete movement of the indexing device from the hand insertion station H to the gripping station G.
[0134] It will be appreciated from the previous description and drawings that the rollers 58 extend only part the distance of the space between the frame members 51 and therefore adequate space is provided for the motor 69 or the gear 101 and rack 103 .
[0135] As shown in FIG. 12 the rollers 58 are configured to grip the line 10 when the frame 50 is in the upper position shown in FIG. 9 . To achieve this one of the rollers 58 (i.e. the left roller in FIG. 12 ) is provided with a longitudinal rib 70 and the other roller 58 is provided with a longitudinal groove 71 . When the frame 50 is the upper position at gripper station G the rib 70 locates in the groove 71 therefore jamming the line 10 between the rib 70 and groove 71 so that the rollers 58 firmly hold the line 10 . When the frame 50 is moved downwardly the rollers 58 therefore firmly grip the line 10 and the line 10 is drawn off the roll 15 with downward movement of the frame 50 . When the frame 50 is moved upwardly, the rollers 58 are able to rotate so the rib 70 moves out of the groove 71 so that the rollers 58 can effectively roll up the line 10 for one full rotation of the rollers 58 until the rib 70 relocates in groove 71 to again grip the line 10 .
[0136] FIGS. 13 and 14 show in more detail the devices 52 according to a first embodiment for opening a glove 11 . The devices 52 are supported on plates 73 which form part of the frame 50 and extend between the frame members 51 . The plate 73 and the frame members 51 therefore form partial enclosures for securely supporting the devices 52 .
[0137] Each device 52 is identical and therefore only one will be described in detail in FIGS. 13 and 14 . Each device 52 comprises a open cell foam block 75 which is in the general shape of the glove 11 except that the fingers are somewhat shorter than the fingers of the glove 11 . The block 75 has a layer of lacquer or other sealant applied to edges 75 a , 75 b and rear surface 75 c . End edges 75 d and the edges which define the finger portions 75 e also have the lacquer or sealant coating applied to them. A vacuum tube 78 is connected with the block 75 and in turn connects with one of the pressure pumps 60 . A bladder 80 is connected on the outside of the block 75 against surface 75 c and again has the same general shape as the block 75 . The bladder includes a plastic strip 81 within the bladder which acts as a spring as will be described in more detail hereinafter. A supply tube 83 is connected to the bladder 80 and also to the other of the pumps 60 . Thus, one of the pumps 60 enables vacuum to be applied to the two devices 52 (namely the blocks 75 of the two devices 52 ) and the other pump 60 supplies pressure to the two bladders 80 of the devices 52 .
[0138] In order to open the glove 11 air is pumped from one of the pressure pumps 60 into the bladders 80 to cause the bladders 80 to expand. The spring generally holds the bladders 81 against spherical expansion of the bladders 80 and therefore when the bladders expand they push against the blocks 75 to push the blocks 75 into engagement with a closed glove 11 as is best shown in FIG. 10 . Thus, the open porous faces 75 g of the blocks 75 , which do not have lacquer or sealant applied to them, are pushed into gentle contact with the layers 18 and 20 which make up the glove 11 . Vacuum is then drawn by the other pump 60 through the tube 78 and through the open cellular structure of the foam block 75 so that the webs 18 and 20 are sucked against the surface of 75 g of the blocks 75 . At the same time, pressure is released from the bladders 80 causing the bladders to return to their generally flat deflated configuration shown in FIG. 14 pulling the block 75 with them in the direction of arrows A in FIG. 13 . This thereby cause layers 18 and 20 to separate and open the glove 11 sufficient for a person to insert his or her hand into the glove 11 through open door 62 of the housing 55 .
[0139] FIGS. 18 to 20 show the devices 52 of an alternative embodiment for opening the glove 11 . The devices are supported on plates 73 , best seen in FIG. 17 , which form part of the frame 50 and extend between the frame members 51 shown in FIGS. 9 to 15 . The plate 73 and the frame members 51 therefore form partial enclosures for securely supporting the devices 52 .
[0140] Each device 52 is the same and therefore only one will be described in detail. Each device 52 comprises a bellows 75 having a clamping ring 120 for securing the bellows 75 to the plate 73 , a flexible and inflatable diaphragm 121 having a side wall comprising a series of the folds and an engagement face 122 that approximates the size of the palm region of the glove 11 . Arranged about the perimeter of the engagement face 122 is a vacuum sealing lip 123 and central of the engagement face 122 are three suction holes 124 that are each connected to a vacuum source 60 a via a manifold and tubing 78 a . The diaphragm 121 of the bellows 75 is connected to an air delivery system comprising an air displacement pump 60 b . FIG. 19 shows an embodiment in which the vacuum source 60 a and air displacement pump 60 b are in the form of piston and cylinder assemblies located within rollers 58 for guiding the line 10 of gloves 11 . The inside of walls of the rollers 58 form the cylinder and a piston 126 having vacuum seals 125 or pump seals 128 and each is driven inside the cylinders by a solenoid controlled linear actuator 127 . The end wall of each roller 58 is equipped with a rotary air coupling for coupling to air supply tubing 78 a , 78 b . In the case of the vacuum source, tubing 78 a connects the cylinder of the vacuum source to the holes 124 in the face of the engagement face 122 via a manifold. In the case of the air displacement pump, tubing 78 b connects the cylinder to the inside of the diaphragm 121 .
[0141] In order to open the glove 11 the liner actuator 127 of the air pump 60 b is operated to move the piston to the distal end of the roller 58 and thereby expand the bellows 75 in the direction of arrows A in FIG. 18 until the lip sealing formation 123 engages the palm region of a glove 11 at the insertion station H. Pressure release valves or flow regulates may be incorporated into the air pump 60 b or the tubing 78 b to limit over pressurisation or under pressurisation of the bellows 75 as deemed necessary. With the bellows 75 expanded and lip formations 123 contacting opposite layers or sides of the glove 11 , the vacuum source 60 a is operated to retain the each respective layer of the glove 11 to the bellows 75 . The linear actuator 127 of the vacuum 60 a is operated by moving the piston toward the proximal end of the roller 58 in FIG. 19 . Once the formation of an adequate vacuum has been established to retain the layers of the glove 11 to the engagement face 122 , the linear actuator 127 of the air displacement pump 60 b drives the piston from the distal end to proximal end of the cylinder, thereby deflating the bellows 75 and simultaneously opening the glove ready for hand insertion. The adequacy or inadequacy of inflation and deflation of the bellows 75 can be monitored by way of the pressure release valves or flow regulators. Similarly, the adequacy or inadequacy of the vacuum for retaining the layers of the glove 11 to the engagement face 122 of the bellows 75 can be monitored using suitable regulators.
[0142] Irrespective of whether the devices 52 for opening the glove are in the form of the embodiment shown in FIGS. 13 and 14 , or the alternative embodiment shown in FIGS. 18 and 20 , insertion of a hand into the glove blocks the light from the emitter array 66 to the detector array 68 indicating a hand has been placed in the glove. As previously explained, the user then pulls his or her hand downwardly through open bottom 64 to tear the glove 11 along perforated line 26 with the glove on the user's hand. As the user's hand is removed from the apparatus light is again detected by the array 68 providing a signal for the frame 50 to be driven upwardly to again grip the line and move downwardly with another glove being opened as the frame 50 moves downwardly so that a user can insert his or her other hand into the next glove if desired. Otherwise, the glove is simply held in the open configuration in the device awaiting for the next hand to be inserted into that glove and for that glove to be torn from the line 10 before the sequence repeats to bring another glove to the hand insertion station H.
[0143] Vacuum may be applied to hold a glove in the open position at the insertion station H for a predetermined time interval after which the vacuum is shut off. Thus, if a glove is not required for some time, the glove merely remains in a static position at the hand insertion station. A sensor (not shown) may be provided to activate the glove opening device to open the glove again when a hand is inserted into the apparatus.
[0144] In another embodiment the cycle of retrieving a new glove and opening a new glove may be commenced by a start button 110 (see FIG. 15 ) and the sequence of operation may be that when the button 110 is pushed the indexing device 48 moves upwardly as previously explained to grip the line 10 and then moves back to the hand insertion station with the glove being opened as previously explained so the user can insert his or her hand into the glove. When another glove is required the button 110 is again pushed so the sequence repeats itself. This prevents the need to hold vacuum at the opening devices 52 for a great length of time.
[0145] As is best shown in FIG. 15 , the housing 55 is provided with a door 90 which can be opened in the direction of arrow B to enable a new roll 15 to be loaded into the apparatus. To load a new roll the door 90 is opened and the remnants of the old roll 15 removed. A new roll is located in place in the apparatus. When the door 90 is opened, a mechanical linkage schematically shown at 91 causes two pins 92 to be driven forward. The locating holes 33 in one of the panels 25 of line 10 are located on the pins 92 so the pins 92 project through the holes 33 . This correctly registers the roll relative to the rollers 58 and part of the line 10 is located between the rollers 58 . To facilitate location of the line 10 between the rollers 58 one of the rollers 58 is mounted on a spring tensioning device 95 which, when the door 90 is opened, draws the respective roller 58 away from the other roller 58 to provide a space for the line 10 to be easily inserted between the rollers. Again a mechanical link 96 (schematically shown) may be used to achieve this. When the door 10 is closed the pins 92 are retracted out of the holes 33 away from the line 10 and the roller 58 is again spring biased against the other roller 58 with the line 10 between the rollers 58 .
[0146] When the door 90 is closed the apparatus can be operated to locate a glove at the hand insertion station with the glove open ready for use by a user.
[0147] FIG. 18 is a schematic block diagram of the control system for controlling the apparatus. A processor 99 is provided which receives signals from the encoder 61 to monitor the position of the rollers 58 relative to one another and to stop movement of linear bearings 56 when the rollers 58 have rotated one full revolution. Photo detector array 66 and 68 also provide signals to the processor 99 to indicate location removal of a user's hand to drive the linear bearings 56 to move the indexing device 48 upwardly and then back down to the hand insertion station H and at the same time operate the pumps and/or vacuum source to apply pressure and vacuum to the devices 52 to grip the glove and open the glove. In the event that the pressure release values or air regulators detect that inadequate or excessive air flow is created by pumps 60 , 60 a or 60 b , causing malfunction of the devices 52 , the processor 99 can activate an alarm 130 signalling that the apparatus requires maintenance or servicing.
[0148] The processor 99 also receives a signal when the button 100 is pressed, should the button be provided, to commence the glove retrieval and opening sequence, and a signal from timer 111 for shutting off the vacuum to the opening devices 52 after a predetermined time period.
[0149] If a motor 69 is provided for facilitating rotation of the rollers 58 during upward movement of the frame 50 the processor 99 can also control the motor 69 to drive the roller 68 during movement of the indexing device 48 from station H to station G until one full rotation of the rollers 58 has occurred.
[0150] Other sensors may also be included in the apparatus to detect the location of the line 10 and is indexing through the apparatus from the roll 15 to the hand insertion station. Further markings or other indicia may be provided on the line 10 to facilitate detection of the line 10 by the other sensors.
[0151] In order to provide additional rigidity to the line 10 of the gloves 11 , the layers 18 and 20 may be provided with additional rigidity such as by forming a double heat seal about the periphery of the glove 11 or providing a thickened heat seal bead along the line 11 . The additional rigidity will assist in ensuring that the line 10 moves vertically downwardly and does not tend to wrap around the rollers 58 during indexing of the line 10 through the apparatus.
[0152] Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.
[0153] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
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The present invention relates to a package of disposable gloves and to a method and an apparatus which can use the package to enable the gloves to be applied to a user's hands. The gloves are stored in a roll and are unrolled and opened by the apparatus so that a user can hygienically insert their hand into a glove without touching the glove. The user, with their hand in the glove can then sever the glove from the roll of gloves by moving their hand downwardly and away from the apparatus. The apparatus can then unroll and open another glove for the user to insert their other hand.
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GRANT INFORMATION
The development of the invention was supported by the National Institute of Dental Research through Research Grant Number 1R01 DE-04814.
BACKGROUND OF THE INVENTION
Prosthetic dentures currently in use typically consist of a baseplate of hard poly(methyl methacrylate) which supports the artificial teeth needed for chewing and for esthetics. Many patients have difficulty tolerating a hard denture so there is a need for a soft denture liner affixed to the denture base to cushion the soft tissue. A number of criteria have been established for materials to be useful as denture liners, notably non-toxicity and non-allergenicity. The best materials should be permanently resilient, inert, cleanable, and substantially water-insoluble, and have low water-sorption characteristics and good tensile strength. While softness is desirable for comfort, the liner material must be sufficiently firm to displace the soft tissues of the mouth and to allow grinding of the denture periphery to avoid creating sore spots; additionally, the liner material must be permanently bondable to the denture base material. It is also highly preferably from a practical standpoint that the lined denture be capable of fabrication under conditions generally found in dental laboratories, or in a dentist's office, avoiding extremes of temperature and pressure conditions, or the use of special equipment.
Several liner materials have been proposed which satisfy these criteria sufficiently to be useful, such as silicone rubber, plasticized poly(methacrylates), polyurethanes, and polyvinyl chlorides. An especially useful liner material is disclosed in U.S. Pat. No. 4,251,215 issued on Feb. 17, 1981 to May et al., comprising phosphonitrilic fluoroelastomer (poly(fluoroalkoxy)phosphazene) which exhibits particularly good resiliency, water-sorption, and biocompatibility characteristics. The fluoroelastomer liner materials exemplified therein, however, have been found to be somewhat deficient with respect to tensile strength, hardness, and bondability to denture base material, as compared to the theoretical ideal. Further, the process for forming the denture as described in the May et al. patent is a two-step process which requires the liner and denture base to be separately cured, and additionally requires the use of strong bonding agents, as well as the use of temperatures in excess of 100° C. (boiling point of water at atmospheric pressure) for curing the liner. The fabrication of this prior art composite denture thus requires somewhat elaborate equipment, and cannot be conveniently accomplished in an average dental office or laboratory.
SUMMARY OF THE INVENTION
The invention accordingly provides a denture liner composition based on phosphonitrilic fluoroelastomers (poly(fluoroalkoxy)phosphazenes) which, when cured by cross-linking of pendant groups, retain the excellent liner properties of the fluoroelastomer base material, while exhibiting improved hardness, tensile strength, grinding and adjusting ability, and bond strength characteristics. The denture liner composition is curable at or below temperatures of 100° C. at atmospheric pressure, and retains its dimensional stability during curing. Thus, according to the process of the invention, the composite denture is formed by curing the shaped liner material in situ, placed directly against a conventional denture base material, conveniently by immersing the packed denture flask in an open water bath at boiling temperatures. The method improves the bond strength of the finished composite denture, and obviates the use of potentially harmful bonding agents such as sulfuric or perfluoroacetic acid or epoxy or urethane adhesives. Most importantly, the method avoids the use of high temperatures and/or pressurized equipment, and can thus be used in average commercial dental laboratories or even in the average dentist's office. Additionally, the use of low temperatures avoids vaporization of monomers such as methyl methacrylate, and prevents dehydration of the liner material during curing. Dehydration necessitates rehydration of the liner prior to use in the intended aqueous environment, and the dehydration/rehydration steps may cause undesirable dimensional changes in the liner as well as the substrate denture base.
Broadly, the composition of the invention comprises a phosphonitrilic fluoroelastomer and interpenetrating lower alkyl methacrylate monomer to improve hardness of the product liner and bond strength of the fluoroelastomer to the denture base. The composition preferably further includes a dimethacrylate glycol ester cross-linking agent such as polyethylene glycol dimethacrylate, 1,6-hexamethylene glycol dimethacrylate, ethylene glycol dimethacrylate, or tetraethylene glycol dimethacrylate to improve tensile strength and bond strength of the product liner. Filler particles such as particles of a hard acrylic resin, silica, Al 2 O 3 , diatomaceous earth, or BaSO 4 are also optionally included to increase hardness. The composition further includes curing additives to facilitate curing of the liner material at temperatures at or below 100° C., particularly benzoyl peroxide or lauroyl peroxide as free-radical initiator and MgO as an acid scavenger. The following materials, in admixture, are within the scope of the invention:
______________________________________ Percent by Wt. ofMaterial Total Composition______________________________________Phosphonitrilic fluoroelastomer 30 to 98Filler 0 to 30Interpenetrating monomer 1 to 40Cross-linker 0 to 20______________________________________
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a SEM photomicrograph (50x original magnification) illustrating a 180° peel test on a PNF-200 dental liner composition without filler.
FIG. 2 is similar to FIG. 1, illustrating a 180° peel test on a PNF-200 dental liner composition with BaSO 4 filler.
FIG. 3 is similar to FIG. 1, illustrating a 180° peel test on a PNF-200 dental liner composition with PMMA filler.
DETAILED DESCRIPTION OF THE INVENTION
The dental liner composition of the invention is based on phosphonitrilic fluoroelastomers (poly(fluoroalkoxy)phosphazenes) of the type described in U.S. Pat. Nos. 3,702,833 and 3,888,799, both to Rose et al. The polymers are characterized by repeating units of the general formula ##STR1## wherein X is H or F, and n is usually from 1 to 11. Such elastomers are commercially available, and are typified by PNF-200, available from Firestone Central Research Laboratories, 1200 Firestone Parkway, Akron, Ohio. This material is represented as ##STR2## wherein n is 3, 5, 7, 9, or 11, and m is from 10,000 to 50,000, and described as a thermoset having the following properties:
______________________________________Color AmberSpecific Gravity 1.75 to 1.85Mooney Viscosity 15Solvents Ketones, THF, DMFGlass Transition Temperature -68° C. (-90° F.)Durometer A Hardness 35-90Tensile Strength 1000-2000 psi100% Modulus 400-2000 psiElongation 75-250%Tear Resistance to 250 ppi______________________________________
Preferably, the fluoroelastomer is purified by extraction and coagulation from methanol in a known manner prior to biomedical use in the liner composition.
The elastomer is employed in amounts of from about 30% to about 98% by weight of the total composition, usually from about 30% to 60% for a firm liner material, and from about 40% to about 95% for a soft liner material.
According to the invention, the fluoroelastomer is compounded with interpenetrating methacrylate monomers comprising C 1 -C 6 alkyl methacrylate monomers such as cyclohexyl methacrylate, butyl methacrylate, or, especially, methyl methacrylate monomer (MMA), which unexpectedly improve bond strength and tensile strength, and provide good hardness and elongation in the liner material. The interpenetrating monomers are compounded with the fluoroelastomer gum in an amount of from about 1% to about 40% by weight of monomer, based on the weight of the total composition. Preferably, the monomer is compounded with the elastomer by incorporating a sufficient amount of fluoroelastomer into the liquid monomer to form a viscous syrup; the syrup is then incorporated into the remainder of the fluoroelastomer as by milling, conveniently on a low speed mill such as a Farrel rubber mill, without heating. Alternatively, the monomer may be placed in an airtight container (to prevent evaporation of the monomer) for a period of from about 48 to 72 hours, or until the monomer has completely interpenetrated the elastomer. Additional monomer may be added to increase firmness, if desired, or monomer may be evaporated for a softer product.
In one embodiment of the invention, the liner composition further includes a cross-linking agent compounded with the monomer and fluoroelastomer gum comprising a dimethacrylate glycol ester cross-linking agent, preferably ethylene glycol dimethacrylate (EGDMA), in order to improve tensile and bond strength of the liner product. Generally, an amount of cross-linking agent of from about 0% to about 20%, preferably from about 1% to about 12.5%, by weight of the total composition is employed, with amounts at the lower end for a soft product and at the higher end for a firm product. The effects on bond strength of PNF-200 obtained with a series of methacrylate cross-linking agents, stoichiometrically adjusted for bonding sites, are set forth in Table I. All the dimethacrylates tested usefully improved bond strength, while a significant improvement in bond strength was obtained with EGDMA. All bond strength tests were conducted according to ASTM D 903.
TABLE I______________________________________Methacrylate Cross-linker Wt % N Bond Strength N/m______________________________________Control (PNF-200) -- 5 1280 *n-Lauryl Methacrylate 10 4 1140Polyethylene Glycol 200 12 3 1670Dimethacrylate1,6-Hexamethylene Glycol 10 5 1810 *DimethacrylateTetraethylene Glycol 8 4 2160 *DimethacrylateEthylene Glycol 10 5 3590Dimethacrylate (EGDMA)______________________________________ *NSD at P ≦ 0.05, Scheffe
The adhesion of PNF-200 compounded with 10% EGDMA is illustrated in FIG. 1, showing the peel zone wherein the liner has been peeled from the denture base in the cured composite denture.
The improved bond strength and firmness obtained with both EGDMA and MMA is set forth in Table II (all amounts are in percent by weight of total composition).
TABLE II______________________________________ Hardness *Bond StrengthPNF MMA EGDMA (Durometer A) (N/m)______________________________________58 36 -- 13.4 383551 36 8.6 38.6 7250______________________________________ *ASTM Peel Test, scaled.
Tensile strengths of about 7.0 MPa and 406% elongation have been achieved.
The liner composition of the invention further may include a filler material homogeneously admixed with the purified fluoroelastomer gum. If a filler is employed, the filler is first preferably dispersed in the interpenetrating monomer, prior to compounding with the fluoroelastomer. A portion of the fluoroelastomer, typically about 10% by weight, is then incorporated into this dispersion to form a syrup, as previously described. A very uniform dispersion of the filler particles is thus obtained after milling the remainder of the elastomer with the syrup. A particularly rapid compounding is obtained if a portion of the monomer is employed to pre-soften the remainder of the elastomer. In dentures prepared according to the process of the invention wherein the liner material is cured in situ on the denture base material, the filler particles significantly increase the strength of the bond between the liner and base owing to stiffening of the rubber or the mechanical interlocking of these particles with the liner and base material during curing; (see FIGS. 1-3). Particles comprising beads or fibers are suitable, and it is generally preferable that the particles be compatible with the denture base dough to promote adhesion during the curing process. LUCITONE 199 beads or fibers, obtainable from the L. D. Caulk Company (a division of Dentsply International, Inc.), Milford, Del., are exemplary acrylic particles useful in the composition of the invention. These particles are derived from a hard poly(methyl methacrylate) resin, and are particularly useful in conjunction with LUCITONE 199 denture base acrylic dough, a partially-cured grafted poly(methyl methacrylate) thermoset, similarly obtainable. Other fillers or extenders that may be included comprise hydrophobic amorphous silica of very small particle size. These materials reduce the amount of PNF required, increase hardness, and may improve bond strength. Two examples of these fumed silica fillers/extenders are Quso WR-542, PQ Corp., Valley Forge, PA., a silica washed with silicone oil, and Tullanox 500, Tulco, No. Billerica, MA, a silica coated with trimethyl chlorosilane. A particularly useful filler material is barium sulfate, which renders the dental liner radiopaque and detectable on radiographs if a portion should be swallowed or inhaled. (see FIG. 2).
The amount of filler material employed in the liner composition will vary according to the desired hardness of the finished liner material. While large amounts of poly(methyl methacrylate) particles (up to 28% by weight of the composition) were found to result in decreased elongation, increased amounts of filler over about 10% by weight of the composition had little effect on bond strength or tensile strength (Table IV), while effecting a more or less proportional increase in firmness of the finished product. Accordingly, useful amounts of polymeric filler are from about 7% by weight of the composition, for a soft product, to about at least 30% by weight of the composition for a firm product. Preferably, from about 0% to about 10% by weight of inorganic filler is employed for a soft product, and most preferably, about 0-5% by weight for a soft product and about 10-20% by weight for a firm product, depending on which filler is used.
The effect of various fillers on tensile strength, elongation, and hardness of a PNF-200 control is set forth in Table III, infra. All the fillers decreased tensile strength. Increased bond strength of a PNF-200/PMMA composition is summarized in Table IV, infra, and illustrated in FIG. 3, showing the "peel zone" wherein the filled PNF-200 liner has been peeled from the poly(methyl methacrylate) denture base after curing. Adhesion is imparted by mechanical interlocking of the elastomer around the PMMA beads, which in turn are locked into the polymerized denture base dough. The peel test employed is the Wright characterization of the adhesion of soft lining materials to poly(methyl methacrylate) (J. Dent. Res. 61:1002-1005, 1982).
TABLE III______________________________________ Tensile Duro- Wt Strength Elongation meter AFiller Agent % N (MPa) (%) Hardness______________________________________Control (PNF-200) 0 5 1.5 171 17 *Aluminum Oxide 20 5 0.27 125 25Silanized Syloid 20 5 0.61 282 45Diatomaceous Earth 20 5 0.81 598 --Poly(methyl meth- 10 5 * 0.82 740 38acrylate) (PMMA)______________________________________ *NSD P ≦ 0.05, Scheffe
The effects of varying amounts of EGDMA and PMMA beads on bond strength, hardness, tensile strength and elongation of the dental liner composition are set forth in Table IV. EDGMA cross-linker significantly improves bond strength, especially in amounts of about 10% by weight of the composition, and further improves tensile strength, especially in amounts of about 20% by weight of the composition. Unfavorable losses in tensile strength owing to the presence of filler in the liner composition are compensated by the presence of dimethacrylate cross-linker in suitable amounts.
TABLE IV__________________________________________________________________________ Durometer Tensile Elonga-EGDMAPMMA Bond Strength A Strength tion(Wt %)(Wt %) N (N/m) Hardness (MPa) N (%)__________________________________________________________________________ 0 0 5 1280 17 1.5 5 171 ----2010 5 28 7------ 44454 ##STR3## 16101420298035902750 ##STR4## 5538554843 ##STR5## 0.770.873.11.81.3 44444 368740428489674__________________________________________________________________________ *NSD P ≦ 0.05, Scheffe
The effects of EGDMA and PMMA beads on tensile set of PNF-200 is set forth in Table V.
Tensile set was measured by straining flat tensile bar specimens 50% and then holding them either dry or in Silverstone's artificial saliva for 10 3 seconds. The specimen was then released and allowed to recover. Tensile set was measured at 10 3 seconds and 8.6×10 4 seconds (24 hours) as shown in Table V. It is readily apparent that the addition of 28% PMMA greatly reduces tensile set, but EGDMA had no effect as an additive to PNF-200.
TABLE V______________________________________ PNF-200 PMMA Beads EGDMATensile Set in %, n = 7 to 10 7% 28% 5% 10% 20%______________________________________Unrecovered Elongation 18.9* 7.6 19.3* 20.4* 19.1after 10.sup.3 secUnrecovered Elongation #6.9* 3.6 6.9* 7.6* 7.5after 8.6 × 10.sup.4 sec(24h)______________________________________ NSD, P ≦ 0.05 between samples in each row. ASTM D 412, in artificial saliva # Dry
In addition to the filler materials, monomers, and dimethacrylate cross-linking agents, other components commonly incorporated into dental liners may be compounded with the fluoroelastomer base. In particular, pigments making the liner more visually acceptable may be used, such as iron oxide based pigments, and Cd-S-Se pigments.
The composite denture of the invention is broadly formed by compounding fluoroelastomer with the components of the dental liner composition as previously described, pressing the resulting composition into a wafer, and molding after removal of a spacer to a denture base dough packed in a customary mold flask; the composite denture is then heat-treated to cure the liner and the denture base dough together to provide a lined denture. In an exemplary procedure, the ingredients are milled at least ten minutes on a cold rubber mill, and the liner composition is then pressed flat into sheets of the desired thickness, generally about 2 mm to 3 mm. A denture waxing is boiled out of a flask in the usual fashion, and fresh denture base dough is packed. A 1 to 2 mm spacer is placed on the tissue side of the mold cavity, with polyethylene sheet spacers in place, and the denture flask trial-packed several times. Sheets of the soft liner composition are then laid against the base material, cut to shape, and the flask is again trial-packed. The denture flask is then closed under pressure (about 20.7 MPa), and the composite denture is heat-treated to cure the base and liner material, for example, first at 73° C. for 1.5 hours, and then at 100° C. for up to about 1.5 hours.
In one advantageous embodiment of the invention, a wafer of firm liner material is completely laid over the base material dough and trial-packed; the central area of the liner over the alveolar ridges is outlined and cut away. Soft liner material is then laid in the cut-away central area, and the flask is again trial-packed. The composite denture is then heat-cured. This embodiment provides a firm, creep-resistant, higher-strength material at the periphery of the denture which is polishable, adjustable, and properly displaces underlying soft tissue, while providing a soft, creep-deformable lower-strength material forming a soft cushion at the center of the denture over the bony structures of the jaw.
While this process provides good bond strength between the denture liner and denture base, it is advantageous to maximize adhesion between the components of the composite denture, in the finished product. A particularly suitable method is to liberally apply acrylic monomer between the liner and base material prior to curing. A particularly preferred monomer for use with PMMA dough is methyl methacrylate (MMA), for example, LUCITONE 199 denture base monomer.
In a particularly preferred embodiment of the process of the invention, a known free radical initiator such as lauroyl or benzoyl peroxide and an acid scavenger such as magnesium oxide are incorporated into the liner composition. The use of each of these materials in amounts of from about 1% to 2% by weight of the total composition permit the curing of the composite denture at temperatures of 100° C. or less, conveniently by placing the packed flask in a water-bath at atmospheric pressure. The exact conditions will depend on the particular materials employed; however, for a PMMA dough denture base of the type described herein, curing at 73° C. (165° F.) for at least one and one-half hour, followed by bringing the temperature of the water bath to 100° C. (212° F.) for a period of time up to about one and one-half hour, has been found suitable. While pressures inside the flask are initially about 3000 psig, pressurized vessels are not necessary for effecting a cure of the product.
EXAMPLE I
A soft denture liner according to the invention is prepared in the following manner:
880 g. phosphonitrilic fluoroelastomer (PNF-200) is extracted and coagulated from methanol solution to eliminate impurities, and 10 g. lauroyl peroxide added as chain initiator. The initiator is then milled into the elastomer on a rubber mill until the material appears homogeneous, and 10 g. MgO as acid scavenger are added. The material is again milled until a homogeneous mixture is obtained. 50 g. poly(methyl methacrylate) filler powder (LUCITONE 199 beads and fibers) and 50 g. ethylene glycol dimethacrylate (EGDMA) are then milled into the rubber compound. All milling is done at room temperature.
The milled PNF soft liner material is pressed into a sheet 2 to 3 mm thick using an aluminum mold and polyethylene separators, at 34.5 MPa (5000 psig) for about 15 minutes. The sheet is then cut to size with scissors for application to a poly(methyl methacrylate) denture base dough (PMMA dough) in a denture flask.
The formed liner and denture base dough are each liberally brushed with methyl methacrylate monomer on their bonding surfaces, and PNF soft liner material is trial-packed in the denture flask until the desired conformation is obtained. Firm liner material may be retained at the periphery of the denture but removed from the center, and soft liner material placed over areas of bony anatomy. The liner is then final-packed at 20.7 MPa (3000 psig) in preparation for curing. Following packing, the liner composition and denture base are cured by immersing the flask in a water bath for 90 minutes at 73° C. (165° F.); the water is then brought to a boil and curing continued for up to an additional 90 minutes. The cured composite denture is then cooled and removed from the flask. The adhesion imparted by the poly(methyl methacrylate) filler powder is illustrated in FIG. 3, showing the peel zone wherein the liner has been peeled from the denture base of the cured composite denture.
EXAMPLE II
A dental liner composition comprising 58 parts of the PNF-200 phosphonitrilic fluoroelastomer compounded with lauroyl peroxide and MgO (no filler or EGDMA) from Example I, and 36 parts methyl methacrylate monomer (MMA) was prepared in the following manner:
8 parts of the compounded PNF-200 were dissolved in the MMA by stirring to form a viscous syrup. The syrup was then rolled into the remainder of the PNF on a low-speed Farrel rubber mill, without heating, until a homogeneous product liner material was obtained. The material was then packed and cured as described in Example I. Physical characteristics of the resultant product are given in Table II, supra.
EXAMPLE III
The procedure of Example II was followed, except 8.6 parts of ethylene glycol dimethacrylate (EGDMA) were first dispersed in the liquid monomer, prior to incorporation of 8 parts PNF. Physical characteristics of the product liner material, packed and cured as described in Example I, are also given in Table II. Adhesion of the dental liner to the cured composite denture is illustrated in FIG. 1, showing the peel zone wherein the liner has been peeled from the denture base.
EXAMPLE IV
A firm dental liner composition was prepared from the following materials (all amounts are expressed in % wt. of total composition):
______________________________________ Pigment LauroylPNF MMA EGDMA BaSO.sub.4 MgO (Cd--S--Se) Peroxide______________________________________32.2538.75 6.0 20.0 1.5 Trace 1.5______________________________________
The EGDMA, lauroyl peroxide, MgO, barium sulfate, and the pigment were evenly dispersed into the methyl methacrylate monomer, using a blender. To this dispersion was added about 8% of the total amount of PNF to form a viscous syrup of about the consistency of maple syrup. The syrup was milled into the remainder of the PNF to form a homogeneous liner composition, which was packed and cured as in Example I. The cured liner had the following characteristics:
______________________________________Tensile DurometerStrength Elongation A Bond Strength(MPa) % Hardness (N/m)______________________________________1.65 174 43 4482______________________________________
The adhesion imparted by BaSO 4 to the liner composition is illustrated in FIG. 2, showing the peel zone wherein the liner has been peeled from the denture base of the cured composite denture.
EXAMPLE V
The procedure of Example IV was followed, except 30% by volume of the MMA was reserved to pre-soften the remainder portion of the PNF. Process time for compounding the PNF and syrup was significantly shorter to achieve a homogeneous product.
EXAMPLE VI
A soft dental liner composition was prepared according to Example IV using the following materials (all amounts are expressed in percent by weight of total composition):
______________________________________ Pigment LauroylPNF MMA EGDMA BaSO.sub.4 MgO (Cd--S--Se) Peroxide______________________________________46.2538.75 2.0 10.0 1.5 Trace 1.5______________________________________
The cured liner had the following characteristics:
______________________________________Tensile DurometerStrength Elongation A Bond Strength(MPa) % Hardness (N/m)______________________________________1.44 307 21 3604______________________________________
While the application has discussed crosslinkers of dimethacrylates, the use of diacrylates are also contemplated.
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The invention provides a denture liner composition for a composite denture based on a phosphonitrilic fluoroelastomer (poly(fluoroalkoxy)phosphazene) curable at atmospheric pressure at temperatures of 100° C. or less, conveniently by immersing the packed denture flask in a water bath at the appropriate temperature. The composition includes filler materials for increasing the hardness of the cured liner, interpenetrating polymers for increasing firmness and bond strength, and cross-linking agents for increasing the tensile strength and bond strength of the cured liner. The composite denture is preferably prepared in a one-step process wherein the liner composition material of a single firmness is cured in situ with the denture base material. Alternatively, a firm liner material may be cured at the periphery of the denture and a softer liner material cured at the center, in order to provide a firm elastic liner where adjustments must be made by grinding and where the patient's soft tissues must be displaced, and a soft elastic liner over the bony anatomy of the patient where stresses from chewing are most concentrated and the soft tissues are thin.
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FIELD OF THE INVENTION
The present invention relates to a decoding apparatus and method for encoded data of still images and moving images.
BACKGROUND OF THE INVENTION
Conventionally, a scheme using an entropy coding technique using a variable-length code is well known as one compression coding technique of still images and moving images. This technique is also adopted in JPEG (Joint Photographic Expert Group) as an international standard. In recent years, especially, many hardware implementation means using a Huffman code table as a variable-length code have been proposed. Such prior art will be explained below.
A conventional decoding apparatus comprises a shift means which comprises a circuit capable of shifting input encoded data for respective bits, a decoder for obtaining the code length and frequency of generation of a head code output from the shift means by comparing the encoded data output from the shift means and a pre-stored minimum or maximum code word of each code length, a symbol memory for storing decoded data (symbol data) in the order of frequency of generation, an additional bit processor for executing an additional bit process, and a shift amount select means for controlling a shift amount of the shift means.
The shift amount select means selects, as the shift amount of the shift means, the code length obtained by the decoder in an odd cycle, and an additional bit length output from the symbol memory in an even cycle. In this example, the throughput of the decoding process is always 0.5 symbols/cycle. In addition, the following technique for improving the throughput of the decoding process is known.
In this technique, a decoding apparatus comprises two different decoders, and a first decoder executes the same process in the aforementioned decoder. On the other hand, a second decoder pre-stores code words with high frequencies of generation and symbol data corresponding to these code words, and outputs symbol data in one cycle for a code word with a high frequency of generation.
For other code words, the first decoder generates an address of the symbol memory, and outputs symbol data output from the symbol memory in the next cycle as decoded data. According to this example, a throughput of a maximum of 1 symbol/cycle can be obtained.
In order to realize a high-speed decoding process, a specific decoding means must be implemented as hardware and the circuit must be operated at high frequency. However, the conventional apparatus suffers the following problems.
Conventionally, since an additional bit processing means is unknown in the decoding process, it is difficult to attain hardware implementation. Especially, when a process is done at the throughput of a maximum of 1 symbol/cycle, since the additional bit processor must at least cope with this processing rate, a hardware implementation means of the additional bit processor is very important upon realizing a high-speed circuit.
When two different blocks (second decoder and symbol memory) output decoded data depending on input encoded data, since their latencies (execution times) are different, the input timings of symbol data to a selector deviate from each other. Hence, control that considers this timing deviation is required, resulting in complicated control.
It is hard to implement a pipeline process. Even if code lengths corresponding to the code words stored in the second decoder are stored in advance and a code length corresponding to a selected code word is shifted out from the shift means in one cycle to solve the aforementioned problem, since the output from the decoding apparatus is one cycle, an arithmetic operation for the decoding process, e.g., an additional bit arithmetic operation must be done in one cycle, and it is difficult to realize a pipeline structure in synchronous circuit design.
In order to achieve efficient, high-speed processes, the processing unit must be shifted for each encoded data. However, conventionally, the shift amount control of the input means to the decoding apparatus is unknown.
FIG. 11 shows the arrangement of a variable-length decoding apparatus as prior art 1 . This decoding apparatus comprises a shift-out means (to be referred to as “shift” hereinafter) 1201 that comprises a circuit capable of shifting input encoded data for respective bits, a decoder 1203 for obtaining the code length and frequency of generation of a head code output from the shift 1201 by comparing the encoded data output from the shift 1201 and a minimum or maximum code word of each code length, which is stored in advance, a symbol memory 1205 for storing decoded data (symbol data RRRR/SSSS) in the order of frequency of generation, an additional bit processor 1202 for executing an additional bit process, and a shift amount select means 1204 for controlling the shift amount of the shift 1201 .
The shift amount select means 1204 selects, as the shift amount of the shift 1201 , the code length obtained by the decoder 1203 in an odd cycle, and an additional bit length output from the symbol memory 1205 in an even cycle.
FIG. 12 shows the arrangement of prior art 2 which can improve the throughput of the decoding process in addition to the decoding apparatus of prior art 1 . In this prior art, a high-speed symbol decoder 1352 executes a high-speed decoding process of a plurality of selected symbols, and a symbol decoder 1353 decodes other symbols. As an example of a select means of symbols to be decoded by the high-speed symbol decoder 1352 , a plurality of symbols in descending order of frequency of generation, or symbols with zero runlength may be selected.
A characteristic feature of prior art 2 lies in that priority is given to the decoding process of the high-speed symbol decoder 1352 . If input encoded data hits a code word corresponding to a symbol registered in the high-speed symbol decoder 1352 , the decoding result of the high-speed symbol decoder 1352 is preferentially selected as an output.
FIG. 13 shows prior art 3 as a technique for further improving the throughput of prior art 2 . A variable-length decoding apparatus according to prior art 3 comprises a 1-code word decoder 1403 for decoding a head code word, and a 2-successive code word decoder 1402 capable of decoding a successive sequence of two ode words from the head with high frequency of generation, and is characterized in that priority is given to the 2-successive code word decoder 1402 . If a hit has occurred in the 2-successive code word decoder 1402 , since two code words can be decoded at one time, the throughput can be further improved.
As the encoded data sizes of still images and moving images increase, the required processing performance for an encoding processing apparatus becomes considerably high. Especially, since the variable-length decoding apparatus must decode a variable-length code, it is very difficult to improve the throughput. For this reason, various solutions have been proposed so far, but the following problems remain unsolved.
The throughput varies depending on the hit ratio of the high-speed symbol decoder 1352 . Even if all data hit, the performance of a maximum of only one symbol per decoding sequence is obtained. This throughput is insufficient in consideration of the performance required for a variable-length decoding apparatus in the future. When the symbol decoder 1353 can decode in one cycle, an effect obtained upon adopting a parallel arrangement with the high-speed symbol decoder 1532 is lost. Such problem occurs when a table that stores symbol data as a decoding result comprises an asynchronous RAM or hardwired. The recent advance of semiconductor techniques allows to operate at higher clock frequency even if the circuit arrangement remains the same, and a conventional circuit which processes in two cycles can now process in one cycle.
As in prior art 2 , the throughput varies depending on the hit ratio of the 2-successive code word decoder 1402 , and the performance of a maximum of two code words per decoding sequence can be obtained. However, this technique can be implemented in Huffman coding used in MPEG, but cannot be applied to JPEG. This is because variable-length encoded data in JPEG is made up of a Huffman code word and additional bit. For this reason, the 2-successive code word decoder 1402 cannot decode if it simply compares two successive code words with input encoded data, and must consider an additional bit corresponding to a head code word to be decoded by the 1-code word decoder 1403 .
SUMMARY OF THE INVENTION
It is an object of the present invention to implement a variable-length decoding apparatus that can hardly achieve high-speed operations as a pipeline process consisting of three stages by synchronous design using a synchronous RAM. It is another object of the present invention to allow two different decoders to share an additional bit processing circuit and decoded data storage means, and to improve the throughput while minimizing an increase in circuit scale.
In order to achieve the above object, a variable-length decoding apparatus of the present invention comprises the following arrangement.
That is, a variable-length decoding apparatus for decoding encoded data, comprises:
shift means for shifting out a code word and an additional bit corresponding to the code word of input encoded data for each cycle;
a symbol memory for storing decoded data corresponding to a plurality of N code words contained in the input encoded data;
first decode processing means for generating an address of the symbol memory, a code length, and an additional bit length for each of Nt code words fewer than the N code words of the code words input from the shift means;
second decode processing means for generating a code length and an address of the symbol memory for each of the N code words;
address select means for selecting one of the two addresses of the symbol memory input from the first and second decode processing means;
first additional bit processing means for shifting bits of the output from the shift means to the left by the code length input from one of the first and second decode processing means;
second additional bit processing means for shifting bits of the output from the first additional bit processing means to the right by an amount corresponding to symbol data output from the symbol memory; and
operation control means for outputting a shift amount to the shift means.
It is still another object of the present invention to provide a decoding apparatus and method, which can be applied to decoding of JPEG and MPEG encoded data, and can obtain a high throughput.
In order to achieve the above object, for example, one decoding apparatus of the present invention comprises the following arrangement.
That is, a decoding apparatus for decoding variable-length encoded data, and outputting symbol data, comprises:
first shift-out means for shifting out a code word of input encoded data in accordance with shift amount select means, and outputting a head code word and subsequent encoded data;
first decode means for decoding the head code word output from the first shift-out means, and generating first symbol data and a bit length N (N is an integer) of the code word;
second shift-out means for further shifting the head code word and subsequent encoded data output from the first shift-out means on the basis of the bit length N output from the first decode means, and outputting a subsequent first code word; and
second decode means for, when the subsequent first code word output from the second shift-out means belongs to one of a code word group obtained by selecting in advance some of all code words which form the encoded data, generating second symbol data as a decoding result and a bit length M (M is an integer) of the code word,
wherein the shift amount select means determines, as a shift amount of the first shift-out means, a shift amount by selecting a bit length N+M obtained by adding the bit lengths N and M when the second decode means generates the second symbol data, and by selecting the bit length N in other cases.
In the above arrangement, a maximum of two symbol data can be output in one cycle, and the throughput can be remarkably improved compared to the prior art.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a variable-length decoding apparatus according to an embodiment of the present invention;
FIG. 2 is a block diagram showing the internal arrangement of a decode processor 1 ( 103 ) in FIG. 1 in the embodiment of the present invention;
FIG. 3 is a timing chart of the embodiment of the present invention;
FIG. 4 shows the format of encoded data;
FIG. 5 is a block diagram showing the internal arrangement of a decode processor 2 in FIG. 1 in the embodiment of the present invention;
FIG. 6 is a flow chart showing the flow of the process in the decode processor 1 in the embodiment of the present invention;
FIG. 7 is a flow chart showing the flow of the process in the decode processor 2 in the embodiment of the present invention;
FIG. 8 is a flow chart showing the flow of the process in an additional bit processor 1 in the embodiment of the present invention;
FIG. 9 is a table comparing the decode processors 1 ( 103 ) and 2 ( 104 );
FIG. 10 is a block diagram of a decoding apparatus according to the second embodiment of the present invention;
FIG. 11 is a block diagram of a conventional decoding apparatus;
FIG. 12 is a block diagram of a conventional decoding apparatus;
FIG. 13 is a block diagram of a conventional decoding apparatus;
FIG. 14 shows an example of encoded data input to a decoding apparatus of the second embodiment;
FIG. 15 is a table showing the relationship between symbols and code words to be decoded by a specific symbol generate decoder 1103 and all-symbol generate decoder 1104 ;
FIG. 16 is a table showing the states of respective data for respective cycles in the second embodiment;
FIG. 17 is a block diagram of a decoding apparatus according to the third embodiment of the present invention;
FIG. 18 is a timing chart showing the sequence of a variable-length decoding apparatus in the third embodiment, and correspondence with three code words registered in a dynamic code word table 1303 ;
FIG. 19 is a block diagram showing the internal arrangement of a specific symbol address generator 1304 in FIG. 17;
FIG. 20 is a block diagram showing the internal arrangement of an additional bit processor 1302 in FIG. 17;
FIG. 21 is a block diagram of a decoding apparatus according to the fourth embodiment of the present invention;
FIG. 22 shows a zigzag scan of DCT coefficients;
FIG. 23 shows a combination of RRRR/SSSS in the fourth embodiment;
FIG. 24 is a block diagram of a decoding apparatus according to the fifth embodiment of the present invention;
FIG. 25 is a table showing the relationship between a mask pattern and SSSS stored in a mask pattern table in the third and sixth embodiments;
FIG. 26 is a block diagram of a decoding apparatus according to the sixth embodiment of the present invention;
FIG. 27 is a block diagram showing the arrangement of a shift-out unit 1201 in FIG. 26;
FIG. 28 is a block diagram showing the internal arrangement of a RUN 0 /EOB address generator 2102 in FIG. 26;
FIG. 29 is a block diagram showing the internal arrangement of-an all-symbol address generator 2103 in FIG. 26;
FIG. 30 is a block diagram showing the internal arrangement of an additional bit processor 2108 in FIG. 26; and
FIG. 31 is a timing chart showing, as a sequence, an operation example of the variable-length decoding apparatus of the sixth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described in detail hereinafter.
FIG. 1 shows an embodiment of a variable-length decoding apparatus using the present invention. A shift means or unit 101 shifts out each code word of variable-length encoded data for each cycle using a left bit shift processing circuit. Since the shift unit 101 uses a flip-flop, it latches output data of the left bit shift processing circuit for each cycle. This process is defined as stage 1 of a pipeline process.
The process of stage 2 will be described in detail below. FIG. 2 shows the internal arrangement of a decode processor 1 ( 103 ). FIG. 6 is a flow chart showing the flow of the process in the decode processor 1 . A table storage means comprises a code word array 402 which comprises a flip-flop, and stores Nt (N>Nt>0) of N (N>1) code words present in advance in a variable-length code table, a code length & code length +additional bit length array 404 for storing two different types of numbers of bits, i.e., Nt code lengths corresponding to the code word array 402 , and Nt code lengths+additional bit lengths M (M>0), and an address array 403 for storing Nt addresses of a symbol memory 108 . It is checked if code words output from the code word array 402 in the table storage means match the outputs from the shift unit 101 in Nt comparators of a comparator group 408 . In this checking, since the code lengths of code words present in the code word array 402 are known, each of the Nt comparators compares for only a code length to be compared. That is, each comparator in the comparator group 408 compares for the number of bits according to a code length to be compared, which ranges from 1 bit (minimum) to a maximum code length.
The output signals from these Nt comparators in the comparator group 408 are input to a decoder 401 , which generates a select signal for selecting one of Nt data of the address array 403 and the code length & code length+additional bit length array 404 . The outputs from an MUX 406 are two different signals indicating the code length and the M bits. The signal indicating the M bits is output to an operation controller 105 in FIG. 1, and the code length is output to an additional bit processor 1 ( 102 ). Output data from an MUX 405 is used as the address of the symbol memory 108 .
On the other hand, the arrangement of a decode processor 2 ( 104 ) is as shown in FIG. 5 . The flow of the process in the decode processor 2 is as shown in the flow chart of FIG. 7 . In this processor, maximum or minimum code words for respective code lengths are pre-stored in a code word array 502 , and the code length of input encoded data (S 701 ) is obtained using comparators 503 and a priority encoder 504 (S 702 ). If the code word array 502 stores maximum code words, the priority of the priority encoder becomes higher in the order from larger code length; when the array 502 stores minimum code words, the priority becomes lower in the order from smaller code length. Since the number of comparators corresponds the number (N 1 ) of code lengths, the gate scale is constant. An initial data array 505 pre-stores initial data corresponding to maximum or minimum code words for respective code lengths on the code word array 502 . Access to the initial data array is made using a decoder 501 on the basis of the obtained code length (S 703 ). The address of the symbol memory 108 is obtained by adding initial data corresponding to the obtained code length and the input encoded data by an arithmetic device 506 (S 704 ).
For example, when initial data of minimum code words are stored, the address of the symbol memory is obtained by:
ADDR=VLCin−VLCmin+ADDRbase=VLCin+(ADDRbase−VLCmin)
where ADDR is the address of the symbol memory, VLCin is lower 8 bits of a code word which is currently shifted out by the shift unit 101 , VLCmin is the minimum code word of an identical code length, and ADDRbase is the address of the minimum code word in the symbol memory. Lower 8 bits obtained by computing (ADDRbase−VLCmin) of the right-handed side correspond to initial data. If the code word, which is currently shifted out by the shift unit 101 , is less than 8 bits, “0” or “0”s is or are padded in the vacant upper bit or bits.
FIG. 9 compares the decode processors 1 ( 103 ) and 2 ( 104 ). In a cycle in which encoded data can be decoded by the decode processor 1 , since the variable code length and additional bits can be shifted out in one cycle with respect to the shift unit 101 , successive encoded data can be decoded in the next cycle.
On the other hand, when decoding is made by the decode processor 2 , the obtained code length is stored in the first cycle, and a shift-out process is done by adding the code length and an additional bit length obtained from the symbol memory 108 in the next cycle. Hence, two cycles are required until the decoding process of encoded data starts.
An address selector 106 selects the output from the decode processor 1 ( 103 ) in a cycle in which at least one match is detected by the Nt comparators in the decode processor 1 ( 103 ), and selects the output from the decode processor 2 ( 104 ) in other cycles. On the other hand, the additional bit processor 1 ( 102 ) receives the code lengths from the decode processors 1 ( 103 ) and 2 ( 104 ). FIG. 8 is a flow chart of the process in the additional bit processor 1 .
In the process in the additional bit processor 1 , in a cycle in which at least one match is detected by the Nt comparators in the decode processor 1 ( 103 ), the code length input from the decode processor 1 ( 103 ) is selected, and a left bit shift operation is done (S 802 , S 804 , S 805 ). In other cases, the code length input from the decode processor 2 is selected, and a bit shift operation is made (S 803 ). In this case, the result of the bit shift process is stored in a flip-flop for each cycle (S 806 ). The aforementioned operations are made in stage 2 of the pipeline process.
The process executed in stage 3 of the pipeline process will be explained below. In stage 3 , the output from the symbol memory 108 and the output from the additional bit processor 1 ( 102 ) are used. An additional bit processor 2 ( 107 ) performs a right bit shift operation of input data from the flip-flop of the additional bit processor 1 ( 102 ) using an additional bit length as a part of symbol data output from the symbol memory 108 as a shift amount.
The result of this shift operation is used as output additional bit data of this decoding apparatus. Symbol data output from the symbol memory 108 is directly used as output symbol data of this decoding apparatus. If the address output from the decode processor 2 ( 104 ) was used in the previous cycle, the operation controller 105 adds the code length stored in the previous cycle, and an additional bit length as a part of symbol data output from the symbol memory 108 , and outputs the sum to the shift unit 101 .
FIG. 3 is a timing chart of the variable-length decoding apparatus of this embodiment, and FIG. 4 shows an example of encoded data input to this decoding apparatus.
In cycle 1 , variable-length code 1 is shifted out by the shift unit 101 as it is shifted up to the MSB side. The decode processors 1 ( 103 ) and 2 ( 104 ) receive identical encoded data. Variable-length code 1 is not present in the table storage means of the decode processor 1 ( 103 ), and all the outputs from the comparator group 408 are false.
On the other hand, the decode processor 2 ( 104 ) calculates and outputs the code length of variable-length code 1 , and the address of the symbol memory 108 . The additional bit processor 1 ( 102 ) executes a left bit shift process of output data from the shift unit 101 on the basis of the code length input from the decode processor 2 ( 104 ), and stores the result in the flip-flop. The operation controller 105 stores the code length input from the decode processor 2 ( 104 ) in the flip-flop.
In cycle 2 , the symbol memory 108 outputs symbol data corresponding to variable-length code 1 as decoded data. The additional bit processor 2 executes a right bit shift process of data input from the additional bit processor 1 ( 102 ) using a part of symbol data as a shift amount, and outputs the result as additional bit data. The operation controller 105 also receives an additional bit length as a part of symbol data, adds the code length stored in the previous cycle and the additional bit length, and outputs the sum as a shift amount to the shift unit 101 .
In cycles 3 and 4 , the same operations as in cycles 1 and 2 are done, respectively. In cycle 5 , variable-length code 3 , which is currently shifted out by the shift unit 101 , matches one of code words pre-stored in the flip-flop in the decode processor 1 ( 103 ). The additional bit processor 1 ( 102 ) executes a left bit shift process based on the code length input from the decode processor 1 ( 103 ). The operation controller 105 outputs the code length+additional bit length input from the decode processor 1 ( 103 ) to the shift unit 101 as a shift amount.
That is, in the next cycle 6 , additional bits have already been shifted out, so the next variable-length code 5 is shifted out from the shift unit 101 this time. In this cycle as well, the decode processor 1 ( 103 ) detects a match of a Huffman code word, and the additional bit processor 1 ( 102 ) and operation controller 105 execute the same operations as in cycle 5 . On the other hand, in stage 3 of the pipeline process, the symbol memory 108 outputs symbol data corresponding to variable-length code 3 as decoded data, and the additional bit processor 2 ( 107 ) executes a right bit shift process using a part of symbol data as a shift amount, and outputs the result of the bit shift process as additional bit data.
The same processes are done in cycles 7 to 9 . In cycle 10 , the decode processor 1 ( 103 ) does not detect any match with code words, and the code length of the decode processor 2 ( 104 ) and the address of the symbol memory are enabled in stage 2 of the pipeline process. In stage 3 of the pipeline process, symbol data corresponding to variable-length code 7 and additional bits are output.
As described above, according to this embodiment, a variable-length decoding apparatus which can hardly attain high-speed operations can be implemented as a pipeline process consisting of three stages by synchronous design using a synchronous RAM. The additional bit processing circuit and decoded data storage means can be shared by two different types of decoders and, hence, the throughput can be improved while minimizing an increase in circuit scale.
Second Embodiment
FIG. 10 is a block diagram of a variable-length decoding apparatus which is applied to JPEG in the second embodiment of the present invention.
A shift-out unit 1101 receives encoded data made up of variable-length code words and additional bits. The input/output data widths of encoded data of the shift-out unit 1101 have identical numbers of bits, and are equal to or larger than a maximum code word length +maximum additional bit length. The shift-out unit 1101 mainly combines input encoded data and that present in the shift-out unit 1101 in the current cycle, and shifts out the combined data in accordance with a shift amount input from an operation controller 1105 .
Encoded data output from the shift-out unit 1101 is parallelly input to an all-symbol generate decoder 1104 and left-shift unit 1102 . Note that the left-shift unit 1102 comprises a shift circuit and the like. In this circuit, since the input bitstream is output from its MSB side, “left shift” is used herein.
The all-symbol generate decoder 1104 decodes symbol data (RRRR/SSSS) for all code words which form encoded data, and outputs the number N of bits (integer) obtained by adding the code length and additional bit length (SSSS).
On the other hand, the next code word, which follows the code word corresponding to symbol data decoded by the all-symbol generate decoder 1104 and additional bits, is shifted out, since the output data from the left-shift unit 1102 has undergone the left-shift process by N bits input from the all-symbol generate decoder 1104 .
A specific symbol generate decoder 1103 checks if one of code words, which are registered in advance, matches encoded data output from the left-shift unit 1102 . If the two data match, the decoder 1103 asserts a hit signal (=“1”), and outputs the corresponding symbol data and M (integer) bits obtained by adding its code word length and additional bit length. For example, a plurality of symbols in descending order of frequency of generation are decoded by the specific symbol generate decoder 1103 .
The operation controller 1105 controls (determines) the shift amount of the shift-out unit 1101 . The shift amount is N+M bits if a hit signal is asserted, or is N bits if a miss has occurred.
In this way, the all-symbol generate decoder 1104 always decodes and outputs symbol data independently of hits in the specific symbol generate decoder 1103 , and if a hit has occurred, two symbol data are output at the same time.
<Description of Operation>
The operation of the variable-length decoding apparatus in the second embodiment will be explained below. For the sake of simplicity, encoded data input to the variable-length decoding apparatus consists of eight different symbol data. In this case, the relationship between symbol data and code words decoded by the specific symbol generate decoder 1103 and all-symbol generate decoder 1104 is as shown in FIG. 15 . The all-symbol generate decoder 1104 decodes all of eight different symbol data, and the specific symbol generate decoder 1103 decodes top three different symbol data with higher frequency of generation.
FIG. 14 shows a bit pattern of the input encoded data. In FIG. 14, A indicates additional bits, which form an arbitrary bit pattern of 0s or 1s. Also, the input/output encoded data width of the shift-out unit 1101 is 16 bits.
FIG. 16 shows the states of respective data in respective cycles, and the data states will be explained below.
In cycle 0 , the shift-out unit 1101 shifts out code word “00” (which is 2-bit data as can be seen from FIG. 15 ). This code word “00” is decoded by the all-symbol generate decoder 1104 , and 0 / 1 (RRRR/SSSS) is output as symbol data. Also, N=3 bits as the sum of 2 bits (code word length) and 1 bit (additional bit length) is output to the left-shift unit 1102 . The left-shift unit 1102 left-shifts encoded data input from the shift-out unit 1101 by N=3 bits, and outputs the shifted data to the specific symbol generate decoder. “Zeros” in ( ) in FIG. 16 are padded by the left-shift unit 1101 . The specific symbol generate decoder 1103 checks if the encoded data input from the left-shift unit 1102 matches one of three code words “00”, “01”, and “100” which are registered in advance. In the output from the left-shift unit 1102 in cycle 0 , since code word “01” is shifted out, the specific symbol generate decoder 1103 asserts a hit signal, and outputs symbol data 0 / 2 and M=4 bits to the operation controller 1105 .
On the other hand, the operation controller generates a shift amount for the shift-out unit 1101 under the following condition. Note that L bits represent the data size and S bits represent the shift amount in the shift-out unit 1101 in the current cycle.
If hit occurs:
IF (L>N) THEN
IF ((L−N)>M) THEN
S=N+M
ELSE
S=N
END IF
ELSE
S=0
END IF
If miss occurs:
IF (L>N) THEN
S=N
ELSE
S=0
END IF
In cycle 0 , since the code word hits the specific symbol generate decoder 1103 and (L−N)>M, N+M=7 bits is output as the shift amount. Also, both a symbol data 2 enable signal indicating that symbol data output from the specific symbol generate decoder 1103 is enabled, and a symbol data 1 enable signal indicating that symbol data output from the all-symbol generate decoder 1104 is enabled are asserted (=“1”).
In cycle 1 , the shift-out unit 1101 shifts out code word “1011”, and the all-symbol generate decoder 1104 outputs symbol data 0 / 4 and N=8 bits. In the left-shift unit 1102 , although code word “11011” is shifted out, since this code word is not registered in the specific symbol generate decoder 1103 , a miss occurs, and a hit signal is deasserted (=“0”). Hence, the shift amount S=8 bits is output to deassert the symbol data 2 enable signal and assert the symbol data 1 enable signal. The same operations are repeated for cycles 2 and 3 .
In cycle 4 , the data size of only 8 bits is present in the shift-out unit 1101 . The all-symbol generate decoder 1104 decodes shifted-out code word “00” and outputs symbol data 0 / 1 and N=3 bits. In the output of the left-shift unit 1102 , code word “100” is shifted out, and the specific symbol generate decoder 1103 generates symbol data 0 / 3 . However, since category SSSS=3, the additional bit length is 3 bits, and M=6 bits is output. However, the number of effective bits input from the left-shift unit 1102 to the specific symbol generate decoder 1103 in the current cycle is L−N=8−3=5 bits, which are smaller than M bits. Therefore, although a hit has occurred upon a code word, the shift-out unit 1101 does not execute a shift-out process, and a symbol data 2 enable instruction signal is deasserted. Hence, in cycle 4 , the variable-length decoding apparatus outputs only one symbol data.
In cycle 5 , code word “100”, decoding of which was tried by the specific symbol generate decoder 1103 in the previous cycle, is decoded again by the all-symbol generate decoder 1104 . Also, the specific symbol generate decoder 1103 decodes code word “00”, thus outputting two symbol data.
With the aforementioned arrangement and operation, the throughput of the variable-length decoding apparatus can be improved, although such improvement is hardly attained in the prior art. Furthermore, even in variable-length encoded data which is made up of Huffman code words and additional bits used in JPEG, two symbol data can be output at the same time in a single decoding sequence.
Third Embodiment
FIG. 17 is a block diagram of a variable-length decoding apparatus according to the third embodiment of the present invention.
In the variable-length decoding apparatus in the third embodiment, symbol data as decoding results are stored in a single symbol memory 1311 as a synchronous RAM. Address generation of that memory is implemented by two means, i.e., a specific symbol address generator 1304 and all-symbol address generator 1305 . The specific symbol address generator 1304 obtains the number of bits for a code word length+additional bit length for some limited symbols of all symbols present in encoded data, and the all-symbol address generator 1305 obtains a code word length for each of all symbols. The latency required for the variable-length decoding apparatus to decode one symbol data is two cycles. When the shift amount shifted out by a shift-out unit 1301 hits in the specific symbol address generator 1304 , since the shift-out unit 1301 shifts out a code word and additional bits in one cycle, the next symbol can be decoded in the next cycle, and a throughput of maximum of 1 symbol/cycle can be obtained. That is, how to select symbols to be decoded by the specific symbol address generator 1304 largely influences the throughput. Hence, in the third embodiment, the frequency of generation of symbol data output from the symbol memory 1311 is measured, and a plurality of symbols in descending order of frequency of generation are decoded by the specific symbol address generator 1304 . Furthermore, these symbols to be selected are dynamically replaced in turn.
<Detailed Description of Operation>
The operation of the variable-length decoding apparatus of the third embodiment will be described below. For the sake of simplicity, assume that there are 26 different code words A to Z in ascending order of absolute value as variable-length codes.
The number of symbols to be decoded by the specific symbol address generator 1304 is three.
FIG. 18 is a timing chart of the variable-length decoding apparatus and also shows three code words registered in a dynamic code word table 1303 , and a sequence. If symbols have the same frequency of generation, a symbol corresponding to a code word having a smaller absolute value is preferentially selected.
In cycle 0 , the shift-out unit 1301 shifts out code word A. Since this cycle is the first cycle of the decoding process, no code words are registered in the dynamic code word table. Hence, a miss has occurred in the specific symbol address generator 1304 , and the address generated by the all-symbol address generator 1305 is selected by a selector 1310 as the address of the symbol memory 1311 .
The internal arrangement of the specific symbol address generator 1304 is as shown in FIG. 19 . The specific symbol address generator 1304 operates as follows in this cycle. That is, a comparator group 1501 determines based on three different code words and code lengths input from the dynamic code word table 1301 that the input encoded data does not match any of these code words, and the hit signal remains deasserted (=“0”).
On the other hand, the all-symbol address generator 1305 obtains a code length by comparing with a maximum code word as a maximum absolute value present in each code length as in the conventional method. This maximum code word is input from a static maximum code word table 1306 . In this case, a setup of maximum code words in the static maximum code word table 1306 must be completed before the beginning of decoding of the variable-length decoding apparatus, and table entry values remain unchanged during decoding like the dynamic code word table 1303 .
In cycle 1 , the symbol memory 1311 outputs symbol data corresponding to the address generated by the all-symbol address generator 1305 in the previous cycle, and this data is used as the output of this variable-length decoding apparatus. Since the shift-out unit 1301 shifted out encoded data by the code word length in the previous cycle, the additional bits of this symbol data have already been shifted out by the shift-out unit 1301 .
Furthermore, an additional bit length can be obtained from symbol data by a known method, and is output after a right shift process. The internal arrangement of an additional bit processor 1302 is as shown in FIG. 20 (the contents of a mask pattern table 1605 in FIG. 20 are as shown in FIG. 25 ). If a hit has occurred in the specific symbol address generator 1304 , since the code word+additional bits are shifted out from the shift-out unit 1301 in one cycle, a flip-flop 1602 temporarily latches data which has been shifted to the left by the code word length, and a right shift process is executed in the next cycle.
A static code word table 1309 pre-stores code words, code lengths, code lengths+additional bit lengths, and symbol memory addresses of all symbols or a plurality of symbols with higher frequency of generation. In the static code word table 1309 , a setup of entries must be completed before the beginning of decoding of the variable-length decoding apparatus, like in the static maximum code word table 1306 , and entry values remain unchanged.
A generation frequency histogram 1308 counts the frequency of generation of symbol data present in the static code word table 1309 in accordance with the output from the symbol memory 1311 to select top three symbol data with higher frequency of generation, which are supplied to the dynamic code word table 1303 .
When the operations in cycles 0 and 1 are repeated up to cycle 5 , three different data, i.e., code words A, B, and C are selected in the dynamic code word table 1303 .
In cycle 6 , the shift-out unit 1301 shifts out code word C. Since code word C is present in the dynamic code word table 1303 , a hit is determined in the specific symbol address generator 1304 . Hence, the shift-out unit 1301 simultaneously shifts out code word C and additional bits during cycle 6 , and shifts out the next code word in the next cycle 7 .
As for cycle 7 , a symbol with high frequency of generation can always be processed by the specific symbol address generator 1304 by counting the frequency of generation based on the output from the symbol memory 1311 , thus improving the throughput.
In the third embodiment, only three different symbols are selected in the dynamic code word table 1303 , but all symbols in maximum may be selected by a trade-off with the gate scale. Also, the types of code words are limited to code words A to Z for the sake of simplicity, but this embodiment can be applied to any Huffman codes.
Fourth Embodiment
The fourth embodiment will be described in detail below. FIG. 21 is a block diagram of a variable-length decoding apparatus in the fourth embodiment.
In general, in JPEG, an 8×8 block that has undergone a DCT arithmetic process is quantized, and the quantization coefficients undergo an entropy coding process. FIG. 22 shows the state of zigzag transformation (zigzag scan) of a DCT block. The order DCT coefficients are input to a variable-length encoding apparatus is that after zigzag transformation. As for DC components, a one-dimensional entropy coding process is done to have a difference value from the previous DCT block as SSSS by a method called DCPM. After that, 63 successive DCT coefficients undergo a two-dimensional entropy coding process of two-dimensional RRRR/SSSS. FIG. 23 shows combinations of RRRR/SSSS. In case of around 1/10 as a normal compression ratio in an image compressed by JPEG, combinations of RRRR/SSSS generated are offset depending on the positions (scan count values) of DCT coefficients in the zigzag order.
In the fourth embodiment, a specific symbol address generator 1704 selects a symbol (RRRR/SSSS) to be decoded in accordance with a scan count value in consideration of the above phenomenon, thereby improving the throughput.
<Detailed Description of Operation>
The operation of the decoding process is substantially the same as in the third embodiment, except for entry of code words to a dynamic code word table 1703 . In the fourth embodiment, a plurality of tables that select symbols with high frequency of generation corresponding to the scan count values are prepared before the beginning of the decoding process. For example, in the fourth embodiment, three different tables are prepared in advance in correspondence with an initial scan (scan count values 1 to 23 ), middle scan ( 24 to 40 ), and last scan ( 41 to 63 ). The number of symbol entries in each table is a trade-off with the gate scale. If the system of the third embodiment is used, three different symbols are set in each table. In this way, as the scan count value is counted up, the specific symbol address generator 1704 selects a symbol to be processed at high speed, thus improving the hit rate and the throughput.
Fifth Embodiment
The fifth embodiment will be described below.
FIG. 24 is a block diagram showing an apparatus in the fifth embodiment.
<Outline of Arrangement>
In general, in encoded data with low compression ratio, the frequency of generation of symbols with a small runlength value is high. Conversely, in encoded data with high compression ratio, the frequency of generation of symbols with a large runlength value is high.
Hence, in the fifth embodiment, an optimal one of a plurality of tables, which are prepared in advance, is selected in accordance with the compression ratio of encoded data to be decoded, so as to select a symbol (RRRR/SSSS) to be decoded by a specific symbol address generator 1804 , thereby improving the throughput.
<Detailed Description of Operation>
The arrangement and operation of this embodiment are substantially the same as those in the third embodiment except for a supply unit of code words, code word lengths, code word lengths+additional bit lengths, and symbol memory addresses to the specific symbol address generator 1804 .
Before the beginning of decoding, the compression ratio of encoded data to be decoded is set from an apparatus outside the variable-length decoding apparatus. A selector 1808 selects one of tables, which are prepared in advance, in accordance with that compression ratio, and inputs the selected table to the specific symbol address generator 1804 . In this embodiment, the selected table remains unchanged during decoding.
As described above, according to the third to fifth embodiments, by adaptively selecting symbols which are to undergo a high-speed decoding process, the throughput can be improved compared to the prior art.
Sixth Embodiment
The sixth embodiment will be described below.
<Apparatus Arrangement>
FIG. 26 is a block diagram of a decoding apparatus of the sixth embodiment.
The arrangement of the decoding apparatus will be explained first. Encoded data input to this decoding apparatus is input to a shift-out unit 2101 . FIG. 27 shows the arrangement of the shift-out unit 2101 . The input encoded data is shifted by a right-shift unit 2301 to be coupled to the final effective bit of encoded data output from a left-shift unit 2302 . On the other hand, a flip-flop 2304 outputs the shifted-out encoded data to a RUN 0 /EOB address generator 2101 and all-symbol address generator 2103 , and supplies it to the left-shift unit 2302 . The left-shift unit 2302 shits bits corresponding to the shift amount input from an operation controller 2107 to the left.
On the other hand, an input apparatus to this variable-length decoding apparatus inputs encoded data to the variable-length decoding apparatus if the data size to be input to the variable-length decoding apparatus in the current cycle is equal to or smaller than a value obtained by subtracting the data size from the data bus width of encoded data.
FIG. 28 shows the internal arrangement of the RUN 0 /EOB address generator 2102 . When the runlength is “0” and a code word corresponding to an EOB symbol is shifted out, the RUN 0 /EOB address generator 2102 outputs an address of a symbol memory and a shift amount. These data are respectively stored in a code word length+additional bit length table 2404 and symbol memory address table 2405 as the code word length+additional bit length corresponding to zero runlength and EOB symbol, and the address of the symbol memory.
Comparators of a comparator group 2401 receive code words corresponding to zero runlength and EOB, and check if they match. If at least one of the comparators of the comparator group 2401 matches a code word, data corresponding to that code word are selected from two tables, i.e., the code word length+additional bit length table 2404 and symbol memory address table 2405 and are output. At the same time, a hit signal is asserted.
FIG. 29 shows the internal arrangement of the all-symbol address generator 2103 . The all-symbol address generator 2103 outputs at least a code word and an address of a symbol memory 2105 corresponding to a symbol which is not registered in the RUN 0 /EOB address generator 2102 . An implementation means of the all-symbol address generator 2103 uses known prior art. Encoded data is compared with maximum code words for respective code word lengths in a comparator group 2501 . The outputs from comparators are supplied to a priority encoder 2502 which is given higher priority in ascending order of code length.
In this case, a minimum one of code word lengths from the comparators which determined that the encoded data value is equal to or smaller than the maximum code word length is used as a code word length of the currently shifted-out code word. The address of the symbol memory assumes a value obtained by subtracting the difference from the maximum code word of the currently shifted-out code word from the value of a corresponding code length selected from a symbol memory address table 2506 that stores the addresses of maximum code words of respective code word lengths on the symbol memory.
FIG. 30 shows the internal arrangement of an additional bit processor 2108 . The processing sequence of additional bits varies depending on whether or not a hit has occurred in the RUN 0 /EOB address generator 2102 . If a hit has occurred, encoded data is shifted to the left by a code length, and is then delayed by one clock by a flip-flop 2602 . A hit signal is delayed by one cycle by a flip-flop 2603 to be used as a select signal of a selector 2604 , and if a hit has occurred, the output from the flip-flop 2602 is selected. The output from the selector 2604 is logically ANDed with a bit pattern selected from a mask pattern table 2605 in accordance with symbol SSSS. The relationship between the mask pattern and SSSS is the same as that shown in FIG. 25 . The AND signal undergoes a right shift process for the number of bits obtained by subtracting the value of symbol SSSS from 11, and the shift process result is output as additional bits.
The operation of the operation controller 2107 will be described below.
The operation controller 2107 compares the data size present in the shift-out unit 2101 in the current cycle with the code word length+additional bit length input from the RUN 0 /EOB address generator 2102 if a hit has occurred, or with the code word length input from the all-symbol address generator 2103 if a miss has occurred. If the data size is smaller than the input value, a selector 2106 selects zero shift amount until a cycle in which the data size becomes equal to or larger than the input value. The shift amount is the code word length+additional bit length if a hit has occurred in the RUN 0 /EOB address generator 2102 , or is the code word length in the first cycle and the additional bit length in the next cycle if a miss has occurred. If two code words have successively been missed, a RUN 1 gambling execution process for outputting information indicating a runlength=“1” to the subsequent blocks is executed in the first cycle. A miss that has occurred in the RUN 0 /EOB address generator 2102 means a runlength=“1” or more. In this manner, the subsequent blocks of the variable-length decoding apparatus can execute a variable-length decoding process without lowering the throughput even when the all-symbol address generator 2103 that requires two processing cycles executes processes.
<Description of Operation>
FIG. 31 is a timing chart showing an operation example of the variable-length decoding apparatus of the sixth embodiment.
Cycle 0 indicates that encoded data output from the shift-out unit 2101 is parallelly processed by the RUN 0 /EOB address generator 2102 and all-symbol address generator 2103 and, consequently, a miss has occurred in the RUN 0 /EOB address generator 2102 . Hence, the selector 2104 selects the symbol memory address input from the all-symbol address generator 2103 , and the selector 2106 selects a code word length as a shift amount in the operation controller. In case of a processing cycle for DC components, even when a miss has occurred in the RUN 0 /EOB address generator 2102 , no RUN 1 gambling execution is made. In the sixth embodiment, a synchronous RAM is assumed as the symbol memory 2105 .
In cycle 1 , the shift-out unit 2101 shifts out additional bits corresponding to code word 0 .
The additional bit lengths are the value of symbol SSSS output from the symbol memory 2105 . The additional bit generator 2108 generates additional bits on the basis of this symbol SSSS, and outputs these its to subsequent blocks together with symbol data output from the symbol memory 2105 . At this time, the operation controller 2107 asserts an effective data instruction signal (=“1”) to inform the subsequent blocks that the variable-length decoding apparatus outputs effective symbol and additional bit data in the current cycle 1 . Also, the operation controller 2107 selects the additional bit length as a shift amount.
In cycle 2 , the shift-out unit 2101 shifts out code word 1 of AC components. Since this shifted-out code word 1 matches a code word registered in advance in a RUN 0 /EOB code word table 2403 in the RUN 0 /EOB address generator 2102 , a hit signal is asserted (=“1”). Hence, as the address of the symbol memory, the selector 2104 selects the output of the RUN 0 /EOB address generator 2102 , and the selector 2106 selects the code word length+additional bit length as a shift amount.
In the next cycle 3 , the symbol memory 2105 outputs symbol data corresponding to code word 1 . In this state, the shift-out unit 2101 has already shifted out additional bits corresponding to code word 1 . For this reason, the additional bit processor 2108 latches data obtained by shifting out code word 1 to shift out additional bits in the flip-flop 2602 in cycle 2 . In this way, additional bits can be generated based on symbol SSSS output from the symbol memory in cycle 3 .
In cycles 3 , 4 , and 5 , the same operations as in cycles 0 , 1 , and 2 are repeated.
In cycle 6 , code word 4 shifted out by the shift-out unit 2101 is not registered in the RUN 0 /EOB code word table 2403 in the RUN 0 /EOB address generator 2102 , and a miss occurs. Since a similar miss occurred in cycle 4 , two code words successively shifted out by the shift-out unit 2101 are missed. In this case, symbol data which is effective in terms of pipeline operations in the arrangement of the variable-length decoding apparatus cannot be output, and a bubble cycle is generated. Hence, to avoid a decrease in throughput, a signal indicating RUN 1 gambling execution as information indicating a runlength=“1” is asserted (=“1”) in cycle 6 .
In the subsequent cycle 7 , symbol data and additional bits corresponding to code word 4 are output. In cycle 8 as well, since a miss has occurred in the RUN 0 /EOB address generator 2102 , RUN 1 gambling execution is made as in cycle 6 . In the next cycle 9 , symbol data and additional bits corresponding to code word 5 are output.
As described above, according to the sixth embodiment, the RUN 0 /EOB address generator 2102 is arranged parallel to the all-symbol address generator 2103 that uses prior art, so as to improve the throughput compared to the prior art while suppressing an increase in the number of gates. In order to allow operations at high-speed clock operation frequency, the identical processing latency of the RUN 0 /EOB address generator 2102 is set equal to the all-symbol address generator 2103 to implement a pipeline process. In order to prevent a bubble cycle generated in the pipeline process, RUN 1 gambling execution is made to further improve the throughput.
When the all-symbol address generator 2103 executes decoding corresponding to RUN 1 symbol data, RUN 1 gambling execution works very effectively in the subsequent block for converting symbol data into orthogonal coefficients, thus further improving the throughput. This is because RUN 1 symbol data are obtained by encoding two orthogonal coefficients, i.e., an insignificant coefficient (orthogonal coefficient value=0) and nonzero significant coefficient and, in such case, a bubble cycle can be prevented in the subsequent blocks.
In the above embodiments, a hardware decoding apparatus has been explained. However, it is easy for those who are skilled in the art that a memory (table) in the apparatus arrangement of each embodiment comprises a RAM, and other processors can be implemented by a program. Therefore, the present invention can be applied not only to the decoding apparatus but also to a decoding method, a computer program, and a computer readable storage medium that stores the program (a storage medium which is used to install a program in a computer; for example, a floppy disk, CD-ROM, or the like).
As described above, the present invention can be applied to decoding of both JPEG and MPEG encoded data, and can obtain a high throughput.
As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.
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This invention implements a variable-length code pipeline decoding process as hardware by providing additional bit processing means, reducing the load on external control, and clarifying encoded data shift means. For this purpose, in order to determine a code length and additional bit length, two different decode processes are executed, the overall process is separated into three stages, i.e., a stage for shifting out a code word of encoded data, a decode processing stage, and a symbol determination & additional bit processing stage, and these stages are executed in a pipeline manner.
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BACKGROUND OF THE INVENTION
The Government has rights in this invention pursuant to Contract No. F29601-89-C-0084, awarded by The Department of the Air Force.
The present invention relates to digital level shifters and more specifically to CMOS low power level shifters. Level shifters are required when data or control signals must pass between digital logic circuits having two different power supply voltages.
Many applications of integrated circuits are requiring lower power supply voltages. While historically it was common to utilize 5 volt supplies, presently there are requirements for 3.3 volt, 2.5 volt and even lower voltage supplies for portions of systems. The reasons for this requirement include lower power consumption and the fact that improved performance is obtained when the voltage swing is limited to a lower value. The lower power supply voltages may be required for only a portion of a system, but the portion of the system having the lower power supply voltage must be able to communicate with other portions of the system having higher power supply voltages. For example, a single application specific integrated circuit (ASIC) may be designed to have both 3.3 volt and a 5 volt power supply zones. Separate power supply zones raise an issue as to power being applied at different times in different zones and how this will affect the operation and power consumption of the logic circuits. For example, a logic stage preceding a level shifter may operate with a 2.5 volt supply voltage while the level shifter and the logic stage following the level shifter may operate with a 5 volt supply voltage. If the 5 volt supply is applied before the 2.5 volt supply, the output(s) of the level shifter may float to intermediate level voltages. These intermediate levels can cause both p-channel and n-channel transistors in the logic stage following the level shifter to be partially on, resulting in DC current in the logic stage and in excessive power consumption. This DC current is referred to as "crow bar" current. This "crow bar" current will continue to flow between the power supply and ground of the following stages until the 2.5 volt power supply is applied. Additional logic stages downstream can also be affected in the same way. A similar situation occurs if both the 2.5 volt and the 5 volt supplies are operating, and then the 2.5 volt supply is turned off but the 5 volt supply remains turned on.
The problem just described is of course not limited to a single ASIC. For example, a core portion of a system may utilize 3.3 volts with the input/output (I/O) having some 3.3 volt integrated circuits (IC's) and some 5 volt IC's. The 3.3 volt supply is referred to as the core voltage, V C , and the 5 volt supply is referred to as the ring voltage, V R . In order for the core to communicate with the 5 volt IC's a translator or level shifter is required to translate the 3.3 volts to the 5 volt ring voltage supply and similar problems of intermediate output values can occur.
In the past the solution to this problem just described as been to require the designer of the system to assure that the power supplies come on at the same time or to simply accept the additional power drain.
Thus a need exists for a digital logic level shifter that does not introduce intermediate values into the circuitry as a result of the presence or absence of power supply voltages.
SUMMARY OF THE INVENTION
The present invention solves these and other needs by providing a logic level shifter for coupling a first logic circuit having a first voltage level power supply to a second logic circuit with the shifter and the second logic circuit having a second voltage level supply and with the second voltage level supply applied at a time when the first level voltage supply is not applied. In the preferred form, the level shifter accepts a first logic signal which can vary from a reference voltage to the first voltage and a second logic signal which is a complement of the first logic signal and can vary from a reference voltage to the first voltage. A first output provides a signal which can vary from the reference voltage to the second voltage and a second signal which is the complement of the first output signal. The logic level shifter includes means for maintaining the first output and the second output at either the reference voltage or the second voltage during times when the first voltage level power supply is not present.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of a logic level shifter in accordance with the principles of the present invention.
FIG. 1 a is a schematic of a portion of FIG. 1 and shows an alternate arrangement.
DETAILED DESCRIPTION
In FIG. 1, a logic level shifter 10 in accordance with the principles of the present invention includes p-channel MOB transistors 12 and 14, and n-channel MOS transistors 16, 18, and 20. Level shifter 10 is powered by a single power supply level V R . The source of p-channel transistor 12 is connected to voltage V R , the source of n-channel transistor 16 is connected to a reference voltage (ground) and the drains of transistors 12 and 16 are connected at point A which is connected to the gate of p-channel transistor 14 and to output 22. The source of p-channel transistor 14 is connected to voltage V R , the source of n-channel transistor 18 is connected to ground and the drains of transistors 14 and 18 are connected at point B which is connected to the gate of p-channel transistor 12 and to output 24. N-channel transistor 20 has its source connected to a reference voltage, (ground), its drain connected to the common drain connection of transistors 16 and 18, and its gate connected to output 22.
In the preferred form shown in FIG. 1, level shifter 10 includes inverter 30 which receives digital signals at 38 from logic circuit 44. Logic circuit 44 operates at a core voltage, V C . Inverter 30 includes p-channel MOS transistor 32 and n-channel MOS transistor 34. The source of p-channel transistor 32 is connected to a first supply voltage designated V C , with the source of n channel transistor 34 connected to a reference voltage (ground). The gates of transistors 32 and 34 have a common connection which forms an input to inverter 30. The drains of transistors 32 and 34 have a common connection to an output 36. In the operation of inverter 30, digital input signals are provided at input 38 which is connected to the gates of transistors 32 and 34. If the voltage level of digital input signal 38 is high corresponding to a "1" logic state, n-channel transistor 34 will be turned on, pulling output 36 to ground which corresponds to a low logic state, thus inverting the input signal at 38. Conversely when the voltage level at 38 is low, n-channel transistor 34 will be turned off and p-channel transistor 32 will be turned on pulling output 36 to the value of V C corresponding to a high or "1" logic state.
The operation of level shifter 10 will be explained by assuming that inverter 30 is operating with a core voltage, V C , of 3 volts and level shifter 10 is operating with a ring voltage, V R , of 5 volts, it is understood that these voltages are only for illustration purposes and other voltages may be used. In the operation of level shifter 10, with a logic level 1 (3 volts) at input 38, n-channel transistor 34 will be turned on and the signal 36, which is the inverse of signal 38, will be low which will turn off n-channel transistor 18. The logic level 1 signal at input 38 will turn on n-channel transistor 16 which will cause point A to and output 22 to be low. With node A low, p-channel transistor 14 is turned on and node B and output 24 will be high, i.e., at the voltage of V R or 5 volts.
With a logic level 0 (0 volts) at input 38, p-channel transistor 32 will be turned on, n-channel transistor 34 will be turned off and output 36 of inverter 30 will be high. With input 38 low, n-channel transistor 16 will be off. High output 36 will turn on n-channel transistor 18 causing node B to be low which will turn on p-channel transistor 12 causing node A and output 22 to be high.
The present invention provides a solution to a problem that arises if power is applied to level shifter 10, i.e., at V R , before power is applied at inverter 30, i.e., at V C , and transistor 20 is not present. With no voltage applied at V C , n-channel transistor 16 and n-channel transistor 18 will be turned off. When voltage is then applied at V R , and with no transistor 20 present, p-channel transistor 12 will begin to turn on resulting in an intermediate voltage at node A and p-channel transistor 14 will begin to turn on resulting in an intermediate voltage at node B. With no transistor 20, the intermediate voltage at node A and the intermediate voltage at node B will exist until power is applied at V C . With an intermediate voltage at output 22 or output 24 the next or following logic stage 40 and all the logic stages which follow logic stage 40 may have both n-channel and p-channel transistors turned on at the same time resulting in dc crowbar current.
In accordance with the present invention an n-channel transistor 20 is used to prevent intermediate voltages at node A and node B when power is applied at Vn before power is applied at V C . The drain of transistor 20 is connected to the common connection between the drains of p-channel transistor 14 and n-channel transistor 18, the source of transistor 20 is connected to ground and the gate of transistor 20 is connected to node A.
In operation, when power is applied at V R at a first time and with no power applied at V C , n-channel transistors 16 and 18 will be turned off. As the voltage at V R begins to rise, both p-channel transistor 12 and p-channel transistor 14 will begin to turn on. This will cause the voltage at node A and at node B to begin to rise. If the voltage at node A rises enough to begin to turn on n-channel transistor 20, then node B will be strongly pulled down to a low value. This causes p-channel transistor 12 to turn on which causes node A to go to a high value. Thus, the problem of an intermediate voltage going to a logic gate that follows level shifter 10 has been solved because output 24 will be at a reference voltage (ground) and output 22 will be at the voltage of V R .
In the preferred embodiment, FIG. 1, the drain of n-channel transistor 20 is connected to the drain of p-channel transistor 14. It will be understood that alternatively, transistor 20 could have been connected as shown in FIG. 1a, where a prime (') is used to denote similar components. In FIG. 1a, transistor 20' has its drain connected to the drain of p-channel transistor 12', its source connected to a reference voltage (ground) and its gate connected to node B'. When connected in this way, if the voltage at node B' rises enough to turn on transistor 20', then the voltage at node A' will be pulled down to a low value. With reference to FIG. 1, this would cause p-channel transistor 14 to turn on which would cause node B to go to a high value so that output 24 would be at ground and output 22 will be at voltage V R .
Referring again to FIG. 1, there are differences in the delay introduced by level shifter 10 when input 38 goes from low to high as compared to when input 38 goes from high to low. These differences can affect the pulse width of the signal.
When input 38 goes from low to high, transistor 16 is turned on and pulls down output 22. Therefore, only one transistor needed to be turned on to cause output 29, to change. When input 38 goes from high to low, transistor 16 is turned off, transistor 39, is turned on, which turns on transistor 18 which pulls down node B, which turns on transistor 19, which pulls up output 9,2 which turns on transistor 20 which also pulls down node B. Note that more transistors must be turned on to cause output 22 to change after input 38 goes from high to low. These differences in delay need to be considered in view of the specific application in order to make a choice of whether to use the connection of FIG. 1 or the connection of FIG. 1a.
In addition, inverter 30 is shown in FIG. 1. It will be recognized that logic circuit 44 may provide both input 38 and its complement or signal 36. In this case inverter 30 would not be necessary.
The present invention provides a solution to the problem of power supply zones being applied at different times. The solution includes a single additional transistor which may easily be designed into digital logic circuits.
The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description.
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Logic level shifter for coupling a first logic circuit having a first voltage level power supply to a second logic circuit with the shifter and the second logic circuit having a second voltage level power supply and with the second voltage level supply applied at a time when the first level voltage supply is not applied. The level shifter maintains its outputs at either a reference ground voltage or the second level voltage when the second level voltage supply is present and the first level voltage supply is not present.
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FIELD
[0001] Illustrative embodiments of the disclosure are generally directed to regenerative braking control methods. More particularly, illustrative embodiments of the disclosure are generally directed to an enhanced regenerative braking control method which eliminates or reduces rough deceleration trends by compensating for brake booster torque build-up delay.
BACKGROUND
[0002] To improve fuel economy, hybrid electric vehicles (HEVs) may utilize regenerative braking, in which an electric machine applies regenerative braking torque to the powertrain of the vehicle during driver-induced friction braking of the vehicle. The electric machine converts the resulting kinetic energy into storable electrical energy which may subsequently be made available for vehicle propulsion. Regenerative braking is one of the enablers of hybrid vehicle technologies. It has been found that 15%-30% fuel economy improvements over a non-regenerative braking-capable vehicle can be achieved using regenerative braking.
[0003] During driver-induced friction braking of a vehicle, the vehicle brake controller may transmit a brake torque command to the brake booster, which applies friction braking torque to the brakes at the vehicle wheels to decelerate or stop the vehicle. Simultaneously, the vehicle system controller may transmit a regenerative braking torque command to the hybrid powertrain to initiate regenerative braking. The regenerative braking torque command may dictate the magnitude of the regenerative braking torque which is applied to the hybrid powertrain to effect regenerative braking. The regenerative braking torque command may subsequently be reported to the vehicle brake controller to indicate the point at which ramp-out, or reduction and abatement, of the regenerative braking torque has begun. In turn, the vehicle brake controller may use both the driver torque command and the regenerative braking torque command to obtain the brake torque command which induces the brake booster to apply friction braking to the brakes.
[0004] At the onset of friction braking, there may normally be a slight delay in the accumulation of friction braking torque which the brake booster applies to the brakes at the vehicle wheels. This booster torque buildup delay may cause rough vehicle deceleration trends during the delay period, as illustrated in FIG. 1 . It can be observed that at a low speed threshold (around 17.4 s) where regen is not desired, the powertrain torque starts ramping out, whereas the brake pressure starts ramping in, to compensate for reducing regen and satisfy the driver's brake request. However, due to the time response characteristics of the brake booster, the friction brake pressure starts ramping in, with a 120 ms delay. This delay, which is generally followed by an overshoot in booster pressure, causes relatively rougher deceleration trends, as can be verified from the deceleration plot. The delay is the time rate of change of deceleration and can reach 0.13 g/s, which may be manifested as a jerk that can be felt by professional drivers.
[0005] Typical booster torque buildup delay periods are on the order of 100-200 ms with 5 bar maximum overshoot.
[0006] The regenerative brake torque ramp down may be delayed as a solution, i.e. to compensate the brake booster delay, but reporting the delayed regenerative braking torque to the brake module may further increase friction brake ramp up delay as the friction brake ramp in is computed within the brake module by subtracting the regenerative braking torque from the total driver brake request.
[0007] Therefore, it may be desirable to report the undelayed, or raw, ramp-out of the regenerative braking torque to the vehicle brake controller at the onset of friction braking. Inducing such a delay in regenerative braking torque and instead of reporting this delayed regenerative braking torque, reporting the undelayed, or raw, regenerative braking torque to the brake module may yield synchronous ramp-up of friction braking to compensate for and reduce the effect of the booster torque buildup delay, eliminating or reducing rough deceleration trends which would otherwise occur during the booster torque buildup delay period.
SUMMARY
[0008] Illustrative embodiments of the disclosure are generally directed to a regenerative braking control method. An illustrative embodiment of the method includes obtaining a vehicle speed at onset of transition from regenerative braking to friction braking of a vehicle, comparing the vehicle speed to a threshold value, applying a delay for the regenerative braking torque and reporting a raw , or undelayed, regenerative torque ramp-out signal to a vehicle brake controller at onset of friction braking.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Illustrative embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:
[0010] FIG. 1 is a figure showing the problem to be solved, i.e. the booster delay and the jerk caused by the delay;
[0011] FIG. 2 is a block diagram which illustrates an exemplary enhanced regenerative braking control method;
[0012] FIG. 3 is a graph with regenerative torque command plotted as a function of time, more particularly illustrating a 100 ms delay of regenerative braking torque ramp-out, and the raw, or undelayed regenerative braking torque ramp out that is reported to the vehicle brake controller to compensate for a booster torque buildup delay of 200 ms corresponding to a brake pedal input of 25%.
DETAILED DESCRIPTION
[0013] The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the claims. Moreover, the illustrative embodiments described herein are not exhaustive and embodiments or implementations other than those which are described herein and which fall within the scope of the appended claims are possible. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
[0014] Referring to FIG. 2 , a block diagram 100 which illustrates an exemplary embodiment of an enhanced regenerative braking control method is shown. At the onset of friction braking of a vehicle, a vehicle system controller 101 commands a regenerative braking torque command 102 . The regenerative braking torque command 102 may initiate ramp-out (reduction and elimination) of regenerative torque applied to the hybrid powertrain 105 during transition from regenerative braking torque to friction braking of a vehicle. Depending on the speed (V) of the vehicle at the onset of friction braking, the regenerative braking torque command 102 may be subjected to a delay ( 104 ), with an algorithm shown in 108 to compensate friction braking ramp up delay.
[0015] In FIG. 2 , V regen ramp-out is a calibration parameter which corresponds to the vehicle speed at which regenerative torque ramp-out, or reduction and elimination of the regenerative braking torque at the hybrid powertrain 105 , is initiated. In some applications, V regen ramp-out may be about 8 km/hr. V regen ramp- out+1 may be a higher threshold value than V regen ramp-out (such as 9 km/hr, for example and without limitation) whereas V regen ramp-out −1 may be a lower threshold value than V regen ramp-out (such as 7 km/hr, for example and without limitation).
[0016] In the event that V is greater than a lower threshold speed (V regen ramp-out−1 ) and less than a higher threshold speed (V regen ramp-out+1 ), the regenerative braking torque command 102 may be delayed with respect to the algorithm at 108 . In that case, the delayed regenerative braking torque command 104 may be transmitted to the hybrid powertrain 105 . Therefore, the delayed regenerative braking torque command 104 may delay ramp-out of the regenerative braking torque which is applied to the hybrid powertrain 105 . The time period or magnitude of delay between the raw regenerative braking torque command 102 and the delayed regenerative braking torque command 104 may correspond to the friction braking, or the booster torque buildup delay of the vehicle brake system at the onset of transition from regenerative braking to friction braking.
[0017] In the event that V is greater than V regen ramp-out +1 or less than V regen ramp-out −1, there may be no delay in the regenerative braking torque command 102 , according to the algorithm 108 and the estimated regenerative braking torque at wheel level 103 may be broadcasted to vehicle brake controller.
[0018] Again depending on the speed (V) it may be determined whether the raw, or undelayed regenerative braking torque command 102 or the estimated regenerative braking torque at wheel level 103 is reported to the vehicle brake controller, according to algorithm 109 . During delaying regenerative braking torque command which corresponds to a V that is greater than a lower threshold speed (V regen ramp-out −1) and less than a higher threshold speed (V regen ramp-out +1), the raw, or undelayed regenerative braking torque command 102 may be broadcasted to the vehicle brake controller. Therefore, at the onset of friction braking, the raw, or undelayed regenerative braking torque command 102 may indicate to the brake controller 106 that ramp-out of the regenerative braking torque at the hybrid powertrain 105 is underway although application of regenerative braking torque to the hybrid powertrain 105 is actually being maintained and ramp-out has not been initiated.
[0019] Consequently, the vehicle brake controller 106 may calculate the brake torque command by subtracting the regen torque 107 , which is actually the raw, or undelayed regenerative braking torque command 102 (thinking it is the actual estimated regenerative braking torque at wheel level) from the total driver braking torque command. The vehicle brake controller 106 may transmit the calculated brake torque command to the brake booster (not shown), which applies friction braking to the brakes (not illustrated) of the vehicle.
[0020] After the friction braking has been applied to the brakes for a time which corresponds to the booster torque buildup delay, the regenerative braking torque may be ramped out. By means regenerative braking torque ramp out and friction braking ramp in may be synchronized, and the rough deceleration trend which may otherwise occur during the booster torque buildup delay period may be eliminated or reduced.
[0021] At a speed lower than a lower threshold speed (V regen ramp-out −1) estimated regenerative braking torque at wheel level 103 may be broadcasted again to the vehicle brake controller 106 . The vehicle brake controller 106 may calculate the brake torque command by subtracting the estimated regenerative braking torque at wheel level 103 from the total driver torque command and command friction braking ramp-in in the usual manner, to avoid overshoot of the friction braking ramp in.
[0022] A graph with regenerative torque command plotted as a function of time is shown in FIG. 3 . The graph illustrates a 100 ms delay in regenerative braking torque command during ramp-out, during a vehicle speed V that is less than a higher threshold speed (V regen ramp-out +1) and greater than a lower threshold speed (V regen ramp-out −1). The graph also shows the raw, or undelayed regenerative braking torque command that is broadcasted to the vehicle brake controller in order to synchronize regenerative braking ramp out with friction braking ramp in. Together with the powertrain response time, the total time between the estimated regenerative braking torque at wheel level and the raw, or undelayed regenerative braking torque command compensates the booster torque buildup delay of 200 ms, corresponding to a brake pedal travel distance of 25%.
[0023] Although the embodiments of this disclosure have been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of skill in the art.
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A regenerative braking control method. An illustrative embodiment of the method includes selecting a vehicle speed at onset of transition from regenerative braking to friction braking of a vehicle, comparing the vehicle speed to a threshold value, applying a delayed regenerative braking torque ramp out to a hybrid powertrain and sending an undelayed regenerative braking torque ramp-out signal to a vehicle brake controller without at onset of transition from regenerative braking to friction braking of the vehicle if the vehicle speed falls below the threshold value.
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BACKGROUND OF THE INVENTION
This invention relates to a shotgun shell dispenser to enhance the efficiency of hand loading or reloading of empty cases or hulls by an ammunition enthusiast. It has become increasingly popular for shotgun users to self load their shells. Recovering spent cases and reloading with a desired charge and shot count saves approximately one-half the cost of ammunition and provides the self satisfaction of a uniform self-loaded shotshell. The desire for self loaded shells, particularly for high volume trap and sheet shooting has popularized the reloading of once discarded cases or hulls. While there are various types of equipment for efficient hand loading of shotshells including progressive reloaders with daisywheel carriages with automatic shot and charge dispensers, there are few devices for convenient and orderly supply of the cases to the reloader. Such devices customarily comprise stacking containers having an open side access for removal of the hulls.
Since the procedure for hand loading of spent hulls is repetitious, it is desirable to have a shotshell dispenser that continuously positions a case in precisely the same location, such that it can be grasped without altered motion and preferably without the operator having to visually remove his eyes from the packing stand when grasping the case from the casing storage container.
The shot gun shell dispenser of this invention has been devised to automatically position a shotshell case for convenient retrieval by an operator during the procedure of hand loading the case.
SUMMARY OF THE INVENTION
The shotgun shell dispenser of this invention comprises an aid to the self loader in hand loading either new or spent hulls with the necessary primer, charge, wad and shot for effective first use or reuse of the shell. Although commercially supplied shot shells are of such high consistency that improved accuracy is rarely achieved by self loading, there is a substantial savings which has increasingly popularized the reloading of spent cases or hulls, and, in many instances loading new hulls supplied by the ammunition manufacturers.
Shotshell loaders are generally lever operated press and dispensing apparatus that, depending on their sophistication, can load from 50 to 500 shells per hour. The loaders may be single stage, performing sequentially all operations on a single shell, or progressive, performing sequential operations in stages on multiple shells, usually six for the customery six steps in reloading.
To efficiently reload, even with the progressive reloaders, the materials must be readily and conveniently available. When spent hulls are collected or saved for reloading they must be sorted for size and type, since even the same size shell of different manufacturer may require a different charge, wad or shot count. Similarly, even the hull composition, paper or plastic, will determine the procedures employed, notably in crimping the ends of the loaded case. Damaged or worn cases are discarded and the useable cases arranged for reloading.
Since a substantial number of casings must be arranged for efficient processing, for example fifty or more at a stretch, it is desired that they be positioned for assembly-line style movement.
The shotshell dispenser of this invention comprises a hopper into which a plurality of cases are placed and uniformly oriented. The hopper feeds a revolving carousel in a housing that passes the shell cases past a trap opening. The trap opening dispenses a case to an access trough, which positions the shell case for easy grasping for transfer to the reloader mechanism. The trap opening remains closed so long as a shell case is seated in the dispenser trough.
The carousel continues feeding cases to the trough from the hopper until the hopper is exhausted of cases.
While the shell case dispenser was designed and sized primarily for shotshell cases, the design principles can be used for other shells and with appropriate change in size and arrangement to accommodate the differently sized and configured cartridges of single shot shells.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the shell case dispenser.
FIG. 2 is an enlarged partial view of the discharge portion of the dispenser of FIG. 1.
FIG. 3A is a schematic view of a trap mechanism in the discharge portion passing a shell case.
FIG. 3B is a schematic view of the trap mechanism blocking passage of a shell case.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the shotgun shell dispenser 10 of this invention is shown with a plurality of shotshell cases or hulls 12 to illustrate the manner of operation of the device. The shell dispenser 10 is primarily fabricated from a plastic, here a clear plastic, which is mounted on a wire leg tripod 14 for convenient counter top placement. The dispenser 10 is constructed with a large hopper 16 having a back wall 18, vertical sides 20, a top 22 and a sloped bottom 24 with a large corner opening 26. The front wall 28 comprises a removable panel 29 with a finger lift 30 for raising and removing the panel from guide slots 32. The hopper 16 can be sized to receive a desired quantity of shot shell cases, for example, from 50-100 cases, which is a convenient quantity to work with by adapt self loaders.
With the panel 29 removed, the hopper is stacked with presorted cases 12 oriented with the brass bases 34 directed against the back wall 18. The hopper is constructed such that the cases congregate for discharge at the corner opening 26, as the quantity of remaining cases diminishes.
Communicating with the corner opening 26 is a segment of a carousel reel 36. The carousel is rotatably mounted on a spindle 38 having a horizontal axis which is parallel to the orientation of the stacked cylindrical cases in the hopper. The spindle 38 is driven by a variable speed, low revolution electric motor 40 mounted on a back panel 41. The motor 40 is connected to a power source by a conventional cord 42. The reel 36 is confined within a housing comprising a cylindrical drum 43 having an upper quadrant opening 44 in common with the hopper opening 26 thereby allowing the cases contained by the hopper to freely pass to engagement with the carousel reel 36.
The carousel reel 36 is constructed with a plurality of evenly spaced vanes 46 radially projecting from a cylindrical core 48. The vanes are spaced to permit no more than a single shell case to fall into the receptacle 49 formed between adjacent vanes as shown in FIG. 1 and in the schematics of FIG. 3A and 3B. The shell cases 12 are carried around on the reel between the core 48 of the reel and the cylindrical drum 43 which retains the cases in the receptacles until they reach a trap mechanism 50 located at an opening 51 in a lower portion of the drum opposite the upper quadrant opening. The cases either are diverted by the trap mechanism 50 or continue rotating with the reel.
Selectively blocking the opening 50 is a projecting tab portion 52 of a trap lever 54 oriented at a right angle to a pendant portion 53 of the trip lever 54. At the juncture 56 of the tab portion 52 and pendant portion 53 is a horizontal journal 58, pivotally mounted in a depending yoke 60 fixed to the drum 43 above the trap opening. The trap lever 54 also includes a weight plate 62 to insure that the pendant trip lever 54 is normally in a downward position as shown in FIG. 3A. In this position the blocking tab 52 is displaced from a blocking position allowing a case 12a interdentally disposed on the reel to pass the trap mechanism and drop to the dispensing trough 64 as shown in FIG. 3B. When the case 12a is positioned in the trough 64, the case displaces the trap lever 54 and hence the end tab 52, such that the end tab 52 blocks the drum opening 51 and prevents any succeeding case 12b from passing to the trough 64. Once the case is positioned in the trough 64 is removed, the trip lever moves to its natural pendant position permitting passage of another case through the opening to the trough.
To enhance the convenience of removal of the dispensed case 12a, the trough includes an incline end wall 66 which contacts the brass shell base 34 and slides the shell forward as shown in FIG. 2. At the top of the slide wall 68 is a lip 70 having a notched end portion 72 such that the irregular crimped end 74 of the spent shot shell does not snag on the lip 70 and disorient the case as it descends to the trough 64.
In operation, the reel continues to rotate and drop shells to the dispensing trough whenever the trough is vacant. If occupied the case lodged between the vanes simply continues to cycle until it is aligned with the trap opening at a time the trough is vacant.
While in the foregoing embodiments of the present invention have been set forth in considerable detail for the purposes of making a complete disclosure of the invention, it may be apparent to those of skill in the art that numerous changes may be made in such detail without departing from the spirit and principles of the invention.
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A shotgun shell dispenser for efficient hand loading, the dispenser having a hopper into which a plurality of empty cases or hulls are oriented and stacked, a carousel reel for serial transport of casings from the hopper to a dispenser opening and a trip mechanism for releasing a single shell to a dispenser trough for convenient manual removal of the casing from the dispenser.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to four stroke internal combustion engines, and in particular to the valve timing for such engines.
2. Description of Related Art
It is known to recirculate exhaust gases back into engine combustion chamber(s) to assist in reducing overall exhaust emissions, in particular, NOx emissions.
It has been proposed in relation to two-stroke direct injected engines to recirculate exhaust gases back into a combustion chamber by running a separate conduit externally of the combustion chamber from the exhaust manifold back to the combustion chamber and/or intake manifold. See, for example the applicant's earlier international application no. PCT/AU94/00288. However, this process may, in certain applications, have a number of disadvantages. For example, the system is dependent on the pressure of gas in the exhaust manifold being sufficiently higher than that in the intake manifold to attain the required exhaust gas flow through the conduit. In addition, modifications to the engine are required to install such an exhaust gas recycling system.
During each operating cycle of a typical four stroke internal combustion engine, there is a valve overlap period, where both the inlet valve(s) and the exhaust valve(s) of each cylinder are open at the same time. The overlap period helps in the effective flow of gas through the cylinder.
The valve overlap period typically occurs between the opening of the inlet valve(s) and the closing of the exhaust valve(s), the exhaust valve closing after the inlet valve has opened such that both valves are open during the overlap period. Measured in relation to the crank angle of the engine, the inlet valve typically opens at about 10° Before Top Dead Centre (BTDC) and the exhaust valve typically closes at about 10° After Top Dead Centre (ATDC) in a conventional four stroke engine. The crank angle at which exhaust valve closure occurs is usually quite strictly determined to be in the range of between 5° and 15° ATDC in modern four stroke cycle engines, to ensure efficient operation of the engine.
The point of closing of the exhaust valve, particularly at idle and part load, regulates the quantity of exhaust gases that can flow back into the cylinder through the exhaust valve during the induction stroke of the subsequent combustion cycle. It would therefore be advantageous, under certain engine operating conditions, to delay the closing of the exhaust valve to thereby increase the amount of exhaust gases drawn back into the cylinder through the exhaust valve.
There are however limitations in the extent that the closing of the exhaust valve can be delayed in conventional carburettor or intake manifold fuel injected engines as this can lead to combustion instability in conventional four stroke engines. One reason is that the redrawing of exhaust gas into the cylinder can displace fresh fuel and air charge entrained in the bulk air intake, leading to increased combustion instability. Furthermore, if the valve overlap period in a conventional four stroke internal combustion engine is too long, fresh charge can "short circuit", passing directly from the inlet port to the exhaust port without participating in a combustion event. Clearly, this can result in significant fuel wastage as well as lead to increased HC emissions.
It is an object of the present invention to provide an improved method of controlling the operation of a four stoke internal combustion engine.
SUMMARY OF THE INVENTION
With this in mind, the present invention provides a method of controlling a four stroke internal combustion engine having at least one combustion chamber, the at least one combustion chamber having at least one exhaust valve, the method including varying the timing of the closure of the at least one exhaust valve with respect to the crank angle of the engine by advancing the exhaust valve closure at least under certain engine conditions in response to an increased engine load, and/or delaying the exhaust valve closure at least under certain engine conditions in response to a decreased engine load, wherein the timing of the exhaust valve closure varies from about 20° ATDC at a maximum engine load or at wide open throttle of the engine, to up to about 180° ATDC at idle or at low engine loads.
Particularly at low engine speeds, exhaust valve closure timing has a significant effect on engine torque. For maximum torque at low speed, it is beneficial to advance the closure of the exhaust valve. For low torque, low speed operation, the closure of the exhaust valve is delayed, preferably as far as possible without affecting combustion stability. This reduces pumping losses of the engine thereby reducing fuel consumption.
Alternatively, the timing of the exhaust valve closure may vary from about 35° ATDC at a maximum engine load or at wide open throttle of the engine, to up to about 180° ATDC at idle or at low engine loads. Alternatively, the timing of the exhaust valve closure may be limited to about 70° ATDC when the engine is at idle or at low engine loads.
The variation of the exhaust valve closure angle between advanced and delayed may be essentially linear with respect to the variation in the engine load.
Preferably, the crank angle at which exhaust valve closure occurs is determined from a look-up map dependent on engine operating parameters such as engine speed and load.
According to a further aspect of the present invention, there is provided a method of controlling a four stroke engine having at least one combustion chamber, the at least one combustion chamber having at least one exhaust valve, the method including varying the timing of the closure of the at least one exhaust valve with respect to the crank angle of the engine by advancing the exhaust valve closure at least under certain engine conditions in response to an increased engine load, and/or delaying the exhaust valve closure at least under certain engine conditions in response to a decreased engine load, the exhaust valve closure timing being at least 30° ATDC.
The four stroke internal combustion engine may include control means for varying the timing of the closure of the or each exhaust valve in response to changes in the load of the engine.
The or each exhaust valve may be actuated by a cam on a camshaft. The control means may include an auxiliary cam lobe provided on the cam in addition to its primary cam lobe. This auxiliary cam lobe may be moveable between a retracted position and an extended position whereby the auxiliary cam lobe extends beyond the actuating surface of the cam to selectively supplement the lift provided to the exhaust valve by the primary lobe, and thereby control the exhaust valve closing point with respect to the crank angle of the engine. In an alternative embodiment, the auxiliary cam lobe may be fixed on the cam such that the exhaust valve timing is permanently set.
Preferably, the auxiliary cam lobe lift comes into effect prior to the completion of primary cam lobe lift, maintaining the exhaust valve in the open position from the initial opening by the primary cam lobe to closure when the auxiliary cam lobe ceases to have effect. Alternatively, the auxiliary cam lobe may be operable to open the exhaust valve after the primary cam lobe has completed its lift function. In this case, the exhaust valve will close momentarily before being reopened by the auxiliary cam lobe. In this case, the closure of the exhaust valve for the purposes of this invention is considered to be the closure after any lift provided by the auxiliary cam lobe.
Preferably, the exhaust valve lift provided by the auxiliary cam is not as great as the lift provided by the primary cam.
The auxiliary cam lobe may be selectively operable by a hydraulic mechanism operating within the body of the cam. Hydraulic oil may be supplied through the centre of the camshaft to the cam body for this purpose. The auxiliary cam may also be actuated by compressed air (typically 600-700 KPa) possibly supplied from an existing compressor. Such a compressor may have a primary function, for example, of supplying air for a dual fluid fuel injection system.
The above arrangements provide a preset change in the exhaust valve closure timing. The present invention is however not restricted to such preset values, and the exhaust valve closure timing can be at least substantially continuously varied between a range of settings. This may for example be achieved by providing electrical actuation of each exhaust valve in place of the cams to enable the timing of the exhaust valve closure to be varied. Solenoid actuators can for example be provided for each exhaust valve.
Preferably, the engine includes a dual fluid fuel injection system. The injection system may be of the type described in the applicant's earlier International patent applications PCT/AU84/00150 and PCT/AU88/00096. As fuel injection can thereby be accurately timed, the possibility of escape of fuel directly to the engine exhaust system can be simply eliminated by injecting the fuel at such a time that it cannot escape from the combustion chamber, for example after the exhaust valve has closed. It is not possible in a conventional four stroke engine, where fuel is drawn into the cylinder through the main air inlet port as a homogenous mixture with the bulk air supply, to delay fuel intake sufficiently without risking short-circuit problems when closure of the exhaust valve is substantially delayed. Similar advantages can also be gained using a single fluid fuel injection system.
In the dual fluid fuel system as developed by the applicant, fuel entrained in compressed air is injected into the cylinder (or combustion chamber) separately from the bulk air intake. At low loads, the fuel is injected into the combustion chamber in a highly stratified manner. The combustion of the majority of fuel is thus substantially restricted to the part of the combustion chamber where the stratified fuel is deposited by an injector of the fuel delivery system. As a result, a substantial amount of exhaust gas from the previous combustion cycle can be returned to the combustion chamber without significantly affecting the combustion process in the following cycle.
Fuel supply to the combustion chamber preferably occurs by direct injection to the chamber, but may also occur via the inlet manifold if the fuel supply to the manifold is highly controlled, for example, being supplied through a fuel injection system. The fuel used in the present system may be gasoline, LPG, or any other fuel suitable for use in four stroke cycle engines.
Advantageously, it is preferred, in the operation of any aspect of the invention, that fuel is not short-circuited from the fuel supply to the exhaust system without participating in a combustion event.
In addition to the advantages in emission control gained by delaying closure of the exhaust valve, the delay can also significantly reduce the work done by the piston in drawing gases into the combustion chamber. As a result of the delay, the abovementioned overlap period when both inlet and exhaust valves are open, can be extended further into the induction stroke. This effectively increases the valve open area through which gas can be drawn into the cylinder. As the delay in closure of the exhaust valve increases, less work is expended by the engine during the induction stroke.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood from the following description of a preferred method of and means for controlling a four stroke engine with reference to the accompanying drawings.
In the drawings:
FIG. 1 is a valve timing diagram showing the typical valve timings for a conventional four stoke internal combustion engine and the exhaust valve timing of various embodiments of the method according to the present invention;
FIG. 2 is a schematic cross-sectional view of a cam with a primary cam lobe and an auxiliary cam lobe according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view of the cam of FIG. 2, showing the auxiliary cam lobe in an extended position;
FIG. 4 is a schematic front view of the cam of FIG. 2;
FIG. 5 is a schematic front view of an alternative form of a cam, similar to that of FIG. 2;
FIG. 6 is a graph plotting exhaust valve lift against crank angle for a cam similar to that of FIGS. 4 or 5, wherein the auxiliary cam lobe has not been actuated;
FIGS. 7 and 8 are graphs approximately plotting exhaust valve lift against crank angle for the cams of FIGS. 4 and 5 respectively, wherein the auxiliary cam lobe is fully extended;
FIGS. 9 and 10 are respective profile views of solid cams corresponding approximately to the graphs of FIGS. 7 and 8; and
FIG. 11 is a graph plotting pressure against volume for an Otto cycle engine and showing the effect on suction work of an embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIG. 1, the valve timing diagram shows the typical valve timing of both the inlet valve and the exhaust valve of one cylinder of a typical four stroke internal combustion engine. The opening of the inlet valve (IVO) typically occurs about 10° Before Top Dead Centre (BTDC). The closing of the inlet valve (IVC) typically occurs at about 50° After Bottom Dead Centre (ABDC).
The opening of the exhaust valve (EVO) typically occurs at about 50° Before Bottom Dead Centre (BBDC). Conventional system exhaust valve closure EVC1 typically occurs at about 10° After Top Dead Centre (ATDC).
It is necessary, in order to avoid fuel economy and hydrocarbon emission problems, particularly for low load/speed operation, not to delay EVC1 beyond about 10° ATDC in most engine applications. This valve timing provides a short overlap period A, wherein both the inlet and exhaust valves are open at the same time.
According to a first embodiment of the present invention, the exhaust valve closure can be varied between unextended EVC2 (approx 20° ATDC) and fully extended EVC3 (approx 70° ATDC). Thus, the overlap duration is extended by an amount up to that indicated by B. In this embodiment, the exhaust valve closure is delayed to 70° ATDC when the engine is operating under low loads or at idle. As greater load is applied to the engine, the delay in closing of the exhaust valve is shortened, advancing the closure of the exhaust valve. At maximum load or wide open throttle, the exhaust valve closure is advanced to 20° ATDC. When load is subsequently reduced, exhaust valve closure is again delayed.
In other embodiments, exhaust valve closure EVC3 can be delayed to up to 180° ATDC (i.e. Bottom Dead Centre). Exhaust valve closure at high loads EVC2 can also be set at more delayed timings, and a typical value would be 35° ATDC. Thus, in another embodiment, exhaust valve closure varies between 35° ATDC and 180° ATDC.
In an alternative method according to the invention, exhaust valve closure is fixed at EVC4, which is set at 45° ATDC. This value is a compromise between the benefits of long exhaust valve closure delay at low load and the preference of shorter delays at high loads. The capability of the present system in allowing long exhaust valve closure delays at low loads, results in a compromise exhaust valve closure timing which is set at a significantly delayed time in relation to the ideal maximum load or wide open throttle exhaust valve closure. In conventional systems, ideal exhaust valve closure at low load would occur at an advanced crank angle with respect to ideal maximum load exhaust valve closure. Thus, a compromise in exhaust valve timing would result in actual exhaust valve closure prior to the ideal maximum load exhaust valve closure, reducing the desired exhaust valve closure delay.
In a typical four stroke engine, the exhaust valves are cam shaft actuated, with cams on the camshaft typically engaging a cam follower of a valve tappet which in turn controls exhaust valve lift. A cam 10 according to the present invention is shown in FIGS. 2 to 4. The cam 10 includes a primary cam lobe 12 and an auxiliary cam lobe 14. The cam 10 provides an actuating surface 16 which typically engages the cam follower of the valve tappet to thereby actuate the exhaust valve.
FIG. 2 shows the auxiliary cam lobe 14 in a retracted position. This auxiliary lobe 14 can be moved to an extended position as shown in FIG. 3 to supplement the lift provided to the exhaust valve by the primary cam lobe 12. A central hydraulic oil supply 18 can be provided along the cam shaft with a separate hydraulic supply line 20 being provided within each cam 12 to the auxiliary cam lobe 14. Oil is supplied to the hydraulic supply line 20 when the auxiliary cam lobe 14 is to be extended.
When the auxiliary cam lobe 14 is in its retracted position, the valve lift is solely effected by the primary cam lobe 12. FIG. 6 shows the exhaust valve lift as a function of the crank angle of the engine when the auxiliary cam lobe 14 is fully retracted. The exhaust valve closes at EVC2 which in this embodiment is 35° ATDC, and there is no supplementary valve lift.
Extension of the auxiliary cam lobe 14 results in a change in the exhaust valve lift as shown in FIG. 7. Point 22 on the cam actuating surface 16 as shown in FIGS. 2 and 3 is a point of zero valve lift. At this point the exhaust valve is fully seated and this occurs at EVC2 (20-35° ATDC) as shown in FIGS. 6 and 7. However, because the auxiliary cam lobe 14 is extended, there is a supplementary exhaust valve lift to EVC3 (70-180° ATDC) as shown in FIG. 7.
Because the exhaust valve is at zero lift at point 22 of the cam actuating surface 16, the operation of the cam follower of the valve tappet will not be affected by the lack of support immediately following point 22 when the auxiliary cam lobe 14 is not in the extended position.
In an alternative form of the cam 10 according to the present invention as shown in FIG. 5, supplementary cam surfaces 24 are provided on opposing sides of the auxiliary cam lobe 14. These supplementary cam surfaces 24 act to support the cam follower when the auxiliary cam lobe 14 is not extended. This thereby allows the auxiliary cam lobe 14 to be positioned at any convenient location around the periphery of the cam 10 because the supplementary cam surfaces 24 support the cam follower when the auxiliary cam lobe 14 is not extended. The exhaust valve therefore does not need to be fully seated when the cam follower returns to the location of the auxiliary cam lobe 14. This enables the exhaust valve lift to be varied such that the exhaust valve remains open continuously to EVC3 (70-180° ATDC), as shown in FIG. 8.
It is preferable that the exhaust valve lift after the inlet valve opens is less than the peak lift of the exhaust valve as shown in FIG. 8. In this way, exhaust gas recirculation through the exhaust valve is restricted somewhat, and the amount of exhaust gas flowing through the exhaust valve can be more tightly controlled by the adjustment of the exhaust valve timing.
Referring now to FIGS. 9 and 10, exemplary forms of two solid cam profiles are shown. The cam of FIG. 9 in use produces an exhaust valve lift v crank angle plot similar to that shown in FIG. 7, whilst the cam of FIG. 10 produces an exhaust valve lift v crank angle plot similar to that of FIG. 8. These cam profiles can be used in solid cam constructions as shown, and can also be adapted for use in auxiliary cam lobe constructions.
The cam construction of FIG. 9 has a permanent additional raised cam portion generally indicated by the numeral 30, and not present on a standard cam. In this embodiment, the additional portion 30 supplements the exhaust valve timing by lifting the exhaust valve after the standard cam lobe 32 has finished its lift. The cam construction of FIG. 10 also has a permanent additional cam portion, shown at 34. In this embodiment, the additional portion 34 complements the standard cam lobe 32 and maintains a low exhaust valve lift for an extended period, rather than relifting the exhaust valve as occurs with the cam of FIG. 9.
FIG. 11 shows the theoretical Otto cycle for a four stroke engine, including the compression stroke 40, combustion 42, expansion stroke 44, exhaust stroke 46, and inlet stroke 48. Particularly at low loads, a substantial amount of work is expended in drawing gas into the combustion chamber during the inlet stroke 48. The amount of work expended in this way corresponds to the area on the graph between lines 46 and 48 (the inlet and exhaust strokes). In delaying exhaust valve closure, the inlet stroke path is altered to that indicated by 48a. This reduces the area on the graph between the inlet stroke line 48 and exhaust stroke line 46 by an amount indicated by shaded area 50. A corresponding reduction in pumping work is thus achieved, and fuel consumption is reduced.
The present invention therefore provides for a delay in the timing of the exhaust valve closure as the engine load decreases and/or allows advancement of the timing of the exhaust valve closure as the load is increased. In an alternative arrangement, the timing of the exhaust valve closure can be delayed to a fixed crank angle later than has generally been usefully possible in conventional four stroke engines.
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A method of controlling a four stroke internal combustion engine having at least one combustion chamber, the or each combustion chamber having at least one exhaust valve, the method including varying the timing of the closure of the or each exhaust valve with respect to the crank angle of the engine by advancing the exhaust valve closure at least under certain engine conditions in response to an increased engine load, and/or delaying the exhaust valve closure at least under certain conditions in response to a decreased engine load.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates in general to certain new and useful improvements in an automatic pool cover system utilizing cable drives for controlling wind-up and payout of a buoyant slatted swimming pool cover from a cover drum.
[0003] 2. Brief Description of Related Art
[0004] Pool covers are frequently used on swimming pools inasmuch as they provide an energy savings, keep the swimming pool relatively clean and minimize the use of chemicals to maintain safe swimming pool water. In addition, and more importantly, they are widely effective in providing additional safety features. In windy locations, a swimming pool cover is essential for maintaining pool water at a comfortable temperature and for eliminating debris which might otherwise be blown into a swimming pool.
[0005] The vast majority of swimming pool covers use electrically operated using electric motor drives. However, electric motor drive systems present numerous safety hazards and, moreover, the electric motors must be completely insulated from a water environment. Even when the pool cover drive systems are located in a separate subterranean environment in proximity to the swimming pool, rain water and other water from the swimming pool itself tends to collect in the subterranean compartment which is used for housing the electric motors and associated electrical components. Moreover, it has been recognized that at least fifty percent of failures in most automatic pool cover systems is the result of the inherent problem of water damage.
[0006] In order to overcome this problem, the present applicant designed and developed a pool cover system which totally relies upon a hydraulic drive located at or near the swimming pool. An electric power pack is provided at a remote location for pumping the hydraulic fluid. One such system is described in U.S. Pat. No. 5,184,357, dated Feb. 9, 1993, in which the applicant describes an automatic swimming pool cover using a hydraulic drive for providing cover drum rotation during extension and rotating the cover drum for cover retraction.
[0007] Automatic swimming pool cover systems frequently use flexible vinyl fabric which is sized so that it floats on the surface of the pool water. The water acts as a low friction surface reducing the amount of force required to drag the cover across the swimming pool. However, many swimming pool covers, both in the United States and elsewhere, use the buoyant slat type pool cover. This pool cover includes a plurality of interconnected buoyant slats which effectively float on the surface of the water. Moreover, the cover drum for these slatted type pool covers is usually located in a submerged condition in the body water forming the swimming pool. In these cases, electric drive systems are not effective because of the problems mentioned above.
[0008] The present applicant has proposed and has designed a pool cover system for relatively rigid buoyant slatted pool covers which relies upon a hydraulic drive. The hydraulic drive is powered by an electrically operated power pack in a remote location. The present invention relies totally upon a cable system which is powered from a remote location and, therefore, the drive can be either an electric drive, a hydraulic drive or the like.
[0009] Automatic pool cover systems utilizing interconnected rigid buoyant slats which roll up on a submerged or elevated drum are also described in U.S. Pat. No. 3,613,126 to R. Granderath and are quite popular in the United States and also in Europe. These pool cover systems utilize passive forces arising from buoyancy or gravity to propel the cover and extend the cover across the swimming pool. However, there must be some mechanism to prevent the retracted cover from unwinding responsive to these passive forces. Granderath provides a worm gear drive mechanism for winding the cover and preventing cover drum rotation when not powered. However, worm gear drive mechanisms are not effective and insufficient for the intended purposes.
[0010] There has been a need for a pool cover system in which a swimming pool cover can be driven across a swimming pool to a closed position and wound back onto a cover drum in order to an opened position in order to provide access to the swimming pool and which could be powered completely from a remote location. The present invention finds its employment in a cable drive in which the power source can be remotely located.
BRIEF SUMMARY OF THE INVENTION
[0011] A desirable solution for the buoyant slat type cover would be to provide a cover drum located in a submerged condition in a swimming pool for wind-up of the cover onto the drum and for unwinding of the cover from the drum. A cable drive system is effective for powering the drum to roll the cover back onto the cover drum in order to provide access to a swimming pool and for controlling the speed of unwinding of the cover from the drum as a result of buoyant or gravitational forces.
[0012] In accordance with the present invention, a cable drum is located at a remote location and is powered from a separate power source at that remote location. The power source could be either an electric motor or a pneumatic drive motor or any other type of motive means. The cable drum is also trained about a separate cable drum mounted on the cable drum shaft which carries the cover. Thus, cable can be pulled from the cable drum on the cover drum shaft and also wound onto the powered cable drum. In like manner, speed of movement of payout of the cable from the powered cable drum can be controlled by a brake means at a remote location to thereby control any unwinding of the cover from the cover drum.
[0013] The drive system of the invention utilizes the extensive upward buoyant force of the cover and its ability to cover the swimming pool and converts this force into a usable controllable drive means. In the present invention, the system employs a stainless steel cable or other non-corrosive cable or force transmitting means and winds this cable onto the cover drum or, otherwise, to a separate reel attached to the cover drum while the cover is being propelled across the swimming pool by its own inherent buoyant force. In this case, the drum pays out the cable at a controlled and essentially constant rotational speed by a winch-like means operated either by a hydraulic or electric motor at a location remote from the swimming pool.
[0014] On a floating slat type of cover there are many applications where the cover drive system must be placed well below the surface of the water in order to prevent interference with other pool construction such as pools with continuous gutters and overflow weirs. Also in instances where two covers unwind from the center of the pool as described in the Granderath patent EP 369038 the drive system must necessarily be mounted in bottom of the pool to be out of the way of swimmers while the pool is being used. Another reason is that sometimes pool covers are fitted to existing pools and for convenience and aesthetics the cover drum is placed at the bottom of the pool. These cover systems are typically powered by penetrating the cover drum drive shaft through the pool wall with a shaft sealing system. This means that an accessible maintenance chamber on the other side of the pool wall must be constructed at the full depth of the pool or more, and at considerable expense. Furthermore, the rotating shaft seals at these depths must be more substantial so as to prevent leakage of water from the pool at the higher pressures. Another possibility is to use a chain drive coupled to a drive enclosure just above the surface of the water. Stainless steel chain drives are costly and furthermore over the distances used, they need idlers to keep the chain tight. For safety reason, in some applications guards are also required, which take up space.
[0015] Recently cover drive drums have been available which incorporate an electric motor inside of the drum. Typically these drives incorporate a planetary gearing system. Since unlike worm gear reducers, these planetary gear systems do not prevent back driving or self braking, they must have a friction brake incorporated to stop the cover at any time. Furthermore, these brakes are strictly an off/on brake and do not counterbalance the natural buoyant force of the cover when unwinding and will not control acceleration. Typically some type of additional electrical motor braking is required. These internal drum motors are considerably more expensive and require good sealing for the electrical supply and control wires especially at greater depth and pressures. A further problem is that the electrical braking must necessarily dissipate the energy generated as heat. This causes thermal expansion and escape of air through the seals in heating, and which will, in turn, subsequently pull in water through the seals because of the vacuum created when the cover drum cools. This water in an electrical environment eventually can be disastrous on the reliability of the electrical components inside the cover drum.
[0016] One of the consequences of placing the cover well below the surface of the water is that more of the buoyant cover is submerged and creates a greater buoyant force. For example on a typical 20 feet wide by 40 feet long swimming pool, with the roller beneath the pool floor, the torque on the drive shaft can be as high as 6000 inch-pounds in the fully open position, or conversely an upward force of 600 lbs acting on a ten inch lever arm. This torque reduces to about 1800 inch-pounds at the completely closed position and the moment arm is reduced to about three inches. Buoyant covers, particularly covers well submerged below the surface of the water, have enough inherent buoyant energy in the unwinding or covering direction to cover the pool without any input of energy from any external source. In fact, it has been the experience that the cover will accelerate to such a linear covering speed as to cause buckling of the cover and other problems with control. For this reason braking is provided in the unwinding or covering direction to prevent acceleration and maintain a reasonable covering velocity.
[0017] Another problem with direct drive to the cover drum for the floating cover is that there is no provision or means to detect if a problem had occurred with interference or blockage of the cover as it travels while floating across the pool. Consequently, when such a blockage occurs the cover drum will continue rotating and unwinding causing the cover to bunch up in the well and often causing severe and frequent irreparable damage to the cover slats. Considerable work is required to untangle the jammed and damaged cover materials.
[0018] This invention possesses many other advantages and has other purposes which may be made more clearly apparent from a consideration of the forms in which it may be embodied. These forms are shown in the drawings forming a part of and accompanying the present specification. They will now be described in detail for purposes of illustrating the general principles of the invention. However, it is to be understood that the following detailed description and the accompanying drawings are not to be taken in a limiting sense.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Having thus described the invention in general terms, reference will now be made to the accompanying drawings in which:
[0020] [0020]FIG. 1 is a fragmentary schematic perspective view, partially broken away, showing one form of automatic pool cover system in accordance with the present invention; and
[0021] [0021]FIG. 2 is a fragmentary schematic perspective view, partially broken away, and showing a modified form of automatic pool cover system in accordance with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0022] Referring now in more detail and by reference characters to the drawings, there is illustrated in FIG. 1 an overall automatic pool cover system in combination with a swimming pool. This pool cover system specifically shows the drive mechanism in a subaqueous condition and with a special subterranean compartment as hereinafter described.
[0023] More specifically, there is illustrated a pool deck 70 surrounding a swimming pool wall 72 and which provides an interior swimming pool cavity 74 containing water therein. The automatic pool cover mechanism is located in a separate subterranean compartment 76 formed by a subterranean wall 78 , as shown. A pool cover lid 80 is disposed over the compartment 76 and provides access thereto.
[0024] A cover dispensing and winding mechanism 82 is provided and includes a subaqueously located cover drum 84 . Generally, the cover dispensing and winding mechanism 82 is located in its own separate compartment for easy access and for purposes of cleaning and repair.
[0025] By further reference to FIGS. 1 and 2, it can be seen that the cover drum 84 is mounted on a drum shaft 90 which projects through a sealed aperture 91 in the wall 78 , and which is also hereinafter described in more detail. The drum shaft may also be contained in an interior compartment and mounted to the inside of the pool wall. A buoyant slat type cover 92 is wound upon the cover drum and may be unrolled therefrom to extend over the upper surface 94 of a swimming pool body of water.
[0026] Also mounted on the drum shaft 90 and being co-axial with the drum 84 is a cable reel 96 and which receives a cable 98 . The cable 98 is trained about a cable spool 100 which is, in turn, coupled to and driven by a motor 102 . It can be observed that the motor has an output shaft 104 which is connected to a worm gear reducer 116 , the latter of which serves to provide a braking action to the cover drum. The reducer 106 is mounted to the cable spool 100 for rotating same. Since the steel cable may be as thin as two or three millimeters, the reel could be mounted on the inside of the pool wall. At approximately twenty revolutions of the drum to close the pool, a three to four layer cable buildup would amount to a cable reel width of only eight to 10 millimeters.
[0027] The motor 102 can be any type of power drive as, for example, an electrical motor, or a hydraulic motor, or the like. It is only important to provide rotating power to the spool 100 upon a driving command. It should also be observed that the cable spool 102 and the drive motor 102 is remotely located with respect to the pool cover mechanism 82 . In this way, the cable can be trained through a wall or other structure and connected to the spool 100 when the latter is in a remote location.
[0028] The cover which is used in the system of the present invention is preferably a buoyant type cover comprised of a plurality of interconnected buoyant slats. When this cover is wound onto a drum, particularly when the latter is in a submerged condition, as shown in FIG. 1, the diameter of the drum will increase. The torque on the drum shaft 90 increases and is the product of the upward buoyant force of the slat area unwound from the cover drum and still submerged beneath the surface of the water multiplied by the instant radius of the cover drum. It can be observed that there is a buoyant force and/or gravitational force which causes the cover to unwind from the drum and thereby travel across the swimming pool. Thus, the cover will literally drive itself across the swimming pool to the closed position, although some braking means must be provided to control the speed of the cover drum and thereby preclude the cover from contacting an end position with any substantial force which would damage the cover. However, in order to wind the cover upon the drum to thereby open the cover, a driving force is required and that driving force is provided by the cable through the driven cable spool 100 .
[0029] One means to brake the cover drum in the unwinding direction, when the cover is moving to the closed position, is a worm gear reducer, as shown. Another means, such as a ratchet and pawl mechanism, can also be used. In this case, the ratchet and pawl mechanism would be connected to a shaft extending from the opposite side of the spool 100 . In this way, the pawl engages the ratchet and precludes unwinding of the cover from the spool. Moreover, the ratchet and pawl does not provide a braking action, as such.
[0030] In place of a worm gear reducer or a ratchet and pawl, it is possible to use a conventional braking mechanism, such as a disc (not shown), engaged on the shaft and engaged by brake shoes, similar to that shown in FIG. 2. For this purpose, any type of braking mechanism may be employed in accordance with the present invention.
[0031] It can be observed that when the cover is unwinding from the drum, it will cause an unwinding of the cable 98 from the spool 100 and which will thereupon wind onto the reel 96 . In addition, when it is desired to wind the pool cover onto the drum, the motor 102 is energized causing rotation of the spool 100 and the causing the cable 98 to rotate the drum shaft 90 as well as the reel 96 and the cover drum 84 .
[0032] One of the principle problems in operating a cover drum when the latter is in a subaqueous condition is the fact that necessary precautions must be taken to preclude water from contacting the actual drive mechanism, such as an electric motor or hydraulic motor. Usually, this requires formation of separate compartments and sealed openings through which a drum shaft would extend. Notwithstanding, and even with these precautions, water still tends to collect in the drive compartment.
[0033] In accordance with the present invention, it is possible to run the cable through any subterranean structure or other structure so that it does not encumber access to the swimming pool itself. In this case, the cable 98 is shown as being trained around the reel 96 and over an idler roller 112 through a retaining tube 114 to the spool 100 . As indicated previously, the spool 100 and any drive motor, such as the motor 102 , would be located in a completely remote position and thereby insulated from any potential hazards of water. This system is easy to install and relatively inexpensive. Moreover, its simplicity provides simple operation and relatively trouble free operation. Most importantly, it solves the problem of attempting to power a drum shaft, such as the drum shaft 90 , without compromising the safety of the power source.
[0034] [0034]FIG. 2 illustrates an alternate embodiment of the present invention. In this case, reference numerals used to identify those components in FIG. 1 will be used to identify like components in FIG. 2.
[0035] In the embodiment of the invention as shown in FIG. 2, there is a conventional brake mechanism 120 which is used in place of the worm gear reducer 106 . In this case, there is provided a brake disc 122 acted upon by brake shoes 124 . A suitable control mechanism would be provided for operation of the brake mechanism. In this way, a braking force can be provided, if desired.
[0036] Also in the embodiment of the invention as illustrated in FIG. 2, a second reel 126 is also mounted on the drum shaft 90 adjacent to the spool 100 . The spool 100 continues to pay out and receive the cable 98 . However, a second cable 128 is trained about the second reel 126 , also in the manner as shown in FIG. 2. The second cable 128 similarly winds up onto the reel 100 . Moreover, it can actually be continuous with the cable 98 , if desired.
[0037] In accordance with the above-identified construction, it can be observed that a controlled drive is provided in both directions, that is, the first cable 98 would provide a positive drive to roll cable onto the drum. The second cable 128 provides a controlled rotation of the drum shaft 90 and, hence, the drum 84 , and thereby provides a controlled payout of the cover 92 . This mechanism is highly effective, particularly when used with a brake mechanism, such as the mechanism 120 .
[0038] The system as illustrated in FIG. 2 is equally as effective as the system in FIG. 1, in that the power source and the spool are located in a remote location with cables again being trained in an underground structure or other structure where the cable is unobtrusive. Thus, the cable drive of the invention provides a very effective means, both for providing driving power for winding up the cable and also for providing a braking power to the cover.
[0039] It should be understood that the aforementioned system may also be applied to systems where rollers are placed above the water surface and subject to gravitational as opposed to buoyant forces. This arrangement would be equally effective.
[0040] Thus, there has been illustrated and described a unique and novel cable operated automatic pool cover system using buoyant slat pool covers and which thereby fulfills all of the objects and advantages which have been sought. It should be understood that many changes, modifications, variations and other uses and applications which will become apparent to those skilled in the art after considering the specification and the accompanying drawings. Therefore, any and all such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention.
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A control system for controlling the movement of a pool cover comprised of interconnected rigid buoyant slats and which uses a driven cable through a remotely powered source as a primary drive mechanism. The swimming pool cover is typically mounted on a drum and often in a submerged condition. In order to overcome the buoyant forces, the drive and control means must provide a braking action to the pool cover which would tend to unwind from a drum as a result of buoyant forces. The drive mechanism employs a cable drive which will wind a cable upon a cable reel or drum mounted in a remote location with respect to the cover drum. Cable could be trained from the cover drum to this cable drum in order to power same for rotation in at least a wind-up direction and could be used for controlling a braking action in the unwinding direction.
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REFERENCE TO RELATED APPLICATIONS
This application is entitled to the benefit of provisional patent application Ser. No. 60/807,193, filed Jul. 12, 2006; such benefit is hereby claimed under 35 USC 119(e), and the disclosure thereof in its entirety is hereby incorporated by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO SEQUENCE LISTING
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to drying items such as gloves, mittens, and other garments or parts thereof. More particularly, the invention relates to a device for holding such items in a substantially open position whereby drying can occur by the flow of air therethrough.
2. Description of Related Art
Thorough drying of wet or damp articles of clothing subsequent to exposure of the articles to wet weather conditions, incidental emersion, or simply following routine laundering of the articles is important to comfort and health of the wearer. Incomplete drying can bring discomfort and chills to those individuals who must wear the articles during work or recreation.
Further, allowing damp articles of clothing to lie around for extended periods of may result in an unwelcome experience for the individual who must then wear such clothing into the cold outdoors. Items of clothing left damp and dormant for a significant period, particularly woolens or leather, quickly develop a musty scent usually found difficult to eradicate. This scent may signal the growth of mildew which ultimately may damage the clothing fabric and/or introduce allergens and/or pathogens. Examples of clothing articles most adversely impacted might include leather or woolen gloves, mittens, socks, stockings, shoes, boots or portions of jackets, slacks, caps, shirts and similar items.
A significant problem is that timely, thorough drying of such items too often is inconvenient or even impossible. Placing the items into an electric or gas heated dryer of the standard type and capacity typically assigned to handling large volumes of clothing takes considerable time and attention, and can be a waste of energy expense. Also, such treatment may result in damage (e.g., shrinkage or parching) to the items themselves. Lack of an effective alternative has driven some to desperate and even dangerous measures.
Fire department authorities repeatedly report damaging fires resulting from placement of mittens, socks or similar items in a microwave oven or their suspension from a mantel of an open fireplace. Injuries have been reported as the result of insertion of hot curling irons or other heating implements such as glowing light bulbs into the fabric of wearing apparel.
Though not usually hazardous, placement of damp clothing items on a hot radiator or against a vented outlet of a forced-air heating system can be discouragingly slow and bring disappointingly inadequate results. Heat radiated or blown against the outer surfaces of the items may tend to over-dry the surface of an item while under-drying its interior confines. Typically, this results in parched, heat-damaged surface areas while stubborn dampness continues to dwell within. Faced with the choice of wearing damp gloves, mittens or other items into the cold morning air, many elect to leave them behind. In extreme climates this can, of course, be a regrettable choice.
Over the years, a great number of devices and solutions have been proposed for facilitating the drying of damp clothing items. Each falls considerably short of expectations in a number of ways. The devices or solutions either are too expensively complex in structural design to be economically manufactured, or they simply are ineffective in application. The present invention represents a solution which is a significant step forward with respect to the prior art.
For example, Benjamin's U.S. Pat. No. 4,991,756 presents a device for drying wet gloves or mittens, or portions of other wet clothing. Benjamin's device is formed as a hollow cylinder or is slightly tapered from cylindrical to slightly conically shape. The main portion of Benjamin's dryer includes a grid of multiple ventilation holes that are square or diamond shaped to facilitate evaporation of moisture.
Benjamin's dryer device can be made of flexible plastic material and molded into its final shape (and also into such a shape that a number of said dryers can be “nested” inside each other). Alternatively, Benjamin's dryer device can be molded in an essentially planar condition and then forced by the user into its shape described above, by slight exertion of hand pressure.
The shape of Benjamin's device is such that it may be inserted into a glove or mitten so as to allow air to circulate to remove the moisture and thus dry the glove and/or its lining. At its larger end, a tab with a through-hole or S-hook is provided for hanging the dryer unit during a drying process. This device is complex in its design to the point of being difficult to fabricate economically, and results in a surface texture and shape that resists efforts to place it within damp items to be dried.
In U.S. Pat. No. 5,983,518 issued to Ellenburg, a glove drying device is described as comprising a slightly tapered shell for holding the glove, and a clamp for attaching the tapered shell to a golf cart. As the golf cart is driven, movement of the device through the surrounding air serves to dry the glove. Alternatively, the shell may be attached to a golf bag and includes a battery powered fan for drying a glove placed thereon. Applicant notes that golf carts hardly move at great speeds to effect rapid drying; wind around a golf bag will do little if any drying. Besides, the Ellenburg device is not adaptable to use by people arriving home on a cold wet night with gloves that must be dried by morning.
Auckerman's U.S. Pat. No. 5,604,993 introduces another golf glove dryer. This device includes a perforated hollow drying form in the shape of a hand. A tube is mounted to the inside of the drying form in order to improve air flow into the interior of the form. A heater is provided for mounting inside the tube in order to heat the air which flows into the drying form and to enhance the air flow. This, of course, is a single-use device requiring very specific manufacturing specifications.
Disclosed in Dofka's U.S. Pat. No. 5,406,717 is a compact drying rack for gloves. Dofka's invention includes a drain basin for fluid drip collection. Two pylons are situated within the drain basin and serve as bases for vertical, hollow support rods on which are mounted spread ring discs which engage the inside of glove surfaces to facilitate drying.
Positioning the utility gloves on Dofka's drying rack permits air drying of utility gloves thereby destroying pathogens present on wet gloves, preserves the quality of the glove material, avoids contamination to the work site by eliminating pooling of fluids on wet gloves deposited on counter tops.
Bader's U.S. Pat. No. 5,125,169 offers a relatively complex glove drying apparatus and method wherein an internal sliding mechanism includes fingers movable from retracted position to expanded position. When the fingers are in retracted position the sliding mechanism may be inserted into the glove and then expanded into glove drying position. A non-constant cross-section configuration of the fingers allows for air circulation within the gloves thus promoting drying thereof.
Like Bader's device discussed above, the Willenbacher, Jr. U.S. Pat. No. 5,117,565 illustrates a glove drying frame configured as a human hand. In this instance the drying frame is formed of a wire mesh hollow body to accommodate a glove thereon, with the hollow body mounting a support clip to a wrist portion of the hollow body to permit suspension of the hollow body permitting free-flow of drying air to be directed interiorly of the hollow body. The Willenbacher, Jr. invention further includes a mounting framework for support of a plurality of hollow bodies permitting directing of a drying medium within the hollow bodies.
Appelt's U.S. Pat. No. 3,477,622 presents a glove dryer comprising a structure simulating a hand, and which may be folded flat during non-use. Mechaneck's U.S. Pat. No. 3,409,142 discloses a glove drying stand which may be configured to dry multiple gloves. The Mechaneck dryer may stand upright on its own or be attached laterally for its support.
In Published U.S. Patent Application No. 2004/0181963, Morris shows an insert disposed in a glove to open up the glove and allow the flow of drying air to the inner surfaces of the glove. A cruciform shaped opening is provided in a central portion of the insert. The opening is adapted to interlock with a mating cruciform member on a drying tree for drying in ambient air. Alternatively, the insert with glove mounted thereon can be disposed in a gas or electric dryer.
DuRapau's U.S. Pat. No. 7,121,017 and No. 6,962,004 present drying apparatuses for boots and gloves including a body portion with an upwardly extending drying member. The member includes an upper portion for holding an item of apparel, and a platform coupled to the body portion. The platform can be moved into a first generally horizontal position over the drying member and can be moved into a second, non-horizontal position not over the drying member such that a user has access to the upper portion of the drying member. The drying apparatus can include an air freshener.
While a great number of dryers and drying methods presently exist within the prior art, all are burdened by complexity or manufacture and ineffectiveness in application. None holds the advantages of the present invention, particularly in terms of ease of placement of the dryer unit within items to be dried. Further advantages of the present invention are its simplicity and economy of manufacture, and enhanced results from its application.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 shows a perspective of the device as viewed from its larger, substantially open end and tapering toward a smaller substantially closed end;
FIG. 2 illustrates a side elevation of the device shown upright as it rests on its larger end;
FIG. 3 is a plan view at the larger end of the device looking into the larger substantially open end of the device, and through toward its smaller end.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a passive dryer device generally designated as 1 . Dryer device 1 is both portable and free-standing, and is formed generally about a central axis A. It has a shape affording stacked shipments, and nesting storage of multiple units during non-use.
Dryer device 1 finds uniquely useful application to wearing apparel (not shown) which is, at least in part, generally tubular in shape, but of course adaptable to non-tubular shapes as well. It is important, however, that the wearing apparel item to be dried is structured to permit insertion of dryer device 1 . Examples of such apparel (while in no way intended as limiting the application of dryer device 1 ) are gloves, mittens, socks, stockings, and the like. Other apparel items to which device 1 may be applied include shirt sleeves, certain shoe or boot designs, hats, stocking caps, and the like.
Dryer device 1 enjoys a unique configuration to facilitate its insertion for drying items from inside-out. It is formed to mount on typical heat-outlets such as a building's forced-air vents. As illustrated in FIG. 1 , dryer device 1 includes a relatively larger, substantially open base or portion 2 and a relatively smaller second end or portion 6 terminating at a substantially closed end 7 .
Both portions ( 2 , 6 ) have an inner and outer surface substantially smooth so as to facilitate relative mounting thereupon of any items to be dried, as well as enabling nesting or stacking as discussed hereabove. An intermediate or shoulder portion 4 is configured and located so as to adjoin portions 2 and 6 and is, for the same reasons just discussed, substantially smooth in nature on both its inner and outer surfaces.
Overall, dryer device 1 presents a generally conical configuration which narrows or tapers from its relatively larger substantially open base portion 2 , to its second portion 6 , terminating at end 7 . However, rather than a uniform tapering of the dryer device 1 from first portion to second portion ( 2 , 6 , 7 ), the device 1 decreases in at least two tapering stages and at differing tapering rates or angles relative to central axis A. To form a user friendly dryer configuration, the relationships of these differing angles is important as will now be explained.
Each portion ( 2 and 6 ) has an outer surface configuration defined generally by a surface of revolution about the dryer device central axis. If the surfaces of revolution of the initial portion 2 and second portion 6 were to be extended so as to intersect the device central axis A, the intersection angle of the surface of revolution extension for portion 2 will be greater relative to that of portion 6 . The general effect is that the dryer device 1 of the present invention presents a narrowed axial extension toward its end 7 as is evident in FIGS. 1 and 2 .
This narrowed axial extension in the form of portion 6 facilitates its easy insertion into even the smallest item of apparel such as a child's mitten. (Note: While the expressions “generally conical” and “surface of revolution” are, for convenience of explanation and understanding, employed in describing this invention, it will be apparent that any equivalent shape such as “generally polygonal” will apply just as well, with tapering reductions in width following the same basic scheme to be described below.)
Between (and interconnecting) the first portion 2 and second portion 6 is a generally annular transition section or shoulder 4 . This narrowing transition section, shoulder 4 , also has an outer surface configuration defined generally by a surface of revolution about the dryer device 1 central axis. If the surface of revolution of shoulder 4 were to be extended so as to intersect the device 1 central axis A, it would do so at an angle greater than that of both the first and second portions 2 and 6 . This shoulder 4 configuration serves to step-up the support surface for ever-larger items of clothing and the like, as end 7 is inserted relatively deeper into the apparel item.
Each of the portions 2 , 4 , and 6 (as well as end 7 ) is provided with a set of air passages, 12 , 14 , 16 and 18 respectively. Compared to prior art devices, the number of air passages in the portions 2 , 4 and 6 is relatively minimal. By limiting the collective (or sum of), substantially open areas in each said first, second and intermediate dryer portion 2 , 4 and 6 to less than half of each said portion collective surface area, the resultant device 1 structure will be substantially rigid and stable, and notably more easily inserted into clothing items without deforming.
In the present context, “collective open area” refers to the square-inch sum of open areas for a portion 2 , 4 or 6 . Similarly, “collective surface area” refers to the total overall surface area for each portion 2 , 4 or 6 . It will be appreciated that air forced through fewer openings relative to overall surface area of a dryer device will flow with substantially increased back pressure than in a device where the vast majority of the surface area is effectively divided into a comparably greater number of adjacent passages.
Passages 12 , 14 , 16 are bordered by their smooth and uninterrupted edges to avoid snagging the material or fabric of items mounted thereon. As more clearly illustrated in FIG. 3 , passages 12 , 14 and 16 are further defined so as to slightly expand in volume capacity from an inside surface toward outside surface of each portion ( 2 , 4 , 6 ) of device 1 .
During use of dryer device 1 , air may be forced from a typically heating duct so as to flow into opening 20 . The air then is moved in a continuously reduced pathway toward and into the shoulder portion and second portion, respectively. Along its pathway of flow, the air is forced through passages 12 , 14 and 16 , as well as through holes 18 in end 7 , and into an interior of any clothing item mounted thereon. (Note: The circle labeled 19 in FIG. 3 is not a hole, but rather a depression resulting from the molding process.)
The defined perimeter of each passage 12 , 14 and 16 at its innermost area at dryer device 1 inner surface is smaller than its defined outermost perimeter at dryer device 1 outer surface. In other words, said passages are defined and configured to broaden or expand in volume from the inner surface to said outer surface of each dryer 1 portion ( 2 , 4 , and 6 ).
At a downstream edge of each passage 12 , 14 and 16 is a fillet surface 22 formed to define the expanding volume. (Fillets 22 blend with smooth downstream edges of each passage so as to further avoid snagging engagement with items being dried.) Volume expansion of passages 12 , 14 and 16 and the attendant reduction of air pressure toward the outside surface of the device 1 serves to foster escape of the moving air from inside to outside of the device 1 . As the moving air progresses through device 1 and outwardly through passages 12 , 14 , 16 and 18 , it impinges against the damp interior confines of a clothing item.
As mentioned above, the overall shape of dryer device 1 presents a distinct advantage when mounting a damp item thereon. As the item and dryer device 1 are moved relatively into juxtaposition, the leading smaller portion 6 enters relatively easily into an item interior portion, regardless of the item size or dampened condition.
With further relative movement, the smaller portion 6 works its way deeper into the damp clothing item so as to encourage the item to move relative to dryer 1 shoulder portion 4 and still further onto larger portion 2 . Of course, smaller items (such as an infant's mitten) may not make it beyond initial insertion of smaller portion 6 .
Further, it should be noted that the present invention may be constructed with more than the two portions 2 and 6 discussed above. For example, an additional portion may follow shoulder 4 , and be configured with a tapered step-down to another shoulder joining an even more reduced portion 6 .
Permitting or directing forced air from heating vents (or the air flow resulting from the rising heat flow from radiator units) into the larger end portion 2 of the inventive drying device 1 facilitates a safe, efficient and effective drying process—progressing from clothing item inside toward item outside. The device is configured to accept a range of apparel sizes from infant to adult. Further, there is no power consumption issue or danger of ignition or electrical short from passive device 1 .
Advantageously, dryer device 1 further includes a vent-connection feature in the form of utility extension 8 having a connector element 9 , and a stabilizing extension tab 10 . Connector element 9 and tab 10 are located generally adjacent opening 20 of the larger portion 2 , and each could take any of a variety of equivalent configurations. In operation, dryer device 1 , with its mounted clothing item may be placed upon an air vent outlet such that extension connector 9 releasably attaches to a portion of vent structure (e.g., vent flow control lever or vent slot).
If needed for device 1 stabilization, the extension tab 10 may first be wedged or pressed within one of the vent slots and the device 1 subsequently attached via connector 9 . In cases where a facility's air flow vent is substantially horizontal or flat, the two extensions 8 and 10 can serve as “feet” to stabilize the dryer device 1 as it resides upon the vent with its smaller portion 6 extending upwardly. Tab 10 may further serve as a labeling point to associate the clothing items (e.g., ski gloves) with their owner.
Words and expressions employed herein are used as terms of description, not of limitation. There is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof. It is to be recognized, therefore, that various modifications are possible within the scope and spirit of the invention. Accordingly, the invention incorporates variations that fall within the scope of the following claims.
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A portable, free-standing dryer device with generally tapered portions formed about a generally central axis facilitating insertion into clothing items to be dried from inside, for example gloves, mittens, socks and other substantially tubular items. The device has a connector temporarily fastening it to a forced air vent. The dryer device comprises at least first and second drier portions joined by an intermediate shoulder portion, each of which defines multiple air passages widening from inner to outer surfaces of the portions to define an expansion volume fostering air flow. A larger substantially open end in the first portion receives air from the vent. The air flows from within the drier outwardly through the passages. An angular relationship of outer surfaces of the first, second and intermediate portions relative to the device central axis ensures that the second drier portion has an extended, narrowing configuration facilitating its insertion into clothing items.
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BACKGROUND OF THE INVENTION
This invention relates to a perform of novel configuration and relates, more particularly, to a preform having an improved structure that is readily adaptable for forming a container made by solid state pressure techniques. The preform is further characterized by being so contoured to present a predetermined volume of polymeric material so that there is maintained not only a uniform distribution of polymeric material during container formation but that there is sufficient polymeric material to meet the dimensional requirements of the desired container.
DESCRIPTION OF THE PRIOR ART
The subject invention is an improvement over prior art preform configurations. It is well known that preforms can be injection molded from a molten polymeric material and later thermoformed into thermoplastic containers. Moreover, the forming of oriented or multilayered preforms is not readily and easily done via injection molding processes, and relatively expensive equipment may be required. Solid state forming has recently been introduced to overcome a number of these limitations.
Solid state pressure forming is a special process used to form oriented, high strength plastic containers, especially multilayered thermoplastic containers whereby barrier or gas impermeable layers may be incorporated. In general, a container is produced by forming a circular preform from a plastic chip or blank by forging the blank and immediately thereafter thermoforming the circular preform into the finished container. During the forging operation where the blank is forged into the circular preform the rim area of the final container is established and held by a gripping fixture that acts to clamp the preform in place along the rim area while the central area or ungripped area of the preform is maintained at a predetermined temperature for the subsequent molding or thermoforming operation. In thermoforming it is important that a predetermined volume of polymeric material be utilized since insufficient or excessive polymeric material would not form a properly dimensioned container. While the preform is maintained at a fixed temperature it is deformed by forcing a plunger through the unclamped portion resulting in the drawing of the polymeric material of a strictly defined volume so that the plunger forms the sidewalls and bottom wall of the container as the plunger travels therethrough of precise dimensions.
Plastic containers may be fabricated from a preform structure of the present invention by molding process such as solid state pressure technique. In a process set forth in U.S. Pat. No. 4,005,967 to Ayres, et al., a preform is forged with a finished rim and immediately thermoformed into a container. In particular, a determined amount of thermoplastic material, such as relatively thin thermoplastic blank, is formed by cutting a sheet of plastic into a plurality of polygonal blanks having a fixed size and shape. The blank is thereafter lubricated or the molds are lubricated in which the blank is to be forged. The blank is preheated to a temperature ranging from just below the softening point to about the melting point of the plastic resin and immediately forged in a heated mold into a circular shaped preform in which the center portion thereof is maintained at its forming temperature while the peripheral rim portion is quickly brought below the softening point of the plastic. The circular preform is thereafter thermoformed into a container having a desired shape.
It is in this thermoforming or molding step that the circular preform must be thoroughly secured so that no edge portion slips or leaves the gripping fixtures, resulting in defects or blemishes in the finished container. When containers are made from preforms of the subject invention, they are of improved quality and have excellent rim or flange structures that are very suitable for seaming to closures and the like.
In the aforementioned patent to Ayers, et al., several holding or retaining means are suggested for securing the preform during the molding process so that there is no pullout from the forming fixture. A number of difficulties have been experienced with these securing means. It has been found that angled barbs suggested for securing the preform are entirely unsuited to fully retain the peripheral part of the preform and as a result certain portions of the preform may slip out of the fixture due to the high forces needed in solid state pressure technique for multilayered structures. Moreover, the suggested holding means often collect a buildup of polymeric material in the recessed molding surfaces which present some difficulty in gripping preforms. Also, because of the location of the holding means being in the flange or rim area itself there has been a problem experienced in properly interlocking the flange to a closure in subsequent double seaming operations.
The process of making a sheet having a plurality of layers is well-known and described by a number of patents, including U.S. Pat. No. 3,476,627 to Squires; U.S. Pat. No. 3,479,425 to Lafevre; U.S. Pat. No. 3,557,265 to Chisholm, et al; and U.S. Pat. No. 3,959,431 to Nissel. The process of making forged preform is disclosed in U.S. Pat. Nos. 3,739,052; 3,947,204; 3,995,763 and 4,005,967 to Ayres, et al; U.S. Pat. No. 4,014,970 to Jahnle; and U.S. Pat. No. 3,757,718 to Johnson. A number of patents disclose various preform configurations that are useful for making plastic containers and include U.S. Pat. No. 3,184,524 to Whiteford; U.S. Pat. No. 3,298,893 and 3,341,644 to Allen; U.S. Pat. No. 3,471,896 to Ninneman; and U.S. Pat. Nos. 3,488,805 and 3,634,182 to Biglin, et al, as well as U.S. Pat. No. 4,286,000 to Dye, et al.
SUMMARY OF THE INVENTION
The subject invention relates to a preform configuration for making an open mouth container, said preform being substantially circular and having a central area for forming the bottom of the container, said preform having an annular sidewall forming portion for the container surrounding and integral with the outer periphery of the central area, a flange connected radially outwardly of said annular sidewall forming portion, said flange having the contour of essentially the rim portion of said container, and a retaining member integral with said flange and extending radially outwardly therefrom, said retaining member having an enlarged cross-sectional configuration as compared to the flange.
The subject invention further relates to the field in solid state pressure forming to a method of gauging a predetermined amount of polymeric material for a preform, the method which comprises providing a polymeric tabular form having a slightly larger volume than a predetermined preform configuration, forging said tabular form into a preform having the predetermined configuration whereby the preform has the necessary polymeric material within its container-forming area to meet the dimensional requirements of the container and allowing the excess polymeric material to be forced outwardly into a peripheral zone to provide an enlarged portion, said zone providing a retaining surface for said preform during the pressure forming of said container.
The present invention was developed to provide an improved preform configuration that presents to the molding surfaces a precise and predetermined volume of polymeric material to achieve dimensional requirements for a given container. Moreover, the subject preform provides an improved configuration that is readily held and secured during the molding step of the solid state forming process for fabricating plastic containers.
Accordingly, a primary object of the subject invention therefore, is to provide a simple and practical means by which a preform may be secured while being thermoformed into a container, the container meeting predetermined dimensional requirements.
Another object of this invention is to provide the in art with a preform characterized by being so contoured to present a predetermined volume of polymeric material in a solid state forming process.
Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings discloses preferred embodiments thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic, cross-sectional view of a forging press showing in place a plastic blank prior to forging;
FIG. 2 is a similar view to FIG. 1 showing the relationship of parts after the blank is forged into a preform in accordance with this invention;
FIG. 3 is the first of a series of section views showing a method for molding the preform herein disclosed into a container, the preform being positioned between a pair of gripping members with die members associated therewith in a molding chamber prior to initiation of the molding operation;
FIG. 4 depicts the die members fully advanced within the molding chamber to form a container from the preform;
FIG. 5 illustrates the separation of the die members after fabrication of the container and immediately before ejection of the container from the molding chamber;
FIG. 6 is an enlarged sectional view showing the desired configuration of the preform of the subjection invention;
FIG. 7 is also an enlarged sectional view like FIG. 6 but having a layered structure therethrough; and
FIG. 8 is an isometric view of the preform in accordance with this invention.
DETAILED DESCRIPTION
Referring now to the drawings and, in particular, to FIGS. 1 and 2, a forging press 10 is shown having an upper ram 11 and a lower stationary ram 12. The press 10 depicts one of the apparatus that can be used to make a plastic preform in accordance with the dimensions and design of the subject invention. The upper ram 11 may be guided by any conventional means (not shown) for reciprocation. It will be noted that the upper ram 11 is provided with an upper platen 13 integrally affixed to the ram 11 and, in a like manner, the lower stationary ram 12 is provided with a lower platen 14. Affixed to the lower platen 14 is a forming fixture 15. Although not shown in the drawings the upper and lower platens 13 and 14, respectively, are provided with conventional heating means such as steam or hot fluid-carrying channels therein. Further, the forming fixture 15 is provided with a cooling means (not shown) such as a separate conduit and circumferential channels within the fixture 15 to transport a cooling liquid therethrough.
The forming fixture 15 comprises a first clamping ring 16 and a second clamping ring 17. As for the first clamping ring 16, it is contoured at 18 to match an upper chamfered surface 18 of upper platen 13 and, in a like manner, the second clamping ring 17 is chamfered to match a lower chamfered surface 19 of the lower platen 14. Both the first and second clamping rings 16 and 17, respectively, are provided with conventional circumferential cooling channels (not shown) as previously mentioned. The first clamping ring 16 is provided with a first shoulder 21; the second clamping ring 17 is likewise provided with a second shoulder 22, said shoulders providing a rim forming portion 31 for a preform 20. Radially outward from the rim forming portion is a retaining area 26, an enlarged portion communicating with the rim portion.
FIG. 2 illustrates the forging operation whereby a plastic blank 25 is formed into the preform 20. The plastic blank 25 is converted into preform 20 within the cavity 30 defined between platens 13 and 14, the flow of the plastic material after filling the cavity 30 being outwardly towards a retaining area 26. In this manner plastic material is forced into the area 26 whereby a specific volume is retained and established for the central portion A of the preform, said portion A being substantially the container-forming portion. It will be now appreciated that retaining area 26 acts to collect a certain amount of residual plastic material upon forging of the preform to thereby insure that a precise volume is retained in the central, container-forming portion A of the preform. It can also be appreciated that the plastic material forces outwardly and into the retaining area excess polymeric material that accumulates and thereby is secured to the outer area of the forming fixture 15. In this way the preform is secured to the fixture and cannot be readily pulled away from forming fixture 15 until released by the same by opening the clamping rings 16 and 17.
In preparation for the thermoforming step the platens 14 and 13 are withdrawn from the forming fixture 15 and the forming fixture 15 comprising the clamping rings 16 and 17 having the preform contained therein is then moved at once to a molding apparatus 33 wherein the molding operation is carried out by thermoforming the preform into the shape of the desired container. FIGS. 3, 4 and 5 illustrate the preform 20 being positioned into alignment with die members comprising upper plunger 32 and mold cavity 34. In particular, the upper plunger 32 is provided with a sealing member 35 which seals itself into clamping ring 16. FIG. 4 shows the member 35 advancing into the mold cavity 34 and the clamping ring 16 engaging the sealing member 35 whereby the preform 20 is stretched over the molding surface B of plunger 32 and air and vacuum means bring the preform into engagement with the base C of the mold cavity 34.
The particular configuration of the subject invention allows a multilayered profile having a precise volume to be thermoformed into a given container design. This follows from the novel structure of the preform itself in that all of the layers transverse the preform so formed and extend outermost to the extremes of the retaining section of the preform. This is of particular importance in multilayered structures wherein one layer may have a relatively slower flow rate in advancing outwardly during the forging operation. For example, certain polymers such as polyvinylidene chloride during the forging step have a somewhat slower flow rate as compared to polyolefins like polypropylene and as a result the polyolefin advances ahead to fill the outer confines of the preform cavity thereby blocking or interfering with the advance of the slower moving polyvinylidene chloride. It is of particular importance that such blockage not occur, especially in the rim forming portion of the preform. The subject invention therefore provides a means to allow such slower moving polymers to extend outwardly beyond the rim forming portion of the preform.
Although the forging temperature is a relative term it cannot be specifically defined without considering the properties of each polymer. For a given polymeric material, optimum forging temperature can be determined in accordance with this invention. The pressure ranges used in the forging step are quite variable according to the plastic which is to be forged and to the temperature to which it is heated and to the dimensions of the cavity of the mold. The blank 25 is generally lubricated and preheated to a temperature ranging just above the softening point to below the melting point of the material, and then placed on the lower platen 14. The upper ram 11 then is allowed to descend under pressure to forge the heated blank 25 into the cavity between the platens 13 and 14 in a cavity configuration to form preforms as shown in FIGS. 6, 7 and 8. The upper and lower platens 13 and 14 are heated to a forging temperature, generally above the softening point of the material being forged. The temperature of the platens and the blank can be the same or different but it is preferred to have the platens at a slightly higher temperature than the blank. A preform made in accordance with this invention can be most readily thermoformed into an open-mouth container having uniform sidewalls and structural integrity.
The invention may be constructed of various materials. In particular, the invention is applicable to the use of a single plastic such as polyolefin, including polyethylene, polypropylene, etc., and polyvinyl aromatics such as polyesters, polystyrenes as well as polyvinyl halides such as polyvinyl chlorides. Moreover, an essential aspect of the subject invention is the structural features of the preform itself, in that it readily is formable into multilayered articles, including open-mouth containers. For example, a multilayer material may consist of polyvinyl aromatics such as styrene, polyvinyl toluene, or rubber modified blends thereof with a core 36 of polyvinylidene chloride. A further useful layer may consist of polyethylene or polypropylene with a core of polyvinylidene chloride. Containers formed with a polyvinylidene chloride layer are excellent barriers to gases such as oxygen and carbon dioxide.
It will be appreciated from the polymeric materials used and the conditions under which the preform is formed that a considerable degree of orientation is built into a given container through the forging of the preform. In a like manner when a preform is forged below the softening point of a blank, a high degree of orientation is formed in the container.
The embodiments of this invention disclosed in the drawings and specification are for illustrative purposes only, and it is to be expressly understood that said drawing and specification are not to be construed as a definition of the limits or scope of the invention, reference being made to the appended claims for that purpose.
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A multilayered preform is disclosed for making an open mouth container. The preform has a container-forming portion comprising a circular central area for making the bottom of the container, an annular sidewall-forming portion for the container surrounding add integral with the outer periphery of the central area, a flange connected to the annular portion, said flange having the contour of the rim of the container, said container-forming portion having a predetermined volume to meet dimensional requirements, and a retaining member having an enlarged portion. The preform is an improved structure that is readily adaptable for making containers from the so-called solid state pressure forming process.
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DEDICATORY CLAUSE
The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalties thereon.
BACKGROUND OF THE INVENTION
In a control system, actuators driven by hydraulic or pneumatic fluids might be used. As an example, a pneumatic actuator in a guided missile may be employed to move air vane control surfaces, or jet vane control surfaces, or swivel nozzles. A valve, such as a solenoid ball valve, controls the fluid flow to the actuator control chamber for work on the large area piston of a dual piston design or the large area, low pressure side of a single piston. The solenoid ball valve used for this purpose may be either an opened center valve or a closed center valve.
The opened center valve design has a large, constant gas flow rate. In a typical missile system the opened center valve design requires only one solenoid valve per actuator, whereas the closed center valve design requires two solenoids. However, the closed center valve requires much less gas to operate in a typical duty cycle of operation. The closed center valve has a performance deadzone causing some small signal performance degradation. The only gas flow requirement for the closed center valve is during piston displacement. Consequently, there is a trade-off in choosing between the valve system performances and the amounts of actuating fluid used during performance. Design requirements for use of such valve systems in guided missiles accentuate a need to minimize actuating fluid mass and storage volume.
SUMMARY OF THE INVENTION
A dual rate actuator which employs two solenoid valves coupled in series in such a way that dual flow rate capability is provided to a missile control system actuator. A first solenoid valve determines the fluid flow direction through the actuator body to control piston movement in two directions to displace control devices of a missile. The second solenoid valve determines the fluid flow through a choice of effective orifices in the actuator body, which regulates the fluid flow rate for a given working pressure.
DESCRIPTION OF THE DRAWING
The single FIGURE is a sectional view of an embodiment of the dual rate actuator.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, the single FIGURE discloses a missile control vane actuator representative of a control actuator which incorporates solenoid controlled ball valves providing dual rate control of a fluid motor.
Typically, actuator 10 is comprised of a control chamber 12, which is divided into upper control chamber 12a and lower control chamber 12b by piston 14. Piston 14 has upper piston surface 16 and lower piston surface 18, the former's area being greater than the latter's area. Piston 14 is connected through piston rod 20 to a control device. Actuator 10 is also comprised of solenoid actuated ball poppet valves 22 and 30. Solenoid actuated ball poppet valve 22 is comprised of valve chamber 24, poppet ball 26 and solenoid 28. Solenoid actuated ball poppet valve 30 is comprised of valve chamber 32, poppet ball 34 and soleniod 36. Actuator 10 has outlet passage 38, which is connected to valve chamber 32, and inlet passage 40, which is connected to a pressurized fluid source. Actuator 10 also has a plurality of passages numbered 42, 44, 46, 48, 50 and 52. Inlet passage 40 branches into passage 42, which connects to lower control chamber 12b, and passage 44, which connects to valve chamber 32. Passage 46 connects to valve chamber 32 and branches into passages 48 and 50, both of which connect to valve chamber 24. Orifices 54 and 56, located in passages 48 and 50 respectively, are of different effective crosssectional areas thereby permitting coarse and vernier adjustment to fluid flow. Passage 52 connects valve chamber 24 and upper control chamber 12a.
When solenoid actuated ball poppet valve 30 is not energized, poppet ball 34 closes the connection between passage 38 and valve chamber 32, thereby permitting fluid flow from passage 44 through valve chamber 32 into passages 46, or conversely. When solenoid actuated poppet ball valve 30 is energized, poppet ball 34 closes the connection between valve chamber 32 and passage 44, permitting flow from passage 46 through valve chamber 32 into passage 38, or conversely.
Similarly, when solenoid actuated ball poppet valve 22 is not energized, poppet ball 26 closes the connection between valve chamber 24 and passage 50, thereby permitting fluid flow from passage 48 through valve chamber 24 into passage 52, or conversely. When solenoid actuated ball poppet valve 22 is energized, poppet valve 26 closes the connection between valve chamber 24 and passage 48, permitting fluid flow from passage 50 through valve chamber 24 into passage 52, or conversely.
During operation, fluid is delivered from a pressurized fluid source through passages 40 and 42 into lower control chamber 12b, pressuring lower piston surface 18. Depending on the energization state of solenoid 36, either fluid also flows from the pressurized fluid source through valve chambers 32 and 24 and various connecting passages to upper control chamber 12a or fluid flows from upper control chamber 12a through valve chamber 24 and 32 and various connecting passages to passage 38 to exhaust, effecting in either case a pressure on upper control surface 16. The speed of this fluid flow is governed by the energization state of solenoid 28. When solenoid 28 is unenergized, poppet ball 26 closes passage 50 and fluid flow is through orifice 54. When solenoid 28 is energized, poppet ball 26 closes passage 48 and fluid flow is through orifice 56.
Movement of piston 14 is effected by the pressure forces on upper piston surface 16 and lower piston surface 18. The force transmitted by piston 14 and piston rod 20 outputs a driving force to a load circuit, such as a crank arm connected to a missile control device, e.g., an air vane control surface. Typically, sensors (not shown) are used to determine the error in the missile control device. An error signal is coupled from the sensor to a controller (not shown). The controller, in accord with a predetermined control strategy, then directs movement of the actuator piston 14 and piston rod 20 to reduce or eliminate the existing error. The direction of piston 14 movement is controlled by the controller input signal to solenoid 36 and the speed of movement is controlled by the input signal to solenoid 28. The control strategy is processed so that when the magnitude of error exceeds a predetermined maximum, fluid flow will be through the larger of orifice 54 and orifice 56. When error magnitude is less than the maximum, flow is through the smaller vernier orifice. Also, when the error is at zero, there will be no loss of pressurized fluid through passage 38. Thus, the dual rate actuator provides output correctional signals while using a relatively small loss of fluid.
Although the present invention has been described with reference to the 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 foregoing disclosure. Accordingly, the scope of the invention should be limited only by the claims appended hereto.
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Two solenoid controlled ball valves are employed in such a way that dual w rate control is provided to a missile control vane actuator. The result is the superior performance of an open center valve actuator over that of a closed center valve actuator with gas consumption savings approaching that of the closed center valve design and having the same complexity as a closed center design.
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TECHNICAL FIELD
The present invention relates to the use of crushed and graded ore, preferably magnetite ore, for manufacturing moulds and cores (i.e., mould elements) for use in casting non-ferrous metals or alloys, especially light metals and light-metal alloys.
Magnetite is a ferromagnetic mineral with the stoichio-metric composition Fe 3 O 4 . In the present context, the expression "graded" is used to indicate that the ore, after having been crushed, has been subjected to a certain particle-size sorting, e.g. by screening, air separation or flotation, as it is well-known for particulate materials such as sand.
BACKGROUND ART
Up to the present, the particulate mineral base material used for manufacturing moulds and cores has practically exclusively been quartz sand.
Admittedly, it is not unknown within the foundry industry also to use other particulate mineral base materials such as olivine sand, a magnesium-iron silicate, and zircon sand, a zirconium silicate. Due to their high resistance to heat and their high price, these base materials have especially found localized use as so-called "pattern sand" or as a core inlay in such regions of moulds for casting steel castings that are particularly exposed to heat, so as to avoid or reduce the "burning-on" of sand on corresponding regions of the castings and the consequent cumbersome and costly cleaning of the castings.
A corresponding use has been found for crushed chromite ore, as with this mineral it is also the case that its wetting relations towards liquid steel are such, that it simply "repels" the latter.
No examples are known of such particulate mineral base materials having been used in a larger mass of circulating mould material, let alone for casting non-ferrous metals or alloys.
In a paper (38th International Foundry Congress, Exchange Paper No. 9, Dusseldorf, 1971) "Moglichkeiten der industriellen Anwendung des Magnetformverfahrens zur Herstellung von Massengussteilen" by A. Wittmoser, K. Steinack and R. Hofman, mass production of castings is described, based on a mass production of heat-gasifiable patterns of expanded polystyrene foam. These patterns are covered by being sprayed with or dipped into a coating (Schlichte), after which they are enveloped with a flowable mixture of iron granulate and crushed magnetite ore, possibly in a fluidized state. Prior to the casting operation, a magnetic field is applied to the mould material so as to bond its individual particles together magnetically, said field being maintained during the casting proper and at least a part of the time, during which the metal solidifies in the mould. When the magnetic field has been removed, the mould material, now again being flowable, flows away from the casting, after which it may be used in new moulds, possibly after having been cooled. The paper, exclusively relating, to the casting of ferrous alloys, mentions the higher cooling effect of the mould material as compared to quartz sand, and also discusses how this cooling effect may be varied by changing the quantitative ratio between iron granulate and magnetite particles in the mould material, so that an increased proportion of magnetite particles reduces the cooling effect.
Obviously, this method cannot be used in a conventional moulding and casting system.
For casting light-metal castings, especially for use in the automotive and similar industries, there is, however, a great need for achieving a more rapid cooling of the metal having been cast in the mould, as this makes it possible to achieve a more fine-grained structure in the casting and also to avoid so-called micro-contraction cavities in the castings.
At the present time, attempts are made to achieve such more rapid cooling by casting in so-called metallic moulds (dies). Such moulds are, however, costly to manufacture, and in comparison with casting in a conventional moulding and casting system based on the use of sand, their productive capacity is very limited.
DISCLOSURE OF THE INVENTION
It is the object of the present invention to show how it is possible, in a conventional moulding and casting plant based on the use of sand, to achieve rates of cooling approximating those that can be achieved in metallic moulds.
According to the present invention, this object is achieved by the use of a crushed and graded ore, preferably magnetite ore, as a particulate mineral base material in a recyclable or non-recyclable mould or core material, respectively, for manufacturing dry or green, preferably clay-bonded, especially bentonite-bonded, in-box moulds or boxless moulds, and cores for placing in such moulds or in metallic moulds (dies), preferably when casting non-ferrous metals or alloys, especially light metals and light-metal alloys.
Compared to the use of quartz sand as base material, this primarily means that the metal having been cast in the moulds solidifies more rapidly, and that the castings, especially light-metal castings, in this process are given a more fine-grained and "denser" structure, approximately corresponding to what can be achieved by die casting. I.e., that in a conventional moulding and casting system based on the use of moulding sand, and with the relatively low pattern costs and high productive capacity associated with such plants, it is possible to achieve a quality in the castings at least approximately on the level with what can be achieved by using die-casting systems with considerably higher mould costs and lower operating rate.
A second advantage is that with the use according to the invention, it is possible to make the cooling section of a moulding and casting system substantially shorter, thus saving space.
A third advantage is that the quantity of moulding material being recycled can be reduced in comparison to the use of quartz sand as base material, thus partly compensating for the use of the--after all--costlier base material.
A fourth advantage pointing in the same direction may be seen from the following: For environmental reasons, it is relatively costly to store or deposit used and discarded mould material based on quartz sand, but in the case of discarded mould material based on magnetite ore, it is not only possible to dispose of this free of charge, but possibly even also with an economic advantage, as this material may, without further processing, be utilized for producing iron, not only in blast furnaces, but in practically any furnace for melting iron or steel.
Yet another advantage with the use of magnetite ore as base material is that this material, in contrast to quartz sand, cannot give rise to the occurrence of the pulmonary disease silicosis.
An advantage of using this material for cores to be placed in metallic dies is that, in contrast to metal cores, such cores may be shaped in any desired manner and still have a substantially greater cooling capability than a corresponding core of quartz sand.
With the use according to the invention it has proved advantageous that the base material has a particle-size distribution mainly in the interval of 0.05 mm to 0.5 mm, preferably in the interval of 0.1 to 0.25 mm, and mainly lying within three standard mesh screens.
The mould material used for the moulds may advantageously be clay-bonded wet mould material produced by mixing the base material with preferably 2-20% by weight of bentonite, preferably 1-5% by weight of water and optionally preferably 1-10% by weight of additives. The bentonite being used preferably being a naturally occurring Na-bentonite (western bentonite) or a so-called "active bentonite", i.e. a Ca-bentonite (southern type) having been converted to Na-bentonite by ion exchange. Bentonite is a commonly used bonding agent in the foundry industry.
Alternatively, the mould material may be produced by mixing the base material with preferably 5-10% by weight of cement, preferably 1-5% by weight of water and optionally 1-10% by weight of additives. In both cases the moulds may, have been dried up to a temperature of approximately 400° C. prior to the casting, have been dried prior to the casting.
As a second or further alternative, the mould material may have been produced by mixing the base material with preferably 5-10% by weight of water glass and optionally 1-10% by weight of additives, and if so, the moulds may have been made to set or harden prior to casting by being blown through by CO 2 .
In all three cases, the additives are preferably chosen from the group comprising coal dust, cereals and ground wood, but this does not exclude the use of other additives.
With the use according to the invention, the cores preferably consist of a core material produced by mixing the base material with a bonding agent chosen from the group comprising settble and self-setting organic or inorganic core-bonding agents in solid or liquid form, possible know per se, the core material possibly having been hardened or made to set by heating or by being blown through with a gaseous hardening or setting agent.
The cores may, however, also be composed of clay-bonded wet core material with a composition as noted above and hardened or made to set by freezing, the refrigeration of the core boxes e.g. being achieved by using a gas, such as nitrogen. In this manner, the core will produce an extra strong cooling effect, that may be desirable for certain applications, e.g. the afore-mentioned use of the core in metallic moulds.
Preferably, a part of the mould and core material arising from the shake-out operation is reworked to form mould material by mixing with a suitable percentage by weight of water and optionally with a suitable percentage by weight of argillaceous bonding agent, whilst in this case, the addition of water and bonding clay is preferably attuned in such a manner, that the moulding material being recirculated will have the desired moulding properties.
The remainder of the mould and core material arising from the shake-out operation may be subjected to a regeneration and re-use as a base material as noted above, it being possible with such a regeneration process to use methods and apparatuses well-known for similar treatment of mould and core material based on quartz sand, but in addition supplemented with a magnetic separation, due to the magnetic properties of the base material.
Alternatively, the base material in the part not having been reworked may be utilized in a metallurgical process for producing a metal. This means that the surplus quantity of used moulding material does not have to be stored or deposited at great cost as in the case of quartz sand as base material, but may profitably be utilized in metal-winning processes--in the case of magnetite, this may be carried out in conventional iron or steel casting furnaces or in iron-melting furnaces, optionally with a prior pelletization of the magnetite material.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following part of the present description, the invention will be explained in more detail, i.a. on the basis of comparative examples of moulding material based on crushed and graded magnetite ore and based on quartz sand, respectively.
In the "technological" trials discussed below, the commonly used sand-testing equipment from the firm of Georg Fischer A. G., Schaffhausen, Switzerland, has been used, and the testing instructions given by this firm have been followed.
A parameter exhibiting a decisive difference between the magnetite sand and the quartz sand being used is the weight per unit volume of the dry base sand, i.e. the weight of e.g. one liter consolidated sand in kilogrammes, for magnetite sand amounting to approx. 2.8 and for quartz sand approx. 1.5. Further, the cooling effect of magnetite sand amounts to approx. 1500 J/m 2 s 1/2 ° K. as against approx. 1000 J/m 2 s 1/2 ° K. for quartz sand.
For use in comparative tests, the following mixtures were produced in a laboratory mixer:
I. MAGNETITE SAND: 4.5 kg of magnetite sand was mixed for 7 minutes with 300 g of active bentonite ("Geko"®) and 63 g of water, after screening being subjected to the tests indicated in Table 1.
II. QUARTZ SAND: 2.5 kg of quartz sand was mixed for 7 minutes with 300 g of active bentonite ("Geko"®) and 63 g of water, after screening being subjected to the tests indicated in Table 1.
TABLE 1______________________________________ Magnetite sand Quartz sand______________________________________Weight of standard 250 146test sample50 mm × 50 mm diam.Compression strength 1250 1600p/cm.sup.2Shear strength 230 300p/cm.sup.2Gas permeability 60 120______________________________________
Test moulds with the dimensions 36 mm dia.×185 mm were produced using the same pattern and the mould-sand mixtures described in I and II above, said test moulds being cast with AlSi7Mg at 680° C. At the same time test pieces of corresponding dimensions were cast in a metal mould, and the following parameters were determined:
DAS, i.e. dendrite arm spacings in μm
t s , i.e. solidification time, in seconds
TABLE 2______________________________________Metal moulds Magnetite sand Quartz sand______________________________________DAS 36 38 44t.sub.s 47 55 85______________________________________
These figures show quite clearly the greater cooling effect of the magnetite sand as compared to quartz sand, while the micro-structure of the samples cast in magnetite-sand moulds was approx. 13.6% "denser" (more "fine-grained") than in samples cast in quartz-sand moulds, their solidification time being reduced by approx. 35% compared to that for samples cast in quartz-sand moulds. It can also be seen that for both parameters mentioned, values are achieved approximating those achieved by casting in a metal mould.
In addition to the uses described above, it would be near at hand for a person skilled in this art to use cores as described above in moulds having quartz sand as base material, so as to achieve both the associated improved cooling effect and the reduced force of buoyancy of the cores after casting of the mould. In that case, the magnetite sand may easily be separated magnetically from the quartz sand after shake-out, thus partly recovering the magnetite sand, partly avoiding contamination of the circulating quartz sand with core sand and core-bonding agents.
In the above description, the use according to the invention tion has been described in connection with the casting of light-metal alloys, but it will be understood that said use may also be carried out when casting e.g. non-ferrous copper alloys or even ferrous metals, such as cast iron.
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Crushed and graded magnetite ore is mixed with clay to form foundry moulds and cores. These moulds or cores are useful when casting non-ferrous metals or alloys, especially light metals and light-metal alloys.
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TECHNICAL FIELD
[0001] The present disclosure relates generally to laminated composites and methods of making the same, and more particularly to laminated composites made with prepregs and fiber veils having nanofibers attached thereto.
BACKGROUND
[0002] Laminated composites made with carbon fiber-epoxy prepregs have been used for many applications. Enhanced impact properties of such laminated composites may be particularly desirable for certain automotive and engineering applications. Efforts to improve the impact properties of laminated composites include modifying the matrix resin properties or the laminate structure. The former is accomplished primarily by toughening the prepreg resin system utilizing appropriate toughening materials. The latter has been attempted by incorporating various interfaces between layers using smaller scale fibers.
SUMMARY
[0003] The instant disclosure relates to a laminated composite and methods of making the same. The laminated composite includes a plurality of stacked prepregs having an interface formed between each pair of adjacent prepregs. Each prepreg includes a matrix material and reinforcing fibers dispersed therein. The laminated composite also includes at least one fibrous veil laminated to at least a portion of at least one of the interfaces, the at least one fibrous veil having nanofibers attached to at least one surface thereof. Also disclosed herein are a fibrous veil and a method of making the nanofiber-doped fibrous veil.
BRIEF DESCRIPTION OF THE DRAWING
[0004] Features and advantages of the present disclosure will become apparent by reference to the following detailed description and drawings.
[0005] FIG. 1 is a graph of comparative displacement curves plotting Load (kN) vs. Displacement (mm) from a sample of the laminated composite disclosed herein and multiple comparative samples; and
[0006] FIGS. 2A , 2 B and 2 C are a series of three schematic diagrams illustrating the steps of dispersing carbon nanofibers (labeled “CNF Dispersing” in FIG. 2A ), doping a veil with carbon nanofibers (labeled “CNF Doping” in FIG. 2B ), and performing laminate molding (labeled “Laminate Molding” in FIG. 2C ).
DETAILED DESCRIPTION
[0007] The laminated composite disclosed herein exhibits superior impact properties when compared to other known laminated composites. The composite of the examples disclosed herein includes small amounts of nanofibers strategically placed at the interfaces between multiple prepreg layers. These small amounts of nanofibers are attached to thin fibrous veils, which are used as carriers for the nanofibers. These thin fibrous veils carrying the nanofibers are placed at the interfaces between the prepreg layers. The nanofiber-doped fibrous veils advantageously increase the impact properties of the resulting composite, without substantially increasing the thickness of the composite.
[0008] The term “prepreg”, as used herein, is a combination of matrix resin and fiber reinforcement which is ready for use in the manufacturing process disclosed herein under heat and pressure. In one example, the fibers of the prepreg have been impregnated with a pre-catalyzed matrix resin and partially cured (B-stage). A “lay-up” refers to the procedure of laying the prepreg, which has been pre-impregnated with the resin, outside or sometimes directly onto the mold. It is to be understood that in the method disclosed herein, the lay-up procedures also involve laying the nanofiber-doped veil (discussed further hereinbelow) between the prepregs.
[0009] In preparing the laminated composite disclosed herein, the lamination of the nanofiber-doped veils onto the prepregs takes place during the lay-up process. One advantage of this technique is that it does not require any chemical or physical modifications of the existing prepregs. Modifying commercial prepregs is generally difficult and costly, at least in part because these materials are delicately balanced in their cure rate, viscosity-temperature behavior, and handling characteristics. It is to be understood that the method of making the laminated composite disclosed herein may be used with any prepreg. The technique is believed to be practical for implementation since it requires minimal, if any, alteration of the conventional prepregs and/or of the lay-up processes.
[0010] Another advantage of the method disclosed herein is that it uses a significantly smaller amount of the nanofibers, compared with the traditional methods of incorporating nanofibers into the entire prepreg resin matrix. For example, a previous study found in literature (see FIG. 12 in Quaresimin et al., “Understanding the effect of nano-modifier addition upon the properties of fibre reinforced laminates,” Composites Science and Technology, Volume 68, Issues 3-4, March 2008, Pages 718-726) reported a 20% improvement in impact energy by adding 7.5 wt % of carbon nanofibers (CNF) to the prepreg itself. The technique of the present disclosure generates more than 20% improvement with less than 2 wt % of CNF, and without having to incorporate the CNF into the prepreg composition, as shown in Tables 1 and 2 in the examples hereinbelow.
[0011] Still another advantage of the method disclosed herein is that any increases in thickness and weight of the parts molded from the laminated composite resulting from the process disclosed herein are minimal and likely negligible. For example, the thickness of the molded composite may be increased by about 0.01 mm to about 0.1 mm by including the doped veils. Therefore, the method disclosed herein is applicable without having to modify existing part design and manufacturing tooling and processes.
[0012] Generally, as shown in FIG. 2A , the method begins by dispersing a small amount of suitable nanofibers having diameters ranging from about 60 nm to about 200 nm into a desirable solvent or solution. The small amount of nanofibers dispersed in the solvent generally ranges from about 0.5 to about 2 weight percent of nanofibers in the solvent. The amount chosen is such that the nanofibers disperse to achieve the desirable solution, and such that the resulting solution facilitates substantially even distribution of the nanofibers onto the fibrous veil. Furthermore, it is to be understood that the amount of nanofibers used may be varied, depending, at least in part, on the desirable enhanced level of the impact properties.
[0013] Non-limiting examples of suitable nanofibers include oxidized and non-oxidized carbon nanofibers, nanoscale carbon whiskers, polymeric nanofibers, ceramic nanofibers, and metallic nanofibers. Such nanofibers may be pre-grown, synthesized, or spun nanowires; naturally deposited minerals having a nanoscale fiber or tubular structure that are commercially available; or may be fabricated as part of the method disclosed herein (e.g., via vapor growth processes). For example, carbon nanofibers may be grown by catalytic chemical vapor depositions of a range of hydrocarbons (such as methane, ethylene, propane, acetylene, benzene, natural gas, etc.) over a catalyst surface made of metal or metal alloy (such as iron, nickel, gold, cobalt, nickel-copper, iron-nickel, etc.). The vapor growing process is a typical method to produce carbon nanofibers which includes feeding a mixture of hydrocarbon, metal catalyst, and co-catalyst to a gas phase reactor.
[0014] In one example, the total amount of nanofibers in the final molded composite is generally less than 2 wt % of an amount of the total matrix material in the final molded composite. For example, if three doped veils include 2 wt % of the total nanofibers in the composite resin matrix, then each veil contains about 0.7 wt % of nanofibers with respect to the total amount of matrix resin used.
[0015] Since it is desirable that the nanofibers be dispersed in the selected solvent or solution, the solvent/solution selected will depend, at least in part, on the nanofibers being used. In a non-limiting example, isopropyl alcohol is a suitable solvent for dispersing oxidized carbon nanofibers. In another non-limiting example, other solvents that may be used include acetone, dimethylformamide, methanol, and ethanol. In another non-limiting example, isopropyl alcohol, a suitable solvent, a colloidal nanosilica/isopropanol solution, and a suitable dispersant may be mixed together and used as a suitable solution for dispersing non-oxidized carbon nanofibers. It is to be understood that some dispersion aids may also be used with the solvents to assist in dispersing the non-oxidized carbon nanofibers. These dispersion aids may include dimethylsulfoxide, N-methyl-2-pyrrolidone, and TRITON®-X100 (i.e., a nonionic surfactant which has a hydrophilic polyethylene oxide group).
[0016] The dispersion of the nanofibers in the selected solvent/solution may be accomplished by adding the nanofibers to the solvent/solution and exposing the mixture to sonication for a predetermined time. It is to be understood that the sonication time depends, at least in part, on the nanofibers and solvent/solution used. The temperature of the sonication bath is not strictly controlled, but the solution is kept relatively cool to prevent overheating by sonication. Such overheating may lead to rapid evaporation of the solvent and deterioration of the dispersion efficiency. The sonication time is determined, at least in part, by the nanofibers' dispersibility into the solvent or solution selected. The sonication time may also depend upon the maximum duration that the dispersed state may be maintained before phase separation begins.
[0017] Referring now to FIG. 2B , thin fibrous veils are dipped into the nanofiber-dispersed solution, thereby doping the veils with the nanofibers. One non-limiting example of a fibrous veil is a glass, carbon, or polymeric fibrous veil. The veils are allowed to soak for a predetermined time in the nanofiber-dispersed solution such that the nanofibers adhere to one or more exposed surfaces of the veil. The doped veil(s) is/are then dried. Drying can be accomplished by evaporating the solvent for a predetermined time at a predetermined temperature (a non-limiting example of which is room temperature).
[0018] The dried doped veil(s) is/are laminated at an interface between adjacent prepregs using standard lay-up procedures. As previously mentioned, any desirable prepreg may be used. In one example, the prepregs are unidirectional carbon fiber/epoxy prepregs including at most 35 wt % epoxy resin and at least 65 wt % carbon fibers. In terms of fiber structure, prepregs made of woven fabrics (such as plain, satin, twill, etc.), or multi-axial fabrics (such as non-crimp) may be used. Non-limiting examples of suitable prepreg fiber materials include carbon, glass, boron, and polymers. The carbon fibers in the prepregs may be, for example, 12K carbon fibers or 24K carbon fibers. Non-limiting examples of suitable prepreg matrix resins include epoxy resins, phenolic resins, polyester resins, vinyl ester resins, polyimide resins, thermoplastic resins, etc.
[0019] After being laminated together, the prepregs having the doped veil between the interfaces are molded into a composite part, using, for example, compression molding techniques (see, for example, FIG. 2C ). Other non-limiting examples of suitable molding techniques include the vacuum bag process and the autoclave process.
[0020] To recap, in FIGS. 2A through 2C , there are provided schematic drawings of a) CNF being dispersed in alcohol by sonication; b) a fibrous veil being dipped in the CNF dispersion and then dried; and c) CNF doped veils being placed in the interfaces between several layered unidirectional (UD) prepregs, and the UD prepreg/veil structure subsequently being compressed under heat.
[0021] In the examples disclosed herein, the average diameter of the fibers making up the fibrous veils (not to be confused with the attached nanofibers) is the same or similar to the average diameter of the fibers making up the prepregs. In one example, the average diameter of the fibers in the veils and the prepregs ranges from about 7,000 nm to about 9,000 nm. Such fibers are generally commercially available, and, in some instances, may be more desirable. It is to be understood that the fibrous veils may be made with smaller fibers, but, in some instances, such veils may be more difficult to prepare and more costly.
[0022] To further illustrate the example(s) disclosed herein, the following examples are given. It is to be understood that these examples are provided for illustrative purposes and are not to be construed as limiting the scope of the examples disclosed herein.
EXAMPLES
[0023] Molded panel samples were prepared according to the method disclosed herein (some with oxidized nanofibers (Samples 2 and 3) and some with non-oxidized nanofibers (Sample 1)), and two comparative molded panel samples were prepared, one of which included no veils (Comparative Example 1), and the other of which included un-doped veils (Comparative Example 2).
[0024] The sample composites according to the method disclosed herein were made as follows. The nanofibers used were non-oxidized (PR-24-LHT-LD) and oxidized (PR-24-XT-PS-OX) vapor grown carbon nanofibers supplied by Applied Sciences. To prepare the carbon nanofiber (CNF) containing veils, up to 2 g of the oxidized fibers were dispersed into 125 ml to 175 ml of isopropyl alcohol by sonicating for 1 hour in an ice-water cooling bath. The same amount of non-oxidized fibers was used in the same amount of isopropyl alcohol. In order to disperse the non-oxidized CNF in isopropyl alcohol, however, 0.5 g of TRITON®-X100 dispersant by Calbiochem and 0.6 g of IPA-ST colloidal nanosilica/isopropanol solution by Nissan Chemical (30 wt % silica) were added to the isopropyl alcohol before sonicating.
[0025] The dispersed solutions were transferred to respective square basins and fibrous veils (Optimat 20103A (glass fiber, 17 g/m 2 ) supplied by TFP) were dipped into, and then taken out of the respective basins. The wet veils were dried by evaporating the alcohol for about 30 minutes at room temperature. The dry CNF-containing veils were then weighed.
[0026] The unidirectional carbon fiber-epoxy prepregs used in these examples consisted of 35 wt % of resin and 65 wt % of either 12K or 24K T700 carbon fibers, supplied by Patz Materials and Technologies. The aerial weight of the prepregs was 300 g/m 2 .
[0027] Standard lay-up procedures were applied, and the lay-up arrangements were 0/90/0/0/90/0 for Comparative Example 1 and 0/V/90/0/V/0/90/V/0 for samples including veils (V=veil) (Samples 1, 2, 3 and Comparative Example 2). Each of the laid-up composite samples was compression molded in a picture frame (254 mm×254 mm) and two flat plates at 0.4 MPa and 157° C. for 10 minutes. The nominal thickness of the molded panel composites with veils (i.e., Samples 1, 2, 3 and Comparative Example 2) was about 1.85 mm and the nominal thickness of the molded panel composites without veils (i.e., Comparative Example 1) was 1.80 mm. The weight increases caused by adding veils and CNF were less than 2.2 wt % of the composite panels.
[0028] Square specimens (100 mm×100 mm) were then cut from the laminated composite panels for impact testing. The impact tests were performed using a high-rate Instron machine equipped with a hemispherical impact plunger (20 mm in diameter). The impact speed of 0.5 m/sec was selected to provide enough energy to penetrate specimens after preliminary tests. From the load-displacement curve, the maximum load was found and the corresponding energy was calculated by numerical integration under the curve for each sample. The energy to penetration was obtained by integration to the penetration point beyond which the oscillation of the load is still present, but as a representation of hinge effects. The impact testing was videotaped at the back side of the sample using a high speed video camera to confirm the interpretation of the load-displacement curve.
[0029] Three typical load-displacement curves obtained from the impact tests are shown in FIG. 1 . The graph depicts Load (in kilo Newtons) vs. Displacement (in millimeters) for samples without veils (Comparative Example 1), samples with veils alone (Comparative Example 2) and samples with veils having oxidized CNF (1.6%, Sample 3). The numbers used for the Samples and Comparative Examples are averaged from 2 to 3 of the same or similar samples with at least two tests having been performed for each sample. The impact curve for the sample panel without fibrous veils (Comparative Example 1) was adjusted slightly higher to take into account the thickness increase (0.05 mm or 3%) caused by the addition of veils in the other samples. It was found that the addition of CNF onto the veils did not cause any measurable thickness change when compared to Comparative Example 2 (veil without CNF). The data indicates that the overall impact behavior of the samples was not altered by the addition of veils (either with or without CNF). However, the maximum load and impact energy were markedly increased for Comparative Example 2 containing the undoped fibrous veils only and further increased for Sample 3, containing fibrous veils doped with oxidized CNF.
[0030] The improvement in impact properties of the laminated composites including various amounts of CNF is summarized in Tables 1 and 2 (below) in terms of percent increase in maximum load, energy to maximum load, and energy to penetration. The concentration of CNF was calculated as a weight percent of the total resin matrix in the composite samples. The results show that the method disclosed herein successfully achieved significant enhancement in impact properties of laminated composites.
[0000]
TABLE 1
Impact properties of laminated composites (12K, T700 carbon
fiber): Comparative Example 1 with no veils, Comparative Example 2
with veils having no CNF, Sample 1 with veils having non-oxidized CNF
and Samples 2 and 3 with veils having oxidized CNF
Energy to
Energy to
Max. Load
Max. Load
Penetration
CNF in
%
%
%
resin %
kN
increase
J
increase
J
increase
Comparative
0.0
4.0
0
10.9
0
30.6
0
Example 1
Comparative
0.0
5.3
32
19.6
80
41.9
37
Example 2
Sample 1
0.8
5.5
37
25.1
131
47.1
54
Sample 2
0.5
5.9
47
26.2
140
47.9
57
Sample 3
1.6
6.5
63
29.5
170
53.5
75
[0000]
TABLE 2
Impact properties of laminated composites (24K, T700 carbon
fiber): Comparative Example 1 with no veils, Comparative Example 2
with veils having no CNF, Sample 1 with veils having non-oxidized CNF
and Samples 2 and 3 with veils having oxidized CNF
Energy to
Energy to
Max. Load
Max. Load
Penetration
CNF in
%
%
%
resin %
kN
increase
J
increase
J
increase
Comparative
0.0
2.7
0.0
7.4
0.0
19.3
0.0
Example 1
Comparative
0.0
3.7
37
10.3
39
25.1
30
Example 2
Sample 1
1.1
4.4
65
12.0
67
27.6
47
Sample 2
0.8
4.1
55
13.5
87
31.0
65
Sample 3
1.5
3.8
42
11.7
63
30.9
65
[0031] While several examples have been described in detail, it will be apparent to those skilled in the art that the disclosed examples may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.
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The instant disclosure relates to a laminated composite and methods of making the same. The laminated composite includes a plurality of stacked prepregs having an interface formed between each pair of adjacent prepregs. Each prepreg includes a matrix material and reinforcing fibers dispersed therein. The laminated composite also includes at least one fibrous veil laminated to at least a portion of at least one of the interfaces, the at least one fibrous veil having nanofibers attached to at least one surface thereof. Also disclosed herein are a fibrous veil and a method of making the nanofiber-doped fibrous veil.
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This is a division of application Ser. No. 08/253,664 filed Jun. 3, 1994 which is a Division of Ser. No. 08/101,940 filed Aug. 4, 1993 issued as U.S. Pat. No. 5,340,273; which is a Division of Ser. No. 07/803,007 filed Dec. 4, 1991 issued as U.S. Pat. No. 5,261,676.
FIELD OF THE INVENTION
This invention relates to new and improved pump protection systems and components thereof for isolating a pump motor and surrounding environment in which the pump is used, from a fluid pumped.
BACKGROUND OF THE INVENTION
Pumps are often used in conjunction with gases or liquids such as acids, oils, and toxins which can cause serious harm to the environment if they escape. Thus, when pumping a dangerous liquid from one location to another, it is important that neither the liquid nor gas which is often released by the liquid, escape to the atmosphere or pump areas outside the desired fluid pumping path.
In the 1930's mechanical seals were developed to overcome prior pump shaft sealing problems. This permitted a more secure seal against liquids from escaping along the shaft of the pump. However, in some cases liquid escaped when the pressure within the pump became too high for the seal to handle. The competing interests of maintaining an efficient pump and a safe pump required appropriately balancing the two requirements. Predicting the amount of safety required could only be broadly approximated based on the type of liquid to be pumped. The more hazardous the liquid, the more secure the seals.
The other problem with the mechanical seals of the 1930's was that the gases which were produced by the liquids were not always stopped. The seals were often easily permeated by the vapor. One solution to this problem was the creation of an arrangement known as a double seal with a barrier fluid protection. In this arrangement, the two seals form a cavity which is then filled with a clean fluid. The seal facing the excess liquid, that which does not exit the pump where desired, inhibits the movement of the liquid sufficiently to prevent passing of the liquid. The vapor which can permeate the seal is stopped by the clean fluid in the cavity.
One of the problems with this double seal system was that any failure by the first seal could defeat the protection system. Either gases from the liquid could then escape through the barrier to the environment or the liquid could break through the second seal. This would sometimes ruin the motor and the therefore the pump. A failure of the second seal prior to failure of the first seal would result in the same problems. By allowing the clean fluid to escape from the cavity, the atmosphere would effectively be on The other side of the first seal, the only remaining working seal. The breaking of seals was a problem since the fluid within had to be maintained at a high pressure to be effective, or at least a pressure higher than the pressure of the liquid being pumped.
Some development in the field created pumps in which the motor was entirely within the pump housing. One type is known as the canned motor pump. Here, the motor could fail for many reasons. Sometimes corrosive liquids would affect the motor. Also, the bearings of the motor as well as other motor parts could clog which increased downtime of the system. This type of pump further was not desirable for use with very hot or dirty liquids. Finally, the efficiency of the system could be lower because the rotating parts of the motor would have to turn within a liquid which caused additional friction during operation. Even higher friction forces occurred because sleeve bearings had to be used instead of ball bearings, since the liquid pumped filled the bearing area.
The use of magnetic pumps was an attempt to solve many of the problems by having the pump housed entirely within a single body and driven by a motor surrounding the body. The motor and pump are magnetically coupled, one magnet is attached to the motor and a magnet of opposite polarity is attached to the pump within the body. However, the magnet pump has the same problem as the canned motor pump with respect to the bearings also exposed to the liquid which is being pumped by the machine. Furthermore, the magnetic pump often generates a lot of heat which is difficult to cool sufficiently to prevent meltdown of the pump. The efficiency in operating a magnetic pump can be quite low because of the loss of energy in transferring the motor movement magnetically through the body to the pump shaft.
SUMMARY OF THE INVENTION
The principle object of the present invention is to provide a pump which enables the user to efficiently and safely pump hazardous and other fluids.
Another object of the present inventions is to provide a pump whereby the motor is protected from any fluid that might attempt to enter through the pump system.
It is still a further object of the present invention to provide a pump that has plural seals, preventing the escape along a shaft axis of liquid or gas, which seals may be adjusted during use.
It is still a further object of the present invention to provide a repeller assembly useful in a pump, wherein the repeller has a double disk and vane arrangement which reverses the direction of escaped liquid.
It is still a further object of the present invention to provide a triplex seal arrangement and components thereof, wherein the triplex seal is adjustable to act as a barrier and prevent escape of various fluids under a wide range of pressures.
It is still a further object of the present invention to provide a piston seal arrangement barrier enabling the user to manually or automatically adjust the pressure on the seal within a pump or other mechanism having a rotating shaft to be sealed.
It is further object of the present invention to provide a lubricating assembly to properly lubricate a bearing system in a mechanical arrangement having bearings surrounding a rotating shaft.
It is further object of the present invention to provide a pump having a fan assembly mounted on a housing while magnetically coupled to an environmentally sealed motor within the housing for cooling the motor during operation of the pump.
It is a further object of this invention to provide safe and efficient rotary shaft sealing methods as pumping methods.
The pump construction of the present invention comprises a pump body or casing housing a motor and a rotatable drive shaft connected thereto, with an impeller for pumping and expelling pump liquid or gas being pumped. A repeller and a triplex seal act as axial flow preventing barriers. Preferably, the pump has, in addition, a piston seal in series with the triplex seal along the drive shaft, with both seals acting as barriers to fluid passing by the impeller. The pump is, preferably, constantly and automatically lubricated by an oil mister. Finally, the motor is, preferably, magnetically coupled to a fan assembly for cooling the motor.
According to the invention, the pump arrangement or construction, preferably, has a an impeller for impelling of fluid through the pump and the impeller is mounted on an axially extending drive shaft. A repeller, comprising a circular flange, is fixed in position on the shaft to seal the shaft against fluid flow from the impeller. The repeller acts as a barrier, although not forming a full seal. The repeller, preferably, has a plurality of radially extending vanes defining a plurality of substantially enclosed channels, each defining a radially extending opening on a surface thereof. The channels are sized and shaped to provide a volute channel for attenuating swirling fluids passing from the impeller to the repeller and to reverse directions of at least some of the fluids.
A preferred seal construction for sealing the rotating shaft of the pump along a central axis of the shaft has a sealing flange or disc fixed to the shaft for rotation therewith. The flange carries a circular sealing surface on a first side. The sealing surface is in sliding contact at a first mating surface, with a second mating sealing surface formed by a sealing tube, so that a sliding fluid seal is formed at the mating surfaces of the sealing surface and sealing tube. The seal acts as a barrier to fluid contained in the pump and prevents flow along the shaft. The tube is operatively associated with a pressure applying surface which determines closing force of the seal, with that surface being positioned opposed to the second sealing surface. A flexible diaphragm, having at least two positions for respectively enlarging or decreasing the surface area of the pressure applying surface is provided, with the sealing tube attached thereto and being fixed against rotation about the axis of the seal and movable along the axis, to provide for sealing pressure at the mating sealing surfaces. The diaphragm defines, in part, a backup chamber for the sliding rotary seal.
In a preferred embodiment, the rotary seal includes monitoring means in a backup chamber, for allowing liquid or gas access and egress from the chamber, and for measuring pressure within the backup chamber. Preferably, a plurality of fixed stops limit the two positions of the flexible diaphragm.
In the most preferred embodiment, the seal is a triplex seal and comprises a plurality of three coaxial tubes having three sliding surfaces defining two backup chambers. At least one flexible diaphragm arrangement is provided for giving the flexibility of predetermining the seal closing pressure by determining predetermined fixed positions of the diaphragm to vary the backup pressure surface and, therefore, effect sealing pressure. In this manner, sealing pressure can be minimized while providing for desired sealing with minimized frictional contact.
A method of sealing a rotating shaft against axial flow of liquids there along, comprises providing a circular flange fixed on a drive shaft, with a first sliding, enclosing sealing surface on the flange, and tube means having a mating surface for contact with the sliding surface. The tube means is provided with a pressure applying surface and diaphragm means for varying pressure on the pressure applying surface. Fluid on one side of the flange applies a sealing pressure and the sealing pressure is modified to actually compress the tube against the flange to form a sliding seal, which modification is carried out by proper selection of diaphragm position to vary a pressure applying surface.
According to the invention, a pump comprises a pump shaft having a central axis and flange fixed to the shaft carrying a circular sealing surface thereon forming a mating seal surface. A spring loading sealing tube is resiliently urged toward the first mating seal surface and the tube defines a rear surface for defining a sealing pressure on the seal surface. The tube is stationary with respect to axial rotation about the axis, but is resiliently fixed for movement along said axis caused by pressure on the pressure applying surface. A fluid reservoir has a defined volume and means for varying the volume or pressure of fluid to vary hydraulic pressure in the fluid reservoir and, therefore, vary the sealing pressure.
A mechanism is provided for simultaneously providing lubrication to two coaxially located, spaced apart, substantially coaxial rotary bearings mounting a shaft such as a pump shaft. A dispenser is mounted coaxially with the coaxially aligned rotating bearings. The dispenser rotates in a liquid reservoir and has means for entraining a liquid from the reservoir and bringing liquid to nozzles provided on the dispenser, to dispense the liquid from the nozzles directly to each of the rotary bearings. Plural nozzle means direct the fluid in the direction desired and preferably act as misters to mist the lubricating fluid. The dispenser can use a plurality of bristles as nozzles, or can have oppositely directed nozzles to preferably provide just the lubrication necessary and no over supply of liquid which might tend to obstruct the bearings. The bearings can be sealed so that no outside contaminants are exposed to the bearings.
An enclosed pump motor construction has a magnetic means mounted on a motor shaft for rotation thereabouts. An environmentally leak-proof, non-magnetic casing encloses the motor and motor shaft with a cooling fan being independently mounted for free rotation on an axis coaxial with the axis of the motor workshaft and is located outside of the casing. The cooling fan means carries a second magnetic means for coupling with the first magnetic means to turn therewith when the motor shaft is rotated, whereby the pump motor is cooled by direct flow from the cooling fan.
In still another rotary seal for rotating shafts, a disc is fixed to the shaft for rotation therealong. The disc defines a first sealing surface encircling the shaft. A tubular member is coaxially located with respect to the shaft and stationary about the axis of rotation of the shaft, but mounted for movement along the shaft by resilient means to engage the first sealing surface at a second sealing surface of the tube. The tube has a rear pressure applying surface opposed to the seal surface and a fluid chamber contacts the pressure applying surface. Means are provided for varying pressure in the chamber to vary the sealing pressure at the sealing surface of the disc and tube. Preferably, the chamber is filled with a fluid and the fluid pressure is varied by the use of a reciprocal piston. The piston can be reciprocated by a screw cap, as desired, to obtain the desired sealing pressure.
Pumps in accordance with the invention use one or more of the seals of this invention. In the most preferred embodiment, a pump construction has a repeller means, triplex seal, piston seal and isolated fan means in accordance with this invention.
It is a feature of this invention that dangerous fluids can be easily pumped, utilizing one or more of the features of the present invention and, preferably, all of them in a preferred pump construction. A leak-proof pump is obtained which can meet critical emission controls set out by substantially all environmental protection and government laws. The triplex seal, in particular, acts as a positive seal against fluid pressures of from 0 p.s.i.a. to 425 p.s.i.a. along the axis of the shaft. Thus, the most difficult seal, i.e., the first fluid seal after the repeller, is of novel construction which permits good sealing, yet minimized friction by proper preselection of sealing pressure. The triplex seal can be monitored to determine pressure in a backup chamber thereof. Automatic pump shut-down can be carried out if monitoring uncovers a pressure change that indicates fluid leakage. The triplex seal and variants thereof can be used as shaft seals in a number of different end uses. The repeller used can vary greatly, although the preferred construction provides a good means for reversing a substantial amount of flow towards the impeller in the pump arrangement of the present invention.
Because the pumped liquid never enters the bearing chamber and because the rotary bearings can be lubricated by the dispenser, full ball or roller bearings can be used, rather than conventional sleeve bearings. This permits maximum thrust and radial load resistance for longer pump life and lower heat generation. Because the triplex and pump seals are barriers, pump fluids do not pass to the bearings and the pumps of this invention can pump particle carrying fluids that would otherwise contaminate the bearings.
The second seal, having a piston acting to provide sealing pressure, provides good backup protection in an environmental pump, as does the seal obtained by encasing the motor and providing for cooling outside of the flow path of the pump and outside of any leakage flow path of the pump. In spite of the many seals and positive flow barriers provided by the pump of the present invention, pumps can vary in size and purpose for a wide variety of purposes, including pumping of acids, bases, gases, compression of gases and the like. Moreover, such pumps can be constructed using substantially conventional construction techniques at minimized cost and expense, with high reliability and accuracy, using conventional motors, bearings, impellers, casings and the like.
These and other objects and features of the present invention will be better understood and appreciated from the following detailed description of basic embodiments thereof, selected for the purpose of illustration and shown in the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross-sectional view of the pump;
FIG. 2 is cross-sectional view of the pump taken along line 2--2 in FIG. 1;
FIG. 3 is an enlarged fragmentary end view through line 3--3 of FIG. 1, showing an end of the repeller;
FIG. 4 is an enlarged fragmentary longitudinal cross-sectional view of the impeller portion;
FIG. 5 is an enlarged fragmentary longitudinal cross-sectional view of the triplex seal arrangement;
FIG. 6 is an enlarged fragmentary longitudinal cross-sectional view of the piston seal arrangement;
FIG. 7 is an enlarged fragmentary longitudinal cross-sectional view of the oil mister;
FIG. 8 is a cross-sectional view of the oil mister taken along 7--7 in FIG. 7;
FIG. 9 is cross-sectional view of a portion of the oil mister taken along 9--9 in FIG. 8;
FIG. 10 is an enlarged fragmentary longitudinal cross-sectional view of a second embodiment of the oil mister;
FIG. 11 is a cross-sectional view of the second embodiment of the oil mister taken along 11--11 in FIG. 10;
FIG. 12 is cross-sectional view of a portion of the second embodiment of the oil mister taken along 12--12 in FIG. 11;
FIG. 13 is an enlarged fragmentary longitudinal cross-sectional view of a third embodiment of the oil mister;
FIG. 14 is a cross-sectional view of the third embodiment of the oil mister taken along 14--14 in FIG. 13;
FIG. 15 is an enlarged fragmentary longitudinal cross-sectional view of the motor fan arrangement.
DETAILED DESCRIPTION
A preferred embodiment of a pump in accordance with the invention intended for very high speed pumping of hazardous liquids such as acids and the like, is shown at 20 in FIG. 1. The principle components of the pump 20 comprise an electric motor 21 within an overall casing 22, having a drive shaft means 23 connected at one end to the motor 21 and at the other end to an impeller assembly 25 mounted within the composite, overall, body casing 22.
Three barrier means comprising a repeller assembly 30; a triplex seal arrangement 31; and a piston seal arrangement 32. Each barrier means is coaxial with the drive shaft means or motor drive shaft 23, and is arranged in longitudinal alignment serratim between the impeller assembly 25 and the motor 21. The barrier means function to control liquid or gas from undesired contact with either the motor 21 or the environment in which the pump 20 is used. The combination of the repeller assembly 30 and the impeller assembly 25 forms the wet end of the pump 20, shown at the right hand side of FIG. 1. At the left hand side of the pump 20, as shown in FIG. 1, a fan assembly 33 is magnetically coupled to the motor drive shaft for coaxial rotation therewith.
An oil mister assembly 34 is positioned between the barrier means and the motor 21, providing lubrication to rotary bearing assemblies 35, 36 which support the shaft 23.
Turning now to a description of each section of the pump 20 starting at the wet end, the impeller assembly 25 is best illustrated in FIGS. 1-3. A volute 40 is formed by metal casing portion 41 and inwardly extending backplate 42 defining a chamber 43 having a longitudinal extending opening forming an inflow path 44 for liquid and an upwardly extending outflow path 45. As liquid flows into the volute 40 through the inflow path 44, a disc shaped impeller 46 forces a substantial portion of the liquid through the outflow path 45.
The impeller 46, as shown in FIGS. 1 and 2, is a conventional closed impeller. In such an arrangement, the circular disc or flange shaped impeller is coaxially mounted on drive shaft 23 and includes a pair of circular facing plates, coverplate 47 and rearplate 48, with a plurality of curved radiating vanes 49 interconnecting the plates 47 and 48. The vanes 49 extend in a parabolic pattern from a domed center hub or cylindrical flange 50 of the impeller plates. The domed center hub 50 helps reduce the turbulence created by the high pressure liquid as it enters the volute 40. The rear plate 48 has a part of hub 50 which is threaded to engage a threaded portion 51 of the shaft outer end 52. Thus, the impeller 46 is coaxial with and rotates at the same rate as the shaft 23 as does the repeller.
The impeller assembly casing 53 encloses the impeller and is attached to an inflow pipe 55 at bolted, circular flange 54, an outflow pipe 55A at bolted, circular flange 56 and the overall casing 22 by a bolted circular flange 58 through eight circularly arranged screw thread bolts 57.
A screw threaded drain plug 59 and associated drainage port is mounted to allow through draining of the impeller assembly throughout the pump 20 drain plugs or fluid ports 59-63 allow for complete draining, cleaning and/or filling of their associated casing sections.
In the present embodiment, the impeller assembly 25 meets the approximate performance specifications of standard pump of ANSI/ASME B73.1M-1984. The impeller assembly 25 measures 3×1.5×8 inches. Thus, the impeller diameter for this configuration is a maximum eight inches. In such an arrangement, there are usually four or five vanes 49 equidistantly spaced around the impeller, however, four vanes are shown in this embodiment. If desired, conventional back pump out vanes, such as radially extending back pump out vanes 86 (shown in dotted outline in FIG. 2), can be used. Such vanes are conventional and, as known, extend from the motor side face of rear plate 48 and tend to prevent flow toward the repeller as the impeller rotates. The pump as herein claimed, is not intended to be limited to either the ANSI standards or the API standards.
After use of the pump 20, the system can be emptied of any liquid or gas remaining within the body or casing 22. This is accomplished by opening a plurality of drainage ports or plugs 59-63 located on the bottom portion of the body 22.
While most of the liquid being pumped will exit the pump 23 through the volute outflow path 45, some of the liquid may pass behind the impeller 46 into a narrow passageway 64 shown by arrows in FIG. 4 extending from the wet end of the pump toward the fluid chamber or reservoir 87 before the triplex seal. This passageway 64 is formed by the combination of the impeller 46 and repeller assembly 30 and a plurality of inwardly extending, circular, coaxial stationary body backplates 42, 65 and 66.
After the pumped liquid enters the passageway, it travels down the first vertical portion, as seen in FIGS. 1 and 4, between the rear impeller plate and the backplate 42. The centrifugal force exerted by the rotation of impeller 46 swirls the entering liquid and expels it out and back into the volute and eventually out pipe 55A.
Under sufficient pressure, some of the liquid moves rearwardly within a first horizontal portion 65 formed by the impeller hub or collar 50 and the backplate 42. The backplate 42 also forms one of the walls of a vertical portion of the passageway 64 along with a first circular extending flange or disk 70 acting as a repeller of the repeller assembly 30. The first disk 70 is fixed to the motor shaft 23 for rotation therewith and is perpendicular to the axis of the shaft. A parallel, substantially identical second disk 71 is integral with a repeller mounting element 72 which encases a substantial portion of the impeller collar 50 and is fixed with and coaxially mounted on the shaft 23.
The mounting element 72 and the backplates 42, 65 and 66 form horizontal portions of the passageway 64 that has unwanted fluid flow from the impeller past the repeller. Horizontal fluid passageway portions are further defined by a longitudinal segment backplate 42 and disk members 70 and 71. Vertical repeller passageway portions 75 through 77 of the passageway 64 are defined by the disk members 70 and 71 and the backplates 42, 65 and 66. The labyrinth shape of the passageway 64 at the repeller section alone is a difficult obstacle for the liquid to overcome in order to reach the motor 21. The upward, downward, and horizontal passageway elongates the distance the liquid must travel through the pump to cause damage or hazard at the motor or beyond in the atmosphere. Because liquid follows the path of least resistance, it will tend to remain in the volute 40 rather than traverse the vertical portions of the impeller passageway. One structure useful to achieve this labyrinth shape and minimize leakage passage ways, is use of a solid one piece construction for the double repeller element 72 combined with a split backplate 65. This also allows ease of assembly and perfect alignment and repeller separation.
In addition to the shape of the impeller passageway, other structures prevent the liquid from reaching the motor 21. Each repeller disk member 70 and 71 has a radial extending vane arrangement 80 and 81, respectively, located on a disc or flange face or side facing away from the impeller 46. In each of the vane arrangements 80 and 81, adjacent vanes such as 82 and 83 (FIG. 3 end view) are shaped so that together they define open-ended cylindrical channels such as channel 84 with substantially enclosed circular cross-sections forming 270° arcs, each opened at a mouth 85 on an inner face of its repeller disc.
By rotating the repeller assembly 30, most of the liquid attempting to travel downward and through the narrow passageway 64 toward the motor is forced into the channels 84 which reverses the direction of the liquid back toward the impeller assembly 25. It is important that the channels 84 not be completely enclosed. The combination of the liquid being pushed by the rotating repeller assembly 30 against the backplate 42, 65 or 66 imposes on the liquid an upward spiral motion which expels the liquid back up through the channels 84. The backplates 65, 66 and 42 are stationary and become a source of friction which is necessary for the liquid to assume the spiraling motion. This vortex type energy imposed on the liquid is similar to that imposed on the liquid by the back pump out vanes 86 of the impeller 46.
In the present embodiment, the parallel disk members 50 and 51 define ten radially extending circular channels 84 in each vane arrangement 80 and 81, with each channel having a length of 7.5 inches. Each disk 70 and 71 is not limited to 7.5 inch channels, but commonly includes length such as a 7.5 inch diameter with a cross-sectional width or diameter of approximately 0.5 inches. The repeller disks commonly include lengths between six and thirteen inches. Also, as few as four to six vanes is a reasonably functional configuration. The size and number of various elements of the pump are based on the type of liquid pumped and the pressure generated.
The drainage ports and plugs 59 and 63 of the preferred embodiment permits one to empty the chambers such as repeller cavity and a cavity 87 which collects liquid or gas being pumped which traverses the passageway 64 past the impeller. The liquid which could enter cavity 87 may do so in a number of manners: the liquid may traverse the entire narrow repeller passageway without ever entering a cylindrical channel 84; there is a failure in the repeller assembly 30; or, if the pressure of the liquid entering the repeller assembly 30 is so great as to overcome the substantial vortex energy generated by the repeller assembly.
After entering the cavity 87, the barrier preventing the liquid from reaching the motor 21 is the triplex seal arrangement 31 (FIG. 5). This triplex seal 31 is made up of a circular, rotating disc or flange 90 which has a cavity 87 facing side 91 and a sealing side 68 defining a sealing surface. The flange or disc 90 is coaxial with and mounted on the shaft 23 and thus rotates at the same rate along with the impeller and repeller. The actual sealing of the triplex seal 31 is the sliding engagement of a plurality of cylindrical sealing surfaces 92, 93 and 94 on the rotating flange 90 mating and forming cylindrical mating surfaces with a plurality of cylindrical sealing surfaces facing and engaging surfaces 92, 93 and 94, and provided by cylindrical tubes 96-98, coaxially with shaft 23. The initial engagement at the mating seal surfaces of the tubes and flange 90 is created by the combination of spring elements 100, 101 and 103 and rods or anti rotation pins 104, 105 and 106, respectively. Equally spaced and coaxially arranged around the triplex seal arrangement at each tube, there are ten resilient springs in this embodiment for each of the three mating sealing surfaces. The spring pressure is light and forms only a sliding contact with substantially no sealing pressure at the sealing surfaces. The tubes move longitudinally, but are stationary against rotation.
The liquid or gas being pumped which may enter the cavity 87, travels over the right hand side of the rotating flange 90 to the outer edge of sealing surface 92 and sealing tube 96. The liquid or gas then enters neck 110 where the liquid applies inward pressure on a flexible cylindrical diaphragm 111 having a thickness ranging from 0.003 to 0.004 inches. The amount of inward movement of the flexible diaphragm is limited by a top cylindrical shelf 112 of a cylindrical receptacle 113. The outward expansion of the flexible diaphragm is limited by bottom shelf 114 of block arrangement screwed to a mounting flange 116 fixed against movement by a circular flange of a circular housing or casing portion 119. Casing portion 119 is bolted by eight circumferentially arranged bolts at each end, as shown, and associated casing flange.
During operation of the pump, the flexible diaphragm 111 has two possible positions. One position is assumed when the diaphragm 111 is pressed against the top shelf 112, and the other when the diaphragm 111 is pressed against the bottom shelf 114. While having the diaphragm assume a position between the two mentioned positions is theoretically possible, practically it does not occur in use of the pump.
The position assumed by the diaphragm 111 defines the area at a pressure applying surface 120 to which pressure is applied to the sealing tube 96. The cylindrical diaphragm 111 is mounted by a clamp provided by clamping rings or blocks 116, 116a and 116b, all sealed by resilient O-ring seals 130 on flange 119. In addition, the diaphragm 111, 171 and 170 each serve as either a primary or secondary seal, depending on temperature requirements. The sealing tube 96 and diaphragm 111 are mounted at the flange end 119 by bent over continuous, circular, metal collars or stabilizer holders 140 and 141 welded, press fitted or otherwise attached to each other as shown at FIG. 5.
The area of surface 120 comprises that portion of a circular holder 140 which is either between the cylindrical, longitudinal plane defined by the bottom shelf 114 and the flexible diaphragm 111 in a radially outward position, or between the cylindrical, longitudinal plane defined by the top shelf 112 and the diaphragm 111 in the inward position. By extending the distance between the top shelf 112 and the bottom shelf 114, one may vary the pressure applying cylindrical area of surface 120. The seal pressure applying surface 120 is made up of the entire face of the collar 140 facing the motor, but its area is varied by movement of the diaphragm as described. The diaphragm can be of rubber, plastic or any resilient material including metals.
The pressure applying area dimensions are selected based on the amount of closing force desired on the sealing surface of tube 96 against the flange or disc sealing surface 92. In the present embodiment, the area 120 is 75% of the facing mating surface of the sealing tube 96 which engages the sealing surface 92 of the rotating flange 90. With more viscous liquids, a greater percentage pressure applying surface may be necessary. By creating a system wherein the pressure applying surface is always proportional to the sealing surface, one minimizes the frictional forces while maintaining a desired fluid seal across the mating sealing surfaces of the flange 90 and tube 96. Continuous circular sealing rings 160, 161, 169 abut the tubes 96, 97, 98 respectively and are mounted on and fixed to the sealing surface of flange 90, preferably in circular grooves as shown in FIG. 5.
Chambers 162 and 163 are formed between the sealing tubes and may be filled with a gas or liquid as desired through injection ports 164 and 165 which define circular bores leading to the chambers. Often, one of the chambers 162 or 163 will be filled with a second liquid other than that being pumped. Such liquid can be used to apply pressure to the associated diaphragm to counteract or adjust the effect of fluid which may fill chamber 87 and act on sealing surface 92 and the outside of diaphragm 111 Liquid or gas in backup chamber 162 and/or chamber 163 can be used to monitor pressure in each chamber and/or detect leakage in each chamber. The injection ports 164 and 165 may also be used to monitor the amount of pressure in chambers 162 and 163 respectively, and to determine whether greater pressure is required to prevent the seals formed at sealing surfaces 92, 93 and 94 from opening.
While only the diaphragm 111 and its associated tube 96, with mating and sealing surfaces and holders as claimed, has been described. Identical parts are used and duplicated to form the triplex seal. Thus, diaphragms 170 and 171 are mounted through mounting rings or holders 172 and 173, bolts 174, holders 180, 181, 182 and 183 to form the triplex seal having dual chambers 162 and 163, with each tube having its backup diaphragm so as to provide a pressure applying surface whose area can be varied to vary the sealing pressure at the mating surfaces of each tube and each sliding contact surface with the disc 90.
The right hand side of the disc 90, as shown in FIG. 5, is first exposed to the fluid that passes the repeller, filling chamber 87 and also applies a pressure to the diaphragm and to the pressure applying surface 120. The pressure applying surface of tubes 97 and 98 are only activated by pressure within the chamber 162 and 163, and only by predetermined pressure caused by filling these chambers if desired. In the only case of other pressure being applied in chambers 162 and 163, there would be a differentiation in pressure which is predetermined in the chambers if there is leakage through the first tube 96, causing a different pressure on the rear pressure applying surface of tube 97 and, similarly, if there is leakage of fluid from chamber 162 through tube 97, there would then be a different pressure on the pressure applying surface of tube 98. In some cases, the liquid pressure in chamber 87 may be the predetermined pressure applied in chambers 162 and 163.
In some cases, a single tube 96 and diaphragm 111 can be used and the chamber 162 is the only chamber which is, in fact, a circular chamber with no tubular arrangements defined by tubes 97 and 98. Similarly, a double seal can be formed or quadruple or higher numbers of rotating sealing surfaces can be used.
The flange 90 is fixed to the pump shaft 23 and suitable resilient O-rings, gaskets or other means are used to provide conventional positive seals as at 190.
If unwanted, excess liquid pumped passes through the triplex seal, the next barrier which the liquid meets is the piston seal arrangement 32 (FIGS. 1, 6). A cylindrical piston head 188 has a cap 189 which is threadably engaged to a piston body 192 by screw threads 193 and 184. The piston body 192 has additional screw threads 185 to engage the screw threads of a cylindrical casing portion 186 of main casing 22. A piston stem 199 is fixed and attached to the piston cap 189 and extends into the piston head 188. The stem 199 is held stationary with the cap by a disc seal 205. A resilient O-ring seals a sliding reservoir disc 191. The piston body opening 194 coincides with a channel bore 195. The channel 195 extends into a circular reservoir or pressure applying chamber 196 which forms a ring coaxial with the shaft 23 and is bounded on one side by an axially slidable circular ring holder 197 which secures an axially sliding sealing tube 198 in position.
The cylindrical tube 198 is identical to tubes 96, 97 and 98 and has the same sealing function at a circular sealing surface of a rotating cylindrical sealing surface 210 of a flange or disc 201 which is fixed to shaft 23 by threaded pin 202 and O ring seal 203. The reservoir or chamber 196 is concentric with the shaft 23 tube and pressure of hydraulic liquid therein applies pressure to sealing surface 200. The stationary sealing surface or face 210 of the tube mates with a cylindrical sealing and mating surface 200 forming a seal therebetween. To prevent the rotation of the longitudinally slidable tube, a group of anti-rotational pins 211 having circular or non-circular cross-sections extend through the reservoir 196 and into the stationary holder 197. The pins 211 are four in number arranged in a circle coaxial with both the shaft 23 and tube 198 and spaced equidistantly around the piston seal arrangement. The number of pins 211 can vary with two or more such pins normally used. The tube 198 is secured to holder 197 which is attached to a circular flange portion pump casing 186, against rotational movement. The tube 198 and holder 197 slide on pins 211 when pressure is increased or decreased in circular reservoir 196.
The rotary sliding surface 200 rotates at the same speed as the shaft 23. The strength of the seal created by the face 200 and the relatively rotary face of the tube is increased by screwing down the piston cap 181 to create more pressure in the reservoir through the piston 180. This increase in pressure translates to more pressure on the rear pressure applying face of holder 197, which increases the pressure on the mating surfaces of the tube 198, a mating circular disc 201, as the disc rotates, as well as when it is stationary. The disc 201 provides the mating sealing surface 200.
The piston seal may only be useful if the pumped liquid or gas has passed through the triplex seal arrangement and repeller into chamber 204. The friction that is created by sealing the rotary face of disc 201 against the stationary face of the tube 198 can decrease the efficiency of the pump and thus the piston seal may be deactuated or adjusted as desired by means of the piston pressure in particular situations. By attaching a pressure gauge to one of the injection ports 164 or 165, one may automatically activate the piston seal if escape of the liquid beyond the triplex seal arrangement is detected to be imminent. Thus, the user need only allow the piston seal to actuate when necessary, if this is desired.
Alternately, the piston seal can be maintained at a relatively low seal closing pressure at all times to maintain the oil within the bearings from leaking out to chamber 204.
Turning now to the oil mister assembly 34, as best shown in FIGS. 7-9, a casing 186 defines a chamber 250 surrounding the shaft 23 and having a lower well 187 which can be filled with a lubricating oil or other liquid. Conventional rotating bearings such as ball bearings are shown at 251 and 252, coaxial with and mounting the motor shaft 23 for rotation. The bearings each are of conventional ring design with a plurality of sliding balls such as 252, 253, and 254 coaxially arranged about the shaft 23, as known in the art. The ball bearings allow free rotation of the shaft.
A dispenser 260 is fixed to the shaft for rotation therewith on a sleeve 261. The dispenser 260 has nozzles formed by bores 262 and 263 on opposed sides of the dispenser body. The bores 262 and 263 are each associated with a tubular passageway 264 having scoops in the form of hood 265 and 266 which are mounted on a disc of sleeve 261 keyed to the shaft 23. The disc defines the scoops as entraining means for directing lubricating liquids to their respective nozzles. The nozzles are directed outwardly and forms means which are mounted in a pathway defined by the dispenser disc. Since the nozzles are directed towards each rotary seal, on opposed sides of the disc or dispenser, as the shaft rotates by rotating the scoops of the disc, a controlled flow of liquid or mist is automatically passed to the bearings. By suitable selection of the scoop and nozzle arrangement, one can direct the fluid exactly where one wants to direct the fluid, that is, toward the ball bearings, without immersing the bearings in fluid, yet allowing a sufficient amount for lubrication.
Proper selection of the scoop's rotation and nozzle means also allows a misting action to mist the lubricating fluid such as oil. Thus, a spray can be directed at the ball bearings directly where needed from opposing faces of the dispenser in a rotary motion, thereby misting the ball bearings without causing liquid filling which might hamper the rotary bearing action.
FIG. 9 illustrates the action of the scoop in a cross-section as the dispenser rotates. Direct lubrication of the bearing could flood the bearing assembly and increase friction, Preferably, misting action is desired and proper placement of the dispensed fluid or liquid as the shaft rotates is preferred. In an alternate embodiment of the mist arrangement shown in FIG. 10-12, the dispenser 270 is in the form of a disc which has an encircling groove perpendicular to the axis of the shaft. The groove is provided with nozzle means 271 and 272 and a scoop action provided by channels 273 and 274 which rotate in the fluid chamber as shown. Thus, the nozzle means provide for flow of oil, preferably in misted form, towards the bearings on opposed sides of the dispenser 270.
In still another arrangement for providing oil to the opposed rotary bearings, a coaxially arranged dispenser 280 carries a plurality of bristles 281 which are mounted on the shaft 23 for rotation therewith. As the bristles, which can be wire bristles, are rotated through the trough carrying the oil, the oil is picked up, misted and directed toward the opposed rotary bearings. The bristles can be mounted on a suitable disc sleeve 290 in any conventional manner known in the art. In the present case, they are adhesively adhered through adhesive means not shown. Welding, soldering and the like can be used. The wire bristle dispenser of FIGS. 13 and 14 provides for a fine mist which is particularly preferred.
Turning now to the next section of the pump of this invention, the pump motor 21 has a casing portion of housing 22 of any conventional design and has its shaft, indicated at 23, passing through the motor. Conventional bearings 324 are provided as known in the art, as is a rotary end seal coaxial ring 326. The motor drive shaft 23 has a reduced diameter end 327 mounting a doughnut-shaped magnet 328. The magnet and shaft are enclosed in an end cap 329 bolted to and sealed to the motor end by 8 circularly, evenly spaced, arranged screw threaded bolts 330, with sealing O-ring resilient gasket 331 of a suitable neoprene or other rubber, as can be used for any of the seals of this invention. O-ring seals can also be of metal as known in the art.
Because the end cap 329 is used, the motor is totally sealed. The cap is of a non-magnetic material such as plastic as known in the art. Non magnetic metals can also be used for the cap. Thus, the sealed motor provides a further barrier. Should any hazardous liquid or gas escape along the shaft to the motor, it will be stopped by the cap.
The doughnut 328 provides for actuating through the drive shaft 23, a cooling fan shown at 400. The fan 400 is mounted by bolt 701 on a rotary bearing 401 which is fixed by a shaft 402 to an outer flow directing casing 403, 8 bolts 404 and washer standoffs fix the casing or cap 403 to the motor casing. Air passageways are provided as shown by arrows 410 to allow cooling environmental air and other fluid from the fan 400 to be directed from the environment through holes 700 along the motor casing, as shown by the arrows 410. The fan 400 can be any standard fan blade. A magnetic mass, as of iron where a magnet is used for the doughnut 328, is provided in the form of an inset encircling ring 420. Thus, the magnetic mass 420 is actuated by rotation of the motor shaft 23 through the doughtnut 328 of magnetic means as known in the art, to provide a cooling action to the motor, yet have the cooling fan sealed and environmentally protected from possible escape of fluids through the pump.
As known in the art, the magnet and iron or magnetic mass can be switched with either mounted on the shaft or the fan blade. Opposed pole drive magnets can be used as known in the art.
Mounting support brackets 800, 803 can be used along with adjusting bolts and mounting bolts 802. Conventional stands or holders of known types can be used.
While specific embodiments of this invention have been shown and described, many variations are possible. In all cases, it is desired to prevent fluid or gas escape along a drive shaft when a pump is operated by a drive motor. This is particularly important when pumping hazardous fluids. In some cases, individual components of this invention can be used in other rotary sealing or fluid impeding devices, as for example, sealing rotary shafts of compressors which are considered pumps, or other rotating devices.
While specifics have been described, various sizes, dimensions, pumping values and the like can be used, as will be obvious to one skilled in the art. Generally, pumps are used for pumping hazardous fluids under ratings of various EPA and OSHA regulations described in public law 101-DTD November 1990. This is exemplery but not inclusive jof all dangerous, toxic, carcinogenic, and volatile compounds. While all components of the pump are preferably metal, except as specifically described, many materials can be used as known in the art. The tubes which form the sealing surfaces can, for example, be formed of tungsten carbide, carbon, silicone carbide or other materials. Similarly, the blocks or rings which form the mating sliding seal surfaces can be formed of the same materials or different materials, including carbon, tungsten carbide, silicone carbide and metals. In some cases, sliding seals can be formed between polytetrofluoroethylene, Kel F (a trademarked product of DuPont, Wilmington, Del.) or other low friction materials.
Particularly with regard to the triplex seal, a single sealing surface of an enclosing circular seal can be formed by a single tube and diaphragm arrangement with limiting stops on either side of the diaphragm. The particular seals of this invention can be used alone, in combination, or in any combination of parts enclosed herewith. Obviously, if a single seal or more than one barrier means is eliminated from the pump, its sealing function will be lost but other seals remain as described.
The fact that the pump can use ball bearings for the opposed bearings of the drive shaft, thus avoiding sleeve bearings, and the fact that a series of drain plug can be used to provide simple and complete drainage of fluid in the pump safely, prior to tear down of the pump for cleaning and repairs, is particularly useful when pumping fluids which may have particles which would otherwise perhaps obstruct sleeve bearings or cause problems in pumps of this nature.
While circular sealing surfaces have been described, disc and circular flanges all mounted coaxially with the shaft, or other configurations can be provided as known in the art. Thus, the shaft and casing need not be of circular cross-section, but can be of square or irregular cross-sections if desired. In all cases, the sealing surfaces are encircling about the shaft to fully seal the shaft against fluid flow from the right hand end to the left hand end of the pump as shown in FIG. 1. Although the casing is a multipart casing bolted together using suitable seals as known in the art, casing design can vary greatly. In some cases, repellers can be eliminated and seals alone or a single seal used to prevent damage to the fan motor and environment by fluids pumped by the pump of this invention.
It is not intended that the scope of this invention be limited to any single embodiment illustrated and described. Rather, it is intended that the scope of the invention be determined by the appended claims and their equivalents.
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A motor driven environmentally safe pump includes a sealed motor housing (22) sealingly affixed to a sealed pump housing. The pump housing defines a fluid pumping chamber (43) in which is a fluid pumping impeller (46). A triplex rotating seal (31) is disposed rearward of impeller (46) within an annular fluid chamber (87) so as to prevent the fluid being pumped via the impeller (46) from leaking along the shaft (23) toward the motor (21). A piston seal (32) is provided adjacent a second fluid chamber (204), the piston seal also for preventing fluid from leaking into the motor housing and damaging the motor.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to high speed printing machines and more particularly to in-line printing apparatus for containers such as bottles or the like that are being successively moved along a predetermined path between a container production line and a container filling line.
2. Description of the Prior Art
The prior art printing apparatus generally employs intermittent motion in which the containers are first loaded, then moved step-wise, then stopped for the printing step and then linearly indexed away from the printing station. Prior art devices presently available are limited to a completion rate of about 60 to 80 containers a minute. Higher speeds have been claimed but have not been attained in practice. It will be readily apparent that the prior art mode of operation is excessively time consuming and therefore relatively costly. It will be equally apparent that an automated printing process that is integrated with both the container fabricating and the container filling production lines would be much more advantageous. The prior art devices, because of their "start-stop" mode of operation, interfere with the continuous running of the production line. More important, the limited speed of prior art printers prohibit an in-plant, in-line installation because most lines, especially for smaller size containers, fill at a rate of between 100 to 600 containers per minute.
As is well known in the industry, preprinted containers require average procurement lead time of from 6 to 8 weeks. Preprinted containers, of the type referred to, include plastic or glass bottles such as used by manufacturers of cosmetics, household items or foods or the like. Because of the wide variety of products that any particular manufacturer may be producing, it is necessary to have a large supply of containers of each size on hand at all times. For example, a manufacturer of cosmetics or household items may package from 10 to 15 items in identical containers in the usual sizes of 1/2 pint, 1 pint, 1 quart, etc. A full supply of each size container must be on hand covering at least the procurement lead time.
It will be appreciated that because of the wide variety of products that any one particular manufacturer may produce, it is necessary to have a large supply of containers of each size on hand at all times. For example, each item and each size container may be packaged under as many as 40 different distributor and private labels. The need for large inventories will become more apparent when it is realized that the quantities are based on projected sales schedules and that the actual sales may vary from these estimates. Further, when a specific item is ordered on a rush basis, it has, in the past, been necessary to wait until the containers were preprinted and, as mentioned above, this frequently takes 6 to 8 weeks.
SUMMARY OF THE INVENTION
The present invention provides an in-plant, in-line automatic and continuous container printer the advantage of which will be recognized when it is considered that many super markets sell a large percentage of merchandise under their own brand name and without preprinting of the containers. It is virtually impossible for any supplier to have a sufficiently large inventory of each brand name, in order to accommodate the sales requirements for each supermarket chain. The economics possible with an in-plant, in-line printer may be up to 75 percent of present costs for those products normally found in a supermarket, for example. This results in a substantial benefit to both the consumer and the manufacturer. By the use of an in-line printing station having a readily removable and changeable printing screen, preprinted containers are not necessary.
The fully automated operation of the present invention does not require a full time printer in attendance. Simplicity of operation of this invention permits regular line operators, whose main function is to lend a hand when automation misses occasionally and to make periodic adjustments, to also attend the improved bottle printer comprising this invention.
In its broadest aspect, the present invention provides a loading section for receiving successive individual containers, such as plastic or glass bottles or the like, and for moving them in a timed relationship through a flame-treating station, where necessary, and then towards and past a semicircular printing station having a plurality of squeegees that imprint the containers as they pass a stationary screen. Should a container be absent from the container transport mechanism, sensing means will detect the absence and prevent the squeegee from contacting the screen so that ink cannot be applied to the printing screen. The importance of the no container/no print feature of the present invention will become evident when it is realized that an empty station could cause excess ink supply through the screen thus causing smearing of the next 15 to 20 bottles until the excess ink has been used up. In a production line that runs for example, at the rate of 220 containers a minute, as many as 20 containers could have unsatisfactory printing without the no container/no print feature of the present invention.
The present invention provides container printing apparatus that is particularly useful in the economical printing of no deposit-no return round containers regardless of the size, or material of the container. The present invention provides production economies in that it is suitable for in plant-in production line installation and meets the production speed of the container filling lines that are presently in existence.
Container manufacturing equipment such as blowmolders are, by nature of their operation, slower than their associated filling line. However, it is practical to install several container molders whose combined capacity meets the filling line speed. In a container manufacturing plant, such as incorporated in a typical dairy filling line may utilize the improved printer of this invention to service as many as five blow molders, thus greatly reducing capital investment, space requirements and labor cost. Presently available prior art devices may require a printer for each molder. Moreover, in-plant molding requires in-plant printing.
Accordingly it is an object-of the present invention to provide improved apparatus for automatically and continously printing the outer surface of a no deposit/no return container such as a plastic or a glass bottle.
It is another object of the present invention to provide apparatus, as described above, that may be used inline with existing container fabricating and filling installations.
A further object of the present invention is to provide printing apparatus, as described above, having synchronized means for transporting the containers therethrough.
Still another object of the present invention is to provide printing apparatus, as described above, including means for preventing the application of printing ink onto a screen when no container is present.
These and other objects, features and advantages of the invention will, in part, be pointed out with particularity, and will, in part, become obvious from the following more detailed description of the invention, taken in conjunction with the accompanying drawing, which forms an integral part thereof.
BRIEF DESCRIPTION OF THE DRAWING
In the various figures of the drawing, like reference characters designate like parts. In the drawing:
FIG. 1 is a schematic, fragmentary side elevational view illustrating one embodiment of the present invention;
FIG. 2 is an end elevational view, taken along line 2--2 of FIG. 1 illustrating two side-by-side printing machines comprising the present invention;
FIG. 2A is a fragmentary elevational view, on an enlarged scale illustrating a component shown in FIG. 2;
FIG. 2B is a fragmentary elevational view illustrating an alternative construction for the component shown in FIG. 2A with certain components omitted for clarity.
FIG. 3 is an enlarged, fragmentary elevational view illustrating the loading section comprising the present invention;
FIG. 4 is a transverse sectional view of the loading section taken along line 4--4 of FIG. 3;
FIG. 5 is an enlarged side elevational view of the combined flame treating and printing sections comprising the present invention;
FIG. 5A is a perspective view of an oblong rack used in the printing sections shown in FIG. 3 and FIG. 5;
FIG. 5B fragmentarily and schematically illustrates an alternative oblong rack assembly together with the cam rail and idler gears associated therewith;
FIG. 6 is a fragmentary side elevational view illustrating a first drying section of the present invention;
FIG. 7 is a fragmentary plan view taken along line 7--7 of FIG. 6;
FIG. 8 is an end elevational view of the structure shown in FIG. 6;
FIG. 9 is an enlarged fragmentary elevational view, partially in section, illustrating the printing section of the present invention;
FIG. 9A is a schematic end elevational view illustrating alternative sensor means;
FIG. 10 is a side elevational view of the structure shown in FIG. 9; and
FIG. 11 is a fragmentary elevational view of the unloading section of the present invention that may be positioned between the first and second drying sections.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, and in particular to FIG. 1, there is shown the improved container decorating machine 20 comprising the present invention. The container decorating machine 20 is adapted to be placed immediately downstream of the container fabricating apparatus which is conventional and which is not shown. Similarly, the container decorating machine 20 is adapted to be placed immediately upstream of the container filling machine which is also conventional and which is not shown.
Basically, the container decorating machine 20 of this invention comprises four sections. The first section is a loading station 22. The second section is a printing station 24 which includes a flame treating station 25 having a safety valve, thermocouple and pilot light at the input end thereof. The flame treating station is particularly advantageous for the plastic containers to ensure that the subsequently applied ink will hold. The third section is the relatively short, first drying station 26 which is located immediately downstream of the printing station 24, and to the right thereof as shown in FIG. 1 for eliminating most of the volatile fumes which are exhausted outwardly by any suitable means. Finally, the fourth section is an unloading station 28 which is downstream of and to the right of the drying station 26, as shown in FIG. 1.
Where plastic containers are to be decorated, only a single drying station 26 is needed. Where glass bottles are to be decorated, a relatively longer, second drying station in the form of a heated tunnel 29 is required and is positioned immediately downstream of the unloading station 28 (FIG. 1). The second drying tunnel 29 may have to be longer and wider, for example 8 feet wide by 30 feet long, so as to contain as many as 2,000 bottles at the rate of 250 bottles per minute for eight minutes of drying and cooling. An elongated, serpentine path may be provided for the bottles in the second tunnel 29. This is necessary when the bottles are washed after printing and before filling. A special ink must be used for a caustic bath of 6 percent solution at 140° for 6 minutes. The ink must be cured sufficiently to withstand the washing without damaging the printing. By way of comparison, the first drying station 26 shown in FIG. 1 may be 5 feet long whereas the second drying tunnel 29 may be 30 feet long.
Turning now to the loading station 22, reference may be had to FIGS. 3 and 4 in particular. There is provided a chute 30 for delivering a stream of round bottles B to a conveyor that is generally designated by the reference character 32. The bottles B are individually fed to a plurality of pairs of laterally spaced apart U-shaped brackets 34 that are spacedly carried along on first endless belt means in the form of a pair of laterally spaced apart hollow pin chains 36 which will be described more fully hereafter. The brackets 34 are closely spaced so that a container cannot fall therebetween. A first plurality of roller means in the form of sprockets 38, 40 and 42 define a generally triangular and generally counterclockwise path for the chains 36. Drive means for the sprockets 38, 40 and 42 may be had by right angle bevel gear means 43 which are coupled to a drive motor (not shown). Immediately to the left of and below the chute 30 and in the direction of the counterclockwise travel of the chains 36, a housing 44, preferably with plastic guide rails to avoid scoring glass containers, is provided in order to retain the bottles B during their travel.
After being carried by the brackets 34 and the hollow pin chains 36, the bottles B travel into the printing station 24 (FIGS. 2 and 5) which is supported by track means 45 and roller means 45a so that the the entire section may be moved when different size containers are to be printed. Each side of FIG. 2 is set up for a particular size bottle. FIG. 2 is particularly suitable for a filling plant handling two sizes on a single common line. All line equipment is changed over to accommodate a specific size. The change over of the printer neccessitates loosening only four bolts, connecting the 90° turn shown in FIG. 1 to the main drying tunnel or regular conveyer line, moving the required size side in line with the main line and refastening the bolts. A clutch engages the side needed. The unit just described will have two loading stations 22 (FIG. 3), two first drying stations (FIG. 1) and two 90° turn stations 28 (FIG. 1). Bottle manufacturers often have small runs of many different sizes that require a single row model and a set of bottom ware holders for each size bottle. Limitation of size variation of the bottles is 2 inches in length and 1 inch in diameter. To accommodate different size bottles adjustments are made by a cam rail and adjusting blocks for correct screen contact adjustment. Where only one size is run, the adjusting blocks are still necessary to insure hair line contact with the printing screen.
Second endless belt means in the form of a pair of laterally spaced apart, endless hollow pin chains 46 are trained about second roller means which are in the form of a plurality of sprockets 48 that travel along a generally rectangular and generally clockwise path as shown in FIGS. 1 and 5. Sprocket 48b is a driving member that tends to pull, not push, the chain 46. The sprocket 48b is driven by a belt and pulley system 49 and a motor (not shown). Referring now to FIG. 2 and to FIG. 2A, it will be seen that the two hollow pin chains 46 are connected to each other by means of pins 49a that are coupled to a plurality of transverse connecting tie bars 50 and flight brackets 51 on each of which is mounted a rotatable nose cone 52 and a spaced apart bottom ware holder in the form of a cup-shaped base member 54. The nose cone 52 and the base member 54 are arranged to releasibly engage the mouth and the base, respectively, of the bottles B. As the bottles B approach the sprocket 40 in the loading station 22, for example adjacent the sprocket designated 48a in FIGS. 1 and 5, they pass between one nose cone 52, for example made of Teflon or stainless steel, and its associated cup-shaped base member 54, at which time the nose cone 52 is biased to the left as shown in FIG. 2. A non-rotatable, linear bushing supported, spring biased shaft 55 on which the nose cone 52 is mounted assures smooth operation even for glass bottles whose height dimension may vary as much as ±1/8 inch. At its opposite end, the shaft 55 is provided with a first cam follower 56 that is arranged to engage a fixed but adjustably positionable cam rail 58 so that the nose cone 52 will be urged to the left as shown in FIG. 2A. In this manner the tapered nose cone 52 enters the open end of the bottle B and thereby seats the bottles B in the cup 54. A variation of the standard nose cone 52 will be discussed later.
An enlarged detail of the standard bottle holder nose cone 52 and cup-shaped base member 54 is shown in FIG. 2A. The nose cone 52, which is made of Teflon, glass, stainless steel or plastic, is rotatably journalled by ball bearings 53 and is biased (FIG. 2A) by a compression spring 57. It will also be seen that integral with each cup-shaped base member 54, there is provided a spur gear 60 and a mating pinion 61 whose function will be described more fully hereinafter. In addition, there is also provided a second pair of second cam followers 63 that are supported on an arm 64 and which cooperate with first and second rigid bars 65a and 65b in the printing station 24 so as to provide a steadying effect on the bottle B as it passes through the printing station. The bars 65a follow a semicircular path around the printing screen which will be described subsequently and the cam followers 63 are secured in a groove so as to provide the steadying effect. The bars 65b, on the return path, serve to prevent chain whip under high speed and will prevent vibration from being set up. A resilient pressure pad 66 is formed in the cup-shaped base member 54 as is an ejector pin 68 that is axially biased by a spring 69 as shown in FIG. 2A. The bottle B is thus transported to the flame treating station 25 by the nose cone 52 and the cup-shaped base member 54 and then through the printing station 24 shown in FIG. 5 and in greater detail in FIGS. 9 and 10.
The standard nose cone assembly 52 may be varied by replacing the ball bearing 53 with a needle bearing and by placing the compression spring 57 intermediate the transverse base wall of the nose cone 51 and a shoulder formed on the shaft 55.
The printing station 24 is comprised of a fixed, arcuate screen means 70 that has the desired design formed thereon in a conventional manner. The bottles B pass the screen means 70 in tangential contact therewith. A rotating squeegee assembly, generally designated by the reference character 72 is mounted on a transverse shaft 74 to which is secured additional roller means in the form of an idler sprocket 75 (FIGS. 2 and 5) and includes a plurality of axially displaceable radially extending arms 76 each of which includes a squeegee 78 at the radially outer end thereof. Lock nuts 77 hold the arms in place but when the lock nuts 77 are loosened the arms can be moved radially for adjustment purposes. The ink is forced through the screen means 70 onto the surface of the bottles B by means of the rotating squeegees 78 which may be made of a plastic material or a 40 durometer butyl rubber. Coupling means 74a (FIG. 2) join the shaft which supports the sprockets 48b of two side-by-side container printing machines 20 so that containers of different sizes may be printed simultaneously on one common production line. The bottle and lateral surface of the screen means 70 are synchronized while bottle B travels through the printing station. Any change of speed will affect each component proportionately and will maintain precision alignment at any speed.
Concurrently the pinion 61 engages a fixedly positioned rack 80 shown schematically in FIG. 5A. The teeth of rack 80 define an outline that is congruent with the path of hollow pin chains 46 so that bottles are rotated as they are advanced. In actual practice the rack 80 is in the form of a continuous path from point 202b, and clockwise to point 202a. Between points 202b and 202a spur gears 60 engage a half gear 200 to continue counter-clockwise rotation of bottle B. Points 202a and 202b overlap the half gear 200 for several of its teeth so that smooth transfer can be had.
The no container/no print feature of the present invention is shown best in FIGS. 9 and 10. When a bottle is missing for any reason, a signal from an appropriate sensor, for example a photo electric cell 82 shown schematically in FIG. 9, actuates an air cylinder 84 and thereby moves a connecting bar 86 from the position shown in solid outline to the position shown in dotted outline in FIG. 9. The photocell 82 is applicable to substantially opaque containers. Alternatively a mechanical arrangement could be used such as a pivotally mounted flat feeler 82' that is wider than the center distance between adjacent bottle holders. An empty station will cause the feeler 82' to drop and thereby actuate a switch 87 as shown in FIG. 9A. A link 88 is connected to an arcuate, flexible cam rail 90 which is moved between the solid and dotted outline shown in FIG. 9 when the air cylinder 84 is actuated. When a bottle is present, two rollers 92, one on each side, that are integral with each of the arms 76 will ride on the radially outer surface of the cam rail 90. However, when a bottle is absent, the radially inner surface of the deflected cam rail 90 will engage the rollers 92 to thereby prevent the squeegee 78 from contacting the inside surface of the screen means 70 and in this manner will prevent ink from being deposited and remaining on the screen in the absence of a bottle B. A spring 79 normally maintains the arms 76 in their radially outer positions so that the rollers 92 engage the outer surface of the cam rail 90 when a bottle is present. Spring 79 also maintains contact pressure with the screen means 70.
When traveling at the printing station 24, as shown in FIG. 5B the spur gears 60 that are integral with the cup-shaped base members 54 engage the half gear 200. In this manner positive bottle rotation is provided as the bottles B traverse the stationary screen 70. The alternative oblong rack 80 is made up of a plurality of linear sections 94 interconnected by arcuate corner segments 96 and an arcuate, central section 98. Rack 80, without the arcuate central section 98, together with half gear 200 form an endless path. Hollow pin chains 46 move in a clockwise direction while the rack 80 and the half gear 200 are stationary. Pinion 61 engages the rack 80 and the spur gear 60 engages the half gear 200 to ensure counter-clockwise rotation of the bottles B. Also, rotation of the bottles B throughout the entire forward and empty return path ensures smooth and vibration-free operation as opposed to a gear and rack engagement at the beginning of the working cycle with consequent jarring and abnormal gear wear.
Preferably there are three times the number of container holding stations (each station being defined by a nose cone 52 and a cup-shaped base member 54) as there are squeegees 78. Only three container holding stations need by synchronized with each squeegee 78. There may, for example, be eight, nine or ten squeegees 78 and the idler sprocket 75 may have a pitch diameter of 12 to 28 inches which pitch diameter is determined by a multiple of center distances between the bottles B and the number of squeegees 78. Sprocket 75 must have a number of teeth that are a multiple of the center distance of tie bars 50. That multiple determines the number of squeegees 78. This may allow more than one bottle in the print station at one time. Locating sensor 82 or 87 as shown in FIGS. 9 and 9a, respectively, insures that only empty stations will retract a squeegee 78. This is necessary in order to allow the printing speed to coincide with the speed of the filling container so that the present invention performs its function automatically when integrated with the conventional conveyor line between the container supply and filling stations. The positive and mechanical rotation of the individual bottles B prevents even the slightest slipping between the screen means 70 and the container B to thereby avoid smearing ink on a container B. This also prevents smearing of ink on the screen means 70 which, should it occur, would cause the next several bottles B to be improperly imprinted because of an excess of ink.
From the printing station 24, the bottles B enter the drying station 26 which is shown in FIGS. 6, 7, and 8. The drying station 26 is defined by a housing 100 that is open at both ends. Infra-red heating means 102 are mounted within the housing 100. Quartz heaters are preferred for plastic containers since they heat and cool almost instantaneously in contrast to metal elements which take a long time to heat up and cool off. Thus there is little chance of burning a plastic container should there be a line stoppage when there are containers in the drying station 26. If desired, the infra-red heating means 102 may be positioned both above and below the path of the bottles B as shown in FIGS. 6 and 8. Two heaters 102 are particularly advantageous when the art work covers more than 180° of the circumference of the container. There is also provided a hollow pin endless chain 104 having a plurality of pairs of generally U-shaped brackets 106 secured thereto. The bottles B are not rotated in the drying station 26. After the nose cone 52 is retracted and the ejector pin 68, which is urged by the spring 69, axially displaces a bottle B approximately at the position of the sprocket designated by the reference character 48b in FIGS. 1 and 5, the bottle B is deposited on a connecting ramp 108 and then onto a bracket 106 and is thereby carried through the drying station 26.
After leaving the drying station 26, the bottles B are received in a plurality of laterally spaced apart rods 110 having arcuate portions that gently turn the bottles B from the horizontal position in which they are mounted in the loading, printing and drying sections 22, 24 and 26, respectively, to a vertical position so that the printed bottles B may be delivered to the filling machinery that is downstream thereof. Where plastic bottles are printed, only a single drying station is required. Where glass bottles are printed, the second drying 29 station, downstream of the rods 110 receive the bottles B for further heating.
Special problems are encountered where plastic containers are to be decorated. More particularly, the surface of the container should be rigidized so that they do not buckle when the squeegees are applied thereto. The present invention provides means for at least temporarily inflating the plastic containers.
As shown best in FIGS. 2 and 2A, each nose cone support shaft 55 is hollow and is in fluid communication via passageways 149a and 149b with its respective inflation assembly each of which is comprised of a first valve 150 such as a Schrader valve (part number 7796SP5). Conduit means 152 fluidly couple the valve 150, through a passageway 153 and a common rotary swivel joint 154, that is, in turn, fluidly coupled to a remote source of pressurized air (not shown). A fixed cam 156 is arranged so as to be engaged by a contact 158 on each valve 150 that is associated with each nose cone support shaft 55. When the bottles B are in the printing station 24 adjacent the screen means 70, the bottles B will be inflated or charged with air at the time when the squeegees 78 press against the screen means 70. The air pressure admitted to bottles B in the printing station 24 is regulated and has a constant flow throughout the printing cycle. This is necessary because blow molded bottles are trimmed of flash after molding and this often causes an imperfect neck seat that causes leakage, thus nullifying the principle of one shot air held by means of a check valve.
Turning now to FIG. 2B there is shown an alternative embodiment for supporting and transporting the bottles B through the printing station 24. Each tie bar 50 is replaced by a pair of flight pins 160 which are suitably secured to the chains 46 by inserting flight pins 160 into the holes on the pitch line of the hollow pin 160 chains. A first shaft 162 is secured to each flight pin by means of brackets 164 and 166 together with flat head screws 168.
A stud 170 threaded at each end positions the brackets 164 and 166 to a desired center distance. Moreover the stud 170 holds brackets 164 and 166 rigid in a vertical position. A pair of cam rollers 63 mounted on the studs 170 engage the print guide rail 65a to rigidize the assembly so as to prevent even the slightest rocking or dipping action of the hollow pin chains 46 which would alter the necessary hairline contact of the bottle B and the screen means 70. The construction shown in FIG. 2B compensates for length variations of glass bottles which may be as much as ±1/8 inch, is less expensive than the construction shown in FIG. 2a and is used where space is not critical.
The roller 56 is secured to one end of the first shaft 162 which is comparable to the shaft 55 in the embodiment of FIG. 2B. A first compression spring 172 extends between the bracket 164 and a first stop 174. A second compression spring 176 extends between a nose cone support 178 and a second stop 180. Screw 182 secures the support 178 to the first shaft 162 such that a needle bearing 184 may be positioned therebetween. Nose cone 186 is secured to the support 178 in any suitable manner, such as by adhesives, and is provided with a conical bore 188 that is arranged to receive a relatively small bottle with a relatively small open end such as is used for hair tonic or for a closed container having no open end. The spring 176 serves the purpose of compensating for length variations (±1/8 inch) of glass bottles.
Referring now to FIG. 5B there is shown an alternative construction for the rack 80. In this embodiment the arcuate section 98 of the oblong rack 80 is replaced by a stationary half gear 200. The cam rail 58 which has not previously been shown in side elevation is the same as in the previous embodiment. Preferably, the flight pins 160 for supporting the nose cone 52 and the cup-shaped member 54 are used in this embodiment.
Normally the pinions 61 engage the straight rack sections 202 and the arcuate corner sections 204. At the end of straight rack section 202a the pinions 61 disengage and the spur gears 60 engage the half gear 200. The pinions 61 engage the end of rack section 202b when the gears 60 disengage from the half gear 200. Rotation of the bottles B will be continuously counter-clockwise. Rotation of the bottles B, even through the return path (to the left in FIG. 5B) eliminates having to start rotation of the pinions 61 at high speed at the pick up station which would cause excessive gear wear and jarring of the line that would impair printing quality.
It should be particularly noted that the rack sections 202a and 202b are synchronized with the stationary half gear 200 and overlap by two to three teeth. The half-round screen 70 and the half-gear 200 eliminate any critical geometry.
There has been disclosed heretofore the best embodiment of the invention presently contemplated. However, it is to be understood that various changes and modifications may be made thereto without departing from the spirit of the invention.
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Apparatus for printing on the exterior surface of a generally round container such as a plastic or glass bottle or the like includes several stations that perform or cooperate to print the container. The stations are in line with each other and preferably are in line with both the production fabricating and the production filling lines of the container as well. There are four basic sections, the first of which is the loading section that successively receives and transports the individual containers towards a printing station. Before reaching the printing station, the containers may be flame-treated. After being imprinted, the containers, which up until this time are in horizontal condition pass through a first drying section and then are automatically rotated 90° to a vertical position prior to entering the production filling line. When necessary, a second drying station may be provided immediately downstream of the 90° turn mechanism and just prior to entering the filling production line. While moving through the flame-treating station, the printing station and at least the first drying station, the containers are continuously rotated about their own longitudinal axis. Actuation of a squeegee device in the printing station is prevented when no container is present.
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BACKGROUND OF THE INVENTION
The present invention relates to a protection switching method and apparatus for a PON (Passive Optical Network) system in which a plurality of ONUs (Optical Network Units) are star-connected to an OLT (Optical Line Terminal) through a photocoupler.
FIG. 24 shows the basic arrangement of a PON system.
As shown in FIG. 24 , in an OLT 106 , a transmission/reception section 101 is connected to a port of a switch (SW) 104 , and the transmission/reception section 101 is connected to transmission/reception sections 103 - 1 to 103 - n of a plurality of ONUs 107 - 1 to 107 - n through a photocoupler 102 and optical fibers 112 - 1 to 112 - n . The ONUs 107 - 1 to 107 - n are star-connected to the single OLT 106 .
The transmission/reception sections 103 - 1 to 103 - n of the ONUs 107 - 1 to 107 - n are respectively connected to subscriber terminals 109 - 1 to 109 - n . When the transmission/reception section 101 of the OLT 106 is to communicate with one of the subscriber terminals 109 - 1 to 109 - n , a control section 110 of the OLT 106 controls switching operation of the switch 104 . With this operation, identical signals are distributed from the photocoupler 102 to the ONUs 107 - 1 to 107 - n through the optical fibers 112 - 1 to 112 - n , and one of the ONUs 107 - 1 to 107 - n extracts the signal upon determining that the signal is self-addressed.
Assume that the ONU 107 - 1 determines that the signal is self-addressed. In this case, when a virtual path is established between the subscriber terminal 109 - 1 and the transmission/reception section 101 of the OLT 106 , the transmission/reception section 101 of the OLT 106 can communicate with the subscriber terminal 109 - 1 . That is, the transmission/reception section 101 of the OLT 106 can communicate with the subscriber terminal 109 - 1 through the photocoupler 102 , optical fibers 112 - 1 to 112 - n , and the transmission/reception section 103 - 1 of the ONU 107 - 1 .
FIG. 25 shows a dual arrangement designed to ensure the reliability of a PON system having such an arrangement. In the dual arrangement shown in FIG. 25 , an OLT 106 has sections of two systems, i.e., a 0-system transmission/reception section 101 a and 1-system transmission/reception section 101 b . Likewise, ONUs 107 - 1 to 107 - n respectively have sections of two systems, i.e., 0-system transmission/reception sections 103 - 1 a to 103 - na and 1-system transmission/reception sections 103 - 1 b to 103 - nb . In order to implement two systems in this manner, the OLT 106 has a selector (SEL) 105 in addition to a switch 104 and control section 110 .
The SEL 105 selectively switches between the 0-system transmission/reception section 101 a and 1-system transmission/reception section 101 b to connect the 0-system transmission/reception section 101 a to the 0-system transmission/reception sections 103 - 1 a to 103 - na of the ONUs 107 - 1 to 107 - n through a photocoupler 102 a and optical fibers 112 - 1 a to 112 - na . In addition, the 1-system transmission/reception section 101 b of the OLT 106 is connected to the 1-system transmission/reception sections 103 - 1 b to 103 - nb of the ONUs 107 - 1 to 107 - n through optical fibers 112 - 1 b to 112 - nb.
The 0-system transmission/reception sections 103 - 1 a to 103 - na and 1-system transmission/reception sections 103 - 1 b to 103 - nb of the ONUs 107 - 1 to 107 - n are respectively selected by SELs 108 - 1 to 108 - n of the ONUs 107 - 1 to 107 - n in accordance with selection of 0-system or 1-system by the SEL 105 of the OLT 106 . The selected 0-system transmission/reception sections 103 - 1 a to 103 - na or 1-system transmission/reception sections 103 - 1 b to 103 - nb are respectively connected to subscriber terminals 109 - 1 to 109 - n.
Assume that the PON system is operating with the 0-system transmission/reception section 101 a and 0-system transmission/reception sections 103 - 1 a to 103 - na belonging to an active system, and the 1-system transmission/reception section 101 b and 1-system transmission/reception sections 103 - 1 b to 103 - nb belonging to a standby system.
Note that the terms “0-system” and “1-system” are added to physically identify the respective sections. However, the 0-system transmission/reception section 101 a and 0-system transmission/reception sections 103 - 1 a to 103 - na do not always belong to the active system, and the 1-system transmission/reception section 101 b and 1-system transmission/reception sections 103 - 1 b to 103 - nb do not always belong to the standby system. That is, the 0-system and 1-system are irrelevant to the active and standby systems. The active system is a currently used system, and the standby system is a system that is used upon switching from the active system.
Assume that the 0-system is an active system in the following description. Referring to FIG. 25 , the 0-system transmission/reception section 101 a of the OLT 106 is now capable of communicating with the subscriber terminals 109 - 1 to 109 - n through the photocoupler 102 a , the 0-system transmission/reception sections 103 - 1 a to 103 - na and SELs 108 - 1 to 108 - n of the ONUs 107 - 1 to 107 - n . Assume that a virtual path is established between the subscriber terminal 109 - 1 and the 0-system transmission/reception section 101 a of the OLT 106 through the photocoupler 102 a and transmission/reception section 103 - 1 a and SEL 108 - 1 of the ONU 107 - 1 , and the 0-system transmission/reception section 101 a is now communicating with the subscriber terminal 109 - 1 .
When an abnormality occurs in the virtual path between the subscriber terminal 109 - 1 and the 0-system transmission/reception section 101 a of the OLT 106 during this communication owing to some cause, no data is transmitted from the subscriber terminal 109 - 1 to the 0-system transmission/reception section 101 a of the OLT 106 . As a result, the 0-system transmission/reception section 101 a detects the occurrence of the abnormality in the virtual path, and sends a warning signal to the control section 110 .
Upon reception of the warning signal, the control section 110 outputs a switching instruction to the SEL 105 to switch from the 0-system transmission/reception section 101 a to the 1-system transmission/reception section 101 b . With this operation, all the virtual paths between the OLT 106 and subscriber terminals 109 - 1 to 109 - n are switched to the 1-system at once. That is, virtual paths are established between the 1-system transmission/reception section 101 b of the OLT 106 and the subscriber terminals 109 - 1 to 109 - n through the photocoupler 102 b , optical fibers 112 - 1 b to 112 - nb , and the 1-system transmission/reception sections 103 - 1 b to 103 - nb and SELs 108 - 1 to 108 - n of the ONUs 107 - 1 to 107 - n.
With this operation, the communication between the OLT 106 and the subscriber terminal 109 - 1 , which has been interrupted due to the occurrence of the abnormality, is resumed upon switching to the virtual path constituted by the 1-system transmission/reception section 101 b , photocoupler 102 b , optical fiber 112 - 1 b , and 1-system transmission/reception section 103 - 1 b and SEL 108 - 1 of the ONU 107 - 1 .
FIG. 26 shows another example of the dual arrangement of a conventional OPN system.
In the arrangement shown in FIG. 26 , control sections 111 - 1 to 111 - n are added to the ONUs 107 - 1 to 107 - n in FIG. 25 . These control sections 111 - 1 to 111 - n control SELs 108 - 1 to 108 - n to switch (select) between 0-system transmission/reception sections 103 - 1 a to 103 - na and 1-system transmission/reception sections 103 - 1 b to 103 - nb . Since the arrangement of the remaining portion is the same as that in FIG. 25 , the same reference numerals as in FIG. 25 denote the same parts in FIG. 26 , and a description thereof will be omitted.
Assume that as in the case shown in FIG. 25 , a fault has occurred in one of the following components of the 0-system: a transmission/reception section 101 a , photocoupler 102 a , optical fibers 112 - 1 a to 112 - na , and the transmission/reception sections 103 - 1 a to 103 - na of ONUs 107 - 1 to 107 - n , while the PON system is operating with the 0-system serving as an active system, and the 1-system serving as a standby system.
The 0-system transmission/reception section 101 a always monitors signals between the OLT 106 and ONUs 107 - 1 to 107 - n , and notifies a control section 110 of the OLT 106 of an abnormality upon detecting a signal abnormality. Upon reception of the abnormality notification, the control section 110 outputs a switching command to an SEL 105 of the OLT 106 to switch the transmission path from the 0-system to the 1-system. As a consequence, connection between the OLT 106 and the ONUs 107 - 1 to 107 - n is restored by using the 1-system optical transmission path.
Upon outputting the switching command to the SEL 105 , the control section 110 outputs switching commands to the ONUs 107 - 1 to 107 - n through the 1-system connection, i.e., the SEL 105 - 1 , 1-system transmission/reception section 101 b , photocoupler 102 b , and the 1-system transmission/reception sections 103 - 1 b to 103 - nb of the ONUs 107 - 1 to 107 - n . With this operation, the control sections 111 - 1 to 111 - n of the ONUs 107 - 1 to 107 - n control switching operation of the SELs 108 - 1 to 108 - n to restore the transmission paths to subscriber terminals 109 - 1 to 109 - n.
In each of the dual arrangements of the conventional PON systems shown in FIGS. 25 and 26 , however, even if a fault occurs in only the transmission/reception 103 - 1 a of the 0-system ONU 107 - 1 , which is part of the PON system, the overall PON system must be simultaneously switched from the 0-system to the 1-system in order to restore a path under communication. That is, switching is performed even for the ONUs 107 - 2 to 107 - n that are operating normally. As a result, the communication quality deteriorates due to short breaks and the like caused in this operation.
In each of the arrangements of the conventional PON systems shown in FIGS. 25 and 26 , the active and standby systems are physically discriminated from each other, and the standby system cannot be used until it is selected by the SEL 105 . In addition, the active system is switched to the standby system by only interchanging the physical transmission paths, and only the same connection as the preceding connection is restored.
A star type light subscriber transmission device using a star coupler is disclosed in Japanese Patent Laid-Open No. 05-153053 (reference 1). According to reference 1, a fault detection circuit and fault detection signal generation circuit are connected to the terminal on an N branching side of the star coupler having a branching of 2: N via an optical directional coupler. A first-station-side light subscriber transmission device is connected to one terminal of the branching side of the star coupler, and a fault detection signal extraction circuit and a second-station-side light subscriber transmission device are connected to the other terminal via an optical branching device. The first- and second-station-side light subscriber transmission devices are switched and controlled by a selection circuit which received the output signal from the fault detection signal extraction circuit.
A dual changeover system using a star coupler is disclosed in Japanese Patent Laid-Open No. 10-294753 (reference 2). According to reference 2, a phase difference calculation means calculates a reception phase difference between an active-system transmission/reception section and a standby-system transmission/reception section of a subscriber-side device while the reception states of the active-system transmission/reception section and standby-system transmission/reception section are normal. A pointer control means then calculates a standby-system transmission phase by using the calculated reception phase difference and the active-system transmission phase.
In references 1 and 2, there is no description about switching of only a virtual path having undergone a fault to the standby system, and there is provided no solution to the above problem associated with switching of normal virtual paths.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a protection switching method and apparatus for a PON system, which can easily switch only a path to be restored to a standby-system path without affecting communication through normal virtual paths in the PON system.
In order to achieve the above object, according to the present invention, there is provided a protection switching method for a passive optical network system including an optical line terminal for switching between a first active-system transmission/reception section and a first standby-system transmission/reception section by using a switch, a plurality of network units for selectively connecting second active-system transmission/reception sections and second standby-system transmission/reception sections to subscriber terminals upon switching the sections through selectors in the event of a communication abnormality, and transmission paths for star-connecting the second active-system transmission/reception sections to the first active-system transmission/reception section, and also star-connecting the second standby-system transmission/reception sections to the first standby-system transmission/reception section, comprising the steps of detecting a communication abnormality in at least one active-system virtual path established between the optical line terminal and the subscriber terminal through the transmission path and the network unit, and upon detection of a communication abnormality in the active-system virtual path, causing the switch to switch the transmission paths to establish a standby-system virtual path between the optical line terminal and the subscriber terminal serving as a communication partner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is block diagram showing a protection switching apparatus for a PON system according to the first embodiment of the present invention;
FIG. 2 is a block diagram showing virtual paths established between an OLT and subscriber terminals in the protection switching apparatus in FIG. 1 ;
FIG. 3 is a block diagram showing a normal established state of virtual paths between the OLT and a plurality of subscriber terminals in the protection switching apparatus in FIG. 1 ;
FIG. 4 is a block diagram for explaining the flows of ATM signals in the normal established state in FIG. 3 ;
FIG. 5 is a block diagram showing a state wherein an abnormality has occurred in a virtual path (VP 1 ) in the normal established state in FIG. 3 ;
FIG. 6 is a block diagram showing a state wherein a new virtual path (VP 2 a ) is established from the abnormal state in FIG. 5 ;
FIG. 7 is a block diagram showing the flows of ATM signals in the established state of the new virtual path (VP 2 a ) in FIG. 6 ;
FIG. 8 is a block diagram showing the operation of a selector of an ONU at the time of switching to the new virtual path (VP 2 a ) in FIG. 6 ;
FIG. 9 is a block diagram showing a protection switching apparatus for a PON system according to the second embodiment of the present invention;
FIG. 10 is a block diagram showing virtual paths established between an OLT and subscriber terminals in the protection switching apparatus in FIG. 9 ;
FIG. 11 is a block diagram showing the first virtual path setting example in the protection switching apparatus in FIG. 10 ;
FIG. 12 is a block diagram showing the second virtual path setting example in the protection switching apparatus in FIG. 10 ;
FIG. 13 is a block diagram showing the third virtual path setting example in the protection switching apparatus in FIG. 10 ;
FIG. 14 is a block diagram showing the fourth virtual path setting example in the protection switching apparatus in FIG. 10 ;
FIG. 15 is a block diagram showing a protection switching apparatus for a PON system according to the third embodiment of the present invention;
FIG. 16 is a block diagram showing a protection switching apparatus for a PON system according to the fourth embodiment of the present invention;
FIG. 17 is a block diagram showing virtual paths established between an OLT and subscriber terminals in the protection switching apparatus in FIG. 16 ;
FIG. 18 is a block diagram showing a normal established state of virtual paths between the OLT and a plurality of subscriber terminals in the protection switching apparatus in FIG. 16 ;
FIG. 19 is a block diagram showing the flows of ATM signals in the normal established state in FIG. 16 ;
FIG. 20 is a block diagram showing a state wherein an abnormality has occurred in a virtual path (VP 1 ) in the normal established state in FIG. 16 ;
FIG. 21 is a block diagram showing a state wherein a new virtual path (VP 2 a ) is established from the abnormal state in FIG. 20 ;
FIG. 22 is a block diagram showing the flows of ATM signals in the state wherein the new virtual path (VP 2 a ) is established in FIG. 21 ;
FIG. 23 is a block diagram showing the operation of a selector of each ONU at the time of switching to the new virtual path (VP 2 a ) in FIG. 21 ;
FIG. 24 is a block diagram showing the basic arrangement of a PON system;
FIG. 25 is a block diagram showing the first example of a conventional PON system having a dual arrangement; and
FIG. 26 is a block diagram showing the second example of a conventional PON system having a dual arrangement.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail below with reference to the accompanying drawings.
FIG. 1 shows a protection switching apparatus for a PON system according to the first embodiment of the present invention. Referring to FIG. 1 , an OLT 6 incorporates a switch 4 , 0-system transmission/reception section 1 a , and 1-system transmission/reception section 1 b.
The 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b detect the communication states of virtual paths established between the OLT 6 and subscriber terminals 91 to 9 n connected to ONUs (Optical Network Units) 71 to 7 n , and send warning signals to a control section 10 . The 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b are connected to different ports of the switch 4 . The switch 4 switches virtual paths to be established under the control of the control section 10 . The switch 4 and control section 10 constitute a virtual path establishment switching means.
Assume that virtual paths constitute an ATM (Asynchronous Transfer Mode) PON in this embodiment. Note that a virtual path is a bundle of virtual channels, and switching of connections using virtual channels can be executed in the same manner as described above.
The 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b are respectively connected to photocouplers 2 a and 2 b . The photocoupler 2 a is connected to 0-system transmission/receptions 31 a to 3 na of the ONUs 71 to 7 n through optical fibers 11 a to 1 na . That is, the ONUs 71 to 7 n are star-connected to the photocoupler 2 a (the 0-system transmission/reception section 1 a of the OLT 6 ). Likewise, the photocoupler 2 b is connected to 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n through optical fibers 21 b to 2 nb . That is, the ONUs 71 to 7 n are star-connected to the photocoupler 2 b (1-system transmission/reception section 1 b of the OLT 6 ).
The ONUs 71 to 7 n respectively include SELs 81 to 8 n for making connection to the subscriber terminals 91 to 9 n by switching from the 0-system transmission/receptions 31 a to 3 na to the 1-system transmission/receptions 31 b to 3 nb (or switching in the reverse direction) in accordance with switching request signals transmitted from the OLT 6 . Switching request signals from the OLT 6 are sent from the control section 10 to the ONUs 71 to 7 n through the optical fibers 11 a to 1 na or optical fibers 21 b to 2 nb at the time of virtual path switching control by the switch 4 .
The operation of the protection switching apparatus having the above arrangement will be described next, assuming that the 0-system and 1-system respectively serve as an active system and standby system. FIG. 2 shows a case wherein a virtual path is established to allow communication between the subscriber terminal 91 and the OLT 6 .
Referring to FIG. 2 , when the 0-system transmission/reception section 1 a of the OLT 6 is connected to the 0-system transmission/reception section 31 a of the ONU 71 through the photocoupler 2 a and optical fiber 11 a , a virtual path VP 1 a is established between the subscriber terminal 91 and the 0-system transmission/reception section 1 a of the OLT 6 in accordance with the setting of the switch 4 . When the 1-system transmission/reception section 1 b of the OLT 6 is connected to the 1-system transmission/reception section 1 b of the ONU 71 through the photocoupler 2 b and optical fiber 21 b , a virtual path VP 1 b is established between the subscriber terminal 91 and the 1-system transmission/reception section 1 b of the OLT 6 in accordance with the setting of the switch 4 .
In the case shown in FIG. 2 , the subscriber terminal 91 can communicate with either the 0-system transmission/reception section 1 a or the 1-system transmission/reception section 1 b of the OLT 6 .
Switching operation from an active-system virtual path under normal communication operation to a standby-system virtual path will be described next with reference to FIG. 3 .
Referring to FIG. 3 , the bold lines indicate established virtual paths VP 1 and VP 2 . The virtual path VP 1 is established by the following route: switch 4 —0-system transmission/reception section 1 a of the OLT 6 —photocoupler 2 a —optical fiber 11 a —0-system transmission/reception section 31 a of the ONU 71 —SEL 81 —subscriber terminal 91 . Communication is performed between the subscriber terminal 91 and the 0-system transmission/reception section 1 a of the OLT 6 through the virtual path VP 1 .
The virtual path VP 2 is established by the following route: switch 4 —0-system transmission/reception section 1 a of the OLT 6 —photocoupler 2 a —optical fiber 12 a —0-system transmission/reception section 32 a of the ONU 72 —SEL 82 —subscriber terminal 92 . Communication is performed between the 0-system transmission/reception section 1 a and the subscriber terminal 92 through the virtual path VP 2 .
Referring to FIG. 3 , therefore, the virtual path VP 1 takes charge of communication between the OLT 6 and the subscriber terminal 91 , and the virtual path VP 2 takes charge of communication between the OLT 6 and the subscriber terminal 92 .
In such a normal communication state, the switch 4 operates in the manner shown in FIG. 4 . Referring to FIG. 4 , ATM cell #1 to be transmitted to the ONU 71 is transmitted to the 0-system transmission/reception section 31 a of the ONU 71 through the switch 4 , 0-system transmission/reception section 1 a , photocoupler 2 a , and virtual path VP 1 . ATM cell #2 to be transmitted to the ONU 72 is transmitted to the 0-system transmission/reception section 32 a of the ONU 72 through the switch 4 , 0-system transmission/reception section 1 a , photocoupler 2 a , and virtual path VP 2 .
In this case, both ATM cells #1 and #2 pass through the 0-system transmission/reception section 1 a of the OLT 6 . In accordance with the values of headers H 1 and H 2 of ATM cells #1 and #2, the switch 4 outputs ATM cells #1 and #2 to the corresponding ports.
When an abnormality (e.g., disconnection) occurs in the virtual path VP 1 between the 0-system transmission/reception section 31 a of the ONU 71 and the photocoupler 2 a as indicated by an “X” in FIG. 5 in the above normal communication state, only a signal from the ONU 71 does not arrive at the 0-system transmission/reception section 1 a of the OLT 6 . The 0-system transmission/reception section 1 a of the OLT 6 therefore detects an abnormality in the communication state of the virtual path VP 1 , and sends a warning signal to the control section 10 .
Upon reception of the warning signal, the control section 10 controls the switch 4 to change the setting of the virtual path. With this operation, the switch 4 switches the virtual path VP 1 to the virtual path VP 1 a , as shown in FIG. 6 . That is, the virtual path VP 1 a is established by the following route: 1-system transmission/reception section 1 b of the OLT 6 —photocoupler 2 b —optical fiber 21 b— 1-system transmission/reception section 31 b of the ONU 71 . As a consequence, the communication between the OLT 6 and the ONU 71 is resumed.
At this time, the virtual path VP 2 is kept used for the communication between the OLT 6 and the ONU 72 without being affected.
FIG. 7 shows the flows of signals through the switch 4 at the time of switching from the virtual path VP 1 to the virtual path VP 1 a in FIG. 6 .
Referring to FIG. 7 , in accordance with the setting of a virtual path with respect to the switch 4 , ATM cell #1 to be transmitted to the ONU 71 is transmitted to the virtual path VP 1 a formed by the following route: switch 4 —1-system transmission/reception section 1 b of the OLT 6 —photocoupler 2 b —optical fiber 21 b . ATM cell #2 to be transmitted to the ONU 72 is transmitted to the virtual path VP 2 formed by the following route: switch 4 —0-system transmission/reception section 1 a of the OLT 6 —photocoupler 2 a —optical fiber 12 a– 1-system transmission/reception section 32 a of the ONU 72 .
In this case, in accordance with the values of the headers H 1 and H 2 added to ATM cells #1 and #2, ATM cells #1 and #2 are distributed to the corresponding ports of the switch 4 .
The operation of the SEL 81 of the ONU 71 at the time of the above switching from the virtual path VP 1 to the virtual path VP 1 a will be described next with reference to FIG. 8 .
Referring to FIG. 8 , the control section 10 transmits a switching request signal for the SEL 81 to the ONU 71 through the virtual path VP 1 a established by the control operation of the switch 4 . Upon reception of the switching request signal from the OLT 6 , the ONU 71 selects and connects the SEL 81 through the 1-system transmission/reception section 31 b , thus connecting the subscriber terminal 91 to the 1-system transmission/reception section 31 b through the SEL 81 .
With this operation, a signal from the 1-system transmission/reception section 31 b of the ONU 71 is transmitted to the subscriber terminal 91 through the SEL 81 . As a result, the communication between the OLT 6 and the subscriber terminal 91 is resumed through the virtual path VP 1 a.
FIG. 9 shows a protection switching apparatus for a PON system according to the second embodiment of the present invention. The same reference numerals as in FIG. 1 denote the same parts in FIG. 9 .
The arrangement of an OLT 6 in FIG. 9 is the same as that in FIG. 1 . In the OLT 6 , a 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b are connected to different ports of a switch 4 . The 0-system transmission/reception section 1 a of the OLT 6 is connected to a photocoupler 2 a and connected to 0-system transmission/receptions 31 a to 3 na of ONUs 71 to 7 n through the photocoupler 2 a and optical fibers 11 a to 11 na . The 1-system transmission/reception section 1 b of the OLT 6 is connected to a photocoupler 2 b and connected to 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n through the photocoupler 2 b and optical fibers 21 b to 2 nb.
In this connection arrangement, the 0-system transmission/reception section 1 a of the OLT 6 exchanges signals with the 0-system transmission/receptions 31 a to 3 na of the ONUs 71 to 7 n . The photocoupler 2 a branches an optical signal from the 0-system transmission/reception section 1 a into signals to the optical fibers 11 a to 11 na so as to transmit them to the 0-system transmission/receptions 31 a to 3 na in the ONUs 71 to 7 n . Likewise, the 1-system transmission/reception section 1 b of the OLT 6 exchange signals with the 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n . The photocoupler 2 b branches an optical signal from the 1-system transmission/reception section 1 b into signals to the optical fibers 21 b to 2 nb so as to transmit them to the 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n.
The ONUs 71 to 7 n respectively incorporate SELs 81 to 8 n as in the arrangement shown in FIG. 1 . The SELs 81 to 8 n select signals from the 0-system transmission/receptions 31 a to 3 na or 1-system transmission/receptions 31 b to 3 nb and output them to subscriber terminals 91 to 9 n . The 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b of the OLT 6 have the function of always monitoring signals. With this function, each of the 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b detects an abnormality in a transmission path and notifies the control section 10 of the abnormality.
Upon reception of the abnormality from the 0-system transmission/reception section 1 a or 1-system transmission/reception section 1 b , the control section 10 outputs a switching control signal to the switch 4 . Upon reception of the switching control signal from the control section 10 , the switch 4 discriminates header information, and outputs an input ATM cell to a corresponding port.
The ONUs 71 to 7 n respectively incorporate controls sections 111 to 11 n . The 0-system transmission/receptions 31 a to 3 na and 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n notify the controls sections 111 to 11 n of switching request signals transmitted from the OLT 6 through transmission paths. Upon notification of the switching request signals, the controls sections 111 to 11 n perform switching control on the SELs 81 to 8 n.
As shown in FIG. 10 , therefore, when a virtual path is to be established to exchange signals with the subscriber terminal 91 through the ONU 71 , a route running through the 0-system transmission/reception section 1 a of the OLT 6 , i.e., a virtual path VP 1 a , and a route running through the 1-system transmission/reception section 1 b of the OLT 6 , i.e., virtual path VP 1 b , can be selectively used.
With this arrangement, therefore, when any one of the transmission elements constituting the active-system virtual path fails, the standby-system virtual path is selected by switching the virtual paths at the switch 4 , thereby resuming the communication with the target subscriber through a transmission path that is physically different from the faulty path.
Since the 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b are connected to different ports of the switch 4 in the OLT 6 , the two virtual paths VP 1 a and VP 1 b can be set to have different bands. In addition, since the resources of the two systems, i.e., the 0-system and 1-system, can be selectively used, one of the systems through which an active virtual path is to be established can be arbitrarily determined. By using these features, flexible network design like that described below can be realized.
In the first example of this case, a standby-system virtual path having a band narrower than that of an active-system virtual path is prepared through one route, and the remaining band is used for services. By setting a limitation that minimum services are ensured in the event of a fault in this manner, the total band allocated to the physical resources of the 0-system and 1-system is effectively distributed. This makes it possible to use a broader band for services than in a case wherein the resources of only one system are fully used.
In the second example, since faults do not always occur in all virtual paths in operation at once, there is no need to always ensure a band for setting standby-system virtual paths for all the active-system virtual paths. That is, a given band is ensured as a common standby band for all virtual paths in operation, and is used for only a virtual path having undergone a fault to set a standby-system virtual path.
This makes it possible to broaden the band that can be used for services as compared with a case wherein a band is ensured for standby-system virtual paths in a one-to-one correspondence with all active-system virtual paths. If a band broader than the common standby-system band is required in case faults have occurred in a plurality of virtual paths at once, the band for virtual paths in normal operation is limited to ensure a necessary band for virtual paths.
In the third example, no band for setting standby-system virtual paths is ensured during normal operation, and a maximum band allowed for physical resources is used for services. A band for other normal virtual paths is limited in the even of a fault to ensure a band necessary for standby-system virtual paths, thus establishing standby-system virtual paths.
In the fourth example, a single system accommodates subscribers who require no dual protection and subscribers who requires dual protection.
The operation of the second embodiment having this arrangement will be described next. For the sake of simplicity, assume that the number of ONUs is four, i.e., n=4.
FIG. 11 shows an example of how a first virtual path is set. FIG. 11 shows a state wherein the virtual path VP 1 a is established for the ONU 71 by using the 0-system, and a virtual path VP 2 a is established for the ONU 72 . In this state, the OLT 6 exchanges signals with the subscriber terminals 91 and 92 through the virtual paths VP 1 a and VP 2 a . At this time, the SELs 81 and 82 of the ONUs 71 and 72 respectively select the 0-system transmission/reception sections 31 a and 32 a.
In addition, virtual paths VP 3 a and VP 4 a are respectively established for the ONUs 73 and 74 by using the 1-system. In this state, the OLT 6 exchanges signals with the subscriber terminals 93 and 94 through the virtual paths VP 3 a and VP 4 a . At this time, the SELs 83 and 84 of the ONUs 73 and 74 respectively select 1-system transmission/receptions 33 b and 34 b.
On the other hand, standby-system virtual paths VP 3 b and VP 4 b corresponding to the virtual paths VP 3 a and VP 4 a are set by using the 0-system. In addition, standby-system virtual paths VP 1 b and VP 2 b corresponding to the virtual paths VP 1 a and VP 2 a are set by using 1-system.
In a normal case, communication is performed by using the virtual paths VP 1 a , VP 2 a , VP 3 a , and VP 4 a . If faults occur in the respective virtual paths VP 1 a , VP 2 a , VP 3 a , and VP 4 a , the control section 10 of the OLT 6 instructs the switch 4 to switch to the standby-system virtual paths VP 1 b , VP 2 b , VP 3 b , and VP 4 b and reconnect them to the corresponding ONUs.
The control section 10 sends switching request signals for the SELs 81 and 82 to the 1-system transmission/reception sections 31 b and 32 b of the ONUs 71 and 72 by using the standby-system virtual paths VP 1 b and VP 2 b , respectively. At the same time, the control section 10 sends switching request signals for the SELs 83 and 84 to the 0-system transmission/reception sections 33 a and 34 a of the ONUs 73 and 74 by using the standby-system virtual paths VP 3 b and VP 4 b , respectively.
The transmission/reception sections 31 b , 32 b , 33 a , and 34 a of the ONUs 71 to 74 receive the switching request signals from the OLT 6 , and notify the control sections 111 to 114 of the signals. Upon reception of these notifications, the respective control sections 111 to 114 switch the SELs 81 to 84 to resume the communication with target subscriber terminals.
Assume that each of the 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b of the OLT 6 has a band of “100” (a band of “100” per system), and the bands are assigned as follows:
virtual path VP 1 a =40 virtual path VP 2 a =40 virtual path VP 3 a =40 virtual path VP 4 a =40 virtual path VP 1 b =10 virtual path VP 2 b =10 virtual path VP 3 b =10 virtual path VP 4 b =10
In this case, each of the subscriber terminals 91 to 94 can use only a band of “10” in the event of a fault, but can use a band of “40” in normal operation. That is, a band of “160 (=40×4)” can be used for services as a whole. Therefore, services can be provided beyond a band of “100” that is obtained by fully using one system in the conventional scheme, and protection against faults can be guaranteed.
The second virtual path setting example will be described next with reference to FIG. 12 . As in the first virtual path setting example, the virtual paths VP 1 a to VP 4 a are respectively set for the subscriber terminals 91 to 94 . In this state, a virtual path VP 6 is set to switch the virtual path VP 1 a or VP 2 a that has become abnormal. In addition, a virtual path VP 5 is set to switch the virtual path VP 3 a or VP 4 a that has become abnormal.
Assume that each of the 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b of the OLT 6 has a band of “100”, and the respective bands are assigned as follows:
virtual path VP 1 a =33 virtual path VP 2 a =33 virtual path VP 3 a =33 virtual path VP 4 a =33 virtual path VP 5 =33 virtual path VP 6 =33
In this case, in normal operation, the total band that can be used for services is “132 (=33×4)”. That is, services can be provided beyond a band of “100” that is obtained by fully using one system in the conventional scheme.
In this setting example, if one of the virtual paths VP 1 a and VP 2 a become abnormal, the virtual path can be restored by directly switching to the virtual path VP 6 . In addition, if both the virtual paths VP 1 a and VP 2 a become abnormal at once, the respective virtual paths are set again such that the subscriber terminals 91 to 94 share a band of “100” held by the 1-system transmission/reception section 1 b of the OLT 6 . With this operation, protection against faults can be guaranteed. The same applies to switching operation for the virtual paths VP 3 a and VP 4 a in the event of faults.
The third virtual path setting example will be described next with reference to FIG. 13 . As in the first virtual path setting example, the virtual paths VP 1 a to VP 4 a are set for the subscriber terminals 91 to 94 .
Assume that each of the 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b of the OLT 6 has a band of “100”, and the respective bands are assigned as follows:
virtual path VP 1 a =50 virtual path VP 2 a =50 virtual path VP 3 a =50 virtual path VP 4 a =50
In this case, in normal operation, the total band that can be used for services is “200 (=50×4)”. That is, services can be provided beyond a band of “100” that is obtained by fully using one system in the conventional scheme.
In this setting example, no band is set in advance to reset a virtual path when it becomes abnormal. Every time an abnormality occurs in a virtual path, the band that has been used by normal virtual paths is limited, and the surplus band is used to restore the abnormal virtual path. This makes it possible to guarantee protection against faults.
The fourth virtual path setting example will be described next with reference to FIG. 14 . As in the first virtual path setting example, the virtual paths VP 1 a to VP 4 a are set for the subscriber terminals 91 to 94 . Assume that there is no need to provide protection for only services given to the subscriber terminal 92 . Therefore, the ONU 72 requires only one transmission/reception section (1-system transmission/reception section 32 a is used in FIG. 14 ).
In this setting example, communication is performed by using the virtual paths VP 1 a , VP 2 a , VP 3 a , and VP 4 a in normal operation. When faults occur in the virtual paths VP 1 a , VP 3 a , and VP 4 a , except for the virtual path VP 2 a , the control section 10 of the OLT 6 instructs the switch 4 to switch to the standby-system virtual paths VP 1 b , VP 3 b , and VP 4 b so as to resume the communication with the target subscriber terminals.
In this case as well, active- and standby-system virtual paths can be set in arbitrary bands within the range of the maximum band held by the physical resources.
As described above, in the second embodiment, virtual paths are switched by the switch 4 without discriminating physically different systems between an active system and a standby system. Since this makes it possible to establish a standby-system path to a target ONU through physically different transmission paths, network design can be performed with a high degree of freedom. As a consequence, active-system virtual paths can be provided by efficiently using limited physical resources, and standby-system virtual paths can be flexibly prepared in accordance with services.
FIG. 15 shows a protection switching apparatus for a PON system according to the third embodiment of the present invention.
Referring to FIG. 15 , in an OLT 6 , transmission/reception sections 11 to 13 are connected to different ports of a switch 4 . The transmission/reception section 11 of the OLT 6 is connected to transmission/reception sections 311 a to 31 na of ONUs 711 to 71 n through a photocoupler 21 . The transmission/reception section 12 of the OLT 6 is connected to transmission/reception sections 321 a to 32 na of ONUs 721 to 72 n through a photocoupler 22 . The transmission/reception section 13 is connected to transmission/receptions 311 b to 31 nb of ONUs 711 to 71 n and transmission/reception sections 321 b to 32 nb of the ONUs 721 to 72 n through a photocoupler 23 .
In normal operation, virtual paths are set for subscriber terminals 911 to 91 n through the transmission/reception section 11 of the OLT 6 . In addition, virtual paths are set for subscriber terminals 921 to 92 n through the transmission/reception section 12 of the OLT 6 . It is taken for granted that these virtual paths rarely become abnormal at once. For this reason, every time an abnormality occurs in an active-system virtual path, a standby-system virtual path is set again by using the band held by the transmission/reception section 13 . That is, the transmission/reception sections 11 and 12 serve as 0-system transmission/reception sections, whereas the transmission/reception section 13 serves as a 1-system transmission/reception section.
With this arrangement, the single transmission/reception section 13 can provide protection for the ONUs 711 to 771 n and 721 to 72 n connected to the transmission/reception sections 11 and 12 in the OLT 6 . Note that the number of transmission/reception sections in the OLT 6 may be four or more, and the number of ONU groups may be three or more.
FIG. 16 shows a protection switching apparatus for a PON system according to the fourth embodiment of the present invention.
The fourth embodiment is a modification to the first embodiment. More specifically, control sections 111 to 11 n are additionally arranged in the ONUs 71 to 7 n in FIG. 1 , and the control sections 111 to 11 n perform selective control on SELs 81 to 8 n to switch 0-system transmission/receptions 31 a to 3 na and 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n . The arrangement of the remaining portion is the same as that in FIG. 1 . The same reference numerals as in FIG. 1 denote the same parts in FIG. 16 , and a description thereof will be omitted.
The operation of the protection switching apparatus having the above arrangement will be described below.
Referring to FIG. 17 , when a 0-system transmission/reception section 1 a of a OLT 6 is connected to the 0-system transmission/reception section 31 a of the ONU 71 through a photocoupler 2 a and optical fiber 11 a , a virtual path VP 1 a is established between a subscriber terminal 91 and the 0-system transmission/reception section 1 a of the OLT 6 in accordance with the setting of a switch 4 . When a 1-system transmission/reception section 1 b of the OLT 6 is connected to the 1-system transmission/reception section 31 b of the ONU 71 through a photocoupler 2 b and optical fiber 21 b , a virtual path VP 1 b is established between the subscriber terminal 91 and the 1-system transmission/reception section 1 b of the OLT 6 in accordance with the setting of the switch 4 .
In the case shown in FIG. 17 , the subscriber terminal 91 can communicate with both the 0-system transmission/reception section 1 a and 1-system transmission/reception section 1 b of the OLT 6 .
Switching operation from an active-system virtual path under normal communication operation to a standby-system virtual path will be described next with reference to FIG. 18 .
Referring to FIG. 18 , the bold lines indicate established virtual paths VP 1 and VP 2 . The virtual path VP 1 is established through the following route: switch 4 —0-system transmission/reception section 1 a of the OLT 6 —photocoupler 2 a —optical fiber 11 a —0-system transmission/reception section 31 a of the ONU 71 —SEL 81 —subscriber terminal 91 . Communication is performed between the 0-system transmission/reception section 1 a and the subscriber terminal 91 through the virtual path VP 1 . The virtual path VP 2 is established through the following route: switch 4 —0-system transmission/reception section 1 a of the OLT 6 —photocoupler 2 a —optical fiber 12 a —0-system transmission/reception section 32 a in an ONU 72 —SEL 82 —subscriber terminal 92 . Communication is performed between the 0-system transmission/reception section 1 a and the subscriber terminal 92 through the virtual path VP 2 .
In the case shown in FIG. 18 , therefore, the virtual path VP 1 takes charge of communication between the OLT 6 and the subscriber terminal 91 , and the virtual path VP 2 takes charge of communication between the OLT 6 and subscriber terminal 92 .
In a normal communication state shown in FIG. 18 , the switch 4 operates in the manner shown in FIG. 19 . Like FIG. 4 , FIG. 19 shows the flows of signals. More specifically, ATM cell #1 to be transmitted to the ONU 71 is transmitted to the 0-system transmission/reception section 31 a of the ONU 71 through the switch 4 , 0-system transmission/reception section 1 a , photocoupler 2 a , and virtual path VP 1 . ATM cell #2 to be transmitted to the ONU 72 is transmitted to the 0-system transmission/reception section 32 a of the ONU 72 through the switch 4 , 0-system transmission/reception section 1 a , photocoupler 2 a , and virtual path VP 2 .
In this case, both the ATM cells #1 and #2 pass through the 0-system transmission/reception section 1 a . In addition, the switch 4 has the function of outputting ATM cells #1 and #2 to corresponding ports of the switch 4 in accordance with the values of headers H 1 and H 2 of ATM cells #1 and #2.
Assume that in the normal communication state shown in FIG. 18 , an abnormality (e.g., disconnection) occurs in the virtual path VP 1 between the photocoupler 2 a and the 0-system transmission/reception section 31 a of the ONU 71 , as indicated by “X” in FIG. 20 . In this case, only a signal from the ONU 71 does not arrive at the 0-system transmission/reception section 1 a in the OLT 6 . The 0-system transmission/reception section 1 a of the OLT 6 detects the abnormality in the communication state of the virtual path VP 1 , and sends a warning signal to the control section 10 of the OLT 6 .
Upon reception of the warning signal from the 0-system transmission/reception section 1 a , the control section 10 controls the switch 4 to change the setting of virtual paths. As a consequence, the switch 4 switches the virtual path VP 1 to the virtual path VP 1 a , as shown in FIG. 21 . That is, the virtual path VP 1 a is established through the following route: 1-system transmission/reception section 1 b of the OLT 6 photocoupler 2 b —optical fiber 21 b– 1-system transmission/reception section 31 b of the ONU 71 . As a consequence, the communication between the OLT 6 and the ONU 71 can be resumed.
At this time, the virtual path VP 2 used for communication between the OLT 6 and the ONU 72 is kept used for the communication without being affected.
FIG. 22 shows the flows of signals through the switch 4 at the time of switching from the virtual path VP 1 to the virtual path VP 1 a.
Referring to FIG. 22 , in accordance with the setting of a virtual path for the switch 4 , ATM cell #1 to be transmitted to the ONU 71 is transmitted to the virtual path VP 1 a formed by the following route: switch 4 —1-system transmission/reception section 1 b in the OLT 6 —photocoupler 2 b —optical fiber 21 b . ATM cell #2 to be transmitted to the ONU 72 is transmitted to the virtual path VP 2 formed by the following route: switch 4 —0-system transmission/reception section 1 a of OLT 6 —photocoupler 2 a —optical fiber 12 a —0-system transmission/reception section 32 a of the OLT 6 .
In accordance with the values of the headers H 1 and H 2 added to the cells, these ATM cells #1 and #2 are distributed to the corresponding ports of the switch 4 .
The operation of the SEL 81 of the ONU 71 upon the above switching from the virtual path VP 1 to the virtual path VP 1 a will be described next with reference to FIG. 23 .
Referring to FIG. 23 , the control section 10 of the OLT 6 controls the switch 4 , and transmits a switching request signal to the ONU 71 through the virtual path VP 1 a established in the above manner. Upon reception of the switching request signal from the OLT 6 , the 1-system transmission/reception section 31 b of the ONU 71 notifies the control section 111 of the SEL switching signal.
Upon reception of the SEL switching signal, the control section 111 outputs a switching control signal to the SEL 81 of the ONU 71 . In accordance with the switching control signal from the ONU 71 , the SEL 81 switches the 0-system transmission/reception section 31 a of the ONU 71 to the 1-system transmission/reception section 31 b , and connects the subscriber terminal 91 to the 1-system transmission/reception section 31 b through the SEL 81 . With this operation, a signal from the 1-system transmission/reception section 31 b of the ONU 71 is transmitted to the subscriber terminal 91 through the SEL 81 . As a consequence, the communication between the OLT 6 and the subscriber terminal 91 can be resumed through the virtual path VP 1 a.
According to the fourth embodiment, since the control sections 111 to 11 n of the ONUs 71 to 7 n perform switching control on the 0-system transmission/reception section and 1-system transmission/reception section more reliably, communication between each subscriber terminal and the OLT can be reliably established, and a network can be flexibly designed.
In each embodiment described above, optical transmission paths constituted by the photocouplers 2 a and 2 b and optical fibers 11 a to 1 na and 21 b to 2 nb are used as transmission paths. However, the present invention is not limited to this, and may be applied to a case wherein a coaxial cable or another kind of metal line is used as a transmission path.
In each embodiment described above, an abnormality due to disconnection of the virtual path VP 1 is assumed to be an example of an abnormal communication state. However, in addition to this abnormal state, the present invention can be applied to abnormal states wherein, for example, one or a plurality of the 0-system transmission/receptions 31 a to 3 na and 1-system transmission/receptions 31 b to 3 nb of the ONUs 71 to 7 n has failed, the photocouplers 2 a and 2 b have failed, and SELs 81 to 8 n have failed.
In each embodiment described above, when the virtual path VP 1 is to be switched to the virtual path VP 1 a by using the ATM system, this switching operation is performed by distributing ATM cells #1 and #2 to ports of the switch 4 in accordance with the values of the headers H 1 and H 2 of the ATM cells #1 and #2. However, the present invention is not limited to this and can be applied to an STM (Synchronous Transfer Mode) PON system. In this case, a virtual path may be established by determining specific ports of the switch 4 for which data are to be destined in accordance with the time slots of frames output from the control section 10 in a predetermined cycle.
Each embodiment described above has been described in association with the occurrence of an abnormality in the virtual path VP 1 . Even if, however, an abnormality occurs in another portion, e.g., in the optical fiber 22 b before the establishment of a virtual path, a virtual path can be established by switching the switch 4 to allow communication between the OLT 6 and the subscriber terminal 92 .
In this case, when the 1-system transmission/reception section 1 b in the OLT 6 detects the abnormality in the optical fiber 22 b while the virtual path VP 2 shown in FIG. 21 is not established, and outputs a warning signal, the control section 10 controls the switch 4 to switch ports. With this operation, the virtual path VP 2 is established by the following route: switch 4 —0-system transmission/reception section 1 a of the OLT 6 —photocoupler 2 a —optical fiber 12 a —0-system transmission/reception section 32 a of the ONU 72 . At the same time, the 0-system transmission/reception section 32 a of the ONU 72 is selected by the SEL 82 and connected to the subscriber terminal 92 . This allows communication between the subscriber terminal 92 and the OLT 6 .
In each embodiment described above, virtual paths are switched in the event of an abnormality in one optical fiber, i.e., a transmission path of one system. However, the virtual paths between the OLT 6 and the ONUs 71 to 7 n can be simultaneously switched by the switch 4 .
In this case, when the 0-system transmission/receptions 31 a to 3 na of the ONUs 71 to 7 n simultaneously transmit warning signals indicating communication abnormalities, the control section 10 of the OLT 6 , which has received these warning signals, simultaneously switches the ports of the switch 4 to simultaneously switch the virtual paths from the active system between the OLT 6 and the ONUs 71 to 7 n to the standby system. In addition, when the ONUs 71 to 7 n , which have accessed signals distributed from the OLT 6 , simultaneously output warning signals, the control section 10 may simultaneously switch predetermined ports of the switch 4 upon reception of the signals.
As has been described above, in the protection switching method and apparatus for the PON system according to the present invention, only a path to be restored can be easily switched to a standby-system path without affecting communication through a normal virtual path in the PON system, and the communication can be continued. This makes it possible to easily switch virtual paths without causing any short break and the like in normal apparatuses.
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In a protection switching method for a passive optical network system, a communication abnormality is detected in at least one active-system virtual path established between an optical line terminal and a subscriber terminal through a transmission path and a network unit. When a communication abnormality is detected in an active-system virtual path, a switch is controlled to switch the transmission paths to establish a standby-system virtual path between the optical line terminal and the subscriber terminal as a communication partner. A protection switching apparatus for a passive optical network system is also disclosed.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 61/990,231 filed on May 8, 2014, the contents of which are incorporated by reference herein in its entirety.
TECHNICAL FIELD
This application relates to the area of anticancer therapeutics, more specifically, the application relates to the area of cancer immunotherapy. Specifically, the application discloses means of decreasing toxicity associated with immunotherapeutic interventions, while concurrently augmenting immune mediated inhibition of cancer growth and progression.
BRIEF SUMMARY
The current application teaches the use of a stimulator of immunity together with an antioxidant for augmentation of efficacy and reduction of toxicity associated with administration of said immune stimulator. In one embodiment, IL-2 is utilized as an immune stimulator, while intravenous ascorbic acid is utilized as an antioxidant. In another embodiment, TLR activation in combination with an antioxidant is employed for synergistic enhancement of immune response, as well as tumor cell killing. In one embodiment, administration of the TLR-7 agonist imiquimod is performed in combination with ascorbic acid at a concentration sufficient to induce antitumor effects. In another embodiment, an antioxidant is administered intravenously with imiquimod for protection of the endothelium from imiquimod mediated toxicity, while allowing immune enhancement.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is graph illustrating the synergistic reduction in tumor growth over time resulting from the administration of IL-2, ascorbic acid, and both as compared to saline.
DETAILED DESCRIPTION
The basis of cancer therapy is to identify/develop interventions that: a) selectively kill tumor cells while sparing non-malignant cells; b) prevent development of tumor-resistance; and c) act systemically to prevent relapse. Theoretically, immunotherapy of cancer would achieve all these aims. Selective killing of tumor cells has been demonstrated by a wide range of immune cells ranging from conventional CD8 T cells, gamma delta T cells, natural killer (NK) cells, natural killer T (NKT) cells and in some studies neutrophils. Other components of the immune system expressing tumor selectivity include complement factors and natural antibodies of the IgM isotype. Tumor resistance to immunotherapy, differs from resistance to chemotherapy, where expression of multiple drug resistance proteins actively pumps out cancer-toxic substances. One mechanism is downregulation of human leukocyte antigen (HLA) by tumor cells in response to T cell killing. The immune system conceptually overcomes this by the NK subset which preferentially kills cells with downregulated HLA. The other mechanism of tumor resistance from immunological attack is by mutating antigens that are being recognized. Given the promiscuous binding ability of T cell and B cell receptors to bind antigens, the cells could conceptually “mutate with the tumor” in order to recognize and kill cells with variant antigens. Immunological destruction of neoplasia is believed to occur at a systemic level and thus arises the possibility to inhibit metastasis and tumor recurrence, in part through induction of immunological memory.
The history of tumor immunotherapy begins with the work of William Coley who induced a systemic inflammatory/immune activation through administration of killed S. pyogenes and Serratia marcescens bacteria in patients with soft tissue sarcoma. The advent of molecular biology allowed for assessment of molecular signals associated with systemic immune activation. The cytokine tumor necrosis factor (TNF)-alpha was one of the molecular signals associated with anticancer efficacy of innate immune activators such as the Coley vaccine. Studies have demonstrated that TNF-alpha has the ability to induce profound death of cancer cells in vitro and in vivo in animal models, however human studies demonstrated unacceptable levels of toxicity. IL-2 was the next cytokine associated with immune activation that was tested. Originally termed T Cell Growth Factor (TCGF), IL-2 was demonstrated in early studies to endow human lymphocytes with ability to selectively kill tumor but not healthy control cells. Subsequent studies have demonstrated that cytotoxic activity was mediated through T cell and natural killer (NK) cells, whose activation requires stimulation of the IL-2 receptor, which can be accomplished in vivo with high doses of IL-2. Animal studies suggested that IL-2 has a short half-life of approximately 2 minutes after intravenous injection, and human half life was reported to be approximately an hour. Thus it was apparent that clinical use of IL-2 would be requiring repeated administration at high doses. Despite this pitfall, preclinical studies demonstrated highly potent anti-tumor effect. In 1985 Steven Rosenberg reported regression of established pulmonary metastasis, as well as various subcutaneous tumors by administration of IL-2. These data were highly promising due to the fact that tumor killing could be achieved systemically, and by activation of specific immune cells that could be identified in vivo as interacting with and inducing death of the tumor.
Early studies of IL-2 demonstrated impressive results in a subset of melanoma and renal cell cancer patients. Development of systemic autoimmunity to melanocytes, such as the occurrence of vitiligo during the treatment with systemic IL-2 was found to be predictive of response. These studies were expanded and eventually IL-2 received approval as the first recombinant immunotherapeutic drug by the FDA. There appears to be a dose response with IL-2 in that the doses that seem to be most effective are also associated with significant toxicity. The most significant cause of toxicity is vascular leak syndrome (VSL), manifested as fluid loss into the interstitial space, which is a result of increase vessel permeability. Additional effects include thrombocytopenia, elevated hepatic serum transaminases, hepatocyte necrosis, hypoalbuminemia, tissue and peripheral eosinophilia, and prerenal azotemia. It is one of the aims of the current application to overcome IL-2 associated toxicities by the concurrent administration of ascorbic acid.
Vascular leak syndrome (VLS) is considered to be the major dose-limiting adverse effect of IL-2 administration. In a meta-analysis of studies performed in metastatic renal cell carcinoma patients, objective responses were observed in 23% of patients, the majority of which lasted more than 10 years. Unfortunately, 65% of patients have to interrupt or stop therapy because of VLS. This syndrome is characterized by an increased extracellular fluid extravasation, hypotension, ascites, pulmonary edema, and hydrothorax, and clinically resembles the systemic inflammatory response syndrome (SIRS). Dermatological manifestations include erythrematous eruptions and mild papillary edema associated with burning and pruritus of the skin. Severe forms of VLS are associated with pulmonary or cardiac failure with approximately 1% of treated patients having lethal outcome. Typically the symptoms of VLS are treated by vasopressor therapy and judicious fluid replacement, such as with colloid solutions for their osmotic effects. Patients may also be treated with theophylline and terbutaline, for which clinical experience suggests a possible reduction of the severity and frequency of acute episodes.
At a cellular level it is well-known that VLS is associated with endothelial cell activation and increased with vascular permeability. Biopsies of patients receiving IL-2 revealed an increased expression of adhesion molecules such as ICAM and LFA-1. These proteins are known to promote granulocyte extravasation, however, such upregulation was not observed when IL-2 was added directly to endothelial cell cultures in vitro, suggesting the effect was mediated by other host components. Given that one of the main cellular targets of IL-2 is the T cells, which express two types of IL-2 receptor, it appears that the initial T cell activation is a major contributor to downstream inflammatory effect on endothelium subsequent to IL-2 administration. In an early study, Rosenberg's group established a murine model for quantifying VLS by administering radioactively iodinated albumin into mice receiving IL-2 and assessing radioactivity of tissues. In this model, increased gamma-counts are correlated with endothelial permeability and leakage of albumin into tissues. They found that administration of IL-2 to nude mice or mice that have been immune suppressed by radiation, cyclophosphamide, or steroids, was associated with markedly reduced or no vascular leakage. It is within the scope of the current application to decrease IL-2 mediated T cell induction of endothelial activation by administration of antioxidants, such as ascorbic acid. In one embodiment of the invention ascorbic acid is combined with effective amounts of high molecular weight hyaluronic acid to decrease toxicity of IL-2 and allow for higher IL-2 administration. In one embodiment of the invention a deficiency of nutrients or micronutrients is corrected by supplementation with effective amounts of cysteine, methionine, calcium, magnesium, copper, zinc, iron, molybdenum, and selenium.
It is possible that the process of LAK generation is involved in stimulation of VLS, as was suggested in a study using a similar system in which transfer of LAK along with administration of IL-2 led to more profound endothelial leakage as compared to either alone. Interestingly, in the same study it was shown that depletion of host lymphocytes reduced vascular leakage only in response to IL-2 alone, but not in response to IL-2 and LAK transfer. Other studies have shown that cells bearing the NK marker asialo-GM1 are associated with some of the IL-2 associated toxicities. Anderson et al showed that antiserum to asialo GM1 suppressed mortality, vascular leak syndrome, hepatic damage and reduced infiltration of pulmonary and hepatic vasculature by asialo GM1+ lymphocytes induced by IL-2 treatment. Depletion of the Asialo-GM1 bearing cells did not alter lymphoid hyperplasia, tissue infiltration by Lyt 2+ lymphocytes, tissue and peripheral eosinophilia, or thrombocytopenia. Interestingly, the antisera did not affect the anti-tumor efficacy of IL-2 therapy in BDF mice bearing the colon 38 adenocarcinoma. Thus it is possible that T cell and NK cell activation by the high dose IL-2 induces production of various cytokines, one example being TNF-alpha, which are known to induce endothelial cell activation locally, and systemically are mediators of SIRS. Given that antioxidants have been successfully used in the treatment of SIRS, it is within the scope of the current application to apply antioxidants to the treatment of IL-2 mediated toxicity.
Another event associated with IL-2 administration appears to be complement activation. The complement system is an enzymatic cascade of about 30 circulating proteins, primarily generated by the liver that cause inflammation and amplification of a various immune responses. The complement system can be activated through the classical (antibody mediated) pathway, alternative pathways (antibody-independent), or through the mannose-binding lectin pathway, all of which lead to formation of the membrane attack complex which causes cell lysis through generation of pores in the cell membrane. In a clinical study of metastatic renal cancer patients receiving IL-2 via a 24-hour i.v. infusion at a daily dose of 3×10(6) U/m 2 for 5 consecutive days, the classical complement pathway components C3 and C4 were measured daily during IL-2 infusion, and after its interruption. IL-2 administration was associated with a significant decrease in both C3 and C4 levels, which normalized on average 5 days after the end of IL-2 infusion. Another study associated presence of VLS in patients receiving IL-2 with complement activation as assessed by levels of C3a and the classical complement component C4a. In this study levels of C3a were as elevated as those found in septic and burn patients. Another study examining 23 cancer patients undergoing therapy with interleukin-2 and lymphokine-activated killer cells demonstrated 3-fold elevations of C3a desArg concentrations by the 8th day of therapy with concentrations of C4a desArg also being elevated by the end of therapy. Associated with activation of the complement system was an increase in the neutrophil cell-surface expression of complement receptor Type 1 and complement receptor Type 3.
This interesting dependence on T cells for complement activation bridges the studies demonstrating that T cells are necessary for both endothelial activation and VLS associated with IL-2 administration. A study by Vachino et al showed that cancer patients had pretreatment similar to control plasma levels of C3a, Ba, Bb, and SC5b-9. Post-IL-2 treatment C3a levels where shown to be increased on average of 15.6-fold. The Ba and Bb proteins, which belong to the alternatively complement activation pathway were augmented 8.0- and 5.0-fold, respectively, subsequent to IL-2 treatment. The plasma levels of the effector complement complex, SC5b-9, was increased 5.0-fold and the plasma C4d and iC3b concentrations increased 4.8- and 2.9-fold, respectively, after treatment. To show the involvement of patient lymphocytes in complement activation, the investigators found that cells expressing the T cell marker CD3 had increased surface expression of anti-C3c and anti-SC5b-9 by 6.2-fold and 5.1-fold, respectively after IL-2 therapy. The authors concluded that the T cells were participating in the IL-2 induced complement activation. This was also demonstrated in that increased concentration of the inflammatory protein C-reactive protein (CRP) was found post-IL-2 therapy, and that the T cells bound CRP. T cell bound CRP was capable of activating the alternative complement pathway. Therapeutically, it was demonstrated that administration of the complement inhibitor C1 esterase inhibitor was capable of reducing IL-2 induced hypotension and complement activation in patients.
Various components of the complement cascade have been demonstrated to directly activate endothelial cells, with endothelial cell activation not only causing lymphocyte and neutrophil extravasation, but also thrombosis by the upregulation of tissue factor. C5a is a byproduct of complement activation that has been demonstrated to induce endothelial cell activation and permeability. This protein is also a major effector in systemic inflammatory disorders and antibodies to it are being assessed clinically for this condition with some efficacy signals and suppression of endothelial activation published. The complement effector complex SC5b-9 was demonstrated in vitro to induce endothelial cell activation via stimulating expression of the Response Gene to Complement (RGC)-32, which in turn activates CDC2 and the AKT pathway. Jeffrey Platt's group demonstrated that complement activation is associated with induction of IL-1, which in turn stimulates endothelial cells expression of E-selectin, intracellular adhesion molecule-1, vascular cell adhesion molecule-1, Ikappa-Balpha, interleukin (IL)-1alpha, IL-1beta, IL-8, and tissue factor. Thus in the cascade of IL-2 induced VLS, it appears that T cell activation may be associated with complement activation, and complement activation, in turn, stimulates endothelial cell activation. One of the cardinal features of endothelial cell activation is stimulation of the clotting cascade.
According to the emerging picture that VLS has many common elements with SIRS, one of the common features is development of local thrombocyte and coagulation system activation. Innate immune response possesses the ability to locally marginalize pathogens by stimulation of clotting and consequent sequestration. However, this process becomes pathological when it occurs at a systemic level, such as SIRS or VLS. Upregulation of tissue factor expression was previously noted on endothelial cells from animals treated with IL-2. Expression of this protein is known to cause activation of the clotting cascade, as well as stimulate inflammatory processes. Hack et al demonstrated activation of the contact system of coagulation proteins by showing that patients on IL-2 therapy had degradation of factor XII and prekallikrein. Reductions in these proteins appeared not due to protein leakage into the interstitial space, since their levels were still significantly lower, i.e., 80 and 50%, respectively, when corrected for albumin decreases. Thus it appears that non-specific activation of the coagulation system, and a resulting potential for thrombosis, occur as a result of IL-2 treatment. Given the inherently pro-thrombotic state of many cancer patients, it is theoretically possible that IL-2 therapy may have thrombotic complications, which indeed have previously been reported.
Granulocyte activation and tissue infiltration are hallmarks of systemic immune/inflammatory activation. In a study of 4 patients on IL-2, granulocytes became activated following IL-2 treatment with mean peak elastase/alpha 1-antitrypsin (E alpha 1 A) and lactoferrin values of 212 (SEM=37) and 534 (SEM=92) ng ml-1 respectively occurring 6 h after the IL-2. Activation of the complement cascade was evidenced by a dose dependent elevation of peak C3a values on day 5 of IL-2. The authors found that there was a significant correlation between C3a levels and the degree of hypotension during the first 24 h after IL-2 (r=0.91) and parameters of capillary leakage such as weight gain and fall in serum albumin (r=0.71). The authors concluded that activation of PMN initiates endothelial cell damage which subsequently leads to activation of the complement cascade. Another study showed that neutrophils of patients on IL-2 therapy expressed both phenotypic (up-regulation of CD11b/CD18 adhesion receptor expression) and functional (hydrogen peroxide and hypochlorous acid production) evidence of potent neutrophil activation.
Gut bacterial translocation is associated with chronic inflammatory states such as heart failure and mucositis, and acute states such as sepsis or GVHD, is translocation of bacterial flora into systemic circulation. Interestingly, IL-2 toxicity is associated with an interference with the gut flora and inflammation. In a recent study, 51 male rats were randomized to receive rIL-2 by intraperitoneal injection at doses (IU) of 10(5) (n=15), 10(4) (n=8), 10(3) (n=8) or 10(2) (n=8) twice daily, or a saline bolus (n=12). After 5 days, ileal histomorphology was assessed and the mesenteric lymph node complex was cultured. Results showed that colonisation of mesenteric lymph nodes with Escherichia coli occurred in all rats treated with 10(5) IU of rIL-2, and in 62%, 37% and 12% of rats treated with decreasing doses of rIL-2. No translocation was observed in control animals. An increase in submucosal lymphatics and occasional mucosal disruption was seen only in the group receiving 10(5) IU. These data show that rIL-2 promotes bacterial translocation and suggests a mechanism that may fuel high-dose rIL-2 toxicity in humans. Given the potent effects seen clinically with homeostatically-induced lymphocyte activation, and the recent findings that T cell homeostatic proliferation appears to be associated with gut flora translocation, it may be possible that tumor suppressive activity of IL-2 may be highly dependent on the gut flora, thus possibly explaining inter-patient variation.
Numerous studies have demonstrated that oxidative stress modifies endothelial cells in a manner that preferentially activates the complement cascade. The involvement of the mannose-binding lectin and the lectin complement pathway (LCP) in promoting complement activation by endothelial cells post oxidative stress was shown in studies using hypoxic (24 hours; 1% O(2))/reoxygenated (3 hours; 21% O(2)) human endothelial cells. Using iC3b deposition as a marker of complement activation, it was shown that N-acetyl-D-glucosamine or D-mannose, but not L-mannose, blocked activation, suggesting that oxidative stress upregulates the mannose dependent pathway. This was also demonstrated using mannose binding lectin deficient serum, as well as antibodies to mannose binding lectin. Furthermore C3 deposition was found in ischemic areas in rats that experienced cardiac ischemia reperfusion injury, a known inducer of oxidative stress.
It is documented that a scurvy-like condition occurs in a renal cell carcinoma patient treated with IL-2. The patient presented with acute signs and symptoms of scurvy (perifollicular petechiae, erythema, gingivitis and bleeding). Serum ascorbate levels were significantly reduced to almost undetectable levels during the treatment with IL-2. Although the role of ascorbic acid (AA) hyper-supplementation in stimulation of immunity in healthy subjects is controversial, it is well established that AA deficiency is associated with impaired cell mediated immunity. This has been demonstrated in numerous studies showing that deficiency of this vitamin suppresses T cytotoxic responses, delayed type hypersensitivity, and bacterial clearance. Additionally, it is well-known that NK activity, which mediates IL-2 anti-tumor activity, is suppressed during conditions of AA deficiency. Thus it may be that while IL-2 therapy on the one hand is stimulating T and NK function, the systemic inflammatory syndrome-like effects of this treatment may actually be suppressed by induction of a negative feedback loop. This negative feedback loop with IL-2 therapy was successfully overcome by work using low dose histamine to inhibit IL-2 mediated immune suppression, which led to the “drug” Ceplene (histamine dichloride) receiving approval as an IL-2 adjuvant for treatment of AML. Given the deficiency in endogenous ascorbic acid levels after IL-2 administration, the application seeks to overcome this deficit by prophylactically dosing the patient with ascorbic acid prior to, as well as concurrently with, and subsequently after immunotherapy.
The concept of AA deficiency subsequent to IL-2 therapy was reported previously by another group. Marcus et al evaluated 11 advanced cancer patients suffering from melanoma, renal cell carcinoma and colon cancer being on a 3 phase immunotherapeutic program consisting of: a) 5 days of i.v. high-dose (10(5) units/kg every 8 h) interleukin 2, (b) 6½ days of rest plus leukapheresis; and (c) 4 days of high-dose interleukin 2 plus three infusions of autologous lymphokine-activated killer cells. Mean plasma ascorbic acid levels were normal (0.64+/−0.25 mg/dl) before therapy. Mean levels dropped by 80% after the first phase of treatment with high-dose interleukin 2 alone (0.13+/−0.08 mg/dl). Subsequently plasma ascorbic acid levels remained severely depleted (0.08 to 0.13 mg/dl) throughout the remainder of the treatment, becoming undetectable (less than 0.05 mg/dl) in eight of 11 patients during this time. Importantly, blood pantothenate and plasma vitamin E remained within normal limits in all 11 patients throughout the phases of therapy, suggesting the hypovitaminosis was specific for AA. Strikingly, responders (n=3) differed from nonresponders (n=8) in that plasma ascorbate levels in the former recovered to at least 0.1 mg/dl (frank clinical scurvy) during Phases 2 and 3, whereas levels in the latter fell below this level. Similar results were reported in another study by the same group examining an additional 15 patients. The hypothesis that prognosis was related to AA levels is intriguing because of the possibility of higher immune response in these patients, however this has not been tested.
The main cause of VSL is increased permeability of the endothelium. Regardless of if the initiating cause is T cell activation, complement, and/or oxidative stress, the effector mechanism of VLS is alteration of endothelial cell function. In SIRS the endothelium is also the main effector causing lethality. Methods by which these cells are altered by both SIRS and IL-2 include: a) endothelial cell apoptosis, b) upregulation of adhesion molecules, and c) increased procoagulant state.
It was shown that in vitro administration of AA led to reduction of TNF-alpha induced endothelial cell apoptosis. The effect was mediated in part through suppression of the mitochondria-initiated apoptotic pathway as evidenced by reduced caspase-9 activation and cytochrome c release. Another study examined 34 patients with NYHA class III and IV heart failure who received AA or placebo treatment. AA treatment (2.5 g administered intravenously and 3 days of 4 g per day oral AA) resulted in reduction in circulating apoptotic endothelial cells in the treated but this was not observed in the placebo control group. Various mechanisms for inhibition of endothelial cell apoptosis by AA have been proposed including upregulation of the anti-apoptotic protein bcl-2 and the Rb protein, suppression of p53, and increasing numbers of newly formed endothelial progenitor cells.
AA has been demonstrated to reduce endothelial cell expression of the adhesion molecule ICAM-1 in response to TNF-alpha in vitro in human umbilical vein endothelial (HUVEC) cells (HUVEC). By reducing adhesion molecule expression, AA suppresses systemic neutrophil extravasation during sepsis, especially in the lung. Other endothelial effects of AA include suppression of tissue factor upregulation in response to inflammatory stimuli, an effect expected to prevent the hypercoaguable state. Furthermore, ascorbate supplementation has been directly implicated in suppressing endothelial permeability in the face of inflammatory stimuli, which would hypothetically reduce vascular leakage. Given the importance of NF-kappa B signaling in coordinating endothelial inflammatory changes, it is important to note that AA at pharmacologically attainable concentrations has been demonstrated to specifically inhibit this transcription factor in endothelial cells. Several pathways of inhibition have been identified including reduction of i-kappa B phosphorylation and subsequent degradation, and suppression of activation of the upstream p38 MAPK pathway. In vivo data in support of eventual use in humans has been reported showing that administration of 1 g per day AA in hypercholesterolemic pigs results in suppression of endothelial NF-kappa B activity, as well as increased eNOS, NO, and endothelial function. In another porcine study, renal stenosis was combined with a high cholesterol diet to mimic renovascular disease. AA administered i.v. resulted in suppression of NF-kappa B activation in the endothelium, an effect associated with improved vascular function.
The possibility that IL-2 therapy induces a state of systemic inflammation similar to SIRS has been discussed previously. One of the fundamental questions is whether AA actually has beneficial effects on the process of systemic inflammation. A mouse study demonstrated that after challenge with the bacteria Klebsiella pneumonia to induce a sepsis-like state, a 3-fold higher mortality is observed in ascorbate-deficient animals compared to controls. Another study hyper-supplemented animals with AA by administration of 10 mg/kg AA intravenously before induction of sepsis. IV AA treated animals had a 50% survival while only 19% of control animals survived. Other studies demonstrated that hyper-supplementation with AA resulted in better outcomes in sepsis-associated hypoglycemia, microcirculatory abnormalities, and blunted endothelial responsiveness in animal models.
Randomized clinical trials have been performed in septic patients using AA and vitamin E, which demonstrated superior outcomes, as well as reduction in parameters of oxidative stress. To date we know of one study in the recent history that assessed AA alone in patients with systemic inflammation. The investigators examined burn patients with >30% of their total body surface area affected. Patients were administered intravenous AA i.v. (66 mg/kg/hr for 24 hours, n=19) or received only standard care (controls, n=18). AA treatment resulted in statistically significant reductions in 24 hr total fluid infusion volume, and fluid retention (indicative of vascular leakage). Perhaps most striking was the decrease in the need for mechanical ventilation: the treated group required an average of average of 12.1±8.8 days, while the control group required 21.3±15.6 days. Given that numerous inflammatory markers associated with VLS are also found in SIRS and severe burn patients, the possibility is presented that AA may exert some beneficial effects on IL-2 therapy, both from the reduction of toxicity perspective, as well as from the stimulation of efficacy. Given the similarity between immunotherapy associated toxicity and SIRS, and given the ability to inhibit SIRS by administration of antioxidants, the current application teaches the use of antioxidants as a means of decreasing toxicities associated with immunotherapy, particularly, IL-2 administration.
Example
Female C57/BL6 mice are administered 5×10 5 B16 melanoma cells (American Type Culture Collection (Manassas, Va.)) cells subcutaneously into the hind limb flank. Mice are divided into groups of 12 mice per group as follows: a) saline administered intravenously, 200 microliters once every two days; b) IL-2 administered intravenously at 1000 IU every two days; c) ascorbic acid administered at 50 mg intravenously every second day; and d) ascorbic acid administered together with IL-2 intravenously every second day. Intravenous administration was performed into the tail vein. Tumor growth was assessed every 3 days by two measurements of perpendicular diameters by a caliper, and animals were sacrificed when tumors reached a size of 1 cm in any direction. Tumor volume was calculated by the following formula: (the shortest diameter 2 × the longest diameter)/2. As observed in FIG. 1 , a synergistic decrease of tumor growth was observed in the combination of IL-2 and intravenous ascorbic acid.
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The current application teaches methods and compositions useful for the treatment of cancer through administration of an antioxidant together with an immune stimulator at concentrations sufficient to augment antitumor immunity while simultaneously preventing inhibition of T cell function as a result of tumor secreted oxidative stress. Compositions such as toll like receptor agonists in combination with antioxidants are disclosed. In further embodiments, the application teaches the use of antioxidants to prevent immunotherapy associated oxidative stress, of which, one manifestation is vascular leak syndrome. In one specific embodiment, the application teaches the use of intravenous ascorbic acid as a means of reducing IL-2 associated toxicity.
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This application claims benefits of Japanese Application No. 2008-277714 filed in Japan on Oct. 29, 2008, the contents of which are incorporated by this reference.
BACKGROUND OF THE INVENTION
The present invention relates generally to an imaging optical system lending itself to imaging apparatus using imaging devices such as CCDs or CMOSs, and more particularly to an imaging apparatus equipped with such an imaging optical system.
Surveillance cameras, cameras mounted on interphones, and on-board cameras are now gaining popularity. For instance, the on-boards cameras are being used as visual identification cameras plus higher sensor cameras used for detecting white lines, and keeping watch over swerving from lanes, obstacles, and drivers.
Optical systems used with these cameras require a fisheye optical system having a half angle of view of, e.g., about 80° or greater for the purpose of making the visible angle of view wide thereby eliminating or reducing blind spots. There is also mounting demand for an imaging optical system that is not only compact but also works for cost reductions. Such imaging optical systems having a half angle of view of the order of 80° are known from Patent Publications 1, 2, 3 and 4.
Patent Publication 1: JP(A) 2002-244031 Patent Publication 2: JP(A) 2005-227426 Patent Publication 3: JP(A) 2006-259704 Patent Publication 4: JP(A) 2007-101920
However, the imaging optical system set forth in Patent Publication 1 has a long whole length relative to its focal length, and so goes against the reductions of general size, and especially diametrical size. Patent Publication 2 shows imaging optical systems, most of which comprise five singles lens and are hard to decrease in size. Patent Publication 2 also discloses an imaging optical system comprising four single lenses; however, it has a long whole length relative to its focal length, and so goes against the reductions of general size, and especially diametrical size. For the imaging optical system set forth in Patent Publication 3, lenses having large aspheric biases are used for correction of aberrations, and so fabrication costs are on the increase. The imaging optical system disclosed in Patent Publication 4 is susceptible of cost rises because of using two or more glass lenses.
Having been made with such problems in mind, the present invention has for its one object to provide an imaging optical system that works more in favor of size reductions and cost reductions while making sure a wide angle of view and optical performance. Another object of the invention is to provide an imaging apparatus incorporating such an imaging optical system.
SUMMARY OF THE INVENTION
According to the invention, the above object is accomplishable by the provision of an imaging optical system consisting of, in order from its object side, a front lens group of negative refracting power and a rear lens group of positive refracting power, characterized in that when a lens component is defined by a lens body having only two surfaces: an object side surface and an image side surface in contact with air on an optical axis,
said front lens group comprises, in order from its object side, a first lens component concave on its image side and having negative refracting power and a second lens component concave on its image side and having negative refracting power,
said rear lens group comprises, in order from its object side, a third lens component convex on its object side and having positive refracting power and a fourth lens component having positive refracting power,
an aperture stop is located between said third lens component and said fourth lens component,
the sum of the total number of lens components in said front lens group and the total number of lens components in said rear lens group is 4, and
said third component comprises a plastic positive lens that includes an aspheric surface and satisfies the following conditions (1-1) and (1-2):
19<ν3<29 (1-1)
1.59<n3<1.80 (1-2)
where
ν 3 is the Abbe constant of said plastic positive lens in said third lens component, and
n 3 is the d-line refractive index of said plastic positive lens in said third lens component.
In general, an imaging optical system having a wide angle of view relies upon a retrofocus type optical system that comprises, in order from its object side, a front lens group of negative refracting power and a rear lens group of positive refracting power.
To obtain a wide angle of view with such an optical system, the focal length of the whole optical system must be shortened. To this end, the negative refracting power of the front lens group having negative refracting power must be increased to bring the principal point position of the whole optical system near to an image plane side. And aberrations occurring from such arrangement must be corrected by properly configuring the rear lens group of positive refracting power; however, as the positive refracting power increases, it renders spherical aberrations likely to grow large.
The imaging optical system must be made compact when the associated camera is mounted on interphones or motor cars. To this end, both the front and the rear lens group must have large absolute values of refracting power.
Therefore, the imaging optical system of the invention is constructed of, in order from its object side, a front lens group of negative refracting power and a rear lens group of positive refracting power. The front lens group is made up of, in order from its object side, two lens components: a first lens component that is concave on its image side and has negative refracting power and a second lens component that is concave on its image side and has negative refracting power, and the rear lens group is built up of, in order from its object side, two lens components: a third lens component that is convex on its object side and has positive refracting power and a fourth lens component that has positive refracting power, with an aperture stop located between the third and the fourth lens component.
This arrangement ensures that an axial bundle that transmits through the front lens group of negative refracting power and diverges out is condensed onto the rear lens group of positive refracting power. The refracting power of each lens group is shared by two lens components, working for reductions of aberrations and making sure the angle of view, although the lens group is composed of fewer lenses. The stronger the degree of the convergence of the axial bundle by the lens group of positive refracting power, the more it works in favor of wider angles of view and size reductions.
An ordinary retrofocus type imaging optical system is likely to produce chromatic aberration of magnification. Especially with an imaging optical system having a wider angle of view, large chromatic aberration of magnification is likely to occur at the first and the second lens component where the position of incidence of off-axis light rays is far away from an optical axis.
To correct the chromatic aberration of magnification occurring at two such lens components, it is preferable to reduce as much as possible the Abbe constant of the positive lens in the third lens component, thereby canceling out the chromatic aberration of magnification produced at the first and the second lens component.
Condition (1-1) defines the preferable Abbe constant of the positive lens in the third lens component. Avoiding being in excess of the upper limit of condition (1-1) works in favor of making sure the function of canceling out the chromatic aberration of magnification occurring at the first and the second lens component. As the lower limit of condition (1-1) is not reached, any preferable plastic material is not available for aspheric lens material: only glass or other materials less likely to be processed into aspheric shape are available.
With the arrangement having a wider angle of view, the positive refracting power of the positive lens in the third lens component is likely to grow large. On the other hand, the use of glass lenses goes against cost reductions. In the invention, therefore, this positive lens is configured as a plastic aspheric lens that favors correction of spherical aberrations, and reliance is on the material that is easily processed into an aspheric shape.
Condition (1-2) defines the preferable refractive index of the positive lens in the third lens component for the purpose of making sure optical performance. Avoiding being short of the lower limit of condition (1-2) makes sure that refractive index so that the third lens component can have sufficient positive refracting power and the amount of an aspheric bias can easily be minimized, working for correction of spherical aberrations, size reductions, and making sure brightness. As the upper limit of condition (1-2) is exceeded, any preferable plastic material is not available for aspheric lens material: only glass or other materials less likely to be processed into aspheric shape are available.
Thus, the invention provides an imaging optical system that works more in favor of making sure a wider angle of view and optical performance, size reductions, and cost reductions.
More preferably in the invention as described above, one or two or more of the following requirements should be satisfied.
It is preferable that the first lens component is a single lens.
It is preferable that the second lens component is a single lens.
It is preferable that the third lens component is a single lens.
It is preferable that the fourth lens component is a single lens.
This works more in favor of the slimming down of each lens component, and cost reductions.
More preferably for size reductions and cost reductions, the first, the second, the third and the fourth lens components should be all single lenses.
It is preferable that the lens located in the first lens component and nearest to the object side is a glass lens, and that the second, the third, and the fourth lens component comprises a plastic lens.
The glass lens located in the first lens component and nearest to the object side is less vulnerable to flaws irrespective of whether or not a transparent member for protecting the imaging optical system is located more on the object side than the first lens component. And if an aspheric surface is located in the second, the third, and the fourth lens component and that aspheric surface is formed by the lens surface of a plastic lens, it then works more for improvements in optical performance while processing costs are slashed.
For the front lens group it is preferable to satisfy the following condition (2):
0.45< fa/|f 12|<0.65 (2)
where
f 12 is the focal length of the front lens group, and
fa is the focal length of the whole imaging optical system.
For the purpose of preventing more the occurrence of chromatic aberration of magnification at the first, and the second lens component, it is effective to make small the effective diameter of the first, and the second lens component. It is thus preferable that for the purpose of properly determining the position of an entrance pupil and making small the effective diameter of the first, and the second lens component, the combined system of the first and second lens components has negative refracting power capable of satisfying condition (2).
Avoiding being short of the lower limit of condition (2) makes sure the front lens group has negative refracting power, working for size reductions of the imaging optical system. Avoiding being in excess of the upper limit of condition (2) keeps the negative refracting power of the front lens group on a proper level, working for reductions of chromatic aberration of magnification.
For the second lens component it is preferable to satisfy the following condition (3):
0.2< fa/|f 2|<0.45 (3)
where
f 2 is the focal length of the second lens component, and
fa is the focal length of the whole imaging optical system.
The second lens component is smaller than the first lens component in terms of the effective diameter; even when the negative refracting power of the second lens component is increased, chromatic aberration of magnification occurring there is not as large as that at the first lens component. For the purpose of allowing the front lens group to have sufficient negative refracting power and reducing the size of the imaging optical system, therefore, it is preferable for the second lens component to have negative refracting power in such a way as to satisfy condition (3).
Avoiding being short of the lower limit of condition (3) can make sure the second lens component has sufficient negative refracting power, working in favor of size reductions. Avoiding being in excess of the upper limit of condition (3) keeps the negative refracting power of the second lens component on a proper level, so that the occurrence of chromatic aberration of magnification at the second lens component per se can easily be prevented.
For the third lens component it is preferable to satisfy the following condition (4):
0.2< fa/f 3<0.33 (4)
where
f 3 is the focal length of the third lens component, and
fa is the focal length of the whole imaging optical system.
For the purpose of correcting chromatic aberration of magnification occurring at the first, and the second lens component, it is for the third lens component to have positive refracting power in such a way as to satisfy condition (4).
Avoiding being short of the lower limit of condition (4) makes sure the third lens component has positive refracting power, working more in favor correction of chromatic aberrations occurring at the front lens group. Avoiding being in excess of the upper limit of condition (4) prevents the refracting power of the third lens component from growing excessive, working more in favor of prevention of overcorrection of chromatic aberration of magnification, and reducing spherical aberrations.
For the second, and the third lens component it is preferable to satisfy the following conditions (5) and (6):
1.2< R 4 /fa< 4 (5)
2.0< R 5 /fa< 5.0 (6)
where
R 4 is the paraxial radius of curvature of the image side surface of the second lens component,
R 5 is the paraxial radius of curvature of the object side surface of the third lens component, and
fa is the focal length of the whole imaging optical system.
Condition (5) defines the preferable paraxial radius of curvature of the image side surface of the second lens group with respect to the focal length of the whole imaging optical system.
Avoiding being short of the lower limit of condition (5) makes it easy to reduce the negative refracting power of the second lens component, working more in favor of reducing chromatic aberration of magnification. Avoiding being in excess of the upper limit of condition (5) makes it easy for the second lens component to have negative refracting power, working for size reductions of the imaging optical system.
Condition (6) defines the preferable paraxial radius of curvature of the object side surface of the third lens component with respect to the focal length of the whole imaging optical system.
Avoiding being short of the lower limit of condition (6) makes it easy to keep the positive refracting power of the third lens component on a proper level, making it easy to prevent overcorrection of chromatic aberration of magnification, and reduce spherical aberrations. Avoiding being in excess of the upper limit of condition (6) makes sure the third lens component has positive refracting power, working for correction of chromatic aberration of magnification produced at the first, and the second lens component.
For the first lens component it is preferable to satisfy the following condition (7):
0.6<( R 1+ R 2)/( R 1 −R 2)<2.5 (7)
where
R 1 is the paraxial radius of curvature of the object side surface of the first lens component, and
R 2 is the paraxial radius of curvature of the image side surface of the first lens component.
Avoiding being short of the lower limit of condition (7) prevents the object side surface of the first lens component from turning to a concave surface having a small paraxial radius of curvature, working for reductions of coma. Avoiding being in excess of the upper limit of condition (7) prevents the vertex of the object side surface of the first lens component from jutting out toward the object side, working for the slimming down of the imaging optical system.
For the second lens component it is preferable to be in such a shape as to satisfy the following condition (8):
0.6<( R 3+ R 4)/( R 3 −R 4)<1.3 (8)
where
R 3 is the paraxial radius of curvature of the object side surface of the second lens component, and
R 4 is the paraxial radius of curvature of the image side surface of the second lens component.
Avoiding being short of the lower limit of condition (8) facilitates preventing coma from occurring at the object side surface of the second lens component. Avoiding being in excess of the upper limit of condition (8) makes it easy for the second lens component to have negative refracting power, working for size reductions. It also facilitates reducing the negative refracting power of the first lens component, leading to reductions of chromatic aberration of magnification.
For the third lens component it is preferable to have a double-convex shape that satisfies the following condition (9):
−0.6<( R 5+ R 6)/( R 5 −R 6)<0.1 (9)
where
R 5 is the paraxial radius of curvature of the object side surface of the third lens component, and
R 6 is the paraxial radius of curvature of the image side surface of the third lens component.
Avoiding being short of the lower limit of condition (9) makes sure the image side surface of the third lens component has positive refracting power, working for making sure the third lens component has refracting power, and reducing spherical aberrations, and avoiding being in excess of the upper limit of condition (9) makes sure the object side surface of the third lens component has positive refracting power, working for correction of off-axis aberrations produced at the front lens group.
For the fourth lens component it is preferable to being in such a shape as to satisfy the following condition (10):
0.5<( R 8+ R 9)/( R 8 −R 9)<1.2 (10)
where
R 8 is the paraxial radius of curvature of the object side surface of the fourth lens component, and
R 9 is the paraxial radius of curvature of the image side surface of the fourth lens component.
Avoiding being short of the lower limit of condition (10) prevents the object side surface of the fourth lens component from turning to a convex surface having a small radius of curvature, facilitating prevention of the occurrence of off-axis aberrations. Alternatively, it makes sure the image side surface of the fourth lens component has positive refracting power, thereby spacing the exit pupil far away from the image plane. Avoiding being in excess of the upper limit of condition (10) prevents the radius of curvature of the image side convex surface from getting too small, facilitating prevention of the occurrence of spherical aberrations, etc.
More preferably, two or more of the above requirements should be satisfied at the same time.
When the imaging optical system is equipped with a focusing mechanism, each requirement is set upon focusing on the longest distance.
For more reliable advantages, the lower and upper limits of each condition should be narrowed down to the following values.
The lower and upper limits of condition (1-1) should be set at 22, more preferably 24, and 27.5, more preferably 27.1, respectively.
The lower and upper limits of condition (1-2) should be set at 1.60, more preferably 1.61, and 1.70, more preferably 1.65, respectively.
The lower and upper limits of condition (2) should be set at 0.50, more preferably 0.55, and 0.64, more preferably 0.63, respectively.
The lower and upper limits of condition (3) should be set at 0.25, more preferably 0.3, and 0.43, more preferably 0.4, respectively.
The lower and upper limits of condition (4) should be set at 0.25, more preferably 0.28, and 0.31, more preferably 0.3, respectively.
The lower and upper limits of condition (5) should be set at 1.25, more preferably 1.28, and 3, more preferably 2, respectively.
The lower and upper limits of condition (6) should be set at 2.5, more preferably 2.6, and 3.5, more preferably 3.2, respectively.
The lower and upper limits of condition (7) should be set at 0.8, more preferably 1.0, and 1.5, more preferably 1.3, respectively.
The lower and upper limits of condition (8) should be set at 0.8, more preferably 1.0, and 1.2, more preferably 1.1, respectively.
The lower and upper limits of condition (9) should be set at −0.5, more preferably −0.45, and −0.1, more preferably −0.25, respectively.
The lower and upper limits of condition (10) should be set at 0.6, more preferably 0.65, and 1.1, more preferably 1.0, respectively.
The invention also provides an imaging apparatus comprising an imaging optical system and an imaging device that is located on the image side of that imaging optical system and has an imaging plane, wherein said imaging optical system is any one of the above imaging optical systems.
The inventive imaging optical systems as described above may be used for imaging apparatus such as on-board cameras, surveillance cameras, digital cameras, digital video cameras, and small-format cameras mounted on cellular phone, personal computers, etc.
The taking half angle of view is from 70° to 100° inclusive.
The imaging apparatus equipped with the inventive imaging optical system is capable of taking images over a wide angle of view albeit being of small-format size. With a taking half angle of view of 70° or greater, the inventive imaging apparatus would be convenient in surveillance cameras or like other applications. Moreover, the imaging apparatus having a taking half angle of view of 80° or greater would be move convenient. When it comes to the imaging apparatus having a taking half angle of view of greater than 100°, the first lens component is likely to grow bulky for the purpose of making sure an optical path. That is, the taking half angle of view is preferably less than 100°, and more preferably less than 95°.
According to the invention, it is possible to provide an imaging optical system that works for size reductions and cost reductions while keeping a wide angle of view and optical performance as desired. It is further possible to provide an imaging apparatus incorporating such an imaging optical system.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is illustrative in section of the optical system according to Example 1.
FIG. 2 is illustrative in section of the optical system according to Example 2.
FIG. 3 is illustrative in section of the optical system according to Example 3.
FIG. 4 is a diagram indicative of various aberrations of the optical system according to Example 1 upon focusing at infinity.
FIG. 5 is a diagram indicative of various aberrations of the optical system according to Example 2 upon focusing at infinity.
FIG. 6 is a diagram indicative of various aberrations of the optical system according to Example 3 upon focusing at infinity.
FIG. 7 is illustrative in section of one embodiment of the lens assembly incorporating the imaging optical system according to the invention.
FIG. 8 is an exploded, schematic view of the lens assembly shown in FIG. 7 .
FIG. 9 is illustrative of a resilient member: FIGS. 9( a ) and 9 ( b ) are a front and a side view, respectively.
FIG. 10 is illustrative of how the resilient member is displaced.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
The inventive imaging lens is now explained with reference to Examples 1, 2 and 3. Sectional views of the lens arrangements of Examples 1, 2 and 3 are shown in FIGS. 1 , 2 and 3 . Throughout the drawings, the front lens group is indicated by Gf, the rear lens group by Gb, the aperture stop by S, the cover glass by C, and the imaging plane of a light receptor array by I. The plane-parallel plate shown is the cover glass C for protecting the imaging plane of the imaging device, and coated on its surface with an infrared cut coating.
The optical systems of Examples 1, 2 and 3 according to the invention are now explained.
FIG. 1 is illustrative in section of the optical system according to Example 1.
As shown in FIG. 1 , the imaging optical system of Example 1 is made up of, in order from its object side, the front lens group Gf of negative refracting power and the rear lens group Gb of positive refracting power.
The front lens group Gf is made up of, in order from its object side, a negative meniscus lens that is the first lens component concave on its image side and a negative meniscus lens that is the second lens component concave on its image side.
The rear lens group Gb is made up of, in order from its object side, a double-convex positive lens that is the third lens component, the aperture stop S, and a double-convex positive lens that is the fourth lens component.
Six aspheric surfaces are used: two at both surfaces of the negative meniscus lens on the image side of the front lens group Gf, two at both surfaces of the double-convex positive lens on the object side of the rear lens group Gb, and two at both surfaces of the double-convex positive lens on the image side of the rear lens group Gb.
FIG. 2 is illustrative in section of the optical system according to Example 2.
As shown in FIG. 2 , the imaging optical system of Example 2 is made up of, in order from its object side, the front lens group Gf of negative refracting power and the rear lens group Gb of positive refracting power.
The front lens group Gf is made up of, in order from its object side, a negative meniscus lens that is the first lens component concave on its image side and a negative meniscus lens that is the second lens component concave on its image side.
The rear lens group Gb is made up of, in order from its object side, a double-convex positive lens that is the third lens component, the aperture stop S, and a double-convex positive lens that is the fourth lens component.
Five aspheric surfaces are used: one at the image side surface of the negative meniscus lens in the front lens group Gf, two at both surfaces of the double-convex positive lens on the object side of the rear lens group Gb, and two at both surfaces of the double-convex positive lens on the image side of the rear lens group Gb.
FIG. 3 is illustrative in section of the optical system according to Example 3.
As shown in FIG. 3 , the imaging optical system of Example 3 is made up of, in order from its object side, the front lens group Gf of negative refracting power and the rear lens group Gb of positive refracting power.
The front lens group Gf is made up of, in order from its object side, a negative meniscus lens that is the first lens component concave on its image side and a negative meniscus lens that is the second lens component concave on its image side.
The rear lens group Gb is made up of, in order from its object side, a double-convex positive lens that is the third lens component, the aperture stop S, and a double-convex positive lens that is the fourth lens component.
Five aspheric surfaces are used: one at the image side surface of the negative meniscus lens on the image side of the front lens group Gf, two at both surfaces of the double-convex positive lens on the object side of the rear lens group Gb, and two at both surfaces of the double-convex positive lens on the image side of the rear lens group Gb.
Set out below are numerical data about Examples 1, 2 and 3. In those numerical data about Examples 1, 2 and 3, r is the radius of curvature of each lens surface, d is a lens thickness or air spacing, nd and νd are the refractive index and Abbe constant of each lens on an air calculated basis, f is a focal length, Fno is an F-number, ω is a taking half angle of view (°), BF is a back focus on an air calculated basis, and L is the whole length of each optical system (and filters are given on an air calculated basis, too).
In the numerical examples of the inventive imaging optical system given below, there are imaging optical systems obtained which are as low as about 2.8 in the F-number, and give images of high quality, albeit having a half angle of view of as large as about 80°, and are made up of fewer lenses, ensuring compactness and low costs.
In each numerical example, the first lens component is a single lens of glass; the second lens component is a single lens of plastics having aspheric surfaces on one or both sides; the third lens component is a single lens of plastics having aspheric surfaces on one or both sides; and the fourth lens component is a single lens of plastics having aspheric surfaces on both sides.
The aperture stop is of constant aperture size.
Focusing is not implemented because of reliance on pan focusing.
When x is an optical axis provided that the direction of travel of light is positive and y is a direction orthogonal to the optical axis, aspheric configuration is given by:
x =( y 2 /r )/[1+{1−( K+ 1)( y/r ) 2 } 1/2 ]+A 4 y 4 +A 6 y 6 +A 8 y 8 +A 10 y 10 +A 12 y 12
where r is a paraxial radius of curvature, K is a conical coefficient, and A 4 , A 6 , A 8 , A 10 and A 12 are the fourth-, the sixth-, the eighth-, the tenth-, and the twelfth-order aspheric coefficient, respectively.
Numerical Example 1
Unit mm
Surface Data
Surface No.
r
d
nd
νd
1
105.901
0.90
1.59551
39.22
2
4.703
1.92
3 (Aspheric Surface)
200.200
1.00
1.52542
55.78
4 (Aspheric Surface)
2.203
1.22
5 (Aspheric Surface)
4.365
2.50
1.61421
25.60
6 (Aspheric Surface)
−8.078
1.35
7 (Stop)
∞
0.99
8 (Aspheric Surface)
9.957
1.70
1.52542
55.78
9 (Aspheric Surface)
−1.795
1.54
10
∞
1.22
1.54424
70.87
11
∞
0.57
Image Plane
∞
Aspheric Data
3rd Surface
K = 0.000, A4 = 8.14140E−04, A6 = −5.94490E−05,
A8 = 8.99370E−06, A10 = −4.53820E−07
4th Surface
K = −0.207, A4 = 2.13520E−02, A6 = −4.09430E−03,
A8 = 1.56860E−03, A10 = −2.76370E−04
5th Surface
K = 0.000, A4 = 2.53890E−02, A6 = −6.73870E−04,
A8 = −2.68480E−05, A10 = 3.39730E−05
6th Surface
K = 0.000, A4 = 3.23180E−02, A6 = −1.27060E−02,
A8 = 6.06850E−03, A10 = −7.80470E−04
8th Surface
K = −4.251, A4 = −1.45770E−03, A6 = −2.38580E−02,
A8 = 1.53520E−02, A10 = −2.84950E−03
9th Surface
K = −1.068, A4 = 3.66160E−03, A6 = 1.62510E−03,
A8 = −3.56370E−03, A10 = 9.65320E−04
Various Data
f
1.44
ω
82.92°
Fno
2.8
BF
2.90
L
14.48
Numerical Example 2
Unit mm
Surface Data
Surface No.
r
d
nd
νd
1
221.315
0.70
1.59551
39.24
2
6.730
1.53
3
104.036
1.01
1.52540
56.25
4 (Aspheric Surface)
1.851
1.83
5 (Aspheric Surface)
3.768
2.41
1.60687
27.00
6 (Aspheric Surface)
−9.074
1.55
7 (Stop)
∞
0.80
8 (Aspheric Surface)
270.889
1.85
1.52540
56.25
9 (Aspheric Surface)
−1.568
1.37
10
∞
1.22
1.51633
64.14
11
∞
0.63
Image Plane
∞
Aspheric Data
4th Surface
K = −2.350, A4 = 3.75044E−02, A6 = −6.23094E−03,
A8 = 1.15508E−03, A10 = −9.17640E−05
5th Surface
K = −1.402, A4 = 7.60399E−03, A6 = 2.52234E−04,
A8 = 1.26458E−04
6th Surface
K = 19.012, A4 = 5.48350E−03, A6 = 5.22567E−03,
A8 = −1.11470E−03, A10 = 2.06491E−04
8th Surface
K = 9.620, A4 = −7.44277E−02, A6 = 2.84804E−02,
A8 = −4.15675E−02, A10 = 1.60270E−02, A12 = 1.61498E−08
9th Surface
K = −1.045, A4 = −1.36746E−02, A6 = −4.38406E−03,
A8 = −2.36040E−04, A10 = −3.62638E−04
Various Data
f
1.43
ω
82.92°
Fno
2.8
BF
2.81
L
14.49
Numerical Example 3
Unit mm
Surface Data
Surface No.
r
d
nd
νd
1
110.364
0.90
1.59551
39.22
2
4.779
1.86
3
73.494
1.09
1.52542
55.78
4 (Aspheric Surface)
2.267
1.27
5 (Aspheric Surface)
4.035
2.48
1.61421
25.60
6 (Aspheric Surface)
−9.784
1.33
7 (Stop)
∞
0.96
8 (Aspheric Surface)
9.761
1.75
1.52542
55.78
9 (Aspheric Surface)
−1.773
1.54
10
∞
1.22
1.54424
70.87
11
∞
0.51
Image Plane
∞
Aspheric Data
4th Surface
K = −0.183, A4 = 3.09360E−02, A6 = −1.11430E−02,
A8 = 2.43500E−03, A10 = −2.78760E−04
5th Surface
K = 0.000, A4 = 2.47030E−02, A6 = −3.87920E−03,
A8 = 8.59140E−04, A10 = −4.31590E−05
6th Surface
K = 0.000, A4 = 2.12200E−02, A6 = −4.90370E−03,
A8 = 4.04250E−03, A10 = −5.85790E−04
8th Surface
K = −1.357, A4 = −3.58710E−02, A6 = 1.55290E−02,
A8 = −1.27140E−02, A10 = 5.55860E−03
9th Surface
K = −1.065, A4 = −1.07310E−02, A6 = 8.73970E−03,
A8 = −6.53620E−03, A10 = 1.46580E−03
Various Data
f
1.49
ω
82.92°
Fno
2.8
BF
2.86
L
14.50
FIGS. 4 , 5 and 6 are diagrams for various aberrations of the imaging optical systems according to Examples 1, 2 and 3. Given for spherical aberrations and chromatic aberration of magnification are values at 587.6 nm (d-line; a solid line), 435.8 nm (g-line; a one dotted line) and 656.3 nm (C-line; a dotted line). For astigmatism, a solid line is indicative of the sagittal image surface, and a dotted line is indicative of the meridional image surface.
Tabulated below are the values of conditions (1) to (10) in Examples 1, 2 and 3.
Condition
Example 1
Example 2
Example 3
(1-1)
25.60
27.00
25.60
(1-2)
1.61421
1.60687
1.61421
(2)
0.623
0.596
0.611
(3)
0.342
0.398
0.332
(4)
0.292
0.303
0.299
(5)
1.524
1.292
1.532
(6)
3.021
2.630
2.727
(7)
1.093
1.063
1.091
(8)
1.022
1.036
1.064
(9)
−0.298
−0.413
−0.416
(10)
0.694
0.988
0.693
One example of the lens assembly using one of the above examples is now explained with reference to FIGS. 7 and 8 .
FIG. 7 is illustrative in section and schematic of one embodiment of the lens assembly using the imaging optical system according to the invention, and FIG. 8 is an exploded, perspective view of that embodiment.
In FIGS. 7 and 8 , reference numeral 1 stands for a lens barrel in which an area M is provided to receive lenses. The lens barrel 1 is built up of an annular form of peripheral wall made of a plastic or metallic material, and includes openings 1 a and 1 b open toward the object side (the left side of the paper) and the image side (the right side of the paper). The openings 1 a and 1 b here are called the ingoing opening 1 a and the outgoing opening 1 b , respectively. Light on the object side enters the lens barrel 1 through the ingoing opening 1 a , and leaves the lens barrel 1 through the outgoing opening 1 b , arriving at an imaging device (not shown). The inner peripheral surface of the lens barrel 1 having the area M to receive lenses is provided with steps t 1 to t 5 that provide inner peripheral wall surfaces (seat surfaces) L 1 to L 4 to receive lenses, which have diameters D 1 to D 4 phased down toward the outgoing opening 1 b.
Reference numeral 2 stands for a flare stop wall provided at the outgoing opening 1 b . This flare stop wall 2 is integrally joined to the outgoing opening 1 b , and includes a through-hole 2 a in which the central portion including the optical axis of the lenses located on the image side (as will be described later) is exposed.
Reference numeral 3 stands for the first lens component that is forced through the ingoing opening 1 a in the lens barrel 1 and received on the seat surface L 1 so that it is fixed by caulking K to the lens barrel 1 . The first lens component 3 has an outer peripheral surface 3 a fitted over the seat surface L 1 , and has a front outer edge provided with a bevel 3 b over which a deformed site of the lens barrel 1 goes during caulking.
Reference numeral 4 is indicative of the second lens component that is located adjacent to the first lens component 3 and on the seat surface L 2 . The front surface of the second lens component 4 is provided with an engagement 4 a that is in surface contact with the rear surface of the first lens component 3 via the flare stop.
Reference numeral 5 is indicative of the third lens component that is located adjacent to the second lens component 4 and on the seat surface L 3 . As with the second lens component 4 , the front surface of the third lens component 5 is provided with an engagement 5 a that is in surface contact with the rear surface of the second lens component 4 via the flare stop.
Reference numeral 6 is indicative of the fourth lens component that is located adjacent to the third lens component 5 and on the seat surface L 4 . The front surface of this fourth lens component 6 is provided with an engagement 6 a that is in surface contact with the rear surface of the third lens component 5 via an aperture stop. The fourth lens component 6 is located such that the vertex of the image side lens juts out of the through-hole 2 a in the flare stop wall 2 . The second 4 ; the third 5 , and the fourth lens component 6 may be provided on its outer peripheral surface with one or two or more cut faces.
Reference numeral 7 is indicative of a sheet-form flare stop located between the first 3 and the second lens component 4 ; 8 a sheet-form flare stop located between the second 4 and the third lens component 5 ; and 9 a sheet-form aperture stop located between the third 5 and the fourth lens component 6 . The aperture stop 9 limits the diameter of an axial bundle, and the flare stops 7 and 8 play a role of shielding off inessential light components of object side light incident from the first lens component 3 : off-axis marginal rays leading to coma and stray light responsible for ghosts. The stop 7 , 8 , and 9 is constructed of a polyester or other sheet, and matted or otherwise coated with a black coating for the purpose of preventing incidence or reflection of inessential light. Alternatively, the stop 7 , 8 , and 9 may be provided by coating the end face of the associated lens component with a black coating.
Reference numeral 10 is a seal member exemplified by an O-ring. This seal member 10 is held between a recess 3 c provided in the rear, outer edge of the first lens component 3 and the step (step surface) t 2 of the lens barrel 1 to keep a space between them airtight.
Reference numeral 11 is indicative of a resilient member (leaf spring) interposed between the fourth lens component 6 and the flare stop wall 2 . As the first lens component 3 is forced onto the seat surface L 1 , that resilient member 11 produces repulsive force to bring the end faces of the lens components 3 , 4 , 5 and 6 in resilient contact (support) with each other to position them within the lens barrel 1 . The resilient member comprises a thin annular base 11 a that is larger than the through-hole 2 a in the flare stop wall 2 and has an opening large enough to receive the central convex portion (optical function surface) of the fourth lens component 6 , and a plurality of arms (of sheet shape) 11 b supported at and integrally joined to the outer edge of the annular base 11 a in a cantilevered manner.
FIGS. 9( a ) and 9 ( b ) are a front and a side view of the resilient member 11 , and FIG. 10 is illustrative of how the resilient member is displaced.
Each arm 11 b is provided at its root with a bent 11 b 1 (bending line) that bends the arm itself slightly in the thickness direction. As the resilient member 11 produces repulsive force, the end of the arm 11 b is prevented from extending outwardly in the diametrical direction and contacting the seat surface L 5 , so that the arm can serve its own function more effectively.
Reference numeral 12 is indicative of a stopper provided on the inner surface of the flare stop wall 2 . As there are external vibrations such as unexpected impacts introduced into the fourth lens component 6 , the edge e of the through-hole 2 a in the flare stop wall 2 engages the outside of the fourth lens component 6 in the diametrical direction before doing the outer surface of the fourth lens component 6 . In other words, the stopper 12 prevents lens flaws in the effective diameter, which may possibly be caused by contact of the lens with the edge e of the through-hole 2 a . For the stopper 12 , an annular convex portion or a plurality of spaced projections may be used.
When the imaging optical system according to the invention is assembled into the lens assembly, the resilient member 11 is first fitted in the lens barrel 1 . Then, the fourth lens component 6 , the aperture stop 9 , the third lens component 5 , the flare stop 8 , the second lens component 4 , and the flare stop 7 are located in order. Then, the first lens component 3 together with the seal member 10 is forced into the ingoing opening 1 a in the lens barrel 1 and, thereafter, the lens barrel 1 is caulked to fix the first lens component 3 onto the seat surface L 1 . Here, the resilient member 11 produces repulsive force so that the first lens component 3 allows the second 4 , the third 5 and the fourth lens component 6 to be in resilient contact with each other. It is thus possible to position the respective lens components precisely along the direction of the optical axis c in the lens barrel 1 with no need of excessive work.
The shape of the resilient member 11 may optionally be varied provided that it can resiliently support the respective lens components along the optical axis. Alternatively, a rubber member may be used in place of the leaf spring.
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An imaging optical system consists of, in order from its object side, a front lens group of negative refracting power, and a rear lens group of positive refracting power. A lens component is defined by a lens body having only two surfaces: an object side surface and an image side surface in contact with air on an optical axis. The front lens group comprises, in order from its object side, a first lens component concave on its image side and having negative refracting power, and a second lens component concave on its image side and having negative refracting power. The rear lens group comprises, in order from its object side, a third lens component convex on its object side and having positive refracting power, and a fourth lens component having positive refracting power. The sum of the total number of lens components in the front lens group and the total number of lens components in the rear lens group is 4. The third component comprises a plastic positive lens that includes an aspheric surface and satisfies the following conditions (1-1) and (1-2):
19<ν3<29 (1-1)
1.59<n3<1.80 (1-2)
where ν 3 is the Abbe constant of the plastic positive lens in the third lens component, and n 3 is the d-line refractive index of the plastic positive lens in the third lens component.
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This is a continuation of application Ser. No. 242,775 filed Mar. 11, 1981, now U.S. Pat. No. 4,347,069 issued Aug. 31, 1982.
TECHNICAL FIELD
This invention relates to apparatuses for supplying fluids to rotating tubes such as is done in the manufacture of optical fiber preforms.
BACKGROUND OF THE INVENTION
Some industrial processes call for the introduction of fluids into rotating tubes. In many such situations it is desirable, if not essential, that this be done without ambient matter becoming entrained with the fluid as it flows from a stationary conduit into the rotating tube.
For example, in constructing preforms from which optical fibers may be drawn, vapors of materials such as SiCl 4 , GeCl 4 , BCl 3 and POCl 3 are entrained in an oxidizing carrier gas such as oxygen. The vapor stream is then drawn through a stationary conduit and into a rotating glass preform tube. In order to inhibit the vapor stream from leaking to ambient atmosphere, and ambient air from entering and thereby contaminating the vapor stream, a rotary seal has been provided at the junction of the stationary and rotary tubes. This seal has been provided by locating an end portion of one of the tubes within an end portion of the other tube and positioning one or more resilient O-rings or washers between the two tubes. However, this arrangement has been less than satisfactory since at least one of the tubes is constantly rubbing against the resilient O-rings causing them to become heated and to wear out. Structural deterioration of the O-rings, of course, soon leads to leakage which is aggravated whenever, as here, there is a pressure differential between the fluid stream and ambient. Furthermore, in such highly controlled situations as optical fiber preform manufacture even a very slight leak can create severe problems. For example, a leak PPM to ambient surrundings can endanger personnel since the vapor stream is toxic. Such leakage also alters the rate of vapor stream flow into the preform which rate must be precisely controlled. Conversely, an ingress of ambient air will also alter the flow rate as well as contaminate the vapor stream with water vapor.
Thus, it is desirable to provide improved apparatuses for supplying a rotating tube with fluid uncontaminated with ambient air such as is done in fabricating optical fiber preforms. It is this task to which the present invention is primarily directed.
In one form of the invention a protective end member is provided for a rotatable tubular member. The protective end member has a housing formed with a bore therein of greater inside dimensions than the outside dimensions of the tubular member for receiving an end of the tubular member without making contact with it. Means are provided within the housing for permitting the introduction of fluid into the interior of the tubular member. Means are also provided within the housing for permitting the introduction of a purging fluid into the housing bore at a pressure in excess of ambient pressure to prevent contaminating materials from being introduced into the interior of the tubular member from the ambient atmosphere.
In another form of the invention apparatus is provided for supplying fluid to a rotary tube substantially uncontaminated with ambient air. The apparatus comprises an end cap having an open ended bore in which an end portion of the tube may be rotatably positioned. First conduit means extend into the end cap through which fluid may be fed into the rotary tube. Second conduit means communicate with the end cap bore through which a purge fluid may be fed into and at least partially through the bore to the exterior of the end cap.
In still another form of the invention apparatus is provided for inhibiting ambient air from entering an end of a rotatable tube into which a stream of fluid is to be delivered. The apparatus comprises an end cap adapted to be positioned closely about an end portion of the rotatable tube so as to form a generally annular channel therebetween which communicates with the exterior of the end cap. The end cap defines a first passage through which a first stream of fluid may flow into the rotatable tube and a second passage through which a second stream of fluid may flow into and through the annular channel to the exterior of the end cap.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a lathe to which an optical fiber preform tube is rotatably mounted for chemical vapor deposition.
FIG. 2 is a side elevational view, in cross-section, of the sealed junction or joint of the rotatable and stationary members of the apparatus illustrated in FIG. 1 which joint is also referred to herein as a rotary seal.
DETAILED DESCRIPTION
Referring now in more detail to the drawing, there is shown in FIG. 1 a lathe for forming an optical fiber preform by a vapor deposition process wherein chemical reaction products are deposited on the interior surface of a glass preform tube 10. The lathe includes a frame 11 atop which a headstock 12 and a tailstock 13 are mounted. The headstock 12 and its internal mechanisms rotatably support and drive a chuck 15 while the tailstock 13 and its internal mechanisms similarly rotatably support and drive chuck 16 about a common axis with that of chuck 15. Each of the chucks is comprised of radially spaced jaws 18 which are adpated to be moved into and out of gripping engagement with the preform tube or with a tubular extension thereof. Centrally apertured heat shields 20 are mounted by pendants 21 to both stocks closely adjacent the rotatable chucks. A hydrogen-oxygen torch 23 is mounted atop a carriage 24 for reciprocal movement between the two heat shields 20 as indicated by arrows 25. The torch 23 is reciprocated by an unshown automated drive mechanism which can be manually over-ridden and positioned by a handwheel 26. Similarly, the lateral position of the headstock 12 may be adjusted by a handwheel 27 atop a rail 30 while the position of the tailstock may be manually adjusted over the rail by movement of handwheel 28. A rotary conduit 32 projects laterally from the headstock 12 to a rotary seal 33 and junction with a stationary conduit 34. The conduit 34 extends to an unshown vapor stream supply source. An exhaust hose 37 extends from the tailstock while a scrapper rod 48 extends into the tailstock for cleaning.
FIG. 2 provides a detailed illustration of the rotary seal or joint 33. The seal includes a tubular member 50 which is rigidly mounted to the rotatable conduit 32 by a compression fit about two O-rings 51 sandwiched between the tubular member and conduit. Here the conduit 32 is an extension of the preform tube 10. Alternatively, the seal 33 may be positioned within the headstock 12 with the end of the glass preform tube 10 itself mounted within the rotatable member 50.
The rotatable member 50 is seen to have a neck portion 53 whose outer surface is cylindrical and of reduced outsdie diameter. A tubular insert 52 is press-fitted into an end of the neck portion 53. This insert is formed with two axially spaced grooves in which a pair of resilient O-rings 54 are seated.
The rotary seal is seen further to include an end cap or housing 55 having a cylindrical internal wall 56 which defines a bore that is open-ended to ambient atmosphere at one end 57. The cylindrical bore has an inside diameter slightly greater than the outside diameter of the neck portion 53 of the rotatable tube 50. The end cap is provided with a passage 58 coaxially that of the cylindrical bore through which a conduit 34 extends into the rotatable tube neck portion 53 and through the two O-rings 54. The end cap has another passage 59 through which another conduit 60 extends from an unshown source of compressed oxygen.
During chemical vapor deposition the preform tube 10 is rotated by chucks 15 and 16. A stream of the aforementioned vapors, most of which are toxic, entrained with oxygen as a carrier gas, is formed into the preform tube 10 by positive pressure provided by an unshown vapor stream generator located upstream of conduit 34. As the vapor stream is passed through the preform tube the torch 23 is slowly moved along the rotating preform tube thereby causing a chemical reaction to occur within the band of heat created by the torch, and the products of the reaction to be deposited on the interior surface of the tube. The carrier gas, along with any undeposited reaction products, is exhausted out of the preform tube 10 through the exhaust tube 37 to which suction is applied.
As the deposition process progresses the rotatable tube 32 and its tubular extension 50 are rotated by the chuck 15 as indicated by arrow 62. As this occurs the tubular neck portion 53, the tubular insert 52 and the two O-rings 54 also rotate about the stationary conduit 34. Oxygen is introduced into the end cap bore through conduit 60 at a pressure in excess of ambient air pressure and that of the vapor stream flowing through the sealed joint. From here the oxygen flows through the annular channel located between the end cap interior wall 56 and the exterior cylindrical wall of the rotatable member neck portion 53 to ambient. The pressure of the oxygen within the end cap is also above the pressure of the vapor stream flowing through the conduit 34 and into conduit 32. As a result the toxic vapor stream is inhibited from leaking outwardly through the O-rings into the end cap bore and then to the ambient atmosphere due to this presssure differential. Conversely, the O-rings also serve to inhibit the oxygen from flowing inwardly into the rotatable member 50 and the vapor stream. However, should any of the oxygen seep past the O-rings and into the vapor stream the qualitative compositional makeup of the vapor stream is unaltered. In such cases there would be a slight increase in the percentage of oxygen as the carrier gas to the toxic vapor entrained therewith. However, with the flow rate of the vapor stream being substantially greater than the flow rate of the purging oxygen being inputted through conduit 60, the change in the ratio of carrier gas to vapor is very slight. In this manner the composition of the vapor stream is prevented from being contaminated by ambient air and the moisture which it contains. Since oxygen is a constituent of the vapor stream the qualitative composition of the stream is maintained. At the same time there is little if any risk of toxins escaping from the vapor stream and thereby endangering personnel or damaging property located in the vicinity of the rotary seal.
It should be understood that the just described embodiment merely illustrates principles of the invention in a preferred form. The words "stationary" and "rotary" are used herein are intended to be mutually relative terms. Furthermore, for ease of expression air has been used as the ambient fluid medium in which the rotary seal is located. In other circumstances, of course, the ambient atmosphere could be other than that of air such as an inert gas. In addition the various fluids described have been gaseous; however, liquid fluids could be used in other applications. Thus, it is apparent that many additions, deletions and modifications may be made to the methods and apparatuses particularly described without departure from the spirit and scope of the invention as set forth in the following claims.
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Apparatus for supplying fluid to a rotary tube uncontaminated with ambient air comprises an end cap having an open ended bore in which an end portion of the tube may be rotatably positioned, a first conduit extending into the end cap through which fluid may be fed into the rotary tube, and a second conduit communicating with the end cap bore through which a purge fluid may be fed into and at least partially through the bore to the exterior of the end cap.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 60/318,823 filed Sep. 14, 2001, incorporated by reference herein.
FIELD OF THE INVENTION
This invention relates to an incinerator, and more particularly to an incinerator which provides safe operation and efficient disposal of hazardous, explosive or illicit materials and which can withstand internal shocks.
BACKGROUND OF THE INVENTION
Disposal of hazardous, explosive or illicit materials requires a unit which can be displaced in order to burn the material at a site or near a site where the material is stacked. This alleviates hazards and costs related to transporting the material off site.
In the past, it was common to dig a pit, place the contraband in the pit, pour accelerant over the material and burn it. This method has been deemed totally unacceptable as it generates unrestrained noise and pollution from known pollutants, such as lead, antimony, potassium nitrate, sodium nitrate and sulfur. There is also a threat of various unknown pollutants due to the diversity of material that can be processed, including various heavy metals and organic chemicals, such as nitrocellulose, nitroglycerine and DBP (plasticizer).
Another known method of burning ammunition makes use of an open drum that contains two trays with fissures. In the bottom tray, fuel in the form of fuel oil and wood shavings are added, and the ammunition is added to the top tray. During the burning process, part of the low boiling metals are melted and fall through the tray fissures and into the drum bottom. Due to the explosive nature of the material, pollutants are emitted into the air and eventually fall to the ground.
An ammunition incinerator, known as the “Hurd” burner from the Hurd's Custom Machinery Inc. has a reinforced body, defining a single combustion chamber, in the shape of a fuel tank. The burner fires directly in the combustion chamber and there is no reburn system. This unit generates a lot of smoke, which contains noxious gases from the ammunition. Also the manual ignition of this device leaves too much room for error, causing structural damage at the door and being hazardous for the operator.
U.S. Pat. No. 5,727,481, issued on Mar. 17, 1998 discloses a mobile armored incinerator for similar uses, which provides pressure release hatches and a reburn system, but the latter is not integrally built in the body. The burners fire directly in the primary chamber and there are air intakes in direct communication with the primary chamber. This leaves many exposed parts which may be hit by projectiles, or gaps from which projectiles can escape. Also, the loading cart does not provide material separation.
In general, incinerators are designed to be used with regular refuse material. Typically, their internal walls are made of refractory material, and they do not include armored panels nor overpressure hatches to cushion possible sudden blows.
Therefore there is a need for an incinerator which alleviates some of the disadvantages of the prior art.
SUMMARY OF THE INVENTION
This invention relates to an incinerator capable of withstanding internal shocks resulting from the combustion of the material to be burned.
Thus, according to one aspect, the invention provides an incinerator capable of withstanding internal shocks resulting from combustion of material to be burned, the incinerator comprising a body including a primary combustion chamber for burning the material, a heating chamber for providing heat to the combustion chamber, and a bullet proof separation plate providing separation between the primary combustion chamber and the heating chamber to prevent projectiles from escaping, and providing sufficient heat exchange between the primary combustion chamber and the heating chamber.
There are many advantages in using an incinerator according to the invention. First, by containing projectiles emitted during the combustion process, and therefore various pollutants, that are propelled into the air, contact of the pollutants with the ground is eliminated, which in turn controls the environmental impact on soil, water and air. Also, by burning at high temperatures, combustion efficiency is improved and the levels of emitted pollutants to the air may be decreased.
Other aspects and advantages of embodiments of the invention will be readily apparent to those ordinarily skilled in the art upon a review of the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described in conjunction with the accompanying drawings, wherein:
FIG. 1 is a front perspective view of the incinerator in accordance with this invention with the door opened to show some interior elements;
FIG. 2 is a front view of the incinerator of FIG. 1 with the door removed to show constructional details;
FIG. 3 is a side view of the incinerator showing constructional details and a schematic of the gas circuit; and
FIG. 4 is a front view of the incinerator with the door closed.
This invention will now be described in detail with respect to certain specific representative embodiments thereof, the materials, apparatus and process steps being understood as examples that are intended to be illustrative only. In particular, the invention is not intended to be limited to the methods, materials, conditions, process parameters, apparatus and the like specifically recited herein.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, there is illustrated an armored incinerator 10 , having a generally cylindrical body 60 , closed at one end and open at the other end. The open end is adapted to be closed by a door 50 . The body 60 includes a primary combustion chamber 15 , and a heating chamber 20 having first heating means 105 .
The primary combustion chamber 15 includes a support means, preferably in the form of a loading tray 25 , where the material to be burned is fed. There are also air intakes 175 (seen in FIG. 2) to allow ambient air to pass into the primary combustion chamber via the heating chamber. A secondary combustion chamber 40 is located in an upper portion of the primary chamber 15 and has a second heating means 120 (seen in FIG. 3 ), and an exhaust vent 45 . A heating plate, or separation plate, 30 separates the primary combustion chamber 15 from the heating chamber 20 . The heating plate 30 serves to provide a heat exchanging means between the heating chamber 20 and the primary combustion chamber 15 , and to distribute the heat evenly from the heating chamber 20 in the primary combustion chamber 15 . Plate 30 also prevents projectiles, which result from the combustion, from escaping the primary combustion chamber 15 via the air intakes 175 .
The first heating means 105 is in the form of heating elements in communication with external primary gas burners 100 (seen in FIG. 3 ). The second heating means 120 is in the form of external gas burner in communication with the secondary combustion chamber 40 . Propane gas or natural gas can be used interchangeably, either from a gas tank 160 or directly from a source line. Electrical means can be used instead of gas burner without departing from the scope of the invention.
Referring to FIGS. 1 and 3, the body 60 of the incinerator unit comprises several panels 66 to 73 welded, or secured by expansion joints, to form a polygon in cross-section. It will be appreciated that the incinerator can be of various proportions and sizes to be adapted to different situations. In one embodiment, these panels form an octagon, however other shapes such as hexagon, heptagon or dodecagon can be used without departing from the invention. Two of these panels 66 , 70 are vertically disposed to form opposite sides of the body 60 . These panels are welded, or otherwise fastened, to the extensions 81 , 82 of the frame. The two upper corner panels 67 , 69 adjacent and disposed over the vertical panels 66 , 70 converge to either the next panel 68 (to form an octagon), to the next panels (to form a decagon, not shown), or to a common joint (to form a hexagon or heptagon, not shown).
The upper corner panels 67 , 69 each have a pressure control means to control the pressure in the primary combustion chamber 15 , comprising overpressure apertures 74 , 75 each covered by a hinged panel 64 , 65 . The hinged panels 64 , 65 have hinge means 61 , 62 on one side, and can sit by gravity over their respective upper corner panels 67 , 69 or have means to remove or add some weight to the hinged panel depending on the side and weight of the latter. This is dependent upon the pressure limit which is considered as unsafe operation. In this embodiment, the right hinged panel 64 is shown in a closed position, and the left hinged panel 65 is shown in an open position. Steel or other high impact material screen 76 , 77 covers the inside of the overpressure apertures 74 , 75 to prevent projectiles to escape the unit in the event that the overpressure panels 64 , 65 have to open in operation.
Tray supports 27 and plate supports 36 , each inside the vertical panels 66 , 70 removably retain respectively, the loading tray 25 and the heating plate 30 . These supports 27 , 36 can be an integral part of the vertical panels 66 , 70 , or can be a separate element welded, or otherwise fastened, to the vertical panels 66 , 70 . The loading tray 25 has perforations to permit the material in fusion or in sub-fluidic state to flow through or pass through these perforations and to fall on the heating plate 30 . The loading tray 25 also has lips 26 which cooperate with the tray supports 27 , to allow the loading tray to be removable. Generally, the loading tray 25 slides in and out of the unit, with the material to be burned disposed upon the loading tray 25 .
A second tray 28 (seen in FIG. 4) is also supported in the bottom part of the frame, by sliding over supports 29 (seen in FIG. 4 ). Tray 28 can be used for a second load of material to be processed. Generally, tray 28 is removed from the incinerator while the material in tray 25 is being combusted, so that resulting debris may fall from heating plate 30 . Also, when a burn has just finished, it is possible to use these supports 29 to let the tray 25 , coming from the primary combustion chamber 40 , cool down before any other manipulation.
The heating plate 30 is curved or sloped, from the front view, to force the material having passed through the loading tray 25 , usually the material having lower fusion temperature, to a central funnel portion 31 in the heating plate 30 . The heating plate 30 is also curved or sloped, perpendicularly from the front view, to force the same material to converge to this funnel portion 31 . The funnel portion 31 is in communication with a passage 32 adjacent to, and heated by, the first heating means 105 so that the material is in a flowable state. The material flows out of the body 60 , by an aperture 33 in the bottom plate 72 , to a collecting bin 34 under the unit. The bin 34 can be of various designs, from a single use bin to a mold to form ingots. The other part of the burned material (usually of higher fusion temperature and bigger dimension) remains on the loading tray 25 , which is removed after a burn to be cleaned for the next batch.
A box 41 insulates the primary combustion chamber 15 from the secondary combustion chamber 40 . This box 41 can be formed by a panel (for hexagonal or heptagonal units, not shown), or panels 42 (for octagonal or decagonal units), and the top panels of the body (for hexagonal or heptagonal units, not shown), or the top panel 68 of the body (for octagonal or decagonal units). The box 41 is closed at the front end by a panel 43 and opened at the back end to permit the flow of the gases exiting or emanating from the primary combustion chamber into the secondary combustion chamber 40 , where the exhaust gases are burned off at a higher temperature and for the passage of the secondary burning element 120 (seen in FIG. 3 ). Exhaust gas from the secondary combustion chamber 40 exits through an aperture in the top panel 68 (for octagonal or decagonal units) or at the intersection of the top panels (for hexagonal or heptagonal units), adjacent to the front end of the box, through the exhaust vent 45 , such as a catalytic converter or a simple chimney.
All the internal walls of the primary combustion chamber 15 can be covered by stainless steels sheets or with any other heat resistant material capable of withstanding high impact. These sheets may be applied inside the top part of the vertical panels 66 , 70 , of the upper corner panels 67 , 69 , the top panel 68 and the hinged panels 64 , 65 . In this way, the material of the panels 64 to 73 of the body 60 can resist penetration by most projectiles. The outside walls of the secondary combustion chamber 40 may be insulated on the inside in order to retain the heat during operation.
Referring to FIGS. 1 and 3, the first heating means 105 of the primary combustion chamber 15 are fed from the gas burners 100 (typically, one on each side). A local control manifold 150 regulates the flow of gas, from the information given by the user via a remote control unit 155 and from temperature sensors, such as thermocouples 125 , 130 , 135 . The local control manifold 150 incorporates the necessary control valves and regulators (not shown) disposed according rules and standards of gas installations as known in the art. From this circuitry, the gas burners 100 and the secondary gas burning element 120 are fed with gas using gas lines 101 , 121 respectively. Thermocouples 125 , 130 , 135 are disposed in some or all the chambers to detect undesirable temperature variations, these thermocouples are linked to the local control manifold 150 by heat resistant electrical cables 126 , 131 , 136 , respectively. Control means (not shown) in the local control manifold 150 regulates the flow of gas from signals received from the thermocouples 125 , 130 , 135 and from other sensors which can be also incorporated to detect other parameters, such as pressure, presence of specific gas, velocity of gases, etc.
With the local control manifold 150 and the remote control unit 155 , the operator can start/ignite or stop the incinerator from a safe distance. Also by having a simple means for ignition the operator can pay more attention to the surrounding of the unit to detect any sign of hazard.
The incinerator can be mounted on extensions 81 , 82 of a supporting frame 80 on each side of the body, to be supported by the leg parts 83 , 84 , and then be transported from site to site by hoisting the unit by the frame elements on each side of the body, for example frame elements 85 . Also, any part of the frame 81 to 87 can be secured, fastened or welded to a structure, such as a trailer, a sleigh, a barge, or even to a fixed structure, if needed. These installations will have to be done according to applicable safety standards and leaving enough room around the unit for heat dissipation.
Referring now to FIG. 4, the front end of the body 60 is closed during operation of the incinerator by a door 50 , which can also preferably, totally cover the top part of the frame. One solution to obtain a blast resistant door is to have reinforcement bars 51 over the door having extensions 53 on each side. These extensions 53 cooperate with similar extensions 52 (seen in FIG. 1) on each side 81 of the frame.
The door may include hinges on one side for improved strength. Also, an electric shut-off (not shown) may be included as a safety measure to shut off the propane in the event that the door opens.
Also, there may be included a fan and airduct (not shown) mounted to the incinerator and cooperating with the heating chamber. The fan may be remotely operated by remote control unit 97 to speed up the cooling process of the incinerator after the burning process. This will allow the next load of material to be loaded up and burned sooner.
Numerous modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
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An incinerator, capable of withstanding internal shocks from projectiles resulting from the combustion of energetic materials, is made of a primary combustion chamber where the material is burned, and a secondary chamber to reburn at a higher temperature the gases emanating from the primary chamber. The incinerator has a heating or separation plate, having a flowing-material funnel facilitating the removal of waste solids, to provide heat exchange between the primary combustion chamber and a heating chamber, to protect the heating elements against projectiles, and to restrain any projectiles from exiting the unit. To increase the level of safety of operation, this incinerator is remotely controlled, has a sequence of ignition and has overpressure apertures over the primary chamber.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional application of U.S. patent application Ser. No. 12/970,810 filed on Dec. 16, 2010, which claims priority to and the benefit of Korean Patent Application No. 10-2010-0025138 filed in the Korean Intellectual Property Office on Mar. 22, 2010, the entire contents of the prior applications being incorporated herein by reference.
BACKGROUND
1. Field of Disclosure
The present disclosure of invention relates to electrophoretic displays and methods of manufacturing the same. More particularly, the present disclosure relates to a method of binding together an electrophoretic film and an array substrate against which the electrophoretic film is flattened and aligned; with use of adhesive that is activated at high temperature.
2. Description of Related Art
Generally, an electrophoretic display apparatus operates as a reflective type of display that selectively reflects light incident thereon and which is received from an external source where the selectively reflected light appears as an informational image to a user (viewer) of the display. More particularly, the electrophoretic display apparatus is generally structured to include a plurality of small microcapsules each enclosing white ink particles pre-charged for example with a negative electric charge, black ink particles pre-charged with an opposed positive electric charge, and a dielectric fluid where the microcapsule is disposed between two electrodes, one of the electrodes often being a light-passing (e.g., transparent) electrode.
In the electrophoretic display apparatus, a voltage is applied and an electric field is formed as between the opposed electrodes of a respective one or more microcapsules. In response to a first voltage polarity and voltage magnitude, a white reflecting surface is caused to be displayed when the white ink particles assemble adjacent to a viewing side of the light-passing microcapsule. By contrast and in response to an opposed second voltage polarity and sufficiently strong second voltage magnitude, a black color reflecting surface is caused to be displayed when the black ink particles exchange positions with the white particles and come to be instead assembled adjacent to a viewing side of the microcapsule. Thus when a white light is incident from an external source onto differently driven microcapsules, the electrophoretic display apparatus displays an image (e.g., black and white; or absorbing versus reflecting) corresponding to the white-light reflecting or black and thus light-absorbing pixels defined by the respectively differently driven ones of the microcapsules.
One type of electrophoretic display apparatus is manufactured by binding an electrophoretic microcapsules containing film to an array substrate on which a driving circuit integrally is formed. It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.
SUMMARY
A method of manufacturing an electrophoretic display in accordance with the present disclosure includes: forming a monolithically integrated array substrate including a plurality of thin film transistors (TFTs) with each being electrically connected to a corresponding gate line, a corresponding source line (data line), and a corresponding pixel electrode; overlapping, flattening and aligning a flexible electrophoretic film having an electrophoretic layer against the array substrate where the adhesive is interposed between the electrophoretic film and the array substrate; and annealing (curing) the adhesive at a temperature of more than about 60° C. but less than an adhesive decomposing one (e.g., about 150° C.) for thereby providing a substantial increase of adhesive strength to the adhesive after the patterned electrophoretic film has been aligned to and flattened against the array substrate.
The adhesive may include at least two reactive compositions whose cross reaction is selectively induced by a temperature substantially above room temperature, and the at least two compositions may include a phenol resin.
The at least two compositions may include an acrylic rubber.
The adhesive may include a silicon filler at over 0% and under 15% by weight composition ratio.
The adhesive may include an acrylic rubber at over 40% and under 80% by weight composition ratio.
The adhesive may include a phenol resin such as bisphenol A and an epoxy resin.
The adhesive may include an epoxy phenol resin at over 0% and under 50% by weight composition ratio, a silicon filler at over 0% and under 15% by weight composition ratio, and an acrylic rubber at over 40% and under 80% by weight composition ratio.
An electrophoretic display in accordance with the present disclosure includes: an array panel including a thin film transistor connected to a gate wire and a source wire, and a pixel electrode connected to the thin film transistor; an electrophoretic film including a patterned electrophoretic layer (e.g., one having a framing area that frames (surrounds) a display area thereof) and a common electrode; and an adhesive positioned between the electrophoretic film and the array panel, wherein the adhesive includes a phenolyic resin such as bisphenol A and an epoxy resin.
The adhesive may include an epoxy phenol resin made of an epoxy resin and a phenol and having an over 0% and under 50% weight composition ratio.
The adhesive may include a silicon filler at 0% and under 15% by weight composition ratio.
The adhesive may include an acrylic rubber at over 40% and under 80% by weight composition ratio. The manufactured electrophoretic display in accordance with the present disclosure has the patterned electrophoretic layer that may be pre-aligned to and flattened against a corresponding pattern (e.g., display area and peripheral area) on the array substrate, with the pre-aligned and flattened electrophoretic layer being strongly adhered to the array panel by a temperature cured version of the adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages of the present disclosure of invention will become more apparent by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which:
FIG. 1 is a plan view illustrating an electrophoretic display apparatus according to an example embodiment;
FIG. 2 is a cross-sectional view illustrating the electrophoretic display apparatus according to a first example embodiment taken along a line I-I′ of FIG. 1 ;
FIGS. 3A and 3B are sectional views illustrating a method for manufacturing the electrophoretic display apparatus in FIG. 2 ;
FIG. 4A is a chemical formula of an exemplary adhesive composition of a bisphenol A type;
FIG. 4B is a chemical formula of an exemplary adhesive composition epoxy resin;
FIG. 5 shows SEM and AFM pictures according to exemplary X1 and X2 samples; and
FIG. 6 is a diagram of weight variation according to an increase of temperature for exemplary X1, X2, and X3 samples.
DETAILED DESCRIPTION
The present teachings are described more fully hereinafter with reference to the accompanying drawings in which embodiments in accordance with the disclosure are shown. These teachings may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present teachings to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.
It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” or “directly coupled” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present disclosure.
Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are to be interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure of invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from details of manufacturing. For example, an implanted region illustrated as a rectangle will typically have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from an implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation takes place. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the present teachings.
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 disclosure most closely pertains. 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.
Hereinafter, embodiments will be explained in detail with reference to the accompanying drawings.
FIG. 1 is a plan view illustrating an electrophoretic display apparatus formed according to an example first embodiment of the present teachings.
Referring to FIG. 1 , the electrophoretic display apparatus includes an electrophoretic display panel 300 and an electrical driving part 410 structured and connected for driving the electrophoretic display panel 300 .
The electrophoretic display panel 300 includes an array substrate 100 and an electrophoretic film 200 , flattened against and adhesively bonded to the array substrate 100 . The array substrate 100 is patterned to include a display area DA of predefined size and shape (e.g., rectangular) and a peripheral area immediately surrounding the display area DA.
Individual pixel portions P are defined in the display area DA as areas bounded by source lines DL and gate lines GL, where the latter two are nonconnectively crossing each other. Each of the pixel portions P includes a thin film transistor TFT (only one shown) electrically connected to the gate and source lines, GL and DL, corresponding to each pixel portion P. Each of the pixel portions P may be further schematically represented as having a corresponding electrophoretic capacitor EPC electrically connected to the TFT, and a storage capacitor CST electrically connected, for example in parallel with the EPC.
The peripheral area includes a peripheral first outer area OA (also referred to here as a picture framing area) disposed immediately adjacent to the display area DA and surrounding the display area DA like a picture frame, a first further peripheral area PA 1 that corresponds to a portion where the source lines DL extending outside of the display area DA and where the driving part 410 is disposed to connect with them. The peripheral area also includes a second further peripheral area PA 2 corresponding to a portion where the gate lines GL extend outside of the display area DA. The second further peripheral area PA 2 includes a circuit area CA in which a gates-driving circuit part GIC is formed for outputting corresponding gate signals to the gate lines GL. The gates-driving circuit part GIC is monolithically integrated with the display area DA elements (e.g., TFTs) to the substrate 300 . As is the case with the display area DA, the gates-driving circuit part GIC has a predefined shape and size and location relative to the display area DA, and in one embodiment, a correspondingly patterned portion of the electrophoretic film 200 might desirably need to be aligned with the circuit area CA.
More specifically, a light blocking electrode (not separately shown in FIG. 1 ) is formed in the peripheral area portion OA of the array substrate 100 , and a patterned light blocking layer covering the gate circuit part GIC is further formed in the circuit area portion CA of the array substrate 100 . As a consequence, the electrophoretic film 200 has to be properly aligned to the correspondingly patterned portions of the underlying array substrate 100 so as to provide electrically activated light-blocking action as will be described below.
More specifically, during operation, a data voltage corresponding to a black grayscale is applied to the light-blocking electrode of the electrophoretic film 200 , for thereby causing the portion of the electrophoretic layer located there to display the black grayscale in that area. Accordingly as the peripheral area OA (a.k.a. framing area) immediately adjacent to the display area DA is displayed in the contrasting black grayscale, viewing ability of an image displayed in the display area DA is relatively enhanced. The light-blocking layer of the electrophoretic film 200 blocks external light from being incident to active electronic elements of the underlying gate circuit part GIC formed in the circuit area CA, to thus prevent the gate circuit part GIC from being erroneously operated.
The electrophoretic film 200 includes, at its user-viewed major surface, an integral common electrode formed of a light-passing (e.g., transparent) and electrically conductive material. The transparent common electrode is formed on a supporting base substrate made of a flexible material. The electrophoretic film 200 further includes an electrophoretic layer is formed on the common electrode. The electrophoretic layer includes electrophoretic molecules or particles (e.g., microcapsule encapsulated particles) charged with either a positive (+) charge and a negative (−) charge. The electrophoretic film 200 is adhesively attached to a top major surface of the display area DA portion of the main array substrate 100 , as well as to the second peripheral area PA 2 , and the peripheral area OA of the array substrate 100 .
FIG. 2 is a cross-sectional view taken along a line I-I′ of FIG. 1 and illustrating the electrophoretic display apparatus according to a first example embodiment.
Referring to FIGS. 1 and 2 , the electrophoretic display apparatus includes the array substrate 100 and the electrophoretic film 200 pre-aligned to, flattened against, and thereafter strongly adhesively bonded to the array substrate 100 . The array substrate 100 includes a first base substrate 101 , and the first base substrate 101 has the display area DA, the peripheral area OA, and the circuit area CA defined on an upper major surface thereof.
A thin film transistor layer TL is formed in the display area DA. The thin film transistor layer TL includes a plurality of thin film transistors (TFTs) each having a respective gate electrode GE, a portion of gate insulating layer 120 , a channel portion CH, a respective source electrode SE, a respective drain electrode DE, a portion of protective insulating layer 150 , a portion of first organic insulating layer 160 , and a respective pixel electrode PE.
The gate electrode GE of each TFT is formed to be extended from a corresponding gate line GL, and the gate insulating layer 120 is formed on the gate line GL and on the gate electrode GE. The channel portion CH includes an active layer 131 including an amorphous silicon (a-Si) and a low-resistance contact layer 132 including amorphous silicon (a-Si) doped with N-type dopants at a high concentration (n+ a-Si).
The source and drain electrodes SE and DE are formed on the channel portion CH, but separated from each other by a TFT channel area. When the TFT is turned ON, the source and drain electrodes, SE and DE. of the TFT are effectively electrically connected with each other through a made-conductive portion of the channel portion CH. The source electrode DE is formed to be extended from the source line DL, and the drain electrode DE is electrically connected to the pixel electrode PE through a contact hole CT. Thus, the thin film transistor TFT having the gate electrode GE, the channel portion CH, the source electrode SE and the drain electrode DE is formed.
The protective insulating layer 150 and the first organic insulating layer 160 are formed one after the next in the recited order on top of the first base substrate 101 and on top of the thin film transistors TFTs formed on the first base substrate 101 . The protective insulating layer 150 and the first organic insulating layer 160 have the contact hole CT defined through them so that a portion of the drain electrode DE is exposed for connecting with the pixel-electrode PE. In one embodiment, the first organic insulating layer 160 is composed of a transparent organic insulating material. The upper surface of the first organic insulating layer 160 ; as well as the upper surface of a soon-described, second organic insulating layer 180 has a composition that can strongly bind with a thermally activated adhesive layer 500 provided between the bottom major surface of the electrophoretic film 200 and the top major surface of the array substrate 100 , where the latter top surface of substrate 100 is defined by coplanar upper surfaces of the first and second organic insulating layers, 160 and 180 . The thermally activated adhesive layer 500 also binds well to the conductive material of electrodes 191 and 192 in the areas where those black-grayscale inducing electrodes are formed.
The pixel electrode PE is formed on the first organic insulating layer 160 , to be electrically connected to the drain electrode DE through the contact hole CT.
The gate insulating layer 120 , the protective insulating layer 150 , and the first organic insulating layer 160 are sequentially formed on the peripheral area OA (a.k.a. framing area) as well. A light-blocking (and black-grayscale inducing) electrode 191 made for example of an opaque metal material is formed in the array substrate 100 to be disposed directly above the first organic insulating layer 160 . During operation, a black grayscale voltage is applied through an appropriate connector to the blocking electrode 191 to cause display thereat of the black grayscale as mentioned above.
The circuit area CA includes a gate circuit layer GCL electrically connected to the plurality of thin film transistors of the display area DA, a second organic insulating layer 180 , and a light-blocking layer 192 .
The gate circuit layer GCL includes a gate metal layer 110 , the gate insulating layer 120 , the channel layer 130 , a source metal layer 140 , the protective insulating layer 150 , and a contact electrode 172 . In one embodiment, the gate circuit layer GCL and the thin film transistor layer TL are simultaneously formed via the same manufacturing process. The second organic insulating layer 180 may be composed of the same transparent organic insulating material as used for the first organic insulating layer 160 .
The blocking layer 192 in the CA area of the array substrate 100 may be composed of the same opaque metal material as used for the blocking electrode 191 in the OA area (a.k.a. framing area). The blocking layer 192 is formed to alignably cover the gate circuit layer GCL, to thus prevent light from being incident to the gate circuit layer GCL from an external source. Thus, leakage current is prevented from flowing due to light striking light-sensitive active elements in the gate circuit part GIC. The second organic insulating layer 180 electrically insulates the contact electrode 172 (which contact electrode 172 can extend to outside the second organic insulating layer 180 ) and the blocking layer 192 . The second organic insulating layer 180 helps to flatten (planarize) the upper surface of the array substrate 100 just as does the coplanar top of the first organic insulating layer 160 formed in the peripheral area OA help to flatten (planarize) the upper surface of the array substrate 100 .
The electrophoretic film 200 includes a second base substrate 201 , a common electrode 210 , and an electrophoretic microcapsules-containing layer 240 .
The second base substrate 201 may be made of a flexible material. For example, the second base substrate 201 may include a polyethylene terephthalate (PET) having good light transmissivity, good heat-resistance, good resistance to chemical attack, good mechanical strength, and so on.
The common electrode 210 includes a transparent conductive material. The common electrode 210 is disposed opposite to pixel electrodes PE of the array substrate 100 so as to thereby sandwich the microcapsules in between. A common voltage is applied to the common electrode 210 . The common electrode is composed of a transparent conductive material, such as indium tin oxide (ITO), indium zinc oxide (IZO), amorphous indium tin oxide (a-ITO), and so on. The pixel-electrodes PE need not be light-passing ones (since the display operates by reflection of incident light) but they nonetheless can be such and can be also composed of a transparent conductive material, such as indium tin oxide (ITO), indium zinc oxide (IZO), amorphous indium tin oxide (a-ITO), and so on. Alternatively, the pixel-electrodes PE may be composed of an opaque and otherwise appropriate conductor.
The electrophoretic layer 240 includes a plurality of microcapsules 230 and a flexible transparent binder (not referenced with a number) binding the plurality of microcapsules 230 together. Each of the microcapsules 230 includes the electrophoretic molecules or particles charged with one or the other of the positive (+) and negative (−) charges.
Particularly, in one embodiment, the microcapsules 230 include white ink particles 231 charged with the negative (−) charge and the positive (+) charge, black ink particles 232 charged with the opposite charge to the white ink particles 231 , and a transparent dielectric 233 . Alternatively the white ink particles 231 may be charged with the positive (+) charge and the black ink particles 232 may be charged with the negative (−) charge. As shown in FIG. 2 , if the white ink particles 231 are positioned at the upper side, the light incident from the external source is reflected by the white ink particles 231 to thus display a corresponding white colored or white light-reflecting area. (User-observed color may vary if color filters of different colors, e.g., R, G, B are provided above the electrophoretic film 200 .)
FIGS. 3A and 3B are sectional views illustrating a method for manufacturing the electrophoretic display apparatus of FIG. 2 .
Referring to FIGS. 2 and 3A , the thin film transistor layer TL is integrally formed on the first base substrate 101 in the display area DA, and the gate circuit layer GCL is integrally formed in the circuit area CA.
Particularly, a first metal layer is deposited and patterned on the first base substrate 101 . Then, the gate electrode GE and the gate line GL are formed in the display area DA, and the gate metal layer 110 is formed in the circuit area CA. The patterned gate metal layer 110 includes the gate electrodes of the plurality of thin film transistors forming the gate circuit part GIC.
The gate insulating layer 120 is formed on the first base substrate 101 on which the gate pattern is formed. The gate insulating layer 120 is formed in the display area DA, the peripheral area OA, and the circuit area CA in common.
The active layer 131 having amorphous silicon (a-Si) and the low-resistance contact layer 132 having amorphous silicon doped with N-type dopants at a high concentration (n+ a-Si) are sequentially deposited and patterned on the gate insulating layer 120 . Then, the channel portion CH is formed in the display area DA, and the channel layer 130 is formed in the circuit area CA. The active layer 131 and the low-resistance contact layer 132 are not formed in the peripheral area OA.
A second metal layer is deposited and patterned on the first base substrate 101 on which the channel portion CH and the channel layer 130 have been formed. Then, the source line DL, the source electrode SE, and the drain electrode DE are formed in the display area DA, and the source metal layer 140 is formed in the circuit area CA. The source metal layer 140 includes the source and drain electrodes of the plurality of thin film transistors forming the gate circuit part GIC.
The protective insulating layer 150 is formed on the first base substrate 101 on which the source pattern is formed. The protective insulating layer 150 is formed in the display area DA, the peripheral area OA, and the circuit area CA in common.
Then, the first organic insulating layer 160 having the transparent organic insulating material is formed in the display area DA and the peripheral area OA. However, the first organic insulating layer 160 is not formed in the circuit area CA. The transparency of the first organic insulating layer 160 may be used during manufacture to optically align patterned features below the first organic insulating layer 160 to patterned features of the electrophoretic film 200.
The first organic insulating layer 160 and the protective insulating layer 150 formed in the display area DA are patterned to form the contact hole CT. The protective insulating layer 150 and the gate insulating layer 120 formed in the circuit area CA are patterned to form a plurality of contact holes (not shown).
A conductive and optionally transparent electrode material is deposited and patterned on the first base substrate 101 on which the contact holes are formed, to thus form the pixel electrodes PE in the display area and to thus form a predefined pattern of contact electrodes 172 in the circuit area CA (which area is not yet covered by the second organic insulating layer 180 ). The contact electrodes 172 may extend beyond an area to be next covered by the second organic insulating layer 180 .
Accordingly, the thin film transistor layer TL is formed in the display area DA and the gate circuit layer GCL is formed in the circuit area CA. The gate insulating layer 120 , the protective insulating layer 150 , and the first organic insulating layer 160 are sequentially formed in the peripheral area OA.
Referring to FIGS. 2 and 3B , the second organic insulating layer 180 having the transparent organic insulating material is formed on the first base substrate 101 in the circuit area CA. The second organic insulating layer 180 is formed to cover the contact electrodes 172 . The first and second organic insulating layers, 160 and 180 are then planarized together so that the second organic insulating layer 180 planarizes its portion of the top surface of the array substrate 100 just as does the first organic insulating layer 160 planarize its respective portion of the top surface of the array substrate 100 .
An opaque metal material is next deposited and patterned on the second organic insulating layer 180 , to form the light-blocking electrode 191 in the peripheral area OA and to form the light-blocking layer 192 in the circuit area CA. Black grayscale data is applied to the blocking electrode 191 during operation so that the viewing ability of the image displayed in the display area DA is enhanced. The blocking layer 192 is formed to cover the gate circuit layer GCL to block the light from being incident to the gate circuit layer GCL.
The blocking electrode 191 and the blocking layer 192 are formed to complete the array substrate 100 . The electrophoretic film 200 having the electrophoretic layer 240 is laminated, and more specifically, flattened against and thereafter adhesively attached to the array substrate 100 by a below described bonding process. The electrophoretic film 200 is attached to cover the display area DA, the peripheral area OA, and the circuit area CA of the array substrate 100 .
A selectively activatable adhesive 500 is used when the electrophoretic film 200 is laminated (adhesively attached) to the array substrate 100 . In one embodiment, an adhesive film having a thickness of about 25 um is initially covered by protective films on both the front and rear surfaces thereof. First, the front cover is removed and the partly exposed adhesive film is laminated onto (e.g., flattened against so as to remove gas pockets and loosely held by electrostatic and/or alike weak adhesion forces to) the electrophoretic film 200 , and secondly, the rear cover is removed and the so-exposed electrophoretic film 200 is laminated onto (e.g., flattened against so as to remove gas pockets and loosely held by electrostatic and/or alike weak adhesion forces to) the array substrate 100 . At the time of the second laminating, precise arrangement (alignment) between the electrophoretic film 200 and the array substrate 100 may be required since the adhesive 500 , after it is thermally activated, will be strong enough to damage the surface of substrate if it is unintentionally contacted thereto in wrong alignment and afterwards, detachment is attempted. The damage to the electrophoretic film 200 or the array substrate 100 due improperly aligned strong attachment is expensive since it is a half-finished product and must be discarded if the bonding process is carried out with an acceptable flattening and/or alignment.
As taught by the exemplary embodiment of the present disclosure, the trouble may be solved by using a selectively activatable adhesive 500 that is selectively activated for example only at a temperature substantially higher than room temperature. Detaching at room temperature is easy and free from damage to the surface of the substrate since it is not particularly adhesive at room temperature or below. Accordingly, after the temperature-based hardening process is applied, the electrophoretic film 200 and the array substrate 100 are strongly adhered to each other by the cured adhesive layer 500 . That is, the electrophoretic film 200 and the array substrate 100 are first flattened out against each other and appropriately aligned with each other at room temperature or a lower temperature, and they are fixed in position relative to one another and thereafter permanently adhered to one another by hardening the adhesive 500 at a high temperature such that they are attached without any substantial misalignment or air or other gas pockets interposed therebetween. Also, although both surfaces are loosely attached via the not-yet-cured adhesive when trying to align at room temperature, detaching is easy prior to hardening such that damage due to detachment and re-lamination may not be generated even if a misalignment and/or wrinkle-air pocket is generated during a first lamination attempt.
Exemplary components of the adhesive composition 500 may include one or more phenolyic resins with an OH functional group and an epoxy resin having an aromatic (e.g., benzene-based) component. One example of the phenolyic resins may be bisphenol A, and the corresponding compound may be represented by the chemical formula of FIG. 4A . The structure of the epoxy resin is may be represented by the chemical formula of FIG. 4B . At the above room temperature range of about 50° C.˜150° C., the OH functional group of the phenolyic resin ( FIG. 4A ) is believed to chemically combine (e.g., cross polymerize with) with the epoxy resin to thus form a web-shaped epoxy phenol resin. Additionally, the acrylic groups of the acrylic rubber addend may attach at the sites indicated in FIGS. 4A-4B .
Thus, according to an exemplary embodiment, an adhesive is composed of at least three components of an epoxy phenolyic resin complex of which the phenolyic resin and the epoxy resin are combined (cross polymerized) by thermal reaction at an activating temperature, where the adhesive may additionally include at least one of an acrylic rubber and a silicon filler. Here, when included, the acrylic rubber preferably has a relatively low elasticity and thus contributes to relaxation of stress. Similarly, when included, the silicon filler is believed to contribute to improving cohesion within the adhesive film.
With an increase in proportion of epoxy content, the heat resistance (e.g., resistance to premature polymerization at lower temperatures) of the resulting adhesive material increases but its adhesion strength decreases and the amount of outgas increases. On the other hand, with an increase in proportion of the acryl contents, its heat resistance decreases. Since the silicon filler is agglomerated when the content of the silicon filler is increased, it is desirable to be controlled to be under about 10 wt % with a 1 micron average particle size (e.g., average diameter).
The statistically processed results of testing are shown in Table 1 with respect to properties regarding transmission, detaching, and outgassing. In the experiments, a testing film is inserted between two pieces of glass, light-transmission is measured after it is hardened at 150° C. with a light of a 440 nm wavelength, a T-peeling test is performed to estimate detachment for a rework, the angle between the detaching film and the attached part is kept at 90° and the weight change with the increase of temperature is measured to estimate the amount of outgas.
Formulation X1 in the given Table 1 is composed of 30 wt % of epoxy phenol resin, 60 wt % of acrylic rubber, and 10 wt % of silicon filler, and the average particle size of the epoxy hardener is 500 nm. Formulation X2 is composed of 10 wt % of epoxy phenol resin, 80 wt % of acrylic rubber, and 10 wt % of silicon filler, and the average particle size of the epoxy hardener is 100 nm. The third formulation, X3 is composed of 20 wt % of epoxy phenol resin, 70 wt % of acrylic rubber, and 10 wt % of silicon filler, and the average particle size of the epoxy hardener is about 10 nm.
TABLE 1
HS-300-
HS-300-
HS-300-
Items
10-X1
10-X2
10-X3
Trans-
Transmittance at 400 nm
22
45
82
parency
(%)
(Foaming)
Work-
Tackiness at 40° C.(N)
0.11
2.3
0.35
ability
Hand peeled
GOOD
BAD
PASS
T-peel
PE cover
0.6
27
0.7
strength
film
(N/m)
PET base
1.7
2.2
0.3
film
Outgas
Temperature
−1%
292
141
243
of mass
−3%
328
234
316
change
−5%
339
276
336
ratio (° C.)
In regards to properties of the outgas, a 1% weight loss in X1 and X3 was observed at a higher temperatures as compared to the −1% loss temperature of X2. In the same way, 3% and 5% weight losses of X1 and X3 were observed at higher temperatures as compared to the corresponding −3% and −5% loss temperatures of X2. In other words, thermal stability of X1 and X3 is better than that of X2 with regard to mass loss (e.g., due to outgassing).
In regards to detachment of a film at room temperature, X1 and X3 are relatively better than X2. From the test, required force to detach is minimal, at 0.3N/m in the combination of X3 and the PET base film.
The best performance in the light-transmission test was observed with X3.
In FIG. 5 , surface SEM (scanning electron microscope) and AFM (atomic force microscope) images in regards to X1 samples (left column) and X3 samples (right column) are presented. Phase decomposition of acryl rubber and epoxy resin is well established in the X1 sample as seen in its AFM image.
In FIG. 6 , weight change versus progressive increase of temperature in regards to X1, X2, and X3 samples is graphed. The superior thermal stability of the X1 composition (dashes only plot line) is shown as best in the diagram relative to X2 (dash-dot plot line) and X3 (solid) by virtue of the substantially more flat and low loss percent all the way out to about 300° C. whereas X2 and X3 exhibit faster mass loss at lower temperatures (although X3 is superior below about 250° C.).
Accordingly, if prevention of compositional change in the utilized adhesive is desired up to as high as about 300° C. (see FIG. 6 , X1 plot) and the higher surface roughness (see FIG. 5 , left column side) of cured X1 is acceptable, then the X1 composition and its approximating equivalents may be preferred. On the other hand, if a reduced surface roughness (see FIG. 5 , right column side) in the utilized adhesive is desired and a lesser selectivity in terms of activating temperature is acceptable, then the X3 composition and its approximating equivalents may be preferred.
The claims in this application are different from those of the application(s) from which priority is claimed. Applicant rescinds any disclaimer of claim scope made in the related application(s) and requests that any previous disclaimer and previously cited references be revisited. Further, any disclaimer made in the instant application is not intended to be read into the predecessor application(s).
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A method of manufacturing is disclosed for an electrophoretic display apparatus that includes an array substrate and an electrophoretic film laminated to the array substrate. A thermally activated adhesive is used to adhesively attach the electrophoretic film to the array substrate. The electrophoretic film is first aligned to and flattened against the array substrate and then a substantially stronger than original adhesion property of the adhesive is activated by annealing at a high temperature that is substantially greater than room temperature. Rework prior to annealing is therefore possible when alignment errors occur between the electrophoretic film and the array substrate.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 10/918,984, filed Aug. 16, 2004 by Sturm et al., entitled “MULTIPLE RF RETURN PAD CONTACT DETECTION SYSTEM”, now U.S. Pat. No. 7,160,293, which is a continuation of U.S. application Ser. No. 10/254,956, filed Sep. 25, 2002 by Sturm et al., entitled “MULTIPLE RF RETURN PAD CONTACT DETECTION SYSTEM”, now U.S. Pat. No. 6,860,881.
BACKGROUND
1. Technical Field
The present disclosure is directed to electrosurgery and, in particular, to circuitry for measuring or sensing the contact resistance or impedance between the patient and pairs of RF return pad contacts or electrodes employed in such surgery.
2. Description of the Related Art
One potential risk involved in electrosurgery is the possibility of stray electrical currents causing excess heating proximate the RF return pad contacts or patient return electrodes. The most common conditions which are thought to lead to excess heating include:
(1) Tenting: Lifting of the return electrode from the patient due to patient movement or improper application. This situation may lead to excess heating if the area of electrode-patient contact is significantly reduced;
(2) Incorrect Application Site: Application of a return electrode over a highly resistive body location (e.g., excessive adipose tissue, scar tissue, erythema or lesions, excessive hair) will lead to a greater, more rapid temperature increase. Or, if the electrode is not applied to the patient (i.e. electrode hangs freely or is attached to another surface), the current may seek an alternate return path such as the table or monitoring electrodes; and
(3) Gel drying either due to premature opening of the electrode pouch or use of an electrode which has exceeded the recommended shelf life.
Many monitor or detection systems have been developed in the past, but most cannot directly guard against all three of the above listed situations. In order to protect against these potentially hazardous situations, the contact resistance or impedance between the return electrode and the patient should be monitored in addition to the continuity of the patient return circuit.
Safety circuitry is known whereby split (or double) patient electrodes are employed and a DC current (see German Pat. No. 1,139,927, published Nov. 22, 1962) or an AC current (see U.S. Pat. Nos. 3,933,157 and 4,200,104) is passed between the split electrodes to sense the contact resistance or impedance between the patient and the electrodes. U.S. Pat. No. 3,913,583 discloses circuitry for reducing the current passing through the patient depending upon the area of contact of the patient with a solid, patient plate. A saturable reactor is included in the output circuit, the impedance of which varies depending upon the sensed impedance of the contact area.
The above systems are subject to at least one or more of the following shortcomings: (a) lack of sensitivity or adaptiveness to different physiological characteristics of patients and (b) susceptibility to electrosurgical current interference when monitoring is continued during electrosurgical activation.
U.S. Pat. Nos. 4,416,276 and 4,416,277 describe a split-patient return electrode monitoring system which is adaptive to different physiological characteristics of patients, and a return electrode monitoring system which has little, if any, susceptibility to electrosurgical current interference when monitoring is continued during electrosurgical activation. The entire contents of both U.S. Pat. Nos. 4,416,276 and 4,416,277 are incorporated herein by reference.
Still a need exists for a detection or monitoring system, which is: 1) adaptive to different physiological characteristics of patients; 2) has little, if any, susceptibility to electrosurgical current interference, (including interference or measurement interaction between components of the detection system); 3) can measure or sense the contact resistance or impedance between the patient and pairs of RF return pads or electrodes where multiple pairs of RF return pads are utilized due to the high current frequently needed during electrosurgery, such as during tissue ablation; and 4) eliminates or minimizes the risk of measurement interaction between the RF return pad pairs.
Therefore, it is an aspect of the invention to provide a multiple RF return pad contact detection system for use during electrosurgical activation which achieves the above objectives.
SUMMARY
A multiple RF return pad contact detection system is disclosed which is adaptive to different physiological characteristics of patients, without being susceptible to electrosurgical current interference. The detection system includes interference or measurement interaction between components of the detection system which can measure or sense the contact resistance or impedance between the patient and pairs of RF return pads or electrodes when multiple pairs of RF return pads are utilized. Due to the high current frequently needed during electrosurgery, such as during tissue ablation, the detection system eliminates or minimizes the risk of measurement interaction between the RF return pad pairs.
The circuitry of the multiple RF return pad contact detection system is preferably provided within an electrosurgical generator for controlling the generator according to various measurements, such as the contact resistance or impedance between the patient and pairs of RF return pads or return electrodes. The system allows for the independent and simultaneous measurement of the pad contact impedance for each pair of RF return pads. If the impedance of any pad pair is above a predetermined limit, the system turns off or reduces the electrosurgical output of the electrosurgical generator to prevent excess heating.
The system eliminates or minimizes interference or measurement interaction between the pad pairs by providing a different signal source frequency for each pad contact pair, but a frequency which matches an associated series resonant network frequency. The current that flows in the series resonant network is a direct reflection or function of the pad impedance of the corresponding pad pair. Since the two resonant networks are tuned to different frequencies, there is minimal interaction, if any, within the system, thus reducing the chances of inaccurate measurements.
The system could be modified by providing a multiplexer to multiplex the measurements corresponding to each pad contact pair to eliminate or minimize measurement interaction and also minimize hardware resources.
Further features of the multiple RF return pad contact detection system of the invention will become more readily apparent to those skilled in the art from the following detailed description of the apparatus taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments of the invention will be described herein below with reference to the drawings wherein:
FIG. 1 is a schematic diagram of the multiple RF return pad contact detection system in accordance with a preferred embodiment of the invention; and
FIG. 2 is a graph illustrating the operation of the pad contact impedance measurement subsystem of FIG. 1 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference should be made to the drawings where like reference numerals refer to similar elements. Referring to FIG. 1 , there is shown a schematic diagram of the multiple RF return pad contact detection system 100 of the present invention wherein electrosurgical generator 10 includes known circuitry such as a radio frequency oscillator 12 and an output amplifier 14 which generate an electrosurgical current. This current is applied to a patient (not shown) via an active electrode 16 . The electrosurgical current is returned to the generator 10 via pad contact pairs or return electrode pairs 18 a , 18 b having pads or electrodes 20 a , 20 b and 22 a , 22 b and a corresponding two conductor patient cable 24 a , 24 b having leads 26 and 28 . Two capacitors 32 and 34 are connected across each of the secondary windings 40 a , 40 b of transformer 38 a , 38 b.
Each primary winding 36 a , 36 b is connected to a corresponding a.c. signal source 42 a , 42 b and a series resonant network 44 a , 44 b . The purpose of each series resonant network 44 a , 44 b is to produce a current (i.e., left and right current senses) which is a function of the impedance between pads or electrodes 20 a , 20 b and 22 a , 22 b.
The system 100 eliminates or minimizes interference or measurement interaction between the pads 20 a , 20 b and 22 a , 22 b , while allowing for the independent and simultaneous measurement of the pad contact impedance for each pair of RF return pads by having each a.c. signal source 42 a , 42 b provide a different signal source frequency for its corresponding pad contact pair. The frequency of each series resonant network 44 a , 44 b is tuned to match the frequency of the current produced by its associated a.c. signal source 42 a , 42 b.
Accordingly, the frequency of one of the series resonant networks 44 a is different from the frequency of the other series resonant network 44 b . Hence, there is minimal interaction, if any, between the left and right circuitry of the system 100 , especially the two contact pad pairs 18 a , 18 b . This essentially eliminates inaccurate or confusing measurements.
Additionally, the frequency of the electrosurgical current produced by the electrosurgical generator 10 is substantially different from that of the current produced by the a.c. signal sources 42 a , 42 b.
The current that flows in each series resonant network 44 a , 44 b , i.e., left and right current senses, is a direct reflection or function of the pad impedance of the corresponding pad contact pair 18 a , 18 b according to the physics of a series resonant network. Each series resonant network 44 a , 44 b is an RCL network or a combination of R (resistance), L (inductance) and C (capacitance). In a preferred embodiment of the series resonant networks 44 a , 44 b , the inductive component for each network is integrated into the respective transformer 38 a , 38 b.
The frequency response of a series resonant network has a maximum resonant frequency f R . At the resonant frequency, the series resonant network has the minimum impedance, as opposed to a parallel resonant network which has the maximum impedance at the resonant frequency, and the phase angle is equal to zero degrees. The total impedance of a series resonant network is Z T +jX L −jX C =R+j(X L −X C ). At resonance: X L =X C , f R =1/(2πsqrtLC), Z T =R, and V L =V C . The resonance of a series resonant network occurs when the inductive and capacitive reactances are equal in magnitude but cancel each other because they are 180 degrees apart in phase.
The left and right current senses are applied to pad contact impedance measurement subsystem 46 which determines whether the impedance measurements between pads or return electrodes 20 a , 20 b and 22 a , 22 b are within a desired range. The range is preferably adaptable to the physiological characteristics of the patient. If at least one of the impedance measurements is not within a desired range, an inhibit signal is applied over a line 48 to internally disable the electrosurgical generator 10 (or reduce the RF output therefrom) to prevent excess heating.
U.S. Pat. Nos. 4,416,276 and 4,416,277 describe a method for determining the desired range according to the physiological characteristics of the patient, the entire contents of these patents is incorporated herein by reference.
Preferably, the desired range for which the impedance must fall between return electrodes 20 a , 20 b and 22 a , 22 b is about 20 to about 144 ohms. If not, the electrosurgical generator 10 is disabled. Thus, in one method of operation of the present invention, the lower limit is fixed at the nominal value of 20 ohms, thus reducing the onset of patient injury as a result of stray current paths which may surface if a contact pad or electrode is applied to a surface other than the patient. The upper limit is set to avoid such problems as those mentioned hereinbefore, i.e., tenting, incorrect application site, gel drying, etc.
In accordance with an important aspect of the invention, the upper limit is adjustable from the absolute maximum (typically about 144 ohms) downward to as low as typically 20 ohms to thereby provide for automatic adaptiveness to the physiological characteristics of the patient. This provides the multiple RF return pad contact detection system 100 of the present invention with significantly more control over the integrity of the RF pad contact or electrode connections without limiting the range of patient types with which the multiple RF return pad contact detection system 100 may be used or burdening the operator with additional concerns.
That is, the physiological characteristics can vary significantly from patient to patient and from one location site for the pad pairs to another. Thus, patients may vary in their respective amounts of adipose tissue (which is one determining factor in the impedance measurement between the various pads) without effecting the detection system. Further, for a particular patient, one location site may be more fatty, hairy or scarred than another. Again, this does not reduce the effectiveness of the system, i.e., all of these factors typically affect the impedance measured between pads 20 a , 20 b and 22 a , 22 b and thus concern the operator as to which site is optimal for a particular patient. Such concerns are eliminated in accordance with the present invention by providing for automatic adaptability to the physiological characteristics of the patient.
Reference should now be made to FIG. 2 which is a graph illustrating the operation of pad contact impedance measurement subsystem 46 .
During operation, the desired impedance range (that is, the acceptable range of the impedance detected between pads 20 a , 20 b and 22 a , 22 b ) is preset when the power is turned on to an upper limit of, for example, 120 ohms and a lower limit of, for example, 20 ohms as can be seen at time T=0 seconds in FIG. 2 . If the monitored impedance for any pad contact pair is determined to be outside of this range (T=A seconds) by comparing the current sense signal (or a signal derived there from) with a reference signal (e.g., a signal equal to 120 ohms or 20 ohms) using comparator circuitry (e.g., when a pad pair or any single contact pad is not affixed to the patient) an alert will be asserted and the electrosurgical generator 10 will be disabled over line 48 .
The impedance between two contact pads of a contact pad pair at any instant is designated the return RF electrode monitor (REM) Instantaneous Value (RIV) in FIG. 2 . When the REM impedance enters the range (T=B seconds) bounded by the Upper Limit (UL) and the Lower Limit (LL), a timing sequence begins. If after five seconds the RIV is still within range (T=C seconds), the alert condition will cease and the REM impedance value is stored in memory. This is designated as REM Nominal Value (RNV). The upper limit is then reestablished as 120% of this amount. The 80 ohm RIV shown in FIG. 2 causes the upper limit to be at 96 ohms. This feature of the invention is particularly important because it is at this time (T=C seconds) that adaptation is initially made to the physiological characteristics of the patient. Note if the RIV were to exceed 96 ohms at a time between T=C and T=F seconds (while the upper limit is 96 ohms), the alert will be asserted and the electrosurgical generator 10 disabled.
However, if the upper limit had not been adjusted to 96 ohms, the alert would not have been asserted until after the RIV exceeded the initial 120 ohms upper limit as determined by the comparator circuitry, thus possibly heating one or both of the pads 20 a , 20 b and 22 a , 22 b . This situation is of course exacerbated if the patient's initial RIV within the preset 20 to 120 ohm range is 30 ohms.
An initial RIV of 10 ohms within the preset range of 20 to 120 ohms sets an upper limit of 144 ohms.
In accordance with another aspect of the invention, it has been observed that the impedance between contact pads of contact pad pairs decreases over a relatively long period, such as a number of hours. Since many surgical procedures can extend a number of hours, this effect is also taken into consideration in the present invention. Accordingly, RIV is continuously monitored and any minima in REM impedance (e.g., a downward trend followed by a constant or upward trend in REM impedance) initiates a new five second timing interval (T=E seconds) at the end of which the RNV is updated to the RIV if the RIV is lower (T=F seconds). The REM upper limit of 120% of RNV is re-established at this time. The five second interval causes any temporary negative change in REM impedance (T=D seconds) to be disregarded. Operation will continue in this manner provided RNV does not exceed the upper limit of 120% RNV or drop below the lower limit of 20 ohms. Exceeding the upper limit (T=G seconds) causes an alert and the electrosurgical generator 10 is disabled. It will remain in alert until the RIV drops to 115% of RNV or less (T=H seconds) or until the system 100 is reinitialized. RIV dropping to less than 20 ohms (T=I seconds) causes a similar alert which continues until either the RIV exceeds 24 ohms (T=J seconds) or the system 100 is reinitialized. The hysteresis in the limits of the REM range (that is, the changing of the upper limit to 115% of RNV and the lower limit to 24 ohms in the previous examples) prevents erratic alerting when RIV is marginal.
It should be noted in the example of FIG. 2 that the alert actually does not turn off when RIV returns to a value greater than 24 ohms because the pad pairs are removed before 5 seconds after T=J seconds elapse. Thus, the alarm stays on due to the removal of the pad contact pairs 18 a , 18 b.
Removing the pad contact pairs 18 a , 18 b from the patient or unplugging the cables 26 , 28 from the electrosurgical generator 10 (T=K seconds) for more than one second causes the system 100 to be reinitialized to the original limits of 120 and 20 ohms. This permits a pad to be relocated or replaced (T=L seconds) without switching the electrosurgical generator 10 off. The RIV at the new location is 110 ohms and 120% RNV is 132 ohms. Thus, as described above, this is the one time (whenever RIV enters the 20 to 120 ohms range (either as preset during power on or as reinitialized as at T=K seconds) for the first time) that the upper limit can be raised during the normal REM cycle. Otherwise, it is continually decreased to adapt to the decreasing RIV impedance with the passage of time.
The preferred implementation of the foregoing FIG. 2 operation of the pad contact impedance measurement subsystem 46 is effected by a set of programmable instructions configured for execution by a microprocessor.
The system 100 could be modified by providing a multiplexer to multiplex the measurements corresponding to each pad contact pair 18 a , 18 b to eliminate or minimize measurement interaction and also minimize hardware resources.
Other pad contact pair arrangements can be provided in the system 100 of the present invention besides the pad pair arrangements shown in FIG. 1 . For example, ten pad contact pairs 18 can be provided and connected to electrosurgical generator 10 by cables 26 and 28 , where the corresponding a.c. signal source 42 and series resonant network 44 corresponding to each pad contact pair 18 are tuned to the same frequency which is different from the frequency of the other a.c. signal sources 42 and series resonant networks 44 .
It is provided that the system 100 of the present invention allows for impedance comparisons to be performed between pad pairs. Therefore, if the pad pairs are placed symmetrically on the patient, i.e., left leg and right leg, comparison of the contact impedance can provide another degree of detection and safety.
Although the subject apparatus has been described with respect to preferred embodiments, it will be readily apparent to those having ordinary skill in the art to which it appertains that changes and modifications may be made thereto without departing from the spirit or scope of the subject apparatus.
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A multiple RF return pad contact detection system is provided which is adaptive to different physiological characteristics of patients without being susceptible to electrosurgical current interference (e.g., interference or measurement interaction between components of the detection system). The detection system can measure or sense the contact resistance or impedance between the patient and pairs of RF return pads or return electrodes where multiple pairs of RF return pads are utilized due to the high current frequently needed during electrosurgery while eliminating or minimizing the risk of measurement interaction between the RF return pad pairs. The system allows for the independent and simultaneous measurement of the pad contact impedance for each pair of RF return pads. If the impedance of any pad pair is above a predetermined limit, the system turns off or reduces the electrosurgical output of the electrosurgical generator to prevent excess heating. The system eliminates or minimizes interference or measurement interaction between the pad pairs by providing a different signal source frequency for each pad contact pair, but a frequency which matches an associated series resonant network frequency. The current that flows in the series resonant network is a direct reflection or function of the pad impedance of the corresponding pad pair.
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RELATED APPLICATION
This application claims priority to U.S. Provisional Application Ser. No. 61/912,517, filed Dec. 5, 2013, which is incorporated herein by reference.
TECHNICAL FIELD
This application is generally related to stimulation leads, and in particular to stimulation leads with segmented electrodes and methods of fabrication.
BACKGROUND INFORMATION
Deep brain stimulation (DBS) refers to the delivery of electrical pulses into one or several specific sites within the brain of a patient to treat various neurological disorders. For example, deep brain stimulation has been proposed as a clinical technique for treatment of chronic pain, essential tremor, Parkinson's disease (PD), dystonia, epilepsy, depression, obsessive-compulsive disorder, and other disorders.
A deep brain stimulation procedure typically involves first obtaining preoperative images of the patient's brain (e.g., using computer tomography (CT) or magnetic resonance imaging (MRI)). Using the preoperative images, the neurosurgeon can select a target region within the brain, an entry point on the patient's skull, and a desired trajectory between the entry point and the target region. In the operating room, the patient is immobilized and the patient's actual physical position is registered with a computer-controlled navigation system. The physician marks the entry point on the patient's skull and drills a burr hole at that location. Stereotactic instrumentation and trajectory guide devices are employed to control the trajectory and positioning of a lead during the surgical procedure in coordination with the navigation system.
Brain anatomy typically requires precise targeting of tissue for stimulation by deep brain stimulation systems. For example, deep brain stimulation for Parkinson's disease commonly targets tissue within or close to the subthalamic nucleus (STN). The STN is a relatively small structure with diverse functions. Stimulation of undesired portions of the STN or immediately surrounding tissue can result in undesired side effects. Mood and behavior dysregulation and other psychiatric effects have been reported from stimulation of the STN in Parkinson's patients.
To avoid undesired side effects in deep brain stimulation, neurologists often attempt to identify a particular electrode for stimulation that only stimulates the neural tissue associated with the symptoms of the underlying disorder while avoiding use of electrodes that stimulate other tissue. Also, neurologists may attempt to control the pulse amplitude, pulse width, and pulse frequency to limit the stimulation field to the desired tissue while avoiding other tissue.
As an improvement over conventional deep brain stimulation leads, leads with segmented electrodes have been proposed. Conventional deep brain stimulation leads include electrodes that fully circumscribe the lead body. Leads with segmented electrodes include electrodes on the lead body that only span a limited angular range of the lead body. The term “segmented electrode” is distinguishable from the term “ring electrode.” As used herein, the term “segmented electrode” refers to an electrode of a group of electrodes that are positioned at approximately the same longitudinal location along the longitudinal axis of a lead and that are angularly positioned about the longitudinal axis so they do not overlap and are electrically isolated from one another. For example, at a given position longitudinally along the lead body, three electrodes can be provided with each electrode covering respective segments of less than 120° about the outer diameter of the lead body. By selecting between such electrodes, the electrical field generated by stimulation pulses can be more precisely controlled and, hence, stimulation of undesired tissue can be more easily avoided.
Implementation of segmented electrodes are difficult due to the size of deep brain stimulation leads. Specifically, the outer diameter of deep brain stimulation leads can be approximately 0.06 inches or less. Fabricating electrodes to occupy a fraction of the outside diameter of the lead body and securing the electrodes to the lead body can be quite challenging.
SUMMARY
In some embodiments, a method for fabricating a neurostimulation stimulation lead comprises: providing a plurality of ring components and hypotubes in a mold; molding the plurality of ring components and the hypotubes to form a stimulation tip component for the stimulation lead; and forming segmented electrodes from the ring components after performing the molding. The hypotubes may be welded to the electrodes before placement within a mold for an injection molding process. According to any of the discussed embodiments, the method further comprises applying a first weld and a second weld to attach each hypotube to a corresponding ring component. The molding process fills the interstitial spaces with suitable insulative material.
According to any of the discussed embodiments, the neurostimulation lead is adapted for long term implant within a patient. In one embodiment, the neurostimulation lead is a deep brain stimulation lead. The neurostimulation lead may comprise a suitable configuration of segmented electrodes (four rows of two segmented electrodes, two rows of four segmented electrodes, or two rows of three segmented electrodes with two conventional ring electrodes as example configurations). According to any of the discussed embodiments, the neurostimulation lead may comprise a non-symmetric hour-glass radial marker.
According to any of the discussed embodiments, the method further comprises: providing a pre-molded frame component with multiple lumens about the plurality of hypotubes, wherein the frame is placed about the plurality of hypotubes before the molding process is performed to retain the plurality of hypotubes at respective angular positions during the molding process. The re-molding frame structure is integrated within the stimulation tip component by the molding process. The pre-molded frame may be fabricated using a suitable biocompatible polymer material. According to any of the discussed embodiments, the stimulation tip components may employ a relatively stiff polymer material (e.g., shore 75D) while polymer material of the lead body is relatively less stiff (e.g., shore 55D).
According to any of the discussed embodiments, the plurality of hypotubes comprise different lengths for multiples ones or all of the plurality of hypotubes. The hypotubes extend from the molded portion of the stimulation or terminal tip by respective lengths. The different lengths facilitate subsequent connection of the hypotubes to conductor wires of a lead body in a correct order.
According to any of the discussed embodiments, an insulative coating is disposed on each hypotube of the plurality of hypotubes. The insulative coating may be a parylene material (one or more respective polyxylylene polymers). Weld operations may be performed on the coated hypotubes to mechanically and electrically connect the hypotubes to various other components of the neurostimulation lead. For example, the conductor wires of a lead body of the neurostimulation lead may be welded to the coated hypotubes.
According to any of the discussed embodiments, the method further comprises providing insulative material over an exposed portion of the plurality hypotubes after connection to conductor wires of a lead body and reflowing the insulative material to enclose the previously exposed portion of the plurality of hypotubes and to integrate a stimulation and/or connector tip component with the lead body. The insulative material may be provided in a “clam-shell” form to facilitate wrapping around the connection region between the stimulation or terminal tip and the lead body. The insulative material may be a suitable reflowable polymer material.
According to any of the discussed embodiments, each ring component may comprise a step-down region. The step-down region is secured underneath the surface of the neurostimulation lead formed by the insulative material provided during the molding process. The roughness of the surface of step-down region may be increased by bead-blasting to facilitate bonding or adhesion to the insulative material provided during the molding process. Also, the inner surface of the ring components may be similarly processed to facilitate adhesion to the insulative material provided during the molding process.
According to any of the discussed embodiments, the hypotubes are connected to wires of a lead body of the neurostimulation lead. The method further comprises twisting the lead body from a first configuration with linearly arranged conductor wires to obtain a second configuration with helically arranged conductor wires. The method further comprises heating the lead body to retain the helical arrangement of conductor wires in the finished neurostimulation lead. The twisting may be performed before or after connection to the hypotubes.
In some embodiments, a neurostimulation lead is fabricated using any of the methods discussed herein. In some embodiments, a neurostimulation system includes an implantable pulse generator (IPG) and one or more neurostimulation leads fabricated using any of the methods discussed herein.
The foregoing and other aspects, features, details, utilities and advantages of the present disclosure will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B depict a stimulation tip component shown in respective views according to some representative embodiments.
FIGS. 2A and 2B depict a terminal end component according to respective views according to some representative embodiments.
FIGS. 3A-3C depict a lead body component according to some representative embodiments.
FIGS. 4A-4F depict respective components of a stimulation tip component according to some representative embodiments.
FIG. 5 depicts an additional view of a terminal end component according to some representative embodiments.
FIG. 6 depicts integration of a stimulation tip component with a lead body component according to some representative embodiments.
FIG. 7 depicts a finished stimulation lead within a neurostimulation or other active medical device system according to some embodiments.
FIG. 8 depicts a flowchart of operations for fabrication of a stimulation end component according to one representative embodiment.
FIG. 9 depicts a flowchart for operations for joining a stimulation end component to a lead body component according to one representative embodiment.
FIG. 10 depicts a plurality of different marker designs that permit the orientation of a stimulation lead with segmented electrodes to be determined post-implant.
FIG. 11 depicts the orientation of a lead with segmented electrodes and an orientation marker according to one representative embodiment matched against corresponding images of the lead.
FIG. 12 depicts further images of segmented leads with markers according to some representative embodiments.
DETAILED DESCRIPTION
The present application is generally related to a process for fabricating a stimulation lead comprising multiple segmented electrodes. In one preferred embodiment, the lead is adapted for deep brain stimulation (DBS). In other embodiments, the lead may be employed for any suitable therapy including spinal cord stimulation (SCS), peripheral nerve stimulation, peripheral nerve field stimulation, dorsal root or dorsal root ganglion stimulation, cortical stimulation, cardiac therapies, ablation therapies, etc.
In some representative embodiments, multiple components are fabricated and assembled to form a stimulation lead including segmented electrodes. Referring to FIGS. 1A and 1B , stimulation end component 100 is shown in respective views. In one embodiment, stimulation end component 100 is fabricated by molding the respective components using a suitable biocompatible polymer to form an integrated assembly. In one embodiment, injection molding is the process selected for fabrication of stimulation end component 100 , although any suitable molding technique may be employed. The various components include a plurality of electrodes and hypotubes. The electrodes are connected to a plurality of hypotubes. The stimulation end component 100 may also include a radio-opaque marker to permit the orientation of the lead to be determined post-implant using suitable medical imaging. Stimulation end component 100 preferably includes a plurality of segmented electrodes. In one embodiment, a distal ring electrode, two rows of three segmented electrodes, and a proximal ring electrode are provided, although any suitable electrode configuration may be selected. One other possible electrode configuration includes two rows of four segmented electrodes. Another possible electrode configuration includes four rows of two segmented electrodes.
FIGS. 2A and 2B depict terminal end 200 according to respective views. Terminal end component 200 may be fabricated in a substantially similar manner to stimulation end component 100 using suitable molding techniques. Terminal end component 200 may preferably comprise ring contacts for placement within the header of an implantable pulse generator (IPG). Terminal end component 200 may also comprise a non-active contact ring for use with a set screw and/or contact with an initial seal element within the header of the IPG. Terminal end component 200 preferably comprises a stylet guide and central lumen for the stylet.
FIGS. 3A and 3B depict lead body component 300 . In one embodiment, a multi-lumen component of insulative material is initially molded or otherwise suitably fabricated. Conductors are placed within the various lumens as shown in FIGS. 3A and 3B . The conductors may extend from the distal and proximal ends of the body of insulative material. A central lumen is also provided in lead body component 300 for use of the finished stimulation lead with a stylet. In some embodiments, after placement of the conductor wires, lead body component 300 is twisted one or more times and subjected to heating (as shown in FIG. 3C ). By heat setting a twist configuration to the lead body component 300 , transfer of bending at one end of lead body component 300 to the other end of lead body component 300 is prevented. Preventing bend and other deformation transfers from occurring may be helpful during handling of the finished lead during an implant procedure.
FIGS. 4A-4D depict components of stimulation end component 100 according to some embodiments. In FIG. 4D , ring component 450 is shown. Ring component 450 is a substantially annular structure of suitable conductive material. Ring component 450 includes one or more step-down regions 451 where the outer diameter is reduced. The step-down regions may permit ring component 450 to be more securely integrated within the body of the stimulation end component 100 in the molding process. That is, the step-down regions 451 may be disposed below the outer surface of the insulative material after molding occurs. Also, step-down regions 450 may be bead blasted to increase the roughness of the surface of the electrodes to improve bonding or adhesion to the insulative material. Also, the inner diameter (not shown) of ring component 450 may be similar processed. Other techniques for application of abrasive materials to roughen the respective surfaces may be alternatively applied. The increase in surface roughness may further secure the integration of the metal components with the insulative material provided during the molding process. Additionally, ring component 450 may comprise longitudinal grooves or cuts (shown in FIG. 4F ) along the inner diameter of component 450 to facilitate separation of the component 450 into multiple segmented electrodes by a grinding process or other suitable processing. The reduced wall thickness along such grooves permits separation during grinding operations as detailed in U.S. patent Ser. No. 12/873,838, filed Sep. 1, 2010 (published as U.S. Patent Pub. No. 2011/0047795) which is incorporated herein by reference.
FIG. 4A depicts component 410 which includes the ring components 450 (before grinding operations), ring electrodes, and the hypotubes integrated using molded insulative material. Component 410 is subjected to suitable grinding operations to provide stimulation tip component 420 in which the grinding produces the segmented electrodes from ring components 450 . Pre-molded frame 425 (shown individually in FIG. 4C ) is placed over a portion of the hypotubes as shown in FIG. 4E to form stimulation end component 100 . Frame 425 may provide stability to hypotubes within the interior of the finished stimulation lead and prevent hypotubes from migrating to the outer surface of the stimulation lead. Also, frame 425 may ensure that hypotubes are maintained in a regular angular pattern to facilitate connection with other portions of the stimulation lead. A portion of hypotubes may preferably remain exposed to facilitate subsequent lead fabrication operations. Also, the lengths of the hypotubes may be preferably staggered as shown in FIG. 4E . The difference in length of the respective hypotubes permits ready identification of the connection of a specific hypotube to a corresponding electrode to facilitate further integration operations for fabrication of the stimulation lead.
FIG. 5 depicts an additional view of terminal end component 500 . As discussed previously, terminal end component 500 may be fabricated in substantially the same manner as stimulation end component 100 . Terminal end component 500 may include a hypotube configuration (i.e., varied lengths of hypotubes) that mirrors the arrangement of hypotubes on stimulation end component 100 to facilitate the lead fabrication process. Terminal end component 500 may include a suitable frame component surrounding the hypotubes. Further, terminal end component 500 may include an additional contact which is not connected to a hypotube. The additional contact may be employed for use with a set-screw in the header of an extension and/or IPG.
FIG. 6 depicts integration of stimulation end component 100 with lead body component 300 . Lead body component 300 is placed next to “gear” component 650 . Gear component 650 may be fabricated from suitable biocompatible material such as PEEK or ETFE. Gear component 500 comprises a plurality of grooves or channels for the conductors of lead body component 300 and the hypotubes of stimulation end component 100 . The conductors of lead body component 300 are placed within the hypotubes and suitable welding operations are performed (e.g., laser welding). Clamshell component 610 is preferably placed over the exposed connection region of conductors and hypotubes. Clamshell component 610 is preferably fabricated from a reflowable (e.g., a biocompatible polyurethane or thermoplastic polycarbonate urethane) insulative material. The material of component 610 is selected to possess a lower flow temperature than of gear component 650 . When reflow operations occur, gear component 650 retains the hypotubes and/or conductors in place and prevents mutual contact between such conductive material. Thereby, shorting between such components is prevented.
Similar operations may occur to connect the other end of lead body component 300 to terminal end component 200 to form the stimulation lead.
FIG. 7 depicts a finished stimulation lead within a neurostimulation or other active medical device system according to some embodiments. Neurostimulation system 700 includes pulse generator 720 and one or more stimulation leads 701 . Examples of commercially available pulse generator include the EON™, EON MINI™, LIBRA™, and BRIO™ pulse generators available from St. Jude Medical, Inc. Other active medical devices could be employed such as pacemakers, implantable cardioverter defibrillator, gastric stimulators, functional motor stimulators, etc. Pulse generator 720 is typically implemented using a metallic housing that encloses circuitry for generating the electrical pulses for application to neural tissue of the patient. Control circuitry, communication circuitry, and a rechargeable battery (not shown) are also typically included within pulse generator 720 . Pulse generator 720 is usually implanted within a subcutaneous pocket created under the skin by a physician.
As fabricated according to techniques described herein, lead 701 is electrically coupled to the circuitry within pulse generator 720 using header 710 . Lead 701 includes terminals (not shown) that are adapted to electrically connect with electrical connectors (e.g., “Bal-Seal” connectors which are commercially available and widely known) disposed within header 710 . The terminals are electrically coupled to conductors (not shown) within the lead body of lead 701 . The conductors conduct pulses from the proximal end to the distal end of lead 701 . The conductors are also electrically coupled to electrodes 705 to apply the pulses to tissue of the patient. Lead 701 can be utilized for any suitable stimulation therapy. For example, the distal end of lead 701 may be implanted within a deep brain location or a cortical location for stimulation of brain tissue. The distal end of lead 701 may be implanted in a subcutaneous location for stimulation of a peripheral nerve or peripheral nerve fibers. Alternatively, the distal end of lead 701 positioned within the epidural space of a patient. Although some embodiments are adapted for stimulation of neural tissue of the patient, other embodiments may stimulate any suitable tissue of a patient (such as cardiac tissue). An “extension” lead (not shown) may be utilized as an intermediate connector if deemed appropriate by the physician.
Electrodes 705 include multiple segmented electrodes. The use of segmented electrodes permits the clinician to more precisely control the electrical field generated by the stimulation pulses and, hence, to more precisely control the stimulation effect in surrounding tissue. Electrodes 705 may also include one or more ring electrodes and/or a tip electrode. Any of the electrode assemblies and segmented electrodes discussed herein can be used for the fabrication of electrodes 705 . Electrodes 705 may be utilized to electrically stimulate any suitable tissue within the body including, but not limited to, brain tissue, tissue of the spinal cord, peripheral nerves or peripheral nerve fibers, digestive tissue, cardiac tissue, etc. Electrodes 705 may also be additionally or alternatively utilized to sense electrical potentials in any suitable tissue within a patient's body.
Pulse generator 720 preferably wirelessly communicates with programmer device 750 . Programmer device 750 enables a clinician to control the pulse generating operations of pulse generator 720 . The clinician can select electrode combinations, pulse amplitude, pulse width, frequency parameters, and/or the like using the user interface of programmer device 750 . The parameters can be defined in terms of “stim sets,” “stimulation programs,” (which are known in the art) or any other suitable format. Programmer device 750 responds by communicating the parameters to pulse generator 720 and pulse generator 720 modifies its operations to generate stimulation pulses according to the communicated parameters.
FIG. 8 depicts a flowchart of operations for fabrication of a stimulation end component according to one representative embodiment. In 801 , pre-cut hypotubes are welded to electrodes that include singulation (e.g., grooves) and retention features (step-down regions). In some embodiments, the hypotubes are coated with insulative material before being welded to the electrodes. In one embodiment, a suitable thin coat (e.g., approximately 12 μm) of parylene is provided over each hypotube and the coated hypotubes are welded to the electrodes. The thin coating of parylene permits electrical isolation to be maintained between the various conductive components. The thin coating of parylene prevents shorting between respective hypotubes and other electrically conductive components. Further, it is has been determined by the present inventors that the thin coating of parylene does not affect the integrity of the subsequently created weld points between the hypotubes and other conductive components. In certain embodiments, the rings/electrode components may be additionally or alternatively coated with a thin layer of insulative material (e.g., parylene).
In some embodiments, multiple weld operations are provided for each hypotube. In one embodiment, a first weld is provided for each hypotube at the proximal end of its ring component and a second weld is provided for each hypotube at the distal end of its ring component. The first and second welds may improve the integrity of the connection between the hypotubes and the ring components. Pushing and pulling of the hypotubes may occur by the injection of insulative material during the molding process. This arrangement may cause the forces applied by the injection process to be placed on the first weld while maintaining the mechanical and electrical integrity of the second weld.
In 802 , operations to load and shrink insulation onto hypotubes are performed. In 803 , hypotubes are loaded into pre-molded frame component. The frame component may comprise an annular structure with multiple lumens to accommodate each hypotube. In 804 , the subassembly and marker are loaded into a suitable mold and injection molding operations are performed to provide BIONATE™ or other suitable insulative material under the electrodes. After molding, the assembly is subjected to grinding to obtain the intended outer diameter size ( 805 ). In 806 , annealing occurs. The terminal end component may be fabricated in a substantially similar manner.
FIG. 9 depicts a flowchart for operations for joining a stimulation end component to a lead body component according to one representative embodiment. In 901 , conductor cable ends are ablated to expose conductive material from insulative sheaths about the conductors. In one embodiment, one or more of the conductors are coated with a suitable dye material or other colorant to facilitate identification of a specific channel in the finished stimulation tip component). In 902 , the cables are strung through lumens of a lead body. In 903 , a PEEK or other extrusion or molded component (see e.g., component 650 in FIG. 6 ) is inserted between the hypotubes to hold the hypotubes in place. In 904 , cables are inserted into the hypotubes and laser welded. In 905 , a “clamshell” of BIONATE™ (thermoplastic polycarbonate urethane) material or other reflowable insulative material is loaded over the joint between the components and reflow operations are performed. The reflow operations may include providing a FEP shrink wrap and applying sufficient heat as is known in the art of lead fabrication. The terminal end component may be joined to the lead body component in a substantially similar manner.
FIG. 10 depicts a plurality of different marker designs that permit the orientation of a stimulation lead with segmented electrodes to be determined post-implant. One marker may be provided at a distal or tip of the stimulation lead. Additionally or alternatively, another marker may be provided proximal to the electrodes of the stimulation lead about the outer surface of the lead body. FIG. 11 depicts the orientation of a lead with segmented electrodes and an orientation marker according to one representative embodiment matched against corresponding images of the lead. FIG. 12 depicts further images of segmented leads with markers according to some representative embodiments.
Although certain embodiments of this disclosure have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this disclosure. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the disclosure. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the disclosure as defined in the appended claims.
When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above constructions without departing from the scope of the disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
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In one embodiment, a method for fabricating a neurostimulation stimulation lead comprises: providing a plurality of ring components and hypotubes in a mold; placing an annular frame with multiple lumens over distal ends of the plurality of hypotubes to position a portion of each hypotube within a respective lumen of the annular frame; molding the plurality of ring components and the hypotubes to form a stimulation tip component for the stimulation lead, wherein the molding fills interstitial spaces between the plurality of ring components and hypotubes with insulative material; and forming segmented electrodes from the ring components after performing the molding.
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COPYRIGHT NOTICE
[0001] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by any one of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright whatsoever.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to Web Services Invocation Framework (WSIF) operations and, in particular, to exposing J2C interface properties in such operations.
[0004] 2. Description of the Related Art
[0005] Historically, Enterprise Information/integration Systems (EIS), such as legacy mainframe systems, and, more recently, commercial applications, have been at the center of modern information technology environments, providing critical data for enterprise operations. Companies have big investments in their Enterprise Information Systems. While many applications may be old, some may be new. The EIS provides the company with the quality of service required by the company. An example application, known as a “transactional” application, allows updates to be made to a bank account. Although these systems continue to be critically important to many businesses, these businesses may further rely on other applications. As these other applications are often web or wireless applications, there appears to be an increasing need to integrate web and wireless applications with legacy mainframe systems and existing commercial applications. Such integration requires the real-time exchange of information and services by a range of interested parties. The new applications, for which this integration is required, are increasingly being developed in the Java™ programming language.
[0006] As a required element of the Java™ 2 Enterprise Edition (J2EE), the Java ConnectorArchitecture (J2C) provides a standardized means to integrate Java applications with EISs (Java is a Trademark of Sun Microsystems, Inc.) J2C defines a Common Client Interface (CCI). The CCI defines a standard client Application Programming Interface (API) for application components. The CCI enables application components and Enterprise Application Integration (EAI) frameworks to drive interactions across heterogeneous ElSs using a common client API. Interfaces that are part of the CCI include “interactionSpec” and “connectionSpec”; these interfaces are further described hereinafter.
[0007] As mentioned hereinbefore, companies may have business requirements to enable web access to these services. To extend the previous example of a banking application, there may be a requirement to enable access to bank accounts over the Internet. The J2EE Connector architecture (J2C) provides an environment so that an EIS can provide a resource adapter that can plug in to any application server so that the application server can generically provide qualities of service to all resource adapters, and optionally, through the CCI, the resource adapter can implement the common client programming model for the enterprise application. Such J2C services may further be extended to be web services.
[0008] Integration of Java applications with EIS may be accomplished through the use of J2C. The Web Services Description Language (WSDL), with its extensions, allows the description of many different kinds of services: Web services, Java services, Enterprise Java Bean (EJB) services, Java Message Service (JMS) services, J2C services, etc. The Web Services Invocation Framework (WSIF—see http://ws.apache.org/wsif) provides a common way of invoking each of these services. The WSIF supports a simple Java™ API for invoking Web services. Use of the WSIF API allows clients to invoke services focusing on an abstract service description, that is, the portion of WSDL that covers port types, operations and message exchanges without referring to real protocols.
[0009] As mentioned hereinbefore, WSDL is extensible to allow the description of many types of services other than web services. With WSIF, any of these types of services may be invoked in a common fashion. However, WSIF does not expose certain J2C properties, thus constraining certain applications.
SUMMARY OF THE INVENTION
[0010] interactionSpec and connectionSpec properties are exposed as data in WSIF operations, thus WSIF support for J2C is made functionally more complete. Advantageously, exposing J2C interactionSpec and connectionSpec properties as data in a WSIF operation allows the connectionSpec and interactionSpec properties to be set dynamically on input and the interactionSpec properties to be retrieved dynamically on output.
[0011] In accordance with an aspect of the present invention there is provided a method of improving Web Services Invocation Framework support for Java 2 Enterprise Edition Java Connector Architecture comprising exposing properties of a given interface as data.
[0012] In accordance with another aspect of the present invention there is provided a method of a performing Web Services Invocation Framework operation. The method includes receiving an input message that includes a plurality of parts, determining whether any of the plurality of parts are instances of a property of a given interface and, if a given part of the plurality of parts is determined to be an instance of the property of the given interface, setting a value from the given part into the given interface, thereby exposing a property of the given interface as data. In other aspects of the present invention, a resource adapter is provided in an application sever, the resource adapter for performing this method and a computer readable medium is provided to allow a general purpose computer to perform this method.
[0013] Other aspects and features of the present invention will become apparent to those of ordinary skill 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
[0014] In the figures which illustrate example embodiments of this invention:
[0015] FIG. 1 illustrates an exemplary environment for implementation of aspects of the present invention;
[0016] FIG. 2 illustrates steps of a method carried out by a resource adapter in the environment of FIG. 1 according to an embodiment of the present invention;
[0017] FIGS. 3A-3R illustrate exemplary code for implementing WSIF Operation aspects of the present invention;
[0018] FIGS. 4A-4Q illustrate exemplary code for implementing WSIF Provider External Call Interface aspects of the present invention;
[0019] FIGS. 5A-5D illustrate exemplary code for implementing interactionSpec Property exposure aspects of the present invention;
[0020] FIGS. 6A-6D illustrate exemplary code for implementing ConnectionSpec Property exposure aspects of the present invention;
[0021] FIGS. 7A-7H illustrate exemplary code for implementing WSIF Provider Extension aspects of the present invention;
[0022] FIGS. 8A-8O illustrate exemplary code for implementing Streamable Message aspects of the present invention;
[0023] FIGS. 9A-9D illustrate exemplary code for implementing WSIF Binding Operation aspects of the present invention;
[0024] FIGS. 10A-10E illustrate an exemplary customer port type definition implementing aspects of the present invention;
[0025] FIGS. 11A-11I illustrate an exemplary binding definition implementing aspects of the present invention;
[0026] FIG. 12 illustrates an exemplary services definition implementing aspects of the present invention; and
[0027] FIGS. 13A-13H illustrate exemplary client code implementing aspects of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] FIG. 1 illustrates an exemplary environment for implementation of aspects of the present invention. In particular, a web client 102 is illustrated in communication with a web server 104 . It should be understood that this connection will typically occur over a digital communications network. Where an end user at the web client is interested in a service provided by an EIS 110 , such an interest can be indicated to the web server 104 and, in response to receiving such an indication, the web server 104 may contact an application server 106 . It is then the task of the application server 106 to interact with the EIS 110 as directed by the end user.
[0029] As mentioned hereinbefore, J2C provides an environment so that the EIS 110 can provide a resource adapter 108 that can plug in to the application server 106 so that the application server 106 can generically provide the qualities of services available from the resource adapter 108 illustrated and other EIS-specific resource adapters (not shown).
[0030] The resource adapter 108 may be loaded with methods exemplary of this invention from a software medium 112 which could be a disk, a tape, a chip or a random access memory containing a file downloaded from a remote source.
[0031] Much of the following description of interactionSpec and connectionSpec and respective properties is drawn from the Java™ 2 Platform, Enterprise Edition, v 1.3 API Specification (hereby incorporated herein by reference).
[0032] The interactionSpec property holds properties for driving an interaction with an EIS instance. The CCI specification defines a set of standard properties for an interactionSpec. An interactionSpec implementation is not required to support a standard property if that property does not apply to its underlying EIS. The interactionSpec implementation class must provide getter and setter methods for each of its supported properties. The getter and setter methods convention should be based on the Java Beans design pattern. The standard properties are as follows:
FunctionName: name of an EIS function InteractionVerb: mode of interaction with an EIS instance ExecutionTimeout: the number of milliseconds an Interaction will wait for an EIS to execute the specified function FetchSize FetchDirection MaxFieldSize ResultSetType ResultSetConcurrency
[0041] The last five standard properties are used to give hints to an Interaction instance about the ResultSet requirements.
[0042] A CCI implementation can provide additional properties beyond that described in the interactionSpec interface. Note that the format and type of the additional properties is specific to an EIS and is outside the scope of the CCI specification.
[0043] ConnectionSpec is used by an application component to pass connection request-specific properties to an interface for getting connection to an EIS instance. The CCI specification defines a set of standard properties for a ConnectionSpec. The properties are defined either on a derived interface or an implementation class of an empty ConnectionSpec interface. In addition, a resource adapter may define additional properties specific to its underlying EIS. A resource adapter is a system-level software driver that is used by a Java application to connect to an EIS. The resource adapter plugs into an application server and provides connectivity between the EIS, the application server and the enterprise application. In simpler terms, a resource adapter is the software that allows an application to access functions in an EIS.
[0044] Among others, the following standard properties are defined by the CCI specification for ConnectionSpec:
UserName: name of the user establishing a connection to an EIS instance Password: password for the user establishing a connection
[0047] interactionSpec and ConnectionSpec Properties generally need to be “exposed” to allow an application to set the values of the properties at execution time. Otherwise, the values of the properties would have to be set when the application is built.
[0048] Often the interactionSpec values may be preset. However, some scenarios require the ability to set a value or to obtain a value on output. For example, in “component managed signon”, there is a requirement of the ability to set the user name and password on the connectionSpec on input. In contrast, for “container managed signon”, a connectionSpec is not used.
[0049] ConnectionSpec properties are part of the port section of the WSDL. ConnectionSpec exposes any security information and connection parameters that are specific to the resource adapter. In the component managed signon case, an application component passes security information (example: username, password) through a ConnectionSpec instance. interactionSpec properties are part of the binding section of the WSDL.
[0050] It is known that J2C has a managed and a non-managed scenario. In the non-managed scenario the connectionSpec and interactionSpec properties are taken from an associated WSDL file. An interactionSpec object can also be exposed as a property on a proxy that is used to execute an EIS interaction.
[0051] In the managed scenario, some connectionSpec properties (UserName and Password) are exposed as an administered Java Authentication and Authorization Service (JAAS) Subject or as custom properties on an interface for getting connection to an EIS instance. interactionSpec properties are not exposed in the managed scenario.
[0052] Exposing connectionSpec properties is important for enabling component managed signon. Exposing interactionSpec properties is important because some EIS interactionSpec properties are important for the application to set or retrieve at runtime. Unfortunately, when working with WSIF J2C operations, the interactionSpec properties are part of the binding and are not exposed. A “binding” is a WSDL concept. A binding defines the concrete implementation of an abstract operation. The binding specifies the message format and protocol details of the abstract operation. In the context of a WSIF J2C operation, the binding is communicated to the resource adapter 108 in one or more messages.
[0053] To implement the exposure of the interactionSpec properties and the connectionSpec properties as data, the method typically implemented by the resource adapter 108 is altered as illustrated in FIG. 2 .
[0054] An input message is received by the resource adapter 108 from the application server 106 , causing the resource adapter 108 to perform the steps of the method 200 illustrated in FIG. 2 . The updatelnteractionSpec method provided by the EIS 110 is initially called (step 202 ) to update the interactionSpec using data from the input message. The method called updatelnteractionSpec determines whether any of the parts in the input message are instances of the interactionSpecProperty. If a part is determined to be such an instance, updatelnteractionSpec takes the value from the part and sets the value into the interactionSpec. It is then determined whether a connection is currently available (step 204 ). Where a connection is not available, the connection is considered to be “null”. If a connection is not currently available, it is determined whether any of the parts in the input message are instances of the connectionSpecProperty (step 206 ). If so, while creating a connection to the EIS 110 (step 207 ), values from each of such parts are set into the connectionSpec, which is then used when creating the connection. If no parts are instances of the connectionSpecProperty, a connection to the EIS 110 is created with no connectionSpec specified (step 208 ). In each of steps 207 and 208 , the connection to the EIS 110 is created by calling a createConnection method. If a connection is determined (step 204 ) to be currently available, or once a connection has been created (step 207 or 208 ), an interaction (i.e., a javax.resource.cci.Interaction) is created from the connection (step 209 ). An interaction execute method is then invoked (step 210 ) with the EIS 110 . The interaction is then closed (step 212 ). If the interaction execute method is an input only method, the method is complete. However, where the interaction execute method is a request response operation (determined in step 214 ), the interactionSpec is set into an output message (step 216 ) and the output message is updated (step 218 ) with specified interactionSpec properties.
[0055] Note that, in the port type section of the WSDL, the developer adds a part to the input message for each interactionSpec or connectionSpec property that is to be exposed as data. Parts are also added to the output message for each interactionSpec property that is to be exposed as data. In the binding section of the WSDL for the input and output sections of the operation, the developer then specifies how these added parts map to connectionSpec or interactionSpec properties. This mapping is then used at runtime.
[0056] As will be apparent to a person skilled in the art, the portion of the method 200 illustrated in FIG. 2 that is typically implemented by the resource adapter 108 is represented by step 209 , step 210 and step 212 .
[0057] Exemplary code operable to implement the method of FIG. 2 is illustrated in FIGS. 3A-3R as WSIFOperation_JCA.java.
[0058] The method called updatelnteractionSpec that is used in WSIFOperation_JCA.java (see FIGS. 3D and 3F ) and called at step 202 of FIG. 2 , is provided as part of exemplary code illustrated in FIGS. 4A-4Q , called WSIFProvider_ECI.java (in particular, see FIG. 4G ). The ECI acronym relates to the External Call Interface of the resource adapter 108 . The method called updateinteractionSpec determines whether any of the parts in the input message are instances of the interactionSpecProperty. If a part is determined to be such an instance, updatelnteractionSpec takes the value from the part and sets the value into the interactionSpec. The method called updatelnteractionSpec calls ECIInteractionSpecProperty, which is illustrated in FIG. 5 .
[0059] The method called createConnection that is used in WSIFOperation_JCA.java (see FIGS. 3E and 3G ) and called at step 206 of FIG. 2 is also provided as part of WSIFProvider_ECI.java (see FIG. 4L ). The method called createConnection determines whether any of the parts in the input message are instances of the connectionSpecProperty. If a part is determined to be such an instance, createConnection takes the value from the part, sets the value into the connectionSpec and uses the connectionSpec when creating the connection. If no parts are instances of the connectionSpecProperty, a connection is created with no connectionSpec specified. The method called createConnection calls ECIConnectionSpecProperty, which is illustrated in FIG. 6 .
[0060] Additionally, a method called updateOutputMessage that is used in WSIFOperation_JCA.java (see FIG. 3E ) and called at step 218 of FIG. 2 is provided as part of WSIFProvider_ECI.java (see FIG. 4K ).
[0061] A known interface called WSIFProviderJCAExtensions has been updated as shown in FIG. 7 . to include the updatelnteractionSpec, updateOutputMessage and createConnection methods.
[0062] WSIFMessage_JCAStreamable, which is illustrated in FIG. 8 , keeps the input interactionSpec and connectionSpec properties, which were provided as parts in the input message, from being sent as data to the EIS 110 . WSI FMessage_JCAStreamable also populates the parts of the output message as appropriate from the interactionSpec.
[0063] WSIFBindingOperation_JCAProperty, which is illustrated in FIG. 9 , is an interface of the methods used to get/set partName and either connectionSpec property name or interactionSpec property name.
[0064] Consider the use of an embodiment of the present invention in the following example. A message called “getCustomerRequest” is defined in Customer.wsdl (see FIGS. 10A-10E , in particular FIG. 10E ). The message definition includes identification of particular parts, including “userid”, “password” and “functionName”. An operation called “getCustomer” is also defined in Customer.wsdl. The getcustomer message receives the specific getCustomerRequest message as input and issues a getCustomerResponse message as output.
[0065] The getcustomer operation is further defined in CustomerCICSECIBinding.wsdl (see FIGS. 11A-11I ). By this further definition, the user name part and the password part are each defined as a ConnectionSpecProperty and the functionName part is defined as an InteractionSpecProperty. Thus, the user name part and the password part may be exposed on the ConnectionSpec as data and the functionName part may be exposed on the interactionSpec as data.
[0066] The definitions of exemplary definition files Customer.wsdl and CustomerCICSECIBinding.wsdl are imported into the exemplary definition file called CustomerCICSECIService.wsdl ( FIG. 12 ). The acronym CICS refers to the “Customer Information Control System”, which is a family of application servers and connectors that provides online transaction management and connectivity for applications.
[0067] Exemplary program code, CustomerProxy.java, is illustrated in FIGS. 13A-13H . Notably, CustomerProxy.java references the exemplary definition file called CustomerCICSECIService.wsdl (see FIG. 13D ) and, by doing so, thus references exemplary definition files Customer.wsdl and CustomerCICSECIBinding.wsdl. The reference to these exemplary definition files allows the exemplary program code to make reference to the getCustomer operation and the getCustomerRequest and getCustomerResponse messages (see FIG. 13C ).
[0068] As will be apparent to a person skilled in the art, exposing interactionSpec and ConnectionSpec properties as data allows the size of the commarea of a CICS external call interface to be specified, providing a performance enhancement (where a commarea is a “communications area”, which defines the input and outputfor a program). Additionally, the exposing allows a user name and a password to be passed by a resource adapter when establishing a connection, thus supporting component managed signon.
[0069] Other modifications will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.
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The invention relates to Web Services Invocation Framework (WSIF) operations. “interactionSpec” and “connectionSpec” are Java 2 Enterprise Edition Java Connector Architecture interfaces. Their properties are exposed as data in WSIF operations. Thus WSIF support for the Java 2 Enterprise Edition Java Connector Architecture is made functionally more complete.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is claims priority to U.S. Provisional Application Ser. No. 60/291,215 of Fei Mao, filed on May 15, 2001 and entitled “Biosensor Membranes Composed of Polyvinylpyridines”, which is incorporated herein in its entirety by this reference.
FIELD OF THE INVENTION
[0002] This invention generally relates to an analyte-flux-limiting membrane. More particularly, the invention relates to such a membrane composed of polymers containing heterocyclic nitrogens. The membrane is a useful component in biosensors, and more particularly, in biosensors that can be implanted in a living body.
BACKGROUND OF THE INVENTION
[0003] Enzyme-based biosensors are devices in which an analyte-concentration-dependent biochemical reaction signal is converted into a measurable physical signal, such as an optical or electrical signal. Such biosensors are widely used in the detection of analytes in clinical, environmental, agricultural and biotechnological applications. Analytes that can be measured in clinical assays of fluids of the human body include, for example, glucose, lactate, cholesterol, bilirubin and amino acids. The detection of analytes in biological fluids, such as blood, is important in the diagnosis and the monitoring of many diseases.
[0004] Biosensors that detect analytes via electrical signals, such as current (amperometric biosensors) or charge (coulometric biosensors), are of special interest because electron transfer is involved in the biochemical reactions of many important bioanalytes. For example, the reaction of glucose with glucose oxidase involves electron transfer from glucose to the enzyme to produce gluconolactone and reduced enzyme. In an example of an amperometric glucose biosensor, glucose is oxidized by oxygen in the body fluid via a glucose oxidase-catalyzed reaction that generates gluconolactone and hydrogen peroxide, whereupon the hydrogen peroxide is electrooxidized and correlated to the concentration of glucose in the body fluid. (Thomé-Duret, V., et al., Anal. Chem. 68, 3822 (1996); and U.S. Pat. No. 5,882,494 of Van Antwerp.) In another example of an amperometric glucose biosensor, the electrooxidation of glucose to gluconolactone is mediated by a polymeric redox mediator that electrically “wires” the reaction center of the enzyme to an electrode. (Csöregi, E., et al., Anal. Chem. 66, 3131 (1994); Csöregi, E., et al., Anal. Chem. 67, 1240 (1995); Schmidtke, D. W., et al., Anal. Chem. 68, 2845 (1996); Schmidtke, D. W., et al., Anal. Chem. 70, 2149 (1998); and Schmidtke, D. W., et al., Proc. Natl. Acad. Sci. U.S.A. 95, 294 (1998).)
[0005] Amperometric biosensors typically employ two or three electrodes, including at least one measuring or working electrode and one reference electrode. In two-electrode systems, the reference electrode also serves as a counter-electrode. In three-electrode systems, the third electrode is a counter-electrode. The measuring or working electrode is composed of a non-corroding carbon or a metal conductor and is connected to the reference electrode via a circuit, such as a potentiostat.
[0006] Some biosensors are designed for implantation in a living animal body, such as a mammalian or a human body, merely by way of example. In an implantable amperometric biosensor, the working electrode is typically constructed of a sensing layer, which is in direct contact with the conductive material of the electrode, and a diffusion-limiting membrane layer on top of the sensing layer. The sensing layer typically consists of an enzyme, an enzyme stabilizer such as bovine serum albumin (BSA), and a crosslinker that crosslinks the sensing layer components. Alternatively, the sensing layer consists of an enzyme, a polymeric mediator, and a crosslinker that crosslinks the sensing layer components, as in the above-mentioned “wired-enzyme” biosensor.
[0007] In an implantable amperometric glucose sensor, the membrane is often beneficial or necessary for regulating or limiting the flux of glucose to the sensing layer. By way of explanation, in a glucose sensor without a membrane, the flux of glucose to the sensing layer increases linearly with the concentration of glucose. When all of the glucose arriving at the sensing layer is consumed, the measured output signal is linearly proportional to the flux of glucose and thus to the concentration of glucose. However, when the glucose consumption is limited by the kinetics of chemical or electrochemical activities in the sensing layer, the measured output signal is no longer controlled by the flux of glucose and is no longer linearly proportional to the flux or concentration of glucose. In this case, only a fraction of the glucose arriving at the sensing layer is consumed before the sensor becomes saturated, whereupon the measured signal stops increasing, or increases only slightly, with the concentration of glucose. In a glucose sensor equipped with a diffusion-limiting membrane, on the other hand, the membrane reduces the flux of glucose to the sensing layer such that the sensor does not become saturated and can therefor operate effectively within a much wider range of glucose concentration.
[0008] More particularly, in these membrane-equipped glucose sensors, the glucose consumption rate is controlled by the diffusion or flux of glucose through the membrane rather than by the kinetics of the sensing layer. The flux of glucose through the membrane is defined by the permeability of the membrane to glucose, which is usually constant, and by the concentration of glucose in the solution or biofluid being monitored. When all of the glucose arriving at the sensing layer is consumed, the flux of glucose through the membrane to the sensing layer varies linearly with the concentration of glucose in the solution, and determines the measured conversion rate or signal output such that it is also linearly proportional to the concentration of glucose concentration in the solution. Although not necessary, a linear relationship between the output signal and the concentration of glucose in the solution is ideal for the calibration of an implantable sensor.
[0009] Implantable amperometric glucose sensors based on the electrooxidation of hydrogen peroxide, as described above, require excess oxygen reactant to ensure that the sensor output is only controlled by the concentration of glucose in the body fluid or tissue being monitored. That is, the sensor is designed to be unaffected by the oxygen typically present in body fluid or tissue. In body tissue in which the glucose sensor is typically implanted, the concentration of oxygen can be very low, such as from about 0.02 mM to about 0.2 mM, while the concentration of glucose can be as high as about 30 mM or more. Without a glucose-diffusion-limiting membrane, the sensor would become saturated very quickly at very low glucose concentrations. The sensor thus benefits from having a sufficiently oxygen-permeable membrane that restricts glucose flux to the sensing layer, such that the so-called “oxygen-deficiency problem,” a condition in which there is insufficient oxygen for adequate sensing to take place, is minimized or eliminated.
[0010] In implantable amperometric glucose sensors that employ wired-enzyme electrodes, as described above, there is no oxygen-deficiency problem because oxygen is not a necessary reactant. Nonetheless, these sensors require glucose-diffusion-limiting membranes because typically, for glucose sensors that lack such membranes, the current output reaches a maximum level around or below a glucose concentration of 10 mM, which is well below 30 mM, the high end of clinically relevant glucose concentration.
[0011] A diffusion-limiting membrane is also of benefit in a biosensor that employs a wired-enzyme electrode, as the membrane significantly reduces chemical and biochemical reactivity in the sensing layer and thus reduces the production of radical species that can damage the enzyme. The diffusion-limiting membrane may also act as a mechanical protector that prevents the sensor components from leaching out of the sensor layer and reduces motion-associated noise.
[0012] There have been various attempts to develop a glucose-diffusion-limiting membrane that is mechanically strong, biocompatible, and easily manufactured. For example, a laminated microporous membrane with mechanical holes has been described (U.S. Pat. No. 4,759,828 of Young et al.) and membranes formed from polyurethane are also known (Shaw, G. W., et al., Biosensors and Bioelectronics 6, 401(1991); Bindra, D. S., et al., Anal. Chem. 63, 1692 (1991); Shichiri, M., et al., Horm. Metab. Res., Suppl. Ser. 20, 17 (1988)). Supposedly, glucose diffuses through the mechanical holes or cracks in these various membranes. Further by way of example, a heterogeneous membrane with discrete hydrophobic and hydrophilic regions (U.S. Pat. No. 4,484,987 of Gough) and homogenous membranes with both hydrophobic and hydrophilic functionalities (U.S. Pat. Nos. 5,284,140 and 5,322,063 of Allen et al.) have been described. However, all of these known membranes are difficult to manufacture and have inadequate physical properties.
[0013] An improved membrane formed from a complex mixture of a diisocyanate, a diol, a diamine and a silicone polymer has been described in U.S. Pat. Nos. 5,777,060 (Van Antwerp), 5,786,439 (Van Antwerp et al.) and 5,882,494 (Van Antwerp). As described therein, the membrane material is simultaneously polymerized and crosslinked in a flask; the resulting polymeric material is dissolved in a strong organic solvent, such as tetrahydroforan (THF); and the resulting solution is applied onto the sensing layer to form the membrane. Unfortunately, a very strong organic solvent, such as THF, can denature the enzyme in the sensing layer and also dissolve conductive ink materials as well as any plastic materials that may be part of the sensor. Further, since the polymerization and crosslinking reactions are completed in the reaction flask, no further bond-making reactions occur when the solution is applied to the sensing layer to form the membrane. As a result, the adhesion between the membrane layer and sensing layer may not be adequate.
[0014] In the published Patent Cooperation Treaty (PCT) Application bearing International Publication No. WO 01/57241 A2, Kelly and Schiffer describe a method for making a glucose-diffusion-limiting membrane by photolytically polymerizing small hydrophilic monomers. The sensitivities of the glucose sensors employing such membranes are widely scattered, however, indicating a lack of control in the membrane-making process. Further, as the polymerization involves very small molecules, it is quite possible that small, soluble molecules remain after polymerization, which may leach out of the sensor. Thus, glucose sensors employing such glucose-diffusion-limiting membranes may not be suitable for implantation in a living body.
SUMMARY OF THE INVENTION
[0015] The present invention is directed to membranes composed of crosslinked polymers containing heterocyclic nitrogen groups, particularly polymers of polyvinylpyridine and polyvinylimidazole, and to electrochemical sensors equipped with such membranes. The membranes are useful in limiting the flux of an analyte to a working electrode in an electrochemical sensor so that the sensor is linearly responsive over a large range of analyte concentrations and is easily calibrated. Electrochemical sensors equipped with membranes of the present invention demonstrate considerable sensitivity and stability, and a large signal-to-noise ratio, in a variety of conditions.
[0016] According to one aspect of the invention, the membrane is formed by crosslinking in situ a polymer, modified with a zwitterionic moiety, a non-pyridine copolymer component, and optionally another moiety that is either hydrophilic or hydrophobic, and/or has other desirable properties, in an alcohol-buffer solution. The modified polymer is made from a precursor polymer containing heterocyclic nitrogen groups. Preferably, the precursor polymer is polyvinylpyridine or polyvinylimidazole. When used in an electrochemical sensor, the membrane limits the flux of an analyte reaching a sensing layer of the sensor, such as an enzyme-containing sensing layer of a “wired enzyme” electrode, and further protects the sensing layer. These qualities of the membrane significantly extend the linear detection range and the stability of the sensor.
[0017] In the membrane formation process, the non-pyridine copolymer component generally enhances the solubility of the polymer and may provide further desirable physical or chemical properties to the polymer or the resulting membrane. Optionally, hydrophilic or hydrophobic modifiers may be used to “fine-tune” the permeability of the resulting membrane to an analyte of interest. Optional hydrophilic modifiers, such as poly(ethylene glycol), hydroxyl or polyhydroxyl modifiers, may be used to enhance the biocompatibility of the polymer or the resulting membrane. In the formation of a membrane of the present invention, the zwitterionic moiety of the polymer is believed to provide an additional layer of crosslinking, via intermolecular electrostatic bonds, beyond the basic crosslinking generally attributed to covalent bonds, and is thus believed to strengthen the membrane.
[0018] Another aspect of the invention concerns the preparation of a substantially homogeneous, analyte-diffusion-limiting membrane that may be used in a biosensor, such as an implantable amperometric biosensor. The membrane is formed in situ by applying an alcohol-buffer solution of a crosslinker and a modified polymer over an enzyme-containing sensing layer and allowing the solution to cure for one to two days. The crosslinker-polymer solution may be applied to the sensing layer by placing a droplet or droplets of the solution on the sensor, by dipping the sensor into the solution, or the like. Generally, the thickness of the membrane is controlled by the concentration of the solution, by the number of droplets of the solution applied, by the number of times the sensor is dipped in the solution, or by any combination of the these factors. Amperometric glucose sensors equipped with diffusion-limiting membranes of the present invention demonstrate excellent stability and fast and linear responsivity to glucose concentration over a large glucose concentration range.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is an illustration of a typical structure of a section of an analyte-diffusion-limiting membrane, according to the present invention.
[0020] FIG. 2A is a schematic, side-view illustration of a portion of a two-electrode glucose sensor having a working electrode, a combined counter/reference electrode, and a dip-coated membrane that encapsulates both electrodes, according to the present invention. FIGS. 2B and 2C are schematic top- and bottom-view illustrations, respectively, of the portion of the glucose sensor of FIG. 2A . Herein, FIGS. 2A , 2 B and 2 C may be collectively referred to as FIG. 2 .
[0021] FIG. 3 is a graph of current versus glucose concentration for sensors having glucose-diffusion-limiting membranes, according to the present invention, and for sensors lacking such membranes, based on average values.
[0022] FIG. 4 is a graph of current output versus time at fixed glucose concentration for a sensor having a glucose-diffusion-limiting membrane, according to the present invention, and for a sensor lacking such a membrane.
[0023] FIG. 5 is a graph of current output versus time at different levels of glucose concentration for sensors having glucose-diffusion-limiting membranes, according to the present invention, based on average values.
[0024] FIG. 6 is a graph of current output versus time at different levels of glucose concentration, with and without stirring, for a sensor having a glucose-diffusion-limiting membrane, according to the present invention, and for a sensor lacking such a membrane.
[0025] FIG. 7A is a graph of current output versus glucose concentration for four separately prepared batches of sensors having glucose-diffusion-limiting membranes, according to the present invention, based on average values. FIGS. 7B-7E are graphs of current output versus glucose concentration for individual sensors in each of the four above-referenced batches of sensors having glucose-diffusion-limiting membranes, respectively, according to the present invention. Herein, FIGS. 7A , 7 B, 7 C, 7 D and 7 E may be collectively referred to as FIG. 7 .
DESCRIPTION OF THE INVENTION
[0026] When used herein, the terms in quotation marks are defined as set forth below.
[0027] The term “alkyl” includes linear or branched, saturated aliphatic hydrocarbons. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl and the like. Unless otherwise noted, the term “alkyl” includes both alkyl and cycloalkyl groups.
[0028] The term “alkoxy” describes an alkyl group joined to the remainder of the structure by an oxygen atom. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, tert-butoxy, and the like. In addition, unless otherwise noted, the term ‘alkoxy’ includes both alkoxy and cycloalkoxy groups.
[0029] The term “alkenyl” describes an unsaturated, linear or branched aliphatic hydrocarbon having at least one carbon-carbon double bond. Examples of alkenyl groups include ethenyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-methyl-1-propenyl, and the like.
[0030] A “reactive group” is a functional group of a molecule that is capable of reacting with another compound to couple at least a portion of that other compound to the molecule. Reactive groups include carboxy, activated ester, sulfonyl halide, sulfonate ester, isocyanate, isothiocyanate, epoxide, aziridine, halide, aldehyde, ketone, amine, acrylamide, thiol, acyl azide, acyl halide, hydrazine, hydroxylamine, alkyl halide, imidazole, pyridine, phenol, alkyl sulfonate, halotriazine, imido ester, maleimide, hydrazide, hydroxy, and photo-reactive azido aryl groups. Activated esters, as understood in the art, generally include esters of succinimidyl, benzotriazolyl, or aryl substituted by electron-withdrawing groups such as sulfo, nitro, cyano, or halo groups; or carboxylic acids activated by carbodiimides.
[0031] A “substituted” functional group (e.g., substituted alkyl, alkenyl, or alkoxy group) includes at least one substituent selected from the following: halogen, alkoxy, mercapto, aryl, alkoxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, —OH, —NH2, alkylamino, dialkylamino, trialkylammonium, alkanoylamino, arylcarboxamido, hydrazino, alkylthio, alkenyl, and reactive groups.
[0032] A “crosslinker” is a molecule that contains at least two reactive groups capable of linking at least two molecules together, or linking at least two portions of the same molecule together. Linking of at least two molecules is called intermolecular crosslinking, while linking of at least two portions of the same molecule is called intramolecular crosslinking. A crosslinker having more than two reactive groups may be capable of both intermolecular and intramolecular crosslinkings at the same time.
[0033] The term “precursor polymer” refers to the starting polymer before the various modifier groups are attached to form a modified polymer.
[0034] The term “heterocyclic nitrogen group” refers to a cyclic structure containing a sp 2 hybridized nitrogen in a ring of the structure.
[0035] The term “polyvinylpyridine” refers to poly(4-vinylpyridine), poly(3-vinylpyridine), or poly(2-vinylpyridine), as well as any copolymer of vinylpyridine and a second or a third copolymer component.
[0036] The term “polyvinylimidazole” refers to poly(1-vinylimidazole), poly(2-vinylimidazole), or poly(4-vinylimidazole).
[0037] A “membrane solution” is a solution that contains all necessary components for crosslinking and forming the membrane, including a modified polymer containing heterocyclic nitrogen groups, a crosslinker and a buffer or an alcohol-buffer mixed solvent.
[0038] A “biological fluid” or “biofluid” is any body fluid or body fluid derivative in which the analyte can be measured, for example, blood, interstitial fluid, plasma, dermal fluid, sweat, and tears.
[0039] An “electrochemical sensor” is a device configured to detect the presence of or measure the concentration or amount of an analyte in a sample via electrochemical oxidation or reduction reactions. Typically, these reactions can be transduced to an electrical signal that can be correlated to an amount or concentration of analyte.
[0040] A “redox mediator” is an electron-transfer agent for carrying electrons between an analyte, an analyte-reduced or analyte-oxidized enzyme, and an electrode, either directly, or via one or more additional electron-transfer agents. A redox mediator that includes a polymeric backbone may also be referred to as a “redox polymer”.
[0041] The term “reference electrode” includes both a) reference electrodes and b) reference electrodes that also function as counter electrodes (i.e., counter/reference electrodes), unless otherwise indicated.
[0042] The term “counter electrode” includes both a) counter electrodes and b) counter electrodes that also function as reference electrodes (i.e., counter/reference electrodes), unless otherwise indicated.
[0043] In general, membrane of the present invention is formed by crosslinking a modified polymer containing heterocyclic nitrogen groups in an alcohol-buffer mixed solvent and allowing the membrane solution to cure over time. The polymer comprises poly(heterocyclic nitrogen-containing constituent) as a portion of its backbone and additional elements, including a zwitterionic moiety, a hydrophobic moiety, and optionally, a biocompatible moiety. The resulting membrane is capable of limiting the flux of an analyte from one space, such as a space associated with a biofluid, to another space, such as space associated with an enzyme-containing sensing layer. An amperometric glucose sensor constructed of a wired-enzyme sensing layer and a glucose-diffusion-limiting layer of the present invention is very stable and has a large linear detection range.
Heterocyclic-Nitrogen Containing Polymers
[0044] The polymer of the present invention has the following general formula, Formula 1a:
[0000]
[0000] wherein the horizontal line represents a polymer backbone; A is an alkyl group substituted with a water soluble group, preferably a negatively charged group, such as sulfonate, phosphate, or carboxylate, and more preferably, a strong acid group such as sulfonate, so that the quaternized heterocyclic nitrogen to which it is attached is zwitterionic; D is a copolymer component of the polymer, as further described below; each of n, l, and p is independently an average number of an associated polymer unit or polymer units shown in the closest parentheses to the left; and q is a number of a polymer unit or polymer units shown in the brackets.
[0045] The heterocyclic nitrogen groups of Formula 1a include, but are not limited to, pyridine, imidazole, oxazole, thiazole, pyrazole, or any derivative thereof. Preferably, the heterocyclic nitrogen groups are independently vinylpyridine, such as 2-, 3-, or 4-vinylpyridine, or vinylimidazole, such as 1-, 2-, or 4-vinylimidazole. More preferably, the heterocyclic nitrogen groups are independently 4-vinylpyridine, such that the more preferable polymer is a derivative of poly(4-vinylpyridine). An example of such a poly(4-vinylpyridine) of the present invention has the following general formula, Formula 1b:
[0000]
[0000] wherein A, D, n, l, p and q are as described above in relation to Formula 1a.
[0046] While the polymer of the present invention has the general Formula 1a or Formula 1b above, it should be noted that when A is a strong acid, such as a stronger acid than carboxylic acid, the D component is optional, such that p may equal zero. Such a polymer of the present invention has the following general formula, Formula 1c:
[0000]
[0000] wherein A is a strong acid and the heterocyclic nitrogen groups, n, l and q are all as described above. Sulfonate and fluorinated carboxylic acid are examples of suitably strong acids. It is believed that when A is a sufficiently strong acid, the heterocyclic nitrogen to which it is attached becomes zwitterionic and thus capable of forming intermolecular electrostatic bonds with the crosslinker during membrane formation. It is believed that these intermolecular electrostatic bonds provide another level of crosslinking, beyond the covalent bonds typical of crosslinking, and thus make the resulting membrane stronger. As a result, when A is a suitably strong acid, the D component, which is often a strengthening component such as styrene, may be omitted from the polymers of Formulas 1a and 1b above. When A is a weaker acid, such that the heterocyclic nitrogen is not zwitterionic or capable of forming intermolecular electrostatic bonds, the polymer of the present invention does include D, as shown in Formulas 1a and 1b above.
[0047] Examples of A include, but are not limited to, sulfopropyl, sulfobutyl, carboxypropyl, and carboxypentyl. In one embodiment of the invention, group A has the formula -L-G, where L is a C2-C12 linear or branched alkyl linker optionally and independently substituted with an aryl, alkoxy, alkenyl, alkynyl, —F, —Cl, —OH, aldehyde, ketone, ester, or amide group, and G is a negatively charged carboxy or sulfonate group. The alkyl portion of the substituents of L have 1-6 carbons and are preferably an aryl, —OH or amide group.
[0048] A can be attached to the heterocyclic nitrogen group via quaternization with an alkylating agent that contains a suitable linker L and a negatively charged group G, or a precursor group that can be converted to a negatively charged group G at a later stage. Examples of suitable alkylating agents include, but are not limited to, 2-bromoethanesulfonate, propanesultone, butanesultone, bromoacetic acid, 4-bromobutyric acid and 6-bromohexanoic acid. Examples of alkylating agents containing a precursor group include, but are not limited to, ethyl bromoacetate and methyl 6-bromohexanoate. The ethyl and methyl ester groups of these precursors can be readily converted to a negatively charged carboxy group by standard hydrolysis.
[0049] Alternatively, A can be attached to the heterocyclic nitrogen group by quaternizing the nitrogen with an alkylating agent that contains an additional reactive group, and subsequently coupling, via standard methods, this additional reactive group to another molecule that contains a negatively charged group G and a reactive group. Typically, one of the reactive groups is an electrophile and the other reactive group is a nucleophile. Selected examples of reactive groups and the linkages formed from their interactions are shown in Table 1.
[0000] TABLE 1 Examples of Reactive Groups and Resulting Linkages First Reactive Group Second Reactive Group Resulting Linkage Activated ester* Amine Amide Acrylamide Thiol Thioether Acyl azide Amine Amide Acyl halide Amine Amide Carboxylic acid Amine Amide Aldehyde or ketone Hydrazine Hydrazone Aldehyde or ketone Hydroxyamine Oxime Alkyl halide Amine Alkylamine Alkyl halide Carboxylic acid Ester Alkyl halide Imidazole Imidazolium Alkyl halide Pyridine Pyridinium Alkyl halide Alcohol/phenol Ether Alkyl halide Thiol Thioether Alkyl sulfonate Thiol Thioether Alkyl sulfonate Pyridine Pyridinium Alkyl sulfonate Imidazole Imidazolium Alkyl sulfonate Alcohol/phenol Ether Anhydride Alcohol/phenol Ester Anhydride Amine Amide Aziridine Thiol Thioether Aziridine Amine Alkylamine Aziridine Pyridine Pyridinium Epoxide Thiol Thioether Epoxide Amine Alkylamine Epoxide Pyridine Pyridinium Halotriazine Amine Aminotriazine Halotriazine Alcohol Triazinyl ether Imido ester Amine Amidine Isocyanate Amine Urea Isocyanate Alcohol Urethane Isothiocyanate Amine Thiourea Maleimide Thiol Thioether Sulfonyl halide Amine Sulfonamide *Activated esters, as understood in the art, generally include esters of succinimidyl, benzotriazolyl, or aryl substituted by electron-withdrawing groups such as sulfo, nitro, cyano, or halo; or carboxylic acids activated by carbodiimides.
By way of example, A may be attached to the heterocyclic nitrogen groups of the polymer by quaternizing the heterocyclic nitrogens with 6-bromohexanoic acid and subsequently coupling the carboxy group to the amine group of 3-amino-1-propanesulfonic acid in the presence of a carbodiimide coupling agent.
[0050] D is a component of a poly(heterocyclic nitrogen-co-D) polymer of Formula 1a or 1b. Examples of D include, but are not limited to, phenylalkyl, alkoxystyrene, hydroxyalkyl, alkoxyalkyl, alkoxycarbonylalkyl, and a molecule containing a poly(ethylene glycol) or polyhydroxyl group. Some poly(heterocyclic nitrogen-co-D) polymers suitable starting materials for the present invention are commercially available. For example, poly(2-vinylpyridine-co-styrene), poly(4-vinylpyridine-co-styrene) and poly(4-vinylpyridine-co-butyl methacrylate) are available from Aldrich Chemical Company, Inc. Other poly(heterocyclic nitrogen-co-D) polymers can be readily synthesized by anyone skilled in the art of polymer chemistry using well-known methods. Preferably, D is a styrene or a C1-C18 alkyl methacrylate component of a polyvinylpyridine-poly-D, such as (4-vinylpyrine-co-styrene) or poly(4-vinylpyridine-co-butyl methacrylate), more preferably, the former. D may contribute to various desirable properties of the membrane including, but not limited to, hydrophobicity, hydrophilicity, solubility, biocompatibility, elasticity and strength. D may be selected to optimize or “fine-tune” a membrane made from the polymer in terms of its permeability to an analyte and its non-permeability to an undesirable, interfering component, for example.
[0051] The letters n, l, and p designate, respectively, an average number of each copolymer component in each polymer unit. The letter q is one for a block copolymer or a number greater than one for a copolymer with a number of repeating polymer units. By way of example, the q value for a polymer of the present invention may be ≧about 950, where n, l and p are 1, 8 and 1, respectively. The letter q is thus related to the overall molecular weight of the polymer. Preferably, the average molecular weight of the polymer is above about 50,000, more preferably above about 200,000, most preferably above about 1,000,000.
[0052] The polymer of the present invention may comprise a further, optional copolymer, as shown in the following general formula, Formula 2a:
[0000]
[0000] wherein the polymer backbone, A, D, n, l, p and q are as described above in relation to Formulas 1a-1c; m is an average number of an associated polymer unit or polymer units shown in the closest parentheses to the left; and B is a modifier. When the heterocyclic nitrogen groups are 4-substituted pyridine, as is preferred, the polymer of the present invention is derivative of poly(4-vinylpyridine) and has the general formula, Formula 2b, set forth below.
[0000]
[0000] Further, when A is a suitably strong acid, as described above, the D copolymer is optional, in which case the polymer of the present invention has the general formula, Formula 2c:
[0000]
[0053] In any of Formulas 2a-2c, B is a modifier group that may add any desired chemical, physical or biological properties to the membrane. Such desired properties include analyte selectivity, hydrophobicity, hydrophilicity, elasticity, and biocompatibility. Examples of modifiers include the following: negatively charged molecules that may minimize entrance of negatively charged, interfering chemicals into the membrane; hydrophobic hydrocarbon molecules that may increase adhesion between the membrane and sensor substrate material; hydrophilic hydroxyl or polyhydroxy molecules that may help hydrate and add biocompatibility to the membrane; silicon polymers that may add elasticity and other properties to the membrane; and poly(ethylene glycol) constituents that are known to increase biocompatibility of biomaterials (Bergstrom, K., et al., J. Biomed. Mat. Res. 26, 779 (1992)). Further examples of B include, but are not limited to, a metal chelator, such as a calcium chelator, and other biocompatible materials. A poly(ethylene glycol) suitable for biocompatibility modification of the membrane generally has a molecular weight of from about 100 to about 20,000, preferably, from about 500 to about 10,000, and more preferably, from about 1,000 to about 8,000.
[0054] The modifier B can be attached to the heterocyclic nitrogens of the polymer directly or indirectly. In direct attachment, the heterocyclic nitrogen groups may be reacted with a modifier containing an alkylating group. Suitable alkylating groups include, but are not limited to, alkyl halide, epoxide, aziridine, and sulfonate esters. In indirect attachment, the heterocyclic nigrogens of the polymer may be quaternized with an alkylating agent having an additional reactive group, and then attached to a molecule having a desired property and a suitable reactive group.
[0055] As described above, the B-containing copolymer is optional in the membrane of the present invention, such that when m of Formula 2a-2c is zero, the membrane has the general formula of Formula 1a-1c, respectively. The relative amounts of the four copolymer components, the heterocyclic nitrogen group containing A, the optional heterocyclic nitrogen group containing B, the heterocyclic nitrogen group, and D, may be expressed as percentages, as follows: [n/(n+m+l+p)]×100%, [m/(n+m+l+p)]×100%, [l/(n+m+l+p)]×100%, and [p/(n+m+l+p)]×100%, respectively. Suitable percentages are 1-25%, 0-15% (when the B-containing heterocyclic nitrogen group is optional) or 1-15%, 20-90%, and 0-50% (when D is optional) or 1-50%, respectively, and preferable percentages are 5-20%, 0-10% (when the B-containing heterocyclic nitrogen group is optional) or 1-10%, 60-90%, and 5-20%, respectively.
[0056] Specific examples of suitable polymers have the general formulas, Formulas 3-6, shown below.
[0000]
Examples of Syntheses of Polyvinylpyridine Polymers
[0057] Examples showing the syntheses of various polyvinylpyridine polymers according to the present invention are provided below. Numerical figures provided are approximate.
Example 1
Synthesis of a Polymer of Formula 3
[0058] By way of illustration, an example of the synthesis of a polymer of Formula 3 above, is now provided. A solution of poly(4-vinylpyridine-co-styrene) (˜10% styrene content) (20 g, Aldrich) in 100 mL of dimethyl formamide (DMF) at 90° C. was stirred and 6-bromohexanoic acid (3.7 g) in 15-20 mL of DMF was added. The resulting solution was stirred at 90° C. for 24 hours and then poured into 1.5 L of ether, whereupon the solvent was decanted. The remaining, gummy solid was dissolved in MeOH (150-200 mL) and suction-filtered through a medium-pore, fritted funnel to remove any undissolved solid. The filtrate was added slowly to rapidly stirred ether (1.5 L) in a beaker. The resulting precipitate was collected by suction filtration and dried at 50° C. under high vacuum for 2 days. The polymer had the following parameters: [n/(n+l+p)]×100%≈10%; [l/(n++l+p)]×100%≈80%; and [p/(n+l+p)]×100%≈10%.
Example 2
Synthesis of a Polymer of Formula 5
[0059] By way of illustration, an example of the synthesis of a polymer of Formula 5 above, is now provided. A solution of poly(4-vinylpyridine-co-styrene) (˜10% styrene) (20 g, Aldrich) in 100 mL of anhydrous DMF at 90° C. was stirred, methanesulfonic acid (˜80 mg) was added, and then 2 g of methoxy-PEG-epoxide (molecular weight 5,000) (Shearwater Polymers, Inc.) in 15-20 mL of anhydrous DMF was added. The solution was stirred at 90° C. for 24 hours and 1,3-Propane sultone (2.32 g) in 10 mL of anhydrous DMF was added. The resulting solution was continuously stirred at 90° for 24 hours, and then cooled to room temperature and poured into 800 mL of ether. The solvent was decanted and the remaining precipitate was dissolved in hot MeOH (˜200 mL), suction-filtered, precipitated again from 1 L of ether, and then dried at 50° C. under high vacuum for 48 hours. The resulting polymer has the following parameters: [n/(n+m+l+p)]×100%≈10%; [m/(n+m+l+p)]×100%≈10%; [l/(n+m+l+p)]×100%≈70%; and [p/(n+m+l+p)]×100%≈10%.
Example 3
Synthesis of a Polymer Having a Polyhydroxy Modifier B
[0060] By way of illustration, an example of the synthesis of a polymer having a polyhydroxy modifier B, as schematically illustrated below, is now provided. Various polyhydroxy compounds are known for having biocompatibility properties. (U.S. Pat. No. 6,011,077.) The synthesis below illustrates how a modifier group having a desired property may be attached to the polymer backbone via a linker.
[0000]
[0000] 1,3-propane sultone (0.58 g, 4.8 mmoles) and 6-bromohexanoic acid (1.85 g, 9.5 mmoles) are added to a solution of poly(4-vinylpyridine-co-styrene) (˜10% styrene) (10 g) dissolved in 60 mL of anhydrous DMF. The resulting solution is stirred at 90° C. for 24 hours and then cooled to room temperature. O—(N-succinimidyl)-N,N,N′,N′-tetramethyl-uronium tetrafluoroborate (TSTU) (2.86 g, 9.5 mmoles) and N,N-diisopropylethylamine (1.65 mL, 9.5 mmoles) are then added in succession to the solution. After the solution is stirred for 5 hours, N-methyl-D-glucamine (2.4 g, 12.4 mmoles) is added and the resulting solution is stirred at room temperature for 24 hours. The solution is poured into 500 ml of ether and the precipitate is collected by suction filtration. The collected precipitate is then dissolved in MeOH/H 2 O and the resulting solution is subjected to ultra membrane filtration using the same MeOH/H 2 O solvent to remove small molecules. The dialyzed solution is evaporated to dryness to give a polymer with the following parameters: [n/(n+m+l+p)]×100%≈10%; [m/(n+m+l+p)]×100%≈10%; [l/(n+m+l+p)]×100%≈70%; and [p/(n+m+l+p)]×100≈10%.
Crosslinkers
[0061] Crosslinkers of the present invention are molecules having at least two reactive groups, such as bi-, tri-, or tetra-functional groups, capable of reacting with the heterocyclic nitrogen groups, pyridine groups, or other reactive groups contained on A, B or D of the polymer. Preferably, the reactive groups of the crosslinkers are slow-reacting alkylating groups that can quaternize the heterocyclic nitrogen groups, such as pyridine groups, of the polymer. Suitable alkylating groups include, but are not limited to, derivatives of poly(ethylene glycol) or poly(propylene glycol), epoxide (glycidyl group), aziridine, alkyl halide, and sulfonate esters. Alkylating groups of the crosslinkers are preferably glycidyl groups. Preferably, glycidyl crosslinkers have a molecular weight of from about 200 to about 2,000 and are water soluble or soluble in a water-miscible solvent, such as an alcohol. Examples of suitable crosslinkers include, but are not limited to, poly(ethylene glycol) diglycidyl ether with a molecular weight of about 200 to about 600, and N,N-diglycidyl-4-glycidyloxyaniline.
[0062] It is desirable to have a slow crosslinking reaction during the dispensing of membrane solution so that the membrane coating solution has a reasonable pot-life for large-scale manufacture. A fast crosslinking reaction results in a coating solution of rapidly changing viscosity, which renders coating difficult. Ideally, the crosslinking reaction is slow during the dispensing of the membrane solution, and accelerated during the curing of the membrane at ambient temperature, or at an elevated temperature where possible.
Membrane Formation and Sensor Fabrication
[0063] An example of a process for producing a membrane of the present invention is now described. In this example, the polymer of the present invention and a suitable crosslinker are dissolved in a buffer-containing solvent, typically a buffer-alcohol mixed solvent, to produce a membrane solution. Preferably, the buffer has a pH of about 7.5 to about 9.5 and the alcohol is ethanol. More preferably, the buffer is a 10 mM (2-(4-(2-hydroxyethyl)-1-piperazine)ethanesulfonate) (HEPES) buffer (pH 8) and the ethanol to buffer volume ratio is from about 95 to 5 to about 0 to 100. A minimum amount of buffer is necessary for the crosslinking chemistry, especially if an epoxide or aziridine crosslinker is used. The amount of solvent needed to dissolve the polymer and the crosslinker may vary depending on the nature of the polymer and the crosslinker. For example, a higher percentage of alcohol may be required to dissolve a relatively hydrophobic polymer and/or crosslinker.
[0064] The ratio of polymer to cross-linker is important to the nature of the final membrane. By way of example, if an inadequate amount of crosslinker or an extremely large excess of crosslinker is used, crosslinking is insufficient and the membrane is weak. Further, if a more than adequate amount of crosslinker is used, the membrane is overly crosslinked such that membrane is too brittle and/or impedes analyte diffusion. Thus, there is an optimal ratio of a given polymer to a given crosslinker that should be used to prepare a desirable or useful membrane. By way of example, the optimal polymer to crosslinker ratio by weight is typically from about 4:1 to about 32:1 for a polymer of any of Formulas 3-6 above and a poly(ethylene glycol) diglycidyl ether crosslinker, having a molecular weight of about 200 to about 400. Most preferably, this range is from about 8:1 to about 16:1. Further by way of example, the optimal polymer to crosslinker ratio by weight is typically about 16:1 for a polymer of Formula 4 above, wherein [n/(n+l+p)]×100%≈10%, [l/(n+l+p)]×100%≈80%, and [p/(n+l+p)]×100%≈, 10%, or for a polymer of Formula 5 above, wherein [n/(n+m+l+p)]×100%≈10%, [m/(n+m+l+p)]×100%≈10%, [l/(n+m+l+p)]×100%≈70%, [p/(n+m+l+p)]×100%≈10%, and r≈110, and a poly(ethylene glycol) diglycidyl ether crosslinker having a molecular weight of about 200.
[0065] The membrane solution can be coated over a variety of biosensors that may benefit from having a membrane disposed over the enzyme-containing sensing layer. Examples of such biosensors include, but are not limited to, glucose sensors and lactate sensors. (See U.S. Pat. No. 6,134,461 to Heller et al., which is incorporated herein in its entirety by this reference.) The coating process may comprise any commonly used technique, such as spin-coating, dip-coating, or dispensing droplets of the membrane solution over the sensing layers, and the like, followed by curing under ambient conditions typically for 1 to 2 days. The particular details of the coating process (such as dip duration, dip frequency, number of dips, or the like) may vary depending on the nature (i.e., viscosity, concentration, composition, or the like) of the polymer, the crosslinker, the membrane solution, the solvent, and the buffer, for example. Conventional equipment may be used for the coating process, such as a DSG D1L-160 dip-coating or casting system of NIMA Technology in the United Kingdom.
Example of Sensor Fabrication
[0066] Sensor fabrication typically consists of depositing an enzyme-containing sensing layer over a working electrode and casting the diffusion-limiting membrane layer over the sensing layer, and optionally, but preferably, also over the counter and reference electrodes. The procedure below concerns the fabrication of a two-electrode sensor, such as that depicted in FIGS. 2A-2C . Sensors having other configurations such as a three-electrode design can be prepared using similar methods.
[0067] A particular example of sensor fabrication, wherein the numerical figures are approximate, is now provided. A sensing layer solution was prepared from a 7.5 mM HEPES solution (0.5 μL, pH 8), containing 1.7 μg of the polymeric osmium mediator compound L, as disclosed in Published Patent Cooperation Treaty (PCT) Application, International Publication No. WO 01/36660 A2, which is incorporated herein in its entirety by this reference; 2.1 μg of glucose oxidase (Toyobo); and 1.3 μg of poly(ethylene glycol) diglycidyl ether (molecular weight 400). Compound L is shown below.
[0000]
[0000] The sensing layer solution was deposited over carbon-ink working electrodes and cured at room temperature for two days to produce a number of sensors. A membrane solution was prepared by mixing 4 volumes of a polymer of Formula 4 above, dissolved at 64 mg/mL in 80% EtOH/20% HEPES buffer (10 mM, pH 8), and one volume of poly(ethylene glycol) diglycidyl ether (molecular weight 200), dissolved at 4 mg/mL in 80% EtOH/20% HEPES buffer (10 mM, pH 8). The above-described sensors were dipped three times into the membrane solution, at about 5 seconds per dipping, with about a 10-minute time interval between consecutive dippings. The sensors were then cured at room temperature and normal humidity for 24 hours.
[0068] An approximate chemical structure of a section of a typical membrane prepared according to the present invention is shown in FIG. 1 . Such a membrane may be employed in a variety of sensors, such as the two- or three-electrode sensors described previously herein. By way of example, the membrane may be used in a two-electrode amperometric glucose sensor, as shown in FIG. 2A-2C (collectively FIG. 2 ) and described below.
[0069] The amperometric glucose sensor 10 of FIG. 2 comprises a substrate 12 disposed between a working electrode 14 that is typically carbon-based, and a Ag/AgCl counter/reference electrode 16 . A sensor or sensing layer 18 is disposed on the working electrode. A membrane or membrane layer 20 encapsulates the entire glucose sensor 10 , including the Ag/AgCl counter/reference electrode.
[0070] The sensing layer 18 of the glucose sensor 10 consists of crosslinked glucose oxidase and a low potential polymeric osmium complex mediator, as disclosed in the above-mentioned Published PCT Application, International Publication No. WO 01/36660 A2. The enzyme- and mediator-containing formulation that can be used in the sensing layer, and methods for applying them to an electrode system, are known in the art, for example, from U.S. Pat. No. 6,134,461. According to the present invention, the membrane overcoat was formed by thrice dipping the sensor into a membrane solution comprising 4 mg/mL poly(ethylene glycol) diglycidyl ether (molecular weight of about 200) and 64 mg/mL of a polymer of Formula 4 above, wherein [n/(n+l+p)]×100%≈10%; [l/(n+l+p)]×100%≈80%; and [p/(n+l+p)]×100%≈10%, and curing the thrice-dipped sensor at ambient temperature and normal humidity for at least 24 hours, such as for about 1 to 2 days. The q value for such a membrane overcoat may be ≧about 950, where n, l and p are 1, 8 and 1, respectively.
Membrane Surface Modification
[0071] Polymers of the present invention have a large number of heterocyclic nitrogen groups, such as pyridine groups, only a few percent of which are used in crosslinking during membrane formation. The membrane thus has an excess of these groups present both within the membrane matrix and on the membrane surface. Optionally, the membrane can be further modified by placing another layer of material over the heterocyclic-nitrogen-group-rich or pyridine-rich membrane surface. For example, the membrane surface may be modified by adding a layer of poly(ethylene glycol) for enhanced biocompatibility. In general, modification may consist of coating the membrane surface with a modifying solution, such as a solution comprising desired molecules having an alkylating reactive group, and then washing the coating solution with a suitable solvent to remove excess molecules. This modification should result in a monolayer of desired molecules.
[0072] The membrane 20 of the glucose sensor 10 shown in FIG. 2 may be modified in the manner described above.
Experimental Examples
[0073] Examples of experiments that demonstrate the properties and/or the efficacy of sensors having diffusion-limiting membranes according to the present invention are provided below. Numerical figures provided are approximate.
Calibration Experiment
[0074] In a first example, a calibration experiment was conducted in which fifteen sensors lacking membranes were tested simultaneously (Set 1), and separately, eight sensors having diffusion-limiting membranes according to the present invention were tested simultaneously (Set 2), all at 37° C. In Set 2, the membranes were prepared from polymers of Formula 4 above and poly(ethylene glycol) diglycidyl ether (PEGDGE) crosslinkers, having a molecular weight of about 200. In the calibration experiment for each of Set 1 and Set 2, the sensors were placed in a PBS-buffered solution (pH 7) and the output current of each of the sensors was measured as the glucose concentration was increased. The measured output currents (μA for Set 1; nA for Set 2) were then averaged for each of Set 1 and Set 2 and plotted against glucose concentration (mM), as shown in the calibration graph of FIG. 3 .
[0075] As shown, the calibration curve for the Set 1 sensors lacking membranes is approximately linear over a very small range of glucose concentrations, from zero to about 3 mM, or 5 mM at most. This result indicates that the membrane-free sensors are insufficiently sensitive to glucose concentration change at elevated glucose concentrations such as 10 mM, which is well below the high end of clinically relevant glucose concentration at about 30 mM. By contrast, the calibration curve for the Set 2 sensors having diffusion-limiting membranes according to the present invention is substantially linear over a relatively large range of glucose concentrations, for example, from zero to about 30 mM, as demonstrated by the best-fit line (y=1.2502x+1.1951; R 2 ≈0.997) also shown in FIG. 3 . This result demonstrates the considerable sensitivity of the membrane-equipped membranes to glucose concentration, at low, medium, and high glucose concentrations, and of particular relevance, at the high end of clinically relevant glucose concentration at about 30 mM.
Stability Experiment
[0076] In a second example, a stability experiment was conducted in which a sensor lacking a membrane and a sensor having a diffusion-limiting membrane according to the present invention were tested, simultaneously, at 37° C. The membrane-equipped sensor had a membrane prepared from the same polymer and the same crosslinker as those of the sensors of Set 2 described above in the calibration experiment. In this stability experiment, each of the sensors was placed in a PBS-buffered solution (pH 7) having a fixed glucose concentration of 30 mM, and the output current of each of the sensors was measured. The measured output currents (μA for the membrane-less sensor; nA for the membrane-equipped sensor) were plotted against time (hour), as shown in the stability graph of FIG. 4 .
[0077] As shown, the stability curve for the membrane-less sensor decays rapidly over time, at a decay rate of about 4.69% μA per hour. This result indicates a lack of stability in the membrane-less sensor. By contrast, the stability curve for the membrane-equipped sensor according to the present invention shows relative constancy over time, or no appreciable decay over time, the decay rate being only about 0.06% nA per hour. This result demonstrates the considerable stability and reliability of the membrane-equipped sensors of the present invention. That is, at a glucose concentration of 30 mM, while the membrane-less sensor lost sensitivity at a rate of almost 5% per hour over a period of about 20 hours, the membrane-equipped sensor according to the present invention showed virtually no loss of sensitivity over the same period.
Responsivity Experiment
[0078] Ideally, the membrane of an electrochemical sensor should not impede communication between the sensing layer of the sensor and fluid or biofluid containing the analyte of interest. That is, the membrane should respond rapidly to changes in analyte concentration.
[0079] In a third example, a responsivity experiment was conducted in which eight sensors having diffusion-limiting membranes according to the present invention were tested simultaneously (Set 3), all at 37° C. The sensors of Set 3 had membranes prepared from the same polymers and the same crosslinkers as those of the sensors of Set 2 described in the calibration experiment above. In this responsivity experiment, the eight sensors were placed in a PBS-buffered solution (pH 7), the glucose concentration of which was increased in a step-wise manner over time, as illustrated by the glucose concentrations shown in FIG. 5 , and the output current of each of the sensors was measured. The measured output currents (nA) were then averaged for Set 3 and plotted against time (real time, hour:minute:second), as shown in the responsivity graph of FIG. 5 .
[0080] The responsivity curve for the Set 3 sensors having diffusion-limiting membranes according to the present invention has discrete steps that mimic the step-wise increases in glucose concentration in a rapid fashion. As shown, the output current jumps rapidly from one plateau to the next after the glucose concentration is increased. This result demonstrates the considerable responsivity of the membrane-equipped sensors of the present invention. The responsivity of these membrane-equipped electrochemical sensors makes them ideal for analyte sensing, such as glucose sensing.
Motion-Sensitivity Experiment
[0081] Ideally, the membrane of an electrochemical sensor should be unaffected by motion or movement of fluid or biofluid containing the analyte of interest. This is particularly important for a sensor that is implanted in a body, such as a human body, as body movement may cause motion-associated noise and may well be quite frequent.
[0082] In this fourth example, a motion-sensitivity experiment was conducted in which a sensor A lacking a membrane was tested, and separately, a sensor B having a diffusion-limiting membrane according to the present invention was tested, all at 37° C. Sensor B had a membrane prepared from the same polymer and the same crosslinker as those of the sensors of Set 2 described in the calibration experiment above. In this experiment, for each of test, the sensor was placed in a beaker containing a PBS-buffered solution (pH 7) and a magnetic stirrer. The glucose concentration of the solution was increased in a step-wise manner over time, in much the same manner as described in the responsivity experiment above, as indicated by the various mM labels in FIG. 6 . The stirrer was activated during each step-wise increase in the glucose concentration and deactivated some time thereafter, as illustrated by the “stir on” and “stir off” labels shown in FIG. 6 . This activation and deactivation of the stirrer was repeated in a cyclical manner at several levels of glucose concentration and the output current of each of the sensors was measured throughout the experiment. The measured output currents (μA for sensor A; nA for sensor B) were plotted against time (minute), as shown in the motion-sensitivity graph of FIG. 6 .
[0083] As shown, the output current for the membrane-less sensor A is greatly affected by the stir versus no stir conditions over the glucose concentration range used in the experiment. By contrast, the output current for sensor B, having diffusion-limiting membranes according to the present invention, is virtually unaffected by the stir versus no stir conditions up to a glucose concentration of about 10 mM, and only slightly affected by these conditions at a glucose concentration of about 15 mM. This result demonstrates the considerable stability of the membrane-equipped sensors of the present invention in both stirred and non-stirred environments. The stability of these membrane-equipped electrochemical sensors in an environment of fluid movement makes them ideal for analyte sensing within a moving body.
Sensor Reproducibility Experiment
[0084] Dip-coating, or casting, of membranes is typically carried out using dipping machines, such as a DSG D1L-160 of NIMA Technology of the United Kingdom. Reproducible casting of membranes has been considered quite difficult to achieve. (Chen, T., et al., In Situ Assembled Mass - Transport Controlling Micromembranes and Their Application in Implanted Amperometric Glucose Sensors , Anal. Chem., Vol. 72, No. 16, Pp. 3757-3763 (2000).) Surprisingly, sensors of the present invention can be made quite reproducibly, as demonstrated in the experiment now described.
[0085] Four batches of sensors (Batches 1-4) were prepared separately according to the present invention, by dipping the sensors in membrane solution three times using casting equipment and allowing them to cure. In each of the four batches, the membrane solutions were prepared from the polymer of Formula 4 and poly(ethylene glycol) digycidyl ether (PEDGE) crosslinker having a molecular weight of about 200 (as in Set 2 and other Sets described above) using the same procedure. The membrane solutions for Batches 1 and 2 were prepared separately from each other, and from the membrane solution used for Batches 3 and 4. The membrane solution for Batches 3 and 4 was the same, although the Batch 3 and Batch 4 sensors were dip-coated at different times using different casting equipment. That is, Batches 1, 2 and 3 were dip-coated using a non-commercial, built system and Batch 4 was dip-coated using the above-referenced DSG D1L-160 system.
[0086] Calibration tests were conducted on each batch of sensors at 37° C. For each batch, the sensors were placed in PBS-buffered solution (pH 7) and the output current (nA) of each of the sensors was measured as the glucose concentration (mM) was increased. For each sensor in each of the four batches, a calibration curve based on a plot of the current output versus glucose concentration was prepared as shown in FIG. 7B (Batch 1: 5 sensors), FIG. 7C (Batch 2: 8 sensors), FIG. 7D (Batch 3: 4 sensors) and FIG. 7E (Batch 4: 4 sensors). The average slopes of the calibration curves for each batch were the following:
Batch 1: Average Slope=1.10 nA/mM (CV=5%); Batch 2: Average Slope=1.27 nA/mM (CV=10%); Batch 3: Average Slope=1.15 nA/mM (CV=5%); and Batch 4: Average Slope=1.14 nA/mM (CV=7%).
Further, for each batch, the current output for the sensors in the batch was averaged and plotted against glucose concentration, as shown in FIG. 7A . The average slope for Batches 1-4 was 1.17 nA/mM (CV=7.2%).
[0091] The slopes of the curves within each batch and from batch-to-batch are very tightly grouped, showing considerably little variation. The results demonstrate that sensors prepared according to the present invention give quite reproducible results, both within a batch and from batch-to-batch.
[0092] The foregoing examples demonstrate many of the advantages of the membranes of the present invention and the sensors employing such membranes. Particular advantages of sensors employing the membranes of the present invention include sensitivity, stability, responsivity, motion-compatibility, ease of calibration, and ease and reproducibility of manufacture.
[0093] Various aspects and features of the present invention have been explained or described in relation to beliefs or theories, although it will be understood that the invention is not bound to any particular belief or theory. Various modifications, processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the specification. Although the various aspects and features of the present invention have been described with respect to various embodiments and specific examples herein, it will be understood that the invention is entitled to protection within the full scope of the appended claims.
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Novel membranes comprising various polymers containing heterocyclic nitrogen groups are described. These membranes are usefully employed in electrochemical sensors, such as amperometric biosensors. More particularly, these membranes effectively regulate a flux of analyte to a measurement electrode in an electrochemical sensor, thereby improving the functioning of the electrochemical sensor over a significant range of analyte concentrations. Electrochemical sensors equipped with such membranes are also described.
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This invention relates to solar electric power generators and in particular to controllers for such generators.
BACKGROUND OF THE INVENTION
Solar electric generators (SG's) have been commercially available in the United States for about 25 years. These units generate electric power from the energy of sunlight, which is free. Attempts have been made to produce electric power from sunlight to supply utility electric grids but these efforts have been largely unsuccessful because the total cost per kilowatt-hour from the solar generators substantially exceed the cost per kilowatt hour for electric power generated at central generating stations powered by burning coal, oil, gas or by nuclear power plants.
The RV Market
However, when it is not feasible to hook up to a power grid fed by a central generating station, the solar electric generator is often the power source of choice. Competitive power sources include gasoline powered motor generating units and thermoelectric devices generating electric power based on the thermoelectric effect from a temperature difference. A very lucrative market for solar generators is to provide electric power for recreation vehicles (RV's) when the engine of the vehicle is not being utilized for travel. In this situation, the solar unit provides electric power (considering all applicable cost including depreciation maintenance, etc.) at a small fraction of the cost of operation the vehicle gasoline engine to charge the battery or batteries of the RV. The typical RV has one or two batteries. When there are two batteries, one is for the engine and one is for the "house" portion of the RV. A controller is needed to control the supply of electricity to the batteries.
Prior art controllers have typically been rather simple devices and not much effort has gone into utilizing controllers to maximize the efficiency of solar power generators. Perhaps, the thinking has been "why worry about efficiency when the energy (from the sun) is free?"
The typical prior art solar generating unit sold for RV units is designed to produce power at about 17 volts for charging 12-volt batteries. The typical control unit comprises control switches (either relay control switches or solid state control switches) for connecting the output of the solar generator to the battery and a control unit which monitors the battery voltage and opens the switch when the battery voltage reaches a high target voltage, such as 14 volts and closes the switch when the respective battery voltage drops to a low target voltage such as 13 volts. The prior art control units are also typically constructed with a series diode to assure that current does not flow in reverse through the solar generator discharging the battery at night.
Constant Current Generators
Most solar generating units are designed to operate in what is called constant current mode. This means that for a given level of solar radiation such as 1000 W/m 2 , a substantially constant current is produced for any battery voltage within the design range of the solar generating unit. For example, FIG. 1 shows current vs. voltage for a typical solar unit, which is the BP275 Module available from BP Solar with offices in Fairfield, Calif. This graph shows that in the sunshine of 1000 W/m 2 at a solar generator temperature of about 25° C., the current produced by this unit is about 4.7 amps for battery voltages between 0 and 14 volts. The current drops off slightly to about 4.5 amps at 17 volts and drops to substantially zero at 21.4 volts. This is referred to as the open circuit voltage. Power is the product of current and voltage. Thus, if the battery being charged is at a low voltage level the rate of power delivery, and hence charging, can be substantially reduced.
What is needed is a better controller permitting the solar generating unit to function safely at or near its maximum power capacity.
SUMMARY OF THE INVENTION
The present invention provides a controller for a solar electric generator that permits the generator to produce power substantially at its maximum capacity. Power is transferred from the generator to a temporary electric storage device that is periodically partially drained of power to maintain the temporary electric storage device at a voltage corresponding to the voltage needed by the generator to provide maximum generator power. The electric power drained from the temporary storage device is used to charge conventional batteries. In a preferred embodiment, the temporary storage device is a capacitor that is part of a buck regulator operating at 50 kHz with duty factor control between 0% and 100%. This buck topology switching type regulator provides the periodic draining. In the preferred embodiment control of the duty factor of the buck regulator is utilized to limit current, to prevent battery over charging, to test for the voltage corresponding to maximum power, and to operate the solar generator at is maximum power voltage. When operated at its maximum power operating point, the output to the battery is constant power, providing greater battery charge current than prior art controllers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an estimated Voltage-Current curve for BP275 Modules at 25° C.
FIG. 1A shows an estimated Voltage-Power curve for BP275 Modules .
FIG. 2 shows a simplified functional drawing of a preferred embodiment of the present invention.
FIG. 3 shows an estimated Voltage-Current curve demonstrating array efficiency as a function of temperature for BP275 Modules at 1000 W/m 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
First Preferred Embodiment
A first preferred embodiment of the present invention is described in FIG. 2. This unit is designed to extract the maximum energy from a solar generating unit (such as the BP275 solar generator) which can be used for providing solar power for RV vehicles.
The data displayed in FIG. 1 was used to plot the curves in FIG. 1A. FIG. 1A reveals that (at 1,000 W/m 2 and 25° C.) the unit provides the maximum power at about 17 volts. At 17 volts, 1,000 W/m 2 and 25° C., the power (which is the product of current and voltage) is about 75 watts. (In terms of energy production this would be 75 watt-hours/hour). However, at 10 volts the power production is only 40 watts and at 20 volts the power production is also only 40 watts. FIG. 1A also shows the power vs. voltage curve for 500 and 250 W/m 2 .
The present invention recognizes the importance of operating the solar generating unit at its maximum power voltage (V MP ) which in this case (at 1000 W/m 2 and 25° C.) is about 17 volts. V MP does not vary very much with solar radiation levels, but varies significantly and predictably with array temperature.
As shown in FIG. 3 the open circuit voltage changes substantially with array temperature. However, the difference between SG open circuit voltage V OC and V MP is essentially constant regardless of array temperature. The actual operating point V MP is determined in this system by periodically sampling V OC , which changes with SG temperature, then subtracting the difference between a particular SG panel's datasheet values of V OC and V MP from the sampled V OC . The delta between V OC and V MP for the BP275 SG panel is approximately 4.4 volts. Applicant has determined that for the BP275 unit and similar units V MP is about 4.4 volts below the open circuit voltage at each radiation level over a wide range of levels from 1000 W/m 2 down to about 50 W/m 2 .
In many installations, several units like the BP275 are operated in parallel so that sufficient power can be generated under minimum radiation conditions. This means that when the sun is very bright, in summer at mid-day and with no clouds, the current generated may exceed the current carrying capacitance of the charging circuits. Applicant's controller deals with this issue.
Simplified Functional Drawing
FIG. 2 is a simplified functional drawing of this preferred embodiment of the present invention. A solar generator 2 comprising five parallel BP Solar Modules generates electric power for charging battery 3 from solar radiation 4 at voltages ranging from 0 to about 21.4 volts. Referring to FIG. 2, controller 1 includes a buck type switching voltage regulator 6 consisting primarily of a 43 μH inductor L1, a bucking capacitor C1, a field effect transistor Q1, a circulating diode CR1, a gate driver 8, a pulse width modulation controller 10 and a relay control switch 18. Within the basic buck regulator there are two current sensing resistors, R1 and R2, which measure solar generation (SG) current (input current to the buck regulator), and battery current (output current from the buck regulator) by means of differential amplifiers 12 and 14. The differential amplifiers produce voltages proportional to current through their respective resistor, which feed other circuit elements. One of the circuit elements fed by the differential amplifiers is a three and one-half digit voltmeter 16. This meter also reads battery voltage. Battery voltage is displayed to 10-millivolt resolution, whereas SG current and battery current are displayed to 100 milliamps resolution.
Whenever photons of sunshine illuminate the solar panels of solar electric generator array 2, each of the five panels of the generator will produce a quantity of electric current as indicated by FIG. 1. The total current is the sum of the current produced by each of the panels. The current produced is primarily dependent on the radiation level and the voltage on bucking regulator C1 and to a lesser degree, the temperature of the solar array.
In early morning when the sun begins to illuminate array 2, the array begins to charge bucking capacitor C1. Comparator 20 closes relay switch 18 when the I SG current reaches 110 milliamps and the voltage on capacitor C1 has reached 14 volts. Current source 97 has a saturation voltage of approximately 14 volts. Therefore, current will not flow until available voltage is approximately 14 volts. The voltage on bucking capacitor C1 determines the current flowing in circuit 22, in accordance with FIG. 2. As indicated above, a principal element of this invention is to assure maximum power transfer from a solar electric generator array 2 to bucking capacitor C1. This is in general accomplished by having Q1 operate at 50 kHz and at a duty cycle such that the voltage on C1 is maintained at a target voltage chosen to assure maximum power transfer from solar array 2 to bucking capacitor C1. Current is allowed by transistor Q1 to flow to battery 3 at a rate as necessary to assure that C1 remains at the proper target voltage. Inductor L1 limits the current flow at the beginning of each cycle of the duty cycle of transistor Q1 and serves as an energy storage unit in the buck regulator.
Once the charging system turns on, it remains enabled as long as SG current is greater than approximately 80 milliamps. This hysteresis of approximately 30 milliamps in turn on/off threshold assures that operation will be stable near the turn on/off transition range. If current through R1 drops below 80 milliamps, comparator 20 shuts the generator down.
The required SG current should be available at this relatively high voltage of 14 volts to assure that charge current will flow to the battery. If the on/off decision was based on short circuit current, partial shading of SG array 2 would produce sufficient current for the system to turn on under SG short circuit conditions, but current would not flow to the battery since partial shading would prevent the SG array from developing a sufficiently high voltage to overcome battery voltage, causing the charge control system to turn off. Under these conditions the charge on/off control system would be unstable.
At very low radiation levels, relay switch 18 is open, duty cycle is clamped to 0% preventing current flow to the battery. However, the small quantity of SG current generated is allowed to flow through an on/off controllable sinking current source 97. Current source 97 has a soft saturation voltage of approximately 14 volts and a current limit of approximately 140 milliamps. It is enabled whenever PWM duty cycle is less than approximately 20 percent and is disabled whenever PWM duty cycle is greater than approximately 20 percent. When the charge control system is off, the PWM duty cycle is clamped to 0%. At this point, current source 97 is on and it, in combination with R1, differential amplifier 12, and SG ON comparator 20, essentially search for sufficient SG voltage and current. If it is available, controller 1 turns on. Current source 97 also provides the function of maintaining a minimum SG current for controller 1 to remain on if duty cycle goes to 0% due to unusually high battery voltage, i.e. greater than setpoint. This assures that controller 1 will remain on whenever sufficient SG current and voltage are available regardless of PWM duty cycle. This also assures that current source 97 is turned off when the controller is delivering charge current to the battery and duty cycle is in the normal operating range of 50-100%.
Pulse Width Modulator Controller
The PWM control system of the switching regulator uses a PWM device that attempts to deliver 100 percent duty cycle at all times. It is configured in such a way that duty cycle can be limited by five separate controlling inputs. The analog OR'ing function is such that whichever of the five inputs is attempting to decrease PWM duty cycle, will override other inputs requesting greater duty cycle. The inputs that can reduce duty cycle are: 1) SG open circuit voltage sample pulse, 2) peak power SG voltage control, 3) SG ON comparator output low, 4) battery voltage control, and 5) output current limit.
(1) Open Circuit Measurement
As shown in FIG. 2, an approximation of the open circuit voltage of array 2 is measured every eight seconds by sample and hold circuit 22 based on a 15 ms signal from oscillator 24. PWM controller 10 reduces the duty cycle on Q1 transistor to zero for the 15 ms sample period to obtain the open circuit voltage approximation. During this 15 ms period the charge on C1 increases to approximately open circuit voltage and the voltage reading is stored by sample and hold circuit 22. After the 15 ms period, PWM controller 10 returns to normal operation.
(2) Peak Power Voltage Control
When SG voltage is sufficiently high, relative to battery voltage plus system voltage drops, such that 100% PWM duty cycle would produce an SG voltage below the maximum power voltage (V MP ), SG setpoint block 98 and SG servo block 99 reduce duty cycle such that SG voltage increases to V MP , and is servo controlled at this value.
The proper V MP setpoint is determined by SG setpoint block 98. SG setpoint block 98 has three inputs which are used to determine the V MP setpoint for the SG peak power voltage control SG servo 99. These inputs are; the sampled value of V OC as described above, a voltage proportional to SG current derived from resistor R1 and differential amplifier 12, and a user programmable voltage ΔV. ΔV is the difference between SG datasheet values of V OC and V MP and is substantially constant for the full expected SG temperature range as shown in FIG. 3. The user programs this value into the controller at the time of installation, which is 4.4V for the BP275 SG. The output of SG setpoint block 98 is equal to; ((sampled V OC )-ΔV - (0.07V/amp of SG current)). The 0.07V/amp of SG current correction factor decreases SG servo setpoint voltage to compensate for voltage drop in cabling between the controller and the SG. Due to cost, manageable wire size, etc., a typical installation will produce approximately a 0.7 volt drop at 10 amps between the SG and the controller terminals. Since the controller servos V MP at the controller terminals, actual SG voltage will typically be 0.7 volts higher than the desired SG voltage at the SG array terminals, at an SG current of 10 amps. This is also key to the invention as the correction factor eliminates the need for remote sensing of actual SG voltage.
The SG voltage setpoint feeds SG servo block 99, which controls the PWM duty cycle to maintain SG voltage at V MP . Note that the SG servo operates in a reverse polarity to a typical servo since lower SG voltage requires a decrease in duty cycle to raise SG voltage to the desired setpoint value.
Since under conditions of constant radiation and SG temperature the SG servo forces constant SG voltage at V MP regardless of battery voltage and current, the output operates as constant power due to the well understood characteristics of the traditional buck topology switching regulator. As battery voltage changes with constant SG input power, PWM duty cycle changes to maintain constant SG power. Since output power is essentially constant, a decrease in battery voltage produces an increase in charge current going to the battery. This application of buck topology power conversion technology is key to the invention.
But, whenever SG voltage is not sufficiently high, relative to battery voltage plus system voltage drops, such that a 100% PWM duty cycle produces a SG voltage above the maximum power voltage (V MP ), the SG servo saturates at 100% PWM duty cycle, and the system reverts to straight through direct connection to the battery the same as prior art. If the voltage becomes high enough, battery voltage servo limits and controls the voltage.
A key to proper sampling at low SG currents is the need to minimize the size of C1 so that zero SG current is flowing at the end of the sample pulse. In this application the United-Chemicon URZA series capacitor is used due to its very high ripple current capability at relatively low capacitance values. This unique capacitor allows proper V OC sampling, and therefore proper boost operation, at SG currents as low as 0.8 amps, while having a suitably high ripple current rating for long life in a 20 amp buck converter. Another key requirement to keeping the minimum SG current required for boost operation low is a large enough value of L1 relative of switching frequency to keep the buck converter in a continuous conduction operating mode. The combination of a 50 KHz operating frequency and 43 μH L1 inductor maintains continuous conduction under normal operating conditions down to an output current of approximately 0.9 amps. Therefore boost reliably operates down to an output current of just under 1.0 amp.
(3) SG Comparator Output Low
SG comparator 20, in addition to providing a signal to operate relay switch 18, provides a low current signal at 80 mA to initiate a zero duty cycle of buck regulator 6. This means that the controllable current source 97 should be on all the time whenever controller 1 is off.
(4) Battery Voltage Servo
In this preferred embodiment the duty factor is also subject to reduction based on battery high voltage. This high voltage setting is preferably set based on data provided by the battery manufacturer. A battery temperature signal from temperature sensor 26 is used by battery servo 28 to establish the high voltage limit which is used to direct PWM controller to reduce the duty factor as the limit is approached. In the preferred embodiment, an analog circuit is used to provide the temperature adjustment but a digital processor could also be utilized. For example, the voltage limit of typical lead acid battery decreases by about 5 millivolt per cell for each ° C. rise in the battery temperature.
(5) Output Current Limit
This preferred embodiment provides a current limit servo 30 to provide a signal to PWM controller 10 to limit duty factor to limit the current in the charging circuit. In this embodiment the current limit is set at 21 amps. In the event this limit is reached current limit servo 30 will provide a signal to PWM controller 10 to limit the current to 21 amps.
While the present invention has been described in relation to a particular embodiment, persons skilled in the art will recognize that many potential variations are possible. For example, smaller or larger solar generating systems will require appropriate changes. A small rechargeable battery could be used in place of the C1 capacitor. The maximum power voltage could be determined periodically by forcing a voltage swing on C1 and measuring the current across R1 and then using recorded voltage and current values to calculate the maximum power voltage.
The present invention has many obvious applications other than RV's. All that is needed is a little sunshine and a location some distance from a utility power grid. For these reasons the scope of this invention is to be determined by the appended claims and their legal equivalents.
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A controller for a solar electric generator that permits the generator to produce power substantially at its maximum capacity. Power is transferred from the generator to a temporary electric storage device that is periodically partially drained of power to maintain the temporary electric storage device at a voltage corresponding to the voltage needed by the generator to provide maximum generator power. The electric power drained from the temporary storage device is used to charge conventional batteries. In a preferred embodiment, the temporary storage device is a capacitor that is part of a buck regulator operating at 50 kHz with duty factor control between 0% and 100%. This buck topology switching type regulator provides the periodic draining. In the preferred embodiment control of the duty factor of the buck regulator is utilized to limit current, to prevent battery over charging, to test for the voltage corresponding to maximum power, and to operate the solar generator at is maximum power voltage. When operated at its maximum power operating point, the output to the battery is constant power, providing greater battery charge current than prior art controllers.
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BACKGROUND OF THE INVENTION
The present invention relates to the field of magnetic resonance liquid sample changers. More specifically, the invention relates to the narrow field of automatic magnetic resonance liquid sample changers for use with a significant number of liquid samples to be consecutively analyzed.
Magnetic resonance spectroscopy is an aspect of analytical chemistry which includes Nuclear Magnetic Resonance (NMR) spectroscopy. This technique is used to determine the characteristics of a particular sample and to identify basic structures and compositions of that sample based on a resulting spectrum. In some industrial and educational applications it has often been desirable to prepare a large number of similar samples for NMR analysis. After preparation of these samples each needs to be entered individually into an analysis chamber, analyzed and removed from the chamber. The aforementioned procedure may be performed either manually, in which case the operator, loads and unloads the samples by hand, or automatically, using an apparatus such as the one shown in European Patent Number 0197791 A2 to Smallcombe and Codrington. The former method is obviously costly and time consuming for the operator while the latter, although not necessarily quicker, frees up the operator to tend to other matters. In some instances the automatic sample changing system may run completely independent after initial activation, allowing samples to be analyzed overnight or over the weekend at minimal cost. It would seem that these reasons have led those skilled in the art to view the field of automatic magnetic resonance sample changers differently than the field of manual magnetic resonance sample changers. That is, those skilled in the art have considered the field of automatic sample changers to be a progressive improvement over the manual sample changer field, and therefore they do not necessarily look back upon this field to progress further. Likewise, because of the differing spin velocities, and sample preparation requirements of liquids and solids these two fields of NMR are also very different.
The availability of automatic liquid sample changers in magnetic resonance spectroscopy has been known by those skilled in the art for some time. Independent automatic insertion, analysis and removal of liquid samples has led to a number of U.S. and foreign patents over the years. However, prior to the present invention some basic problems remained which negatively affected the overall system reliability as well as posed some special analyses difficulties for the spectroscopist. These problems included, but were not limited to, the use of an affirmative means, such as compressed gas, to eject samples from the magnetic field after analysis and the time consuming task of fitting each and every sample tube with its own, often bulky, spinner.
Difficulties encountered when using a compressed gas for ejection were sometimes related to the inaccuracies of gas pressure control, resulting in too little or too much pressure. Others skilled in the art have noted that under such conditions samples could either fail to reach an exitable point or they could eject in a rather unpredictable manner from their analysis positions. U.S. Pat. No. 4,859,948 to Kuster utilizes an adjustable control valve to regulate the quantity of compressed gas used in ejecting the sample containers. This approach typifies that taken by those skilled in the art as one to compensate for a limitation rather than one which attempts to overcome the reason for the limitation.
Another difficulty occurred when a spinner served a dual purpose--acting as the sole support for the sample as well as the spinning mechanism, as in U.S. Pat. No. 3,796,946 to Utsumi. Positioned usually in the middle 3/4 of the sample tube, the spinner as a support offered little in the way of stabilization. Instead, the inherent wobble of a sample container would be accentuated at the distal ends of the container, with the greatest degree of wobble occurring at the heavier closed end located within the analysis area of the NMR spectrometer. This aspect has created the problem of undesirable spectral sidebands during the spinning of the sample in analysis. Because solid samples are spun at rates which are magnitudes greater than those of liquid samples, the problem of sample wobble in solid NMR was not analogous to the problem of sample wobble in liquid NMR. This is essentially one reason the two fields are so distinct from one another.
Another difficulty commonly accepted by those skilled in the art was the use of a single passage or opening for the insertion and removal of the samples. This significantly limited the speed with which samples could be changed because a sample would have to be removed completely before a subsequent sample could be inserted. In U.S. Pat. No. 4,581,583 to Van Vliet et al., the principal objective as stated was to increase the rate of changing samples. But even with this narrow focus Van Vliet failed to realize, among other things, the value of separate entrance and exit openings to enhance the potential speed with which samples could be analyzed.
An important commercial problem encountered in the prior art is one of an economic nature. That is, prior to the present invention other systems were so complex in design that their cost had been a significant deterrent to companies or other institutions which would have otherwise benefitted from such a system.
While at first glance some of these difficulties might seem easily resolved, it appears that in the general field of magnetic resonance spectroscopy a dichotomy exists between the theorists and the mechanical technicians. On the one hand, the theorists are devoted almost entirely to the advancement of their field through discovery based on theory-related principles. They spend little time on the mechanically-orientated aspects of magnetic resonance devices. On the other hand, the technicians, while often capable of designing mechanical accessories, were typically unaware of the specific problems that existed, making it difficult for them to either recognize the need for or to conceptualize the present invention.
The problems, as explained above, were dealt with in a number of ways by those skilled in the art. Some designs were put forth in which samples were inserted by a mechanical ram into a spinning air motor device located within the analysis area of the magnetic resonance spectrometer. This may have eliminated the use of individual spinners and ejection air but created other significant reliability problems. The use of mechanical parts to perform any function usually requires an increased amount of repair and replacement occurrences. To maintain reliability of mechanical systems there has always been the likelihood of increased cost.
Others concentrated on the spectral sideband problem, attempting to stabilize the sample during spinning by using a heavy spinner or a larger spinner for increased surface contact. This approach required an increase in the velocity of the spin and ejection air to overcome the higher coefficient of friction and lifting requirements of a heavier sample. This technique is the one employed by Utsumi. Large stabilizing blades are supplied to steady the sample in rotation as they also frictionally engage the sample tube holder to act as a support.
In order to solve these and other problems encountered in the field of automatic magnetic resonance sample changers, the present invention was developed. By supplying not one, but two separate openings the samples may be inserted into one and removed from the other. Furthermore, by linking these separate openings vertically the sample may be carried into the analysis area by gravity, and more importantly the sample may also exit the analysis area by gravity. The present invention has fewer mechanical parts to wear out or maintain and the present invention needs no failure-prone compressed air to eject the sample. To overcome the problems caused by the use of individual spinners the present invention has been designed to utilize a component essential to liquid state NMR analysis--the sample container cap--to efficiently spin the sample.
While the basis of the present invention could be considered to be relatively simple, it is a fact that those skilled in the art of automatic magnetic resonance sample changers failed to realize the proper combination and selection of elements to overcome a combination of prior limitations. Although the implementing arts and elements of the present invention were available, those in the field focusing on the problems of a proper automatic sample changer had not been able to solve these problems. The preconception that a single opening was a given, resulted in those skilled in the art teaching away from the direction of the present invention. While there had been substantial attempts by those skilled in the art at overcoming the problem of undesirable spectral sidebands in magnetic resonance spectroscopy, until the present invention such attempts had not resulted in an adequate economical solution to the problem.
Finally, the seeming presence of a dichotomy in skill levels in the field of NMR spectroscopy made solutions even more difficult. One group possessed an appreciation of the aforementioned problems but not the ability to successfully design a solution. The other group, while possessing the mechanical skill, was lacking a perception of the particular problems stated above and an appreciation that changes could be made in most systems without impacting their scientific capabilities. Just such a communication "gap" had caused designers to retain many restrictions even after the reason for the restrictions had gone. For instance, restrictions imposed by the use of electro-magnets in NMR spectrometers need not have been imposed once superconducting magnets were utilized. In these systems mechanical and/or electrical components and assemblies were typically located beneath the analysis area, requiring samples to be removed through the top. Now with the longer super-conducting magnets, chambers can lend themselves to separate entrance and exit openings.
As an instructive guide to show the direction taken by some persons skilled in the art and the focus of their inventions, the following information is submitted. It is not an intent to imply that each should be necessarily considered relevant to the disclosed invention, rather only to demonstrate the problems encountered in the general field of magnetic resonance sample changers and how differently they were dealt with compared to the approach of the present invention.
U.S. Pat. No. 3,796,946 to Utsumi, et al., relates to a sample intake means for inserting and removing a sample from a magnetic resonance spectrometer. It operates by lifting the cover to raise the sample tube holder, and then closing the cover to lower the holder into the analysis area. This is all done manually rather than automatically.
U.S. Pat. No. 4,088,944 to Engler, et al., discloses a turbine for centering the sample tube in the same rotational axis. The tube is frictionally engaged at two locations proximal to its lower end, thereby reducing the wobble of the tube.
U.S. Pat. No. 4,091,323 to Landis is an automated sample changer for NMR Spectroscopy. A robotic arm is maneuvered up, down, back and forth by pneumatic means controlled by a gas fluidics circuit. Samples are subsequently inserted into and removed from an upper opening in the spectrometer guide tube.
U.S. Pat. No. 4,581,583 to Van Vliet and Gordon is an automatic sample selecting and positioning apparatus which utilizes individual spinners, as well as ejection air. Samples are inserted and ejected through the same opening in the top of the spectrometer and replaced to their original position in a sample carousel.
European Patent Number 0197791 A2 issued to Smallcombe and Codrington pertains to an automated apparatus for presentation of samples to an NMR spectrometer. However, the focus seems to be the use of coding labels, and an optical detection channel for identifying samples before, during and after analysis. Each sample is subjected to the mechanical handling of a robotic arm which serves to grab the sample, place it in the spectrometer, then remove the sample and put it back in the rack.
U.S. Pat. No. 4,859,948 to Kuster relates to manual sample changers for use with large magnet arrangements. The sample carrier is lowered into and ejected from the upper opening of the guide tube via pressurized gas. One of its key features is that it requires little space to operate.
U.S. Pat. No. 4,859,949 to McKenna discloses an automatic sample changer which frictionally engages the sample container at two locations during analysis. Sample containers are inserted and removed from a single opening in the spectrometer guide tube.
While each of the aforementioned patents represents a significant invention in their respective fields, those related to magnetic resonance automatic liquid sample changers have not utilized the combination of key aspects of the present invention to accomplish their individual goals.
SUMMARY OF THE INVENTION
Generally, the goals of the present invention are to provide both a method and device which allows for the automatic insertion, analysis and removal of a liquid sample in a magnetic resonance spectrometer.
It is broadly an object of the present invention to provide a design which serves to utilize gravity to deliver samples into the spectrometer analysis area from a storage rack, and then allows the samples to be removed from the spectrometer analysis area and placed into a separate storage rack utilizing gravity.
It is a further object of the present invention to provide a design which serves to delocalize the inherent wobble of the sample container to an area distant from the spectrometer analysis area. Still a further object of the present invention is to support the sample container at its closed end to delocalize the wobble from the spectrometer analysis area.
Another object of the present invention is to provide a design which utilizes a shorter sample container and a unitary cap/plug and rotor device to substantially eliminate the inherent wobble of the sample container during spinning, by allowing the sample container to be supported in proximity to its upper end by the injected spin gas. It is still a further object to support the sample container in proximity to both ends to substantially eliminate the spin wobble of the sample container.
Another object of the present invention is to provide a design which achieves an increased rate of sample analysis. It is therefore an object of the present design to allow the sample container to pass straight through the probe, rather than exiting the same direction from which it entered. It is therefore a further object of the present invention to provide a design with separate entrance and exit openings to facilitate automatic analysis with a multiplicity of samples. It is also an object of the present invention to allow the NMR samples to be pre-heated or pre-cooled to a required temperature before entering the analysis area of the spectrometer. This aspect allows for an increased rate of sample analysis as well.
It is a further object of the present invention to increase overall system reliability. It is therefore a further object of the present invention to minimize the number of mechanical parts. It is also an object therefore to more efficiently utilize the effect of the earth's gravitational field to transport the sample containers from a first rack to the analysis area, and then further into a second rack after analysis.
Still another object of the present invention is to design an inexpensive, reliable automatic liquid sample changer for use with a magnetic resonance spectrometer. It is therefore an object of the present invention to minimize the mechanical parts utilized in the operation of multiple sample analysis.
Naturally, further objects of the present invention are disclosed throughout other areas of the specification and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of one embodiment showing one sample container seated upon the support and ready to be spun. The arrows show the direction of movement of the two racks.
FIG. 2 is a cross-sectional view of the same embodiment shown in FIG. 1, except the sample container is shown partially exited from the analysis area.
FIG. 3 is a perspective view of the unitary cap/plug device.
FIG. 4 is a perspective view of a shortened sample container.
FIG. 5 is a perspective view of the sealing device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As can be seen from the drawings, the basic concept of the present invention involves several different aspects. Referring first to FIG. 1, first storage rack (4) holds a plurality of sample containers (2) in an analysis ready condition. First storage rack (4) is designed with a plurality of individual compartments (18) and may hold a large number of sample containers (2) depending on the quantity of samples to be analyzed and the space available. In operation, sample container (2) is fed into upper opening (6) in sample container guide tube (henceforth, guide tube) (3), falls, as a result of gravity, and comes to rest on support (13a), shown in its closed position. At this point, a substantial portion of sample container (2) is surrounded by analysis area (12) of the spectrometer, and is ready to be spun for analysis.
A spin gas is injected through spin air injectors (14) located, in this embodiment, above analysis area (12). The sample is then analyzed by any of the methods known to those skilled in the art. After analysis, support (13b) is retracted to the open position, shown more clearly in FIG. 2. Sample container (2) drops, again as a result of gravity, through lower opening (7) to rest in second storage rack (5) where it may be retained indefinitely. This process is, of course, repeated for each of the samples to be analyzed.
The detailed structure and operation of this embodiment of automatic sample changer (1) can be more completely understood when explained in three separate stages. The first of these stages is the pre-analysis stage, which deals with most aspects of the present invention realized or occurring before magnetic resonance analysis. For the second and third stages, the analysis stage and the post-analysis stage, respectively, a detailed discussion is also provided.
In the pre-analysis stage each material to be analyzed is prepared in a suitable manner commonly known to any person skilled in the art of NMR spectroscopy. Referring to FIG. 4, the prepared sample is contained within a number of sample containers (2) needed to efficiently perform the analysis. Each sample container (2) should be sealed, preferably with unitary cap/plug device (8) shown in FIG. 3 or sealing device (17) shown in FIG. 5, to prevent contamination of the sample or spillage. Another aspect of unitary cap/plug device (8) or sealing device (17) which will become more apparent later, is that they allow sample containers (2) to be spun by the injected spin air from spinning air injectors (14) as shown in FIG. 1. Sample containers (2) are then positioned within each individual compartment (18) of first storage rack (4), as shown in FIG. 1. A means for progressively moving first storage rack (4) is used to move first storage rack (4) laterally across upper opening (6), for reasons which will be understood later. The means for progressively moving is preferably, in this embodiment, a pneumatic system, but may be electrical or mechanical if desired. By the term " progressively" it is meant that first storage rack (4) is actuated in a direction which positions the next desired compartment (18) above upper opening (6). The prior art reveals a number of distinct styles for storage racks ranging from double-row concentric carousals to smaller straight-line cartridges.
With reference to FIG. 1, a single sample container (2) is positioned upon support (13a). Support (13a) is preferably made from a material with a low coefficient of friction, such as TEFLON, and/or support (13a) can be supplied with a low velocity bearing air to levitate sample container (2) slightly above support (13a). This is merely a passive support means and should be understood to differ from those of the prior art which frictionally engage the sample container by a more affirmative means. The means for delivering sample container (2) from storage rack (4) to support (13a) is accomplished as follows. Storage rack (4) is slidably mounted to move laterally across upper opening (6) in a fashion such as to align compartment (18) with upper opening (6) and allow sample container (2) to drop through upper opening (6) in guide tube (3) until it rests upon support (13a). Certainly there are a number of ways to laterally move storage rack (4) such as mechanically, electronically, pneumatically or even manually. It is important to note that although sample container (2) is light-weight and durable enough to withstand the short fall, cushion air or other means may be provided, if necessary, as a precautionary measure. Guide Tube (3) plays a limited role in each of the three stages and is a well-known component of magnetic resource spectroscopy. Unique aspects of guide tube (3) will be explained in the post analysis stage.
Now the sample is ready for the analysis stage, and the enhanced analysis characteristics of the present invention may be understood with reference to FIGS. 1 and 2. As stated earlier, a portion of sample container (2) proximal to closed end (15) is shown to be enclosed by analysis area (12). In the present embodiment, closed end (15) of sample container (2) is in direct contact with support (13a)--necessitating the use of a near frictionless surface and/or bearing air. Supporting sample container (2) in this fashion aids in delocalizing the inherent wobble of sample container (2) from analysis area (12). That is, the wobble is significantly decreased at closed end (15). To further increase the stability of sample container (2) a small notch is shown in support (13a). Sample container (2) is positioned into this notch to reduce any wobble at closed end (15). Others have tried to lower certain tolerances to decrease this wobble, but focusing the wobble to an area outside of analysis area (12) has not, until the present invention, been entirely successful. Although, as will be understood later, the present invention also provides for the substantial elimination of wobble in other applications. Still referring to FIGS. 1 and 2, unitary cap/plug device (8) is positioned between a plurality of spinning air injectors (14). A plurality of scalloped "notches" are located on the exterior circumference of rotor portion (11) of unitary cap/plug device (8) and sealing device (17). A supply of air (not shown) may be a gas of any suitable nature, stored in a safe and convenient manner, and delivered to injectors (14) by any of the means previously known to those skilled in the art. Injected air proceeds to communicate with the scalloped "notches" of rotor portion (11) of unitary cap/plug device (8), as shown in FIG. 3, which results in the rotation of sample container (2). As will be understood later, unitary device (8) may also have vortex portion (10) to assist in improving the NMR spectra.
A key aspect of the present invention which helps to significantly eliminate the overall wobble of sample container (2) is the location of spinning air injectors (14). Sample container (2) is designed shorter than the conventional container and therefore remains entirely below spinning air injectors (14) when seated upon support (13a), while unitary cap/plug device (8) enters the path of the injected stream of spin air. This allows the injected spin gas to serve as a stabilizing means at an area slightly above the top of sample container (2), placing sample container (2) entirely between two stabilizing means during spinning and analysis. When used in conjunction with support (13a) wobble is significantly eliminated during spinning. This method of stabilizing support is also a passive support which is distinguishable from the more affirmative supports of the prior art which frictionally engage the sample container. Multiple supports inherently add stability, while positioning the supports at opposite ends of sample container (2) further enhances this stability.
Referring now to FIG. 2, the post-analysis stage is shown with support (13a in FIG. 1) now in an open position shown at (13b). The opening of support (13a) to the open position shown at (13b) is preferably accomplished by a pneumatic system, but may utilize electrical circuitry or a mechanical means if desirable. Sample container (2) is acted upon by gravity and falls through lower opening (7) of guide tube (3) and into second storage rack (5). At the time of release of sample container (2) from support (13b) the next-in-line sample container (2) resting in storage rack (4) may be inserted for analysis. The diameter of unitary cap/plug device (8) is essentially equal to or less than the outer diameter of sample container (2). This allows device (8) and container (2) to pass straight through guide tube (3), utilizing gravity, without making special allowances in the diameter of guide tube (3). The utilization of gravity in this application is believed to be completely unique to this field. That is, the means for removing sample container (2) out of analysis area (12) after retraction of support (13b) includes the effects of gravity. Other sample handling techniques include lifting or mechanically removing samples from their analysis positions. Other elements may assist in the removal of sample container (2), such as guide tube (3) which serves merely to maintain sample container (2) in a vertical position and the supply of cushioning air, if utilized, which is merely to slow the decent of sample container (2) before reaching second storage rack (5). An important note is that without either of these enhancements, sample container (2) would likely descend the short distance to storage rack (5) in much the same fashion.
Second storage rack (5) may be similar in design to first storage rack (4) in that it is slidably mounted with its own means for progressively moving and should be capable of holding at least the same number of sample containers (2). An essential difference is that storage rack (5) is obviously mounted below lower opening (7) of guide tube (3) and is moved in a fashion such that each exiting sample container (2) enters a vacant chamber in storage rack (5). Second storage rack (5) may also require design features different from the features of first storage rack (4) in order to accommodate different space requirements. Furthermore, because sample container (2) is free falling from support (13b) it may be desirable to equip second storage rack (5) with a cushioning means, such as foam rubber or the like, along its bottom surface.
As alluded to earlier, guide tube (3) has a characteristic unique to the present invention. That is, sample container (2) enters at one end of guide tube (3), namely upper opening (6), and exits through lower opening (7), which should be located in proximity, if not at, the opposite end of guide tube (3). This allows gravity to play a large role in the transportation of sample container (2).
Several distinguishable needs drove the development of the present invention. The first was the perceived need for enhanced reliability in an automatic liquid sample changer. This need was recognized and even addressed in other patents. None of these patents solved the need in the fundamental manner of the present invention. One of the major factors which sets the field of the present invention apart from fields in which samples are manually handled is the requirement of unattended operation. This naturally made reliability of the spectrometer system a necessity. However, with other automatic sample changers the duty of handling was merely passed on to robotic arms, push-rods and the like. This is in sharp contrast to the present invention which minimizes all types of handling, especially such mechanical handling, to enhance reliability. Once sample container (2) is placed into first storage rack (4) after preparation there should be no substantial need again for the container to be gripped, pushed, held or otherwise directed by hand. In addition to enhancing operational reliability the present invention helps to prolong the life of each sample container (2) by minimizing scratches, cracks or breaks which might otherwise occur.
Another novel aspect of reliability is the inherent safety mechanism of the present invention. In the event that a sample becomes jammed or there is some type of malfunction to the system, there is no mechanical arm or rod to exacerbate the problem by packing more samples into the system. By minimizing the number of mechanical pars needed to change samples in a spectrometer, the sample handling apparatus of the present invention will likely have causes less "wear and tear" from use which, in turn, will require less maintenance and provide a high standard of reliability over the entire life of the spectrometer system.
A second aspect addressed by the present design is that of greater economy. Prior automatic sample changers have become prohibitively expensive for many applications. As mentioned, the present invention avoids complex mechanisms; this, in turn, reduces the cost to fabricate. In addition, designed into the system is unitary cap/plug device (8) which does not require the expensive machining aspects of rotors with relatively high tolerances. Other design features mentioned earlier such as the minimal handling and safety mechanism help keep system maintenance and replacement costs to a minimum.
A principal need addressed by the design of the present invention is that of enhancing the processing speed of the system. That is, certain aspects of the present invention enhance the rate at which samples may be put through a magnetic resonance spectrometer. There is minimal handling of sample containers (2), so samples arrive quickly to analysis area (12). There is also the straight through concept which allows sample container (2) to enter and exit at separate openings. This feature enables consecutive sample containers (2) to be exiting and entering at substantially the same time, as long as support (13a) is in a closed position (as shown in FIG. 1) before entering-sample reaches the support (13a). This is unlike the sample changers of the prior art which require the complete removal of one sample container before the subsequent insertion of the next. In addition, an optical sensing means (20) positioned in proximity to both upper opening (6) and lower opening (7) the near simultaneous insertion and removal of subsequent sample containers (2) may be closely monitored to further enhance reliability. Optical sensing means (20) may be any of the various devices or methods practically used for such an operation.
The introduction of a thermostatting device (not shown) into first storage rack (4) may further enhance the speed of analysis. Typically, samples are inserted by an automatic sample changer and a certain amount of time is required for the sample to reach a required analysis temperature. In this embodiment each sample is brought to the proper analysis temperature while positioned in first storage rack (4) by the thermostatting device. The sample temperature may be raised or lowered as required. This allows an almost immediate analysis of the sample when it reaches analysis area (12). For some applications a thermostatting device may also be used in second storage rack (5) to keep the samples at an optimal temperature until a later time when they can be properly stored. The thermostatting device may be any of the means known by those skilled in the art for controlling the temperature of samples.
Another key need relates to enhancing the quality of the spectra obtained. As mentioned there are aspects of the present invention which help to eliminate wobble of sample container (2) within guide tube (3). This, or course, produces better resolution of the sample thereby reducing undesirable sidebands in the NMR spectra. Aspects of the present invention which address this goal include the use of shortened sample container (2), multiple supports at opposite ends of shortened sample container (2), and support (13a), as mentioned earlier, in conjunction with the passively supporting spin air. Also, the use of unitary cap/plug device (8) with vortex plug section (10) aids in eliminating the liquid vortexing which further impedes NMR spectra. A common, well-known problem in liquid NMR is the distortion apparent on some spectra due to the vortexing of the liquid sample--caused by the rapid spinning of sample--enclosed by the analysis area. The use of a vortex plug to prevent this occurrence is well known by those skilled in the art. However, with the shortened stature of sample container (2) in this embodiment a plug which is integral to the sealing device is preferable. The integral elements of unitary cap/plug device (8) make it no longer necessary for three separate devices to be used to spin sample, seal sample and avoid liquid vortexing. Instead, a single device--with consolidated elements--is added which performs all these functions as well as saves time in the process. With the conventional long NMR tube and the dual purpose of the spinner--to spin and support--a unitary device for sealing and spinning was seemingly never a focus for other skilled designers.
The foregoing discussion and the claims which follow describe the preferred embodiment of the present invention. Particularly with respect to the claims, it should be understood that changes may be made to the invention without departing from its essence. In this regard it is intended that such changes will still fall within the scope of the present invention. It simply is not practical to describe and claim all possible revisions to the present invention which may be accomplished. To the extent such revisions utilize the essence of the present invention, each would naturally fall within the breadth of protection encompassed by this patent.
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An automatic liquid sample changer for use with a magnetic resonance spectrometer and having separate upper and lower openings in a sample container guide tube to allow a sample container to pass into an analysis area from a superior positioned storage rack, and then subsequently from analysis area into an inferior positioned storage rack, and wherein gravity acts as the means for transporting a sample container through the system. Air bearing or other supports which do not frictionally engage sample container are used to delocalize spin wobble of sample container within sample container guide tube. The first, also acting as a spin drive is proximal to open end of sample container. The second is proximal to the closed end of sample container. A unitary means for sealing, rotor and vortex plug device enhances spectra, aids in reducing wobble and maintains a proper seal of sample container. Economical as well as reliability characteristics are realized as mechanical parts have been minimized and both ejection air and mechanical arms are eliminated.
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[0001] The invention relates to the authentication of merchandise units, and in particular, to authentication after final purchase of merchandise units identified by unique identifiers.
BACKGROUND OF THE INVENTION
[0002] Counterfeiting, the illegal manufacturing and selling of brand copyright-protected articles, poses a huge and still increasing threat to global businesses—including organizations in the life sciences, consumer products, media, apparel, luxury goods, and food and beverages industries. Likewise, stolen merchandise which is then resold through traditional or “parallel” distribution channels seriously affects trade market in general.
[0003] According to the U.S. Customs and Border Protection, the total domestic value of the fake goods seized in fiscal year 2010 was $188.1 million. That corresponded to an estimated manufacturer's suggested retail price totaling US$1.4 billion, if the products were legitimate.
[0004] According to U.S. Immigration and Customs Enforcement (ICE) Director John Morton, “The protection of intellectual property is a top priority for Homeland Security Investigations, as counterfeit products represent a triple threat by delivering shoddy and sometimes dangerous, goods into commerce, by funding organized criminal activities and by denying Americans good-paying jobs”. Trade in counterfeit and pirated goods poses significant threats to the innovation-based economies, including the US and Europe. According to the Organization for Economic Cooperation and Development, the value of counterfeit goods that crossed international borders in 2007 was more than $250 billion.
[0005] Major repercussions of these activities include of course loss of revenue for the enterprise, but undermine the trade market globally. It is threatening branding, intellectual property, and research and development. It might carry along also a negative impact on brand image when customers eventually realize they are not getting the quality of products they come to expect from the trademark or the quality label they thought they own. In other cases, particularly when relating to luxury goods, even when customers receive legitimate merchandise, their perception of value and uniqueness may be reduced when they see counterfeit merchandise in the hands of other consumers. Finally, counterfeiting and piracy also affect the labor market, as many jobs are lost as a consequence of these fraudulent activities.
[0006] Counterfeited merchandise may be inserted in the distribution channel at varied points. The state of the art already includes a number of methods that can be used to control or alleviate the introduction of fake merchandise on these legitimate channels. One problem that has not been satisfactorily solved is the distribution of fake merchandise though “secondary” channels, i.e., channels that, in essence, only sell fake merchandise, and, in many cases, with the buyer/consumer having full knowledge that the merchandise is not legitimate. For these cases, manufacturers can only find mild protection, by means of a number of techniques that produces tags or other devices which are hard to reproduce. This is, however, an incomplete and unsatisfactory solution. First, there is high cost in producing these hard-to-reproduce tags. Second, if a close enough version can be produced, this may be enough to many buyers. After all, many buyers may be fully aware of the nature of the fake merchandise. In such cases, the legitimate manufacturer is left with the high cost of producing such a tag, while the illegitimate manufacturer may get away with a lower cost tag. And third, if said tags are stolen, they cannot be differentiated from the legitimate ones at all.
[0007] Thus, there is need for improved technologies that provide disincentives for consumers to knowingly acquire fake merchandise.
[0008] FIG. 1 depicts a simplified standard process from a merchandise manufacturing to the merchandise selling, as illustrated with bold arrows. Brand Company 100 orders a limited series of objects, or items, to a manufacturer 105 .
[0009] After production of object's series, manufacturer, using a means for transportation 110 (air freight, marine transport or by road), sends the object's series to a wholesaler 115 who is in charge to dispatch subset of object's series to various trusted retailer 125 . Wholesalers use generally transportation by road ( 120 ) for delivery to retailer.
[0010] Finally, the retailer 125 sells the branded goods to a customer 130 . Today, large distribution companies take in charge the objects from the manufacturer to the retailer. Thin arrows depict samples of counterfeited objects and different means to distribute these counterfeited objects to customers, as well as branded goods that are stolen before being sold. A counterfeiter 135 produces copies of branded goods and via a dishonest dealer 140 distributes said counterfeited branded goods directly to the customer 130 or re-injects them in the normal distribution chain with or without the complicity of a third party working in this normal distribution chain. Re-injection of counterfeited branded goods may be done at different levels of the distribution chain as the transit 110 , the wholesaler 115 , the distribution 120 , or finally the retailer 125 . So, even if a customer buys a branded good in a shop, he/she has no guaranty about the authenticity of said branded object. Likewise, branded goods stealing may be done at different levels of the chain by thief 145 : in the manufacturer area 105 or in the distribution chain at the transit 110 , the wholesaler 115 , the distribution 120 , the retailer 125 , or, even the customer 130 . Furthermore, the theft may be assisted or facilitated by one of the parties in the chain, or by an employee of said part. For example, a manufacturer may overproduce certain merchandise with intent to sell it through an unauthorized channel.
[0011] A customer 130 who buys this stolen branded good directly from thief 140 or 145 generally knows that the object has been stolen, or that is not legitimate. This willing customer of illegitimate merchandise constitutes one of the biggest challenges for counterfeiting prevention, and a key focus of the current invention.
[0012] Whatever the way looking at it, counterfeit and theft problems can't and won't be totally eliminated. So existing technology mostly consists in trying to keep them under control on the distribution and manufacturing channels. Existing technologies do that by raising the barriers to casual violations, and by requiring a concerted and even more complex effort by attackers. In the current invention, we describe a method to raise a barrier, or create an inconvenience, to the final customer of illegitimate merchandise. This has not been addressed by any of the existing technologies. With the use of the methods described in the present invention, even merchandise that was stolen directly from the production line can be later identified as have being illegally acquired, reducing its value for the (dishonest) consumer.
[0013] Conversely, by making illegitimate merchandise distinguishable from legitimate ones, we preserve revenue for the brand owner, and increase the value of the merchandise to the consumer, by making sure the value provided by the uniqueness of the product design is not diminished by the proliferation of unauthorized reproductions.
[0014] The scale of the threat is prompting new efforts by multinationals to stop, or at least curb, the spread of counterfeits. Steps have been taken to protect by law, which can be a disincentive for some potential violators of rights. Companies are also more and more pressuring governments to crack down on counterfeiting, trying to ensure a way to protect Intellectual Property.
[0015] There is a need to help brand companies to implement solutions based on strong prevention, detection, and response strategies and tactics.
[0016] As factories across the world gain experience with high-end manufacturing, counterfeits have become more sophisticated as well. Counterfeiters have become so proficient that it can take an expert to recognize a fake product. Even worse, some counterfeit merchandise may, actually, be produced at the same factory, with the same raw material, by the same machinery and personnel. They may, in fact, be identical in all practical aspects; except for they are illegally produced and no royalties have been paid.
[0017] This is one of the reasons why IT-based solutions are envisioned as great technological contributors in acting against counterfeiters, putting innovation to work to protect a global economy itself driven by innovation.
[0018] Some solutions using electronic tagging are being experimented today in specific industries. For instance, a company has developed an electronic pedigree software and provides the expertise to safeguard and secure the pharmaceutical supply chain. This pedigree system, based on a Radio Frequency Identifier (RFID) tag with a unique Electronic Product Code (EPC), tracks all the information about a product as it moves through the supply chain, from the manufacturer all the way to the point of sale. Although this methodology represents a step forward in the war against counterfeiting and theft, a potential limitation rises from the fact that the Pedigree itself could be read and possibly copied or imitated, and then used abusively by fraudulent parties until the illegal procedure is detected and acted upon.
[0019] Other existing technologies create and securely manage a digital Certificate of Authenticity that will be encrypted and uniquely bound to the corresponding product and its accompanying media—a certificate container—. This Certificate may integrate a mechanism for protecting its digital content against unauthorized copy and reproduction. This Certificate would be used to verify and hopefully guarantee the authenticity of a product through a process checking that there is a perfect match between a Product Identifier Code and information derived from its Certificate of Authenticity. This solution, and a number of related solutions, helps a legitimate customer to verify whether a certain product is authentic or not. Note, however, these techniques are useless in combating cases where the customer is willingly buying a counterfeit product. In such cases, the (dishonest) consumer already knows the product is not legitimate.
[0020] Other type of protection involves making hard-to-reproduce tags, and includes some of the most widely used techniques. Older techniques include from simple metallic logos, to holograms, but all these became increasingly easy to reproduce. More recent solutions include complex 3D materials that have unique signatures when read by a dedicated device, these signatures then signed with a digital certificate. Again, these solutions have very weak or no effectiveness against, for example, the case of a customer willingly buying counterfeit merchandise. In particular, even for technologies where the legitimacy could be verified after the purchase, the requirement of proximity to the tag and expensive readers prevents from subtle authenticity verification: the consent and knowledge of the owner of the merchandise is essentially required, making the process too intrusive.
[0021] Thus, none of the existing technologies satisfactorily addresses the problem of the dishonest consumer intentionally acquiring illegitimate merchandise, be it a stolen unit or an unauthorized reproduction.
SUMMARY OF INVENTION
[0022] 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.
[0023] Described herein are various technologies pertaining to provide means to verify the legitimacy of a product. One of the unique characteristics of these technologies is that it can be used to verify legitimacy even after the final purchase has taken place, and that it can be done without explicit consent by the owner.
[0024] In an exemplary embodiment, a serial number or unique identifier is associated with each instance of a legitimate product. An association between a legitimate purchaser of such a product and such unique identifier is performed at time of purchase, and made available for subsequent verification by the general public. In an exemplary embodiment, the association may be the name or a picture of the legitimate purchaser, recorded by the authorized retailer at time of sale. The unique identifier may be a tag containing a unique code, which is visibly displayed when such merchandise is used in public. The verification method may be performed by capturing a picture of that visible identifier, and visiting the manufacturer website to verify the legitimate owner of such merchandise.
[0025] For instance, a consumer called Mary Doe purchases a FancyProducts brand handbag at a legitimate retailer. The handbag has an associated unique identifier, say a wearable tag that visibly displays the bag's serial number, 12345. The (legitimate) retailer has secure access to the manufacturer site AuthRetailer.FancyProducts.com, and upon sale, associates the serial number 12345 to customer Mary Doe. Mary subsequently wears the handbag in public situations. A third party, interested in knowing whether or not the handbag is legitimate, reads or captures a picture of the serial number. Such third party, subsequently visits the public facing portion of the manufacturer website www.FancyProducts.com, and asks for the name of the owner of handbag number 12345. The site than informs such third party that the legitimate owner is Mary Doe, does confirming the legitimacy of the product.
[0026] Note that a counterfeit or even stolen product may look exactly like the legitimate one, and may display a serial number as well. However, the un-authorized seller has no means to update the site to reflect the name of the owner. Thus, any third party trying to verify the legitimacy of the merchandise will get clued in that the merchandise is not legitimate.
[0027] As described in more detail later, other aspects of the invention include alternate ways of displaying a unique identifier that is not a serial number, other ways of identifying the legitimate purchaser that do not include making his or her name public, and aspects to allow the consumer to subsequently transfer or gift the merchandise to a different user. It also includes extensions to usage during the manufacturing and distribution process.
[0028] The above summary presents a simplified summary in order to provide a basic understanding of some aspects of the systems and/or methods discussed herein. This summary is not an extensive overview of the systems and/or methods discussed herein. It is not intended to identify key/critical elements or to delineate the scope of such systems and/or methods. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates the simplified supply chain from a merchandise manufacturing to the merchandise selling, the distribution chain of counterfeited objects, as well as the distribution chain of stolen branded goods.
[0030] FIG. 2 illustrates possible designs for unique identifiers that can integrated into the product design, or on a tag.
[0031] FIG. 3 is a flow diagram that illustrates an exemplary methodology for associating a unique identifier with a customer.
[0032] FIG. 4 is a flow diagram illustrating the methodology to verify the likelihood of authenticity of the product bearing a unique identifier.
[0033] FIG. 5 is a block diagram representing an example of the main components and modules associated with practicing the invention.
DETAILED DESCRIPTION
[0034] Various technologies pertaining to merchandise authenticity verification are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more aspects. Further, 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.
[0035] Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form.
[0036] Further, as used herein, the terms “component” and “system” are intended to encompass computer-readable data storage that is configured with computer-executable instructions that cause certain functionality to be performed when executed by a processor. The computer-executable instructions may include a routine, a function, or the like. It is also to be understood that a component or system may be localized on a single device or distributed across several devices. Further, as used herein, the term “exemplary” is intended to mean serving as an illustration or example of something, and is not intended to indicate a preference.
[0037] Further advantages of the present invention will become apparent to the ones skilled in the art upon examination of the drawings and detailed description. It is intended that any additional advantages be incorporated herein.
[0038] According to the invention, an identifier and one or more entries in an authenticity database are associated to the branded goods to be checked for detecting counterfeiting or theft. The identifier can be associated with the merchandise at any stage in the distribution channel, as early as pre-manufacture, or as late as the final retailer.
[0039] The identifier referred in the previous paragraph can be re-utilized by a number of product units. In such case, the database may have as many entries as units sharing the same identifier. This may be a way of reducing the number of identifiers, particularly in cases where the database provides only confirmation of ownership, as later described in paragraph
[0040] However, in the preferred embodiment, each product unit caries a unique identifier.
[0041] The identifier can be in a form of a tag, or can be incorporated directly in the product design. Traditional identifiers like barcodes, QR codes, digits, alphanumeric codes and the alike are all valid identifiers for the purpose of practicing this invention. More specifically, a handbag or other product could have, either attached on a tag, or directly incorporated into the product a number or code which uniquely identifies each unit of that product. Typically, however, barcodes and serial numbers and alphanumeric codes are not very fashionable as design elements. Thus, particularly for fashion items, other unique identifiers can be used. FIG. 2 illustrates a few instances of unique identifiers that are appropriate for the purposes of practicing this invention. Object 200 is a watch, which in its case has sixteen slots which can be painted in different colors (note that only slots 201 , 202 , 203 , 204 , 205 , 206 , 207 , and 208 are explicitly labeled in the figure). Even if only two states are used (e.g., black and white), a dial with 16 slots would be able to uniquely encode up to 65536 units. If four colors or elements are used, over four billion unique codes exist. Object 220 represents a handbag, where the unique identifier was incorporated into the design, by inserting a combination of predefined elements into pre-defined position. More specifically, position 221 , the latch, indicates a square design element; position 222 indicates a triangle element; position 223 indicates a cross. Each design element to the left of element 223 can be varied and used as a part of the unique identifier. Again, 16 types of objects in only 5 positions would provide 20 bits, and thus be enough to uniquely identify over one million objects. Drawing 240 represents yet another possible encoding. Here, an umbrella is used as the key representation, and could be a key element on the branding strategy. Each image segment, namely segments 241 , 242 , 243 , 244 , 244 , 245 , 246 , 247 , 248 , and 249 is to be painted with a different color. Finally, note that it may be desirable to insert redundancy in the representation. More specifically, in some instances you may want to insert enough combinations that most combinations are not valid. This can be easily achieved by inserting more elements or more position into the coding. This would prevent the person trying to verify the authenticity from getting the wrong answer due to mistyping one color or character.
[0042] Still in relation to FIG. 2 , element 280 illustrates incorporating the unique identifier on a brand logotype. In this example, the logotype 280 consists of two letters, B and K. Parts of the logotype are adorned with symbols. Each particular printing or embroidering of the logotype to contain a distinct combination of these symbols. In the example provided, each letter in the logotype 280 carries 5 symbols. The five elements in the first letter are marked as 281 282 283 , 284 , and 285 , and consist of a circle, a diamond, a circle, a square, and a donut, respectively. Together with the 5 elements in the other letter, this could be enough to represent over 60 million if the elements are draw from a set of just 6 symbols.
[0043] Finally, 260 illustrates a QR code, which can also be used as a unique identifier. Other examples of barcodes include the Microsoft Tag, and other mechanisms that can easily be read by automatic means.
[0044] Note also that while visible identifiers are a preferred embodiment, non-visible identifiers can also be used, as long as they can be read by a third party. Examples include RFID, ultraviolet markers, digital watermarks, and others.
[0045] According to the invention, information about the legitimate owner of the product has to be uploaded to a database before public use of the product containing the unique identifier. This can be done in a number of manners. In a preferred embodiment, described in the next paragraph in association with FIG. 3 , the uploading of such information is done by the retailer during the purchase process. Other embodiments include providing an authentication code for the user to upload the information herself, as well as automatic uploading based on information available at time of purchase. Information available at time of sale include data and location of purchase, customer name, zip code, and other information available or that can be obtained in conjunction with credit card, coupons, or other forms.
[0046] FIG. 3 presents an overview of the association recording process. In step 301 the process starts. In step 310 a new unique code is generated. The code may be as simple as a serial number, or much more elaborate, as, for example, a unique color image or drawing, as exemplified in conjunction with FIG. 2 . In step 320 , a product is manufactured, and a readable element is manufactured, containing the unique code. The readable element may be integral part of the product to be protected, or it may be an independent element to be later attached or integrated into the product. In step 330 the products are transported and/or distributed to the authorized retail locations. In step 340 the retailer obtains the required personal information about the buyer. In step 350 , the retailer accesses the manufacturer database, and uploads said buyer's information, associating that particular info with the unique identifier of the product sold. In optional step 360 , information is delivered to the client about the authentication process. Such information may include details about the personal data recorded in the database, details about which pieces of that information will be available to the public, and information about how the public may have access to that information. It may also include instructions on how to update or correct such information, including an access code or other required means. In step 399 , the process of finishes.
[0047] Is part of the assumptions regarding the invention that the customer will use the product in public. Is also part of the assumptions, that a customer that would otherwise be willing to wear illegitimate merchandise in public would be embarrassed if other people could easily verify that said merchandise is illegitimate. Is further part of the assumptions that such risk of embarrassment is sufficient, at least to reduce the number of people willing to buy or wear such fake merchandise. Thus, it is a key element of the invention to provide means for a third party to verify information about the legitimacy of a product. According to the invention, verification of legitimacy is done by verification of ownership. An example method for the verification process is described in the next paragraph, in association with FIG. 4 .
[0048] FIG. 4 illustrates the verification process. In 401 the process starts. In 410 , a third party obtains enough information to identify the unique identifier. This can be done, for example, by taking a picture of the object, as long as the picture includes enough information and resolution to be able to read the details of the identifier. A number of alternative methods for capturing the identifier may also be practical, depending on the type of identifier used. In step 420 , the third party provides the necessary information about the unique identifier, and queries the manufacturer database. In a preferred embodiment, this is done by visiting the manufacturer website, navigating to the correct page, and entering enough information to identify the identifier. In 430 , the website provides the third party with the public information associated with that identifier. The information may include whether or not the identifier is valid, and whether or not it was ever sold. More importantly, it may include personal information about the buyer or owner of the merchandise. This personal information may include a picture of the buyer, his or her name, his or her social site (e.g., Facebook) contact or url, their zip code, or any information enough for the third party to at least partially verify if a match with the bearer of the object is likely. At this point the process may end, as the third party has enough information to compares the public information provided in 430 with his or her own observations of the owner or the use of product with the unique identifier. Based on this comparison, the third party may reach a conclusion on the likelihood of the merchandise being authentic.
[0049] In another embodiment, the process continues, and, in optional step 440 the third party provides personal information about the product, or about the bearer or owner of the product, or about its usage. The system receives such information and, in optional step 450 , compares such information with the corresponding information, public or private, stored in the database in association with the unique identifier. Based on that comparison, in step 460 the systems provides to the third party information about the likelihood of a match, or, in other words, the likelihood of the merchandise being authentic.
[0050] By means of example, if the public information provided by the database in 430 was a picture of the buyer, the third party could compare the picture with his own picture of the person wearing the product, and from that reach his own conclusions about the authenticity of the merchandise. Alternatively, the third party could in optional step 440 upload the picture of the owner, and the system could perform a face recognition based on the face information stored in the database, providing the likelihood of a match in step 450 . A person skilled in the art will be familiar with face recognition software and technologies.
[0051] Privacy may be a concern, depending on the type of information provided by the manufacturer in step 430 . Some users may not feel comfortable with their names being released to anyone snatching a picture of their handbag. We note, however, that by providing a picture of the person, no additional personal information is provided, since the third party had a picture of the person to begin with.
[0052] In another embodiment, as exemplified in steps 440 to 460 , to preserve the privacy of the wearer, only confirmation is give. More specifically, the third party has to provide the unique code, along with a name, zip code, picture, or something else. The manufacturer site simply confirms or denies that the association is correct. A person skilled in the art of passwords and authentication will know techniques that can be used to alleviate a brute force attack, including Human Interactive Proofs, IP based throttling, etc.
[0053] Yet in another embodiment, the detection of the unique identifier is automatically done. More specifically, the third party provides, e.g., by uploading, a picture of the unique identifier, enough information for the manufacturer to recover the unique code, and thus reply with the associated data. In such cases, the unique identifier can be more subtle, e.g., a digital watermark or alike. Existing unique identifier satisfying this requirement for automatic detection include QR codes and Microsoft Tag. Other more fashionable designs can be easily developed and incorporated in a tag or as integral part of the product.
[0054] In Another embodiment, instead of the uniqueness of the identifier being visible, the unique information is imperceptibly embedded in an image or graphic by adding a digital watermark. Automatic detection is done by reading the embedded watermark, included in an image or graphics which is part of, or attached to, the product. In this case, the image is uploaded the manufacturer's server, and the watermarking extracted. In an alternative embodiment, the watermark detector is downloaded to a device. A person skilled in the art will recognize hundreds of ways of embedding and detecting (or reading) such a watermark.
[0055] In another embodiment, instead a graphical element, the unique identifier consists of a device that can be read by electromagnetic means. Examples include RFID and near filed communication devices.
[0056] The identification tag or identifier can be attached to the product at any point in the manufacturing and distribution process. If it is embedded in the product itself, it may, of course, have to be done during the manufacturing process. If it is simply attached to the device, it can be attached closer to the product being transferred to the final customer.
[0057] In any case, an association between the unique identifier and the current owner (e.g., the customer) has to be done before it can be verified by the third party.
[0058] In a preferred embodiment, the unique identifier is associated to the product during the manufacturing process. Then at the final, retail sale, the authorized reseller obtains some personal information about the customer, and associates that to the unique identifier. For example, the retailer may associate a picture of the customer to the specific identifier associated with the unit of merchandise said customer bought.
[0059] When the uploading of the customer information is done by the retailer, it will be necessary to authenticate the retailer or seller. A person skilled in the art will be familiar with a number of ways of authentication, including passwords, hardware tokens, etc. In a preferred embodiment, the manufacturer has a list of unique identifiers belonging to the retailer, and currently for sale. Even after authentication, the retailer is only authorized to upload associated with those unique identifiers. Depending on the way the technology is used, the retailer, after associating the customer with a unique identifier, may lose access to further modifications of that information.
[0060] In another preferred embodiment, the object containing the unique identifier is also associated with an authentication code that allows a customer to modify the information associated with the unique identifier after the purchase. For example, if the merchandise is bought as a gift to someone else, the retailer may leave not update any information to the site, or may associate the product with the purchaser. The purchaser, or final owner of the product, then uses such code to update the centralized database with the correct information of the final product user or owner.
[0061] In another preferred embodiment, such authentication code is a one-time use code. In a preferred embodiment, such code is hidden and becomes evident it was read. This can be achieved, for example, with scratch codes, as used in lottery tickets and the alike. In yet another embodiment, it is a one-time code, but a new one time code is automatically generated online whenever the last issued code is used.
[0062] The information is stored in a database or other storage mechanism under the control of the manufacturer or brand owner. FIG. 5 illustrate a possible organization of such database, and means for accessing and modifying it. The server or servers 500 contain a storage unit where the database 510 is stored. The database contains all information regarding each unique tag, as explained elsewhere in this application. A retailer 550 , or, more specifically, an agent or employee acting on behalf of the retailer, accesses the server 500 by connecting a local computer or other computing device 550 through a dedicated webservice 530 . The webservice first authenticates the retailer by consulting the authentication module 520 . The authentication process may be one of a number of authentications mechanisms, including but not limited to passwords, tokens, smartcards, SecurID, or other. Note also that this authentication can be persistent. A person skilled in the art will be familiar with a number of efficient authentication technologies. After being authenticated, the retailer has access to read and modify a number of entries in the database. More specifically, since each unique identifier has an entry in the database, and since the retailer has a number of these products for sale, there is one entry in the database corresponding to each unit of the products the retailer currently has in stock. The retailer has access to verify the status of these. More importantly, the retailer has access to modify these entries, for example, by associating it with the customer buying the merchandise. In a preferred embodiment, after the association is performed, the retailer may lose access to modifying such entry. In a preferred embodiment, the retailer may also print information about the association, and provide that to the customer. In one embodiment, the printed material contains enough information to allow the customer to subsequently updates or modify some or all of the information entered by the retailer. In another embodiment, the information printed is only enough to update said database entries when complemented with information contained in the product, or a tag attached to the product, or material included in the product packaging. Said complementary information may only be visible after a one-time operation. For example, it may include a code which is covered by ink, similar to technology sometimes used in lottery tickets and the alike; the user needing to scratch the surface to reveal the code. This is to avoid the risk that a rogue employee secretly copies such code, and subsequently make use of it. A person skilled in the art will immediately envision other mechanisms for accomplishing the same objective.
[0063] Still referring to FIG. 5 , the Customer, after purchasing the product may optionally visit the manufacturer site. Using the credentials provided by the retailer for this purpose, the customer access the server 500 by connecting his computer or other computing device 552 to the server 500 though the webservice provided for customers 532 . The webserver for customer 532 consults with the authentication module 520 and the database 510 to ascertain the legitimacy of the credentials provided. After authentication, the customer is given access to read, modify, or request a modification of a number of private and public information contained in the database, and associated with the unique identifier in the product purchased by the customer. For example, the initials, zip code, and other information may be directly modified. The manufacturer may decide to verify some information before updating. For example, it may require that the picture associated with the entry only be substituted with another picture where the customer can be easily identified. This would, for example, preclude the user to upload his cat's picture, or even some pornographic image. Finally, some information may not be allowed to be modified by the user, even if it's public. For example, the sale date may not be modified directly by the user.
[0064] Finally, and still referring to FIG. 5 , a third party may also connect to the manufacturer server 500 . It may do that by using his computer or other computing device 554 . It connects to the webservice providing information to the general public. This webservice may include product information, or any other information. It also includes a means to access the public information stored in the database 510 . More specifically, it provides means for the third party to provide information relating to a unique identifier. If the information provided is sufficient to identify the entry, the webserver 534 provides to the third party's computer 554 the public information associated with such an entry. For example, the public information may include such personal data as the product owner name, initials, zip code, address, picture, date and place of sale, etc.
[0065] In a preferred embodiment, the public information includes a link, url, or enough other detail as to give access to a public profile of the customer on a social site, e.g., Facebook, MySpace, LinkedIn in, etc.
[0066] In another embodiment, the public information includes a link to a site freely selected by the customer.
[0067] A person skilled in the art will appreciate that the particular kind of information to be considered public or private will depend on the application.
[0068] In another embodiment, there is an application or selection process before a customer can acquire certain merchandise. For example, a university may reserve a certain kind of product only for alumni. The product can then be identified with a unique identifier, wherein the unique identifier, when scanned or entered at an appropriate page at the university site will provide information about the specific alumni which the tag or unique identifier was issued to.
[0069] A similar process can be used for other selective groups. For example, a designer, tired of ugly people wearing his designs, may decide only beautiful people are allowed to use his creations. The selection or authorization process may include an interview at the store, or submitting a picture. Once a customer is approved, that is, authorized to wear that specific brand or design, a unique identifier is associated with him/her, or with each product to be worn by him/her. Note that this can be done either in advance or on the fly. More specifically, if each product already has a unique identifier, all those identifiers can be associated to a single person. Similarly, if the identifiers are produced after the association, many copies of the same identifier can be produced, and thus will all point to the legitimate owner.
[0070] In another embodiment, the user may participate in the design of the unique identifier himself. After the customer proposes the design, the design is checked for collision with existing designs, and, if no collision is found, the design is accepted.
[0071] Note that many aspects of the invention need one or more computing devices to perform various functions. These will include servers, personal computers, smartphones and other existing or future computing devices. Furthermore, as evident from the invention description, information needs to be transmitted between the devices. Such transmission may instant or delayed, and may be performed using the Internet, cellular phone network, or other communication medium. Similarly, each of these computing devices will need to run specialized software to perform the functions described herein. These may include database software, web servers, web browsers, encryption, and others. A person skilled in the art will be familiar with all these, and will easily be able to implement all parts of a system able to perform the teachings described herein.
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The claimed subject matter relates to an architecture to produce disincentives to wearing counterfeit or stolen merchandise in public. In particular, the architecture utilizes a unique identifier associated with each unit of the product, and provides both a registration channel for receiving ownership registration and a verification channel to receive requests for verification. By way of illustration, the architecture can include associating a brand logotype that includes unique markings with each unit of a product, a private web service where the retailer may upload customer information at the time of sale, and a publicly available web service, where a third party may inquire about the ownership of a product containing a certain unique identifier.
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RELATED APPLICATION DATA
[0001] The benefit of U.S. Provisional Patent Application No. 60/736,721, filed 15 Nov. 2005, entitled THERMALLY CONTAINED/INSULATED PHASE CHANGE MEMORY DEVICE AND METHOD, is hereby claimed.
PARTIES TO A JOINT RESEARCH AGREEMENT
[0002] International Business Machines Corporation, a New York corporation; Macronix International Corporation, Ltd., a Taiwan corporation, and Infineon Technologies A.G., a German corporation, are parties to a Joint Research Agreement.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to high density memory devices based on programmable resistive memory materials, including phase change materials and other materials, and to methods for manufacturing such devices.
[0005] 2. Description of Related Art
[0006] Phase change based memory materials are widely used in read-write optical disks. These materials have at least two solid phases, including for example a generally amorphous solid phase and a generally crystalline solid phase. Laser pulses are used in read-write optical disks to switch between phases and to read the optical properties of the material after the phase change.
[0007] Phase change based memory materials, like chalcogenide based materials and similar materials, also can be caused to change phase by application of electrical current at levels suitable for implementation in integrated circuits. The generally amorphous state is characterized by higher resistivity than the generally crystalline state; this difference in resistance can be readily sensed to indicate data. These properties have generated interest in using programmable resistive material to form nonvolatile memory circuits, which can be read and written with random access.
[0008] The change from the amorphous to the crystalline state is generally a lower current operation. The change from crystalline to amorphous, referred to as reset herein, is generally a higher current operation, which includes a short high current density pulse to melt or breakdown the crystalline structure, after which the phase change material cools quickly, quenching the phase change process, allowing at least a portion of the phase change structure to stabilize in the amorphous state. It is desirable to minimize the magnitude of the reset current used to cause transition of phase change material from crystalline state to amorphous state. The magnitude of the reset current needed for reset can be reduced by reducing the size of the phase change material element in the cell and by reducing the size of the contact area between electrodes and the phase change material, so that higher current densities are achieved with small absolute current values through the phase change material element.
[0009] One direction of development has been toward forming small pores in an integrated circuit structure, and using small quantities of programmable resistive material to fill the small pores. Patents illustrating development toward small pores include: Ovshinsky, “Multibit Single Cell Memory Element Having Tapered Contact,” U.S. Pat. No. 5,687,112, issued Nov. 11, 1997; Zahorik et al., “Method of Making Chalogenide [sic] Memory Device,” U.S. Pat. No. 5,789,277, issued Aug. 4, 1998; Doan et al., “Controllable Ovonic Phase-Change Semiconductor Memory Device and Methods of Fabricating the Same,” U.S. Pat. No. 6,150,253, issued Nov. 21, 2000; Chen, “Phase Change Memory Device Employing Thermally Insulating Voids,” U.S. Pat. No. 6,815,704 B1, issued Nov. 9, 2004.
[0010] Problems have arisen in manufacturing such devices with very small dimensions, and with variations in process that meet tight specifications needed for large-scale memory devices. It is desirable therefore to provide a memory cell structure having small dimensions and low reset currents, and a method for manufacturing such structure.
SUMMARY OF THE INVENTION
[0011] A first aspect of the invention is directed to a thermally insulated memory device comprising a memory cell access layer and a memory cell layer, operably coupled to the memory cell access layer. The memory cell layer comprises a memory cell, the memory cell comprising: first and second electrodes having opposed, spaced apart electrode surfaces; a via extending between the electrode surfaces; a thermal insulator within the via, the thermal insulator comprising a sidewall structure in the via defining a void extending between the electrode surfaces; and a memory material such as a phase change material, within the void electrically coupling the electrode surfaces. The thermal insulator helps to reduce the power required to operate the memory material. In some embodiments the memory cell layer comprises an inter-electrode insulator made using a separation material through which the via extends, and the thermal insulator has a thermal insulation value greater than a thermal insulation value of the separation material. The thermal insulator may define a sidewall structure having an inside surface tapering inwardly from the electrode surface of the second electrode towards the electrode surface of the first electrode so that a cross-sectional area of the insulated via is smaller at the first electrode than at the second electrode, forming a void having a constricted region near the first electrode member, the memory material element being at the constricted region. The memory cell access layer may comprise an outer surface and an electrically conductive plug extending to the outer surface form underlying terminals formed for example by doped regions in a semiconductor substrate, the plug having a plug surface, the plug surface constituting a portion of the outer surface; and the first electrode overlying at least a substantial portion of the plug surface; whereby at least some imperfections at the plug surface are accommodated by the first electrode. In embodiments described herein, the electrode surface first electrode is substantially planar, in the region of the via, where substantially planar surface can be formed for example by chemical mechanical polishing or other planarizing procedures that intend to improve the planarity of the electrode surface relative to the electrode material as deposited and prior to planarization.
[0012] A second aspect of the invention is directed to a method for making a thermally insulated memory device. A memory cell access layer is formed on a substrate, the memory cell access layer comprising an upper surface. A first electrode layer is deposited and planarized on the upper surface. A inter-electrode layer is deposited on the first electrode layer. A via is created within the inter-electrode layer. A thermal insulator having an open region is formed within the via, by for example forming sidewall structures on sidewalls of the via. A memory material is deposited within the open region. A second electrode layer is deposited over and in contact with the memory material. According to some embodiments the material of the thermal insulator has a thermal insulation value greater than the thermal insulation value of the separation material used for the inter-electrode layer.
[0013] A third aspect of the invention is directed to plug-surface void-filling memory device comprising a memory cell access layer comprising an outer surface and an electrically conductive plug extending to the outer surface, the plug having a plug surface, the plug surface constituting a portion of the outer surface, the plug surface having an imperfection; and a memory cell layer contacting the memory cell access layer, the memory cell layer comprising a memory cell. The memory cell comprises first and second electrodes having opposed, spaced apart electrode surfaces, the first electrode contacting at least a substantial portion of the plug surface; and a memory material electrically coupling the electrode surfaces to create a memory material element; whereby the imperfection at the plug surface is accommodated by the first electrode. In some embodiments a void-type imperfection at the plug surface is filled by depositing and planarizing the material used to form the first electrode.
[0014] A fourth aspect of the invention is directed to a method for accommodating an imperfection in an outer surface of an electrically conductive plug of a semiconductor device. The method comprises depositing an electrode on the outer service of the plug.
[0015] The method described herein for formation of the phase change element for use in a memory cell in a phase change random access memory (PCRAM) device, can be used to make small phase change elements, bridges or similar structures for other devices.
[0016] Various features and advantages of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a simplified cross-sectional view of a phase change memory device made according to the invention;
[0018] FIGS. 2-11 illustrate a method for making phase change memory devices, such as the device of FIG. 1 ;
[0019] FIG. 2 illustrates the final stages for making the memory cell access layer of FIG. 1 ;
[0020] FIG. 3 illustrates the deposition of a first electrode layer on top of the memory cell access layer of FIG. 2 ;
[0021] FIG. 4 illustrates the result of depositing an oxide layer onto the first electrode layer of FIG. 3 ;
[0022] FIG. 5 shows vias formed in the oxide layer of FIG. 4 ;
[0023] FIG. 6 illustrates thermal insulators deposited within the vias of FIG. 5 ;
[0024] FIG. 7 shows phase change material deposited within the central open regions of the thermal insulators of FIG. 6 ;
[0025] FIG. 8 illustrates a second electrode layer deposited onto the structure of FIG. 7 ;
[0026] FIG. 9 illustrates the formation of a lithographic mask overlying certain areas on the second electrode layer;
[0027] FIG. 10 illustrates the result of etching the structure of FIG. 9 ; and
[0028] FIG. 11 shows the structure of FIG. 10 after deposition of an oxide within the etched regions.
DETAILED DESCRIPTION
[0029] The following description of the invention will typically be with reference to specific structural embodiments and methods. It is to be understood that there is no intention to limit the invention to the specifically disclosed embodiments and methods but that the invention may be practiced using other features, elements, methods and embodiments. Like elements in various embodiments are commonly referred to with like reference numerals.
[0030] FIG. 1 is a simplified cross-sectional view of a phase change memory device 10 made according to one embodiment of the invention. Device 10 comprises broadly a memory cell access layer 12 formed on a substrate, not shown, and a memory cell layer 14 formed on top of access layer 12 . Access layer 12 typically comprises access transistors; other types of access devices may also be used. Access layer 12 comprises first and second polysilicon word lines acting as first and second elements 16 , 18 , first and second plugs 20 , 22 and a common source line 24 all within a dielectric film layer 26 .
[0031] Phase change memory device 10 and its method of manufacturer will be described with reference to FIGS. 2-11 . Referring now to FIG. 2 , memory cell access layer 12 is seen to have a generally flat upper surface 28 , the upper surface being interrupted by voids 30 formed in plugs 20 , 22 and by void 32 formed in common source line 24 . Voids 30 , 32 , or other surface imperfections, are formed as an artifact of the deposition process used for formation of tungsten plugs within small dimension vias. Deposition of, for example, a phase change material directly onto the upper surfaces 33 of plugs 20 , 22 can create a distribution problem, that is create an increased variance in the operational characteristics of the devices, due to the existence of voids 30 .
[0032] FIG. 3 illustrates the results of TiN deposition to create a first electrode layer 34 and chemical mechanical polishing CMP of layer 34 to create a planarized surface 36 . Layer 34 is preferably about 100 to 800 nm thick, typically about 500 nm thick after planarization. First electrode layer 34 fills voids 30 , 32 to effectively eliminate the distribution problem that could be created by the voids or other surface imperfections. Planarization removes artifacts of the voids that result from deposition of the electrode material layer 34 . An inter-electrode layer 38 , see FIG. 4 , is deposited on layer 34 . Layer 38 may comprise one or more layer of an electrical insulator such as silicon dioxide, or variants thereof, is preferably about 40 to 80 nm thick, typically about 60 nm thick for the illustrated example. Vias 40 , see FIG. 5 , are formed in inter-electrode ayer 38 , typically using an appropriate lithographic mask, not shown, generally centered, within alignment tolerances of the manufacturing processes, above plugs 20 , 22 . Vias 40 have a diameter of about the technology node, that is about 90 to 150 nm, typically about 130 nm for a technology node having a minimum lithographic feature size of 0.13 microns.
[0033] A thermal insulator 42 is formed within each via 40 , using a conformal deposition process such as chemical vapor deposition (CVD). Thermal insulator 42 is a better thermal insulator than the material of inter-electrode layer 38 , preferably at least 10 % better. Therefore, thermal insulator 42 has a thermal conductivity value kappa of less than 0.014 J/cm/K/sec. Representative materials for thermal insulator 42 include materials that are a combination of the elements silicon Si, carbon C, oxygen O, fluorine F, and hydrogen H. Examples of thermally insulating materials which have a thermal insulation value kappa of greater than 0.014 J/cm/°K/sec. and are candidates for use as thermal insulator 42 include SiCOH, polyimide, polyamide, and fluorocarbon polymers. Other examples of materials which are candidates for use for thermal insulator 42 include fluorinated SiO 2 , silsesquioxane, polyarylene ethers, parylene, fluoro-polymers, fluorinated amorphous carbon, diamond like carbon, porous silica, mesoporous silica, porous silsesquioxane, porous polyimide, and porous polyarylene ethers. In other embodiments, the thermally insulating structure comprises a gas-filled void lining the walls of via 40 . A single layer or combination of layers can provide thermal insulation.
[0034] Thermal insulator 42 is preferably formed as sidewall stucture to create the generally conical, downwardly and inwardly tapering central open region 44 shown in FIG. 6 . Open region 44 could have other constricting shapes, such as an hourglass shape, a reverse conical shape or a staircase or otherwise stepped shape. It may also be possible to make open region with a constant, appropriately small cross-sectional size and thus without a constricted area. The shape of open region 44 may be the result of the deposition process chosen for the deposition of thermal insulator 42 ; the deposition of thermal insulator 42 may also be controlled to result in the desired, typically constricting, shape for open region 44 . Processing steps may be also undertaken after deposition of thermal insulator 42 to create the desired shape for open region 44 . FIG. 7 illustrates a result of depositing a phase change material 46 within central open region 44 , followed by chemical mechanical polishing to create a surface 47 . Phase change material 46 is thermally insulated from layer 38 by thermal insulator 42 . The downwardly and inwardly tapering shape of thermal insulator 42 creates a narrow transition region 48 of change material 46 to create a phase change element 49 at region 48 . Phase change material 46 is typically about 130 nm wide at surface 47 and about 30 to 70 nm, typically about 50 nm, at transition region 48 .
[0035] Both the smaller size of phase change element 49 at transition region 48 and the use of thermal insulator 42 reduce the current needed to cause a change between a lower resistivity, generally crystalline state and a higher resistivity, generally amorphous state for phase change element 49 .
[0036] FIG. 8 illustrates the results of TiN deposition and chemical mechanical polishing to create a second electrode layer 50 having a planarized surface 52 . Lithographic mask 54 is shown in FIG. 9 positioned overlying first and second plugs 20 , 22 and their associated thermal insulators 42 and phase change materials 46 . FIG. 10 illustrates the results of etching steps in which portions of second electrode layer 50 , silicon dioxide layer 38 and first electrode layer 34 not covered by mask 54 are removed using appropriate etching recipes according to the composition of the layers to create etched regions 56 and first and second electrodes 57 , 59 . Lithographic mask 54 is sized so that portions 61 of inter-electrode layer 38 are left surrounding thermal insulators 42 after the etching steps of FIG. 10 to prevent etching of thermal insulator 42 , which could be caused by conventional tolerances associated with conventional manufacturing steps.
[0037] FIG. 11 illustrates the results of an oxide fill-in step in which an fill 58 , such as silicon dioxide, is deposited within etched regions 56 , reconstituting the inter-electrode layer 48 and filling between the memory cells, and followed by CMP to create planarized surface 60 . Thereafter, an electrically conductive material 62 is deposited on surface 60 to create phase change memory device 10 , including memory cells 64 , shown in FIG. 1 . Electrically conductive material 62 is typically copper or aluminum, but it also may be tungsten, titanium nitride or other materials and combinations of materials.
[0038] Electrodes 57 , 59 in the illustrated embodiments are preferably TiN. Although other materials, such as TaN, TiAlN or TaAlN, may be used for electrodes 57 , 59 , TiN is presently preferred because it makes good contact with GST (discussed below) as phase change material 46 , it is a common material used in semiconductor manufacturing, and it provides a good diffusion barrier at the higher temperatures at which phase change material 46 transitions, typically in the 600-700° C. range. Plugs 20 , 22 and common source line 24 are typically made of tungsten.
[0039] Embodiments of the memory cell include phase change based memory materials, including chalcogenide based materials and other materials, for phase change material 46 . Chalcogens include any of the four elements oxygen (O), sulfur (S), selenium (Se), and tellurium (Te), forming part of group VI of the periodic table. Chalcogenides comprise compounds of a chalcogen with a more electropositive element or radical. Chalcogenide alloys comprise combinations of chalcogenides with other materials such as transition metals. A chalcogenide alloy usually contains one or more elements from column six of the periodic table of elements, such as germanium (Ge) and tin (Sn). Often, chalcogenide alloys include combinations including one or more of antimony (Sb), gallium (Ga), indium (In), and silver (Ag). Many phase change based memory materials have been described in technical literature, including alloys of: Ga/Sb, In/Sb, In/Se, Sb/Te, Ge/Te, Ge/Sb/Te, In/Sb/Te, Ga/Se/Te, Sn/Sb/Te, In/Sb/Ge, Ag/In/Sb/Te, Ge/Sn/Sb/Te, Ge/Sb/Se/Te and Te/Ge/Sb/S. In the family of Ge/Sb/Te alloys, a wide range of alloy compositions may be workable. The compositions can be characterized as TeaGebSb100-(a+b).
[0040] One researcher has described the most useful alloys as having an average concentration of Te in the deposited materials well below 70%, typically below about 60% and ranged in general from as low as about 23% up to about 58% Te and most preferably about 48% to 58% Te. Concentrations of Ge were above about 5% and ranged from a low of about 8% to about 30% average in the material, remaining generally below 50%. Most preferably, concentrations of Ge ranged from about 8% to about 40%. The remainder of the principal constituent elements in this composition was Sb. These percentages are atomic percentages that total 100% of the atoms of the constituent elements. (Ovshinsky '112 patent, columns 10-11.) Particular alloys evaluated by another researcher include Ge 2 Sb 2 Te 5 , GeSb 2 Te 4 and GeSb 4 Te 7 . (Noboru Yamada, “Potential of Ge—Sb—Te Phase-Change Optical Disks for High-Data-Rate Recording” , SPIE v. 3109, pp. 28-37 (1997).) More generally, a transition metal such as chromium (Cr), iron (Fe), nickel (Ni), niobium (Nb), palladium (Pd), platinum (Pt) and mixtures or alloys thereof may be combined with Ge/Sb/Te to form a phase change alloy that has programmable resistive properties. Specific examples of memory materials that may be useful are given in Ovshinsky '112 at columns 11-13, which examples are hereby incorporated by reference.
[0041] Phase change alloys are capable of being switched between a first structural state in which the material is in a generally amorphous solid phase, and a second structural state in which the material is in a generally crystalline solid phase in its local order in the active channel region of the cell. These alloys are at least bistable. The term amorphous is used to refer to a relatively less ordered structure, more disordered than a single crystal, which has the detectable characteristics such as higher electrical resistivity than the crystalline phase. The term crystalline is used to refer to a relatively more ordered structure, more ordered than in an amorphous structure, which has detectable characteristics such as lower electrical resistivity than the amorphous phase. Typically, phase change materials may be electrically switched between different detectable states of local order across the spectrum between completely amorphous and completely crystalline states. Other material characteristics affected by the change between amorphous and crystalline phases include atomic order, free electron density and activation energy. The material may be switched either into different solid phases or into mixtures of two or more solid phases, providing a gray scale between completely amorphous and completely crystalline states. The electrical properties in the material may vary accordingly.
[0042] Phase change alloys can be changed from one phase state to another by application of electrical pulses. It has been observed that a shorter, higher amplitude pulse tends to change the phase change material to a generally amorphous state. A longer, lower amplitude pulse tends to change the phase change material to a generally crystalline state. The energy in a shorter, higher amplitude pulse is high enough to allow for bonds of the crystalline structure to be broken and short enough to prevent the atoms from realigning into a crystalline state. Appropriate profiles for pulses can be determined, without undue experimentation, specifically adapted to a particular phase change alloy. A material useful for implementation of a PCRAM described herein is Ge 2 Sb 2 Te 5 , commonly referred to as GST. Other types of phase change materials can also be used.
[0043] Other programmable resistive materials may be used in other embodiments of the invention, including N 2 doped GST, Ge x Sb y , or other material that uses different crystal phase changes to determine resistance; Pr x Ca y MnO 3 , PrSrMnO, ZrOx, or other material that uses an electrical pulse to change the resistance state; 7,7,8,8-tetracyanoquinodimethane (TCNQ), methanofullerene 6,6-phenyl C61-butyric acid methyl ester (PCBM), TCNQ-PCBM, Cu-TCNQ, Ag-TCNQ, C60-TCNQ, TCNQ doped with other metal, or any other polymer material that has bistable or multi-stable resistance state controlled by an electrical pulse. For example, another type of memory material that in some situations may be appropriate is a variable resistance ultra thin oxide layer.
[0044] For additional information on the manufacture, component materials, use and operation of phase change random access memory devices, see U.S. patent application Ser. No. 11/155,067, filed 17 Jun. 2005, entitled Thin Film Fuse Phase Change Ram And Manufacturing Method, Attorney Docket No. MXIC 1621-1.
[0045] The invention has been described with reference to phase change materials. However, other memory materials, also sometimes referred to as programmable materials, can also be used. As used in this application, memory materials are those materials having electrical properties that can be changed by the application of energy; the change can be a stepwise change or a continuous change or a combination thereof.
[0046] The above descriptions may have used terms such as above, below, top, bottom, over, under, et cetera. These terms are used to aid understanding of the invention are not used in a limiting sense.
[0047] While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is to be understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the following claims.
[0048] Any and all patents, patent applications and printed publications referred to above are hereby incorporated by reference.
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A thermally insulated memory device comprises a memory cell, the memory cell having electrodes with a via extending therebetween, a thermal insulator within the via and defining a void extending between the electrode surfaces. A memory material, such as a phase change material, is within the void and electrically couples the electrodes to create a memory material element. The thermal insulator helps to reduce the power required to operate the memory material element. An electrode may contact the outer surface of a plug to accommodate any imperfections, such as the void-type imperfections, at the plug surface. Methods for making the device and accommodating plug surface imperfections are also disclosed.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based, and claims priority under 35 U.S.C. § 120 to U.S. Provisional Patent Application No. 60/991,003 filed on Nov. 29, 2007, and which is incorporated herein by reference.
DESCRIPTION OF THE INVENTION
[0002] Ocular hypotensive agents are useful in the treatment of a number of various ocular hypertensive conditions, such as post-surgical and post-laser trabeculectomy ocular hypertensive episodes, glaucoma, and as presurgical adjuncts.
[0003] Glaucoma is a disease of the eye characterized by increased intraocular pressure. On the basis of its etiology, glaucoma has been classified as primary or secondary. For example, primary glaucoma in adults (congenital glaucoma) may be either open-angle or acute or chronic angle-closure. Secondary glaucoma results from pre-existing ocular diseases such as uveitis, intraocular tumor or an enlarged cataract. Glaucoma occurs in about 2% of all persons over the age of 40 and may be asymptotic for years before progressing to rapid loss of vision.
[0004] The underlying causes of primary glaucoma are not yet known. The increased intraocular tension is due to the obstruction of aqueous humor outflow. In chronic open-angle glaucoma, the anterior chamber and its anatomic structures appear normal, but drainage of the aqueous humor is impeded. In acute or chronic angle-closure glaucoma, the anterior chamber is shallow, the filtration angle is narrowed, and the iris may obstruct the trabecular meshwork at the entrance of the canal of Schlemm. Dilation of the pupil may push the root of the iris forward against the angle, and may produce pupilary block and thus precipitate an acute attack. Eyes with narrow anterior chamber angles are predisposed to acute angle-closure glaucoma attacks of various degrees of severity.
[0005] Secondary glaucoma is caused by any interference with the flow of aqueous humor from the posterior chamber into the anterior chamber and subsequently, into the canal of Schlemm. Inflammatory disease of the anterior segment may prevent aqueous escape by causing complete posterior synechia in iris bombe, and may plug the drainage channel with exudates. Other common causes are intraocular tumors, enlarged cataracts, central retinal vein occlusion, trauma to the eye, operative procedures and intraocular hemorrhage.
[0006] In cases where surgery is not indicated, prostaglandins and prostamides have recently become the first line treatments of glaucoma. Certain eicosanoids and their derivatives are currently commercially available for use in glaucoma management. Eicosanoids and derivatives include numerous biologically important compounds such as prostaglandins and their derivatives. Prostaglandins can be described as derivatives of prostanoic acid which have the following structural formula:
[0000]
[0007] Various types of prostaglandins are known, depending on the structure and substituents carried on the alicyclic ring of the prostanoic acid skeleton. Further classification is based on the number of unsaturated bonds in the side chain indicated by numerical subscripts after the generic type of prostaglandin [e.g. prostaglandin E 1 (PGE 1 ), prostaglandin E 2 (PGE 2 )], and on the configuration of the substituents on the alicyclic ring indicated by α or β [e.g. prostaglandin F 2α (PGF 2β )].
[0008] Disclosed herein are compounds represented by the formula:
[0000]
[0000] wherein a dashed line represents the presence or absence of a bond;
Y has from 0 to 14 carbon atoms and is: an organic acid functional group, or an amide or ester thereof; hydroxymethyl or an ether thereof; or a tetrazolyl functional group;
A is a 6 atom interarylated linear alkyl, ethereal, or thioethereal chain;
X is halo, ═O, —OH, ═S, —SH, —CF 3 , —CN, ═CH 2 , ═CHalkyl or ═C(alkyl) 2 having from 1 to 6 carbon atoms;
Z is halo, —OH, —OR, —SH, —CF 3 , or —CN; and
each R is independently —H, C 1-6 alkyl, C 1-6 hydroxyalkyl, or C 1-6 acyl.
[0009] These compounds are useful for reducing intraocular pressure. Reduction of intraocular pressure has been shown to delay or prevent the onset of primary open angle glaucoma, and to delay or prevent further vision loss in patients with primary open angle glaucoma. Thus, these compounds are also useful for treating glaucoma. Different types of suitable dosage forms and medicaments are well known in the art, and can be readily adapted for delivery of the compounds disclosed herein. For example, the compound could be dissolved or suspended in an aqueous solution or emulsion that is buffered to an appropriate pH, and administered topically to an eye of a mammal (see U.S. Pat. No. 7,091,231).
[0010] One embodiment is a method of reducing intraocular pressure comprising administering a compound disclosed herein to a mammal in need thereof.
[0011] Another embodiment is use of a compound disclosed herein in the manufacture of a medicament for the treatment of glaucoma.
[0012] An ophthalmically acceptable liquid comprising a compound disclosed herein and an ophthalmically acceptable excipient.
[0013] For the purposes of this disclosure, “treat,” “treating,” or “treatment” refers to the diagnosis, cure, mitigation, treatment, or prevention of disease or other undesirable condition.
[0014] Unless otherwise indicated, reference to a compound should be construed broadly to include pharmaceutically acceptable salts, prodrugs, tautomers, alternate solid forms, non-covalent complexes, and combinations thereof, of a chemical entity of a depicted structural formula or chemical name.
[0015] A pharmaceutically acceptable salt is any salt of the parent compound that is suitable for administration to an animal or human. A pharmaceutically acceptable salt also refers to any salt which may form in vivo as a result of administration of an acid, another salt, or a prodrug which is converted into an acid or salt. A salt comprises one or more ionic forms of the compound, such as a conjugate acid or base, associated with one or more corresponding counter-ions. Salts can form from or incorporate one or more deprotonated acidic groups (e.g. carboxylic acids), one or more protonated basic groups (e.g. amines), or both (e.g. zwitterions).
[0016] A prodrug is a compound which is converted to a therapeutically active compound after administration. For example, conversion may occur by hydrolysis of an ester group or some other biologically labile group. Prodrug preparation is well known in the art. For example, “Prodrugs and Drug Delivery Systems,” which is a chapter in Richard B. Silverman, Organic Chemistry of Drug Design and Drug Action, 2d Ed., Elsevier Academic Press: Amsterdam, 2004, pp. 496-557, provides further detail on the subject. In particular, alkyl esters having such as methyl, ethyl, isopropyl, and the like are contemplated. Also contemplated are prodrugs containing a polar group such as hydroxyl or morpholine. Examples of such prodrugs include compounds containing the moieties —CO 2 (CH 2 ) 2 OH,
[0000]
[0000] and the like. Thus, compounds represented by the formula below are examples of useful prodrugs.
[0000]
[0017] Tautomers are isomers that are in rapid equilibrium with one another. For example, tautomers may be related by transfer of a proton, hydrogen atom, or hydride ion.
[0018] Unless stereochemistry is explicitly and unambiguously depicted, a structure is intended to include every possible stereoisomer, both pure or in any possible mixture.
[0019] Alternate solid forms are different solid forms than those that may result from practicing the procedures described herein. For example, alternate solid forms may be polymorphs, different kinds of amorphous solid forms, glasses, and the like.
[0020] Non-covalent complexes are complexes that may form between the compound and one or more additional chemical species that do not involve a covalent bonding interaction between the compound and the additional chemical species. They may or may not have a specific ratio between the compound and the additional chemical species. Examples might include solvates, hydrates, charge transfer complexes, and the like.
[0021] Y is an organic acid functional group, or an amide or ester thereof; or Y is hydroxymethyl or an ether thereof; or Y is a tetrazolyl functional group. For the purposes of this disclosure, Y is limited to from 0 to 14 carbon atoms, from 0 to 5 oxygen atoms, from 0 to 2 nitrogen atoms, from 0 to 2 sulfur atoms, from 0 to 1 phosphorous, and any necessary hydrogen atoms.
[0022] An organic acid functional group is an acidic functional group on an organic molecule. While not intending to be limiting, organic acid functional groups may comprise an oxide of carbon, sulfur, or phosphorous. Thus, while not intending to limit the scope of the invention in any way, in certain compounds Y is a carboxylic acid, sulfonic acid, or phosphonic acid functional group.
[0023] Esters and amides of organic functional groups are carbonyl groups directly attached to a nitrogen or oxygen atom. Thus, esters of amides of carboxylic acids, sulfonic acid, and phosphonic acid functional groups are depicted below.
[0000]
[0024] An amide may also have an —SO 2 — moiety. For example the amide —CONHSO 2 R 3 , wherein R 3 is a hydrocarbyl of from 1 to 14 carbon atoms, is contemplated. R, R 1 , R 2 , and R 3 are hydrocarbyl subject to the constraint that Y may not have more than 14 carbon atoms.
[0025] Hydrocarbyl is a moiety consisting of carbon and hydrogen, including, but not limited to:
a. alkyl, which is hydrocarbyl that contains no double or triple bonds, such as:
linear alkyl, e.g. methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, etc., branched alkyl, e.g. iso-propyl, t-butyl and other branched butyl isomers, branched pentyl isomers, etc., cycloalkyl, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc., combinations of linear, branched, and/or cycloalkyl;
b. alkenyl, which is hydrocarbyl having 1 or more double bonds, including linear, branched, or cycloalkenyl; c. alkynyl, which is hydrocarbyl having 1 or more triple bonds, including linear, branched, or cycloalkynyl; d. unsubstituted or hydrocarbyl substituted phenyl; and e. combinations of alkyl, alkenyl, and/or alkynyl
[0035] C 1-6 hydrocarbyl is hydrocarbyl having 1, 2, 3, 4, 5, or 6 carbon atoms.
[0036] C 1-6 alkyl is alkyl having 1, 2, 3, 4, 5, or 6, carbon atoms such as methyl, ethyl, propyl isomers, butyl isomers, pentyl isomer, and hexyl isomers, etc.
[0037] An unsubstituted tetrazolyl functional group has two tautomeric forms, which can rapidly interconvert in aqueous or biological media, and are thus equivalent to one another. These tautomers are shown below.
[0000]
[0038] Additionally, if R 2 is C 1 -C 6 alkyl, phenyl, or biphenyl, other isomeric forms of the tetrazolyl functional group such as the one shown below are also possible, unsubstituted and hydrocarbyl substituted tetrazolyl up to C 14 are considered to be within the scope of the term “tetrazolyl.”
[0000]
[0039] In one embodiment, Y is —CO 2 R 4 , —CONR 5 R 6 , —CON(CH 2 CH 2 OH) 2 , —CONH(CH 2 CH 2 OH), —CH 2 OH, —P(O)(OH) 2 , —CONHSO 2 R 4 , —SO 2 NR 5 R 6 ,
[0000]
[0000] wherein R 4 , R 5 and R 6 are independently H, C 1 -C 6 alkyl, C 1-6 hydroxyalkyl, unsubstituted phenyl, or unsubstituted biphenyl, provided that Y has no more than 14 carbon atoms.
[0040] A is a 6 atom interarylated linear alkyl, ethereal, or thioethereal chain. In other words, A consists of one or two linear alkyl, linear ethereal, or linear thioethereal fragments (L) and an interarylene moiety (Ar) forming a structure -L-Ar-L-, —Ar-L-, or -L-Ar—. The atoms of the one or two L groups and 2, 3, or 4 atoms from Ar, form a 6 atom chain connecting the substituted cyclopentyl of the structure with Y. Thus, A may have one of the basic structures below, wherein:
a. the linear portions (L) may have —O— or —S— in place of one or more carbon atoms; b. the rings may be substituted; c. the rings may have one or more nitrogen atoms in place of a CH; and d. Q is —S—, —O—, or —NH—.
[0000]
[0045] Thus, since Q is —S—, —O—, or —NH—, and the rings may have one or more nitrogen atoms in place of a CH, the ring may be, for example, pyridinyl, pyrazinyl, imidazole, thiazole, oxazole, and the like, both substituted and unsubstituted.
[0046] A linear ethereal fragment is —O-alkyl, -alkyl-O—, -alkyl-O-alkyl- or —O—CH 2 CH 2 —O—, where alkyl is linear.
[0047] A linear thioethereal fragment is —S-alkyl, -alkyl-S—, -alkyl-5-alkyl- or —S—CH 2 CH 2 —S—, where alkyl is linear.
[0048] Interarylene is aryl which connects two other parts of the molecule, i.e. L- and -L, L- and —Y, or the cyclopentyl and -L. The interarylene moiety may have substituents in addition to the 2 connecting it to the rest of the molecule. There may be as many of these substituents as the ring will bear, and if they are present they are selected from alkyl, alkoxy, acyl, acyloxy, —S-alkyl, or amino (i.e. —NH 2 , —NHalkyl, —N(alkyl) 2 ) having from 1-4 carbon atoms, halo (—F, —Cl, —Br, —I), —CN, or —CO 2 H.
[0049] X is halo, ═O, —OH, ═S, —SH, —CF 3 , —CN, ═CH 2 , ═CHalkyl or ═C(alkyl) 2 having from 1 to 6 carbon atoms. The alkyl moieties of ═C(alkyl) 2 are independent, i.e. they may be the same or different. Thus, for example, X may be one of the groups depicted below.
[0000]
[0050] In one embodiment X is halo.
[0051] In another embodiment X is —F.
[0052] In another embodiment X is —Cl.
[0053] In another embodiment X is —Br.
[0054] In another embodiment X is —I.
[0055] In another embodiment, X is ═O. For example, the compound may have a structure shown below.
[0000]
[0056] In another embodiment X is —OH.
[0057] In another embodiment X is ═S.
[0058] In another embodiment X is —SH.
[0059] In another embodiment X is —CF 3 .
[0060] In another embodiment X is —CN.
[0061] In another embodiment X is ═CH 2 .
[0062] In another embodiment X is ═CHalkyl.
[0063] In another embodiment X is ═C(alkyl) 2 .
[0064] In one embodiment Z is halo.
[0065] In another embodiment Z is —F.
[0066] In another embodiment Z is —Cl.
[0067] In another embodiment Z is —Br.
[0068] In another embodiment Z is —I.
[0069] In another embodiment Z is —OH.
[0070] In another embodiment Z is —OR.
[0071] In another embodiment Z is —SH.
[0072] In another embodiment Z is —CF 3 .
[0073] In another embodiment Z is —CN.
[0074] Each R is independently —H, C 1-6 alkyl, C 1-6 hydroxyalkyl, or C 1-6 acyl.
[0075] Hydroxyalkyl is -alkyl-OH, C 1-6 hydroxyalkyl is hydroxyalkyl having from 1-6 carbon atoms. Examples include hydroxymethyl, hydroxyethyl, etc.
[0076] Acyl is
[0000]
[0000] C 1-6 acyl is acyl having from 1 to 6 carbon atoms.
[0077] One embodiment is a compound represented by the formula:
[0000]
[0078] Another embodiment is a compound represented by the formula:
[0000]
[0079] In another embodiment, R is C 1-6 alkyl in the structure above.
[0080] In another embodiment, R is C 1-6 hydroxyalkyl in the structure above.
[0081] In another embodiment, R is C 1-6 acyl in the structure above.
[0082] Another embodiment is a compound represented by the formula:
[0000]
[0083] In another embodiment, R is C 1-6 alkyl in the structure above.
[0084] In another embodiment, R is C 1-6 hydroxyalkyl in the structure above.
[0085] In another embodiment, R is C 1-6 acyl in the structure above.
[0086] Another embodiment is a compound represented by the formula:
[0000]
[0087] In another embodiment, R is C 1-6 alkyl in the structure above.
[0088] In another embodiment, R is C 1-6 hydroxyalkyl in the structure above.
[0089] In another embodiment, R is C 1-6 acyl in the structure above.
[0090] Another embodiment is a compound represented by the formula:
[0000]
[0091] Hypothetical examples of useful compounds are depicted below.
[0000]
[0092] Another embodiment is a compound represented by the formula:
[0000]
[0000] wherein L 1 is —(CH 3 ) 3 —, —O(CH 2 ) 2 —, —CH 2 OCH 2 —, —(CH 2 ) 2 O—;
T is ═CH— or ═N—;
[0093] provided that L 1 and Y have a 1,3 relationship to one another.
[0094] A 1,3 relationship between L1 and Y means that the two groups are bonded to two ring carbon atoms having one ring atom between them. For example, meta substituents on phenyl have a 1, 3 relationship. The structure depicted in the embodiment below also has a 1,3-relationship between L 1 and Y, where the S is the one ring atom between the two carbons attached to L 1 and Y.
[0095] Another embodiment is a compound represented by the formula:
[0000]
[0096] Another embodiment is a compound represented by the structure above wherein X is F, Cl, ═O, or OH.
[0097] Another embodiment is a compound represented by the structure above wherein Z is OH.
[0098] Another embodiment is a compound represented by the structure above wherein Y is —CO 2 H or an ester or amide thereof.
[0099] Another embodiment is a compound represented by the formula:
[0000]
[0100] Another embodiment is a compound represented by the formula:
[0000]
SYNTHETIC METHODS
[0101] While there are many ways to prepare the compounds disclosed herein, useful compounds may be obtained by using or adapting the following exemplary procedures.
[0000]
(S)-Methyl CBS-borane Reagent (2)
[0102] A 250 mL, 2 neck Schlenk flask was equipped with a magnetic stirbar, a N 2 inlet, and charged with 75 mL of (S)-methyloxazaborolidine 1 in toluene (1.0 M) at 20° C. Approximately half the volume of toluene was evaporated under vacuum with mild warming to yield about 40 mL of 2 M oxazaborolidine. Borane-dimethyl sulfide complex (10 mL, 10 M, neat) was added in one portion with rapid stirring and the resulting solution was stirred for 30 min at 20° C. Pentane (200 mL) was then added via cannula to precipitate the product (after 15 min of stirring), followed by filtration under N 2 and the solids were washed with 2 additional 200 mL portions of pentane. The solids were dried under a stream of nitrogen to a constant weight, affording 19.4 g (88% yield) of borane complex 2 as a white solid. The purity was estimated >90% by NMR analysis 1 H NMR (CDCl 3 ): 0.73 (s, 3H), 1.29 (m, 2H), 1.57 (m, 2H), 1.90 (m, 2H), 3.18 (dt, 1H), 3.37 (m, 1H), 4.61 (t, 1H), 7.2-7.6 (m, 10H).
[0103] The corresponding (R)-Methyl CBS-borane reagent was prepared in the same manner starting with the (R)-methyloxazaborolidine.
Ethyl 5(R)-hydroxyhexanoate (3)
[0104] A 250 mL, round bottom flask was equipped with a magnetic stirrer, a N 2 inlet, a type-J teflon covered thermocouple, and charged with 6 g of (S)-methyl-CBS-borane complex 2 (20.6 mmol) dissolved in 40 mL of dichloromethane (DCM). The solution was cooled to −40° C. before ethyl 4-acetylbutyrate (3 g, 18.9 mmol) in 5 mL of DCM was added dropwise at a rate which kept the internal temperature below −20° C. At the end of addition, the dry ice/isopropanol cooling bath was substituted with an ice bath maintaining the internal reaction temperature at 0° C. for an additional hour. G.C. analysis showed less than 5% starting ketone. The reaction was worked up after 2 h at 0° C. by cautious addition of saturated aqueous ammonium chloride (100 mL). The mixture was transferred to a separatory funnel and extracted with ethyl acetate (2×100 mL). The separated combined organic extracts were washed with brine and dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo to yield 7 g of crude products. Flash column chromatography (FCC) on 120 g of flash grade silica gel eluting with 20% EtOAc-hexanes yielded 1.94 g (65%) of alcohol 3 as an oil. G.C. analysis indicated a purity of 97.4A %. 1 H NMR (CDCl 3 ): 1.20 (d, J=3 Hz, 3H), 1.26 (t, J=7.2 Hz, 3H), 1.47 (m, 2H), 1.71 (m, 3H), 2.34 (t, J=7.5 Hz, 2H), 3.89 (m, 1H), 4.13 (q, J=7.2 Hz, 2H).
Ethyl 5(R)-t-butyldimethylsilyloxyhexanoate (4)
[0105] A solution of ethyl 5(R)-hydroxyhexanoate 3 (1.80 g, 11.24 mmol), imidazole (2.3 g, 33.8 mmol), and t-butyldimethylsilyl chloride (2.54 g, 16.85 mmol) in 30 mL of DMF was stirred at 23° C. overnight (19 h). The solvent (DMF) was then removed in vacuo and aqueous saturated sodium bicarbonate (100 mL) was added followed by ethyl acetate (100 mL). The layers were separated and the aqueous layer was re-extracted with 100 mL of EtOAc. The combined organic layers were washed with water, brine, and dried over anhydrous sodium sulfate. Flash column chromatographic purification on 30 g of silica gel yielded 2.71 g (88%) of TBDMS-ether 4 (G.C. purity of 99+A %); 1 H NMR (CDCl 3 ): 0.04 (s, 6H), 0.91 (s, 9H), 1.18 (d, J=6 Hz, 3H), 1.25 (t, J=7.2 Hz, 3H), 1.42 (m, 2H), 1.65 (m, 2H), 2.39 (t, J=7.5 Hz, 2H), 3.79 (m, J=6 Hz, 1H), 4.12 (q, J=7.2 Hz, 2H).
Dimethyl 6(R)-6-{[t-butyl(dimethyl)silyl]oxy}-2-oxoheptylphosphonate (5)
[0106] To a solution of dimethyl methylphosphonate (2.12 mL, 19.6 mmol) in 25 mL of THF at −78° C. was added butyllithium in hexanes (13.5 mL of a 1.6 M solution in hexanes, 21.6 mmol). The mixture was stirred under nitrogen at this temperature for 30 minutes before a solution of ethyl 5(R)-t-butyldimethylsilyloxyhexanoate 4 (2.7 g, 9.8 mmol) in 8 mL of THF was added dropwise. The mixture was stirred overnight during which the temperature was allowed to warm to room temperature of 25° C. The reaction was sampled by TLC after 18 h (R f of product was 0.6 in ethyl acetate) and worked up by addition of saturated aqueous ammonium chloride (100 mL). The product was extracted from the aqueous layer with ethyl acetate and washed with brine. The combined ethyl acetate extracts were dried over anhydrous sodium sulfate and concentrated to yield 3.7 g of crude products. Flash column chromatographic purification on 120 g of silica gel eluted with 3:1 ethyl acetate:hexanes yielded 2.65 g (76% yield) of purified phosphonate 5 as a clear oil; 1 H NMR (CDCl 3 ): 0.04 (s, 6H), 0.88 (s, 9H), 1.11 (d, J=6 Hz, 3H), 1.30-1.75 (m, 4H), 2.62 (t, J=7.2 Hz, 2H), 3.08 (d, J=22.5 Hz, 2H), 3.77 (s, 3H), 3.80 (s, 3H).
[0000]
Methyl 5-(3-((1R,2R,3R,5R)-5-chloro-2-formyl-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)propyl)thiophene-2-carboxylate (7)
[0107] A solution of 330 mg of alcohol 6 (0.79 mmol) in 2 mL of dichloromethane was added via pipette to a mixture of PCC (400 mg, 1.86 mmol), sodium acetate (150 mg, 1.83 mmol), and Celite (600 mg) in 5 mL of DCM. The pipette was rinsed with an additional 3 mL of DCM to complete the transfer. The mixture was stirred sealed in a 30° C. water bath for 1.5 h. The mixture was worked up by filtration through 10 g of silica gel and washed with 100 mL of 1:1 EA:hexanes. The filtrate was concentrated in vacuo to yield the crude aldehyde as an oil. The crude product was purified by preparative thin layer chromatography (2×2 mm thick plates, eluted in 1:1 hexanes:EtOAc), to yield 238 mg (72%) of aldehyde 7; 1 H NMR (CDCl 3 ): 1.53 (br m, 6H), 1.6-1.85 (m, 5H), 2.05-2.72 (m, 4H), 2.87 (t, J=6.3 Hz, 2H), 3.49 (m, 1H), 3.80 (m, 1H), 3.86 (s, 3H), 4.05 (m, 1H), 4.55 (m, 1H), 4.63 (m, 1H), 6.79 (d, J=3.9 Hz, 1H), 7.63 (d, J=3.9 Hz, 1H), 9.78 (dd, J=10.8 and 1.8 Hz, 1H).
Methyl 5-(3-((1R,2R,3R,5R)-2-((R,E)-7-(tert-butyldimethylsilyloxy)-3-oxooct-1-enyl)-5-chloro-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)propyl)thiophene-2-carboxylate (8)
[0108] To a suspension of 54 mg of sodium hydride (60% oil dispersion, 1.35 mmol) in 1 ml of THF at 0° C. was added a solution of dimethyl (6R)-6-{[tert-butyl(dimethyl)silyl]oxy}-2-oxoheptylphosphonate 5 (552 mg, 1.57 mmol) in 1 mL THF. The mixture was stirred at 0° C. for 30 min before a solution of aldehyde 7 (460 mg, 1.1 mmol) in 1 ml of THF was added dropwise. The syringe containing the aldehyde was rinsed with 2 mL of THF to complete the addition and the mixture was stirred at 25° C. for 2.5 h. The reaction was worked up with addition of saturated aqueous ammonium chloride (50 mL) and the aqueous layer was extracted with ethyl acetate (2×75 mL). The ethyl acetate layers were combined and washed with brine, dried over 30 g of anhydrous sodium sulfate, filtered and concentrated in vacuo to yield 920 mg of crude products. Flash chromatographic purification using a 24 g silica gel cartridge eluted with 10% EtOAc-hexanes yielded 430 mg (60%) of purified enone 8; 1 H NMR (CDCl 3 ): 0.05 (s, 6H), 0.88 (s, 9H), 1.12 (d, J=6.3 Hz, 3H), 1.37-1.80 (m, 14H), 2.00 (m, 1H), 2.20 (m, 1H), 2.34 (m, 1H), 2.53 (m, 1H), 2.54 (t, J=7.2 Hz, 2H), 2.83 (m, 2H), 3.45 (m, 1H), 3.80 (m, 2H), 3.86 (s, 3H), 4.02 (m, 1H), 4.17 (m, 1H), 4.57 (m, 1H), 6.15 (m, 1H), 6.77 (m, 1H), 7.62 (d, J=3.9 Hz).
Methyl 5-(3-((1R,2R,3R,5R)-2-((3S,7R,E)-7-(tert-butyldimethylsilyloxy)-3-hydroxyoct-1-enyl)-5-chloro-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)-propyl)thiophene-2-carboxylate (9)
[0109] A solution of enone 8 (400 mg, 0.62 mmol) in 7 mL of dichloromethane was cooled to −20° C. and stirred rapidly while solid (R)-methylCBS-borane complex 2 (290 mg, 1.0 mmol), was added in one portion. The resulting solution was stirred at −20° to −10° C. for 1 h. TLC analysis at this stage showed no starting material left and the reaction mixture was quenched with 1 mL of methanol, the cooling bath was removed and the mixture was stirred at 20° C. 30 min. The mixture was concentrated in vacuo to remove solvents and the residual products were purified by FCC on silica gel (40 g Silicycle cartridge) to yield 40 mg of (15R+S) isomers and 325 mg of (15S)-alcohol 9; 1 H NMR (CDCl 3 ): 0.03 (s, 6H), 0.87 (s, 9H), 1.09 (d, J=6.3 Hz, 3H), 1.30-1.90 (m, 18H), 2.05-2.35 (m, 3H), 2.82 (m, 2H), 3.45 (m, 1H), 3.76 (m, 2H), 3.84 (s, 3H), 3.97 (m, 1H), 4.07 (m, 2H), 4.60 (dt, J=4.2 Hz, 11.1 Hz, 1H), 5.57 (m, 2H), 6.77 (d, J=3.9 Hz, 1H), 7.61 (d, J=3.9 Hz, 1H).
Methyl 5-(3-((1R,2R,3R,5R)-5-chloro-2-((3S,7R,E)-3,7-dihydroxyoct-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)propyl)thiophene-2-carboxylate (10)
[0110] A solution of silyl ether 9 (325 mg, 0.51 mmol) in 1 mL of THF was stirred at 30° C. with 2 mL of 1.0M TBAF/THF in a vial for 7.5 h. TLC indicated starting material was mostly desilylated and the reaction was concentrated in vacuo. The residual crude products were taken up in 50 mL of ethyl acetate and washed sequentially with saturated aqueous ammonium chloride (50 mL), brine (50 mL), and dried over 10 g of anhydrous sodium sulfate. The mixture was filtered and concentrated in vacuo. The residual products were purified by preparative layer chromatography on 2×2 mm thick silica gel plates eluted in EtOAc (Rf=0.5). Extraction of the major band yielded 214 mg (80%) of pure diol 10 as an oil; 1 H NMR (CDCl 3 ): 1.18 (d, J=6 Hz, 3H), 1.38-1.68 (m, 11H), 1.66-2.37 (m, 9H), 2.84 (t, J=7.2 Hz, 2H), 3.47 (m, 1H), 3.79 (m, 1H), 3.86 (s, 3H), 3.98 (p, J=7.5 Hz, 1H), 4.09 (m, 2H), 4.63 (dt, J=3, 27 Hz, 2H), 5.58 (m, 2H), 6.78 (dd, J=0.6, 3.6 Hz, 1H), 7.62 (d, J=3.6 Hz, 1H).
Methyl 5-(3-((1R,2R,3R,5R)-5-chloro-2-((3S,7R,E)-3,7-dihydroxyoct-1-enyl)-3-hydroxycyclopentyl)propyl)thiophene-2-carboxylate (11)
[0111] A 20 mL vial equipped with a magnetic stirbar was charged with 210 mg of THP-ether 10 (0.40 mmol) was dissolved in 6 mL of methanol. To this was then added 300 mg of pyridinium p-toluenesulfonate (1.20 mmol) and the mixture was stirred at 17° C. over 17 h. The reaction was sampled by TLC and worked up by concentration in vacuo to remove methanol. The residual products were taken up in ethyl acetate and filtered through a 10 g plug of silica gel, eluting the polar product away from the salts with ethyl acetate (300 mL). Concentration of the filtrate yielded 170 mg of products. Final preparative thin layer chromatographic purification yielded 161 mg (91%) of triol 11 as an oil; 1 H NMR (CDCl 3 ): 1.18 (d, J=6.3 Hz, 3H), 1.36-1.62 (m, 8H), 1.77 (m, 3H), 1.94 (m, 2H), 2.10-2.34 (m, 5H), 2.43 (Br s, 1H), 2.83 (m, 2H), 3.50 (br s, 1H), 3.71 (br s, 1H), 3.79 (m, 1H), 3.86 (s, 3H), 3.98 (m, 1H), 4.09 (m, 1H), 5.51 (m, 2H), 6.78 (dd, J=3.9 Hz, 1H), 7.62 (d, J=3.9 Hz, 1H).
5-(3-((1R,2R,3R,5R)-5-chloro-2-((3S,7R,E)-3,7-dihydroxyoct-1-enyl)-3-hydroxycyclopentyl)propyl)thiophene-2-carboxylic Acid (12)
[0112] A solution of 76 mg of ester 11 (0.17 mmol) in 1 mL of THF was hydrolyzed with 360 uL of aqueous lithium hydroxide (0.5M, 0.18 mmol)) and 0.2 mL of methanol at 24° C. for 6 h. The mixture was acidified by addition of solid sodium hydrogen sulfate (25 mg, 0.18 mmol) and the residual water was removed in vacuo. The residual solid was extracted with ethyl acetate and the product acid was purified by PLC on a 0.5 mm thick preparative silica gel plate eluted in 10% methanol:90% ethyl acetate. Extraction of the UV-active band yielded 43 mg of free acid 12 as an oil (54% yield); 1 H NMR (CD 3 OD): 1.13 (d, J=6.3 Hz, 3H), 1.28-1.63 (m, 8H), 1.75-2.21 (m, 6H), 2.86 (t, J=7 Hz, 2H), 3.70 (m, 1H), 4.04 (m, 3H), 5.52 (m, 2H), 6.86 (br s, 1H), 7.58 (br s, 1H). HPLC purity was 100A %. LCMS (ESI: M + -H 2 0): 413.2.
[0000]
Dimethyl (S)-6-(tert-butyldimethylsilyloxy)-2-oxoheptylphosphonate (13).
[0113] Dimethyl (S)-6-(tert-butyldimethylsilyloxy)-2-oxoheptylphosphonate 13 was prepared according to the procedures described for compound 5 in Scheme 1.
Methyl 5-(3-((1R,2R,3R,5R)-2-((S,E)-7-(tert-butyldimethylsilyloxy)-3-oxooct-1-enyl)-5-chloro-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)propyl)thiophene-2-carboxylate (14)
[0114] To a suspension of 160.3 mg of sodium hydride (60% oil dispersion, 4.00 mmol) in 8 ml of THF at 0° C. was added a solution of dimethyl (S)-6-(tert-butyldimethylsilyl-oxy)-2-oxoheptylphosphonate 13 (1.41 g, 4.00 mmol) in 4 mL THF. The mixture was stirred at 0° C. for 30 min before a solution of aldehyde 7 (1.10 g, 2.65 mmol) in 4 ml of THF was added dropwise. The syringe containing the aldehyde was rinsed with 2 mL of THF to complete the addition and the mixture was stirred at 25° C. for 2.5 h. The reaction was worked up with addition of saturated aqueous ammonium chloride (50 mL) and the aqueous layer was extracted with ethyl acetate (2×75 mL). The ethyl acetate layers were combined and washed with brine, dried over 30 g of anhydrous sodium sulfate, filtered and concentrated in vacuo. FCC (flash column chromatography) purification (silica gel, 6:1 hex/EtOAc) provided 1.60 g (95%) of enone 14.
Methyl 5-(3-((1R,2R,3R,5R)-2-((3S,7S,E)-7-(tert-butyldimethylsilyloxy)-3-hydroxyoct-1-enyl)-5-chloro-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)-propyl)thiophene-2-carboxylate (15)
[0115] Lithium aluminum hydride (7.5 mL of a 1.0M solution in THF, 7.5 mmol) was added to an oven-dried 200 mL flask. A freshly prepared solution of absolute ethanol (11.9 mL of a 1.0M solution in THF, 7.50 mmol) was added dropwise at 23° C. After 15 min a solution of (S)-(−)-1,1′-binaphthol (2.18 g, 7.62 mmol) in THF (10 mL) was added dropwise. The milky-white solution was cooled to −85° C. and a solution of the enone 14 (1.60 g, 2.50 mmol) in THF (9 mL) was added over a 5-10 min period. The reaction solution was stirred for 1 h and then warmed to −78° C. and allowed to stir an additional 3 h. The reaction was then quenched by careful addition of MeOH (3.1 mL). The reaction was then allowed to warm to room temperature and was extracted with EtOAc (2×). The combined organic portions were washed with 1N HCl, saturated aqueous NaHCO 3 , and brine. The organic portion was then dried over anhydrous MgSO 4 ), filtered and concentrated in vacuo. FCC (silica gel, 6:1 hex/EtOAc) afforded 1.20 g (75%) of (S)-alcohol 15.
Methyl 5-(3-((1R,2R,3R,5R)-5-chloro-2-((3S,7S,E)-3,7-dihydroxyoct-1-enyl)-3-hydroxycyclopentyl)propyl)thiophene-2-carboxylate (16)
[0116] Pyridinium p-toluenesulfonate (20.4 mg, 0.081 mmol) was added to a solution of the THP-ether 15 (52 mg, 0.081 mmol) in MeOH (3 mL) at 23° C. The reaction was stirred for 24 h and then concentrated in vacuo. The residue was diluted with EtOAc and washed with 1N HCl, saturated aqueous NaHCO 3 and brine. The organic portion was dried over anhydrous MgSO 4 , filtered and concentrated in vacuo. The crude product was purified by FCC (silica gel, 19:1 EtOAc/MeOH) to afford 34.9 mg (97%) of triol 11.
5-(3-((1R,2R,3R,5R)-5-chloro-2-((3S,7S,E)-3,7-dihydroxyoct-1-enyl)-3-hydroxycyclopentyl)propyl)thiophene-2-carboxylic Acid (17)
[0117] A solution of 40 mg of ester 16 (0.09 mmol) in 0.72 mL of THF was hydrolyzed with 360 uL of aqueous lithium hydroxide (0.5M, 0.18 mmol)) at 23° C. for 16 h. The mixture was acidified by addition of 1N HCl and then extracted with EtOAc (2×). The combined organic portions were washed with brine (2×), dried over anhydrous Na 2 SO 4 , filtered and concentrated in vacuo to yield 23.3 mg (60%) of the free acid 17.
[0118] Different groups for A, X, and Z may be obtained as described elsewhere. See for example, U.S. patent application Ser. No. 11/569,369, filed on Nov. 20, 2006; U.S. Provisional Patent Application Ser. No. 60/886,013, filed on Jan. 22, 2007; and U.S. patent application Ser. No. 11/748,168, filed on May 14, 2007. Other synthetic routes may also be used to reach the compounds disclosed herein.
In Vitro Testing
[0119] U.S. patent application Ser. No. 11/553,143, filed on Oct. 26, 2006, incorporated by reference herein, describes the methods used to obtain the in vitro data in Table 1 below.
[0000]
TABLE 1
EP 2
EP 4
cAMP
Ca 2+ signal
Binding
Ca 2+ signal
Binding
EP 1
EP 3
DP 2
TP
EC 50
%
EC 50
%
EC 50
%
EC 50
%
EC 50
EC 50
EC 50
EC 50
EC 50
AGN-#
(nM)
PGE 2
(nM)
Inh
(nM)
PGE 2
(nM)
Inh
(nM)
(nM)
(nM)
(nM)
(nM)
0.7
100
28
92
530
100
192
75
1507
308
11
3010
0.9
100
34
87
487
102
193
75
1670
2756
21
5270
0.06
106
7.4
99
66
121
145
64
2347
724
499
6792
0.03
107
4
99
25
107
46
81
885
13
6
1816
178
1.47
100
109
78
1219
99
727
29
25
63
4022
68
3306
9
>10 4
3
77
281
90
171
6
>10 4
1.4
91
20
91
381
120
35
98
1279
|
Disclosed herein are compounds having a formula:
Therapeutic methods, medicaments, and compositions related thereto are also disclosed.
| 2
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. application Ser. No. 11/319,093 filed on Dec. 27, 2005 which is a continuation-in-part of U.S. application Ser. No. 10/901,717 filed on Jul. 29, 2004. The disclosure of the above application is incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a method of and an apparatus for producing methanol.
[0003] Methods and apparatuses for conversion of methane into methanol are known. It is known to carry out a vapor-phase conversion of methane into a synthesis gas (mixture of CO and H 2 ) with its subsequent catalytic conversion into methanol as disclosed, for example, in Karavaev M. M., Leonov B. E., et al “Technology of Synthetic Methanol”’, Moscow, “Chemistry” 1984, pages 72-125. However, in order to realize this process it is necessary to provide a complicated equipment, to satisfy high requirements to purity of gas, to spend high quantities of energy for obtaining the synthesis gas and for its purification, and to have a significant number of intermittent stages from the process. Also, for medium and small enterprises with the capacity less than 2,000 tons/day it is not efficient.
[0004] Russian Patent No. 2,162,460 includes a source of hydrocarbon-containing gas, a compressor and a heater for compression and heating of gas, a source of oxygen-containing gas with a compressor. It further includes successively arranged reactors with alternating mixing and reaction zones and means to supply the hydrocarbon-containing gas into a first mixing zone of the reactor and the oxygen-containing zone into each mixing zone, a recuperative heat exchanger for cooling of the reaction, mixture through a wall by a stream of cold hydrocarbon-containing gas of the heated hydrocarbon-containing gas into a heater, a cooler-condenser, a partial condenser for separation of waste gasses and liquid products with a subsequent separation of methanol, a pipeline for supply of the waste gas into the initial hydrocarbon-containing gas, and a pipeline for supply of waste oxygen-containing products into the first mixing zone of the reactor.
[0005] In this apparatus, however, it is not possible to provide a fast withdrawal of heat of the highly exothermic reaction of oxidation of the hydrocarbon-containing gas because of the inherent limitations of the heat exchanger. This leads to the necessity to reduce the quantity of supplied hydrocarbon-containing gas and, further, it reduces the degree of conversion of the hydrocarbon-containing gas. Moreover, even with the use of oxygen as an oxidizer, it is not possible to provide an efficient recirculation of the hydrocarbon-containing gas due to fast increase of concentration of carbon oxides in it. A significant part of the supplied oxygen is wasted for oxidation of CO into CO 2 , which additionally reduces the degree of conversion of the initial hydrocarbon-containing gas and provides a further overheating of the reaction mixture. The apparatus also requires burning of an additional quantity of the initial hydrocarbon-containing gas in order to provide a stage of rectification of liquid products with vapor. Since it is necessary to cool the gas-liquid mixture after each reactor for separation of liquid products and subsequent heating before a next reactor, the apparatus is substantially complicated, the number of units is increased, and additional energy is wasted.
[0006] A further method and apparatus for producing methanol is disclosed in the patent document RU 2,200,731, in which compressed heated hydrocarbon-containing gas and compressed oxygen-containing gas are introduced into mixing zones of successively arranged reactors, and the reaction is performed with a controlled heat pick-up by cooling of the reaction mixture with water condensate so that steam is obtained, and a degree of cooling of the reaction mixture is regulated by parameters of escaping steam, which is used in liquid product rectification stage.
[0007] Other patent documents such as U.S. Pat. Nos. 2,196,188; 2,722,553; 4,152,407; 4,243,613; 4,530,826; 5,177,279; 5.959,168 and International Publication WO 96/06901 disclose further solutions for transformation of hydrocarbons.
[0008] It is believed that the existing methods and apparatus for producing methanol can be further improved.
SUMMARY
[0009] It is accordingly an object of the present invention to provide a method of and an apparatus for producing methanol, which is a further improvement of the existing methods and apparatuses.
[0010] It is another feature of the present teachings to provide a method of and an apparatus for producing methanol which can be used with minimal processing of gas and gas-condensate deposits, and also at any gas consumer, such as power plants, gas distributing and gas reducing stations, chemical production facilities, etc., or small methane producers, (i.e., coal mines, oil production (flares), landfills, farms.)
[0011] In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a method of producing methanol, which includes the steps of supplying into a reactor a hydrocarbon-containing gas stream, supplying into the reactor an oxygen containing gas; carrying out in the reactor an oxidation of the hydrocarbon-containing gas by oxygen of said oxygen-containing gas; and, after removing impurities and products of the reaction, recycling un-reacted hydrocarbon gas into the hydrocarbon-containing gas stream for further reaction.
[0012] Another feature of the present teachings is an apparatus for producing methanol, which has a reactor for receiving and reacting a hydrocarbon-containing gas stream with an oxygen-containing gas, to carry out in the reactor oxidation of the heated hydrocarbon-containing gas by oxygen of said oxygen-containing gas. The apparatus also has a means for supplying into the reactor a cold hydrocarbon-containing gas to be mixed directly with a mixture of said heated hydrocarbon containing gas and said oxygen containing gas at a later stage of the reaction to inhibit the decomposition of formaldehyde. Un-reacted hydrocarbon gas is then processed to remove products and contaminants before being recycled back into the hydrocarbon-containing gas stream.
[0013] As can be seen, in accordance with the present teachings, a heated hydrocarbon-containing gas stream and oxygen-containing gas are supplied into a reaction zone or into a reactor, where a gas phase oxidation of the hydrocarbon-containing gas is performed at elevated temperature and pressure in the reaction zone. The reaction mixture is cooled before and is separated into waste gas and liquid product. The waste gas is scrubbed to remove CO 2 and returned to the heated hydrocarbon-containing gas stream. Cold hydrocarbon-containing gas is supplied into a regulation zone of the reactor to reduce the reaction temperature for example by 30-90° C. and thereby to provide a production and a redistribution of the ratio of products to produce corresponding quantities of methanol and formaldehyde.
[0014] In accordance with the present teachings, during cooling of the reaction mixture in the partial condenser, heat is transmitted to an input stream supplied into a formaldehyde rectification column for performing rectification of formaldehyde and simultaneous regeneration of the primary scrubber solvent, methanol. Within the partial condenser, dry gas is separated from raw liquids, including methanol, ethanol, and water. The raw liquids, through the flash drum, are supplied into a rectification column. The temperature of the top of the column is, between about 70 and about 75° C., the pressure in the column is, for example, up to 0.2 MPa. The final product is supplied to storage or further processing. The dry gas is scrubbed to remove CO 2 and formaldehyde and is then returned to the reactor in the hydrocarbon input stream.
[0015] The time of presence of the reaction mixture in the reactor is about 1.2 sec. The period of induction takes approximately 70% of this time, and thereafter a significant temperature increase of the mixture takes place. The content of methanol in the reacted gas is about 40% due to its high stability and selectivity, while the content of the formaldehyde is about 4% due to its lower stability and selectivity. In order to increase the portion of formaldehyde to 8-13% in the final product, the temperature of the reaction is reduced by 30-90° C. after the period of induction (after the formaldehyde has been formed) at 0.7-1.4 sec of reaction due to the injection of the cold hydrocarbon-containing gas into the regulating zone.
[0016] When the temperature of reaction is changed from 370° C. to 450° C., the content of aldehydes is increased from 5% to 13% and the content of organic acids is increased from 0.5% to 0.7%. The selectivity which is close to a maximum with respect to liquid organic products, including methanol and formaldehyde, is maintained using a concentration of oxygen in the initial gas mixture 2-2.8%.
[0017] The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1A and 1B are views schematically showing a system of an apparatus for producing methanol in accordance with the present teachings;
[0019] FIGS. 2 and 3 are views illustrating concentrations of oxygen, formaldehyde and methanol during reactions in accordance with the prior art and in accordance with the present invention correspondingly; and
[0020] FIG. 4 represents a graph depicting the yield oxygenates of the system as a function of recycle ratio
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] An apparatus for producing methanol in accordance with the present invention has a reactor 100 which facilitates a gas phase oxidation of a hydrocarbon-containing gas are shown in FIGS. 1A and 1B . FIG. 1B details the inputs and outputs of the reactor. The reactor 100 has a reaction zone 102 which is provided with a device 104 for introducing a heated hydrocarbon-containing gas stream and a device 105 for introducing an oxygen-containing gas. As explained in detail below, the oxygen-containing gas preferably has greater than 80% oxygen content to reduce the accumulation of inert gases due to the recycling process.
[0022] The reactor 100 further has a regulation zone 108 provided with an optional device 110 for introducing a cold hydrocarbon-containing gas stream for reducing the temperature of reaction during operation of the apparatus. In addition, the reactor 100 is provided with thermal pockets 112 for control and regulation of temperatures in corresponding zones, provided for example with thermocouples.
[0023] The apparatus has a device 114 for cooling the reaction mixture before separation. Additionally, the partial condenser 122 incorporates a gas-liquid heat exchanger to further reduce the temperature of the products. The condenser 122 separates H 2 O and alcohols from a hydrocarbon-CO 2 mixture. The partial condenser 122 is preferably isobaric, as opposed to isothermal, to avoid pressure losses. The product stream enters, and liquid stream and gaseous stream exit the condenser 122 .
[0024] Block 139 represents equipment which is configured to separate contaminants and products from a hydrocarbon-containing recycle gas component. In this regard, the equipment 139 is configured to remove CO 2 from the reduced product stream. The equipment 139 can take the form of a purge valve, absorber, membrane separator, or an adsorber. It is envisioned the equipment 139 can be used to regulate the percentage of other non-reactive components such as N 2 with, for example, a purge valve.
[0025] In the event the system is configured to recover formaldehyde, the gaseous reduced product stream leaves the isobaric condenser 122 and is passed to the scrubber 134 . The scrubber 134 prevents the accumulation of CO 2 and allows the physical capture of formaldehyde. The scrubber 134 can utilize a mixture of methanol and water to physically absorb formaldehyde and CO 2 from the hydrocarbon gas recycle loop 135 . The efficiency of the scrubber 134 , which can operate adequately without refrigeration, is made possible due to the high operating pressure of the recycle loop 135 . This is opposed to cryogenically low temperatures utilized by traditional absorption processes. Other potential methods which can be utilized use materials such as various amines known to remove CO 2 and formaldehyde.
[0026] The gases enter the scrubber 134 as a “dirty” gas with some amount of formaldehyde and CO 2 present. These components will only be present in relatively dilute amounts, so the duty of the methanol absorbent is also relatively small. To fulfill the minimum absorption requirements, modification of the flow rate of methanol or operating temperature of the scrubber column can be used. If it is desirable to operate at extremely low absorbent flow rates, then a lower temperature can be utilized, for example 0° C. If it is desirable to operate at ambient temperatures or temperatures achievable via cooling water, then a high flow rate can be utilized, for example, ten times that of the flow rate for 0° C. In either scenario, the pregnant methanol absorbent stream 14 is completely regenerated by the formaldehyde distillation column 138 . Optionally, the stream 14 from the scrubber 134 can be passed through the condenser 122 to provide cooling of the product stream and preheating of the methanol recycle to improve the energy efficiency of the formaldehyde distillation column 138 .
[0027] The reactor 100 is connected with a compressor 124 and heater 126 for supply of compressed and heated oxygen-containing gas. The raw hydrocarbon-containing gas is mixed with cleaned hydrocarbon gas from the scrubber 134 and is heated using a heater 136 . In the event the raw hydrocarbons have a high CO 2 content, the raw hydrocarbons can be mixed with the reduced product hydrocarbon stream from the condenser 122 prior to the entry of the scrubber 134 for removal of contaminant gases prior to entering the reactor.
[0028] The apparatus further has a unit for rectification of methanol which includes a flash drum 132 , rectification column 128 , and a vessel 130 from which methanol is supplied to storage or further processing. This rectification column 128 is used to separate methanol (light-key component) from ethanol (heavy-key component) and water (non-key component). As before, it is desirable for a portion of the heavy key to enter the distillate stream (as dictated by commercial specification for formalin). For methanol rectification, 99% or higher purity is typical and 99.999% is achievable with multiple columns. Stream 4 enters the column and the distillate, stream 5 , and bottoms, stream 8 , exit the column in liquid phase. Stream 8 has some amount of ethanol (and perhaps methanol, if ultra pure methanol was produced) and will be used as the basis of the aqueous makeup of the commercial formalin stream (stream 11 ). In this manner, some of the ethanol is recovered before the remainder is discarded in the liquid waste stream.
[0029] Disposed between the column 128 and the condenser 122 is a flash drum 132 for removal of CO 2 and formaldehyde from the liquid product stream. The purpose of the flash drum 132 is to drop the pressure to an appropriate level before entry into the methanol rectification column 128 and to substantially remove any dissolved gases, typically CO 2 and formaldehyde, from the liquid product stream.
[0030] In operation, the raw hydrocarbon-containing gas stream with a methane content for example up to 98% and the reduced hydrocarbon product stream are supplied from an installation for preparation of gas or any other source to the heater 136 , in which it is heated to temperature 430-470° C. The heated hydrocarbon-containing gas is then supplied into the reaction zone 102 of the reactor 100 . Compressed air with pressure, for example, of 7-8 MPa and with a ratio 80% to 100% and, preferably, 90% to 95% oxygen is supplied by the compressor 124 also into the reaction zone 102 of the reactor 100 . Oxidation reaction takes place in the reaction zone 102 of the reactor 100 . Between 2.0 and 3.0% O 2 of the total volume of the reactants are reacted with the heated hydrocarbon-containing gas stream as previously described. To limit the amount of N 2 within the system, for example to less than 30%-40%, or reduce the requisite size of the purge stream to achieve the same, the O 2 stream is preferably substantially pure, thus limiting the amount of N 2 entering the system. An optional second stream of cold or in other words a lower temperature hydrocarbon-containing gas than the gases in the reactor is supplied through the introducing device 108 into the regulation zone of the reactor 100 . This stream is regulated by the regulating device 120 , which can be formed as a known gas supply regulating device, regulating valve or the like. This cold stream can be composed of a raw hydrocarbon stream, a recycled stream, or a portion or combination of the two. The regulator is configured to adjust the volume or pressure of cold hydrocarbon-containing gas based on system parameters such as, but not limited to, pressure, temperature or reaction product percentages down stream in the system.
[0031] Depending on the intended mode of operation of the apparatus, in particular the intended production of methanol or methanol and formaldehyde, the reaction mixture is subjected to the reaction in the reactor without the introduction of the cold hydrocarbon-containing gas if it is desired to produce exclusively methanol. The introduction of the cold hydrocarbon containing gas is used when it is desired to produce methanol and formaldehyde. By introduction of the cold hydrocarbon-containing gas, the temperature of the reaction is reduced for example by 30-90° so as to preserve the content of formaldehyde into the separated mixture by reducing the decomposition of the formaldehyde to CO 2 .
[0032] The reaction mixture is supplied into the heat exchanger 114 for transfer of heat to the reactor input stream from the reaction mixture exiting the reactor, and after further cooling is supplied within partial condenser 122 . Separation of the mixture into high and low volatility components, (dry gas and raw liquid, respectively) is performed in the partial condenser 122 which may absorb at least some of the formaldehyde into the raw liquid stream as desired. The dry gas is forwarded to a scrubber 134 , while the raw liquids from the condenser 122 are supplied to the flash drum 132 .
[0033] The scrubber 134 functions to remove the CO 2 and formaldehyde from the dry gas stream. In this regard, the scrubber 134 uses both H 2 O and methanol at between 7-8 MPa pressure and between about 0° C. and about 50° C. to absorb CO 2 and formaldehyde. Once the CO 2 and formaldehyde are removed, the reduced stream of hydrocarbon gas is recycled by mixing the reduced stream with the raw hydrocarbon-containing gas stream either before or within the reactor, as desired. The raw hydrocarbon and reduced streams, individually or in combination, are then inputted into the reaction chamber 100 at input 104 or input 110 after being heated by heat exchanger 116 and heater 136 as previously described.
[0034] The rectification column is used to separate carbon dioxide (non-key component) and formaldehyde (light-key component) from methanol (heavy-key component) and water (non-key components). The pregnant methanol steam, stream 14 , enters the rectification column and is separated into a formaldehyde distillate, stream 16 , and a bottoms stream, stream 15 . Some amount of methanol in the distillate stream is desirable since methanol is used as a stabilizer for the production of commercial grade formalin (6-15% alcohol stabilizer, 37% formaldehyde, and the balance being water). By allowing a portion of the heavy key into the distillate stream the separation is more easily achieved; furthermore, process losses typically experienced during absorbent regeneration are subsequently nullified as methanol within the distillate is used for formalin production. Stream 15 is supplemented by stream 31 so as to replace any methanol which was transferred to the distillate stream, stream 16 . Combining stream 31 and stream 15 results in stream 17 , which then returns to the scrubber 134 as regenerated methanol absorbent. Meanwhile, the formaldehyde distillate, stream 16 , combines with the vapors from flash drum 132 , stream 7 , to form a mixture of formaldehyde, methanol, and carbon dioxide.
[0035] The formaldehyde, water, methanol and CO 2 removed by scrubber 134 are passed to formaldehyde rectification column 138 . Column 138 removes formaldehyde and CO 2 from the methanol-water stream. Small amounts of methanol are combined with produced methanol and are inputted into the scrubber 134 to remove additional amounts of CO 2 and formaldehyde from the reduced hydrocarbon stream.
[0036] Free or non-aqueous formaldehyde is allowed to remain in the gas phase by operation of the isobaric condenser 122 . The liquid methanol product stream, or raw liquids, would then comprise methanol, ethanol, and water by allowing formaldehyde to remain in the gaseous stream. In this case, the liquid stream exiting the isobaric condenser 122 can bypass the formaldehyde rectification portion of the process and enter the methanol rectification column after having optionally passed through the flash drum 132 .
[0037] FIGS. 2 and 3 show diagrams of the concentration of oxygen, formaldehyde and methanol in reactions without cooling and with cooling, respectively.
[0038] As can be seen from FIG. 2 , approximately after 2 sec, oxygen is burnt completely. At this moment the reaction temperature reaches its maximum and methanol and formaldehyde are produced with their proportions in the reaction mixture. Methanol is a more stable product at the end of the reaction and its concentration remains substantially stable after reaching its maximum concentration. Formaldehyde is less stable, and therefore with a temperature increase (the temperature increases until oxygen is burnt completely) its concentration somewhat reduces.
[0039] In the reaction with the cooling shown in FIG. 3 , via the introduction of cold gas when the formation of methanol and formaldehyde is completed, the temperature of a final period of the reaction is reduced so as to inhibit the decomposition of formaldehyde.
[0040] FIG. 4 represents a graph depicting the yield of oxygenates for the system as a function of the recycle ratio of the recycling hydrocarbon gasses. Shown is a graph depicting the use of Michigan Antrim gas having 97% CH 4 and 1% N 2 . In this regard, the graph shows a significant increase in product yield using the same input stream and with little increase in capital costs. As the system efficiently manages pressure and integrates process energy usage, energy requirements are minimized, thus increasing the overall system economics.
[0041] 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 methods and constructions differing from the types described above.
[0042] While the invention has been illustrated and described as embodied in the method of and apparatus for producing methanol, 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.
[0043] 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. What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.
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An apparatus and method of producing methanol includes reacting a heated hydrocarbon-containing gas and an oxygen-containing gas in a reactor; to provide a product stream comprising methanol; and transferring heat from the product stream to the hydrocarbon-containing gas to heat the hydrocarbon containing gas. After removing methanol and CO 2 from the product stream, unprocessed hydrocarbons are mixed with the hydrocarbon containing gas fro reprocessing through the reactor.
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BACKGROUND OF THE INVENTION
The invention relates to a light, especially, a taillight, for motor vehicles comprising at least one light means arranged behind a light screen at the peripheral edge of the housing.
Known taillights are equipped with a light means that is positioned on the housing wall behind the light screen. The light means is usually an incandescent light bulb illuminating the light screen. Frequently, the light screen is not fully illuminated by this light means.
It is an object of the present invention to design a taillight such that the light screen is illuminated across its entire surface perfectly and in a simple manner.
SUMMARY OF THE INVENTION
This object is solved with the inventive design such that a light source is arranged at the edge of the light. The light screen can thus be reliably illuminated across its entire surface. The light screen can also be illuminated in different colors and thereby perform different functions. If the light, respectively, its light screen is illuminated in red, the light can serve as a rear light or a brake light. The light source can be arranged at the edge of the taillight in a constructively simple manner and at low costs.
BRIEF DESCRIPTION OF THE DRAWINGS
The object and advantages of the present invention will appear more clearly from the following specification in conjunction with the accompanying drawings, in which:
FIG. 1 shows a plan view of an inventive light in a schematic view;
FIG. 2 shows an enlarged cross-sectional view along line II—II of FIG. 1 .
DESCRIPTION OF PREFERRED EMBODIMENTS
The taillight illustrated in the drawings has a housing 1 with a housing wall 1 a . A light screen 2 is arranged in front of the housing wall 1 a at a distance to it and is connected to the housing wall 1 a via a peripheral edge 4 that is part of the housing 1 . The peripheral edge 4 and the housing wall 1 a can be embodied as a monolithic part forming the housing 1 . In the rear of the light screen 2 , an optic 3 is provided, for example, a Fresnel optic. The peripheral edge 4 has a Z-shaped cross-section with a longer leg 5 which connects to the housing wall 1 a . The rim of the light screen 2 rests against the shorter leg 6 of the peripheral edge 4 . In the illustrated embodiment, the light screen 2 is curved in a circular arc shape. Of course, the housing wall 1 a and the light screen 2 can have any other suitable shape. The interior surface of the housing wall 1 a is embodied as a reflective surface 7 . It is also possible to attach a reflecting member to the interior surface of the housing wall 1 a . In the illustrated embodiment the housing wall 1 a has three openings 8 . Each opening 8 is provided with a printed circuit board 9 whose interior board surface carries a number of LEDs 11 arranged adjacent to one another. In the area of the openings 8 , the light screen 2 is provided with one light window 14 to 16 for each opening 8 . The light emitted by the respective LEDs 11 of the board 9 passes through the light windows 14 to 16 toward the outside. The light windows 14 to 16 , and also preferably the corresponding openings 8 of the housing wall 1 a , can have various sizes and/or shapes.
For example, the light window 14 can function as a turn signal and is colored yellow for that purpose. The light window 15 can be colored red and function as a brake light. Finally, the light window 16 can, for example, function as the rear light and can be colored red, accordingly. The light windows 14 to 16 can be provided at their inwardly facing sides with corresponding optics. It is also possible to use differently colored LEDs 11 for the different light windows 14 to 16 so that the light windows can consist of a transparent material. It is also possible to color the light windows 14 to 16 accordingly and to arrange correspondingly colored LEDs 11 at their inwardly facing sides. Instead of light means in the form of LEDs 11 , it is also possible to employ fluorescent lights, neon lights, incandescent light bulbs or the like. Furthermore, it is possible to separate the individual light windows 14 - 16 from one another, at least, partially, e.g., by walls extending between the housing wall 1 a and the light screen 2 . This warrants that no stray light can impinge on the respective light windows 14 to 16 . The light screen 2 can also be designed without the above described light windows. In that case, the respective areas of the light screen 2 light up when the respective LEDs 11 are activated.
At the peripheral edge 4 , a further light source/sources are provided, preferably LEDs. Advantageously, a number of such LEDs is arranged in series about the peripheral edge 4 . They can be provided either about a part of the peripheral edge 4 only, as illustrated in FIG. 1, or they can also be provided about the entire circumference of the peripheral edge 4 . The LEDs (light sources) 12 are distributed such as to indirectly illuminate the entire light screen 2 . Furthermore, a very flat structural design of the taillight is possible by using LEDs.
The LEDs 12 are arranged on a printed circuit board 17 which is supported at the peripheral edge 4 in a suitable way. Because of the Z-shaped cross-sectional embodiment of the edge 4 , the printed circuit board 17 and the LEDs 12 are positioned in a receiving portion 18 which is laterally delimited by the housing wall 1 a and the lateral stay 19 of the peripheral edge 4 . The LEDs protrude partially from the receiving portion 18 into the interior of the taillight. The light beams emitted from the LEDs impinge preferably exclusively upon the reflective interior surface 7 from where they are reflected to the light screen 2 . In this manner, the entire light screen 2 is indirectly illuminated. It is also possible, to arrange the LEDs 12 such that the light beams emitted by them partially impinge directly upon the light screen 2 and partially upon the reflective interior surface 7 at which they are reflected to the light screen 2 . In this manner, the light screen 2 is also optimally illuminated across its entire surface. The reflective interior surface 7 needs to be provided only in that area of the housing wall 1 a in which the light beams emitted by the LEDs 12 impinge upon the housing wall 1 a . The light screen 2 can have a desired color, e.g., corresponding to the vehicle color. It is also possible to color the LEDs 12 accordingly. Instead of the LEDs 12 , neon lights, fluorescent lights, incandescent light bulbs and the like can be used also.
In the illustrated embodiment, the taillight is a complete taillight assembly which comprises, e.g., the brake light, the turn signal, and the rear light. However, it is also possible to embody each individual light such that the light screen is illuminated by the LEDs 12 directly and indirectly in the described manner. In this case, the light screens are colored corresponding to the signal colors yellow (turn signal), red (brake and rear light) or clear (backing-up light), or the LEDs are provided with a corresponding color. The LEDs 11 and 12 as well as the corresponding printed circuit boards 9 and 17 , respectively, are connected to the vehicle's electrical system.
The specification incorporates by reference the disclosure of German priority document 198 15 963.3 of Apr. 9, 1998.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
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A light for motor vehicles has a housing having a peripheral edge. A light screen is connected to the peripheral edge of the housing. At least one light source is arranged at least at a portion of the peripheral edge behind the light screen within the housing.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus controlled by a microprocessor, and more particularly to an apparatus controlled in a predetermined safe state even when the microprocessor is in a faulty state.
2. Description of the Prior Art
As an example of an apparatus controlled by a control circuit using a microprocessor, there is a forced flow air heating apparatus, called an FF type heating apparatus. In such an apparatus, if the microprocessor goes wrong, the apparatus is controlled in an abnormal condition and thus might be in an extremely dangerous state. Therefore, it is demanded to detect a fault of the microprocessor in such a case and to control the apparatus so as to protect it from the danger. Nevertheless, a conventional apparatus of this type is not controlled under a safety state since it does not respond to a fault of the Summary of the Invention.
Accordingly, an object of the invention is to provide an apparatus controlled by a microprocessor which is to controlled in a safe state when the microprocessor is out of order.
According to an embodyment of the invention, there is provided an apparatus controlled by a microprocessor which has an integrated microprocessor, a detecting circuit and a protecting circuit. The integrated microprocessor includes a time counting logic circuit supplied with a reference input signals for counting the input signals and producing a first signal, a main control logic for receiving the first signal for producing a second signal and at least one output signal for controlling the apparatus, and an AC signal generating logic for receiving the first and second signals in order to produce an AC signal and a third signal whereby the AC signal is produced at a first operation state of the microprocessor and the AC generating logic has first and second levels repeated alternately with the third signal produced by a second operation state of a microprocessor and wherein the third signal has one of either the first or second levels for a predetermined period of time. The detecting circuit detects the AC signal and produces a first detection signal and detects the third signal and produces a second detection signal. The protecting circuit is connected to the detecting circuit and applies a fourth signal to the apparatus for putting the apparatus in a safety condition when the protecting means receives the second detection signal.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily attained as the same becomes better understood by reference to the following detained description when considered in connection with the accompanying drawings, wherein:
FIG. 1 shows a schematic diagram of a forced flow air heating apparatus controlled by a control circuit using a microprocessor;
FIG. 2 shows a block diagram of a control circuit for controlling the apparatus shown in FIG. 1;
FIG. 3 shows a flow chart of a control program of a time counting circuit shown in FIG. 2;
FIGS. 4A and 4B cooperate to form a flow chart of control programs of the control circuit shown in FIG. 1;
FIGS. 5A through 5F show wave forms at the respective portions of the control circuit shown in FIG. 2 when the AC signal generator shown in FIG. 2 produces a first abnormal output signal; and
FIGS. 6A through 6F show wave forms at the respective portions of the control circuit shown in FIG. 2 when the AC signal generator shown in FIG. 2 produces a second abnormal output signal.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof, reference numeral 1 designates an AC power source; 2 a motor for combustion for feeding air to a combustion section; 3 a fan motor for circulating air within a room through a heating section which is switchable between a high speed and a low speed; 4 a drive coil for an oil feeding valve 4a for high combustion; 5 a drive coil for an oil feeding valve 5a for low combustion; 6 an ignition transformer for igniting a burner (not shown). The AC power souce 1 is connected at one end with a line l 1 through a first switch 7 and at the other end with a line l 2 . The first switch 7 is turned off when a first relay 15 is not activated (input="1"), and turned on when it is activated. The combustion motor 2 is connected between the lines l 1 and l 2 . The fan motor 3 is connected at one end to the line l 2 and at the other end to the line l 1 through a second and third switches 8 and 9. When a second relay 16 is not activiated (input="1"), the lever of the second switch 8 is switched on a contact 8a connected to a lead for high speed of the fan motor 3. When the relay 16 is activated (input="0"), the lever is switched on a contact 8b connected to a lead for low speed. The third switch 9 is closed when a 3rd relay 17 is activiated (input="0"). The coils 4 and 5 are connected at one ends to the line l 2 and at the other ends to the line l 1 through a fourth switch 10. The lever of the switch 10 contacts to a contact 10a when a 4th relay 18 is not activiated (input="1"), and contacts to a contact 10b when it is activiated (input="0"). The ignition transformer 6 is connected at one end to the line l 2 and the other end to the line l 1 through the switch 11. The ignition transformer 6 is closed only when a fifth relay 19 is activiated (input="0").
FIG. 2 shows an example of a control circuit for controlling the apparatus shown in FIG. 1. The control circuit includes a microprocessor 12, a pulse generator 13, a detecting circuit 14a for detecting an abnormality of an AC signal produced from the microprocessor 12, a circuit 14b which responds to an abnormality of the AC signal to control the apparatus shown in FIG. 1 in a given safe state, the relays 15 and 19, and drivers 28 to 31 for the relays 16 to 19.
The microprocessor 12 includes a time counting logic circuit 20, a main control logic circuit 21, and an AC signal generating logic circuit 25. The pulse generator 13 wave-shapes an AC input signal of 50 Hz, for example, supplied to the terminal 13a through an integrating circuit 22 including a resistor 13b and a capacitor 13c, and inverters 23 and 24 and applies the output signal 13d of 50 Hz to the input terminal of the time counting circuit 20. The time counting logic circuit 20 includes first, second, . . . counters. The first counter counts the "1" level of the input signal 13d for 0.1 second. That is to say, when counting the "1" level of the input signal 13d five times, the first counter produces a carry. The second counter counts one second by counting the carry of 0.1 second produced by the first counter ten times. The third counter performs a given time count on the basis of one second signal of the second counter. The first counter produces a first signal (also called a 0.1 sec signal or a flag setting signal) at the time that the carry is produced every 0.1 second. The first signal is applied to the main control logic circuit 21 and the AC signal generating logic circuit 25 at the same timing. Further, the every-one second signal of the second counter also is applied to the main control logic circuit. The operation of the time counting logic circuit 20 is controlled in accordance with a program shown in FIG. 3 which is set in the main control logic circuit 21.
The main control logic circuit 21 further stores programs shown in FIGS. 4A and 4B and to be described later. In response to an operation from outside or input information from the time counting logic circuit 20, the main control logic circuit 21 executes a given program to produce output signals of `1` or `0` at the output terminals O 2 to O 6 . The main control logic circuit 20 also produces a second signal 21a which is not synchronous with the first signal 20a received from the time counting logic circuit 20.
The microprocessor 12 includes a flag memory 25a. The flag memory stores a flag when the AC signal generator logic circuit 25 receives the first signal 20a and the flag is cleared when the AC signal generating logic circuit 25 receives the second signal 21a. The first signal 20a is supplied to the flag memory 25a at the time that the first counter of the time counting logic circuit 20 is carried every 0.1 second and the second signal 21a is supplied to the same at a timing not synchronous with the first signal 20a. The AC signal generating logic circuit 25 includes a flip-flop circuit 25b. The FF circuit inverts its output level when the flag is cleared. Accordingly, an AC signal with first and second levels is applied to the output terminal O 1 .
How to control the time counting logic circuit 20 will be described with reference to FIG. 3. To start, a start button is operated (step 3-1). Then, it is checked as to if the input signal 13d to the time counting circuit 20 is `1` or not (step 3-2). If the level of the input signal 13d is not `1`, the program execution steps to a step 3-8 and the time counting circuit does not effect a given operation. When the level of the input signal 13d is `1`, the first counter of the time counting logic circuit counts the input signal 13d for 0.1 second (step 3-3). In a step 3-4, it is checked if a carry is effected in the first counter or not. When no carry is effected, the program execution advances to a step 3-8, and the time counting circuit 20 does not operate. When a carry is effected, the time counting circuit produces a first signal (flag setting signal) and the second counter counts the 0.1 Sec. signal. See step 3-5. Then, a step 3-6 checks as to if the second counter counts the 0.1 Sec. signal or not. When the count of 0.1 Sec. signal is not effected, the program execution is shifted to step 3-8 and the time counting circuit does not effect a given operation. On the other hand, when the count of 0.1 Sec. signal is effected, the second counter counts time every one second (step 3-7). If the every-one-second time count is performed, the time counting logic circuit 20 operates normally.
In the main control logic circuit 21, the programs shown in FIGS. 4A and 4B are further set and the main control logic circuit 21 operates in accordance with the programs. The programs shown in FIGS. 4A and 4B are roughly classified into a stop program P1, an ignition program P2, a combustion program P3, and a post purge program P4. Here, the post purge program is executed to purge remaining combustible gas after the combustion program P3 is executed.
In the stop program P1, following the start step P1-1, a step P1-2 checks if a start switch (not shown) is turned on or not. If it is not turned on, a step P1-3 checks if a flag (0.1 second flag) is set in the flag memory 25a of the microprocessor 12. If the 0.1 second flag is set therein, the 0.1 second flag is immediately cleared, and at the trailing edge of the 0.1 second flag the output level of the FF circuit 25b is inverted (step P1-4). Following the step P1-4, a stop sequence program controls the apparatus (FIG. 1) to stop it. In step P1-3, when the 0.1 second flag is not set, the program execution directly steps to a step P1-5 without passing the step P1-4. When the stop sequence program is executed, at least the first, third and fifth relays 15, 17 and 19 are deenergized (input="1"), the first, third and fifth switches 7, 9 and 11 are released. At the step P1-2, when the start switch is turned on, the ignition program P2 is executed.
In the ignition program P2, a step P2-1 checks if the apparatus is in `ready-for-operation` (the apparatus shown in FIG. 1 is set in a given `ready-for-operation`) or not. When it is in `ready-for-operation`, a step P2-2 checks as to if the execution of an ignition sequence program is completed or not. If the ignition sequence program execution is not yet completed, a step P2-3 checks if the 0.1 second flag is set in the flag memory 25a of the microprocessor 12 or not. When the 0.1 second flag is set therein, the 0.1 second flag is immediately cleared to invert the output level of the FF. See step P2-4. When the execution of the program of the step P2-4 is completed, the ignition operation is performed in accordance with the ignition sequence program (step P2-5). When the 0.1 second flag is not set, the ignition sequence program is immediately executed without executing the step P2-4. Through the execution of the ignition sequence program, at least the first, third and fifth relays 15, 17 and 19 are energized (input="0") to close the first, third and fifth switches 7, 9 and 11. When the step P2-2 checks that the execution of the ignition sequence program is completed, the execution of the combustion program P3 is started.
In the combustion program P3, a step P3-1 checks if the apparatus shown in FIG. 1 is in an operable state or not. If it is in the operable condition, a step P3-2 checks as if the 0.1 second flag is set, it is immediately cleared to invert the output level of the flip-flop circuit 25b in a step P3-3. When the execution of the program in the step P3-3 is completed, the combustion operation is performed in accordance with the combustion sequence program in a step P3-4. In the step P3-2, if it is checked that the 0.1 second flag is not set, the program execution skips a step P3-3 to the execution of the combustion sequence program (step P3-4). Through the execution of the combustion sequence program, the fifth relay 19 is deenergized and the fifth switch 11 is open. Simultaneously, in accordance with the high or low combustion set, the second and fourth relays 16 and 18 are deenergized or energized, so that the third and fourth switches 8 and 10 are selectively switched in accordance of the setting of the low or high combustion. When the apparatus is not in the operable condition in the step P2-1 of the ignition program P2 and the step P3-1 of the combustion program P3, the execution of the post purge program P4 is started.
In the post purge program P4, it is checked if the post purge is completed or not (step P4-1). If it is not completed, a step P4-2 checks if the 0.1 second flag is set in the flag memory 25a or not. If the post purge is not completed, it is checked if the 0.1 second flag is set in the flag memory 25a of the microprocessor or not. See step P4-2. If it is set, the 0.1 second flag is cleared to invert the output level of the flip-flop 25b (step P4-3). When the step P4-3, ends, the post purge is executed in accordance with the post purge sequence program (step P4-4). When the step P4-2 finds that the 0.1 second flag is not set, the program execution skips the step P4-3 to the execution of the post purge sequence program in step P4-4. When the step P4-1 finds the post purge ends, the program execution shifts to the step P1-2 of the stop program P1.
As described above, it is always checked if the 0.1 second flag is set or not in the flag memory of the AC signal generator 25. And if the 0.1 second flag is set, the output level of the flip-flop circuit 25b is inverted without fail by clearing the flag. So far as the microcomputer 12 or the pulse generator 13 does not go wrong, an AC signal is led to the output terminal O 1 of the AC signal generator 25. When it goes wrong, abnormality is detected in the AC signal at the output terminal O 1 .
As seen from the process of the executions of the programs shown in FIGS. 4A and 4B, a signal to control the respective switches shown in FIG. 1 is produced from the main control section 21. The output terminals of the main control sections are denoted as O 2 to O 6 . The same denotations are also applied to the output signals produced from the output terminals. FIG. 2 will further be described. The output O 2 is applied to one of the input terminals of the AND gate 27 through the inverter 26. The outputs O 3 to O 6 are supplied to the input terminals of the drive circuits 28 to 31, respectively. The output of the AND gate 27 is applied through an inverter 32 to the first relay 15 and the outputs of the drivers 28 to 31 are applied to the second to fifth relays 16 to 19. respectively.
The AC signal check circuit 14a is a logic circuit for applying a signal `1` to the output terminal Q 3 . When an abnormality is not found in the AC signal at the output terminal O 1 , and applying a signal `0` to the same when the AC signal is abnormal. The logic circuit 14a is comprised of a first capacitor 33 connected at one end to the output terminal O 1 , a first diode 38 connected at the anode to the other terminal Q 1 of the first capacitor 33 and at the cathode to a positive terminal of a DC source +V DD , a first resistor 34 connected in parallel to the first diode, a first inverter 35 connected between the other end of the first capacitor 33 and one end of a second resistor 36, a second capacitor 37 connected between the other end Q 2 of the second resistor 36 and a positive terminal of the DC source +V DD , a second diode 39 connected between at the anode to one end of the second resistor 36 and at the cathode to the other end of the second resistor, and second and fourth inverters 40 and 41 connected in series between the other end of the second resistor 36 and the output terminal Q 3 of the circuit 14a.
During a period that the pulse generator 13 produces a normal output signal 13d and the microcomputer 12 normally operates, the wave forms at the respective points of the circuit 14a are as shown in FIGS. 5A to 5F. In the period T 1 , the capacitor 33 is charged through the resistor 34 by the power source V DD so long as the AC signal (FIG. 5A) is `0`, so that a wave form at point Q 1 is as shown in FIG. 5B. Since the wave form at the point Q 1 is inverted by the inverter 35 and thus the wave form of the inverter output is as shown in FIG. 5C. Through the action of the capacitor 37, a wave form as shown in FIG. 5D appears at the point Q 2 . The wave form of FIG. 5D is inverted by the inverter 40, so that the output of the inverter 40 becomes `0` as shown in FIG. 5E. The wave form of FIG. 5E is further inverted by the inverter 41, so that the output of the inverter 41, i.e. a wave form at the output point Q 3 , becomes `1` as shown in FIG. 5F. The signal `1` shown in FIG. 5F is applied to the other input of the AND gate 27. When the signal O 2 is `0`, the output of the AND gate 27 becomes `1` and the output of the inverter 32 becomes `0`, so that the relay 15 is energized and the switch 7 is closed. When signal O 2 is `1`, the output of the AND gate 27 is 10` and the output of the inverter 32 is `1`, and therefore the relay 15 is deenergized to open the switch 7. At end of the period T 1 , the AC signal becomes 10` and this state continues for the period T 2 . This state corresponds to a situation that the apparatus shown in FIG. 1 can not be controlled normally. Specifically, the output level of the flip-flop circuit 25b remains "0". During the period T 2 , the capacitor 33 is gradually charged from time t o by the power source +V DD , as shown in FIG. 5B, and thus the potential at the point Q 1 gradually increases from time t o and becomes higher than the threshold voltage V TH1 of the inverter 35 at time t 1 . Accordingly, the output of the inverter 35 changes from "1" to "0" at time t 1 . Accordingly the potential at point Q 2 gradually decreases from time t 1 and becomes lower than the threshold voltage V TH2 of the inverter 40 at time t 2 . As the result, the output of the inverter 40 changes from "0" to "1" at t 2 as shown in FIG. 5E. Also, the output of the inverter 41 changes from `1` to `0` at time t 2 , as shown in FIG. 5F. So long as the voltage at the output terminal Q 3 is `0`, the output of the AND gate 27 is `0` and the output of the inverter 32 is `1`. As a result, the relay 15 is deenergized and switch 7 is forcibly opened. In other words, the switch 7 keeps its off state irrespective of the level at output O 2 , so that the apparatus shown in FIG. 1 is completely protected.
In FIGS. 5A to 5F, the AC signal is at `0` level at time t o and the `0` level is kept during period T 2 . In FIGS. 6A to 6F, there are shown wave forms at the respective portions when `1` level is kept during period T 2 from time t o . The wave forms shown in FIGS. 6A to 6C may be readily understood and therefore explanation of them will be omitted. Explanation will be given only about the wave forms shown in FIGS. 6D to 6F. As shown in FIG. 6D, a potential at point Q 2 gradually decreases from `1` immediately before time t o to be below the threshold voltage V TH2 of the inverter 40 at time t 2 . Accordingly, output of the inverter 40 is inverted from `0` to `1` at time t 2 and the output of the inverter 41 is inverted from `1` to `0` at time t 2 . Therefore, during the period T 2 , the switch 7 is opened irrespective of the level of the signal O 2 .
As described above, when an apparatus, e.g. an air heating apparatus, is subjected to an abnormal control due to a fault of the pulse generator 13 or the microcomputer 12, the operation of the air heating apparatus may be forcibly stopped so that dangerous accident such as fire or explosion may be prevented. The controlled apparatus to which the invention is applied is not always limited to the air heating apparatus.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
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A control circuit using a microprocessor comprises a time counting circuit; a main control logic circuit receiving a time signal from the time counting circuit; and an AC signal generator receiving a first signal from the time counting circuit and a second signal from the main control logic circuit. When the microprocessor is out of order, the AC signal takes continuous "1" or "0" level. The control circuit further comprises a detecting circuit for detecting an abnormal state of the AC signal and a control circuit for maintaining an apparatus to be controlled by the control circuit in a predetermined safe state when the detecting circuit detects the abnormal state of the AC signal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The contents of this application are related to a provisional application having serial No. 60/371,063 filed on Apr. 8, 2002, the contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to security tags in general, and in particular to a tag body containing an attaching means for use in electronic article surveillance (EAS) tags.
BACKGROUND OF THE INVENTION
[0003] Various types of electronic article surveillance (EAS) systems are known having the common feature of employing a marker or tag which is affixed to an article to be protected against theft, such as merchandise in a store. When a legitimate purchase of the article is made, the marker can either be removed from the article, or converted from an activated state to a deactivated state. Such systems employ a detection arrangement, commonly placed at all exits of a store, and if an activated marker passes through the detection system, it is detected by the detection system and an alarm is triggered.
[0004] For example, U.S. Pat. No. 5,426,419 to Nguyen et al., and assigned to Sensormatic Electronics Corporation, discloses an EAS tag having an arcuate channel that extends from an opening thereof to the actual attaching assembly and the detaching mechanism thereof. The channel increases the susceptibility of defeat of the attaching assembly because it guides an object that is inserted by an unauthorized individual directly to the attaching assembly and allows disengagement thereof.
[0005] U.S. Pat. No. 6,373,390 to Hogan et al., assigned to the same assignee as the '419 patent, is an improvement patent issued in light of the shortcomings of the '419 patent. The '390 patent admits that the EAS tag of the '419 patent “can be defeated by insertion of a segment of relatively rigid metal bent in an arcuate manner to simulate the arcuate probe of the associated detacher device.” Furthermore, the '390 patent describes a fish tape which may be formed to resemble the requisite arcuate probe in order to defeat the EAS tag of the '419 patent, “the formed fish tape 50 is strong enough to hold its form when pushed into arcuate channel 7 until it can be manipulated into and against member 6 , which then can be rotated to release tack assembly 4 .”
[0006] With respect to the '419 and '390 patent, many free standing arcuate probes have been either manufactured or misappropriated by unscrupulous individuals by dismantling the detacher components with which the probes are associated. The arcuate probe is inserted into the arcuate channel by hand and is lead directly to the preventing mechanism. In the '390 device, the arcuate channel leads the manipulated arcuate probe to the opening or slot located in the arcuate channel, wherein the opening further aligns and guides the hand manipulated probe directly to the preventing mechanism or member. In addition, the force required to release the preventing mechanism of the '419 and '390 device is less than the force required to release the preventing mechanism of the instant invention. Accordingly, an unscrupulous individual may easily defeat the preventing mechanism of the '419 and '390 devices by manipulating an illicitly acquired freestanding arcuate probe.
[0007] The '419 and '390 devices may be defeated by penetrating the bottom housing in proximal relation to the preventing mechanism and inserting a rigid and elongated element and forcing metal clip to rotate, whereby the preventing mechanism will release the pin. The instant device is more difficult to defeat in this manner.
[0008] In addition, the preventing mechanism of the '419 and '390 patents is attached on only one end thereof, thus allowing movement out of the horizontal plane. Consequently, the vertical movement of the clamp increases the susceptibility of defeat of the attaching assembly because the jaws expand more easily because the angle of the clamp varies between the first end and second end as a result of the vertical movement of the non-secure end. The pull force to disengage a pin from the instant device and the '419 device was conducted by using an Imada product model DPS220R, obtainable from 450 Skikie Blvd. #503, N. Brook, Ill. 60062.
[0009] The prior art does not address the need for an EAS tag that is difficult to defeat. In addition, the prior art fails to provide a clamp assembly that requires greater pull force to disengage a pin from the clamp assembly. Furthermore, the prior art fails to provide a tag that is more difficult to defeat even when an unscrupulous individual has illicitly acquired a freestanding arcuate probe. Therefore, there remains a long standing and continuing need for an advance in the art of EAS tags that is more difficult to defeat, is simpler in both design and use, is more economical, efficient in its construction and use, and provides a more secure engagement of the article.
SUMMARY OF THE INVENTION
[0010] Accordingly, it is a general object of the present invention to overcome the disadvantages of the prior art.
[0011] Therefore, it is a primary objective of the invention to provide an EAS tag that is more difficult to defeat.
[0012] It is another objective of the invention to provide a cost-efficient EAS tag.
[0013] It is another objective of the invention to provide an EAS tag that is durable.
[0014] It is yet another objective of the invention to provide an EAS tag that does not have an arcuate channel that may be used to guide an unauthorized detaching probe to the attaching member.
[0015] It is a further objective of the invention to provide an EAS tag that is detachable when used with an authorized detaching unit.
[0016] In keeping with the principles of the present invention, a unique EAS tag is disclosed wherein no channel is defined therein that will guide an unauthorized probe to the attaching member. The interior of the tag further has numerous partitions and pillars that will prevent insertion of the unauthorized probe if inserted in the wrong plane. In addition, the EAS tag will deflect the unauthorized probe into false paths.
[0017] The EAS tag of the instant invention also discloses a metal clip that has an attaching region for receiving a shaft of a pin securely therein. The pin is removable when an authorized detacher is used to insert a probe into an opening within the EAS tag, and as a result of the secure fit of the tag within the detacher's nesting portion, the probe guides itself to the attaching member and applies a force thereto. The clip is slideably mounted onto at least one track that causes the clip to travel in a linear motion and causing the attaching region to release a shaft of the pin.
[0018] Furthermore, an apex region of the EAS tag that encloses the attaching member has a honeycombed shape such that unauthorized probes cannot be inserted into holes created above the attaching member to manipulate the same.
[0019] Such stated objects and advantages of the invention are only examples and should not be construed as limiting the present invention. These and other objects, features, aspects, and advantages of the invention herein will become more apparent from the following detailed description of the embodiments of the invention when taken in conjunction with the accompanying drawings and the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] It is to be understood that the drawings are to be used for the purposes of illustration only and not as a definition of the limits of the invention. In the drawings, wherein similar reference characters denote similar elements throughout the several views:
[0021] [0021]FIG. 1 is a side elevational view of the tag of the instant invention in an assembled state.
[0022] [0022]FIG. 2 is a side elevational view of the tag of the instant invention in an unassembled state.
[0023] [0023]FIG. 3 is a perspective exploded view of the tag of the instant invention and the components thereof.
[0024] [0024]FIG. 4 is a top plan view of the interior of second half of the instant tag with the tracks installed.
[0025] [0025]FIG. 5 is a top plan view of the interior of second half of the instant tag with the tracks and the attaching member installed.
[0026] [0026]FIG. 6 is a top plan view of the interior of first half of the instant tag illustrating an alternate preferred embodiment for accommodating an alternate resilient member.
[0027] [0027]FIG. 7 is a top plan view of the interior of second half of the instant tag illustrating an alternate preferred embodiment for accommodating an alternate resilient member that attaches to first half illustrated in FIG. 6.
[0028] [0028]FIG. 8 is a top plan view of the interior of first half of the instant tag illustrating an alternate preferred embodiment for accommodating an alternate resilient member.
[0029] [0029]FIG. 9 is a top plan view of the interior of second half of the instant tag with the attaching member installed illustrating an alternate preferred embodiment for accommodating an alternate resilient member that attaches to first half illustrated in FIG. 8.
[0030] [0030]FIG. 10 is a perspective view of the interior of first half of the instant invention.
[0031] [0031]FIG. 11 is a perspective view of the interior of second half of the instant invention without the components therein.
[0032] [0032]FIG. 11A is a perspective view of the interior of second half of the instant invention with the tracks and attaching member installed.
[0033] [0033]FIG. 12 is a perspective view of a pin used with the instant invention.
[0034] [0034]FIG. 12A is a frontal perspective view of the attaching member of the instant invention.
[0035] [0035]FIG. 12B is a front elevational view of the attaching member of the instant invention.
[0036] [0036]FIG. 12C is a side perspective view of the attaching member of the instant invention.
[0037] [0037]FIG. 12D is a top perspective view of the first and second tracks used in the instant invention.
[0038] [0038]FIG. 13 is a top plan view of the interior of the first half of an alternate preferred embodiment of the instant invention illustrating additional pillars and walls that may be placed within the tag to thwart an unauthorized probe insertion.
[0039] [0039]FIG. 13A is a top plan view of the interior of the second half of an alternate preferred embodiment of the instant invention illustrating additional pillars and walls that may be placed within the tag to thwart an unauthorized probe insertion that attaches to first half illustrated in FIG. 13.
[0040] [0040]FIG. 14 is a top plan view of the interior of the first half of an alternate preferred embodiment of the instant invention illustrating additional pillars that may be placed within the tag to thwart an unauthorized probe insertion.
[0041] [0041]FIG. 14A is a top plan view of the interior of the second half of an alternate preferred embodiment of the instant invention illustrating additional pillars that may be placed within the tag to thwart an unauthorized probe insertion and attaches to the first half illustrated in FIG. 14.
[0042] [0042]FIG. 15 is an electrical schematic diagram of the resonant tag circuit.
[0043] [0043]FIG. 16 is a perspective view of the resonant tag circuit.
[0044] [0044]FIG. 17 is a block diagram of an article surveillance system incorporating the resonant tag circuit.
[0045] [0045]FIG. 18 is a cross-sectional view of a resonant tag system taken along line 18 - 18 of FIG. 16.
DETAILED DESCRIPTION OF THE INVENTION
[0046] Referring now to FIGS. 1 and 2, a tag 20 is illustrated having a first half 22 and a second half 24 . First and second halves 22 and 24 are preferably made of a hard or rigid material. A usable rigid or hard material might be a hard plastic such as, for purposes of illustration but not limitation, an injection molded ABS plastic. If a plastic material is used, the mating of a first side wall 26 to a second side wall 28 can accomplished via an ultrasonic weld or like joining mechanism. However, it is to be understood that other joining methods, such as adhesives, may also be used. When first half 22 and second half 24 are securely joined, first sidewall 26 and second sidewall 28 form a peripheral outer wall of tag 20 . Second half 24 has an apex region 25 that extends therefrom in an opposing direction to first half 22 .
[0047] Now referring to FIGS. 3, 4, 5 , 11 , and 11 A, an exploded perspective view, top plan view, and perspective views illustrate the interior of second half 24 . Second half 24 receives at least a first track 30 therein, and in a preferred embodiment it also receives a second track 32 . First track 30 is tightly received within at least a first slot 31 and second track 32 is received tightly within at least a second slot 33 , such that tracks 30 and 32 are maintained in substantially parallel relations. Tracks 30 and 32 are made of a hard material such as, but not limited to, metal, which enhances the durability and performance of the tag 20 .
[0048] An attaching member 34 , as described in greater detail hereinafter, slideably rests on at least first track 30 , but in a preferred embodiment, rests on both first and second tracks 30 and 32 . Attaching member 34 has a resilient member 36 that normally maintains an opening 38 defined on said attaching member 34 in axial alignment with an aperture 40 defined on the inside of second half 24 and a hole 42 defined on the interior of first half 22 . In one preferred embodiment, attaching member 34 is made of spring sheet metal. Resilient member 36 may be a resilient lever arm 43 and in an alternate preferred embodiment, as illustrated in FIGS. 7 and 9, at least one spring 44 may be substituted for the resilient lever arm 43 . Resilient member 36 is maintained in proximal relations to a barrier 45 , such that attaching member 34 is maintained in axial alignment described above.
[0049] Now referring to FIGS. 6, 8, and 10 , the interior of first half 22 is illustrated having a reinforcement means 46 defining opening 42 . Reinforcement means 46 extends inwardly but does not interfere with the sliding action of attaching member 34 on first and second tracks 30 and 32 . At least a first ridge 48 extends inwardly from the interior of first half 22 and is in proximal relation to first track 30 . In a preferred embodiment, a second ridge 50 also extends inwardly from the interior of first half 22 and is in proximal relation to second track 32 . Ridges 48 and 50 prevent upward movement of attaching member 34 , yet do not interfere with the sliding arrangement of attaching member 34 over first and second tracks 30 and 32 . Ridges 48 and 50 are in substantially parallel relations to one another.
[0050] Now referring to FIG. 12 and FIGS. 11 and 11A again in particular, in addition to the previous FIGS, a plurality of devices have been provided to prevent unauthorized manipulation and disengagement of attaching member 34 . When first half 22 and second half 24 are assembled, a shaft 52 , having a plurality of indentations 54 at predetermined intervals along the length thereof, is inserted through hole 42 and is received securely yet removably within opening 38 of attaching member 34 . Shaft 52 further extends into aperture 40 , which is defined by a tubular formation 41 extending inwardly from second half 24 . A top 55 is securely maintained at one end of shaft 52 , such that an opposing end of shaft 52 traverses an article to be monitored and is maintained within opening 38 of attaching member 34 and aperture 40 , whereby the article is securely bound between top 55 and outer surface of tag 20 .
[0051] Now also referring to FIGS. 12A, 12B, and 12 C, attaching member 34 has a forward edge 75 and a distal rearward edge 77 . An attaching region 78 is defined proximal to the forward edge 75 and resilient member 36 is located proximal to rearward edge 77 . A first region 80 and a second region 82 are divided by attaching region 78 . A first lip 84 extends downwardly from first region 80 and a second lip 86 extends downwardly from second region 82 , such that first lip 84 and second lip 86 are in substantially parallel relations to one another, and each of the lips 84 and 86 are in substantially perpendicular relation to first and second regions 80 and 82 respectively. A first interior wall 88 and a second interior wall 90 are created by lips 84 and 86 respectively. First lip 84 and second lip 86 extend beyond rearward edge 77 and form a first outward curve 92 and a second outward curve 94 respectively, on a side of attaching member 34 proximal to resilient member 36 . Opening 38 of attaching member 34 is defined by a first jaw 96 and an opposing second jaw 98 . Jaws 96 and 98 extend downwardly from the plane of first and second regions 80 and 82 and are in proximal relations when they define opening 38 . However, jaws 96 and 98 are flexible such that they can move towards one another to decrease the size of opening 38 or they can move away from one another to increase the size of opening 38 . As a result, shaft 52 is maintained within opening 38 as defined by jaws 96 and 98 in a secure, yet removable, manner.
[0052] Now also referring to FIG. 12D, first track 30 has a first top edge 100 and a first bottom edge 104 which are distal to one another and are interconnected by a first front edge 108 and an opposing first back edge 112 . Second track 30 has a second top edge 102 and a second bottom edge 106 which are distal to one another and are interconnected by a second front edge 110 and an opposing second back edge 114 . First back edge 112 and second back edge 114 are curved to accommodate the curved portion of second side wall 28 where apex 25 is created. First track 30 has a first outer surface 116 and a first inner surface 120 and second track 32 has a second outer surface 118 and a second inner surface 122 .
[0053] In order to disengage shaft 52 from jaws 96 and 98 , enough force must be applied to forward edge 75 of attaching member 34 to overcome the force exerted by the resilient member 36 , and to move attaching member 34 towards rearward edge 75 . In addition, the force must be sufficient to overcome the frictional force created between first interior wall 88 and second outer surface 118 and the frictional force created between second interior wall 90 and first outer surface 116 . In order to do so, a probe of a predetermined shape and length must be inserted through entrance 56 of tag 20 and extend to attaching member 34 to apply the sufficient necessary force to forward edge 75 to overcome the force exerted by the resilient member 36 and the frictional force described above to allow sufficient linear movement along first and second tracks 30 and 32 to disengage and remove shaft 52 from first and second jaws 96 and 98 . U.S. Pat. No. 4,738,258 is hereby incorporated by reference for teaching the probe required and the necessary actuation thereof for insertion into entrance 56 . U.S. Pat. No. 4,738,258 can be modified into the disengagement apparatus illustrated in U.S. Pat. No. 5,426,419 and U.S. Pat. No. 5,535,606, the teachings of the detacher are also incorporated herein by reference.
[0054] To determine the force required to disengage the shaft 52 from jaws 96 and 98 of attaching member 34 of the instant invention as compared to the tag of the '419 patent, the following experiment was conducted on ten tags 10 of the instant invention and ten tags produced in accordance with the specification of the '419 patent. A spring balance was hung on a wall, with its spring loading hook at the bottom. Two ends of a cotton sling were tied to form a loop. One end of the loop was secured on the hook of the balance whereas the other end was wound through the handle such that a downward pull force on the detacher (as illustrated in FIGS. 11 and 12 of the '419 patent) led to the squeezing of the detacher's trigger. Because the spring balance is in series with the sling, a measure of the triggering force to detach the tack shaft 52 could be measured. On average, approximately five pounds more force was required to detach the shaft 52 from the attaching member 34 of the instant invention than the tag of the '419 patent.
[0055] In order to defeat the introduction of unauthorized probes into entrance 56 , several false paths and barriers are provided within tag 20 and the arcuate channel of the '419 patent and the '390 patent are completely eliminated. Because apex region 25 of tag 20 is constructed to be securely retained within a nesting or cradle area of a detacher, as taught by the '419 patent, tag 20 does not require any arcuate channels to lead the detaching probe to the forward edge 75 of the attaching member 34 . The predetermined shape of the detaching probe and the predetermined positioning of the attaching member 34 allow an authorized individual using an authorized detacher to disengage the shaft 52 from jaws 96 and 98 , thereby releasing the attached article. Dashed line 99 , of FIG. 5, illustrates a proper path that may be taken by the detaching probe.
[0056] However, to defeat even the introduction of a probe that has been illicitly disassembled from an authorized detacher, a first partition 58 prevents entrance of the unauthorized probe if at an incorrect plane. A second partition 60 having a greater height than first partition 58 , also prevents the introduction of an unauthorized probe to attaching member 34 . A first pillar 62 and a second pillar 64 also prevent application of force to attaching member 34 by an unauthorized probe by deflecting the same. A third partition 66 , a fourth partition 68 , a fifth partition 70 , and sixth partition 72 are at different levels and define a plurality of cavities 74 therebetween. Cavities 74 extend within apex region 25 and are substantially perpendicular to the plane of attaching member 34 , such that an unauthorized probe inserted through apex region 25 will be retained within a single cavity 74 and will not be able to manipulate attaching member 34 laterally to disengage shaft 52 .
[0057] Furthermore, if an unauthorized probe is being manipulated by hand, the probe will not be inserted at the correct plane to make proper contact with forward edge 75 of attaching member 34 to disengage the same. Instead, the unauthorized probe will go into the space defined between attaching member 34 and the different partitions 66 , 68 , 70 , and 72 . FIGS. 13 and 13A teach an alternate preferred embodiment with different barriers to prevent access to the attaching member 34 of tag 20 . FIGS. 14 and 14A teach an alternate preferred embodiment with further different barrier arrangements to prevent access to the attaching member 34 of tag 20 .
[0058] Referring now also to FIG. 15, therein is illustrated a schematic diagram of a resonant tag circuit 124 . In a preferred embodiment, circuit 124 has at least an inductive element 126 and at least a capacitance element 128 connected in a series loop and forming an inductive capacitance (LC) resonant circuit 124 . The resonant tag circuit is employed in connection with electronic article security systems particularly electronic article security systems of the radio frequency or RF electromagnetic field type. Such electronic article security systems are well known in the art and a complete detailed description of the structure and operation of such electronic article security systems is consequently not necessary for an understanding of the present invention.
[0059] However, as illustrated in FIG. 17, such electronic article security systems employing resonant tag circuits include a transmitting means 130 for transmitting electromagnetic energy at or near the resonant frequency of the resonant tag into or through a surveillance zone 132 . A detecting means 134 monitors the surveillance zone 132 for the presence of a resonant tag within the surveillance zone 132 . Surveillance zone 132 is generally proximate to an entrance and/or exit of a facility such as, but not limited to, a retail store. The security system's function is to detect the presence within the surveillance zone 132 a monitored article having a resonant tag circuit 124 attached thereto in a secure fashion.
[0060] In such a system, transmitting means 130 transmits pulses in the form of RF bursts at a frequency in the low radio-frequency range, such as 58 kHz in a preferred embodiment but may be adapted to be at any appropriate frequency as desired. The pulses (bursts) are emitted (transmitted) at a repetition rate of, for example 60 Hz AC cycle, with a pause between successive pulses. The detecting means 134 includes a receiver 136 which is synchronized (gated) with the transmitting means 130 so that it is activated only during the pauses between the pulses emitted by the transmitting means 130 . The receiver 136 expects to detect nothing in these pauses between the pulses. If an activated tag is present within the surveillance zone 132 , however, the resonator therein is excited by the transmitted pulses, and will be caused to oscillate at the transmitter frequency, i.e., at 58 kHz in the above example. The resonator emits a signal which rings at the resonator frequency, with an exponential decay time (“ring-down time”). The signal emitted by the activated tag, if it is present between transmitting means 130 and the receiver 136 , is detected by the receiver 136 in the pauses between the transmitted pulses and the receiver accordingly triggers an alarm 138 . Alarm 138 may be audible and/or visual or can be a silent alarm that is detected by any means known in the art.
[0061] In a preferred embodiment, to minimize false alarms, the detecting means 134 usually must detect a signal in at least two, and preferably four, successive pauses; however, it is to be understood that the present invention can be adapted to function within one pause. Furthermore, in order to further minimize false alarms, such as due to signals produced by other RF sources, the receiver 136 employs two detection windows within each pause. The receiver 136 integrates any 58 kHz signal (in this example) which is present in each window, and compares the integration results of the respective signals integrated in the windows. Since the signal produced by the tag is a decaying signal, if the detected signal originates from a resonator in a tag it will exhibit decreasing amplitude (integration result) in the windows. By contrast, an RF signal from another RF source, which may coincidentally be at, or have harmonics at, the predetermined resonant frequency, would be expected to exhibit substantially the same amplitude (integration result) in each window. Therefore, alarm 138 is triggered only if the signal detected in both windows in a pause exhibits the aforementioned decreasing amplitude characteristic in each of a number of successive pauses.
[0062] For this purpose, as noted above, the receiver electronics is synchronized by a synchronization circuit with the transmitter electronics. The receiver electronics is activated by the synchronization circuit to look for the presence of a signal at the predetermined resonant frequency in a first activation window of about 1.7 ms after the end of each transmitted pulse. For reliably distinguishing the signal (if it originated from the resonator) integrated within this first window from the signal integrated in the second window, a high signal amplitude is desirable in the first window. Subsequently, the receiver electronics is deactivated, and is then re-activated in a second detection window at approximately 6 ms after the original resonator excitation, in order to again look for and integrate a signal at the predetermined resonant frequency. If such a signal is integrated with approximately the same result as in the first detection window, the evaluation electronics assumes that the signal detected in the first window did not originate from a marker, but instead originated from noise or some other external RF source, and alarm 138 therefore is not triggered.
[0063] Now also referring to FIGS. 16 and 18, therein is illustrated a preferred embodiment of the resonant tag circuit 124 . Inductive element 126 is formed by a conducting member 140 that is made of any material that is capable of conducting electricity, and in a preferred embodiment is made of copper. Conducting member 140 is coiled around a first member 142 that is preferably constructed of a non-conductive material such as, but not limited to, plastic and rubber. First member 142 has a first wall 144 and a second wall 146 that are interconnected by a middle portion 148 . First wall 144 , second wall 146 , and middle portion 148 axially define a cavity 150 extending therethrough.
[0064] Middle portion 148 is adapted to receive conducting member 140 thereon in a coiled fashion on an outer surface 152 thereof between first wall 144 and second wall 146 . Middle portion 148 has an inner surface 154 that defines cavity 150 . A magnetic member 156 is adapted to be received within cavity 150 and to be frictionally retained within inner surface 154 of middle portion 148 . Magnetic member 156 may be a ferromagnetic material or any other material having magnetic properties, and in a preferred embodiment, magnetic member 156 is made of amorphous metals.
[0065] Capacitance element 128 is a parallel plate capacitor formed of conductive material on a first plate and a second plate (not shown) that are known in the art. Capacitance element 128 is adapted to be received on first member 142 , and in a preferred embodiment is received on first wall 144 thereof. First plate and second plate of capacitance element 128 are attached to opposing ends of conducting member 140 to form a series circuit.
[0066] When resonant tag circuit 124 enters a surveillance zone 132 it is subjected to an electromagnetic field and magnetic member 156 is charged. As the electromagnetic field is removed, the stored magnetic energy stored in the magnetic member 156 is released and thus an ac current is generated within inductive element 126 and capacitance element 128 . When an ac voltage is applied to the resonant tag circuit 124 , the current depends on the frequency thereof. The resonant frequency of circuit 124 can be determined by the following equation:
fo = 1 2 π LC
[0067] Wherein f o is the resonant frequency of the circuit and L is the inductance and C is the capacitance. As can be ascertained from the equation, many possible combinations yield the desired resonant frequency, however, the L to C ratio is preferably kept high in order for the circuit to be selective and minimize undesirable resonances to disturbances close to the resonant frequency thus minimizing false alarms. In a preferred embodiment, optimal values were determined to be L=2.08 mH and C=3.6 nF thus yielding an L to C ratio of 577,777.78.
[0068] It is to be understood that resonant tag circuit 124 is of sufficient size to be stored within casings used in article surveillance systems. Specifically, tag circuit 124 is of sufficient size to be received and enclosed within compartment 76 of tag 20 . Compartment 76 is defined by a peripheral wall 158 extending inwardly from second half 24 to enclose the resonant tag circuit 124 therein. A false path 160 is created between second side wall 28 and peripheral wall 158 .
[0069] If an article having resonant tag circuit 124 attached thereto via tag 20 is moved into the surveillance zone 132 , the alarm 138 will be activated by circuit 124 to signify unauthorized removal of the article through a specified area. For purposes of illustration but not limitation, in a preferred embodiment, the length of circuit 124 is less than 2 cm and the radius thereof is less than 1 cm. However, it is to be understood that alternate sizes and shapes of circuit 124 will also function as taught and alternate electronic detection circuits as are known in the art may also be used.
[0070] While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible without departing from the essential spirit of this invention. Accordingly, the scope of the invention should be determined not by the embodiment illustrated, but by the appended claims and their legal equivalents.
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An electronic article surveillance (EAS) tag 20 having a metal attaching member 34 located therein and adapted to securely and releasably receive a shaft 52 of a pin therein, whereby a predetermined arcuate probe is inserted through an opening and applies a requisite force to the attaching member 34 to release the shaft 52. There are no channels leading the authorized arcuate probe to the attaching member 34. A plurality of partitions 58 and pillars 62 are interspersed within tag 20 to deflect any unauthorized probes from engaging and detaching attaching member 34.
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REFERENCE TO PRIORITY APPLICATION
[0001] This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 2006-101966, filed Oct. 19, 2006, the entire contents of which are hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to memory devices and methods of forming same and, more particularly, to non-volatile memory devices and methods of forming non-volatile memory devices.
BACKGROUND OF THE INVENTION
[0003] Semiconductor memory devices are generally classified as volatile memory devices and nonvolatile memory devices. Volatile memory devices lose stored data when power is turned off, but nonvolatile memory devices retain stored data even after power is turned off. Flash memory devices, like general nonvolatile memory devices, can be classified into a floating gate type and a charge trap type, depending on the kinds of data storage layers constituting a unit cell.
[0004] FIG. 1 is a partial schematic perspective view of a floating gate type flash memory device, illustrating a relationship between a floating gate voltage (Vfg) and parasitic capacitances (C FGA , C FGW ). Referring to FIG. 1 , a tunnel oxide layer 17 , a floating gate 19 , an inter-gate insulating layer 27 and a control gate 29 are sequentially formed over an active region 9 to thereby define a device isolation layer 13 formed on a semiconductor substrate 1 . Here, the inter-gate insulating layer 27 may be formed as an oxide-nitride-oxide (ONO) layer. The active region 9 extends in a first direction (DA), which is a bitline direction, and the control gate 29 extends in a second direction (DW), which is a word line direction. An interlayer insulating layer 27 is interposed between the floating gates 19 , as illustrated.
[0005] Reference symbols V and C illustrated in FIG. 1 show voltage and capacitance references. V FG denotes a voltage of the floating gate disposed in a central position (hereinafter, the central floating gate) among nine floating gates. V A denotes voltages of the floating gates adjacent in the first direction (DA) with respect to the central floating gate, and V W denotes voltage of the floating gate adjacent in the second direction (DW) with respect to the central floating gate. C FGA denotes a parasitic capacitance caused between the floating gates adjacent in the first direction (DA), and C FGW denotes a parasitic capacitance caused between the floating gates adjacent in the second direction (DW). As understood by those skilled in the art, the parasitic capacitances increase as the high integration of the memory devices is increased. As a distance between the active region 9 and an inter-gate insulating layer 27 is shortened, charges in the active region 9 may be trapped in the inter-gate insulating layer 27 and cause malfunction of a memory cell. Therefore, reliability and operational characteristics of the memory device may be degraded.
SUMMARY OF THE INVENTION
[0006] Embodiments of the present invention include non-volatile memory devices that are configured to have reduced parasitic capacitance between floating gate electrodes. According to some of these embodiments, a non-volatile memory device is provided having a substrate with first and second semiconductor active regions therein. These active regions are separated from each other by a trench isolation region, which has a recess therein that extends along its length. First and second floating gate electrodes are also provided. These first and second floating gate electrodes extend on the first and second semiconductor active regions, respectively. A control electrode is provided that extends between the sidewalls of the first and second floating gate electrodes and into the recess in the trench isolation region. In particular, the recess in the trench isolation region is sufficiently deep so that the control electrode, which extends into the recess, operates to reduce (e.g., block) a parasitic coupling capacitance between the sidewalls of the first and second floating gate electrodes. For example, the recess may be sufficiently deep so that a first portion of the trench isolation region extends between a first sidewall of the control electrode (in the recess) and a sidewall of the first floating gate electrode and a second portion of the trench isolation region extends between a second sidewall of the control electrode (in the recess) and a sidewall of the second floating gate electrode.
[0007] According to aspects of these embodiments, a first sidewall of the trench isolation region defines an interface with a first sidewall of the first floating gate electrode and a width of the first floating gate electrode is tapered to be narrower at its top relative to its bottom. According to additional aspects of these embodiments, a width of the first floating gate electrode is greater than a width of the first semiconductor active region.
[0008] According to additional embodiments of the invention, a non-volatile memory device is provided with a semiconductor substrate having a trench therein that is at least partially filled with an electrically insulating trench isolation region. The trench isolation region has a trench-shaped recess therein that extends along its length. A first floating gate electrode extends on a first portion of the semiconductor substrate extending adjacent the trench isolation region and a control electrode is provided that extends in the trench-shaped recess and on the first floating gate electrode. A second floating gate electrode is also provided on a second portion of the semiconductor substrate, which extends adjacent the trench isolation region. According to aspects of these embodiments, the first and second floating gate electrodes have opposing sidewalls and a center of the trench-shaped recess is located about equidistant from the opposing sidewalls.
[0009] Still further embodiments of the present invention include methods of forming non-volatile memory devices. Some of these methods include forming first and second trench isolation regions at side-by-side locations in a semiconductor substrate to thereby define a semiconductor active region therebetween. A floating gate electrode is formed on an upper surface of the semiconductor active region and an electrically insulating layer is formed on sidewalls and an upper surface of the floating gate electrode. The electrically insulating layer is etched back to define sidewall insulating spacers on sidewalls of the floating gate electrode. The upper surfaces of the first and second trench isolation regions are selectively etched-back to define trench-shaped recesses therein. This etching step is performed using the sidewall insulating spacers as an etching mask. These methods also include removing the sidewall insulating spacers to expose the sidewalls of the floating gate electrode and etching back the sidewalls of the floating gate electrode for a sufficient duration so that the floating gate electrode is tapered to be narrower at its top relative to its bottom. Alternative methods may also include removing the sidewall insulating spacers to expose the sidewalls of the floating gate electrode and lining the trench-shaped recesses with an inter-gate dielectric layer. The trench-shaped recesses are filled with portions of a control electrode, which operates to block parasitic capacitance (in the word line direction) between adjacent floating gate electrodes.
[0010] Still further embodiments of the invention include forming a mask pattern on a surface of a semiconductor substrate and selectively etching the surface of the semiconductor substrate to thereby define first and second trenches at side-by-side locations in the semiconductor substrate, using the mask pattern as an etching mask. The first and second trenches and openings in the mask pattern are then filled with first and second trench isolation regions, respectively. The mask pattern is removed to expose sidewalls of the first and second trench isolation regions. The exposed sidewalls of the first and second trench isolation regions are then recessed. First and second floating gate electrodes are formed against the recessed sidewalls of the first and second trench isolation regions, respectively. The upper surfaces of the first and second trench isolation regions are etched-back to expose sidewalls of the first and second floating gate electrodes. An electrically insulating layer is formed on the exposed sidewalls and upper surfaces of the first and second floating gate electrodes. The electrically insulating layer is then etched back to define sidewall insulating spacers on sidewalls of the first and second floating gate electrodes. Upper surfaces of the first and second trench isolation regions are then selectively etched to define trench-shaped recesses therein. This etching step uses the sidewall insulating spacers as an etching mask. According to some additional embodiments of the invention, the sidewall insulating spacers are removed to expose the sidewalls of the floating gate electrode and the sidewalls of the floating gate electrode are etched back for a sufficient duration so that the floating gate electrode is tapered to be narrower at its top relative to its bottom.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of a non-volatile memory device having an array of floating gate electrodes therein that are capacitively coupled together in a word line direction (DW) and a bit line direction (DA).
[0012] FIG. 2 is a cross-sectional view of a non-volatile memory device according to an embodiment of the present invention.
[0013] FIG. 3 is a cross-sectional view of a non-volatile memory device according to an embodiment of the present invention.
[0014] FIG. 4 is a cross-sectional view of a non-volatile memory device according to an embodiment of the present invention.
[0015] FIGS. 5-11 are cross-sectional views of intermediate structures that illustrate additional methods of forming the non-volatile memory device of FIG. 2 .
[0016] FIG. 12 is a cross-sectional view of an intermediate structure that illustrates fabrication steps associated with the manufacture of the non-volatile memory device of FIG. 3 .
[0017] FIGS. 13-15 are cross-sectional views of intermediate structures that illustrate additional methods of forming the non-volatile memory device of FIG. 3 .
[0018] FIGS. 16-20 are cross-sectional views of intermediate structures that illustrate methods of forming the non-volatile memory device of FIG. 4 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] Preferred embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be constructed 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 present invention to those skilled in the art.
[0020] It will be understood that, although the terms first, second and the like may be used herein to describe various regions, layers, and the like, these regions, layers, and the likes should not be limited by these terms. These terms are only used to distinguish one region, layer, and the like from another region, layer, and the like. It will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or a third layer between intervening layers may also be present. In the drawings, the thicknesses of layers and regions may be exaggerated for clarity.
[0021] FIG. 2 is a cross-sectional view of a nonvolatile memory device according to an embodiment of the present invention, taken along a word line direction. Referring to FIG. 2 , a device isolation layer 113 in a semiconductor substrate 101 defines active regions 109 of the device. This device isolation layer 113 is illustrated as including a plurality of trench isolation regions that fill respective trenches 107 . A gate insulating layer 117 and a floating gate electrode 119 are formed on the active region 109 . A width of the floating gate 119 may be greater than an upper surface of the active region 109 . The gate insulating layer 117 may be formed as a tunnel oxide layer.
[0022] The device isolation layer 113 may include a lower insulating pattern 111 and an upper insulating pattern 112 . The lower insulating pattern 111 and the upper insulating pattern 112 may be formed of materials having different electrical, chemical or other physical characteristics. For example, the lower insulating pattern 111 may include a material having excellent gap-filling performance and the upper insulating pattern 112 may include a material that is highly resistant to wet etching using an etchant such as phosphoric acid and/or hydrofluoric acid.
[0023] The upper insulating pattern 112 includes a recess region 125 disposed between the floating gates 119 . As illustrated, the upper insulating pattern 112 is interposed between sidewalls of the recess region 125 and the floating gate 119 (or gate insulating layer 117 ). A bottom surface of the upper insulating pattern 112 may be lower than that of the gate insulating layer 117 and a bottom surface of the recess region 125 may be lower than that of the floating gates 119 .
[0024] An inter-gate insulating layer 127 is disposed along both sidewalls and the bottom surface of the recess region 125 , an upper surface of the upper insulating pattern 112 , and sidewalls and upper surfaces of the floating gates 119 . A word line 129 crosses over the active regions 109 and extends on the inter-gate insulating layer 127 . The word line 129 extends downward between the floating gates 119 . A protrusion portion 130 of the word line 129 is inserted into the recess region 125 of the upper insulating pattern 112 . A bottom surface of the protrusion portion 130 may be lower than that of the floating gate 119 . The word line 129 functions as a control electrode with respect to the floating gate 119 .
[0025] This protrusion portion 130 of the word line 129 operates to reduce a parasitic coupling capacitance between adjacent floating gate electrodes 119 by blocking direct capacitive coupling between opposing sidewalls of adjacent floating gate electrodes 119 .
[0026] Furthermore, increased lifetime of the non-volatile memory device can be achieved by providing portions of the insulating pattern 112 between the recess 125 and the active regions 109 . These portions of the insulating pattern 112 operate to block parasitic charge transfer from the active regions 109 to the inter-gate insulating layer 127 during repeated program and erase operations.
[0027] Referring now to FIG. 3 , a nonvolatile memory device according to an additional embodiment of the present invention is illustrated as being similar to the embodiment of FIG. 2 , however, the shape of the floating gate electrode 119 is modified to include a lower conductive pattern 119 _ 1 and an upper conductive pattern 119 _ 2 . As illustrated by FIG. 3 , a width of the lower conductive pattern 119 _ 1 is greater than a width of the active region 109 and greater than a width of the upper conductive pattern 119 _ 2 . To sustain high performance device characteristics, a width of the upper conductive pattern 119 _ 2 is in a range from about 0.5 times to about 0.7 times a width of the lower conductive pattern 119 _ 1 . By forming the upper conductive patterns 119 _ 2 to be narrower patterns, the parasitic gate-to-gate capacitance between adjacent floating gate electrodes 119 can be reduced without significantly reducing the inter-gate coupling between each floating gate electrode 119 and an overlapping word line/control gate 129 .
[0028] Referring now to FIG. 4 , a nonvolatile memory device according to an additional embodiment of the present invention is illustrated as similar to the embodiment of FIG. 3 , however, a lower conductive pattern 119 _ 1 is illustrated as having an equivalent width to the active region 109 . Moreover, the sidewalls of the active region 109 are self-aligned to the sidewalls of the lower conductive pattern 119 _ 1 . This self-alignment is achieved using the fabrication techniques illustrated by FIGS. 16-20 , which are described more fully hereinbelow.
[0029] Methods of forming the nonvolatile memory device of FIG. 2 will now be described more fully with reference to FIGS. 5-11 . In particular, FIG. 5 illustrates the steps of forming a pad oxide layer and a mask layer on a semiconductor substrate 101 and then photolithographically patterning these layers to define a pad oxide pattern 103 and a mask pattern 105 . The pad oxide layer may be formed as a thermal oxide layer, which operates to inhibit interface stress at a surface of the semiconductor substrate 101 . The mask layer may be formed as a polysilicon layer, an antireflective coating layer, a silicon nitride layer or a composite of these layers, for example. An etching step is then performed to define a plurality of isolation trenches 107 in the substrate 101 . These trenches 107 may be stripe-shaped trenches that extend in a third dimension (not shown). This etching step, which is preferably performed using the pad oxide pattern 103 and the mask pattern 105 as an etching mask, also results in the definition of a plurality of active regions 109 having expose sidewalls.
[0030] Referring now to FIG. 6 , lower and upper electrically insulating patterns 111 and 112 are then deposited, in sequence, in the trenches 107 . These lower insulating patterns 111 may be formed of a material having good gap-filling characteristics (i.e., low tendency to void formation) and the upper insulating patterns 112 may be formed of a material that is highly resistant to etching (e.g., wet etching). Such etching steps may include exposing the upper insulating patterns 112 to a wet etchant such as phosphoric acid or hydrofluoric acid. The lower insulating patterns 111 may be formed by filling the isolation trenches 107 with an undoped silicate glass (USG) layer and then recessing (e.g., etching back) the USG layer to thereby define the lower insulating patterns 112 . A high density plasma (HDP) oxide layer may then be deposited on the lower insulating patterns 111 and then planarized for a sufficient duration to expose upper surfaces of the mask pattern 105 , and thereby define the upper insulating patterns 112 .
[0031] Referring now to FIG. 7 , an etching process is performed to remove the mask pattern 105 and the pad oxide pattern 103 in sequence and thereby define a plurality of gap regions 115 that expose upper surfaces of the active regions 109 . As illustrated, this etching process may result in the lateral etching of the upper insulating patterns 112 , which means the gap regions 115 may have a larger width than the upper surfaces of the active regions 109 . Thereafter, as illustrated by FIG. 8 , a plurality of gate insulating layers 117 (e.g., tunnel oxide layers) and a plurality of floating gate electrodes 119 are formed in the gap regions 115 . These gate insulating layers 117 may be formed by performing a thermal oxidation process on the exposed upper surfaces of the active regions 109 . The floating gate electrodes 119 may be formed by depositing a polysilicon layer into the gap regions 115 and then planarizing the polysilicon layer to expose the upper insulating patterns 112 .
[0032] As illustrated by FIG. 9 , an etching step is then performed to etch-back the upper insulating patterns 112 so that upper sidewalls of the floating gate electrodes 119 are exposed. A molding insulating layer 121 is then conformally deposited on the upper surfaces and sidewalls of the floating gate electrodes 119 and on upper surfaces of recessed upper insulating patterns 112 . The molding insulating layer 121 may be formed of a material having an etching selectively with respect to the upper insulating patterns 112 . For example, the molding insulating layer 121 may be formed of a nitride layer or an oxide layer that is more susceptible to a wet etchant relative to the upper insulating patterns 112 .
[0033] Referring now to FIGS. 10-11 , the molding insulating layer 121 of FIG. 9 is anisotropically etched to define a plurality of molding spacers 122 that cover portions of the sidewalls of the floating gate electrodes 119 . The definition of these molding spacers 122 also results in the exposure of the upper insulating patterns 112 . These exposed portions of the upper insulating patterns 112 are then etched using the molding spacers 122 as an etching mask. This etching results in the formation of recesses 125 in upper portions of the upper insulating patterns 112 . As illustrated, these recesses 125 may have bottoms that are below the lower surfaces of the floating gate electrodes 119 . The molding spacers 122 are then removed (at least partially) using an etching process that exposes the sidewalls of the floating gate electrodes 119 . This etching process is preferably performed using an etchant (e.g., isotropic wet etchant) that does not significantly etch sidewalls of the recesses 125 in the upper portions of the upper insulating patterns 112 . For example, in the event the molding spacers 122 are formed of a nitride layer, the etching process can include an etchant containing phosphoric acid and the upper insulating patterns 112 can include a material that is relatively resistant to phosphoric acid. However, in the event the molding spacers 122 are formed of an oxide layer, the etching process can include an etchant containing hydrofluoric acid and the upper insulating patterns 112 can include a material that is relatively resistant to hydrofluoric acid.
[0034] Referring again to FIG. 2 , an inter-gate insulating layer 127 is then conformally deposited on the intermediate structure of FIG. 11 . As illustrated, this inter-gate insulating layer 127 is deposited on the floating gate electrodes 119 (upper surfaces and sidewalls) and the tipper insulating patterns 112 . This inter-gate insulating layer 127 also extends into the recesses 125 , as illustrated. The inter-gate insulating layer 127 may be formed as a composite of an oxide layer/nitride layer/oxide layer (i.e., ONO layer). A conductive layer is then deposited on the inter-gate insulating layer 127 and patterned to define a word line/control gate pattern 129 . This patterning of the word line/control gate pattern 129 may include patterning the floating gate pattern 119 into a plurality of floating gate electrodes 119 having dimensions that are self-aligned to the word line/control gate pattern 129 . As illustrated, the word line/control gate pattern 129 extends downward between the floating gates 119 . In particular, protruding portions 130 of the word line/control gate pattern 129 extend into the recesses 125 . The word line/control gate pattern 129 may be formed as a polysilicon layer, a metal layer and/or a silicide layer.
[0035] Alternatively, as illustrated by FIG. 12 , the exposed sidewalls of the floating gate patterns 119 of FIG. 11 may be etched-back using an isotropic wet etching process. This etching process results in the formation of a floating gate pattern 119 having a lower conductive pattern 119 _ 1 and an upper conductive pattern 119 _ 2 having different widths. This etching process may include using an etchant (e.g., wet etchant) that does not appreciably etch the upper insulating patterns 112 or the sidewalls of the recesses 125 . Thereafter, as illustrated by FIG. 3 , an inter-gate insulating layer 127 is conformally deposited on the intermediate structure of FIG. 12 . As illustrated, this inter-gate insulating layer 127 is deposited on the floating gate pattern 119 (upper surfaces and sidewalls) and the upper insulating patterns 112 . This inter-gate insulating layer 127 also extends into the recesses 125 , as illustrated. The inter-gate insulating layer 127 may be formed as a composite of an oxide layer/nitride layer/oxide layer (i.e., ONO layer). A conductive layer is then deposited on the inter-gate insulating layer 127 and patterned to define a word line/control gate pattern 129 . This patterning of the word line/control gate pattern 129 includes patterning the floating gate pattern 119 into a plurality of floating gate electrodes 119 having dimensions that are self-aligned to the word line/control gate pattern 129 . As illustrated, the word line/control gate pattern 129 extends downward between the floating gates 119 . In particular, protruding portions 130 of the word line/control gate pattern 129 extend into the recesses 125 . The word line/control gate pattern 129 may be formed as a polysilicon layer, a metal layer and/or silicide layer.
[0036] Referring now to FIGS. 8 and 13 - 15 , an alternative embodiment of a method of forming the device of FIG. 3 may include selectively etching back the upper insulating patterns 112 to expose sidewalls of the floating gate pattern 119 and then selectively etching the sidewalls of the floating gate pattern to define the lower conductive pattern 119 _ 1 and the narrower upper conductive pattern 119 _ 2 . Thereafter, as illustrated by FIGS. 14-15 , a molding insulating layer 121 is then conformally deposited on the upper surfaces and sidewalls of the upper conductive pattern 119 _ 2 and on upper surfaces of recessed upper insulating patterns 112 . The molding insulating layer 121 may be formed of a material having an etching selectively with respect to the upper insulating patterns 112 . For example, the molding insulating layer 121 may be formed of a nitride layer or an oxide layer that is more susceptible to a wet etchant relative to the upper insulating patterns 112 . Thereafter, as illustrated by FIG. 15 , the molding insulating layer 121 is anisotropically etched to define a plurality of molding spacers 122 that cover portions of the sidewalls of the floating gate electrodes 119 . The definition of these molding spacers 122 also results in the exposure of the upper insulating patterns 112 . These exposed portions of the upper insulating patterns 112 are then etched using the molding spacers 122 as an etching mask. This etching results in the formation of recesses 125 in upper portions of the upper insulating patterns 112 . As illustrated, these recesses 125 may have bottoms that are below the lower surfaces of the floating gate electrodes 119 . The molding spacers 122 are then removed (at least partially) using an etching process that exposes the sidewalls of the floating gate electrodes 119 . This removal of the molding spacers 122 results in the definition of the intermediate structure of FIG. 12 , which can be further processed as illustrated by FIG. 3 .
[0037] FIGS. 16-20 are cross-sectional views of intermediate strictures that illustrate methods of forming the non-volatile memory device of FIG. 4 . As illustrated by FIG. 16 , a gate insulating layer 117 and a floating gate pattern 119 are formed in sequence on a semiconductor substrate 101 . The floating gate pattern 119 is then used as etch mask to define a plurality of trenches 107 (e.g., stripe-shaped trenches) within the semiconductor substrate 101 . These trenches 107 define a plurality of semiconductor active regions therebetween, which extend opposite corresponding portions of the floating gate pattern 119 . By using the floating gate pattern 119 as an etching mask to define a plurality of trenches 107 , the active regions become self-aligned to the floating gate pattern 119 . Referring now to FIG. 17 , a lower insulating pattern 111 is formed within lower portions of the trenches 107 and an upper insulating pattern 112 is formed on the lower insulating pattern 111 , as illustrated. The lower insulating pattern 111 may be formed of a material having good gap-filling characteristics (i.e., low tendency to void formation) and the upper insulating pattern 112 may be formed of a material that is highly resistant to etching (e.g., wet etching), as previously described. An undoped silicate glass (USG) layer may be used for the lower insulating pattern 111 and a high-density plasma (HDP) oxide layer may be used for the floating gate pattern 119 .
[0038] Referring now to FIG. 18 , an etching process is performed on the intermediate structure of FIG. 17 in order to etch-back the upper insulating layer 112 and expose upper sidewalls of the floating gate pattern 119 . A molding insulating layer 121 is then conformally deposited on the exposed upper sidewalls and upper surfaces of the floating gate pattern 119 . The molding insulating layer 121 may be formed of a material having an etch selectivity with respect to the upper insulating pattern 112 . For example, the molding insulating layer 121 may be formed as a nitride layer or an oxide layer, depending on the material of the upper insulating pattern 112 .
[0039] An anisotropic etching step is then performed on the molding insulating layer 121 . This etching step is performed for a sufficient duration to thereby define molding spacers 122 on sidewalls of the floating gate pattern 119 , as illustrated by FIG. 19 . These molding spacers 122 are then used as an etching mask to selectively etch back exposed portions of the upper insulating pattern 112 . This selective etching of the upper insulating pattern 112 results in the formation of recesses 125 within the upper surfaces of the upper insulating pattern 112 , which are self-aligned to the molding spacers 122 . As illustrated, these recesses 125 may have bottoms that are lower than the underside surfaces of the floating gate pattern 119 , which interface with the gate insulating layer 117 .
[0040] Referring now to FIG. 20 , an etching process is performed on the intermediate structure of FIG. 19 to thereby remove the molding spacers 122 and expose sidewalls of the floating gate pattern 119 . This etching process (e.g., isotropic wet etching) is performed using an etchant that may selectively remove the molding spacers 122 and not substantially etch the upper insulating pattern 112 or widen the recesses 125 . For example, when the molding spacers 122 are formed of a nitride layer, the wet etching process can use an etchant containing phosphoric acid. Alternatively, when the molding spacers 122 are formed of an oxide layer, the wet etching process can use an etchant containing hydrofluoric acid.
[0041] Thereafter, as illustrated by FIG. 4 , an inter-gate insulating layer 127 is conformally deposited on the intermediate structure of FIG. 20 . This inter-gate insulating layer 127 is deposited on the floating gate pattern 119 (upper surfaces and sidewalls) and the upper insulating patterns 112 . This inter-gate insulating layer 127 also extends into the recesses 125 , as illustrated. The inter-gate insulating layer 127 may be formed as a composite of an oxide layer/nitride layer/oxide layer (i.e., ONO layer). A conductive layer is then deposited on the inter-gate insulating layer 127 and patterned to define a word line/control gate pattern 129 . This patterning of the word line/control gate pattern 129 includes patterning the floating gate pattern 119 into a plurality of floating gate electrodes 119 having dimensions that are self-aligned to the word line/control gate pattern 129 . As illustrated, the word line/control gate pattern 129 extends downward between the floating gates 119 . In particular, protruding portions 130 of the word line/control gate pattern 129 extend into the recesses 125 . The word line/control gate pattern 129 may be formed as a polysilicon layer, a metal layer and/or silicide layer.
[0042] In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.
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Non-volatile memory devices include a substrate with first and second semiconductor active regions therein. These active regions are separated from each other by a trench isolation region, which has a recess therein that extends along its length. First and second floating gate electrodes are provided. These first and second floating gate electrodes extend on the first and second semiconductor active regions, respectively. A control electrode is provided that extends between the first and second floating gate electrodes and into the recess in the trench isolation region. The recess in the trench isolation region is sufficiently deep so that the control electrode, which extends into the recess, operates to reduce (e.g., block) a parasitic coupling capacitance between the first and second floating gate electrodes.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. National Stage Application of International Application No. PCT/EP2007/057464 filed Jul. 19, 2007, which designates the United States of America, and claims priority to German Application No. 10 2006 033 866.9 filed Jul. 21, 2006, the contents of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] The invention relates to an arrangement comprising nanoparticles.
BACKGROUND
[0003] In this context, the term “nanoparticles” refers to particles which have a particle size of less than one micron—in at least one spatial dimension. As is known, nanoparticles can be used in various fields of technology. For example, the international publication WO 03/095111 A1 describes that nanoparticles can be arranged in array structures.
SUMMARY
[0004] According to various embodiments, an arrangement can be provided which has not only nanoparticle character but also further properties and thus qualifies for still further possible uses.
[0005] According to an embodiment, an arrangement may comprise a support and nanoparticles present thereon, wherein at least two nanoparticles which each comprise a metal material and differ in respect of the metal material are arranged at a distance from one another on a support surface of the support, and wherein the two metal materials are noble to a different extent.
[0006] According to a further embodiment, the distance between the two nanoparticles can be set so that the two nanoparticles form an electrochemical cell in an electrolyte. According to a further embodiment, the distance between the two nanoparticles may be from 5 μm to 10 μm. According to a further embodiment, the support may consist of an electrically nonconductive material or a material which has poor electrical conductivity. According to a further embodiment, the less noble metal material may be silver or comprises silver. According to a further embodiment, the more noble metal material may consist at least of one of palladium, platinum, rhodium and ruthenium or may comprise one of these metals. According to a further embodiment, a plurality of nanoparticles can be arranged in the manner of a chessboard so that each nanoparticle of one type is surrounded by four nanoparticles of the other type.
[0007] According to another embodiment, a process for producing an arrangement may comprise nanoparticles, wherein at least two nanoparticles which each comprise a metal material and differ in respect of the metal material are arranged at a distance from one another on a support surface of the support, and wherein the two metal materials are noble to a different extent.
[0008] According to a further embodiment, the distance between the two nanoparticles can be set so that the two nanoparticles form an electrochemical cell in an electrolyte. According to a further embodiment, the distance between the two nanoparticles may be from 5 μm to 10 μm. According to a further embodiment, an electrically nonconductive material or a material which has poor electrical conductivity may be selected for the support. According to a further embodiment, the less noble metal material can be silver or comprises silver. According to a further embodiment, the more noble metal material may consist of at least one of palladium, platinum, rhodium and ruthenium or may comprise one of these metals. According to a further embodiment, a plurality of nanoparticles which include at least two types of nanoparticles comprising metal materials which are noble to a different extent can be applied to the support surface. According to a further embodiment, each nanoparticle may have at least one nanoparticle of the other type arranged directly adjacent to it. According to a further embodiment, the distance between each nanoparticle of the one type and the directly adjacent nanoparticle of the other type can be in the range from 5 μm to 10 μm. According to a further embodiment, a first perforated mask having a predetermined first arrangement of holes can be applied to the support surface of the support, nanoparticles of a first metal material can be affixed to the support surface in the positions determined by the arrangement of holes, a second perforated mask having a predetermined second arrangement of holes can be applied to the support surface, and nanoparticles of a second metal material can be affixed to the support surface in the positions determined by the arrangement of holes in the second perforated mask. According to a further embodiment, the nanoparticles of the first metal material can be formed in the holes of the first perforated mask by the first metal material being deposited on the support surface in the region of the holes, and/or the nanoparticles of the second metal material may be formed in the holes of the second perforated mask by the second metal material being deposited on the support surface in the region of the holes. According to a further embodiment, finished nanoparticles of the first metal material can be introduced into the holes of the first perforated mask and affixed to the support surface and/or finished nanoparticles of the second metal material can be introduced into the holes of the second perforated mask and affixed to the support surface. According to a further embodiment, an auxiliary layer which provides chemical coupling positions for each of the two types of nanoparticles, to which the nanoparticles can couple chemically, can be applied to the support surface, with the coupling positions being located at a distance from one another, and a mixture of finished nanoparticles of at least two metal materials which are noble to a different extent can be applied to the support surface provided with the auxiliary layer and a nanoparticle distribution determined by the arrangement of the coupling positions on the auxiliary layer is achieved on the support. According to a further embodiment, the auxiliary layer may be formed by applying a polymer layer having a molecular structure which provides at least one coupling position for each of the two types of nanoparticles to the support surface. According to a further embodiment, the auxiliary layer can be formed by applying a crosslinking material comprising self-assembling molecules which each provide at least one coupling position to the support surface. According to a further embodiment, the plurality of nanoparticles can be arranged in the manner of a chessboard so that each nanoparticle of one type is surrounded by four nanoparticles of the other type. According to a further embodiment, a mixture of finished nanoparticles of at least two metal materials which are noble to a different extent can be applied to a support provided with a perforated mask.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention is illustrated below with the aid of various examples; here, by way of example,
[0010] FIGS. 1-6 show a first example of a process according to an embodiment for producing an example of an arrangement or structure according to an embodiment, in which two perforated masks are used,
[0011] FIGS. 7-11 show a second example of a process according to an embodiment for producing an example of an arrangement or structure according to an embodiment, in which only one perforated mask is used,
[0012] FIG. 12 shows a third example of a process according to an embodiment for producing an example of an arrangement or structure according to an embodiment, in which an auxiliary layer is used, and
[0013] FIG. 13 shows a fourth example of a process according to an embodiment for producing an example of an arrangement or structure according to an embodiment, in which a type of auxiliary layer different from that in FIG. 12 is used.
[0014] In FIGS. 1 to 13 , identical reference signs are used in the interests of clarity for identical or comparable components.
DETAILED DESCRIPTION
[0015] The various embodiments accordingly provide for at least two nanoparticles which each comprise a metal material and are different in respect of the metal material to be arranged at a distance from one another on a support surface of a support, where the two metal materials are noble to a different extent or have different redox potentials.
[0016] A significant advantage of the arrangement according to various embodiments is that the nanoparticles can, as a result of the different nobility or the different redox potentials of the metal materials, have further chemical properties: for example, they can form an electrochemical cell as soon as they are brought into contact with an electrolyte. The ability to form an electrochemical cell enables the arrangement to be utilized, for example, in various technical fields, for example in the medical sector. For example, the arrangement can display an antibacterial action when its interaction with an electrolyte results in flow of electric current between the nanoparticles. Apart from use in the medical sector, the arrangement is also, owing to its electrochemical properties, suitable for other applications, for example for the internal coating of condenser tubes, heat exchangers or the like. A lotus flower effect or catalytic effects can also be displayed by the arrangement when suitable materials are selected.
[0017] As already mentioned, the distance between the two nanoparticles is preferably set so that the two nanoparticles can form an electrochemical cell in an electrolyte. A distance between the two nanoparticles of from 5 μm to 10 μm is considered to be preferred.
[0018] With regard to simple production of the arrangement, it is considered to be advantageous for the support surface to be planar or flat, at least on sections; in this case, the nanoparticles can lie in the same plane, at least approximately spatially in the same plane.
[0019] The two metallic materials are preferably formed by pure materials such as chemical elements or metal alloys.
[0020] To avoid an electric short circuit between the nanoparticles, it is considered to be advantageous for the support to consist of an electrically nonconductive material or a material which has poor electrical conductivity.
[0021] If the arrangement is used in the human or animal body for the purposes of medical procedures, it is considered to be advantageous for the release of metal ions to be minimized since liberated metal ions in the human or animal body can, if the concentration is too high, sometimes cause damage. A release of ions can be reduced, or at least significantly slowed, when the difference between the redox potentials of the materials of the two nanoparticles is very small. The two metallic materials are preferably selected so that the difference between the redox potentials is less than 200 mV. The difference between the redox potentials corresponds to the thermodynamic driving force for the release of ions. The release of ions is, however, also determined by the kinetic properties of the surface, which influence the chemical behavior of the nanoparticles.
[0022] For use of the arrangement as antibacterial “active compound” in the human or animal body, it is considered to be advantageous for the less noble metallic material of the two nanoparticles to be formed by silver since silver has an antibacterial action, in particular when together with chloride ions of an electrolyte it forms a silver chloride layer on the particle comprising silver.
[0023] To avoid release of silver ions into the human body, the other metallic material should preferably not be much more noble than silver. A suitable partner material for silver is, for example, palladium which has a redox potential of 0.92 V. Since silver has a redox potential of 0.8 V, the difference between the two redox potentials is about 120 mV and therefore relatively low, so that release of silver ions from the silver particle occurs very slowly and/or is prevented for at least some period of time when a silver chloride layer can be formed on the silver particle.
[0024] With a view to a very compact construction of the arrangement, it is considered to be advantageous for a plurality of nanoparticles to be arranged in the manner of a chessboard, for example on a flat or planar support surface, in such a way that each nanoparticle of one type is surrounded by four nanoparticles of the other type. In the case of such a positioning of the nanoparticles, a very low density of electrochemical cells per unit area of the support surface can be achieved.
[0025] Further embodiments provide a process for producing an arrangement comprising nanoparticles.
[0026] In this respect, it is provided according to various embodiments that at least two nanoparticles which each comprise a metal material and differ in respect of the metal material are applied at a distance from one another to a support surface of a support, where the two metal materials are noble to a different extent.
[0027] As regards the advantages of the process resulting from the different nobility of the two metal materials, reference may be made to what has been said above in connection with the arrangement according to various embodiments.
[0028] As already mentioned, the distance between the two nanoparticles is preferably set so that the two nanoparticles can form an electrochemical cell in an electrolyte. For example, the distance between the two nanoparticles is in the range from 5 μm to 10 μm.
[0029] To avoid a situation where the support prevents formation of electrochemical cells between the nanoparticles or makes this difficult, it is considered to be advantageous for an electrically nonconductive material or a material which has poor electrical conductivity to be used as support material.
[0030] As already mentioned, preference is given to using silver or a silver-containing material as the less noble metal material. As the more noble metal material, preference is given to using palladium, platinum, rhodium and/or ruthenium or a material which contains this metal or a plurality of these metals.
[0031] Particular preference is given to applying a plurality of nanoparticles, namely at least two types of nanoparticles which comprise metal materials which are noble to a different extent, to the support surface. Each nanoparticle preferably has at least one nanoparticle of the other type arranged directly adjacent to it.
[0032] As regards the formation of electrochemical cells, it is considered to be advantageous for the distance between each nanoparticle of the one type and the directly adjacent nanoparticle of the other type to be from 5 μm to 10 μm.
[0033] In a particularly preferred variant, it is considered to be advantageous for a first perforated mask having a predetermined first arrangement of holes to be applied to the support surface of the support, for nanoparticles of a first metal material to be affixed to the support surface in the positions determined by the arrangement of holes, for a second perforated mask having a predetermined second arrangement of holes to be applied to the support surface and for nanoparticles of a second metal material to be affixed to the support surface in the positions determined by the second perforated mask.
[0034] For example, the nanoparticles of the first metal material are formed in the holes of the first perforated mask by the first metal material being deposited on the support surface, in particular grown onto the support surface, in the region of the holes, and/or the nanoparticles of the second metal material are formed in the holes of the second perforated mask by the second metal material being deposited on the support surface, in particular grown onto the support surface, in the region of the holes. Growing on can be effected, for example, electrochemically in an electrochemical bath.
[0035] As an alternative, finished nanoparticles of the first metal material can be introduced into the holes of the first perforated mask and affixed to the support surface, and/or finished nanoparticles of the second metal material can be introduced into the holes of the second perforated mask and affixed to the support surface.
[0036] In another preferred variant, it is considered to be advantageous for an auxiliary layer which provides chemical coupling positions for each of the at least two types of nanoparticles, to which the nanoparticles can be chemically coupled, to be applied to the support surface, with the coupling positions being located at a distance from one another, for a mixture of finished nanoparticles of at least two metal materials which are noble to a different extent to be applied to the support surface provided with the auxiliary layer and for a nanoparticle distribution predetermined by the arrangement of the coupling positions on the auxiliary layer to be achieved on the support.
[0037] For example, the auxiliary layer is formed by applying a polymer layer having a molecular structure which provides at least one coupling position for each of the two types of nanoparticles to the support surface.
[0038] As an alternative, the auxiliary layer can be formed by applying a crosslinking material having self-assembling molecules which each provide at least one coupling position to the support surface.
[0039] With a view to a maximum density of electrochemical cells per unit area, it is considered to be advantageous for the plurality of nanoparticles to be arranged in the manner of a chessboard so that each nanoparticle of one type is surrounded by four nanoparticles of the other type.
[0040] In another preferred variant, it is considered to be advantageous for a mixture of finished nanoparticles of at least two metal materials which are noble to a different extent to be applied to a support provided with a perforated mask, and for a nanoparticle distribution which is predetermined by the stoichiometry, or is random or stochastic to be achieved on the support.
[0041] In conjunction with FIGS. 1 to 6 , a first example of a process for producing an arrangement comprising nanoparticles will now be described.
[0042] In FIG. 1 , it is possible to see a support 10 on which a first photomask 20 has been applied. The photomask 20 is structured and has holes 30 ; the photomask 20 thus forms a perforated mask. The structuring of the photomask 20 can be carried out in a customary way, for example by electron beam structuring, laser structuring or another optical structuring method.
[0043] Nanoparticles 40 are then grown onto the support 10 which has been coated in this way, by applying a first metal material M 1 to the support 10 . The growing-on of the nanoparticles 40 can be effected in any way, for example in a vapor deposition step (e.g. CVD step) or a sputtering step. In addition, the deposition of the metal material M 1 can be aided magnetically or electrostatically. Deposition of the metal material M 1 by an electrochemical route, for example in an electroplating bath in the form of an “electroforming” step, is also possible.
[0044] The structure provided with the nanoparticles 40 is shown in FIG. 2 ; the first photomask 20 is still present.
[0045] After deposition of the nanoparticles 40 , the first photomask 20 is removed completely and a second photomask 50 is subsequently applied. The second photomask 50 is likewise structured so that holes 60 are formed. During the application of the second photomask or perforated mask 50 , the nanoparticles 40 which have been deposited in the preceding step are embedded in the second photomask 50 ; this is shown schematically in FIG. 3 .
[0046] In a second deposition step, nanoparticles 70 of a second metal material M 2 are then deposited; these nanoparticles 70 therefore form a different type of nanoparticles. The growing-on of the second metal material M 2 is carried out in a manner comparable to the growing-on of the first metal material M 1 , i.e., for example, as has been described in relation to FIG. 2 . The resulting structure is shown in FIG. 4 .
[0047] After detachment of the second perforated mask 50 , there remains a finished arrangement 90 in which nanoparticles 40 of a first metal material M 1 and nanoparticles 70 of a second metal material M 2 have been applied to the support 10 . The distance between nanoparticles of different metal materials is denoted by the reference sign A in FIG. 5 . The spacing A is preferably from about 5 to 10 μm.
[0048] The two materials M 1 and M 2 are selected so that the redox potentials of the two materials M 1 and M 2 are different. In the following, it is assumed by way of example that the first material M 1 of the nanoparticles 40 is a metal which is less noble, or a metal alloy which is less noble, than the second material M 2 of the nanoparticles 70 .
[0049] The property of a metal of being noble or not noble is indicated by the respective redox potential or the electrochemical potential series; the following list, which is illustrative and not intended to be conclusive, of metals suitable for nanoparticles is ordered from not noble to noble or in order of increasing redox potentials (redox potential versus standard hydrogen electrode at 25° C.):
[0000]
lithium
−3 V
magnesium
−2.4 V
aluminum
−1.7 V
zinc
−0.8 V
silver
+0.8 V
palladium
+0.9 V
[0050] A material which is very suitable, in particular with a view to medical applications, is, for example, silver since silver or silver ions has/have an antibacterial action. Accordingly, it is assumed below by way of example that silver is used as first not noble material M 1 since the less noble material can release ions in an electrolyte in an electrochemical cell.
[0051] The second material M 2 of the nanoparticles 70 is accordingly a more noble metal, for example gold or palladium. Palladium has a redox potential of 0.92 V, which is relatively similar to that of silver so that the difference D between the redox potentials of the two materials M 1 (silver) and M 2 (palladium) is only D=120 mV.
[0052] If the structure 90 as shown in FIG. 5 is brought into contact with an electrolyte by, for example, introducing it into the human body, the silver material M 1 will react with chloride ions, which are always present in body fluids or cell fluids of the human body, of the electrolyte so that a highly chemically stable silver chloride layer will form on the nanoparticles 40 . This silver chloride layer will separate the surface of the nanoparticles 40 from the electrolyte, so that direct release of silver ions from the nanoparticles 40 into the electrolyte is prevented or at least greatly slowed. The formation of the silver chloride layer on the surface of the nanoparticles 40 thus ensures that no unacceptably high release of silver ions into the human body can occur. Nevertheless, an antibacterial effect is achieved since the silver chloride layer itself acts as a bactericide.
[0053] Instead of the silver/palladium materials combination described, it is also possible to use other materials combinations, in particular ones based on silver, in order to display an antibacterial action: other suitable materials combinations are, for example, silver-platinum, silver-ruthenium and silver-rhodium.
[0054] In the selection of the materials, it should preferably be ensured that, when silver is used, the not noble material of the two materials M 1 and M 2 is formed by the silver so that it can generate ions and/or form the silver chloride layer described. In addition, the difference between the redox potentials should not be too great. Potential differences which are too great increase the reactivity of the electrochemical cell, so that excessively rapid release of silver ions which may be too high for human or animal bodies could occur. The potential difference is preferably less than 500 mV.
[0055] FIG. 6 shows the resulting structure 90 from above. It can be seen that the nanoparticles 40 and the nanoparticles 70 are arranged in the manner of a chessboard so that each nanoparticle of one type is surrounded by four adjacent partner nanoparticles of the other type.
[0056] In conjunction with FIGS. 7 to 11 , a second example of the production of an arrangement comprising nanoparticles will now be described.
[0057] In FIG. 7 , it is possible to see a support 10 to which a perforated mask 100 has been applied. The perforated mask 100 can again be formed by an appropriately structured photomask.
[0058] A mixture of finished nanoparticles 110 is then applied to the support 10 provided with the perforated mask 100 . The mixture 110 comprises nanoparticles 40 of a first metal material M 1 and nanoparticles 70 of a second metal material M 2 . The mixture has such a composition that the number of nanoparticles of the first metal material M 1 corresponds approximately to the proportion of nanoparticles of the second metal material M 2 .
[0059] The mixture 110 is then applied to the support 10 provided with the perforated mask 100 so that the openings or holes 120 of the perforated mask 100 are filled with the nanoparticles 40 or 70 . The distribution of the nanoparticles 40 or 70 in the openings 120 is random and depends essentially on the composition of the mixture 110 . The resulting structure after application of the mixture 110 is shown schematically in FIG. 9 .
[0060] FIG. 10 shows the arrangement comprising the support 10 and the nanoparticles 40 and 70 after the perforated mask 100 has been removed. To affix the nanoparticles 40 or 70 to the support surface 130 of the support 10 , the nanoparticles can be affixed by means of an additional fixing material. Such a fixing material is not shown further in FIG. 10 for reasons of clarity.
[0061] FIG. 11 shows, in plan view, the distribution of the nanoparticles 40 and 70 on the support surface 130 of the support 10 . It can be seen that, in contrast to the first example shown in FIGS. 1 to 6 , the nanoparticles are not distributed in the manner of a chessboard but are distributed randomly. The distribution of the nanoparticles on the support surface 130 is determined by the random distribution or composition of the mixture 110 of the nanoparticles 40 and 70 .
[0062] In conjunction with FIG. 12 , a third example of a process for producing an arrangement comprising a support and nanoparticles will now be described. A support 10 to which an auxiliary layer 200 has been applied can be seen in FIG. 12 . The auxiliary layer 200 is, for example, a polymer layer which comprises chain-like molecules 210 . The chain-like molecules 210 are aligned along or parallel to the support surface 130 of the support 10 . As can be seen in FIG. 12 , the chain-like molecules 210 are provided with a plurality of coupling positions 220 and 230 to which nanoparticles can couple.
[0063] In the example shown in FIG. 12 , it is assumed by way of example that the coupling positions 220 are suitable or designed for coupling to silver nanoparticles 240 and that the coupling positions 230 are suitable or designed for coupling to palladium nanoparticles 250 . The corresponding coupling possibilities are shown schematically in FIG. 12 by the shape of the coupling positions 220 and 230 or by the shape of the corresponding countercoupling positions of the palladium nanoparticles 250 and the silver nanoparticles 240 .
[0064] In the third example as shown in FIG. 12 , it is assumed that the auxiliary layer 200 is specifically suitable for coupling of palladium nanoparticles 250 and silver nanoparticles 240 ; of course, it can be ensured by means of an appropriate configuration of the molecular structure of the chain-like molecules 210 that other types of nanoparticles can be attached in a corresponding way.
[0065] A suitable material for the auxiliary layer 200 is, for example, cetyltrialkylammonium bromide.
[0066] After the support 10 has been provided with the auxiliary layer 200 described, a mixture of finished nanoparticles 240 and 250 is applied to the auxiliary layer 200 . Owing to the coupling points 220 and 230 provided by the auxiliary layer 200 , the nanoparticles 240 and 250 are correspondingly coupled to the auxiliary layer 200 , so that they become attached in a predetermined manner to the support 10 . The arrangement 90 comprising the support 10 and the nanoparticles 240 and 250 is then finished.
[0067] In conjunction with FIG. 13 , a fourth example of a process for producing an arrangement 90 comprising a support 10 and nanoparticles will now be described. In this example, an auxiliary layer 400 formed by a crosslinking base material 410 with self-assembling molecules 420 present therein is applied to the support surface 130 of the support 10 . The auxiliary layer 400 thus itself forms a self-assembling layer.
[0068] The self-assembling molecules 420 are configured so that they couple by a molecule end 430 to the support surface 130 of the support 10 . By means of another molecule end 440 , they form a coupling position to which the nanoparticles having an appropriate countercoupling position can couple. The left-hand molecule 420 ′ in FIG. 13 forms, for example, a coupling position 220 for the silver nanoparticles 240 and the middle molecule 420 ″ in FIG. 13 forms, for example, a coupling position 230 for the palladium nanoparticles 250 .
[0069] The molecules 420 also have functional groups f which fix the distance A between the molecules 420 . The distance A between the molecules 420 thus at the same time defines the spacing A which the nanoparticles 240 and 250 will have on the support 10 .
[0070] After coupling of the nanoparticles 240 or 250 to the molecules 420 and thus to the support 10 , the base material 410 can be removed so that only the molecules 420 and the nanoparticles 240 and 250 are now present on the support 10 .
[0071] A suitable material for the auxiliary layer 400 is, for example, material having oligomeric chains comprising polythiophene derivatives.
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An arrangement ( 90 ) has a support ( 10 ) and nanoparticles ( 40, 70 ) that are located thereupon. At least two nanoparticles ( 40, 70 ), both of which are made of a metal material (M 1 , M 2 ) and are different regarding the metal material, are disposed at a distance from one another on a surface ( 130 ) of the support ( 10 ). The two metal materials have a different degree of preciousness.
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BACKGROUND OF THE INVENTION
This invention relates generally to the joining of metals, and, more particularly, to diffusion bonding of non-ferrous metals at elevated temperatures and pressures.
In many applications of metals, a metal piece must be joined to another metal piece to create a useful structure. It has long been a common practice to join metal pieces with conventional fasteners such as bolts, rivets, or screws, or with specialized fasteners. Metal pieces are also joined by welding or brazing, using a filler metal between the joined pieces.
These conventional techniques are usually successful in joining the pieces, but may not produce the strongest and most durable joint possible because of stress concentrations, irregularities, and incomplete bonding at the interface between the pieces joined. The stress concentrations, irregularities and incomplete bonds often act as the points of initiation of cracks and thence failure during service, so that the joint becomes the primary source of weakness in the structure.
As a solution to the joining problem for structures that are to be used at room temperature or low elevated temperatures, specialized organic adhesives such as epoxies have been developed. The pieces to be joined are essentially glued together by the adhesive. The adhesive spreads the loads transmitted through the joint across the entire area of the joint, reducing the incidence of failure due to stress concentrations. However, the strength of such adhesives falls rapidly with increasing temperature, so that pieces to be used at temperatures greater than about 250° C. cannot be joined with such adhesives.
Some metals may be joined together by cleaning a smooth surface on each and subsequently pressing them together under pressure, in a nonreactive environment and at elevated temperature. This process is known as diffusion bonding. The material in the two pieces interdiffuse slightly, and the grains of the two pieces grow across the interface, so that in reality the interface disappears. When two pieces of the same or similar composition and microstructure are diffusion bonded together properly, it is often impossible to discern where the interface was, even with high power microscopes. Moreover, the joint becomes as strong and durable as the underlying pieces being bonded, and is not a favored site for failure initiation. This diffusion bonding process is therefore highly preferred where it can be used to advantage.
Not all metals can be readily diffusion bonded For example, a tough oxide scale at the surface, as found on aluminum alloys, prevents interdiffusion. The oxide can sometimes be broken by mechanical working and/or chemical cleaning, but a remnant typically remains in the interfacial region as a source of defects
In some cases, nature has provided metals having a desirable combination of properties useful in particular applications, coupled with the ability to be diffusion bonded. One commercially more important of such metals is titanium and its alloys. Titanium dissolves its own oxide at elevated temperatures, removing this impediment to the diffusion bonding process.
A sufficient pressing pressure must be applied for a period of time in order to provide enough plastic flow or deformation to remove irregularities and voids at the interface, and force the two pieces into full contact along the entire interface. The titanium alloys are often selected because of their high strength at elevated service temperatures, but this high strength acts to slow the diffusion bonding operation at a selected temperature by reducing the rate of plastic flow necessary to achieve full bonding. The rate of flow can be increased by increasing the bonding pressure, but this approach reduces the size of pieces that can be bonded by use of a mechanical bonding press of a particular force capacity Alternatively, if the bonding pressure if provided by isostatic pressing, more complex and expensive equipment is required to achieve higher pressures.
Normally, effective diffusion bonding temperatures for titanium alloys are relatively high, to increase the rate of diffusion so that voids can be eliminated and bonding achieved without excessive pressure or excessive bonding time. For conventional alpha-beta titanium alloys such as Ti-6Al-4V, diffusion bonding temperatures are usually selected which range from about the beta transus temperature (about 995° C.) to well below the beta transus temperature (about 870° C.)
These high bonding temperatures are often undesirable, since they can cause phase coarsening and poor mechanical properties in the finished article. High bonding temperatures are also undesirable when reinforcing particles or fibers must be included within a diffusion bonded article as in fabrication of metal-matrix composites. In this case, high bonding temperatures can cause reaction between the included particles or fibers and the matrix metal, severely reducing the strength of the finished composite article Lowering of diffusion bonding temperatures is an important goal in further improving diffusion bonding operations,
There have been several approaches to enhancing diffusion bonding :f titanium alloys. In one, the alloy composition is changed to reduce elevated temperature flow strength. Bonding is thereby enhanced, but the ultimate usefulness of the bonded structure is reduced In another approach, bonding is accelerated by coating the surfaces to be bonded with a fugitive coating that accelerates bonding, but then diffuses away into the bulk of the metal during the bonding operation. This method introduces undesired impurities into the final structure, particularly near to the bond line.
In still another approach described in U.S. Pat. No. 3,713,207, a specially prepared thin, fine-grained, superplastic foil interlayer is placed between the pieces to be bonded. The superplastic properties of the foil reduce bonding pressures and/or temperatures However, preparation of the foil material is often difficult or prohibitively expensive, making this approach undesirable for many diffusion bonding needs.
Accordingly, there exists a continuing need for an improved technique for bonding pieces of titanium and other types of alloys that can inherently be diffusion bonded. Such a technique should provide for reduced bonding temperatures and/or pressures, and should not adversely affect the performance of the final bonded structure, as by leaving an incompletely bonded joint, residue, or impurities. The present invention fulfills this need, and further provides related advantages.
SUMMARY OF THE INVENTION
The present invention resides in a process for bonding together two pieces of metal, at least one of which is preferably a titanium alloy. Operable titanium alloys include the conventional structural titanium alloys such as the alpha-beta alloy Ti-6Al-4V, and also advanced intermetallic alloys such as titanium aluminides of the form Ti 3 Al, all of which have an operable phase transformation at elevated temperatures. The process permits accelerated bonding, without introducing alloying elements or contaminants that remain in the vicinity of the joint to interfere with the strength and durability of the joint in service The process can be implemented in any of several ways, depending upon the availability of furnaces and presses.
In accordance with the invention, a process for bonding together two pieces of metal comprises the steps of furnishing the two pieces of metal to be bonded at least a first piece of which is selected from the group consisting of titanium and an alloy of titanium having a phase whose stability is modified by the presence of hydrogen, introducing hydrogen into at least the first piece of metal to reduce its flow stress at an elevated bonding temperature, and pressing the two pieces together under an applied bonding pressure and at the elevated bonding temperature.
Upon solidifying from the melt, pure titanium exhibits a body-centered-cubic crystal structure, termed the beta phase. As the titanium is cooled to a temperature below about 880° C., the beta phase transforms to a hexagonalclose-packed crystal structure, termed the alpha phase, which is stable down to room temperature. Many titanium alloys also exhibit such a beta to alpha transformation, and the metallurgy of most of the commercial titanium alloys is related to the selection of particular chemical compositions and processing to achieve desirable physical properties. The temperature above which the alpha phase cannot exist is termed the beta transus, and the exact value of the beta transus is dependent upon the alloying elements present in the titanium alloy For example, the beta transus of the commercially important titanium alloy Ti-6Al-4V is about 995° C.
A titanium-based alloy may be entire alpha phase when cooled below the beta transus temperature entirely beta phase, or a mixture of alpha and beta phases. The beta phase can exist below the beta transus temperature because certain alloying elements stabilize the beta phase, and due to the slow reaction kinetics of the beta to alpha transformation.
In the diffusion bonding operation, two pieces of metal are cleaned and are placed together in a face to face relation. Pressure is applied perpendicular to the interfacial plane, and any surface irregularities are flattened out under the influence of the pressure. As the irregularities are flattened, the degree of interfacial contact increases, with a consequent decrease in the amount of open space or porosity at the interfacial joint. Continued pressure results in removal of the porosity and voids at the interface by a combination of plastic flow and diffusion until the interface is sound and without porosity, Atoms diffuse across the interface during this treatment, effectively removing traces of the interface if the bonding is accomplished properly.
Thus, to achieve good diffusion bonding, there should be both a low resistance to plastic flow in the pieces being bonded, to eliminate surface irregularities, and a high rate of diffusion to eliminate porosity at the interface during the terminal stages of bonding. It might be expected that these objectives could be best attained by accomplishing diffusion bonding at as high a temperature as possible, just below the melting point of the alloy. However, diffusion bonding of titanium alloys is normally accomplished at a temperature below the beta transus temperature, and often just below that temperature. Many titanium alloys exhibit superplastic flow at temperatures below the beta transus. In superplastic flow, large strains can be achieved with low applied stresses, permitting the removal of a major part of the surface irregularities and residual porosity by plastic flow rather than by the slower diffusional processes. Also, if the titanium alloy is heated above the beta transus, the structure becomes entirely beta phase. The flow stress of the beta phase is less than that of the alpha phase material, increasing the rate of bonding. Unfortunately, the beta phase alloy is susceptible to rapid coarsening of the grains in the microstructure, with the result that the final piece that has been bonded above the beta transus exhibits poor properties at lower temperatures.
The introduction of hydrogen into the metal alloy as a solute lowers the temperature of the beta transus, because hydrogen is a beta stabilizer. The result of lowering the beta transus temperature is to increase the amount of beta phase present at any selected temperature. The increased amount of beta phase present can be used directly to accelerate diffusion bonding, since beta phase has a lower flow stress and higher self-diffusion rate than alpha phase, at diffusion bonding temperatures.
In this direct approach, hydrogen is introduced under pressure to the pieces being diffusion bonded, during the diffusion bonding operation. A portion of the alpha phase present transforms to the beta phase due to the introduction of the beta phase stabilizer hydrogen. Because the beta phase has a lower flow stress than the alpha phase at a selected temperature, a fixed applied diffusion bonding pressure results in an accelerated rate of plastic flow at the diffusion bonding interface and more rapid bonding. The diffusion dependent portion of the diffusion bonding operation is also accelerated, as the beta phase has a greater self diffusion (or bulk diffusion) rate than the alpha phase. The effect of the introduction of hydrogen into the pieces during diffusion bonding is to lower the required diffusion bonding temperature to achieve a desired bonding rate. The temperature reduction is significant, inasmuch as the phases would otherwise tend to coarsen during higher temperature diffusion bonding treatments, an undesirable result that impairs the mechanical properties of the completed structure. The structure bonded by the present approach has a finer finished microstructure than achieved by normal diffusion bonding.
The hydrogen can also be charged into the metallic piece prior to the initiation of diffusion bonding, in a precharging step. In this approach, the piece to be elevated temperature. A pressure of hydrogen is applied, so that the hydrogen diffuses into the piece to the extent possible. The piece is cooled, with the pressure of hydrogen continuously applied. For some alloys, it is necessary to limit the amount of hydrogen introduced into the piece to be bonded to avoid excessive formation of hydrides which could lead to cracking of the piece. The piece charged with hydrogen is then transferred to a diffusion bonding furnace, assembled with the other pieces to be bonded, and diffusion bonded under an applied pressure and at the diffusion bonding temperature. Care must be taken to prevent the hydrogen from diffusing out of the solid pieces during the diffusion bonding operation This may be accomplished by applying a partial pressure of hydrogen to the pieces being bonded, or by providing a diffusion barrier coating to the pieces.
The introduction and removal of hydrogen can be accomplished prior to commencing diffusion bonding, to achieve a reduced alpha grain size in the piece to be subsequently diffusion bonded. The reduced alpha grain size results in an increased rate of superplastic flow at a selected pressing pressure during the diffusion bonding operation. The increased rate of flow accelerates the plastic flow-dependent portion of the diffusion bonding operation. The finer grain size also leads to an increased rate of grain boundary-dependent mass diffusion, accelerating the diffusion-dependent portion of the diffusion bonding operation.
The increased amount of beta phase induced by the presence of hydrogen can also be used indirectly to accelerate diffusion bonding. In the indirect method, hydrogen is alternately diffused into the metal piece and removed from the metal piece while the metal piece is held at an elevated temperature less than that of the beta transus when no hydrogen is present, with the result that the structure of the metal piece alternates between a lesser amount of beta phase (when no or a low level of hydrogen is present) and a greater amount of beta phase (when a substantial amount of hydrogen is present).
The introduction and removal of hydrogen is accomplished concurrently with the application of a diffusion bonding pressure, at the diffusion bonding temperature. In this case, the introduction and removal of hydrogen is accomplished cyclically, with hydrogen introduced and then removed while diffusion bonding pressure is applied. The hydrogen introduction and removal is repeated at least several times while the diffusion bonding proceeds. The hydrogen introduced in this manner also lowers the beta transus temperature, which leads to an increase in the fraction of beta phase present (when the hydrogen level is high) and an increase in the fraction of alpha phase present (when the hydrogen level is low). Under the influence of the applied pressure, the grains are deformed even as they are formed, leading to a more efficient deformation process that accelerates the flow-dependent portion of the diffusion bonding operation. This phenomenon is a form of transformation induced plasticity. The diffusion dependent portion of the diffusion bonding operation is also accelerated, due to the increased amount of grain boundary area at various stages of the hydrogen cycling.
Hydrogen is a particularly useful solute to be used to alter the structure of the alloys in the diffusion bonding operation. The hydrogen is a strong beta phase stabilizer, so that its introduction and removal at constant temperature, can significantly alter the microstructure by changing the relative amounts of beta and alpha phase at a temperature below the normal, hydrogen-free beta transus, Hydrogen diffuses rapidly at elevated temperature through titanium and other metals wherein the solubility of hydrogen in the metal is relatively high. The hydrogen may therefore be introduced rapidly by placing the metal piece into a pressure chamber and applying a pressure of hydrogen. The hydrogen is also removed rapidly by removing the hydrogen pressure and allowing the hydrogen to diffuse out of the metal piece, or applying a vacuum to accelerate hydrogen removal.
It is important to be certain that the hydrogen has been removed substantially completely at the end of the diffusion bonding operation, as hydrogen can embrittle the diffusion bonded piece at lower temperatures, or even diffuse to adjacent pieces and embrittle them. Fortunately, the introduction and removal of hydrogen at elevated temperatures is essentially reversible, if accomplished properly. The final removal step must be accomplished above the temperature of formation of hydrides, which are solid, hydrogen-containing compounds of titanium or the alloying elements that are formed when a hydrogen-charged piece is cooled below the formation temperature of the particular hydride. The hydrides themselves may be harmful to mechanical properties, and also can serve as the source of a later introduction of mobile hydrogen to the metallic lattice upon reheating the bonded structure.
The introduction of hydrogen can also be considered from the standpoint of when the hydrogen is introduced. Thus, a process for bonding together two pieces of metal comprises the steps of furnishing the two pieces of metal to be bonded, at least a first piece of which is selected from the group consisting of titanium or an alloy of titanium, introducing hydrogen into at least the first piece of metal to reduce its flow stress at an elevated bonding temperature, and pressing the two pieces together under an applied bonding pressure and at the elevated bonding temperature, the step of introducing hydrogen to be completed prior to beginning the step of pressing.
In another approach, a process for bonding together two pieces of metal comprises the steps of furnishing the two pieces of metal to be bonded, at least a first piece of which is selected from the group consisting of titanium or an alloy of titanium, introducing hydrogen into at least the first piece of metal to reduce its flow stress at an elevated bonding temperature, and pressing the two pieces together under an applied bonding pressure and at the elevated bonding the temperature, the step of introducing hydrogen to be accomplished concurrently with the step of pressing.
Hydrogen can be introduced either under a constantly applied pressure to charge the pieces, or in an alternating fashion to enhance transformation induced plasticity. The flow stress of the piece is reduced through the increase in the fraction of beta phase present, when the hydrogen pressure is constantly applied, or through the alternating transformations between the alpha and beta phases, under the alternating application of hydrogen pressure.
The approach of the present invention does not preclude post-bonding procedures. For example, after bonding, the structure can be heat treated by conventional procedures to achieve particular strength or durability levels. The structure can be machined or otherwise mechanically processed. Once the hydrogen is substantially fully removed from the bonded parts, it may be treated or processed. However, the microstructure of the bonded parts, in the as-bonded condition, is superior to that of conventional diffusion bonded structure, in that the microstructure is finer.
At least one of the pieces to be diffusion bonded must be susceptible of this treatment, for the present approach of hydrogen-assisted diffusion bonding to be operable. Preferably, both pieces to be bonded at an interface can be treated by this approach for optimal results. However, even if only one of the pieces is susceptible, an improvement in the diffusion bonding is achieved.
The diffusion bonding process of the invention is operable with titanium alloys having a beta transus. It is also operable with other alloys, such as zirconium alloys, having a similar elevated temperature phase transformation that is strongly affected by the introduction of the hydrogen solute.
Although other solutes can have the same effect as hydrogen in modifying the beta transus, it is presently believed that hydrogen must be used as the solute to achieve the beneficial results of the invention. Other solutes cannot diffuse with the rapidity of hydrogen, or be reversibly introduced and removed.
It should now be appreciated that the diffusion bonding process of the present invention presents a significant advance in the art of bonding together alloys having an elevated temperature phase transformation sensitive to the presence of a hydrogen solute. The present approach permits accelerated bonding of titanium and related alloys, without deleterious effects on the final bonded structure. Indeed, the final microstructure is typically enhanced after the hydrogen-assisted diffusion bonding operation, as compared with that produced by conventional diffusion bonding. Other features and advantages of the present invention will be apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic side sectional view of a diffusion bonding apparatus: and
FIG. 2 is a diagrammatic side sectional view of a hydrogen treatment furnace.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is embodied in a process for diffusion bonding pieces of metal, and the pieces so bonded. By way of background and so that the context of use of the invention may be understood, FIGS. 1 and 2 illustrate the apparatus used in conjunction with the process of the invention. FIG. 1 illustrates a diffusion bonding apparatus 10 for diffusion bonding together a first piece of metal 12 and a second piece of metal 14. The apparatus 10 includes a chamber 16 that may, for the practice of some embodiments, be pressurized and/or evacuated. The pieces 12 and 14 are contained within the chamber 16 and are heated by any appropriate method In the illustrated apparatus 10 the heating is accomplished by placing the chamber 16, and the pieces 12 and 14 contained therein, into a controllable furnace 18.
Within the chamber 16, the pieces 12 and 14 are supported by a movable platen 20, which is supported on a piston 22 that extends through seals 24 in the wall of the chamber 16, to the exterior of the chamber 16. The piston 22 is moved by force application unit 26, which is typically either a mechanical motor or a hydraulic ram, to apply a compressive force to the pieces 12 and 14. The compressive force transmitted to the pieces 12 and 14 through the platen 20 is reacted against a stationary platen 28. The combination of the furnace 18 and the force application unit 26 thus permit a compressive force to be applied to an interface 30 between the pieces 12 and 14, at a selected elevated temperature. One of the limits of any such diffusion bonding apparatus 10 is the force (as in pounds) that is available from the force application unit 26. For any particular such unit 26, the less compressive pressure (as in pounds per square inch of interface 30) required to complete the diffusion bonding operation, the greater is the size of the pieces 12 and 14 that may be bonded, where the size of the pieces 12 and 14 is measured in terms of the area of the interface 30. It is therefore desirable to minimize the compressive pressures required for bonding, to reduce the size of the costly unit 26. Similarly, the shorter the time required to complete the bonding operation, the more throughput that may be achieved in the apparatus 10. Thus, metallurgical techniques to decrease the compressive pressure required and shorten the bonding time can reduce the capital costs of the apparatus 10. In addition, techniques which result in lower bonding temperatures are beneficial in providing refined microstructures in the finished articles.
In some of the embodiments to be described, a continuous or cyclically alternating gaseous hydrogen pressure is applied to the pieces 12 and 14, concurrently with the heating and application of compressive force. To provide the hydrogen, a hydrogen line 32 communicates with the interior of the chamber 16. Hydrogen pressure is regulated by a hydrogen valve 34 in the line 32, which regulates the flow of hydrogen from a gas supply 36. The gas supply 36 will include at least a partial pressure of hydrogen gas, but may also include an inert gas to reduce the possibility of an explosive detonation of hydrogen in the event of a gas leak. Hydrogen pressure can be reduced or removed from the interior of the chamber 16 through a relief valve 38. A vacuum may optionally be drawn on the interior of the chamber 16 by a vacuum pump 40, if it is desired to withdraw all traces of hydrogen from the interior of the chamber 16. By manipulating the valves 34 and 38 and selectively operating the pump 40, the hydrogen pressure within the chamber 16 can be maintained steady, increased, decreased, or reduced to zero, as required
In others of the embodiments to be described, hydrogen is charged into one or both of the pieces 12 and 14 prior to their being loaded into the apparatus 10. This pre-bonding charging is accomplished in a charging apparatus 42, illustrated in FIG. 2. The apparatus 42 includes a charging chamber 44 into which a piece of metal 46 is placed. To provide the hydrogen, a hydrogen line 48 communicates with the interior of the chamber 44. Hydrogen pressure is regulated by a hydrogen valve 50 in the line 48, which regulates the flow of hydrogen from a gas supply 52. The gas supply 52 will include at least a partial pressure of hydrogen gas, but may also include an inert gas to reduce the possibility of an explosive detonation of hydrogen in the event of a gas leak. Hydrogen pressure can be reduced or removed from the interior of the chamber 44 through a relief valve 54. A vacuum may optionally be drawn on the interior of the chamber 16 by a vacuum pump 56, if it is desired to withdraw all traces of hydrogen from the interior of the chamber 44. By manipulating the valves 50 and 54 and selectively operating the pump 56, the hydrogen pressure within the chamber 44 can be maintained steady, increased, decreased, or reduced to zero, as required.
The pieces of metal 46 contained within the chamber 44 can be heated by any operable means. In the preferred embodiment, the entire chamber 44, as well as the pieces of metal 46, are placed into a furnace 58. With this approach, the pieces of metal 46 can be given programmed hydrogen charging treatments prior to their diffusion bonding in the apparatus 10. The diffusion bonding apparatus 10 could be used for the charging treatments, but in most instances the apparatus 10 is sufficiently costly that it would not be used to accomplish charging treatments that can be performed in the less costly charging apparatus 42. In addition to the bonding method of apparatus 10, hot isostatic pressing or any other suitable means of diffusion bonding may be used to bond articles pre-charged with hydrogen in apparatus 42.
Several embodiments of the invention are presently known, with the first embodiment described below being the most preferred at the present time.
In the first embodiment, the titanium (as used herein, "titanium" includes pure titanium and alloys of titanium and other elements) pieces to be bonded are placed into the charging apparatus 42 and subjected to a cycle of pressurizing and depressurizing the chamber 44 with hydrogen gas. Such cyclic treatments are known to alter the microstructure, as disclosed in U.S. Pat. No. 4,505,764, whose disclosure is herein incorporated by reference. Hydrogen gas diffuses into the pieces to charge them with hydrogen during the pressurizing part of the cycle, and diffuses out of the pieces to reduce their hydrogen content during the depressurizing portion of the cycle. The cycle of pressurizing and depressurizing is conducted with the pieces at a constant temperature slightly below the beta transus temperature, but above the temperature at which hydrides form. During this cyclic treatment, the beta phase is stabilized when the chamber is pressurized, increasing the fraction of beta phase present in the pieces. Conversely, the relative fraction of alpha phase is increased when the hydrogen is removed. The cyclic change in the fractions of the phases present has the effect of refining the alpha grain size after the cyclic treatment is complete, and the pieces are returned to ambient temperature. At the completion of the cyclic treatment, the residual hydrogen gas may be removed by the pump 56 prior to cooling below the temperature at which hydrides form.
After the completion of the cyclic treatment in the apparatus 42, the pieces to be bonded are placed into the apparatus 10, at the locations indicated by the pieces 12 and 14. The temperature of the pieces is increased to the diffusion bonding temperature, and a pressure applied perpendicular to the interface 30 by the platens 20 and 28. After a time sufficient to achieve complete diffusion bonding, the pressure is removed, the temperature reduced to ambient, and the bonded pieces removed. Alternatively, the pre-treated pieces may be consolidated by hot isostatic pressing.
In a second embodiment, a procedure similar to that of the first embodiment is followed, except that the gas pressure applied when the pieces are within the apparatus 42 is not cyclic, but is generally steady and constant. The hydrogen pressure stabilizes the beta phase and increases its fraction of the total material. The pieces are then cooled to ambient temperature, so that solid solution hydrogen is present within the pieces. The hydrogen-loaded pieces are transferred to the apparatus 10 and diffusion bonded. Upon re-heating the pieces 12 and 14 within the apparatus 10, the hydrogen solute stabilizes the beta phase, and increases its relative fraction during the bonding operation. The beta phase flows more easily than does the alpha during the bonding operation, resulting in more rapid deformation consolidation at the interface.
In a third embodiment, the pieces 12 and 14 to be bonded are loaded directly into the bonding apparatus 10. The pieces are heated to the diffusion bonding temperature and a bonding pressure applied through the platens 20 and 28. The bonding temperature is below the beta transus temperature but above the temperature at which hydrides form. While the diffusion bonding pressure is applied through the platens 20 and 28, the chamber 16 is alternatively pressurized and depressurized multiple times with hydrogen. After bonding is complete, hydrogen is removed from the articles by applying a vacuum to the apparatus 10.
The introduction of hydrogen causes hydrogen to diffuse into the pieces 12 and 14, stabilizing the beta phase. Depressurization of the chamber by removing the hydrogen reduces the fraction of beta phase and increases the fraction of alpha phase. The cyclic change of the relative volume fractions of the phases, under the influence of the cyclic hydrogen pressure variation, assists plastic deformation in a manner similar to that of a transformation induced plasticity. The plastic flow component of the diffusion bonding is thereby accelerated. The diffusional component is also accelerated, due to the increased selfdiffusion coefficient rate of the beta phase. Upon completion of the bonding operation, the remaining hydrogen is removed from the pieces by evacuating the diffusion bonding chamber.
The fourth embodiment is similar to the third embodiment, in that the entire treatment is accomplished within the apparatus 10, and the charging apparatus 42 is not used. In the fourth embodiment, instead of cyclically pressurizing and depressurizing the chamber 16 with hydrogen, a relatively constant hydrogen pressure is introduced into the chamber concurrently with the application of pressure perpendicular to the interface 30 through the platens 20 and 28, and the heating to the diffusion bonding temperature. Hydrogen diffuses into the pieces 12 and 14 under the driving force of the hydrogen pressure in the chamber 16. The hydrogen in the pieces 12 and 14 stabilizes the beta phase, increasing its volume fraction at the diffusion bonding temperature. The diffusion bonding temperature is selected to be a temperature below the unpressurized beta transus temperature, but above the pressure at which hydrides form.
Using this approach, the rate of bonding is increased above that experienced for bonding at that temperature and applied platen pressure, but without applied hydrogen gas pressure, because the increased fraction of beta phase deforms more easily than does the corresponding amount of alpha phase, and because the beta phase has a greater self-diffusion rate than does the alpha phase at the same temperature. Both the deformation and diffusion components of diffusion bonding are thereby accelerated. Upon completion of the bonding operation, the hydrogen is removed by the application of a vacuum and the bonded pieces are cooled to room temperature.
Thus, the approach of the present invention provides an important new process for diffusion bonding titanium alloys and similar materials which are susceptible to the hydrogen induced transformation. The introduction of hydrogen, normally thought to be detrimental to parts because of the danger of hydrogen embrittlement, is reversible in the sense that the hydrogen can be removed by an elevated temperature vacuum treatment after bonding is complete. Although particular embodiments of the invention have been described for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
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A piece of a titanium-base alloy having an elevated temperature phase transformation is diffusion bonded to a second phase at an accelerated rate or reduced temperature, as compared with conventional diffusion bonding, by manipulating the phase transformation with an alloying element that can be readily introduced into, and removed from, the titanium piece. The introduction of hydrogen into the titanium alloy reduces the temperature of the phase transformation. The titanium alloy can be repeatedly cycled through the phase transformation before or during bonding, by the introduction and removal of hydrogen, to reduce the flow stress through transformation plasticity. Alternatively, the titanium alloy may be loaded with hydrogen to reduce the phase transformation temperature, increasing the fraction of the more deformable phase and then reducing the flow stress of the alloy at the diffusion bonding temperature.
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BACKGROUND OF THE INVENTION
[0001] The following describes a new invention in the field of capacitive touch screens or 2-dimensional capacitive transducing (2DCT) sensors. U.S. Pat. No. 6,452,514, U.S. Pat. No. 7,148,704 and U.S. Pat. No. 5,730,165 disclose a capacitive measurement technique which makes it possible to create touch responsive transparent or opaque sensing regions that can detect human touch through several millimeters of plastic or glass. Described herein is a new structure for a touch screen that allows significant enhancement in both operation and appearance of the sensor.
[0002] U.S. Pat. No. 6,452,514 describes a capacitive measurement technique which is incorporated by reference herein, that uses a transmit-receive process to induce charge across the gap between an emitting electrode and a collecting electrode (the transmitter and the receiver respectively, also referred to as X and Y). The capacitive sensing described in U.S. Pat. No. 6,452,514 may be referred to as mutual capacitive or active type 2DCT sensors. As a finger touch interacts with the resulting electric field between the transmitter and receiver electrodes, the amount of charge coupled from transmitter to receiver is changed. A particular feature of the measurement technique is that most of the electric charge tends to concentrate near to sharp corners and edges (a well known effect in electrostatics). The fringing fields between transmitter and receiver electrodes dominate the charge coupling. The electrode design therefore tends to focus on the edges and the gaps between neighboring transmitter and receiver electrodes in order to maximize coupling and also to maximize the ability of a touch to interrupt the electric field between the two, hence giving the biggest relative change in measured charge. Large changes are desirable as they equate to higher resolution and equally to better signal to noise ratio.
[0003] A specially designed control chip can detect these changes in charge. It is convenient to think of these changes in charge as changes in measured coupling capacitance between transmitter and receiver electrodes (charge is rather harder to visualize). The chip processes the relative amounts of capacitive change from various places around the touch screen and uses this to compute the absolute location of touch as a set of x and y coordinates. In order for this to be possible a set of spatially distributed electrodes must be used. Commonly, these electrodes are required to be transparent so that the touch screen can operate in front of a display such as a liquid crystal display (LCD) screen or other display screen type, for example organic light emitting diode (OLED) type screens. To achieve this electrodes are often fabricated from a material known as Indium Tin Oxide (ITO) but other transparent conductive materials are also suitable. ITO has desirable properties in optical terms, but can be substantially ohmic which can have a negative impact on capacitive measurements if the resistance and capacitance combination leads to time constants that prevent timely settling of the charge transfer process.
[0004] Another example 2DCT is disclosed in US20070062739A1
[0005] In order to create a sensor that can report the absolute coordinates of the location of the touch (or more than one touch) on the surface of the sensor or the overlying plastic or glass panel, the electrode arrangement must be specifically designed to optimize the following aspects:
accuracy of the reported touch location i.e. correspondence between real physical location and reported location. This is broadly known as “linearity” or “non-linearity” when referring to the measured error. immunity of the sensor to external electrical noise sources. sensitivity of the sensor to human touch i.e. its ability to detect a touch through thicker panel materials, or to detect a lighter or smaller touch. spatial resolution of the sensor i.e. its ability to report small changes in touch location. quality of the output in terms of the noise or jitter amplitude in the reported location. optical quality of the sensor for the transmission of light, for factors like its transparency, its hue, its haze, the overall electrode pattern visibility etc. optical behavior of the sensor to shallow angle reflected light i.e. the visibility of the electrode pattern and any color shifts in the reflected light. minimizing any errors induced in the reported location caused by slight mechanical flexing during human touch. This tends to cause a change in the distance between the sensor and any underlying display or other mechanical grounded structure which in turn causes capacitive changes similar to a touch. reducing the electrical resistance of the electrodes to allow efficient capacitive sensing within an acceptable time (often the overall measurement time of the touch screen needs to be at or below 10 ms so limiting the amount of settling time that can be used to make each measurement). reducing the number of layers in the physical construction to minimize manufacturing cost and to improve optical properties. reducing side-effects in the quality of reported coordinates or in the ability of the sensor to detect a touch, near to the edges of the sensor. This region typically presents difficult challenges in this regard because of the non-uniformity of the electrode pattern (its ends) and the fact that interconnecting tracks tend to reside at the edges of the sensor. reducing the total number of electrodes used as each electrode requires some connection to the control chip and so more electrodes equates to a more complex chip and hence higher cost.
[0018] In order to optimize linearity, the electrode pattern design is critical. Linearity is one of the primary measures of quality of a touch screen because as the linearity degrades, it becomes harder to report an accurate touch location in some regions of the screen. A sensor design that offers excellent intrinsic linearity is a key goal therefore. While it is possible to mathematically correct such non-linearity via well known techniques such as a look-up table or piecewise-linear correction, any of these methods actually trades off spatial resolution for reported linearity, and so is always a compromise.
[0019] In designing the electrodes a key objective is to arrange that the electric field that propagates from transmitter to receiver does so in a way that causes a smooth and progressive gradation from one electrode to the next. This way, as a touch moves from region to region, the capacitive change measured by the control chip also changes in a smooth and progressive way and hence contributes to good intrinsic linearity. The touch itself actually influences this process significantly and will tend to “mix” the fields from neighboring electrodes. This contributes to the overall smoothness of transition, but does tend to lead to some variation in linearity depending on the size of the touch applied. Again, electrode design needs to be carefully considered to optimize the linearity across a range of touch sizes.
[0020] As described above the quality of the output in terms of the noise or jitter amplitude in the reported location should be optimized. However, 2DCT sensors can be sensitive to external ground loading. Furthermore, electrical noise generated from LCD screens can interfere with capacitance measurements when a pointing object approaches the screen. Known methods to minimize the effects of noise on capacitive coupling is to increase the separation or air gap between an LCD screen and an overlaying 2DCT sensor. Alternatively a shielding layer may be incorporated between the LCD screen and a 2DCT sensor to reduce or block the noise induced by the LCD screen.
[0021] WO 2009/027629 published on 5 Mar. 2009 describes a capacitive touch sensor comprising a dielectric panel overlying a drive electrode with two sense electrodes. One of the sense electrodes is positioned to be shielded from the drive electrode by the first sense electrode, so that the first sense electrode receives the majority of the charge coupled from the drive electrode and the second sense electrode primarily registers noise. A sensing circuit including two detector channels is connected to the first (coupled) and second (noise) sense electrodes to receive signal samples respectively. The sensing circuit is operable to output a final signal obtained by subtracting the second signal sample from the first signal sample to cancel noise.
[0022] However, the methods described above increase the size and thickness, and may decrease the resolution of a device incorporating a display screen with a 2DCT sensor when it is more fashionable and desirable to produce smaller devices. Furthermore, additional steps are required during manufacture and as a result there is an increased cost due to further components being needed.
[0023] European patent EP 1821175 describes an alternative solution to reduce the noise collected on a 2DCT touch sensor. EP 1821175 discloses a display device with a touch sensor which is arranged so that the two dimensional touch sensor is overlaid upon a display device to form a touch sensitive display screen. The display device uses an LCD arrangement with vertical and horizontal switching of the LCD pixels. The touch sensing circuit includes a current detection circuit, a noise elimination circuit as well as a sampling circuit for each of a plurality of sensors, which are arranged to form the two-dimensional sensor array. The current detection circuit receives a strobe signal, which is generated from the horizontal and vertical switching signals of the LCD screen. The strobe signal is used to trigger a blanking of the current detection circuit during a period in which the horizontal switching voltage signal may affect the measurements performed by the detection circuit.
[0024] WO 2009/016382 published on 5 Feb. 2009 describes a sensor used to form a two dimensional touch sensor, which can be overlaid on a liquid crystal display (LCD) screen. As such, the effects of switching noise on the detection of an object caused by a common voltage signal of the LCD screen can be reduced. The sensor comprises a capacitance measurement circuit operable to measure the capacitance of the sensing element and a controller circuit to control charging cycles of the capacitance measurement circuit. The controller circuit is configured to produce charging cycles at a predetermined time and in a synchronous manner with a noise signal. For example, the charge-transfer cycles or ‘bursts’ may be performed during certain stages of the noise output signal from the display screen, i.e. at stages where noise does not significantly affect the capacitance measurements performed. Thus, the sensor can be arranged to effectively pick up the noise output from a display screen and automatically synchronize the charge-transfer bursts to occur during stages of the noise output cycle.
[0025] However, noise reduction techniques such as those described above require more complex measurement circuitry. This makes the measurement circuitry more expensive and may increase the time taken to complete an acquisition cycle.
[0026] It would therefore be desirable to provide an electrode pattern suitable for mutual capacitive or active type 2DCT sensor that can be embodied with an electrode pattern with reduced noise pick-up.
SUMMARY OF THE INVENTION
[0027] According to a first aspect of the invention, a capacitive touch sensor is provided comprising a touch sensitive panel having a plurality of drive electrodes arranged on one side of a substrate in a first layer and a plurality of sense electrodes arranged on the other side of the substrate in a second layer so that the sense electrodes cross the drive electrodes at a plurality of intersections offset from each other by the thickness of the substrate, wherein the drive electrodes substantially entirely cover the first layer with individual ones of the drive electrodes being separated from neighboring drive electrodes by small gaps.
[0028] This approach has several important advantages. The touch sensor only requires the two layers of electrodes recited above to function, so that a third noise-suppressing layer as adopted in some prior art designs is superfluous. A two layer construction also leads to improved optical transmission, thinner overall depth and lower cost compared with designs with a greater numbers of layers. The area-filling design for the drive electrodes with small gaps allows for an almost invisible drive electrode pattern, for example when using ITO, and also isolates the sense lines from capacitive effects below the first layer, for example noise from an underlying LCD module or other noise source. The “flooding” of the first layer with conductive material also allows the second layer to be implemented with narrow sense electrodes, far narrower than the dimension of the sensing object. The second layer can also be made invisible either through in-filling of islands of electrode material between the sense electrodes to also “flood” the second layer, or alternatively simply by making the sense electrodes very thin or very sparse with line widths so small that they are invisible. This sparse approach using meshes is described further below. The reduced sense electrode area also reduces susceptibility to coupling noise from touches.
[0029] The drive electrodes are preferably separated by a pitch of comparable dimension to the touch size of the touching object for which the sensor is designed.
[0030] The touching object for which the sensor is designed may be a finger, e.g. of touch size 8-10 mm diameter, and the pitch is around 8 mm or less. A stylus could also be used.
[0031] The small gaps between adjacent drive electrodes are preferably dimensioned to be sufficiently small to be invisible or almost invisible, for example less than around 100 micrometers, preferably having dimensions of a few tens of micrometers.
[0032] The sense electrodes are advantageously narrow in comparison to the size of the touching object. For example, the sense electrodes may have a line width of one quarter or less of the size of the touching object. In one embodiment, the touching object for which the sensor is designed is a finger with a touch size of 8-10 mm diameter, and the sense electrodes have a line width of 2 mm or less, for example 0.5 mm. The sense electrodes may have a line width one quarter or less than the pitch of the drive electrodes.
[0033] In some embodiments, the second layer additionally accommodates isolated elements arranged between the sensing electrodes so that the sense electrodes and the isolated elements together substantially entirely cover the second layer with individual ones of the sense electrodes and isolated elements being separated from each other by small gaps. The small gaps have comparable function and dimensions to the small gaps between the drive electrodes.
[0034] As mentioned above, the first and second layers of electrodes may be the only electrode layers provided, a two-layer electrode construction leading to improved optical transmission for transparent embodiments such as used for touch-sensitive displays, thinner overall construction, and lower cost.
[0035] The drive electrodes preferably cover the first layer sufficiently entirely that the sense electrodes in the second layer are substantially isolated from capacitive effects below the first layer.
[0036] An important combination is the above-defined capacitive touch sensor with a display module. The display module, for example an LCD or OLED display panel, will typically by arranged below the first layer and distal the touch surface so that from top to bottom, or outside to inside the device, the components will be—dielectric layer the upper surface of which will be the touch surface—layer 2 —substrate—layer 1 —display panel, with the display panel being inside the device housing or outer shell. In a display application, the electrodes will likely be made of ITO.
[0037] In some embodiments, each drive and/or sense electrode is made of a continuous sheet of electrically conductive material, such as ITO or a metal. In other embodiments, each drive and/or sense electrode is made of a mesh or filigree pattern of interconnected lines of highly conductive material which collectively define each electrode. Still further embodiments use continuous sheets for one of the electrode types and meshes for the other electrode type. In the mesh approach, the interconnected lines preferably have a sufficiently small width so as to be invisible or almost invisible. They can then be made of material that is not inherently invisible, e.g. a metal such as copper, but still remain practically invisible.
[0038] The invention can be implemented to form a Cartesian xy grid of touch sensor locations. In particular, the drive electrodes can extend in a first linear direction and the sense electrodes in a second linear direction transverse to the first linear direction so that the plurality of intersections form a grid pattern, for example a square, diamond or rectangular grid. The invention can also be implemented to form a polar ‘rθ’ grid, wherein the drive electrodes extend arcuately and the sense electrodes extend radially so that the plurality of intersections lie on one or more arcuate paths.
[0039] A further aspect of the invention relates to a touch sensitive panel for a capacitive touch sensor, the touch sensitive panel having a plurality of drive electrodes arranged in a first layer and a plurality of sense electrodes arranged in a second layer so that the sense electrodes cross the drive electrodes at a plurality of intersections offset from each other, wherein the drive electrodes substantially entirely cover the first layer with individual ones of the drive electrodes being separated from neighboring drive electrodes by small gaps. The first and second layers can be disposed on opposite sides of a common substrate offset from each other by the thickness of the substrate. Alternatively, the first and second layers can be disposed on different substrates which can then be assembled in engagement with each other to provide an offset between the two layers equal to the thickness of one of the substrates, or both of them, depending on which side of the substrates the electrodes are arranged.
[0040] The touch sensitive panel has a plurality of drive electrodes arranged on one side of a substrate in a first layer and a plurality of sense electrodes arranged on the other side of the substrate in a second layer so that the sense electrodes cross the drive electrodes at a plurality of intersections offset from each other by the thickness of the substrate, wherein the drive electrodes substantially entirely cover the first layer with individual ones of the drive electrodes being separated from neighboring drive electrodes by small gaps.
[0041] A still further aspect of the invention relates to a method of manufacturing a touch sensitive panel for a capacitive touch sensor comprising:
[0042] providing a substrate having first and second sides;
[0043] depositing on the first side of the substrate a first layer of conductive material in a first pattern forming a plurality of drive electrodes, wherein the drive electrodes substantially entirely cover the first layer with individual ones of the drive electrodes being separated from neighboring drive electrodes by small gaps; and
[0044] depositing on the second side of the substrate a second layer of conductive material in a second pattern forming a plurality of sense electrodes so that the sense electrodes cross the drive electrodes at a plurality of intersections offset from each other by the thickness of the substrate.
[0045] The invention may also be defined by a touch sensitive panel having an electrode pattern comprising a plurality of drive electrodes extending in a first direction and spaced apart in a second direction; wherein the drive electrodes are spaced apart by a distance of less than 100 μm and have a pitch of less than or equal to 8 mm.
[0046] The drive electrodes may be spaced apart by a distance 90, 80, 70, 60, 50, 40, 30, 20 or 10 μm. The pitch of the drive electrodes may be less than or equal to 5 mm.
[0047] The same extent of each drive electrode may be coupled to adjacent drive electrodes using a resistor. The typical resistor values used range from a few KΩ to 10's of KΩ. The resistors may be discrete resistors, screen printed resistive elements or meandering patterns formed using the same material as the drive electrodes.
[0048] The width of the drive electrodes at the outer edges of the electrode pattern may be half the width of the other drive electrodes.
[0049] The electrode pattern may further comprise a plurality of sense electrodes extending in a second direction and spaced apart in the first direction crossing the drive electrodes.
[0050] The sense electrodes may be spaced apart by a plurality of isolated electrodes wherein having the same extent in the first and second direction as the width of the sense electrodes. The space or gaps between the isolated electrodes is of the order of 10's of μm.
[0051] The width of the sense electrodes may be substantially less than the width of the drive electrodes. The width of the sense electrode is typically in the range of 100 to 1000 μm
[0052] According to another aspect of the present invention there is provided a two-dimensional position sensor comprising the electrode pattern of drive electrodes and sense electrodes, wherein the drive electrodes and the sense electrodes may be disposed on opposing surfaces of a substrate.
[0053] According to another aspect of the present invention there is provided a two-dimensional position sensor comprising the electrode pattern of drive electrodes and sense electrodes, wherein the drive electrodes and the sense electrodes may be disposed on a surface of two different substrates.
[0054] The two-dimensional position sensor may further comprise a controller comprising a drive unit for applying drive signals to the drive electrodes, and a sense unit for measuring sense signals received from each of the respective sense electrode representing a degree of capacitive coupling of the drive signals between the drive electrodes and each of the sense electrodes.
[0055] The controller may further comprise a processing unit for calculating a position of an interaction with the sensitive area from an analysis of the sense signals obtained by applying drive signals to the drive electrodes.
[0056] The processing unit may be operable to determine position in the first direction by an interpolation between sense signals obtained from each of the plurality of sense electrodes.
[0057] The processing unit may be operable to determine position in the second direction by an interpolation between sense signals obtained by sequentially driving each of the plurality of drive electrodes with respective drive signals.
[0058] According to another aspect of the present invention there is provided a two-dimensional position sensor comprising the electrode pattern of drive electrodes, further comprising a plurality of sense electrodes extending in a second direction and spaced apart in the first direction crossing the drive electrodes; wherein the drive electrodes and the sense electrodes are disposed on opposing surfaces of a substrate; the two-dimensional sensor further comprising a controller comprising: a drive unit for applying drive signals to the drive electrodes; wherein the drive electrodes are grouped together into a subset of drive electrodes such that the drive unit is operable to apply drive signals to the outer-most drive electrodes of each subset of drive electrodes; and a sense unit for measuring sense signals received from each of the respective sense electrode representing a degree of capacitive coupling of the drive signals between the drive electrodes and each of the sense electrodes.
[0059] According to another aspect of the present invention there is provided a method of sensing position of an actuation on a two-dimensional position sensor comprising: an electrode pattern comprising a plurality of drive electrodes extending in a first direction and spaced apart in a second direction; wherein the drive electrodes are spaced apart by a distance of less than 100 μm and have a pitch of less than or equal to 8 mm; a plurality of sense electrodes extending in a second direction and spaced apart in the first direction crossing the drive electrodes; wherein the drive electrodes and the sense electrodes are disposed on opposing surfaces of a substrate; the method comprising: applying drive signals to the drive electrodes, measuring sense signals received from each of the respective sense electrodes representing a degree of capacitive coupling of the drive signals between the drive electrodes and each of the sense electrodes; determining position in the first direction by an interpolation between sense signals obtained from each of the plurality of sense electrodes; and determining position in the second direction by an interpolation between sense signals obtained by sequentially driving each of the plurality of drive electrodes with respective drive signals.
[0060] The invention may alternatively be defined by a two-dimensional touch screen comprising: a substrate; a plurality of driven-electrodes extending in a first direction on a first surface of the substrate; a plurality of Y-electrodes extending in a second direction being perpendicular to the first direction on a second surface of the substrate opposing the first surface of the substrate; wherein the plurality of driven-electrodes substantially fill an area of the first surface of the substrate, for example.
[0061] Two-dimensional touch screens are typically used as on overlay on a display screen. The area filling design of the driven electrodes leads to an almost invisible electrode pattern. The area filling design also provides partial attenuation of noise coupled from an underlying LCD module or other noise source.
[0062] The two-dimensional touch screen may further comprise a subset of driven-electrodes comprising two outer most driven-electrodes and two or more intermediate driven-electrodes connected together using a plurality of resistive elements. This reduces the interconnecting wiring between the touch screen and the control chip.
[0063] The width of the two outer most driven electrodes may be half the width of the other driven-electrodes to improve the overall linearity of the measured capacitance.
[0064] The width of the Y-electrodes may be substantially less than the width of the driven-electrodes such that the Y-electrodes are not easily visible to the human eye and narrower electrodes provide better noise immunity.
[0065] The spacing between each of the plurality of driven-electrodes may be less then 100 μm to make the pattern substantially invisible to the human eye.
[0066] The pitch of the drive-electrodes and the Y-electrodes may be 8 mm or less to achieve a good intrinsic linearity and to match the size of a typical finger touch.
[0067] The area between each of said Y-electrodes may be filled with isolated conductive material such that is it possible to make narrow Y-electrodes while still have a pattern that is substantially invisible to the human eye and can reduce the susceptibility to coupling noise from a touch.
[0068] The Y-electrodes of the two-dimensional touch screen may further comprise a plurality of equally disposed cross-members running in the first direction. This can achieve uniform field patterns that are symmetrical in all regions of the touch screen leading to good linearity. These cross members effectively act to spread the electric field further beyond the primary Y-electrode to overlap the region which can gradate the electric field.
[0069] According to the another aspect of the invention there is provided a method of determining a touch location adjacent a two-dimensional touch screen comprising: a substrate; a plurality of driven-electrodes extending in a first direction on a first surface of the substrate; a plurality of Y-electrodes extending in a second direction being perpendicular to the first direction on a second surface of the substrate opposing the first surface of the substrate; wherein the plurality of driven-electrodes substantially fill an area of the first surface of the substrate; the method comprising the steps of: applying a potential to each of the plurality of driven-electrodes while the other driven-electrodes are held at a zero potential; measuring the capacitance at each intersection formed between the driven electrodes and the Y electrodes; generating measurements at each intersection formed between the driven electrodes and the Y electrodes; and computing the touch location based on the generated measurements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0070] For a better understanding of the invention, and to show how the same may be carried into effect, reference is now made by way of example to the accompanying drawings, in which:
[0071] FIG. 1A shows a side view of a two-electrode layer capacitive touch screen according to an embodiment of the present invention;
[0072] FIG. 1B shows a perspective view of a two-electrode layer capacitive touch screen according to an embodiment of the present invention;
[0073] FIG. 1C shows a side view of a two-electrode layer capacitive touch screen according to another embodiment of the present invention;
[0074] FIG. 1D shows a side view of a two-electrode layer capacitive touch screen according to another embodiment of the present invention;
[0075] FIG. 1E shows a side view of a two-electrode layer capacitive touch screen according to an embodiment of the present invention;
[0076] FIG. 2A shows an electrode pattern of drive electrodes with resistive elements according to an embodiment of the invention;
[0077] FIG. 2B shows a portion of the electrode pattern shown in FIG. 2A with a meander pattern of electrode material;
[0078] FIG. 2C shows a portion of the electrode pattern shown in FIG. 2A with screen printed resistors;
[0079] FIG. 2D shows a portion of the electrode pattern shown in FIG. 2A with discrete resistors;
[0080] FIG. 3 shows a portion of the electrode pattern shown in FIG. 2B .
[0081] FIG. 4 shows a portion of the electrode pattern of drive electrodes according to an embodiment of the invention;
[0082] FIG. 5A shows a portion of the electrode pattern shown in FIG. 2A ;
[0083] FIG. 5B shows a typical finger tip;
[0084] FIG. 6 shows an electrode pattern of drive electrodes according to an embodiment of the invention;
[0085] FIG. 7A shows an electrode pattern of sense electrodes according to an embodiment of the invention;
[0086] FIG. 7B shows a two-electrode layer capacitive touch screen according to an embodiment of the present invention with drive and sense units connected via channels to a controller;
[0087] FIG. 8A shows schematically in plan view a portion of the electrode pattern shown in FIG. 7A with infilling electrodes;
[0088] FIG. 8B is a cross-section through a part of FIG. 8A illustrating capacitive paths between infilling electrodes and an X electrode;
[0089] FIG. 9 shows hand-shadow caused by a proximate location of the palm, thumb, wrist etc to a touch screen when the user touches with a finger;
[0090] FIG. 10 shows a portion of the electrode pattern shown in FIG. 7A with infilling electrodes;
[0091] FIG. 11 shows a portion of an electrode arrangement of sense electrodes;
[0092] FIG. 12 shows a two-electrode layer capacitive touch screen according to another embodiment of the present invention; and
[0093] FIG. 13 shows a two-electrode layer capacitive touch screen according to an embodiment of the present invention with drive and sense units connected via channels to a controller.
DETAILED DESCRIPTION
[0094] Described herein is a two-electrode layer construction for a capacitive touch screen or 2DCT sensor.
[0095] FIGS. 1A and 1B are schematic drawings in side view and perspective view of a two-electrode layer construction for a capacitive touch screen or 2DCT sensor. The layers 101 can generally be made of any conductive material and the layers can be arranged to oppose each other on two sides of any isolating substrate 102 such as glass, PET, FR4 etc. The thickness of the substrate 103 is non critical. Thinner substrates lead to higher capacitive coupling between the layers which must be mitigated in the control chip. Thicker substrates decrease the layer to layer coupling and are generally more favorable for this reason (because the measured change in capacitance is a larger fraction of the layer-to-layer capacitance so improving signal-to-noise ratio). Typical substrate thickness' range from 10's to 100's of μm. Furthermore it will appreciated that a dielectric or isolating layer may be disposed overlying the two-electrode layer construction on Layer 2 to prevent an object adjacent the 2DCT sensor making contact with the surface of the layers. This isolating layer might be a glass or plastics layer.
[0096] FIG. 1C shows the side view of an alternative arrangement to the two-electrode layer construction for the capacitive touch screen or 2DCT sensor shown in FIG. 1A according another embodiment of the present invention. In FIG. 1C the layers 101 are disposed on the same surface of the isolating substrate 102 , separated by an isolation layer 108 . An additional dielectric or isolating layer 104 is disposed on the electrodes layers to prevent an object adjacent the 2DCT sensor making contact with the layers surface.
[0097] FIG. 1D shows the side view of an alternative arrangement to the two-electrode layer construction for the capacitive touch screen or 2DCT sensor shown in FIG. 1A according another embodiment of the present invention. In FIG. 1D the layers 101 are disposed on the same surface of the isolating substrate 102 , separated by an isolation layer 108 . However, the electrode layers 101 are disposed on the surface of the isolating substrate that is farthest from the touch surface 106 . A display panel 100 is also shown (with hatching) arranged below the substrate 102 that bears the electrode layers 101 . It will be understood that the display panel in combination with the touch sensor make a touch screen. A display panel could also be fitted to an arrangement as shown in FIG. 1C above.
[0098] FIG. 1E shows the side view of an alternative arrangement to the two-electrode layer construction for the capacitive touch screen or 2DCT sensor shown in FIG. 1A according another embodiment of the present invention. In FIG. 1E each of the layers 101 are disposed on a surface of two different isolating substrates 102 . The two isolating substrates are brought together such that the two electrode layers 101 are separated from the touch surface 106 and are separated by one of the isolating substrates. A display panel could also be fitted to an arrangement as shown in FIG. 1E .
[0099] FIG. 2A shows an electrode pattern of drive electrodes with resistive elements according to an embodiment of the invention. Layer 1 is the layer farthest from the touch surface. On Layer 1 is an array of transmitting electrodes as shown in FIG. 2A . The electrodes 201 are arranged as a series of solid bars running along a first axis 202 or a first direction. A subset of the bars 203 is connected to the control chip so that they can be driven as the transmitter in the transmit-receive arrangement described above. The driven bars 203 include the outer most bars and then an even gap 204 between the remaining driven bars. The intermediate bars 205 are connected using resistive elements 206 in a chain 210 , the ends of the chain being connected to two adjacent driven 203 bars. The driven bars 203 will be referred to as driven-X-bars and the resistively connected bars 205 will be referred to as resistive-X-bars.
[0100] FIGS. 2B , 2 C and 2 D show three different ways in which to form the resistive elements 206 . Namely, the resistive elements 206 can be formed using the intrinsic resistance of the electrode material itself in a “meandered” pattern 207 at the edge of the touch screen (see FIG. 2B ), or can be screen printed resistive material 208 at the edge (see FIG. 2C ), or can be physical discrete resistors 209 either at the edge of the pattern (see FIG. 2D ) or on a separate circuit. The latter option increases the interconnecting wiring substantially but can be advantageous in some designs.
[0101] The resistive chain 210 is used to act as a classic potential divider, such that the amplitude of the transmit signal is progressively attenuated between one driven-X-bar and the adjacent driven-X-bar. The set of driven and resistive bars so described will be referred to as a “segment” 211 . Using this chain, if say driven-X-bar # 1 303 is driven with a pulse train 305 relative to 0V 306 with a peak-to-peak voltage V 307 , and driven-X-bar # 2 304 is driven to 0V, then resistive-X-bars in between these two will be ratiometrically attenuated.
[0102] FIG. 3 shows a portion of the electrode pattern shown in FIG. 2B in which example, if there were 2 resistive-X-bars 205 and the resistor divider chain 210 is constructed of equal valued elements R 308 , then the resistive-X-bar # 1 301 will have a peak-to-peak voltage of 0.66666V and resistive-X-bar # 2 302 will have a peak-to-peak voltage of 0.33333V. This has the effect of progressively weakening the electric field emitted from these resistive electrodes and so forms an interpolating effect for the capacitive changes within the segment between driven-X-bars. Hence, the linearity of the capacitive changes when moving within a segment is improved. Operating without resistive-X-bars is possible but the linearity is poor because the electric field decays over distance in a strongly non-linear fashion. By introducing evenly spaced resistive emitters emitting at an amplitude that is a linear division from the associated driven-X-bar, the field tends to “fill in” and form a better approximation to a linear system.
[0103] In the forgoing description Layer 1 is a pattern of transmit-electrodes, which may also be referred to as drive electrodes. The electrode pattern of Layer 1 may also be referred to as X-electrodes. The drive electrodes include the driven-X-bars 203 and the intermediate X bars 205 or resistive-X-bars. Furthermore, the driven or drive electrodes are defined as being made up of outer most driven-X-bars 203 and intermediate X bars or resistive-X-bars 205 connected using resistive elements 206 in a chain 210 . The outer most X bars are referred to as driven-X-bars 203 . However, it will be appreciated that all of the X-bars might be driven X-bars without using resistive elements.
[0104] Typical resistive elements 206 have resistive values ranging from a few KΩ up to high 110's of KΩ. Lower values require more current (and hence energy) to drive from the control chip but allow faster capacitive measurements as they have lower time constants and hence can be charged and discharged faster. Higher values require less current (and hence energy) to drive but have higher time constants and hence must be charged and discharged more slowly. Larger values also help to make any resistance build up in interconnecting wiring contribute a smaller voltage drop to the emitted field strength from the X bars, and hence make for a more efficient system. For this reason, generally higher values are preferred.
[0105] Another key reason to include the resistive-X-bars is that it makes the segment scalable, i.e. by adding more resistive-X-bars the segment can be made larger. This is at the expense of spatial resolution; the segment uses the same two driven-X-bars and hence the resolution of the measurement must be fundamentally the same, but the segment is now spread across a larger region and so spatially the resolution degrades. Making the segment scalable means that fewer driven-X-bars are needed and hence fewer connections to the control chip. By balancing the trade-off between spatial resolution and connection cost/complexity an optimal solution may be found for each design.
[0106] Overall, the bars in Layer 1 can be seen to be substantially area filling; almost all of the surface area is flooded with electrode. The gaps between the bars 205 can be made arbitrarily small and indeed, the smaller the better from a visibility point of view. Making the gaps larger than around 100 μm is non-ideal as this leads to increased visibility of the gap to the human eye and a key goal is often to try and make an invisible touch screen. A larger gap also tends to increase the possibility of a significant fringing electric field near the gap to electrodes in Layer 2 which will lead to worsening non-linearity. Gaps of a few 10's of micrometers are common as they are almost invisible and can be easily mass-produced, for example gaps of between 20 and 50 micrometers.
[0107] FIG. 4 shows a portion of the electrode pattern of drive electrodes according to an embodiment of the invention. Referring to FIG. 4 , it is also desirable to use a gap with a small up/down wave pattern 401 between driven 402 and resistive-X-bars 403 as this helps to disguise the gap when viewed through Layer 2 with the added effect of the parallax caused by the substrate thickness. Various patterns can be used to help disguise the gap when viewed in this way, for example a sine wave, triangle wave or square wave could be used. The frequency and amplitude are chosen to help break up the otherwise long linear gap when viewed through the complex but regular pattern in Layer 2 . The amplitude must be minimized to avoid errors in the reported touch coordinate.
[0108] FIG. 5A shows a portion of the electrode pattern shown in FIG. 2A .
[0109] FIG. 5B shows a typical finger tip.
[0110] The electrode bars (both types) are generally designed so that they have a fundamental pitch of around 8 mm or less, as shown in FIG. 5A preferably 5 mm. This is in recognition that, as shown in FIG. 5B , a typical finger touch 501 creates a generally circular region 502 (illustrated in FIG. 5B with hashing) of around 8 to 10 mm in diameter and so matching the electrode pitch to the touch size optimizes the interpolating effect of the touch. Making the pitch of the electrodes larger than 8 mm can start to lead to distinct non-linearity in the response as the interpolation is well below ideal. In essence, by making the electrode bars too wide, as the touching finger moves perpendicular to the bars its influence tends to “saturate” over one electrode before it starts to interact with the next electrode to any significant degree. When the pitch is optimized, the finger will cause a steadily reducing influence on one bar while already starting to create a well balanced increase on the neighboring bar, with the peak influence being spatially quite distinct i.e. steady increase immediately followed by steady decrease with no appreciable transition distance from increase to decrease (or vice-versa).
[0111] FIG. 6 shows an electrode pattern of drive electrodes according to an embodiment of the invention. Referring to FIG. 6 the driven-X-bars at the outer edges of Layer 1 601 are made to be half the width of all other bars 602 . The overall design is in essence several identical concatenated segments 603 , and the driven-X-bars on the inside of the layer 604 are also half width but are butted up to the neighboring segment with its half width outer bar, so driven-X-bars internal to the pattern appear to be full width. FIG. 6 shows the virtual division of the internal bars 604 with a dashed line; in practice of course the bars 604 are one-piece. Having the pattern at its outer two edges with half-width bars improves the overall linearity; if the pattern were infinite then the linearity would be perfect in this regard, but of course the pattern must end and hence there is a natural non-linearity at the edges.
[0112] FIG. 7A shows an electrode pattern of sense electrodes according to an embodiment of the invention. Layer 2 is the layer nearest to the touch surface. Referring to FIG. 7A in its simplest form, the electrodes on Layer 2 are a uniformly spaced series of narrow lines running along a second axis at nominally 90 degrees to the first axis used in Layer 1 herein referred to as a second direction. That is to say that the Layer 1 or drive electrodes cross the Layer 2 or sense electrodes. The electrodes on Layer 2 are referred to as sense electrodes, Y-electrodes, Y lines or receive electrodes. They are arranged to lie directly and completely over the area 703 occupied by the X bars underneath. The spacing between the Y lines has a similar influence on the linearity as does the spacing of the X bars. This means that the Y lines need to be spaced with a pitch of 8 mm or less 704 , preferably 5 mm for best intrinsic linearity. In a similar way to the Layer 1 with its half-width outer X bars, the gap from the edge of the Layer 2 pattern to the first line is half of this pitch 705 to improve the linearity. The width of the Y lines 706 is important. They need to be narrow enough so that they are not easily visible to the human eye, but wide enough that they have a resistance (at their “far-end”) that is low enough to be compatible with capacitive measurements. Narrower is also better as far as noise immunity is concerned because the surface area of the Y line has a direct influence on how much electrical noise can be coupled into the Y lines by a finger touch. Having narrower Y lines also means that the capacitive coupling between the X and Y layer is minimized, which, as previously mentioned, helps to maximize signal-to-noise ratio.
[0113] FIG. 7B shows a touch sensor 10 according to an embodiment of the invention. The sensor 10 shown in the figure combines the electrode patterns from FIG. 2A and FIG. 7A . The sensor 10 comprises a substrate 102 bearing an electrode pattern 30 defining a sensitive area or sensing region of the sensor and a controller 20 . The controller 20 is coupled to electrodes within the electrode pattern by a series of electrical connections which will be described below. The electrode pattern 30 is made up of Layer 1 electrodes and Layer 2 electrodes on opposing sides of the substrate 102 as shown in FIG. 1B .
[0114] Referring to FIG. 7B , the controller 20 provides the functionality of a drive unit 12 for supplying drive signals to portions of the electrode pattern 30 , a sense unit 14 for sensing signals from other portions of the electrode pattern 30 , and a processing unit 16 for calculating a position based on the different sense signals seen for drive signals applied to different portions of the electrode pattern. The controller 20 thus controls the operation of the drive and sense units, and the processing of responses from the sense unit 14 in the processing unit 16 , in order to determine the position of an object, e.g. a finger or stylus, adjacent the sensor 10 . The drive unit 12 , sense unit 14 and processing unit 16 are shown schematically in FIG. 7B as separate elements within the controller. However, in general the functionality of all these elements will be provided by a single integrated circuit chip, for example a suitably programmed general purpose microprocessor, or field programmable gate array, or an application specific integrated circuit, especially in a microcontroller format.
[0115] In the figure there is provided a number of drive electrodes 60 represented by longitudinal bars extending in the x-direction as described above and shown in FIG. 2A . On the opposing surface of the substrate 102 , there is provided a number of sense electrodes 62 forming electrode Layer 2 as shown in FIG. 7A and described above that cross the drive electrodes 60 of Layer 1 in the y-direction.
[0116] The sense electrodes are then connected to the sense unit 14 via connections or tracks 76 and the drive electrodes are connected to the drive unit 12 via connections or tracks 72 . The connections to the drive and sense electrodes are shown schematically in FIG. 7B . However, it will be appreciated that other techniques for routing the connections or tracks might be used. All of the tracks might be routed to a single connector block at the periphery of the substrate 102 for connection to the controller 20 .
[0117] The operation of the sensor 10 shown in FIG. 7B is described below. As can be seen there are conflicting requirements for the Y lines in terms of their width. The strongest requirement tends to be the minimization of the resistance of the Y line to ensure successful capacitive measurement within an acceptable overall measurement time. This leads to wider electrodes, typically in the region of 100 μm to 1000 μm. Where the visibility of the electrodes is either not an issue or where the electrodes can be made practically invisible (such as index matched ITO on PET for example), then the compromises are all quite easily accommodated and the width increase is a simple choice. But where the visibility is an issue and the method used to fabricate the electrodes cannot be made sufficiently invisible (such as non index matched ITO on glass) then some alternative arrangement must be found. In this case, a method called in-filling can be used as now described and illustrated.
[0118] FIG. 8A shows a portion of the electrode pattern shown in FIG. 7A with infilling electrodes. This method fills all “unused” 801 space with isolated squares of conductor 802 (ITO for example), separated with gaps 803 to its neighbors that are small enough to be practically invisible and small enough to cause significant square-to-square capacitance. Another key factor in designing the isolated elements or islands is to make them the same size 804 in each axis as the width of the Y lines 805 . In this way, the uniformity of the overall pattern is optimal, and the only irregularity is in the length of the Y lines. This pattern is substantially invisible to the human eye. The gaps between neighboring squares, and the gaps between squares and neighboring Y lines can be made arbitrarily small, typically in the region of 10's of μm as they are almost invisible and can be easily mass-produced. The in-filling is generated during manufacture at the same time, and using the same process steps, as the sense electrodes, so they are made of the same material and have the same thickness and electrical properties as the sense electrodes. This is convenient, but not essential. The in-filling could be carried out separately in principle.
[0119] The isolated squares 802 serve to obscure the overall pattern but they also act as a capacitive interpolator (somewhat analogous to the resistive interpolator used in Layer 1 ). The capacitive interpolator so formed has the effect of only minimally impacting the fringing fields between the Y line and the underlying X bars. This is important because the field must spread out down to the X bars sufficiently from the edges of the Y lines to allow a substantial touch influence over at least half the pitch of the Y lines. This holds true so long as the capacitance from square to square is substantially higher (at least ×2) the capacitance of a square down to the X bars. The reason for this is that under these conditions the electric field tends to propagate from square to square more easily than it is shunted down to the X layer. As a result, the field distributions of a design with no in-fill compared to one with in-fill are similar enough that the linearity is preserved. If the square-to-square gaps are increased, the linearity degrades because the field tends to pass via the first couple of squares away from a Y line down to the X bars and so does not propagate far from the Y line.
[0120] FIG. 8B illustrates these capacitive paths between example infilling electrodes and between an example infilling electrode and an example X electrode. Capacitance from square 808 to square 808 is shown with nominal capacitors 806 and capacitance from one of the squares 808 down to an adjacent X bar 809 is shown with nominal capacitor 807 .
[0121] It should be noted that the in-fill is not actually needed in this design, but it can be used to minimize pattern visibility without compromising the linearity of the output.
[0122] In operation the transmitting or drive electrodes are sequenced such that only one driven-X-bar 203 is ever active at one time, all others being driven to a zero potential. The field emitted therefore only radiates from one segment at a time. This radiated field couples locally into all of the Y lines 701 above the segment in question. The control chip then takes a capacitive measurement for each of the “intersections” or “crossings” formed between the X and the Y electrodes in this segment. Each XY intersection is also known as a node. In sequence, each driven-X-bar is activated, holding all others at zero potential. In this way, each segment is sequentially scanned. Once all segments have been completed, a total of N×M nodes will have been measured where N is the number of driven-X-bars and M is the number of Y lines. It should be stressed that the node measurements are all independent of each other making it possible to detect several touch locations simultaneously. Another important point in the way the XY array is scanned is that because only one segment is active at any one time, the others being driven to zero potential, only touches in the active segment can influence the measured node capacitances in that segment (at least to a first approximation). This means that an effect known as “hand-shadow” is strongly minimized. Hand-shadow is an effect caused by the proximate location of the palm, thumb, wrist etc to the touch screen when the user touches with a finger.
[0123] FIG. 9 shows hand-shadow caused by a proximate location of the palm, thumb, wrist etc to a touch screen when the user touches with a finger. The nature of capacitive measurement means that the electric fields tend to radiate or project from the surface of the device and so can be influenced even by objects that are not in direct contact with the surface. This influence would normally serve to distort the reported touch location, as the combined capacitive readings of the finger together with readings caused by the “hand shadow” would slightly corrupt the computed coordinates reported by the control chip. By activating only one segment at a time this normally problematic effect is drastically reduced.
[0124] Having scanned the entire touch screen, generating N×M node measurements, it is a simple task to compute the touch location, in both of the axes, of one or more objects, as described in U.S. patent application 60/949,376 published as WO 2009/007704 on 15 Jan. 2009, using a combination of logical processing to discover the node at the approximate centre of each touch, and standard mathematical centroid computations of the relative signal strengths around each touch detected. The touch location along the first axis is resolved using the touch's centre node signal and the immediately adjacent node signal to each side that lie along the first axis. Likewise, the location in the second axis is resolved using the centre node and the immediately adjacent node signals that lie along the second axis.
[0125] A key design advantage in having the entire Layer 1 almost entirely covered or flooded with emitting X electrodes is that because these electrodes are virtually immune to changes in parasitic capacitive loading (they are relatively low impendence drivers, even the resistively coupled X bars still only have DC resistances of a few 10's of KΩ and so can charge and discharge any moderate parasitics very quickly) any change in the distance between the rear (non-touch side) of Layer 1 and a nearby ground load will make no difference to the measured capacitances of the nodes. The touch screen is thus touch-sensitive only on one side, Layer 2 . This has major benefits when slightly flexible front panels are used that can bend relative to an LCD placed below the touch screen. The separation between Layer 1 and Layer 2 is fixed by the substrate material and hence the capacitance between these two is fixed even if the substrate is bent during touch causing the rear of Layer 1 to experience a change in its ambient conditions.
[0126] A further advantage to using the flooded X design is that it provides an inherent amount of noise attenuation for radiated emissions that are present behind Layer 1 . This is common with LCD modules that tend to have large amplitude drive signals present on their outer layers. These drive waveforms will normally couple to the Y lines and disturb the momentary reported capacitance of the associated nodes. However, because the Y lines are effectively shielded by the flooded X layer, the only remaining mechanism for the noise to couple to the Y lines is capacitively via the X layer itself. The X bars, as already described, are reasonably low resistance and so can only be disturbed by the interfering noise waveform in proportion to the ratio of the impedance of the noise coupling vs. the impedance of the X bar. Hence, the amount of noise coupled onward to the Y lines is attenuated by this ratio. The coupling of the noise waveform to X bars is purely capacitive and so decreasing this coupling capacitance helps to attenuate the interference even more. This can be achieved by arranging an air gap between the LCD and the back of Layer 1 , or by using a transparent dielectric spacer layer instead of the air gap that will yield a higher capacitance of coupling but has the advantage of being mechanically robust. In a traditional capacitive touch screen an entire extra “shielding” layer below Layer 1 must often be used to mitigate this LCD noise. This layer is often driven to zero potential or is actively driven with a facsimile or copy of the capacitive acquisition waveform, which serves to isolate the noise from the capacitive nodes. This has the disadvantage of adding cost and complexity, worsens optical properties and also tends to attenuate the size of the change in capacitance during touch (leading to lower resolution and worse signal-to-noise ratio). The flooded X design described herein will often produce sufficient inherent attenuation of the coupled noise that no extra layer is required, offering a substantial commercial advantage.
[0127] Another advantage found with this design is that the Y lines can be made narrow in comparison to the size of the touching object. In particular, the Y lines can have a width of one quarter or less than the size of the touching object, or equivalently the pitch of the X electrodes. For example, a Y line width of 0.5 mm is 16 times narrower than the width of a typical finger touch. The implication of this is related to the surface area available for interaction with the touching finger. A narrow Y line has a very small surface area to couple capacitively to the touch object; in the example cited, the coupled area is around 4 mm 2 compared with the total “circular” touch area of around 50 mm 2 . With such a small area coupled to the touch, the amount of noise injected into the Y line from the finger is minimized because the coupling capacitance is small. This has an attenuating effect on any differential noise between the touch object and device using the touch screen. Furthermore, by making narrow Y lines the resistance is reduced. Reducing the resistance of the Y lines reduces the acquisition times and decreases the power dissipation.
[0128] In summary, the advantages of the described touch screen are:
1. Only two layers are required for construction leading to; (i) improved optical transmission (ii) thinner overall construction (iii) lower cost. 2. Area filling design for electrodes on Layer 1 leading to; (i) almost invisible electrode pattern when using ITO (ii) isolation of the Y lines on Layer 2 from capacitive effects below Layer 1 (iii) partial attenuation of noise coupled from an underlying LCD module or other noise source. 3. Narrow Y lines on Layer 2 with optional area filling isolated squares leading to; (i) almost invisible electrode pattern when using ITO (ii) reduced electrode area reduces susceptibility to coupling noise from touch.
[0132] In some designs it may be desirable to minimize the number of Y lines used across Axis 1 —labeled the first axis in FIG. 7A . This generally leads to a lower cost control chip and simplifies interconnection of the electrodes. With the described Y line design, the fundamental pitch between lines needs to be 8 mm or below to achieve good linearity. Spacing the lines further apart rapidly compromises linearity in Axis 1 . To enable the Y lines to have a greater “reach” there are several adaptations that can be made to the Layer 2 design.
[0133] FIG. 10 shows a portion of the electrode pattern shown in FIG. 7A with infilling electrodes according to a first option. The first option shown in FIG. 10 is to use the capacitive interpolator technique previously described with the square-to-square gap 1001 reduced to allow the electric field to propagate further away from the Y line and so allow a larger pitch 1002 between Y lines 1003 . This technique may require that the ratio of capacitance between squares vs. square to X bars must be carefully tuned to achieve the best linearity.
[0134] FIG. 11 shows a portion of an electrode arrangement of sense electrodes according to a second option and more flexible option which modifies the Y line 1101 design to add a series of cross-members 1102 running along the first axis 1103 and equally disposed 1104 so as to be centered about the Y line. The cross members span approximately ½ to ¾ of the gap to the next Y line 1105 in both directions. The cross members on each successive Y line are arranged so that they overlap the cross members of those on the neighboring Y lines 1106 with the gap 1107 between the overlapping sections chosen to be a few 10's of μm to minimize visibility and prevent any substantial fringing fields from forming along the inside of the overlapped region. The cross members are spaced by a distance 1108 along the Y line on a pitch of 8 mm or less, and ideally they are spaced to lie with a uniform relationship to the gaps in the underlying X bars. This ensures that the field patterns are uniform and symmetrical in all regions of the touch screen, leading to good linearity. The cross members effectively act to spread the electric field further beyond the primary Y line and the overlapped region helps to gradate the field from one Y region to the next in a linear fashion.
[0135] Embodiments of the invention shown in FIGS. 2A , 7 A, 7 B and 11 may further comprise connections to both extents of the drive and sense electrodes or transmitting electrodes and Y lines respectively. That is to say that a connection is made at both ends of each of the drive and sense electrodes. This may increase the linearity of the electric filed along the drive electrodes and improve the shielding of the flooded electrode design.
[0136] Embodiments of the invention may also be applied to non-display applications, for example touch pads on a laptop or control panels on domestic appliances.
[0137] FIG. 12 shows a sensor 80 comprising an electrode pattern according to an embodiment of the invention. For simplicity the electrode pattern shown in the figure does not include any circuitry. However, it will be appreciated that drive and sense circuitry may also be used as described above for the FIG. 7B embodiment. The figure shows an electrode pattern on opposing sides of a substrate 82 , viewed from above to show the relative position of the electrode patterns.
[0138] The electrode pattern comprises two annular electrodes of the type described above referred to as Layer 1 or transmit electrodes. The transmit electrodes may also be referred to as drive electrodes. The drive electrodes 84 shown in the figure are effectively the transmit electrodes shown in FIG. 2A and have been wrapped around arcuately to form a complete, or near complete, ring or annulus, as might be used by a scroll wheel sensor for example. Connected to each of the drive electrodes 84 is a connection or track 90 to provide a drive signal from an appropriate drive unit (not shown). The drive unit described above may be used. The electrode pattern further comprises a number of sense electrodes referred to above as Layer 2 electrodes 86 which extend radially from a central point. The Layer 2 electrodes may also be referred to as sense electrodes or receive electrodes. The sense electrodes 86 are in the form shown in FIG. 11 and described above. The sense electrodes are connected to a sense unit (not shown) via connections or tracks (not shown). The operation of the sensor 80 is similar to that described above. However, the readout from a processing unit (not shown) connected to the drive and sense units will be different. The output of the processing unit will provide a polar co-ordinate of an object adjacent the sensor 80 . The sensor 80 shown in FIG. 12 may be used in an application where two circular controls are typically used in combination, for example the bass and treble controls or the left/right and front/rear fade controls on a hi-fi amplifier. It will be appreciated that further annular shaped drive electrodes may be implemented in the sensor 80 shown in the figure. This embodiment may therefore be summarized as following a polar coordinate grid, with the two electrode types extending radially and arcuately, in contrast to the other embodiments which follow a Cartesian coordinate grid, with the two electrode types extending along the x- and y-axes.
[0139] In a modification of the FIG. 12 design, the arcuate path may extend over a smaller angle for example a quarter or half circle instead of a full circle, or another angular range.
[0140] FIG. 13 is a view of a front side of a position sensor 10 according to an embodiment of the invention. The same reference numerals used in FIG. 7B are used in reference to the sensor 10 shown in FIG. 13 where appropriate. The position sensor shown in FIG. 13 is similar to the sensor shown in FIG. 7B in layout and operation. However, the position sensor shown in the figure has an alternative arrangement of electrodes. The drive and sense electrodes shown in the figure are made up of thin wires or a mesh of wire instead of the continuous layer of electrode material shown in FIG. 7B . The drive electrodes 60 are made up of a rectangular perimeter to define the shape of the drive electrode with a series of diagonal lines going across the rectangular perimeter. The diagonal lines are typically arranged at an angle, preferably approximately 45±15 degrees, to an axis in extending in the x-direction. The diagonal lines and the rectangular perimeter of each drive electrode are electrically connected and connected to the drive unit 12 via the drive channels 72 . The wires or mesh are manufactured from high electrical conductivity material such as metal wires, where the metal is preferably copper, but could also be gold, silver or another high electrical conductivity metal. The sense electrodes are manufactured in a similar way using thin metal traces that follows the perimeter of the sense electrode pattern shown in FIG. 7B . The sense electrodes 62 are relatively narrow compared to the drive electrodes 60 , so there is no need to use in-filling with diagonal lines. However, some extra wires are added within the sense electrode mesh structure as shown in FIG. 13 by lines 64 which bridge between peripheral wires in each electrode. These bridge wires add redundancy in the pattern in the sense that if there is a defect in a peripheral wire at one location, the current has an alternative path along the electrode. By defect we mean a break, local narrowing or other feature that causes a severe reduction in the local conductivity along a wire. Such defects can occur, for example, as a result of errors in the electrode patterning process. For example, if there is a defect in the optical mask used to pattern the wires or if there is debris on the surface of the wires during processing then defects can arise.
[0141] It will be understood that the “mesh” or “filligrane” approach to forming each electrode out of a plurality of interconnected fine lines of highly conducting wire or traces may be used for either Layer 1 (flooded X drive), Layer 2 (sense) or both. The FIG. 13 embodiment uses meshes for both layers. However, a particularly preferred combination for display applications or other applications where invisibility is important is that Layer 1 is made with non-mesh, i.e. “solid” electrodes with the small, invisible gaps, for example from ITO, and Layer 2 is made with mesh electrodes, for example out of copper, having line widths sufficiently small to be invisible also.
[0142] It will also be understood that the mesh approach of the embodiment of FIG. 13 can be used in a design of the kind illustrated in FIG. 11 and FIG. 12 in which the sense electrodes have overlapping branches.
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A capacitive touch sensor wherein the touch sensitive panel has drive electrodes arranged on the lower side of a substrate and sense electrodes arranged on the upper side. The drive electrodes are shaped and dimensioned to substantially entirely cover the touch sensitive area with individual drive electrodes being separated from each other by small gaps, the gaps being so small as to be practically invisible. The near blanket coverage by the drive electrodes also serves to screen out interference from noise sources below the drive electrode layer, such as drive signals for an underlying display, thereby suppressing noise pick-up by the sense electrodes that are positioned above the drive electrodes.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a readherable, repositionable and reusable adhesive fabric paper that is used to color printers for personal computers, printing machines for indoor and outdoor advertising, wide format printers, plotters, and so on to print colored images.
2. Background Art
More particularly, the present invention is characterized in that the adhesive fabric paper allows any printer to easily print, can be freely readhered onto many places several times, does not leave an adhered mark when it is come off, and does not damage a place where this product will be adhered (for instance, on a painted wall, on wallpaper, or on an existing advertising medium previously attached to any one place).
Furthermore, the present invention is characterized in that the adhesive fabric paper is soft and reusable several times, allows a higher resolution image and a superior image quality, and prevents decoloration of printed images. Moreover, the adhesive fabric paper according to the present invention has an effect for shading the sun by adding a gray coating on the rear face of the fabric through a special technique to thereby allow an easy window decoration in the summer season, and can protect a human body since the fabric and an adhesive layer of this product can serve to fix broken window pieces to a certain extent when a window is broken.
Additionally, the adhesive fabric paper according to the present invention is a superior product in various aspects including a cutting work.
In general, paper and vinyl are mainly used for printing. However, recently, with a development of various advertising techniques, printing methods to print on fibrous materials is increasing.
As a representative example, there are banners that are recently used to output images through a wide format printer or a plotter.
However, such fabrics for printing have several problems in that the degrees of clarity and detail are low due to a low printing quality, in that it is decolorated rapidly after the printing, in that it requires thermal cutting that is expensive and takes much time since yarns of a cut portion are unloosed when the fabric is cut as much as a necessary size, and in that it is inconvenient to adhere and remove an advertising thing.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior arts, and it is an object of the present invention to provide a readherable, repositionable and reusable adhesive fabric paper, which is fit to a new advertising period, can reduce a customer's burden on costs a bit, allows the customer to easily and directly carry out printing, allows a higher resolution image and a superior image quality, and prevents decoloration of printed images.
Furthermore, it is another object of the present invention to provide a readherable, repositionable and reusable adhesive fabric paper, which has an effect for shading the sun to thereby allow an easy window decoration in the summer season, can protect a human body when a window is broken, and is easy to cut.
To accomplish the above object, according to the present invention, there is provided a method for manufacturing a readherable, repositionable and reusable adhesive fabric paper for printing images, comprising the processes of: heating and cooling rapidly a woven fabric so that its width is shrunk by 10% to 15%; preparing a first “S” coating liquid containing ethylene vinyl acetate copolymer of 40˜50% by weight, a second “S” coating liquid containing polyurethane resin of 25% by weight, and an “R” coating liquid containing low molecular alcohol of 60˜75% by weight and silicon dioxide (silica) of 8˜12% by weight as coating liquids to be coated on the front face of the fabric, and maturing them for three days; coating twice the rear face of the fabric with a mixture in which polyurethane resin and a white pigment are mixed together, and coating once the rear face of the fabric with a mixture in which polyurethane resin and a gray pigment are mixed together; coating the front face of the fabric using the prepared “S” coating liquids and the “R” coating liquid, wherein a first coating is carried out using the first “S” coating liquid, a second “S” coating is carried out using the second “S” coating liquid, and the “R” coating liquid is coated on the front face of the fabric twice; and laminating a backer coated with an adhesive to the coated fabric.
The adhesive fabric paper according to the present invention allows any printer to easily print, can be freely readhered onto many places several times, does not leave an adhered mark when it is come off, and does not damage a place where this product will be adhered (for instance, on a painted wall, on wallpaper, or on an existing advertising medium previously attached to any one place).
Furthermore, the adhesive fabric paper according to the present invention is soft and reusable several times, allows a higher resolution image and a superior image quality, and prevents decoloration of printed images. Moreover, the adhesive fabric paper according to the present invention has an effect for shading the sun by adding a gray coating on the back of the fabric through a special technique to thereby allow an easy window decoration in the summer season, and can protect a human body since the fabric and an adhesive layer of this product can serve to fix broken window pieces to a certain extent when a window is broken.
Additionally, the adhesive fabric paper according to the present invention is a superior product in various aspects including a cutting work.
Accordingly, the adhesive fabric paper for printing according to the present invention is a convenient product, which is freely readherable to various places for indoor and outdoor advertisings, such as commercial advertising, domestic printing paper, wallpaper decoration, advertising of various kinds using vehicles, picketing, postcards, bromides, and so on.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:
FIG. 1 is an enlarged sectional view of an adhesive fabric paper according to the present invention; and
FIG. 2 is another enlarged sectional view of the adhesive fabric paper according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will be now made in detail to the preferred embodiment of the present invention with reference to the attached drawings.
It is the best to use polyester DTYs (Draw Textured Yarns) for a fabric.
The reason is that the polyester DTYs can absorb a coating liquid deepest of fabrics all when the coating liquid for receiving ink sufficiently is coated on the fabric during a manufacturing process of an adhesive fabric paper according to the present invention, and make the coating liquid exist between pieces of yarns to thereby prevent the coating liquid from being separated from the fabric supremely after coating.
Moreover, the polyester DTYs can allow a print ink to be evenly and deeply distributed on the coating liquid sufficiently absorbed into the fabric and existing between the pieces of yarn to thereby provide excellent image resolution and vividness.
The polyester DTYs are woven with the warp of 75 denier per 36 filaments and the weft of 150 denier per 48 filaments wherein the warp density is about 8,800 yarns and the weft density is 72 T per inch.
Furthermore, the polyester DTYs may be woven with the warp of 75 denier per 72 filaments and the weft of 75 denier per 72 filaments.
Next, the fabric is heated and cooled rapidly so that its width is reduced by 10% to 15%. There are various heating methods, but in this invention, a JIG type machine is used, and in this instance, the fabric is treated for 7 to 8 hours while keeping temperature of 180° C. when the width of the fabric is 74 inches.
After the above process, the fabric is cooled rapidly to thereby be shrunk. The rapidly cooling process is carried out twice in such a way that the fabric is shrunk sufficiently till it becomes a 74-inch fabric with a width ranging 64 inches to 65 inches.
Then, the fabric density gets higher so that yarns close together and get dense, and hence, it can be prevented that the coating liquid is permeated to the rear face of a coated face during a rear face coating process, which will be carried out later.
It also can prevent the curling of the fabric and the tunneling between the fabric and the backer caused by a shrinkage of the fabric on the backer after this surface-coated product is completely laminated to the backer.
Since fabrics are different in quantity to absorb moisture, they cause the curling and tunneling when they come in contact with paper. Accordingly, when the fabric is matured several times during a sufficient period of time to thereby prevent the shrinkage of the product after the lamination of the product.
To make coating liquid, in this invention, coating liquids of two types are used: one being an “S” coating liquid for solvent-based ink; and the other being an “R” coating liquid for dyes-based ink, pigment-based ink and UV ink.
Prepare the coating liquids before three days from the use. The reason is to mature them for about three days and to make time that different ingredients of the coating liquids react with each other sufficiently.
After that, put a central rotating shaft into a container having the coating liquid therein and sufficiently mix the coating liquid at high speed for about 30 minutes before the use to thereby make viscosity of the coating liquid sufficiently thin and keep its white color evenly.
Particularly, the “S” coating liquid is divided into a first coating liquid and a second coating liquid, which are different coating liquids. Furthermore, the “R” coating liquid is coated twice.
Basic ingredients of the “S” coating liquid are as follows.
<First Coating Liquid>
Chemical characterization CAS NO WT % Ethylene vinyl acetate copolymer 24937-78-8 40~50 additive — 5~10 water 7732-18-5 40~60
<Second Coating Liquid>
Chemical characterization CAS NO WT % Poly urethane Resin 51-79-6 app.25 additive — app.10 Methyl alcohol 67-56-1 app.60
Basic Ingredients of the “S” Coating Liquid are as Follows.
Chemical characterization
CAS NO
WT %
Low molecular alcohol
67-56-1
60~75
Silicon dioxide(silica)
112945-52-5
8~12
Additive
mixture
9~12
Polyacrylate copolymer
—
10~15
To make a treatment of rear face of the fabric, first, mix polyurethane resin and a white pigment together and carry out a white coating (hereinafter, called rear face white coating) to the rear face of the fabric. Next, mix polyurethane resin and a gray pigment together and carry out a gray coating (hereinafter, called rear face gray coating).
The rear face white coating and the rear face gray coating are used as methods for waterproof of umbrellas or parasols for shading the sun because they have strong water resistance. In the present invention, they are used to make an adhesive be coated well and prevent penetration of the adhesive into the fabric in the following process.
If the adhesive penetrates through the fabric, it will be caused that decoloration of an image printed on the front face will be hastened. Moreover, the rear face white coating and the rear face gray coating serve to prevent loosening of yarns when the adhesive fabric paper is cut in a predetermined size and when it is cut in a roll type since they serve to fix yarns.
As described above, the present invention can reduce expenses since it can be cut by a cutting blade, which is inexpensive and fast without needing the expensive heat cutting, which takes much time, due to the rear face white coating and the rear face gray coating serving to prevent loosening of yarns. Additionally, this process is carried out to prevent transmission of light into the fabric and shade the sun.
Especially, this process is also carried out to prevent that the existing background color or pictures or characters of the previously adhered advertisement are shown through on the surface of the present invention when the adhesive fabric paper of the present invention is adhered on a certain place.
In addition, this process is carried out not in such a way as to just form a thin white coating layer and a thin gray coating layer but in such a way as to treat the rear face white coating and the rear face gray coating after respectively mixing the white pigment and the gray pigment with polyurethane resin, and hence, it may give the same effect as that the fabric gets dyed white and gray. Accordingly, since this process increases the effect of the white coating of the front face (“S” coating and “R” coating) and doubles the effect of the gray coating of the rear face, the fabric and the adhesive are cleanly removed together without leaving any gray spot on a wall or a surface when the adhesive fabric paper of the present invention is adhered on and removed from the wall or the surface.
In other words, the present invention can be adhered on the existing and previously adhered advertising thing without any problem in various aspects. Especially, after the above process, carry out the “S” coating and the “R” coating on the opposite face of the face where this process is carried out.
Then, the color of the rear face gray coating does not give any influence and change on the “S”-coated and “R”-coated white face, the “S”-coated and “R”-coated white face can keep its white color more clearly by the rear face white coating, and the characteristic of the rear face gray coating for shading the sun can be kept as it is.
The existing vinyl products require many expenses since they must be used after the previously adhered advertising things and adhered remnants are all removed. Actually, the vinyl products have a problem in that it is inconvenient and complex to adhere it and carry out other works because they leave thin vinyl layers on a wall or an advertising pole when they are removed.
Accordingly, in the present invention, the fabric is laminated with a backer through a removable adhesive, which will be processed in the next process, so that the present invention can be easily removed without any damage to the existing wallpaper or a painted place and without leaving adhered remnants, and is readherable and reusable several times.
This process includes the following steps.
<Rear Face White Coating>
Mix polyurethane resin and the white pigment together in the ratio of 6:4 (For instance, polyurethane resin of 30 g+white pigment of 20 g). The mixture of 50 g is used per 1 yard with the width of 65 inches.
An interval of a coating knife from the surface of the fabric during coating is 0.8 mm during the first cutting and 1 mm during the second cutting, and the room temperature of a drying room for drying the coating liquid is kept in a range of 150° C. to 170° C.
Here, it is important to carry out the coating again through the same process. The reason is that to coat thin twice gives clearer white color than to coat thick once and that the rear face gray coating, which will be carried out next, can minimize transparentness without any influence on the “S”-coated and “R”-coated white surface.
As described above, this step can fix the yarns in such a way that the yarns are not loosed as firm as possible and prevent penetration of the adhesive into the surface since films are formed doubly.
<Rear Face Gray Coating>
Mix polyurethane resin and the gray pigment together in the ratio of 6:4 (For instance, polyurethane resin of 30 g+white pigment of 20 g). The mixture of 50 g is used per 1 yard with the width of 65 inches.
An interval of a coating knife from the surface of the fabric during coating is 0.5 mm during the first cutting and 0.8 mm during the second cutting, and the room temperature of the drying room for drying the coating liquid is kept in a range of 150° C. to 170° C.
This step is carried out once. Differently from the rear face white coating, since the gray pigment used in the rear face gray coating has a high saturation, it can show a satisfied effect through just one coating.
In the process of a surface coating of the fabric, as described above, the “S” coating liquid and the “R” coating liquid, which are different sorts, are used. The “S” coating and the “R” coating are carried out on the opposite face of the face to which the rear face white coating and the rear face gray coating are applied.
In other words, after the white coating and the gray coating are applied to the rear face, the “S” coating and the “R” coating are applied to the opposite face of the rear face (namely, the front face). Accordingly, this process can be carried out easily because the rear face coating liquids are not stained on the surface of the fabric to which the “S” coating and the “R” coating will be applied. Such an effect may be obtained also through the heating process of the fabric, which is described above.
After the first coating, dry and cool the fabric. After that, carry out the second coating, and then dry the fabric.
Particularly, compared with a method that coating ingredients are all mixed together and coating is carried out once, this method to coat and dry twice can make the coating liquid penetrate into the fabric evenly and separate the coating layers from each other, so that the first coating serves as a underpainting and as a medium to fix the fabric in such a way that the second coating liquid does not easily separate from the fabric. Furthermore, the method can prevent an easy decoloration of the surface coating of the fabric even though water permeated.
The second coating serves to absorb ink evenly and to express colors vividly.
Especially, because the second coating is carried out in a cooled condition after the first coating and drying, it can prevent that the coating liquid is coated on the fabric in a lump since the coating liquid is hardened during the second coating directly before it is distributed on the fabric evenly due to heat permeated into the fabric during the first coating. Also, it can minimize formation of coating lines on the surface of the fabric during the coating. In comparison with the method that coating ingredients are all mixed together and coating is carried out once, this method to coat and dry twice can prevent transmission of light by keeping the respective separate coating layers and maximize the effects of the respective coating liquids.
Furthermore, through this method, the second coating liquid can be firmly fixed on the first coating liquid.
Next, how to carry out the “S” coating and the “R” coating will be described.
<First “S” Coating>
The coating liquid of 62 g to 69 g is used per 1 yard with the width of 65 inches, and an interval of a coating knife from the surface of the fabric during coating is 1.5 mm. The room temperature of the drying room for drying the coating liquid is kept in a range of 170° C. to 190° C.
The surface tension of the fabric is kept in a relatively loose condition as much as the knife interval of 1.5 mm so that the coating liquid can be coated satisfactorily. If the surface tension is too strong, the coating liquid is coated too thin and the fabric may be shrunk again after the completion of the product, and hence, the surface tension is to prevent tunneling between the fabric and the backer after the fabric and the backer are laminated together.
<Second “S” Coating>
The coating liquid of 34 g to 41 g is used per 1 yard with the width of 65 inches, and an interval of a coating knife from the surface of the fabric during coating is 2 mm. The room temperature of the drying room for drying the coating liquid is kept in a range of 170° C. to 190° C. The surface tension of the fabric is kept in a relatively loose condition as much as the knife interval of 2 mm so that the coating liquid can be coated satisfactorily. The reason is the same as the description of the first “S” coating.
<First “R” Coating>
The coating liquid of 62 g to 69 g is used per 1 yard with the width of 65 inches, and an interval of a coating knife from the surface of the fabric during coating is 1.5 mm. The room temperature of the drying room for drying the coating liquid is kept in a range of 165° C. to 180° C. The surface tension of the fabric is kept in a relatively loose condition as much as the knife interval of 1.5 mm so that the coating liquid can be coated satisfactorily.
<Second “R” Coating>
The coating liquid of 62 g to 69 g is used per 1 yard with the width of 65 inches, and an interval of a coating knife from the surface of the fabric during coating is 2 mm. The room temperature of the drying room for drying the coating liquid is kept in a range of 165° C. to 180° C. The surface tension of the fabric is kept in a relatively loose condition as much as the knife interval of 2 mm so that the coating liquid can be coated satisfactorily.
After the above process, mature the coating fabric in a natural condition for three or four days.
It is to prevent the curling of the fabric and the tunneling between the fabric and the backer again due to shrinkage of the fabric on the backer after the fabric and the backer are laminated together.
Since fabrics are different in quantity to absorb moisture, there occur the curling and tunneling when they come in contact with paper. Accordingly, when the fabric is matured in a natural condition during a sufficient period of time to thereby prevent the shrinkage of the product after the lamination of the product.
For lamination of fabric and backer and other processes, lamination is carried out by a comma coater.
As the backer, a white vellum sheet having a thickness of about 100 g, which is the most suitable for the environments required by the fabric used in this process and is similar to the surface fabric in speed to absorb and release moisture. Additionally, as time goes by, the fabric and the backer are all shrunk little by little, and hence, the white vellum sheet having the thickness of about 100 g is selected in order to keep a similar shrinking radial width.
As another method, as the backer, PET paper may be used, but it is preferable that the white vellum sheet having a thickness of about 100 g if possible. The backer of the vellum sheet is not even and flat in the surface, but it is advantageous in that the backer is easily separated from the surface fabric since the uneven surface gives air-permeability when the surface fabric is removed from the backer for use in a state where the uneven surface comes in close contact with the adhesive portion and the surface fabric.
The surface of the PET paper is more smooth and flat than the white vellum sheet of 100 g and even in the surface. However, since the PET paper is considerably low in air-permeability, it is difficult to easily separate it from the backer when the surface fabric is removed from the backer for use in a state where the PET paper comes in close contact with the adhesive portion and the surface fabric.
Basic ingredients of the removable adhesive are as follows.
INGREDIENTS
CAS NO
Weight (%)
Acrylic Polymer
—
31-35
Ethyl acetate
147-78-6
35-45
Toluene
108-88-3
10-20
Add a hardener of 2 g to compound solvent of 100 g to make total 102 g. This rate is the ideal rate to keep a strong adhesive force and to make the backer be easily removed.
Mix the compound solvent and the hardener for 30 minutes and coat the adhesive on the backer evenly. In this instance, the most preferred thickness of the adhesive for the surface fabric of the present invention is 1.8 micron to 2.0 micron.
After the lamination, since the polyester DTY absorbs the adhesive to a certain extent, if the thick coating is applied to the backer, the adhesive is evaporated and dried to a predetermined degree through a thermal drier, and then, the adhesive of the most suitable amount remains.
After the backer coated with the adhesive passes the drying room, the backer and the surface fabric are pressed together by a roller to thereby form a laminated sheet. In this instance, it is the most important to perform the laminating work in a state where the backer coated with the adhesive come in contact with the opposite face of the surface-coated face of the fabric, namely, the face to which the rear face gray coating was applied.
The reason is that the removable adhesive must be coated on the rear face of the surface-coated fabric, namely, the face to which the rear face gray coating was applied.
After the laminating work is completed, mature the product at the room temperature of about 50° C. for one day and carry out various cuttings (roll cutting, and re-cutting). Also, in this instance, roll the product in the opposite direction of a direction that the product is rolled previously, and then, start cutting after three or four hours. The reason is to keep smoothness of the finished product by re-rolling the fabric and the backer, which are rolled in one direction, in the opposite direction.
In brief, the adhesive fabric paper according to the present invention is made through the following steps.
Heat and cool rapidly the fabric woven with polyester DTYs, so that its width is reduced by 10% to 15%.
After that, coat the rear face of the fabric 1 with the coating liquid, which is made by mixing polyurethane resin and the white pigment in the ratio of 6:4, twice to thereby form a rear face white coating layer 11 .
Coat the rear face of the fabric 1 with the coating liquid, which is made by mixing polyurethane resin and the gray pigment in the ratio of 6:4, once to thereby form a rear face gray coating layer 12 .
Coat the fabric with the first “S” coating liquid containing ethylene vinyl acetate copolymer of 40˜50% by weight to thereby form a first “S” coating layer 21 .
Next, coat the fabric with the second “S” coating liquid containing polyurethane resin of 25% by weight to thereby form a second “S” coating layer 22 .
Furthermore, coat the fabric with the “R” coating liquid containing low molecular alcohol of 60˜75% by weight and silicon dioxide (silica) of 8˜12% by weight twice to thereby form an “R” coating layer 23 . After that, the backer 30 coated with the adhesive 31 is laminated on the rear face of the fabric.
While the present invention has been described with reference to the particular illustrative embodiment, it is not to be restricted by the embodiment but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiment without departing from the scope and spirit of the present invention.
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An adhesive fabric paper for printing is used to color printers for personal computers, printing machines for indoor and outdoor advertising, wide format printers, plotters to print colored images. The manufacturing method includes: heating and cooling a woven fabric; preparing a first “S” coating liquid, a second “S” coating liquid and an “R” coating liquid as coating liquids to be coated on the front face of the fabric and maturing them for three days; coating twice the rear face of the fabric; coating once the rear face of the fabric; carrying out first and second “S” coating works on the front face of the fabric with the first “S” coating liquid and the second “S” coating liquid; coating twice the front face of the fabric with the “R” coating liquid; and laminating a backer coated with an adhesive to the fabric.
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BACKGROUND OF THE INVENTION
[0001] This application claims priority to U.S. Provisional Application No. 60/511,898 filed Oct. 16, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates generally to brake friction pad assemblies such as are used in various automotive vehicle brake applications, including disc brake systems and drum brake systems. These systems may be utilized in automobiles, trucks, buses, off road equipment, airplanes, industrial machinery, etc. More particularly, it concerns an improved brake friction pad assembly structured to significantly reduce brake noise generated during brake system operation, and methods of making the improved brake friction pad assembly.
RELATED ART
[0003] Vibrations in a brake friction pad assembly generated during brake system operation frequently result in an audible squealing noise which may be objectionable and/or alarming to an operator, even though the noise may not result from any functionally problematic condition. In some situations, vibrations in a brake friction pad assembly may even contribute to premature or uneven wear of the abrasion surfaces. In any event, excessive brake vibration and noise is generally undesirable and many prior art techniques have been proposed for reducing or dampening vibrations in a brake friction pad assembly.
[0004] Notable examples of prior art attempts to reduce noise in a brake pad assembly include cutting sinusoidal grooves in the backing plate, as shown in U.S. Pat. No. 6,283,258 to Chen et al., and sculpturing of the friction-generating pad as shown in U.S. Pat. No. 5,456,339 to Zeng. These prior art techniques introduce undesirable side effects, however, such as increasing the time cycle of the fabrication process and/or adding cost to the brake/drum assembly.
[0005] One particularly effective method of attenuating brake noise without introducing these undesirable side effects consists of incorporating a shim onto the rear surface of the backing plate. The shim can be integrally molded from the flow of mix extruded through openings in the backing plate, as shown in U.S. Pat. No. 5,413,194 to Kulis, Jr. et al., hereby incorporated by reference in its entirety, or affixed in a subsequent operation. In the '194 Kulis, Jr. patent, the friction material mix or under-layer mix flows via an extrusion process into the openings in the backing plate, and in an alternative embodiment flows behind the backing plate to form an integral noise shim.
[0006] In the '194 Kulis, Jr. patent, the extrusion openings in the backing plate through which the friction material mix or under-layer mix flows are circular. The circular holes are utilized due to ease of manufacture through a punch process and the low cost of readily available round-shaped punch tools. In some braking applications, vibrations traversing the length of the backing plate are a source of objectionable brake noise generation, and the shim on the rear surface of the backing plate is not sufficient to satisfactorily attenuate the objectionable vibrations.
[0007] Accordingly, within a friction brake pad assembly having extrusion openings in the backing plate into which the friction material mix or under-layer mix are pressed during the forming operation, such as shown in the '194 Kulis, Jr. patent, there exists a need to provide additional noise attenuating properties without introducing features that increase the cost of the backing plate nor increase the time cycle of the fabrication process.
SUMMARY OF THE INVENTION
[0008] A brake friction pad assembly according to this invention comprises a rigid backing plate having a length and a thickness between opposed first and second faces. The backing plate is capable of transmitting vibrations along its length and width. The backing plate includes a primary extrusion opening extending between its opposed faces. A friction-generating pad element made from a molded material is pressed into contact with the first face of the backing plate such that the molded material fills the primary extrusion opening. The primary extrusion opening has a non-circular shape so that vibrations traveling the length of the backing plate are substantially dampened upon encountering the non-circular shape of said primary extrusion opening.
[0009] The invention also contemplates a method of dampening vibrations traveling through a brake friction pad assembly for a caliper-type vehicular disc brake system comprising the steps of: forming a rigid backing plate with a primary extrusion opening extending there through and at least two spaced mounting features on generally opposing sides of the primary extrusion opening; pressing a molded material onto a first face of the backing plate to form a friction-generating pad element and simultaneously filling the primary extrusion opening with the molded material; generating vibrations in the backing plate between the spaced mounting features; and forcing the vibrations to travel in a non-arcuate path as they find their way around the periphery of the primary extrusion opening to thereby dampen the vibrations within the friction pad assembly.
[0010] It has been discovered that in friction brake pad assembly having extrusion openings in the backing plate into which the friction material mix or an under-layer mix are pressed during the forming operation, vibrations traveling across the backing plate will be substantially dampened by forming the primary extrusion opening with a non-circular shape. It is hypothesized that this advantageous effect is realized by the introduction of reflecting surfaces caused by the non-circular peripheral edges of the primary extrusion opening. This is in contrast to the prior art circular openings which are believed to allow mechanical waves to flow too efficiently around their periphery as they travel across the length and/or width of the backing plate.
[0011] In alternative embodiments of the present invention, the number, configuration, and placement of the extrusion openings through the thickness of the backing plate are varied to alter the natural vibrational frequency and noise attenuating properties of the friction brake pad assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein:
[0013] FIG. 1 is a cut-away perspective view a brake pad assembly according to the subject invention in which the friction-generating pad element is fabricated from a first material mixture formulation, and the noise-damping pad element is fabricated from a second material mixture formulation;
[0014] FIG. 2 is a simplified cross-sectional view of a brake pad assembly in which the friction-generating pad element and the noise-damping pad element are fabricated from the same material mixture formulation;
[0015] FIG. 3 is a simplified cross-sectional view of a brake pad assembly which does not include a integrally molded noise-damping pad element;
[0016] FIG. 4 is a front elevation view of a brake pad assembly of the present invention wherein the primary extrusion opening is formed in the shape of an elongated slot and a secondary extrusion opening is formed in the shape of an elongated slot non-parallel to the orientation of the primary extrusion opening;
[0017] FIG. 5 is a front elevation view as in FIG. 4 wherein the primary extrusion opening and three secondary extrusion openings are formed in the shape of pairs of parallel elongated slots;
[0018] FIG. 6 is a front elevation view as in FIG. 5 wherein the primary extrusion opening and three secondary extrusion openings are formed in the shape of pairs of perpendicular elongated slots;
[0019] FIG. 7 is a front elevation view as in FIG. 4 wherein the primary extrusion opening is formed in the shape of a “T”, and a secondary extrusion opening is formed in the shape of a “T” mirrored in orientation to the primary extrusion opening; and
[0020] FIG. 8 is a front elevation view as in FIG. 4 wherein the primary extrusion opening is formed in the shape of an “H”, and a secondary extrusion opening is formed in the shape of an “H” mirrored in orientation to the primary extrusion opening.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a disc brake friction pad assembly according the subject invention is generally shown at 10 in FIG. 1 .
[0022] The assembly 10 includes a rigid backing plate 12 , which in the preferred embodiment is made from a steel material. The backing plate 10 has a length and a thickness between opposed first 14 and second 16 faces. The first face 14 is that surface of the backing plate 12 presented toward a rotor when operationally mounted in a vehicular caliper-type braking assembly. The first face 14 is generally planar and second face 16 is also generally planar and parallel to the first face 14 . The backing plate 12 further includes a top edge 18 and bottom edge 20 spaced from the top edge 18 . The top 18 and bottom 20 edges extend lengthwise of the backing plate 12 and form its upper and lower peripheral boundaries when operationally mounted in a vehicular caliper-type braking assembly. At least two spaced mounting features 22 are formed in the backing plate 12 for supporting the assembly 10 within a brake caliper system. In FIG. 1 , the mounting features are illustrated as simple profile features of the backing plate 12 , whereas in FIGS. 4-8 the mounting features 22 are shown as lug-shaped ears extending in opposite lengthwise directions from the backing plate 12 . Other mounting feature configurations are possible, as will be dictated by the brake system design.
[0023] The backing plate 12 also includes a primary extrusion opening, generally indicated at 24 , extending between its opposed first 14 and second 16 faces. The primary extrusion opening 24 is non-circular in shape, and may be skewed in its orientation relative to the top 18 and bottom 20 edges. The primary extrusion opening 24 is described in greater detail below.
[0024] A molded material, generally indicated at 26 , is pressed into contact with the first face 14 of the backing plate 12 such that the molded material 26 forms a friction-generating pad element 28 over the first face 14 while simultaneously filling the primary extrusion opening 24 . As shown in FIGS. 1 and 4 - 8 , the friction-generating pad element 28 can be formed in two or more distinct segments on the backing plate 12 , or in a single section as shown in FIGS. 2 and 3 . In the case of two or more segments, depending upon the magnitude of expected braking system noise-damping requirements, each pad segment may have different planar configurations, different planar areas, or different thicknesses. Thus, the friction-generating pad element 28 can include contour features 30 on its engagement surface to further tune the noise attenuating characteristics of the assembly 10 . Although not necessary, it is preferable that each such friction-generating pad segment 28 be associated with a different extrusion opening 24 in the backing plate 12 .
[0025] Preferably, although not necessarily, a noise-damping pad element 32 overlies and contacts a substantial portion of the second face 16 of said backing plate, as shown in FIG. 1 . The noise-damping pad element 32 is joined to the friction-generating pad element 28 by the molded material 26 contained within the primary extrusion opening 24 .
[0026] As shown in FIG. 1 , the friction-generating pad element 28 can be fabricated from a first material mixture formulation 34 , whereas the molded material 26 contained within the primary extrusion opening 24 and the noise-damping pad element 32 is fabricated from a common, generally homogenous second material mixture formulation 36 having more readily flowable extrusion properties than the first material mixture formulation 34 . Examples of suitable first 34 and second 36 material mixture formulations of the molded material 26 may be had by reference to the above-referenced U.S. Pat. No. 5,413,194 to Kulis, Jr. et al. Regardless of the material selected for the second material mixture formulation 36 , its properties should be chosen to provide the properties of a thermal insulator and/or vibration attenuation.
[0027] Although not shown in the Figures, one or more optional additional intermediate layers of molding material 26 can be introduced, each integrally joined with one another and to the backing plate 12 at the time of material molding. The intermediate layer will typically have either thermal resistive properties and/or noise attenuating properties.
[0028] As shown in FIG. 2 , the molded material 26 may comprise a common, generally homogenous material mixture formulation forming both the friction-generating pad element 28 and the noise-damping pad element 32 .
[0029] FIG. 3 illustrates another embodiment of the invention wherein the noise-damping pad element is not formed integrally with the friction-generating pad element 28 . In this situation, the noise-damping pad element can be formed separately and affixed in a subsequent operation, or omitted entirely depending upon the application and circumstances. The novel advantages of the present invention are realized in the embodiment of FIG. 3 by way of the primary extrusion opening 24 in the backing plate 12 by which vibrations traveling from one end of the backing plate 12 to the other will be substantially dampened as more fully described below.
[0030] Referring now to FIG. 4 , the backing plate 12 is shown including a secondary extrusion opening 38 adjacent the primary extrusion opening 24 . The secondary extrusion opening 38 is filled with the molded material 26 at the same time of filling the primary extrusion opening 24 . Preferably, the secondary extrusion opening 38 also has a non-circular shape, and in the case of FIG. 4 is formed in the shape of an elongated slot having an orientation on the backing plate 12 which is mirrored, or in this case generally perpendicular to, the orientation of the primary extrusion opening 24 . Although in this Figure the friction-generating pad element 28 is shown segmented with the primary 24 and secondary 38 extrusion openings associated with respective segments, it will be appreciated that this extrusion opening configuration could be equally effective with a non-segmented friction-generating pad element 28 .
[0031] FIG. 5 illustrates a slightly different configuration of the extrusion openings, wherein three secondary extrusion openings 38 are formed in the backing plate 12 , together with the primary extrusion opening 24 . In this example, one of the secondary extrusion openings 38 is arranged as a pair with the primary extrusion opening 24 in which they take the shape of parallel elongated slots associated with a respective segment of the friction-generation pad element 28 . The other two secondary extrusion openings 38 are themselves arranged as a parallel pair and associates with the other segment of the friction-generating pad element 28 .
[0032] FIGS. 7 and 8 illustrate yet additional shape configurations and orientations for the primary 24 and secondary 38 extrusion openings. For example, in FIG. 7 the primary extrusion opening 24 is formed in the general shape of a “T”, and the secondary extrusion opening 38 is also formed in the general shape of a “T”, but mirrored in orientation to the primary extrusion opening 24 . In FIG. 8 , the primary extrusion opening 24 is formed in the general shape of an “H”, and the secondary extrusion opening 38 is also formed in the general shape of an “H”, but mirrored in orientation to the primary extrusion opening 24 . These foregoing examples are merely suggestive of the shape configurations possible for the extrusion openings 24 , 38 . And, although in each example the secondary extrusion opening 38 is shown in a mirrored orientation relative to the primary extrusion opening 24 , such is not a necessary design relationship.
[0033] In all of these examples, however, the extrusion openings 24 , 38 are shown including at least one linear edge 40 which has been oriented substantially non-parallel to either of the top 18 and bottom 20 edges of the backing plate 12 . This feature is believed to enhance the noise-damping effects of the present invention. Specifically, vibrations traveling the length of the backing plate are substantially dampened upon encountering the non-circular shape of the extrusion openings 24 , 38 and are further attenuated by reflecting off the linear edge 40 .
[0034] Another beneficial feature common to the examples consists of the preferred absence of any sharp corners, both concave and convex, in the extrusion openings 24 , 38 . Referring again to FIGS. 4-8 , each extrusion opening 24 , 38 is shown including at least two concave corners 42 . The concave corners 42 are provided with radii of curvature; in the preferred embodiment the radii of curvature are at least as large as the thickness of the backing plate 12 however tighter radii can be used to beneficial effect as well. Similarly, FIGS. 7 and 8 reflect examples in which each extrusion opening 24 , 38 includes at least one convex corner 44 . The convex corner 44 also has a radius of curvature. These radii of curvature for corners 42 , 44 within the shape of the extrusion openings 24 , 38 function to both reduce stress concentrations within the backing plate and facilitate the formation technique of punching with a durable, low cost tool rather than EDM or laser cutting.
[0035] The friction brake pad assembly 10 having extrusion openings 24 , 38 in the backing plate 12 into which the molded material 24 are pressed during the forming operation has been found to substantially and beneficially alter the vibrations traveling from one end of the backing plate 12 to the other end. It is believed that these beneficial effects are achieved by forming the extrusion openings 24 , 38 with a non-circular shape. The non-circular shapes can be optimally configured to reduce a tendency for modal locking of the brake friction pad assembly 10 during use, without overstressing the structural integrity of the backing plate 12 . Different numbers, configurations, and placements of the extrusion openings 24 , 38 in the backing plate 12 have different noise attenuating benefits during brake applications. Preferably, the number, configuration, and placement of the extrusion openings 24 , 38 are selected and perfected to alter the natural vibrational frequency of the backing plate 12 , and thus reduce the tendency for modal locking of the brake components, which is likely a source of brake noise during vehicle brake usage. An additional benefit of the large surface area occupied by the extrusion openings 24 , 38 in the backing plate 12 is the increased amount of noise-damping material 26 present on the brake assembly 10 .
[0036] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, the novel features of the invention can be practiced in combination with one or more prior art style circular openings in the backing plate 12 . For example, as shown in FIG. 4 , the non-circular extrusion opening 24 can be paired with a circular opening 46 to achieve added benefit, and thereby take the form of a second extrusion opening. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. The invention is defined by the claims.
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A brake pad assembly ( 10 ) comprising a molded material ( 26 ) affixed to a backing plate ( 12 ) having opposed faces ( 14, 16 ), one or more non-circular extrusion openings ( 24, 38 ) through its thickness, and tab-like extensions ( 22 ) or other integral attachment for incorporating the assembly ( 10 ) by location and support into a vehicle brake system. The molded material ( 26 ) extends over both opposed faces ( 14, 16 ) of the backing plate ( 12 ) by being extruded through the extrusion openings ( 24, 38 ) to provide a unitary structure wherein molded material ( 26 ) at one side of the backing plate ( 12 ) functions as a friction-generating pad material ( 28 ) and the portion of the molded material ( 26 ) at the opposite side of the backing plate ( 12 ) functions as the assembly shim-like noise attenuating element ( 32 ) due to vibration damping properties. The number, configuration, and placement of the extrusion openings ( 24, 36 ) through the thickness of the backing plate ( 12 ) is varied to alter the noise attenuating properties of the assembly ( 10 ), further reducing the tendency for modal locking of brake components.
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SPECIFICATION
1. Field of the Invention
This invention is related to the field of stone cutting and of gemmology and particularly to the construction of a butterfly shape, and particularly with flapping wings.
2. Prior Art
Some patents have drawn our attention:
Des U.S. Pat. No. 340,669; Schachter; Oct. 26, 1993; shows a design of a precious stone. The general shape is octogonal.
Des. U.S. Pat. No. 324,003; Baranes; Feb. 18, 1992; shows a design for a gem. The general shape of the drown is trapezoidal: the long sides are angulated. The location of the angles of the body and of the crown do not permit the perceiving of a butterfly. If the top or bottom part were dug, one would alter the brilliance of the stone and one might not arrive at a butterfly. Furthermore the corners unveil positions of claws which are not diametrically opposed and which do not permit an equilibrated mounting.
U.S. Pat. No. 138,314 Bruhl, Apr. 29, 1873; utilizes an applique of precious stone superposed onto a base made of synthetic material. Multiple facets assure a brillance to the crown. No direction is given to the facets to create a special shape.
U.S. Pat. No. 2,447,407 Grain, Aug. 17, 1948; illustrate an internal opening to insert an intruder with some reflecting properties. There is an incision (20) in V having for goal to add to the reflection thanks to the sides of the incision; the method is not indicated to produce a precise shape like that of a butterfly, nor flapping wing shapes.
OBJECTIVES AND ADVANTAGES
There is a general objective of the invention to produce a stone almost alive in which one sees under examination flapping wings or other movement, without distorsion. A second objective is to provide a stone which has a trapezoidal crown, the sides having directional facets which allow the presence of a North-South reflectionless central location, so permitting the cutting of a location of separation between normal wings, as for a butterfly, without this separation causing a distorsion in the brilliancy, nor the appearance of an undesirable mark on the facets, which would depreciate the value and remove beauty from the stone.
A third objective is that the complete stone show itself as a butterfly.
A fourth objective is to let appear within the pavilion of the stone a simulation of the body of a butterfly and the normal separation and flapping of wings.
DRAWINGS
Presented herewith is an embodiment conform to the present invention, and with reference to the annexed drawing in which:
FIG. 1 is a perspective of a gem with butterfly appearance.
FIG. 2 is an upper view of the gem of FIG. 1.
FIG. 3 is a bottom view like FIG. 2.
FIG. 4 is a front view, according to line 4--4 of FIG. 6.
FIG. 5 is a side view, according to line 5--5 of FIG. 6.
FIG. 6 is a view of FIG. 2, in transparency, through the table of the stone.
FIG. 7 is a to view of a trapezoidal stone, before cutting, two cuts appearing in a dotted line.
DESCRIPTION OF THE INVENTION
In the following description and in the drawings which accompany it, the same chracterizing elements are identified by the same numbers. The preferred embodiment of the invention is illustrated in FIG. 1 where one sees a cut stone 20 in perspective, with at the top a table 24 and around a facet line 102.
FIG. 2 shows an external butterfly 22 delimited by the top view of the cut stone. One sees the table 24 of trapezoidal shape and reversed; in a corner one facet of lower claw 38', under a facet of upper claw 40', a facet of inferior side 42' under a facet of a superior side 44', a lower wing superior facet 52, a lower wing inferior facet 54, an inferior facet of top of wings 56, an upper wing superior facet 58, an upper wing separation cut 61, a wing side cut 64, a facet of first claw 49 and a facet of rest claw 51. One sees a left wing and a right wing 29 of the external butterfly.
FIG. 3 shows a bottom view of a superior claw 28, a second corner 30, a central corner 32, a median corner 33, a bottom corner 34, a superior pavilion corner 35, an inferior pavilion corner 37, an edge of upper support 39 and of lower support 41, and an edge of inferior claw 43.
FIG. 4 shows the wing side cut 64 in front view on the right, a corresponding wing side cut 64' on the left and a lower wing separation cut 62, as well as a face view of the inferior pavilion corner 37, an edge of lower support 41 and an edge of inferior claw 43. One also sees cutting edge facets which number eight 101, 102, 103, 104, 105, 106--FIG. 5--, 107, 108--FIG. 3--.
FIG. 5 shows the wing side cut 64, a pavilion angle 66, a cutting edge facet 106 and a break facet 45.
FIG. 6 shows, on a close look, the table 24 through which one sees an internal butterfly 74 with a interior right wing 26 and a left interior wing 27, a pavilion simulation 76 in X shape which serves as wing separation and as body shape for the two external butterflies 22 and internal 74.
The reversed right wing in relation to FIG. 3 comprises the facets of the superior claw 28', the second corner 30', the central corner 32', the median corner 33' and bottom the corner 34' and similarly for the left wing. The wing side cut 64--FIG. 2--is included to define the upper wings and the lower wings of the butterfly. The upper wing separation cut 61 and the lower wing separation cut 62 are needed to define the two parts of the stone, the left side and the right side of the external butterfly 22 with the external left wing 31, the external right wing 29. The lower wing separation cut 62 is located inside the limits of a non-reflective bottom zone 69 delimited by a dotted line--FIG. 7--at a location 96*.
One sees two side stars 46,46', an upper star 47, a lower star 50. One also sees corner edge facets 107, corresponding to the position at the extremity of the facet of superior claw 28' of FIG. 3 and 108 at the extremity of facet of edge of upper support 39, positionned respectively at the opposite of corner edge facets 105 and 104 of FIG. 4.
FIG. 7 shows a measuring index of the orientations of each of the facets, particuliarly those at the top. One uses an index of 96 locations, indicated 96*, around a circle of 360 degrees. At location 48* is found a upper wing separation cut 61 simulated by a dotted line and delimiting a non-reflection upper zone 68 and similarly at a location 96* where there will be a lower wing separation cut 62, references being:
48* location of a upper wing separation cut 61 and of
the upper wing superior facet 58 at +0° angle,
the inferior facet of wings top 56 at +9° angle, and
96* location of lower wing separation cut 62, and of
the lower wing inferior facet 54--FIG. 6--at +9° angle,
the lower wing superior facet 52 at +0° angle,
The positions of other elements are:
36* location of the facet of upper claw 40 to +7° angle, and of
the facet of lower claw 38, to the right, at +15° angle
60* location of facet of upper claw 40', at the left at a +7° angle
and of the facet of lower claw 38', at the left at a +15° angle
12* location of facet of first claw 49, at the right at +1° angle
and the facet of rest claw 51 at +9° angle;
84* location of facet of first claw 49', at the left, +1° angle
and of the facet of rest claw 51' at +9° angle;
19* location of facet of inferior side 42, at the right at +5° angle
77* location of superior side facet 44', at +5° angle.
Four (4) facets of girdle 50, 46, 47, 46' are at locations 96*, 19*, 48*, 77* at a 26° angle.
METHOD OF EXAMINATION OF A STONE
A stone is regarded in two optical ways: in the inside (FIG. 6) and on the outside (FIG. 2). The position of the top facets and of the bottom facets are above the other between the top and the bottom, are responsible for seeing a butterfly, at the top, on the outside and one in the inside of the stone.
The internal butterfly of the stone moves the wings if one oscillates the stone; the wing movement is caused by the reflexion of the light coming from the facets in various locations and angles of the pavilion (23) and of the crown (21). This phenomenon that I have witnessed may be verified by gemmologists or by a user who oscillates the stone. The preferred position of the location of the facets of the two butterflies, one in the outside and the other on the inside of the stone as well as the position of the angles of the facets, as described in FIG. 7, enable to keep the brilliance of the stone to its maximum while seeing one or two butterflies. A dark or opaque stone lets see only the external butterfly. The same butterfly-gem may be fabricated with locations and angles close to a preferred position by ±20%.
The position and angle of the facets, the number and the shape of the facets can change without distorting the butterflies, either because of an index of refraction typical to a particular kind of stone, either because of proportions, or by design or other reason. For example quartz has an index of refraction of 1.544 to 1.522 and topaz of 1.619 to 1.627. Then the critical angle of topaz will be of 42° for the pavilion and of 41° for the crown. For quartz it will be 43° for the pavilion and 42° for the crown. The degrees described for the butterfly gem--FIG. 7--will be added to the critical angle of the stone.
Facets position in butterfly position enables a reflexion of the light in opposite positions, which means the butterflies facets seen on the inside and on the outside, to the right and to the left, reflect the light everywhere, without affecting the stone brilliance. The two internal wings added to the visible external wings, give the apparence of a lepidopter.
While using materials (stone or other), this cut stone enables a maximum brilliance, which only facet stones are capable of giving: taking the interior light and the exterior of those stones, and making obvious the flare of the stone, while representing butterflies, without being sculpted stones, because the sculptured stones enhance the external color only.
As a gemmologic reference, an analysis of the girdle has demonstrated that the equilibrium of the girdle of the stone is excellent and very representative of a butterfly; the ratio length/width is of 1.38 and the shape is very attractive; the analysis of the brilliance shows a window of 5%, an extinction of 10% and a return of light of 85%; the analysis of the profile has demonstrated that the equilibrium of the profile of the stone is excellent in the two directions. The total depth is of 62%, the ratio crown/pavilion is 1:3, the convexity of the pavilion is null, the dimension of the table is of 60% and the girdle presents an ideal thickness, that is at least 1 mm for a 15 carat stone approximatively. The disposition of the facets and their symetry are excellent. At first sight, one is seduced by the vivacity and the brilliance observed. With some imagination, one may at times see the flapping of the wings of the butterfly, when one moves the stone and observes the facets of the pavilion.
For general use, the butterfly gem adapts itself to the production of calibrated stones of small and medium sizes. The choice of a gamut of color stones (amethyst, citrine, tourmaline, garnet, topaz and diamond . . . ) is indicated. The butterfly-gem is calibrated stones can serve for producing necklaces, pendentives, bracelets, brooches, etc. and add to the beauty, especially if one considers the originality of the design. The butterfly gem can be cut in an exclusive manner or not. More, the butterfly gem thus realized enables the stones to be free from setting problems. The position of the wings top permits the location of the claws on a butterfly gem, claws which are opposed one to the other, for more solidity, to permit an equilibrium of forces when the stone is mounted and avoid breakage by pressure of the claws against the stone.
The position of the top of the wings facets enables the location of the claws, and better the final shape of the butterfly while giving more amplitude and beauty to the butterfly, contrary to conventional geometrical shapes, where claws deform the stones.
The position and the angle of facets form a natural window at the center of the separation of wings of the top and bottom of the butterfly: the dug out thus formed does not diminish brilliance, by cutting down the reflection of light, so this stone will keep all its value and its beauty. The two diggings more or less deep of the separation of side wings of the butterfly are in a precise spot which does not affect the brilliance thanks to locations 19* and 77* of facets 42, 42' of the crown which reflect directly on facets 45 et 45' located on the opposite site of the pavilion.
In the preferred embodiment, the dimensions of the table permits enjoying the brilliance of the internal butterfly and to maintain the shape of a butterfly; preferably the trapeze will be of maximal width equal to 1.65 times the height. The angle of the sides of the trapeze correspond to the location 19* namely 19/96 of 360°. The surface of the trapeze of the table represents about 60% of the total surface of the stone, as seen from above.
The precise position of facets of the butterfly is such that when one regards the butterfly centrally, the two wings shine at the same time and the two triangles of the body of the butterfly reflect differently to thus form the body of the butterfly. The diagram position and degrees can be flexible up to 20% and keep nevertheless the same appearance of a butterfly.
SUMMARY OF THE INVENTION
The preferred diagram for the butterfly gem is the one described and represents a butterfly on the inside, or one on the outside, or both. But one can use other similar diagrams or equivalents in terms of results, depending on which tool, which stone, or other ways to made the butterfly gem.
To position the facets one uses a circle of reference--FIG. 7--on an index of 360°; divisible, for example, into 96 locations designated by * in which the two positions of the top and the bottom will be of 48* and of 96*. So if one looks at FIG. 3, one may position thus the successive facets of the right side, once reversed, as for FIG. 7, according to the table which follows, while identifying the number of the facet, followed by the location on the index and by the angle inscribed on the table and which adds to the critical angle of the stone, ex.: for quartz 43°.
______________________________________Facet No. Location Angle______________________________________24 96 45° with adaptator28 60 +0°28' 36 +0°30 72 -0, 5°30' 24 -0, 5°32 74 +0°32' 22 +0°33 80 +0, 5°33' 16 +0, 5°34 84 +0°34' 12 +0°35 48 +5°37 96 +5°38 36 +15°38' 60 +15°39 48 +26°40 36 +7°40' 60 +7°41 96 +26°42 19 +5°42' 77 +5°43 84 +16°43' 12 +16°44 19 +0°44' 77 +0°45 77 +19°45' 19 +19°46 19 +26°46' 77 +26°47 48 +26°49 12 +1°49' 84 +1°50 96 +26°51 12 +9°51' 84 +9°52 96 +0°54 96 +9°56 48 +9°58 48 +0°101 77 90°102 19 90°103 84 90°104 12 90°105 48 90°106 36 90°107 60 90°108 96 90°______________________________________
The facets of the butterfly gem may be increased in number or diminished, and the shape of the facets can change, while conserving the general shape of the butterfly. It is understood that when the term butterfly is used, it may represent any shape corresponding to the general shape of a butterfly.
It is understood that the mode of embodiment of the present invention which has been described herewith in reference to the annexed drawing, has been given as an indication and is non limitative and that modifications and adaptations may be brought about without departing from the object of the present invention. Other embodiments are possible and limited only by the scope of the following claims:
PARTS LIST
20. Cut stone
21. Crown
22. external butterfly
23. Pavilion
24. table
25. girdle
26. interior right wing
27. interior left wing
28. superior claw edge
29. right wing
30. second corner
32. central corner
33. median corner
34. bottom corner
35. superior pavilion corner
37. inferior pavilion corner
38. facet of lower claw
39. edge of upper support
40. facet of upper claw
41. edge of lower support
42. facet of inferior side
43. edge of inferior claw
44. facet of superior side
45. break facet
46. side star
47. upper star
49. facet of first claw
50. lower star
51. facet of rest claw
52. lower wing superior facet
54. lower wing inferior facet
56. upper wing inferior facet
58. upper wing superior facet
61. upper wing separation cut
62. lower wing separation cut
64. wing side cut
66. pavilion angle
68. non reflection upper zone
69. non reflective bottom zone
74. internal butterfly
76. pavilion simulation
101, 2, 3, 4, 5, 6, 7, 8 facets of girdle
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A cut stone having a crown (21) and a pavilion (23), the crown having peripherically four indents orientated face to face and forming a cross, the apparence of the crown of the stone forming a butterfly. The crown defines centrally a table in the shape of a reversed trapeze surrounded by facets defining two wings located toward the outside of the trapeze. The pavilion (23) comprises a number of facets distributed according to orientation angles combined to create a void of brilliance in the area of the indents. Under the table of the crown appears the reflection of the pavilion which uncovers two flapping wings located internally; the flapping wings added to the two wings at the exterior of the trapeze, give the appearance of a lepidopter.
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CROSS REFERENCE TO RELATED PATENTS AND APPLICATIONS
The following applications, the disclosures of each being totally incorporated herein by reference are mentioned:
U.S. Provisional Application Ser. No. 60/631,651, filed Nov. 30, 2004, entitled “TIGHTLY INTEGRATED PARALLEL PRINTING ARCHITECTURE MAKING USE OF COMBINED COLOR AND MONOCHROME ENGINES,” by David G. Anderson, et al.;
U.S. Provisional Patent Application Ser. No. 60/631,918, filed Nov. 30, 2004, entitled “PRINTING SYSTEM WITH MULTIPLE OPERATIONS FOR FINAL APPEARANCE AND PERMANENCE,” by David G. Anderson et al.;
U.S. Provisional Patent Application Ser. No. 60/631,921, filed Nov. 30, 2004, entitled “PRINTING SYSTEM WITH MULTIPLE OPERATIONS FOR FINAL APPEARANCE AND PERMANENCE,” by David G. Anderson et al.;
U.S. application Ser. No. 10/761,522, filed Jan. 21, 2004, entitled “HIGH RATE PRINT MERGING AND FINISHING SYSTEM FOR PARALLEL PRINTING,” by Barry P. Mandel, et al.;
U.S. application Ser. No. 10/785,211, filed Feb. 24, 2004, entitled “UNIVERSAL FLEXIBLE PLURAL PRINTER TO PLURAL FINISHER SHEET INTEGRATION SYSTEM,” by Robert M. Lofthus, et al.;
U.S. application Ser. No. 10/860,195, filed Aug. 23, 2004, entitled “UNIVERSAL FLEXIBLE PLURAL PRINTER TO PLURAL FINISHER SHEET INTEGRATION SYSTEM,” by Robert M. Lofthus, et al.;
U.S. application Ser. No. 10/881,619, filed Jun. 30, 2004, entitled “FLEXIBLE PAPER PATH USING MULTIDIRECTIONAL PATH MODULES,” by Daniel G. Bobrow.;
U.S. application Ser. No. 10/917,676, filed Aug. 13, 2004, entitled “MULTIPLE OBJECT SOURCES CONTROLLED AND/OR SELECTED BASED ON A COMMON SENSOR,” by Robert M. Lofthus, et al.;
U.S. application Ser. No. 10/917,768, filed Aug. 13, 2004, entitled “PARALLEL PRINTING ARCHITECTURE CONSISTING OF CONTAINERIZED IMAGE MARKING ENGINES AND MEDIA FEEDER MODULES,” by Robert M. Lofthus, et al.;
U.S. application Ser. No. 10/924,106, filed Aug. 23, 2004, entitled “PRINTING SYSTEM WITH HORIZONTAL HIGHWAY AND SINGLE PASS DUPLEX,” by Lofthus, et al.;
U.S. application Ser. No. 10/924,113, filed Aug. 23, 2004, entitled “PRINTING SYSTEM WITH INVERTER DISPOSED FOR MEDIA VELOCITY BUFFERING AND REGISTRATION,” by Joannes N. M. dejong, et al.;
U.S. application Ser. No. 10/924,458, filed Aug. 23, 2004, entitled “PRINT SEQUENCE SCHEDULING FOR RELIABILITY,” by Robert M. Lofthus, et al.;
U.S. patent application Ser. No. 10/924,459, filed Aug. 23, 2004, entitled “PARALLEL PRINTING ARCHITECTURE USING IMAGE MARKING DEVICE MODULES,” by Barry P. Mandel, et al;
U.S. patent application Ser. No. 10/933,556, filed Sep. 3, 2004, entitled “SUBSTRATE INVERTER SYSTEMS AND METHODS,” by Stan A. Spencer, et al.;
U.S. patent application Ser. No. 10/953,953, filed Sep. 29, 2004, entitled “CUSTOMIZED SET POINT CONTROL FOR OUTPUT STABILITY IN A TIPP ARCHITECTURE,” by Charles A. Radulski et al.;
U.S. application Ser. No. 10/999,326, filed Nov. 30, 2004, entitled “SEMI-AUTOMATIC IMAGE QUALITY ADJUSTMENT FOR MULTIPLE MARKING ENGINE SYSTEMS,” by Robert E. Grace, et al.;
U.S. patent application Ser. No. 10/999,450, filed Nov. 30, 2004, entitled “ADDRESSABLE FUSING FOR AN INTEGRATED PRINTING SYSTEM,” by Robert M. Lofthus, et al.;
U.S. patent application Ser. No. 11/000,158, filed Nov. 30, 2004, entitled “GLOSSING SYSTEM FOR USE IN A TIPP ARCHITECTURE,” by Bryan J. Roof;
U.S. patent application Ser. No. 11/000,168, filed Nov. 30, 2004, entitled “ADDRESSABLE FUSING AND HEATING METHODS AND APPARATUS,” by David K. Biegelsen, et al.;
U.S. patent application Ser. No. 11/000,258, filed Nov. 30, 2004, entitled “GLOSSING SYSTEM FOR USE IN A TIPP ARCHITECTURE,” by Bryan J. Roof;
U.S. application Ser. No. 11/001,890, filed Dec. 2, 2004, entitled “HIGH RATE PRINT MERGING AND FINISHING SYSTEM FOR PARALLEL PRINTING,” by Robert M. Lofthus, et al.;
U.S. application Ser. No. 11/002,528, filed Dec. 2, 2004, entitled “HIGH RATE PRINT MERGING AND FINISHING SYSTEM FOR PARALLEL PRINTING,” by Robert M. Lofthus, et al.;
BACKGROUND
The described exemplary embodiments generally relate to maintaining image registration in image processing. More particularly, the description relates to systems and methods in which image registration errors in output images are reduced in image processing systems that include tandem print engines. The tandem print engines, for example, can process single pass duplexing and/or multi-pass duplexing.
Electrophotography, a method of copying or printing documents, is performed by exposing a light image representation of a desired original image onto a substantially uniformly charged photoreceptor substrate, such as a photoreceptor belt. In response to this light image, the photoreceptor discharges to create an electrostatic latent image of the desired original image on the photoreceptor's surface. Developing material, or toner, is then deposited onto the latent image to form a developed image. The developed image is then transferred to an image receiving substrate. The surface of the photoreceptor is then cleaned to remove residual developing material and the surface as recharged by a charging device in preparation for the production of the next image.
Color images can be produced by repeating the above-described recording process once for each differently-colored toner that is used to make a composite color image. For example, in a one-color imaging process, referred to herein as the Recharge, Expose, and Develop, Image (REaD IOI) process, a charged photoreceptor surface is exposed to a light image that represents a first color. The resulting electrostatic latent image is then developed with a first colored toner. The toner is typically of a subtractive primary color, including magenta, yellow, cyan, or black. The charge, expose and develop process is repeated for a second colored toner, then for a third colored toner, and finally for a fourth colored toner. The four differently-colored toners are placed in superimposed registration on the photoreceptor so that a desired composite color image results. That composite color image is then transferred and fused onto an image receiving substrate.
Tandem print engine systems include two print engines arranged in a series configuration. Each print engine includes a photoreceptor belt and imagers disposed at spaced positions along the length, i.e., the process direction, of the photoreceptor belt. Each imager comprises an image source that exposes the photoreceptor belt. Typically, the image source includes a light emitting device that emits a light beam that is moved laterally across the photoreceptor belt to expose the photoreceptor belt to create a latent electrostatic image on the photoreceptor belt. Each latent image is then developed as outlined above. Image receiving substrates, such as sheets of copy paper, are fed in a time-controlled manner to the print engines. The first print engine transfers its developed image to the simplex side of the image receiving substrate. The image receiving substrate is then inverted and presented to the second print engine. The second print engine then transfers its developed image to the duplex side of the image receiving substrate.
Each photoreceptor belt of the first and second print engines includes a seam where opposed end portions of the photoreceptor belt are joined together. The photoreceptor belts include pitch regions in which images can be satisfactorily formed. Images cannot be satisfactorily formed at the seams, because the images formed at seams are normally defective. Accordingly, it is important to control the locations of the seams of both of the first and second photoreceptor belts during print runs, to prevent forming images at the seams, and to ensure that images are formed only in the pitch regions. A consistent and predictable placement of the photoreceptor belts, with respect to each other, is desirable in order to simplify an intermediate or inverter paper path between two print engines.
In a tandem print engine configuration, there are several technology issues involved with synchronizing two photoreceptor belt modules of two separate print engines in a manner that does not negatively impact the registration of either module. If the periods of revolution of the two photoreceptor belts are not matched, then the positions of the seams will also not be synchronized. The photoreceptor belts can have different lengths and, accordingly, in such configurations must rotate at different velocities (speeds) to maintain the same periods of revolution. If the periods of revolution are not synchronized appropriately to each other or with imager velocities, image to paper registration errors will occur during printing. The image to paper registration errors can be characterized as 1) simplex to duplex image registration errors if the photoreceptor and imager velocities for each print engine are not matched appropriately, or 2) image-on-image (IOI) registration errors from changes in the photoreceptor velocity or imager velocity while printing is occurring. Image-on-image registration errors occur during the building of color images on the photoreceptor belts. If, during stacking the multiple color separation layers of a color image on each other, the images are not aligned with each other, then image registration errors between the color separation layers will occur. These registration errors produce print defects such as color shifts and trapping errors.
Registration errors are caused generally by the motion quality of the photoreceptor belts and the manner that the imagers form the latent images on the photoreceptor belts. Regarding the motion quality of the photoreceptor belts, image registration errors can be caused by changes in the photoreceptor belt velocity, making it difficult to form images smoothly and to align lead edges of the images on the photoreceptor belt. Velocity changes can occur due to various different factors, including errors of the drive motor, errors in roller velocities and diameters, belt length changes during operation due to tension and thermal effects, and normal roller and belt tolerances.
Factors that can cause registration errors in the manner in which the imagers form the latent images, include errors in the lateral scan velocity, i.e., the exposure velocity, of the image sources across the photoreceptor belt, the scanning start and end points of the scanning light beam, and the length of the scan lines.
In simplex (single print engine) configurations, the image registration can be set up off-line. Thus, adjustments can be made at times when print runs are not being performed. In such configurations, the photoreceptor belt velocity is maintained as constant as possible to minimize registration errors. In addition, the imagers are set to a specific reference and their velocity is tightly maintained. If, during the course of producing an image, the velocity of the photoreceptor belt and the scan velocity of the image sources of the imager vary with respect to each other, either in position or velocity, then registration errors will occur.
Simplex print engine systems can include monitoring systems for measuring and compensating for image registration errors. Simplex print engine systems can calibrate themselves to the characteristics of the photoreceptor belt to achieve good image alignment for color images. If the photoreceptor belt runs either too fast or too slow, the scan velocity of the image sources can be automatically adjusted to counter the change in the photoreceptor belt velocity. As long as the photoreceptor belt velocity is maintained substantially constant, then only small image registration errors occur due to the self-correcting measures that are taken by the system.
For tandem print engine configurations, however, the synchronization requirements for the two print engines require that the photoreceptor belt velocity of the downstream print engine, i.e., the “slave print engine,” must be adjusted to keep it timed with the period of revolution of the photoreceptor belt of the upstream print engine, i.e., the “master print engine,” Otherwise, it is not possible to control the locations of the seams of the photoreceptor belts of the master and slave print engines. As explained, it is important to control the seams to prevent the formation of images on the seams.
In tandem print engine configurations, various factors can cause the two photoreceptor belts to be out of synchronization with each other. Namely, the photoreceptor belt velocities and lengths can change over time due to changes in the roller diameters, encoder diameters and thermal effects. The belt length can be out of specification originally and can also vary during operation due to stretch caused by tension and thermal effects. The encoder roller that measures the belt velocity can change in diameter due to thermal effects. Consequently, the photoreceptor belts can run at different periods of revolution. In addition, errors can occur between the scan velocities of the image sources of the imagers of the different print engines. However, as outlined above, the scan velocities of the imagers also need to be coordinated with the velocity of the associated photoreceptor belt to maintain proper overall image quality.
In order to synchronize the photoreceptor belts of the master and slave print engines, the photoreceptor belt velocity of the slave print engine can be changed. In making such adjustments for the slave print engine, the slave print engine should be adjusted on-line. Otherwise, the productivity of the tandem print engine is decreased.
One possible approach to making such velocity adjustments while the slave print engine is on-line includes making the velocity adjustments for the slave print engine sufficiently small that the adjustments would produce registration errors so small that they would be almost imperceptible. This approach, however, requires stringent adjustment resolution or quantization levels in the photoreceptor belt and in imager controllers of the slave print engine, because both subsystems will need to be adjusted when the photoreceptor belt velocity is adjusted. The cost implications of such fine adjustment capability are high.
A high level of resolution is presently achievable for the slave print engine photoreceptor belt module. Velocity resolutions down to about 1/64 Hz (or 0.00082%) can currently be achieved. Such small changes are expected to be imperceptible. Thus, the photoreceptor belt velocity of the slave print engine could be adjusted slowly at a sufficiently small step size without undue registration errors occurring.
It is not, however, presently possible to satisfactorily reduce the image registration errors by making such small step size adjustments of the photoreceptor belt velocity for the slave print engine. That is, in tandem print engines, the ratio of the velocity of the photoreceptor belt and the velocity of the imagers, for example the scan velocity, or exposure velocity, of image sources, defines the absolute magnification of the final image that is formed on the photoreceptor belt. Accordingly, if the photoreceptor belt velocity is changed, then the imager velocity must also be changed to maintain the desired ratio, or else the length of the image in the process, or slow scan, direction will change. Consequently, the imager velocity must be adjusted to maintain the desired absolute magnification, to maintain the ratio of the photoreceptor belt velocity to the imager velocity.
Imager controllers can have, for example, 32, 64, 128 or 256 discrete levels of imager scan velocity adjustment for the light emitting devices. With 256 steps over the adjustment range that is desirable for imagers, which is typically about 1.6%, the adjustment resolution is about 0.0125% per step. This adjustment resolution is very coarse, and is about fifteen times greater, compared to present adjustment capabilities of photoreceptor belt controllers. This adjustment resolution would cause significant image registration errors if changes were made to the imager velocity during a print run. However, improving upon this adjustment resolution of the imagers is not a satisfactory solution to this problem, because, as the number of adjustment level increases, the more difficult the adjustment implementation becomes and the more expensive the adjustment system generally becomes.
Adjusting the velocities of the imagers at the coarse adjustment capabilities of the imager controller is also unsatisfactory. That is, in order to avoid large registration errors, it would be necessary to make changes to the imager velocity only at times when print runs are not being performed, i.e., when the slave print engine is off-line. This approach would require that the slave print engine be taken off-line periodically and skipping one revolution of the photoreceptor belt to adjust the imager velocity. This approach would create a decrease in the tandem print engine productivity, as the master print engine would also have to go off-line at the same time. In addition, this approach would also add additional complexity to the machine communications and scheduling algorithm needed for tandem print engine configurations. Accordingly, making adjustments to the imager velocity off-line would also be unsatisfactory.
One possible approach to making such velocity adjustments while the slave print engine is on-line includes matching the periods of revolution of the photoreceptors of the master and slave print engines during print runs, by simultaneously adjusting both the velocity of the slave photoreceptor and imagers of the slave engine. The velocity controllers for the slave photoreceptor and imagers can have the same dynamic response and can be simultaneously actuated, to minimize incremental registration errors in the slave print engine. Cross reference is made to commonly assigned U.S. Pat. No. 6,219,516, the disclosure of which being totally incorporated herein by reference.
As discussed in greater detail below, changes in the ratio between the velocities of the photoreceptor belt and the imagers in a print engine cause image to paper registration errors in the print engine. A phase difference between the master print engine and the slave print engine due to an intermediate inverter also causes registration errors. The phase difference represents a transit time for the substrate to travel through the inverter.
The velocity adjustments can thus be made at an adjustment level that can be achieved by the controllers of both the photoreceptor and the imagers. Thus, even in systems in which the adjustment resolution capabilities of the two subsystems vary significantly, the adjustments to both systems can be made at an adjustment level that is achievable by both systems.
Because it is not necessary to take the slave print engine off-line periodically to make such adjustments, the systems and methods hereinafter described can improve productivity in tandem print engine configurations. The systems and methods described avoid the need to introduce additionally complex machine communications and scheduling techniques that would be needed to be able to make adjustments off-line in tandem print engine configurations. The exemplary embodiments also avoid the need for an intermediate buffer tray to hold substrates while they move from the master print engine to the slave print engine.
BRIEF DESCRIPTION
One exemplary embodiment of an image processing system that forms an image on an image receiving substrate comprises a first print engine and a second print engine downstream from the first print engine. The second print engine is slaved to the first print engine. The first print engine comprises a first photoreceptor having a first period of revolution. The second print engine comprises a second photoreceptor having a second period of revolution. The image processing apparatus further comprises an intermediate inverter that inverts the image receiving substrate between the first print engine and the second print engine, wherein the first print engine prints on a simplex side of the image receiving substrate and the second print engine prints on a duplex side of the image receiving substrate. The inverter determines a phase difference between a first seam signal from the first photoreceptor and a second seam signal from the second photoreceptor.
Another exemplary embodiment of an image processing apparatus with tandem print engines for forming an image on an image receiving substrate comprises a first print engine including a first photoreceptor having a first photoreceptor belt with a first period of revolution. The apparatus further includes a second print engine downstream from the first print engine, the second print engine including a second photoreceptor having a second photoreceptor belt with a second period of revolution. The apparatus further comprises an inverter between the first print engine and the second print engine. The inverter has a constant time period for inverting a substrate from the first print engine to the second print engine. A tandem print controller determines the equivalent position difference at start up between a first seam in the first photoreceptor belt and a second seam in the second photoreceptor belt wherein said equivalent position difference substantially equal to the time period for inverting.
Still another exemplary embodiment includes an image processing method for forming an image on an image receiving substrate using an image processing apparatus comprising a first print engine having a first photoreceptor belt with a first period of revolution, and a second print engine arranged in tandem with the first print engine, the second print engine having a second photoreceptor belt with a second period of revolution. The apparatus further includes an inverter between the first and the second print engine. The method includes measuring an inverter period. The inverter period substantially matches a transit time of a substrate between the first print engine and the second print engine. The method further includes parking the second print engine such that a seam in the second photoreceptor belt is offset by the inverter period relative to a seam in the first photoreceptor belt. Additionally, the first period of revolution of the first photoreceptor belt and the second period of revolution of the second photoreceptor belt are measured. A gain factor is then calculated by determining a ratio between the first period of revolution and the second period of revolution.
Yet another exemplary embodiment includes an image processing method for forming an image on an image receiving substrate using an image processing apparatus comprising a first print engine including a first photoreceptor belt having a first period of revolution, and a second print engine arranged in tandem with the first print engine and including a second photoreceptor belt having a second period of revolution. A plurality of imagers form an image on the second photoreceptor belt. The method includes offsetting a seam in the second photoreceptor belt by a period substantially equal to a transit time for a substrate to travel through an inverter between the first print engine and the second print engine. The first period of revolution of the first photoreceptor belt is maintained substantially equal to the second period of revolution of the second photoreceptor belt during a print run. A substantially constant ratio is maintained between the velocity of the second photoreceptor belt and an exposure velocity of the plurality of imagers during the print run. The method further includes printing a first image on the image receiving substrate at the first print engine, and printing a second image on the image receiving substrate at the second print engine.
DRAWING DESCRIPTIONS
FIG. 1 schematically illustrates a tandem print engine system;
FIG. 2 shows one exemplary embodiment of an image processing apparatus that incorporates the image registration control system;
FIG. 3 is a flowchart outlining one exemplary embodiment of a control method;
FIG. 4 schematically illustrates a tandem print engine and a constant delay inverter; and,
FIG. 5 schematically illustrates a phase relationship between first and second print engines in the tandem print system.
DETAILED DESCRIPTION
The apparatus and method to be described in more detail hereinafter includes a machine configuration where two (or more) standard print engines or image output terminals (IOTs) will be placed in series to provide single pass duplex prints. The first IOT can print the simplex side, the paper can then move through an intermediate transport where it is inverted and presented to the second IOT where the duplex side can be printed. One issue involved with appending two print engines is the synchronization of the seams of both photoreceptor (P/R) belts such that the seam on the second P/R module never ends up in the image area. A consistent and predictable placement of the P/R belts with respect to each other also allows the intermediate paper path to become much simpler. If synchronized properly, there will be no need of an intermediate buffer tray to hold prints while they move from the master print engine to the slave print engine and scheduling of the images becomes very predictable.
One exemplary embodiment of an image processing apparatus incorporating image registration control systems in accordance with the exemplary embodiments is described below. An image data source and an input device can be connected to the image processing apparatus over links. The image data source can be a digital camera, a scanner, or a locally or remotely located computer, or any other known or later developed device that is capable of generating electronic image data. Similarly, the image data source can be any suitable device that stores and/or transmits electronic image data, such as a client or a server of a network. The image data source can be integrated with the image processing apparatus, as in a digital copier having an integrated scanner, or the image data source can be connected to the image processing apparatus over a connection device, such as a modem, a local area network, a wide area network, an intranet, the Internet, any other distributed processing network, or any other known or later developed connection device.
It should also be appreciated that, while the electronic image data can be generated at the time of printing an image from electronic image data, the electronic image data can be generated at any time prior to the printing. Moreover, the electronic image data need not be generated from an original physical document, but can optionally be created from scratch electronically. The image data source thus can be any known or later developed device that is capable of supplying electronic image data over the link to the image processing apparatus. The link can thus be any known or later developed system or device for transmitting the electronic image data from the image data source to the image processing apparatus.
The input device can be any known or later developed device for providing control information from a user to the image processing apparatus. Thus, the input device can be a control panel of the image processing apparatus, or can be a control program executing on a locally or remotely located general purpose computer, or the like. The link(s) can be any known or later developed device for transmitting control signals and data input using the input device from the input device to the image processing apparatus.
As shown in FIGS. 1 and 2 , in one exemplary embodiment, the image processing apparatus 200 includes a tandem controller 210 , a print engine scheduler 220 , a master print engine or module 300 , and a slave print engine or module 400 . The master print engine can include a master photoreceptor (P/R) module 310 and a master paper registration system 320 . The slave print engine 400 can include a slave raster output scanner (ROS) control module 410 , a slave P/R module 420 , and a slave paper registration system 430 .
As best shown in FIG. 1 , the tandem print engine includes the master print engine 300 and the slave print engine 400 arranged in a series configuration. During a print run of the image processing apparatus 200 , a feeder 600 feeds an image receiving substrate, such as copy paper, to the master print engine 300 . The image receiving substrate has a simplex side and a duplex side. The master print engine 300 prints an image on the simplex side of the image receiving substrate. The image receiving substrate is then inverted by an inverter transport device 700 , disposed between the master print engine 300 and the slave print engine 400 , and transported to the slave print engine 400 . The slave print engine 400 can print another image on the duplex side of the image receiving substrate. The image receiving substrate is then transported to a finisher device 800 . The master print engine 300 includes a P/R that comprises a master P/R belt 350 and the slave print engine 400 includes a P/R that comprises a slave P/R belt 450 . As shown in FIGS. 1 and 5 , the master P/R belt 350 has a seam 355 and the slave P/R belt 450 has a seam 455 .
One component of the image processing apparatus 200 is the tandem controller 210 and the algorithms which are programmed into this controller 210 . To be described in more detail hereinafter, the tandem controller 210 can determine the desired phase delay between the two print engines 300 , 400 , synchronize the print engines, and maintain that synchronization in the presence of thermal and other disturbances.
One module is determined to be the master or first print engine 300 and another module is determined to be the slave or second print engine 400 . The master P/R belt 350 and the slave P/R belt 450 each rotate at a selected period of revolution, i.e., the amount of time for the belt to make one complete revolution. The tandem controller 210 adjusts the velocity of the slave P/R belt 450 and the velocity of the imagers of the slave print engine 400 , if the sensors associated with the master P/R belt 350 and the slave P/R belt 450 , indicate that the periods of revolution of the master and slave P/R belts 350 , 450 are not properly matched. As the master's period of revolution changes, the slave will be required to follow. The tandem controller determines the appropriate corrections to be made to both the P/R module and motor and polygon assembly (MPA) velocities for the slave print engine 300 to keep the two modules synchronized without impacting an 101 (image-on-image) registration on either print engine. The MPA comprises a servo system which regulates the polygon speed. Only the inputs and outputs of the portion of the tandem print engine system that are under the influence of the tandem controller are shown in FIG. 2 .
The tandem controller 210 can compare the periods of each P/R belt 350 , 450 as it travels around the respective P/R module 300 , 400 and calculate a gain factor based on the ratio of these two periods.
gain_Factor
=
slave_Period
master_Period
This gain factor is then applied to the current slave P/R and ROS MPA velocities to correct for the difference in the period. The change is a relative change based on the master P/R module's velocity. The slave P/R velocity is changed to ensure the two P/R belt seams are fixed in relation to one another. Once the slave P/R belt speed is changed, the ROS MPA speeds must be changed as well so that the process direction magnification of the prints remains constant. Corrections can be made to both the P/R belt velocity and the ROS MPA velocities simultaneously.
The corrections are made in a relative sense rather than as an absolute velocity change. The changes relative to the master P/R module's velocity is sufficient because the absolute belt speed tolerances on a single P/R module are acceptable. The corrections simply ensure that the two P/R belt revolution periods are identical, but it is to be appreciated that the individual belt velocities may vary slightly from the nominal.
Referring now to FIG. 3 , a flowchart is therein displayed showing how the tandem control system 210 can be operated. The tandem print engine control system can be outlined in the following operational modes: a set-up mode 230 , a print mode 250 , a run/maintenance mode 270 , and a stop mode 290 .
The tandem set-up mode 230 will move the two independent print engines from unknown P/R module seam phase orientations and place them in relationship to each other in such a way that the start-up transients and registration effects are minimized at the beginning of the print run. The phase difference (in time) between two belt seam signals (or seam hole signals) must first be determined. The two seam signals comprise a first seam signal from the master P/R module and a second seam signal from the slave P/R module. This will provide the proper synchronization phase difference or orientation between the two P/R belt modules that can then be maintained by the tandem controller. One component that enables the tandem controller to be effective is the inverter 700 shown in FIG. 4 . The inverter 700 can maintain a phase difference between the two signals as different length papers are fed into the image processing apparatus 200 . It is to be appreciated that a constant phase difference or constant delay can be easily maintained when the same sized paper is fed into the image processing apparatus 200 . An intermediate inverter paper path with a constant delay, regardless of paper size, can reduce the set-up time between feeding various sizes of paper, or to enable variable size paper to be run through the apparatus 200 .
If the time through an inverter path 710 is not known, it must be measured to determine the proper phase relationship of the two seam holes of the master and slave P/R module 300 , 400 . To measure inverter time, paper can be passed through the system. The average time from a paper registered signal on the master P/R module to a paper registered signal on the slave P/R module 400 is recorded. At this stage, imaging is not being performed, only the paper inverter time or transit time is being measured. The paper is not registered actively and no corrections are made during this test. The measurement of inverter time is represented and shown as T inverter . The desired phase difference between the first and second seam hole signals can then be calculated as follows:
T phase =T inverter mod T period1 [mod=modulus]
given the fact that when synchronized
T period1 =T period2
The aforementioned will result in a time period that is less than one belt period and represents the proper phase delay (in time) between the two seam hole signals. In addition, X phase can be calculated and represents the equivalent position difference along the P/R belt travel in the two seam holes as shown in FIG. 5 and as detailed below:
X phase =T phase ·V mod2 ·
The belt modules can now be run independently and the periods of their rotation measured along with an average period for both the master and slave P/R modules. The desired slave P/R velocity can be calculated by the following equation or control law:
V
slave
=
V
slave
·
(
1
+
(
T
periodSlave
-
T
periodMaster
)
T
periodMaster
)
.
At the completion of the period measurement, the P/R modules 300 , 400 can each be parked in such a way that they are in the right phase orientation for running. Once parked the desired or new velocity can be downloaded to the slave P/R module. A new slave MPA clock is calculated based on the same gain factor as used in the change in slave velocity and downloaded. If the reference phase delay between the seam hole signals was just learned, then the system can be started up and several sheets fed to make sure that the paper path can properly register the paper at the slave module 400 . Average paper registration correction during printing may be used to fine tune the phase reference determined above. This function requires communication from the paper registration system. The set-up mode 230 is now complete.
The print mode 250 of operation will now be described. The effect of such mode of operation is to get the two P/R modules 300 , 400 sufficiently synchronized that the paper registration system can adjust the paper to image registration sufficiently. The print mode 250 of operation is also responsible for keeping the two P/R modules synchronized in the presence of thermal disturbances, P/R belt stretch, and measurement errors, etc. Corrections can be made to the slave print engine to make it follow the master print engine. All corrections performed on-line (i.e. while making prints) must be done in such a way as to minimize their registration effects. Once the set-up routine has been run and the modules are synched together the system is ready to make prints.
Printing initiates by issuing simultaneous start commands to both the master and slave P/R modules. It is to be appreciated that the closer to starting at the same time the better the start up transient will be. The phase relationship of the two seam holes can be checked for acceptability. Acceptability is determined by conformance within a certain phase target in mm or sec. One example is a phase target of about ±4 mm. The tandem controller can then issue a signal that the P/R modules are synched and ready for printing.
The tandem controller then transitions to a maintenance mode 270 . The maintenance mode ensures that the two P/R modules maintain synchronism such that the paper registration system can adjust the paper to image registration sufficiently. The maintenance mode also keeps the two P/R modules synchronized in the presence of thermal disturbances, P/R Belt stretch, and measurement errors, etc. Corrections will be made to the slave print engine to make it follow the master print engine. All corrections performed on-line (i.e. while making prints) must be done in such a way as to minimize their registration effects. The corrections include the following steps. The phase difference between the two seam signals can be measured on each belt revolution. As known to those skilled in the art, any necessary filtering is applied to the feedback. The filtered phase difference is compared to the desired phase difference and an error is formed. The control law can be applied to the error signal and a new slave velocity can be calculated. The new MPA velocity is then calculated based on the changes to the new P/R module velocity. Updates are made to the slave velocity such that registration impacts are minimized. Updates can also be made to the MPA clock if the resolution is available. If the resolution is not available, then changes are made when the velocity of the P/R module has shifted sufficiently that the absolute process magnification is out by the maximum target (i.e. 4 mm). The slave paper registration system can be periodically polled for the average correction being made. If the average correction is >±4 mm, for example, from zero then the additional position error is slowly added (subtracted) from the phase reference (T phase ) to fine tune the desired phase relationship. This is done to help the paper registration system keep the corrections centered around 0 mm. The corrections are then repeated on the next belt revolution.
Minimizing the start-up transient of the tandem print engine configuration is desirable and is facilitated by parking the P/R belts in the proper phase relationship. The belts can be stopped independently as long as they are parked in the proper orientation as described above.
The tandem architecture described above can work for any size paper once the phase delay is set up. For the system to be independent of paper size, a constant delay intermediate inverter paper path can be used. It is to be appreciated that the intermediate inverter paper path can maintain a constant time period to move the substrate from transfer zone 1 (on the master print engine) to transfer zone 2 (on the slave print engine).
While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents.
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An image processing apparatus including tandem print engines is provided for forming an image on an image receiving substrata. The apparatus includes a first print engine and a second print engine downstream from the first print engine. The second print engine is slaved to the first print engine. The first print engine has a first photoreceptor and a first period of revolution. The second print engine has a second photoreceptor and a second period of revolution. The image processing apparatus further includes an intermediate inverter that inverts the image receiving substrate between the first print engine and the second print engine. The inverter determines a phase difference between a first seam signal from the first photoreceptor and a second seam signal from the second photoreceptor.
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BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for controlling the supply of fuel to selected cylinders of all of and the operation of inlet and exhaust valves of the selected cylinders of a multi-cylinder internal combustion engine.
A known apparatus for controlling the supply of fuel to selected cylinders of all of and the operation of inlet and exhaust valves of the selected cylinders of a multi-cylinder internal combustion engine comprises electrically energizable fuel injectors for all cylinders of the engine, respectively, and adapted when energized to discharge fuel adjacent the inlet valves, respectively, for induction into all of the cylinders. An engine load detection device is provided to detect a predetermined control element in which the engine is to run on selected cylinders of all and a control circuit is provided to disable the fuel injectors of the remaining cylinders. The apparatus also comprises an valve operating device effective to disable the operation of the inlet and exhaust valves for the remaining cylinders to maintain them in their closed position as long as the engine load detection device detects the predetermined control event.
A problem encountered in this known control apparatus is that, when the engine is to be decelerated while the engine runs on the selected cylinders of all, the effective engine braking can not be obtained since the disabled cylinders do not pump air.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to improve the apparatus as mentioned above by eliminating the problem encounted with it.
According to the present invention, there are provided detector to detect a predetermined control event in which the engine is to be decelerated and means for restoring the normal operation of the disabled inlet and exhaust valves to let the disabled cylinders to pump air when the detector detects the predetermined control event while the engine is running on the selected cylinders of all.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of an apparatus for controlling the supply of fuel to cylinders of and the operation of inlet and exhaust valves of a multi-cylinder internal combustion engine;
FIG. 2 is a diagram explaining the operation modes of the apparatus; and
FIG. 3 is a schematic view of the section of the apparatus which controls the operation of inlet and exhaust valves.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In this preferred embodiment, an electronic fuel injection control system for a 6-cylinder internal combustion engine is employed, which supplies fuel to selected three cylinders of all through three fuel injection nozzles, respectively, when the engine operates at three-cylinder mode. Supply of fuel to the other three cylinders is cut and a pair of inlet and exhaust valves associated with each of these cylinders are maintained fully closed when the engine run on three cylinders.
In FIG. 1, a first throttle switch 1, which is designed to detect a light load, is operatively connected with a throttle blade or valve to produce a high level signal "1" when the throttle opening degree is smaller than a predetermined relatively small opening degree θ 1 .
A second throttle switch 2, which is designed to detect a high or heavy load, is operatively connected with the throttle valve also to produce a high level signal "1" when the throttle opening degree is greater than a predetermined relatively great opening degree θ 2 .
An engine speed switch 3, which is designed to detect a low engine speed range, produces a high level signal "1" when the engine speed is lower than a predetermined low speed N O .
When it is desired to effect engine braking operation during 3-mode engine operation under light load so as to rapidly decelerate the vehicle, the operation of the inlet and exhaust valves associated with the deactivated cylinders will be restored. For this purpose, a detector or switch 4 is provided which detects a condition where the engine braking is demanded, such as operating condition of a foot brake pedal, or return speed of an accelerator pedal (whether the return speed exceeds a predetermined level or not). The detector 4 switces its output from a high level signal "1" to a low level signal "0" upon detection of such a condition and produces the low level signal "0" while it detects such the condition.
The reference numeral 5 is an OR circuit which produces a high level signal "1" when at least one of its inputs from the switches 2 and 3, respectively, switches from a low level signal "0" to a high level signal "1".
The reference numeral 6 is a flip-flop circuit which has its set input terminal (S) connected to the switch 1 to receive the output therefrom and its reset input terminal (R) connected to the OR circuit 5 to receive the output therefrom. As is well known, the flip flop 6 switches an output on its Q output terminal from a low level signal "0" to a high level signal "1" when the set input switches to a high level signal "1", and return to the low level signal "0" when the reset input switches to a high level signal "1".
As will now be understood, the throttle switches 1 and 2, the speed switch 3, the OR circuit 5 and the flip flop circuit 6 constitute a load detection device A which detects an engine operating condition under light load.
An AND circuit 7 produces an output when the outputs of the flip flop 6 and the detector 4 are at high level signals "1", the output from the AND circuit 7 being amplified at an amplifier 8 before supplied to solenoid actuated switching valves 9, 10 and 11 to operate them.
These solenoid valves 9, 10 and 11 are associated with three pairs of inlet and exhaust valves for three cylinders, respectively to disable the inlet and exhaust valves to maintain them in fully closed condition when the output from the AND circuit 7 is at a high level signal "1".
The Q output from the flip flop circuit 6 is supplied through an amplifier 12 to a relay 13 to energize a relay coil 13b thereof when a high level signal "1" appears as Q output. The relay 13 has a normally closed switching contact 13a which forms part of a signal transmitting line from an output of a fuel injection control unit 14 to three fuel injection valves 15, 16 and 17 for the three cylinders associated with solenoid valves 9, 10 and 11. When opened by energization of the relay coil 13b, the contacts 13a stop fuel injection via these fuel injection valves.
FIG. 2 shows an apparatus 19 to deactivate an inlet valve and an exhaust valve 20. In this Figure, the reference numeral 21 designates a cylinder head, the reference numeral 22 a valve shaft, the reference numeral 23 a valve spring, the reference numeral 24 a rocker arm rockable under the control of a cam 25 against the bias of the valve spring 24 to open the valve, and the reference numeral 26 a rocker pivot on which the rocker arm 24 is mounted, by means of a spring clamp 24a, for rockable movement about a rounded top of the rocker pivot 26, (see FIG. 2).
The rocker pivot 26 has at its lower portion a piston section 27 integrally formed therewith. The piston section 27 is slidably disposed in a cylinder 28 to divide the cylinder into a lower and upper pressure chambers 29a and 29b, the lower side and the upper side of the piston section 27 communicating with or being exposed to the lower and upper pressure chambers 29a and 29b, respectively. By selectively applying pressure to the pressure chambers 29a and 29b the rocker pivot 26 will move upwardly or downwardly, viewing in FIG. 2.
Explaining more specifically, under the control of a switching valve 9, the pressure is applied to the pressure chambers 29a and 29b alternatively. There are provided three such switching valves and their associated control circuit for the rocker pivots corresponding to three cylinders, respectively. As previously described the outputs of the load detection device A of the deceleration detector 4 are fed to the inputs of the AND circuit 7. The output of the AND circuit 7 is fed to each of the solenoid valve 9 via an amplifier 8 to actuate the same. Under the illustrated condition in FIG. 2, the pressure from the source of pressure 30 is supplied or applied to the lower pressure chamber 29a to maintain the rocker pivot 26 in the illustrated elevated position in which the appropriate operation of the pair of inlet and exhaust valves, such as shown at 20, is possible, that is, rotation of the cam 25 will cause the rocker arm 24 to rock to open and close the valve 20.
When the output of the AND circuit 7 is at a logical 1, the switching valve 9 switches its condition to cut off fluid communication between the lower pressure chamber 29a and the source of pressure 30 and establishes fluid communication between the upper chamber 29b and the source of pressure 30, thus lowering the rocker pivot 26 toward an inoperable position in which the rocker arm 24 is out of contact with the cam 25 so that rotating the cam 25 will not cause the rocker arm 24 to tap the valve 20. As a result, the bias of the valve spring 23 the valve is maintained in its fully closed position.
In the construction previously described, under light load engine operating condition in which the throttle opening degree is smaller than θ 1 the output of the switch 1 switches to a high level signal "1" to cause the flip flop circuit 6 to produce a high level signal "1" as its Q output, then the relay 13 is energized to open the normally closed contacts 13a to stop operation of the fuel injection valves 15, 16 and 17. Under this condition, unless the brake is actuated the output of the detector 4 is at a high level signal "1" so that the AND circuit 7 produces a high level signal "1" as its output to cause the solenoid operated switch valves 9, 10 and 11 to change their state from the illustrated condition in FIG. 2 to maintain the inlet and exhaust valves of the deactivated three cylinders in fully closed condition.
Under relatively high or heavy load engine operating condition in which the throttle opening degree is larger than θ 2 or under engine operating condition at low engine speed in which the engine revolution speed is lower than N O , the output of the OR circuit becomes a high level signal "1" so as to reset the flip-flop circuit 6 to cause it to produce a low level signal "0" as its Q output. Under this condition, since the energization of the relay 13 ceases to permit the contacts 13a to be closed again so that the operation of the fuel injection valves 15, 16 and 17 resume and since the output of the AND circuit 7 becomes a low level signal "0", the solenoid operated switching valves 9, 10 and 11 return to the illustrated condition in FIG. 2. Thus, the inlet and exhaust valves 20 of the three cylinders operate appropriately and the engine operates at 6-cylinder mode.
When the brake is actuated or stepped on while the Q output of the flip flop circuit 6 is at a high level signal "1", that is, when the engine operates under light load and at 3-cylinder mode operation, the output of the detector 4 becomes a low level signal "0" so as to cause the AND circuit 7 to produce a low level signal "0" as its output so that owing to the switching valves 9, 10 and 11 the operation of the inlet and exhaust valves 20 for the deactivated cylinders resumes. Since, then, the Q output of the flip flop circuit 6 remains at a high level signal "1", the solenoid 13 is maintained in energized condition so that the fuel supply through the fuel injectors to the deactivated cylinders will not resume. Thus, the deactivated cylinders to which fuel supply is cut perform pumping action by operating their inlet and exhaust valves to increase engine braking effect to meet rapid deceleration requirement.
Under mild decelerating engine operating condition with the brake being not actuated, that is, for example during coasting (running of the vehicle by its inertia) from high speed running condition, the output of the AND circuit 7 remains at high level signal "1" so that the inlet and exhaust valves for the deactivated cylinders will not resume their operation under this condition. Thus, the engine braking effect resulting from the three activated cylinders is provided which meets the practical requirements under this operating condition.
It will be recognized that actuating or stepping on the brake will always cause all of the inlet and exhaust valves for all cylinders to operate appropriately because the output of the AND circuit 7 becomes a low level signal "0" when the brake is actuated regardless of the outputs of the switches 1, 2 and 3.
The operation when the throttle opening degree is between θ 1 and θ 2 will be described hereinafter. When the engine operating condition enters this region while increasing the amount of load imposed on the engine, 6-cylinder mode engine operation will be maintained because the Q output of the flip flop 6 remains at a low level signal "0" until the throttle switch 1 supplies a high level signal "1" to the set terminal of the flip flop circuit 6. When the engine operating condition enters this region which decreasing the amount of load imposed on the engine, 3-cylinder mode engine operation will be maintained until throttle switches switch 2 supplies a high level signal "1" to the reset terminal of the flip flop circuit 6. Even under these conditions, all of the inlet and exhaust valves for all of the cylinders will operate when the brake is actuated.
The above described operating conditions are visualized as a pattern B or C as shown in FIG. 3.
Although the detector 4 used in the embodiment is responsive to the actuation of the brake to detect the engine braking requirement, such requirement may be detected by the return rate or speed of an accelerator pedal. Thus a detector which detects such speed rate may be alternatively used as the detector 4.
In a fuel injection control process in which width of the fuel injection pulse is determined proportional to the total of the intake air supplied to the engine, with the same load switching from the 6-cylinder mode engine operating condition to 3-cylinder mode engine operating condition may result in a loss of the engine power output or misfire, because such switching will not alter the quantity of fuel injected to activated cylinders even if the quantity of air to be supplied to the deactivated cylinders will be distributed to the activated cylinders evenly.
This problem may be solved by increasing or doubling the injection pulse width in response to this switching
Although the invention has been described in connection with 6-cylinder engine, the invention may be equally applied to other multi cylinder engine such as 4-cylinder or 8-cylinder engine.
Each of the switches 1, 2, 3 and 4 may be replaced with a unit including a device detecting an analog amount and a comparator which produces a high or low level signal as an output when the measure analog amount exceeds or is below a predetermined value.
The determination of light load engine operation may be made by detecting the width of the fuel injection pulse or detecting the magnitude of the intake depression or vacuum.
The invention may be applied to an engine with carburetor induction. In this case during deceleration the engine may be controlled to operate on 6-cylinder mode during deceleration.
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An apparatus for controlling the operation of inlet and exhaust valves and the supply of fuel to selected cylinders of all of a multi-cylinder internal combustion engine. The inlet and exhaust valves for induction and exhaust of the selected cylinders of all are closed and the supply of fuel to them is cut off to operate the engine on the remaining cylinders of all. According to the invention, a detector to detect a predetermined control event in which the engine is to be decelerated is provided. Also provided is a valve operation restoring device for causing restoration of the disabled valves when said detector detects the predetermined control event to let the disabled cylinders to pump air to achieve effective engine braking.
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The present application is a 37 C.F.R. §1.53(b) continuation of U.S. patent application Ser. No. 12/985,389 filed on Jan. 6, 2011, which is a 37 C.F.R. §1.53(b) continuation of U.S. patent application Ser. No. 12/639,872 filed on Dec. 16, 2009, now U.S. Pat. No. 7,930,910 B2, which is a 37 C.F.R. §1.53(b) continuation of U.S. patent application Ser. No. 12/267,457 filed Nov. 7, 2008, which is a 37 C.F.R. §1.53(b) continuation of U.S. patent application Ser. No. 10/461,451 filed Jun. 16, 2003, now U.S. Pat. No. 7,533,548 B2, which claims priority to Korean Patent Application No. 85521/2002, filed Dec. 27, 2002, the entire contents of which are hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drum type washing machine, and more particularly, to a drum type washing machine which can maximize a capacity of a drum without changing an entire size of a washing machine.
2. Description of the Related Art
FIG. 1 is a side sectional view showing a drum type washing machine in accordance with the conventional art, FIG. 2 is a front sectional view showing the drum type washing machine in accordance with the conventional art.
The conventional drum type washing machine comprises: a cabinet 102 for forming an appearance; a tub 104 arranged in the cabinet 102 for storing washing water; a drum 106 rotatably arranged in the tub 104 for washing and dehydrating laundry; and a driving motor 110 positioned at a rear side of the tub 104 and connected to the drum 106 by a driving shaft 108 thus for rotating the drum 106 .
An inlet 112 for inputting or outputting the laundry is formed at the front side of the cabinet 102 , and a door 114 for opening and closing the inlet 112 is formed at the front side of the inlet 112 .
The tub 104 of a cylindrical shape is provided with an opening 116 at the front side thereof thus to be connected to the inlet 112 of the cabinet 102 , and a balance weight 118 for maintaining a balance of the tub 104 and reducing vibration are respectively formed at both sides of the tub 104 .
Herein, a diameter of the tub 104 is installed to be less than a width of the cabinet 102 by approximately 30-40 mm with consideration of a maximum vibration amount thereof so as to prevent from being contacted to the cabinet 102 at the time of the dehydration.
The drum 106 is a cylindrical shape of which one side is opened so that the laundry can be inputted, and has a diameter installed to be less than that of the tub 104 by approximately 15-20 mm in order to prevent interference with the tub 104 since the drum is rotated in the tub 104 .
A plurality of supporting springs 120 are installed between the upper portion of the tub 104 and the upper inner wall of the cabinet 102 , and a plurality of dampers 122 are installed between the lower portion of the tub 104 and the lower inner wall of the cabinet 102 , thereby supporting the tub 104 with buffering.
A gasket 124 is formed between the inlet 112 of the cabinet 102 and the opening 116 of the tub 104 so as to prevent washing water stored in the tub 104 from being leaked to a space between the tub 104 and the cabinet 102 . Also, a supporting plate 126 for mounting the driving motor 110 is installed at the rear side of the tub 104 .
The driving motor 110 is fixed to a rear surface of the supporting plate 126 , and the driving shaft 108 of the driving motor 110 is fixed to a lower surface of the drum 106 , thereby generating a driving force by which the drum 106 is rotated.
In the conventional drum type washing machine, the diameter of the tub 104 is installed to be less than the width of the cabinet 102 with consideration of the maximum vibration amount so as to prevent from being contacted to the cabinet 102 , and the diameter of drum 106 is also installed to be less than that of the tub 104 in order to prevent interference with the tub 104 since the drum is rotated in the tub 104 . According to this, so as to increase the diameter of the drum 106 which determines a washing capacity, a size of the cabinet 102 has to be increased.
Also, since the gasket 124 for preventing washing water from being leaked is installed between the inlet 112 of the cabinet 102 and the opening 116 of the tub 104 , a length of the drum 106 is decreased as the installed length of the gasket 124 . According to this, it was difficult to increase the capacity of the drum 106 .
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a drum type washing machine which can increase a washing capacity without changing an entire size thereof, in which a cabinet and a tub is formed integrally and thus a diameter of a drum can be increased without increasing a size of the cabinet.
Another object of the present invention is to provide a drum type washing machine which can increase a washing capacity by increasing a length of a drum without increasing a length of a cabinet, in which the cabinet and a tub are formed integrally and thus a location of a gasket is changed.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a drum type washing machine comprising: a cabinet for forming an appearance; a tub fixed to an inner side of the cabinet and for storing washing water; a drum rotatably arranged in the tub for washing and dehydrating laundry; and a driving motor positioned at the rear side of the drum for generating a driving force by which the drum is rotated.
The tub is a cylindrical shape, and a front surface thereof is fixed to a front inner wall of the cabinet.
Both sides of the tub are fixed to both sides inner wall of the cabinet.
A supporting plate for mounting the driving motor is located at the rear side of the tub, and a gasket hermetically connects the supporting plate and the rear side of the tub, in which the gasket is formed as a bellows and has one side fixed to the rear side of the tub and another side fixed to an outer circumference surface of the supporting plate.
A supporting unit for supporting an assembly composed of the drum, the driving motor, and the supporting plate with buffering is installed between the supporting plate and the cabinet.
The supporting unit comprises: a plurality of upper supporting rods connected to an upper side of the supporting plate towards an orthogonal direction and having a predetermined length; buffering springs connected between the upper supporting rods and an upper inner wall of the cabinet for buffering; a plurality of lower supporting rods connected to a lower side of the supporting plate towards an orthogonal direction and having a predetermined length; and dampers connected between the lower supporting rods and a lower inner wall of the cabinet for absorbing vibration.
The drum is provided with a liquid balancer 32 at a circumference of an inlet thereof for maintaining a balance when the drum is rotated.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
In the drawings:
FIG. 1 is a side sectional view showing a drum type washing machine in accordance with the conventional art;
FIG. 2 is a front sectional view showing the drum type washing machine in accordance with the conventional art;
FIG. 3 is a side sectional view showing a drum type washing machine according to one embodiment of the present invention;
FIG. 4 is a front sectional view showing the drum type washing machine according to one embodiment of the present invention;
FIG. 5 is a lateral view showing a state that a casing of the drum type washing machine according to one embodiment of the present invention is cut;
FIG. 6 is a front sectional view of a drum type washing machine according to a second embodiment of the present invention;
FIG. 7 is a front sectional view showing a drum type washing machine according to a third embodiment of the present invention;
FIG. 8 is a longitudinal sectional view of the drum type washing machine according to the third embodiment of the present invention; and
FIG. 9 is a rear sectional view showing the drum type washing machine according to the third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
FIG. 3 is a side sectional view showing a drum type washing machine according to one embodiment of the present invention, and FIG. 4 is a front sectional view showing the drum type washing machine according to one embodiment of the present invention.
The drum type washing machine according to one embodiment of the present invention comprises: a cabinet 2 for forming an appearance of a washing machine; a tub 4 formed integrally with the cabinet 2 and for storing washing water; a drum 6 rotatably arranged in the tub 4 for washing and dehydrating laundry; and a driving motor 8 positioned at the rear side of the drum 6 for generating a driving force by which the drum 6 is rotated.
The cabinet 2 is rectangular parallelepiped, and an inlet 20 for inputting and outputting laundry is formed at the front side of the cabinet 2 and a door 10 for opening and closing the inlet 20 is formed at the inlet 20 .
The tub 4 is formed as a cylinder shape having a predetermined diameter in the cabinet 2 , and the front side of the tub 4 is fixed to the front inner wall of the cabinet 2 or integrally formed at the front inner wall of the cabinet 2 . Both sides of the tub 4 are contacted to both sides inner wall of the cabinet 2 or integrally formed with both sides inner wall of the cabinet 2 thus to be prolonged.
Herein, since both sides of the tub 4 are contacted to both sides inner wall of the cabinet 2 , a diameter of the tub 4 can be increased.
Also, the supporting plate 12 is positioned at the rear side of the tub 4 and the gasket 14 is installed between the supporting plate 12 and the rear side of the tub 4 , thereby preventing washing water filled in the tub 4 from being leaked.
The gasket 14 is formed as a bellows of a cylinder shape and has one side fixed to the rear side of the tub 4 and another side fixed to an outer circumference surface of the supporting plate 12 .
The supporting plate 12 is formed as a disc shape, the driving motor 8 is fixed to the rear surface thereof, and a rotation shaft 16 for transmitting a rotation force of the driving motor 8 to the drum 6 is rotatably supported by the supporting plate 12 . Also, a supporting unit for supporting the drum 6 with buffering is installed between the supporting plate 12 and the inner wall of the cabinet 2 .
The supporting unit comprises: a plurality of upper supporting rods 22 connected to an upper side of the supporting plate 12 and having a predetermined length; buffering springs 24 connected between the upper supporting rods 22 and an upper inner wall of the cabinet 2 for buffering; a plurality of lower supporting rods 26 connected to a lower side of the supporting plate 12 and having a predetermined length; and dampers 28 connected between the lower supporting rods 26 and a lower inner wall of the cabinet 2 for absorbing vibration.
Herein, the buffering springs 24 and the dampers 28 are installed at a center of gravity of an assembly composed of the drum 6 , the supporting plate 12 , and the driving motor 8 . That is, the upper and lower supporting rods 22 and 26 are prolonged from the supporting plate 12 to the center of gravity of the assembly, the buffering springs 24 are connected between an end portion of the upper supporting rod 22 and the upper inner wall of the cabinet 2 , and the dampers 28 are connected between an end portion of the lower supporting rod 26 and the lower inner wall of the cabinet 2 , thereby supporting the drum 6 at the center of gravity.
A diameter of the drum 6 is installed in a range that the drum 6 is not contacted to the tub 4 even when the drum 6 generates maximum vibration in order to prevent interference with the tub 4 at the time of being rotated in the tub 4 .
Operations of the drum type washing machine according to the present invention are as follows.
If the laundry is inputted into the drum 6 and a power switch is turned on, washing water is introduced into the tub 6 . At this time, the front side of the tub 6 is fixed to the cabinet 2 and the gasket 14 is connected between the rear side of the tub 6 and the supporting plate 12 , thereby preventing the washing water introduced into the tub 6 from being leaked outwardly.
If the introduction of the washing water is completed, the driving motor 8 mounted at the rear side of the supporting plate 12 is driven, and the drum 6 connected with the driving motor 8 by the rotation shaft 16 is rotated, thereby performing washing and dehydration operations. At this time, the assembly composed of the drum 6 , the driving motor, and the supporting plate 12 is supported by the buffering springs 24 and the dampers 28 mounted between the supporting plate 12 and the inner wall of the cabinet 20 .
FIG. 6 is a front sectional view of a drum type washing machine according to a second embodiment of the present invention.
The drum type washing machine according to the second embodiment of the present invention has the same construction and operation as that of the first to embodiment except a shape of the tub.
That is, the tub 40 according to the second embodiment has a straight line portion 42 with a predetermined length at both sides thereof. The straight line portion 42 is fixed to the inner wall of both sides of the cabinet 2 , or integrally formed at the wall surface of both sides of the cabinet 2 .
Like this, since the tub 40 according to the second embodiment has both sides fixed to the cabinet 2 as a straight line form, the diameter of the tub 40 can be increased. Accordingly, the diameter of the drum 6 arranged in the tub 40 can be more increased.
FIG. 7 is a front sectional view showing a drum type washing machine according to a third embodiment of the present invention, FIG. 8 is a longitudinal sectional view of the drum type washing machine according to the third embodiment of the present invention, and FIG. 9 is a rear sectional view showing the drum type washing machine according to the third embodiment of the present invention.
The drum type washing machine according to the third embodiment of the present invention comprises: a cabinet 2 for forming an appearance of a washing machine; a tub 50 formed integrally with the cabinet 2 and for storing washing water; a drum 6 rotatably arranged in the tub 50 for washing and dehydrating laundry; and a supporting unit positioned at the rear side of the tub 50 and arranged between the supporting plate 12 to which the driving motor 8 is fixed and the cabinet 2 for supporting the drum 6 with buffering.
The tub 50 is composed of a first partition wall 52 fixed to the upper front inner wall and both sides inner wall of the cabinet 2 ; and a second partition wall 54 integrally fixed to the lower front inner wall and both sides inner wall of the cabinet 2 .
The first partition wall 52 of a flat plate shape is formed at the upper side of the cabinet 2 in a state that the front side and both sides are integrally formed at the inner wall of the cabinet 2 or fixed thereto. Also, the second partition wall 54 of a semi-circle shape is formed at the lower side of the cabinet 2 in a state that the front side and both sides are integrally formed at the inner wall of the cabinet 2 or fixed thereto.
The supporting unit comprises: a plurality of upper supporting rods 56 connected to the upper side of the supporting plate 12 and having a predetermined length; buffering springs 58 connected between the upper supporting rods 56 and the upper inner wall of the cabinet 2 for buffering; a plurality of lower supporting rods 60 connected to the lower side of the supporting plate 12 and having a predetermined length; and dampers 62 connected between the lower supporting rods 60 and the lower inner wall of the cabinet 2 for absorbing vibration.
Herein, the upper supporting rods 56 are bent to be connected to the upper side of the supporting plate 12 and positioned at the upper side of the first partition wall 52 , and the buffering springs 58 are connected to the end portion of the upper supporting rods 56 . Also, the lower supporting rods 60 are bent to be connected to the lower side of the supporting plate 12 and positioned at the lower side of the second partition wall 54 , and the dampers 62 are connected to the end portion of the lower supporting rods 56 .
In the drum type washing machine according to the present invention, a size of the drum can be maximized by fixing the tub in the cabinet, thereby increasing washing capacity of the drum without increasing a size of the cabinet.
Also, since the front surface of the tub is integrally formed at the inner wall of the cabinet and the gasket is installed between the rear surface of the tub and the supporting plate, a length of the drum can be increased and thus the washing capacity of the drum can be increased.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.
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A drum type washing machine is provided. The drum type washing machine may include a cabinet, a tub fixed to an inner side of the cabinet, a drum rotatably arranged in the tub, and a driving motor positioned at a rear side of the drum for generating a driving force that rotates the drum. The washing machine may also include a supporting plate to rotatably support a rotational shaft extending between the motor and the drum, and a plurality of supporters connected between the supporting plate and the cabinet. Such an arrangement may increase washing capacity by increasing a diameter of the drum without increasing an external size of the cabinet.
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TECHNICAL FIELD
[0001] The present invention relates to a foam storage and proportionally mixing device for a fire extinguisher system, and particularly to an alternate foam storage and proportionally mixing device, by which foam liquid is alternatively injected into at least two pressure foam tanks by means of at least one normal pressure foam storage tank, and the foam liquid from the at least two pressure foam tanks alternatively and continuously produce mixed foam liquid through at least one proportional mixer for the foam fire extinguisher system. The device can be manufactured in a standard manner while not only achieving accurate proportion of mixture of the foam liquid, but can be produced in a simple structure. In addition, the rubber diaphragm tends not to be easily broken. Also, the production cycle is relatively short.
DESCRIPTION OF THE RELATED ART
[0002] There exist two types of foam storage and proportionally mixing devices widely used in the current market, namely, pressure foam storage and proportionally mixing device made of flexible rubber diaphragm, and foam storage and proportionally mixing device of balance pressure regulation, as respectively shown in FIGS. 1 and 2 .
[0003] FIG. 1 shows a pressure foam storage and proportionally mixing device of the prior art, comprising one pressure foam tank 1 for storing the foam liquid, a proportional mixer 2 , a water supply pipe 8 , a water intake valve 3 , a water outlet valve 7 , and a liquid outlet valve 4 . The water flowing through the water supply pipe 8 is divided into two portions, one of which flows into the pressure tank 1 through the water intake valve 3 to force the foam liquid stored in advance in the tank 1 into the proportional mixer 2 via the liquid outlet valve 4 through the pipe 5 , while the other one of which flows directly into the proportional mixer, 2 through the water supply pipe 8 . The two portions of liquid are mixed in the proportional mixer 2 to produce a mixed foam liquid in a predetermined proportion of mixture for output. The device is advantageous in the accurate proportion of mixture due to the pressure foam tank and the simple structure. However, because the foam storage tank is in the form of a pressure foam tank, and thus is a pressure container, it has a disadvantage of a long production cycle. Also, because the foam tank is made of rubber diaphragm, it is likely to be broken when it is filled with foam under pressure, and it is more likely to be broken as the tank becomes larger.
[0004] FIG. 2 shows a foam storage and proportionally mixing device of balance pressure regulation in the prior art, comprising a normal pressure tank 15 , a proportional mixer 12 , a foam liquid pump 14 , a water pump 16 and an electric control device 17 . Various flow parameters such as flux of the foam liquid of the foam liquid pump 14 and the flux of the water pump 16 are measured at first, and then the balance pressure proportional mixer 12 is controlled to output mixed foam liquid according to the various flow parameters. Therefore, it has the advantage of high accuracy of proportion of mixture. Also, since the foam liquid storage tank 14 is a normal pressure tank, the design cycle is shortened. However, the preciseness of the measurement of the parameters and the control may be difficult, that is, sophisticate devices have to be used, thereby increasing the cost.
[0005] The above two foam storage and proportionally mixing devices have their respective pros and cons. In order to overcome the disadvantages of long production cycle and tendency to be broken in the flexible rubber diaphragm pressure foam storage and proportionally mixing device, and the disadvantages of difficulty in achieving precise measurement of the parameters and control as well as the high cost in the foam storage and proportionally mixing device of balance pressure regulation, the present invention provides an alternate foam tank and a proportionally mixing device.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to provide an alternate foam storage and proportionally mixing device, which has the advantages of simple structure and precisely mixing, and is capable to overcome the disadvantages of the long production cycle, the rubber diaphragm being likely to be broken, and difficulty in achieving precise measurement of parameters and precise control.
[0007] An alternate foam storage and proportionally mixing device according to the present invention comprising at least one normal pressure foam storage tank, at least two pressure foam tanks, at least one proportional mixer, and a control unit. By using the at least one normal pressure foam storage tank to alternatively inject the foam liquid to the at least two pressure foam tanks, the at least two pressure foam tanks alternatively output the foam liquid to the at least one proportional mixer, which then outputs the mixed foam liquid. Therefore, the foam liquid of the at least two pressure foam tanks are alternatively and continuously output through the at least one proportional mixer to produce the mixed foam liquid for the foam fire extinguisher system.
[0008] In the alternate foam storage and proportionally mixing device according to the present invention, whilst one pressure foam tank outputs the foam liquid to the proportional mixer, the at least one normal pressure foam storage tank replenishes liquid to another pressure foam tank.
[0009] The alternate foam storage and proportionally mixing device according to the present invention further includes at least two proportional mixers, wherein the pressure foam tanks and the proportional mixers are provided on one-to-one basis, and each of the pressure foam tanks alternatively outputs the foam liquid to the corresponding proportional mixer, and each of the proportional mixer alternatively outputs the mixed foam liquid.
[0010] The alternate foam storage and proportionally mixing device according to the present invention further includes at least two foam storage tanks for outputting the foam liquid to the pressure foam tanks. The pressure foam tanks and the foam storage tanks may be provided on one-to-one basis, and the foam storage tanks alternatively output the foam liquid to their respective pressure foam tanks.
[0011] The alternate foam storage and proportionally mixing device according to the present invention has the following advantages over the prior art:
[0012] 1. Since the foam storage tank according to the present invention is a normal pressure tank, and there are at least two pressure foam tanks, the probability of destruction of the rubber diaphragm is greatly decreased. Moreover, the pressure foam tank can be designed in a standard manner, and thus the production can be standardized. Therefore, the present invention can have a short design cycle, and can be manufactured, installed and adjusted easily.
[0013] 2. Since in the present invention, the normal pressure foam storage tanks are used to store the foam liquid and the pressure foam tanks are used to output the foam liquid, the present invention has the advantages of both aforesaid prior arts, such as simple structure and preciseness of the mixture of the foam liquid, while eliminating the disadvantages of the prior art, such as the difficulty in achieving preciseness of parameter measurement and control. Thus, the present invention has a good economical efficiency.
BRIEF DESCRIPTION OF THE DRAWING
[0014] The present invention will be further described below with reference to the accompanying drawings and the preferred embodiments.
[0015] FIG. 1 is a schematic view of a conventional flexible rubber diaphragm pressure foam storage and proportionally mixing device in the prior art;
[0016] FIG. 2 is a schematic view of a conventional foam storage and proportionally mixing device of balance pressure regulation in the prior art;
[0017] FIG. 3 is a schematic view of a foam storage and proportionally mixing device according to an embodiment of the present invention;
[0018] FIG. 4 is a schematic view of a foam storage and proportionally mixing device according to a further embodiment of the present invention;
[0019] FIG. 5 is a schematic view of a foam storage and proportionally mixing device according to a still further embodiment of the present invention; and
[0020] FIG. 6 is schematic structure view of a piston foam tank according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] FIG. 3 schematically shows a foam storage and proportionally mixing device according to an embodiment of the present invention. In the embodiment shown in FIG. 3 , the foam storage and proportionally mixing device comprises a foam storage tank 12 , pressure foam tanks 1 , 1 a , a proportional mixer 2 , water intake valves 3 , 3 a , water outlet valves 7 , 7 a , liquid outlet valves 4 , 4 a , a water supply pipe 8 , liquid supply valves 10 , 10 a , air outlet valves 11 , 11 a , a control unit (not shown). As shown in FIG. 3 , the foam storage tank 12 is connected to the pressure foam tanks 1 , 1 a for injecting foam liquid into the pressure tanks 1 , 1 a . The pressure foam tanks 1 , 1 a are connected to the proportional mixer 2 via a pipe 5 to output the foam liquid thereto. The water supply pipe 8 is connected to the pressure foam tanks 1 , 1 a as well as the proportional mixer 2 to supply water thereto.
[0022] In the alternate foam storage and proportionally mixing device for a foam fire extinguisher system according to the present invention, at least one normal foam storage tank 12 injects foam liquid to the two pressure foam tanks 1 , 1 a alternatively, and the foam liquid of the two pressure tanks 1 , 1 a alternatively and continuously produce mixed foam liquid for the foam fire extinguisher system via a proportional mixer 2 . The foam storage tank 12 is a normal pressure tank (such as a metal tank, a plastic tank, a barrel having a rated pressure of 0-0.6 MPa). The pressure foam tanks 1 , 1 a may be piston pressure tanks or pressure tanks provided with a flexible rubber diaphragm, and have a rated pressure greater than 0.6 MPa and a volume in a range of 0.2 to 0.3 m 3 .
[0023] When the foam fire extinguisher system is not in operation as a normal condition, the foam liquid is stored in the normal pressure foam storage tank 12 , while the pressure foam tank 1 and 1 a is filled with foam liquid. Thus, the water intake valves 3 , 3 a , water outlet valves 7 , 7 a , liquid supply valves 10 , 10 a , air outlet valves 11 , 11 a , liquid outlet valves 4 , 4 a are closed. The liquid outlet valves 4 , 4 a may be one-way valves or electric control valves.
[0024] When the foam fire extinguisher system is activated, extinguishing water at certain pressure flows into the water supply pipe 8 . The extinguishing water is divided into two portions when entering the proportional mixer 2 . The control unit (not shown) sends a signal to open the water intake valve 3 and the liquid outlet valve 4 . One portion of the water flows into the pressure foam tank 1 , and forces the foam liquid pre-stored in the rubber diaphragm of the pressure foam tank 1 into the proportional mixer 2 via the electric control valve (one-way valve) 4 and a porous plate 6 , while another portion of the water flows directly from the water supply pipe 8 into the proportional mixer 2 through a nozzle of the proportional mixer. Here the two parts of liquid are mixed in a predetermined proportion of mixture to produce a mixed foam liquid, which is then discharged to outside. When the control unit detects that the foam liquid stored in the pressure foam tank 1 has been discharged to a certain extent or for a certain time, the control unit sends a signal to close the water intake valve 3 and the liquid outlet valve 4 , and open the water intake valve 3 a , and the liquid outlet valve 4 a . The timing of the opening may be before, after or at the same as that of the closing.
[0025] After the water intake valve 3 a is opened, similar to the situation in which a portion of water flows into the pressure foam tank 1 through the water supply pipe 8 and the water intake valve 3 , at this time, one portion of the water flows into the pressure foam tank 1 a , and forces the foam liquid pre-stored in the rubber diaphragm of the pressure foam tank 1 a into the proportional mixer 2 via the electric control valve (one-way valve) 4 a and a porous plate 6 , while another portion of the water flows directly from the water supply pipe 8 into the proportional mixer 2 through a nozzle of the proportional mixer, thereby producing a mixed foam liquid in a predetermined proportion of mixture for output. When the foam liquid from the pressure foam tank 1 a is output to the proportional mixer 2 , the control unit sends a signal to open the liquid supply valve 10 , the air outlet valve 11 and the water outlet valve 7 of the foam tank 1 to inject the foam liquid stored in the form storage tank 12 is into the pressure foam tank 1 . Meanwhile, the air in the rubber diaphragm of the foam tank 1 may be discharged through the air outlet valve 11 , while the water in the pressure foam tank 1 may be discharged through the water outlet valve 7 . When the control unit detects that the foam liquid stored in the pressure foam tank 1 has been output to a certain extent or for a certain time, the control unit sends a signal to close the water intake valve 3 a and the liquid outlet valve 4 a such that the output from the foam tank 1 a to the proportional mixer 2 is stopped, and open the water intake valve 3 and the liquid outlet valve 4 such that the output from the foam tank 1 to the proportional mixer 2 is enabled. The timing of the opening may be before, after or at the same as that of the closing. The control unit opens the liquid supply valve 10 a , the air outlet valve 11 a and the water outlet valve 7 a of the foam tank 1 a , and the foam liquid stored in the foam storage tank 12 is injected into the pressure foam tank 1 a . As the aforesaid process repeats, the foam tank 12 injects the foam liquid into the pressure foam tanks 1 and 1 a alternatively, and the pressure foam tanks 1 and 1 a alternatively output the foam liquid into the proportional mixer 2 such that the mixed foam liquid is output from the proportional mixer continuously.
[0026] In the present invention, there are various implementations for injecting the foam liquid from the normal pressure foam storage tank 12 into the pressure foam tanks 1 and 1 a as desired or depend on the particular situation, such as the following implementations:
[0027] 1. Injection by head: The normal pressure foam storage tank is positioned at the level higher than the pressure foam tank such that the pressure caused by the head injects the foam liquid from the normal pressure foam storage tank into the pressure foam tank.
[0028] 2. Injection by pump: A foam pump (not shown) is connected to the foam storage tank and the pressure foam tank, and pumps the foam liquid stored in the normal pressure storage tank into the pressure foam tank.
[0029] 3. Injection by pneumatic pressure: A pressurizing device (not shown) is connected to the foam storage tank to force the foam liquid into the pressure foam tank by applying a pressurized gas to the liquid surface of the foam stored in the normal pressure foam storage tank.
[0030] Although in the aforesaid embodiment, only two pressure foam tanks 1 and 1 a are used to alternatively output the foam liquid to the proportional mixer 2 , it will be appreciated that more than two pressure foam tanks can be used in the present invention as desired, especially in the situation where the pressure foam tanks are designed in a number of standard configuration. That is, the foam tank may be standardized, and therefore the corresponding foam tank and the number thereof can be selected depend on requirements when designing, thereby greatly reducing the production cycle.
[0031] In the present invention, various pressure tanks may be used as the pressure foam tank as desired, such as flexible diaphragm pressure tank or piston pressure tank. A piston pressure tank is shown in FIG. 6 . The operation of the piston pressure tank is as follows. When injecting the foam liquid, the foam liquid is delivered into the pressure tank through a in-and-out foam liquid pipe 21 of the piston body 19 , and applies a pressure on the piston 20 so as to discharge the water in the pressure tank through an in-and-out water pipe 18 . When outputting the foam liquid, water is delivered into the pressure tank through the in-and-out water pipe 18 and applies a pressure on the piston 20 . The foam liquid in the pressure tank is output through the in-and-out foam liquid pipe 21 .
[0032] In the present invention, the output and replenishment of the foam liquid to a pressure foam tank may be detected by, but not limited to the following methods. Alterative method may be adopted as desired.
[0033] 1. Detection by flow meter: A foam liquid flow meter is disposed on the liquid supply pipe and the liquid outlet pipe for measurement. A flow meter may also be disposed following the water intake valve to measure the flux of the foam liquid by measuring the flux of the water. The supply of the foam liquid is stopped and the replenishment begins when the flux is less than a certain value.
[0034] 2. Timing control: The two pressure foam tank alternatively replenish and supply the liquid in a certain time interval. The operation thereof is controlled by timing.
[0035] 3. Position limiting measurement: A displacement switch is disposed on the piston or rubber wall of the pressure foam tank. The amount of the foam liquid in the pressure foam tank is measured by the position of the displacement switch.
[0036] Referring to FIG. 4 , which schematically shows a further embodiment of the foam storage and proportionally mixing device of the present invention, the difference between the present embodiment and the aforesaid embodiment lies in that in the present embodiment, the foam storage and proportionally mixing device comprises two foam storage tanks 12 , 12 a , which are connected to the two pressure foam tanks 1 , 1 a respectively, and correspond to the two pressure tanks 1 and 1 a respectively. The two foam storage tanks 12 , 12 a alternatively inject the foam liquid to the two respective pressure foam tanks 1 and 1 a . Other aspects of the present embodiment are the same with that of the aforesaid embodiment.
[0037] Referring to FIG. 5 , which schematically shows a still further embodiment of the foam storage and proportionally mixing device of the present invention, the difference between the present embodiment and the aforesaid embodiment lies in that in the present embodiment, the foam storage and proportionally mixing device comprises two proportional mixers 2 , 2 a , which are connected to the two pressure foam tanks 1 , 1 a respectively, and correspond to the two pressure tanks 1 and 1 a respectively. During operation, the foam liquid in the two pressure foam tank 1 , 2 a is alternatively and continuously output to their corresponding proportional mixers 2 , 2 a , which then alternatively output the mixed foam liquid for the foam fire extinguisher system. Moreover, the difference between the present embodiment and the aforesaid embodiments lies in that in the present embodiment, the water intake valves 3 , 3 a are disposed on the water supply pipes 8 , 8 a.
[0038] The embodiment will be described in detail with reference to FIG. 5 .
[0039] Before the foam storage and proportionally mixing device according to the present invention operates, that is, when the foam fire extinguisher system has not been activated, in a normal condition, the foam liquid is stored in the normal pressure foam storage tank 12 , while the pressure foam tanks 1 , 1 a are filled with foam liquid. Thus, water intake valves 3 , 3 a , water outlet valves 7 , 7 a , liquid supply valves 10 , 10 a , air outlet valves 11 , 11 a , liquid outlet valves 4 , 4 a are closed. The liquid outlet valves 4 , 4 a may be one way valves, and may also be electric control valves.
[0040] When the foam storage and proportionally mixing device according to the present invention operates, that is, when the foam fire extinguisher system is activated, extinguishing water having a predetermined water pressure flows into the main water supply pipe. The control unit may first send a signal to open the water intake valve 3 and the liquid outlet valve 4 . The extinguishing water is divided into two portions after entering the water supply pipe 8 . One portion of the water flows into the pressure foam tank 1 , and forces the foam liquid pre-stored in the rubber diaphragm of the pressure foam tank 1 into the proportional mixer 2 through the liquid outlet valve (electric control valve or one way valve) 4 and the porous plate 6 , while the other portion of the water flows directly from the water supply pipe 8 into the proportional mixer 2 through the nozzle of the proportional mixer 2 . Here the two parts of liquid are mixed to produce a mixed foam liquid in a predetermined proportion of mixture for subsequent output.
[0041] When the control unit detects that the output from the foam tank 1 to the proportional mixer 2 reaches a predetermined value, for example a flow meter detects that the foam liquid stored in the pressure foam tank 1 has been output to a certain extent, or it is otherwise detected that the foam liquid has been output for a certain time, the control unit sends a electric signal to close the water intake valve 3 and the liquid outlet valve 4 such that the output of the foam liquid from the foam tank 1 to the proportional mixer 2 is stopped, and to open the water intake valve 3 a and the liquid outlet valve 4 a . The timing of the opening may be before, after or at the same as that of the closing. After the water intake valve 3 is closed and the water intake valve 3 a is opened, the water which previously flows into the water supply pipe 8 is diverted into the water supply pipe 8 a through the water intake valve 3 a . Similar to the aforesaid description, the water is divided into two portions. One portion of the water flows into the pressure foam tank 1 a to force the foam liquid pre-stored in the rubber diaphragm of the pressure foam tank 1 a into the proportional mixer 2 a through the liquid outlet valve (electric control valve or one way valve) 4 a and the porous plate 6 a , while the other portion of the water flows directly from the water supply pipe 8 a into the proportional mixer through the nozzle of the proportional mixer 2 a , such that a mixed foam liquid with a predetermined proportion of mixture is produced and then output. At the time when the foam liquid stored in the pressure foam tank 1 a is forced to be output into the proportional mixer 2 a , the control unit sends a signal to open the liquid supply valves 10 , air outlet valves 11 and water outlet valve 7 such that the foam liquid in the foam storage tank 12 is injected into the pressure foam tank 1 , while the air in the rubber diaphragm may be discharged through the air outlet valve 11 , and the water in the pressure foam tank may be discharged through the water outlet valve 7 . When the flow meter (not shown) detects that the foam liquid stored in the pressure foam tank la has been output to certain extent or for a certain time, the control unit sends a electric signal to close the water intake valve 3 a and the liquid outlet valve 4 a , and to open the water intake valve 3 and the liquid outlet valve 4 . The timing of the opening may be before, after or at the same as that of the closing. Thus, the aforesaid process of output and replenishment of the foam liquid in each of the pressure foam tanks repeats, and the pressure foam tanks are replenished alternatively with the foam liquid, while the pressure foam tank alternatively outputs the foam liquid to its corresponding proportional mixer, such that the mixed foam liquid is supplied continuously from the proportional mixers for the fire extinguisher system for extinguishing fire.
[0042] Obviously, the normal pressure foam storage tank described in the present invention may be one tank, and may also be a group of tanks or groups of tanks formed by a plurality tanks connected in parallel. According to a particular requirement or circumstance, the replenishment of liquid from groups or a plurality of foam storage tanks to a plurality of pressure foam tank may be implemented on one-to-one basis. Alternatively, the liquid may be replenished in sequence of the tanks or groups of tanks. That is, after the foam liquid in a tank or a group of tanks is used up, next tank or next group of tanks is sequentially used to replenish the liquid.
[0043] The alternate foam storage and proportionally mixing device may be used in various foam fire extinguisher system, such as open-type foam fire extinguisher system, enclosed-type foam fire extinguisher system, low expansion foam fire extinguisher system, medium expansion foam fire extinguisher system and high expansion foam fire extinguisher system, etc.
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The present invention relates to an alternate foam storage and proportionally mixing device, comprising at lest one normal pressure foam storage tank, at least two pressure foam tanks, at least one proportional mixer and a control unit, wherein the foam storage tank is used to store foam liquid and alternatively output the foam liquid to the at least two pressure foam tanks, and the at least two pressure foam tanks alternatively output the foam liquid to the at least one proportional mixer, and the at least one proportional mixer outputs mixed foam liquid. The alternate foam storage and proportionally mixing device has the advantages of accurately mixing foam liquid, simple structure, and rubber diaphragm that tends not to be broken. As a major component of the present invention, the pressure foam tank may be produced in a standard manner, thereby greatly reducing production cycle and cost.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 61/273,662 filed Aug. 7, 2009, and entitled “An Apparatus and Method to Utilize the Space Under a Deck for Storage,” the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to storage and, more particularly, to an apparatus and method for utilizing space under a deck to provide storage.
[0004] 2. Description of Related Art
[0005] Generally, storage space in a home is limited. Closets, basements and garages seem to not provide enough storage space for homeowners. It is, therefore, desirable to overcome the above problems and others by providing increased storage for homeowners utilizing the existing infrastructure of the home.
SUMMARY OF THE INVENTION
[0006] To overcome the deficiencies of the prior art, what is needed, and has not heretofore been developed, is an apparatus and method to utilize previously unused or underused space underneath a deck for storage purposes. Generally, the present invention relates to an apparatus designed to allow the space under a deck to be used for storage. The apparatus includes components that allow it to be suspended from various parts of the deck structure. The general design of the apparatus includes anchoring components (AC), vertical components (VC) and a storage component (SC). An AC is designed to serve as the main point of securement between the deck and the apparatus. The various embodiments of an AC have been designed to allow the apparatus to interact with various parts of the deck structure. It is to be understood that the term “interact”, “interaction”, and forms thereof relate to connectivity, securement, attachment, fastening, movement, and the like between the indicated components of the various embodiments discussed herein. It is to be understood that the term “deck”, in the generic sense is to encompass the decking planks and the joists supporting the planks.
[0007] In one embodiment of the apparatus, an AC is designed to interact with the decking surface. The design of an AC in this embodiment is such that part, or all, of the load of the apparatus is carried by the decking. A VC or VCs then extends from an AC to the space below the decking to connect to a storage component. Various embodiments of this AC are described herein.
[0008] In another embodiment an AC is a substantially flat element that straddles the space between two deck boards through which a VC may project. An AC may also be constructed to interact with a single deck plank in which case a VC or VCs may project downward through the spaces on either side of the plank. A wedge-like device may be used to tap into the space between dank planks to allow a portion of an AC or a VC to pass through. The shape and size of an AC may be variable. The number of AC's per apparatus is variable. In one embodiment an AC and VC is be positioned to interact with each of the four corners of a rectangular or square SC. An AC may be in continuity with other AC's either across decking planks or within the space between decking places. An AC may be secured to the decking in a variety of fashions including nails, screws, glue, etc. Alternatively, an embodiment is described wherein an underside component (UC) is utilized. A UC is designed to be placed on a VC on the underside of the decking. When displaced upward, a UC may provide a counterforce against an AC on the top of the same decking plank thus securing the AC and VC in place.
[0009] In yet another embodiment of an AC interacting with the deck planks, a hole is drilled into a plank with a specialized drill bit (SDB). This SDB creates a two-level beveled hole in a plank. A specialized AC may be used in this setting that allows the AC to rest on the inner bevel of the drilled hole while maintaining a flat profile on the top of the deck. A VC protrudes through the entire hole and below the decking.
[0010] Several variations of VCs are described to function with ACs on the deck planking. A VC or VCs may be integrated with an AC or ACs at the time of production. Alternatively, a VC or VCs may be attached to an AC or ACs by the user. The dimensions of a VC may be variable. The VC is designed to attach to an AC on the decking and project through the space between two decking planks. There may be one VC per AC or a VC may be constructed to span two or more ACs within the same decking space.
[0011] One embodiment allows for a VC to rotate with respect to an AC allowing for the VC, and thus the storage component, to be oriented in different directions with respect to the decking.
[0012] An AC and two VCs may be an integral unit forming an upside down U-shaped element. In one such embodiment of an integrated AC and VCs, the AC and/or VCs may be constructed in a non-rigid fashion resulting in a belt-like component. The belt-like AC may be constructed of various lengths and may therefore span various number of deck planks. In this embodiment the belt-like construction of the AC may be contiguous with one or more vertical components creating a belt-like combined anchoring/vertical component (BCAVC). A BCAVC may extend from a location on the storage component, over several decking planks, and attach to an opposing location on the storage component. In this version a BCAVC may be utilized at the front and a BCAVC may be utilized at the back of a square or rectangular storage component. Alternatively, a BCAVC may extend from a location on the storage component, over a single deck plank, and then attach to the storage component at location near its origin. In this version a BCAVC may be utilized at each corner of a square or rectangular storage component.
[0013] A VC may be constructed with functionality that allows it to be displaced upward toward the deck and downward away from the deck. Either a telescoping VC or a scissoring VC may allow an SC to move toward or away from the deck above. In this embodiment, the VC may need to be attached to a portion of the AC that projects below the decking. A handle may be utilized to facilitate movement of an SC.
[0014] A VC may be provided as a mechanism of attachment for a storage component (SC). Various embodiments of attachment are proposed including pins on the SC which may interact with either an opening or a hook on a VC. A VC may have openings that allow for a horizontal shelf to be positioned on which an SC may be placed. Alternatively, VCs may be reversibly attached to a platform on which an SC may be placed. The platform may have a sliding functionality that allows for an SC to be moved back and forth. Yet another embodiment describes suspension belts that span VCs and provide a surface on which an SC is placed. A horizontal attachment component (HAC) may be utilized for attachment of VCs to an SC. The HAC may interact with two or more VCs and provide a larger surface area for attachment to a SC. The attachment of a VC or HAC to an SC may be secured using mechanisms such as screws or bolts.
[0015] The apparatus may be designed to interact with the joists. The design of an AC in this embodiment is such that part, or all, of the load of the apparatus is carried by the joists. In this embodiment of the apparatus, a joist anchoring component (JAC) is utilized. A JAC is designed to be placed within the space between decking planks and rest on the joists that are perpendicular to the planks. In one version, a JAC may be an inverted U-shaped element. The base of the inverted U may rest on a joist between decking planks while the longer arms of the U may project below the deck to interact with a storage component, thus functioning as an integrated AC and VC. To create a more stable JAC, two or more JACs may be connected to create a connecting joist anchoring component (CJAC). In this version of a CJAC, elements may link together two or more JACs. These connecting elements may be constructed to allow them to pass through the space between the decking planks. The long arm of a U-shaped JAC or CJAC may be constructed with any of the previously described elements of VCs that allow connection with an SC.
[0016] In another embodiment of the apparatus that utilizes joists as an anchoring point, a wire-like anchoring component (WLAC) may be used. A WLAC may include a wire or rope-like element that may attach to a storage component. The WLAC may then pass upward through the space between two decking planks and then rest on one or more joists while running perpendicular to the joists. The WLAC may then pass downward and reattach to the storage component. In this embodiment, the WLAC may essentially function as an integrated AC and VCs. The wire-like nature of this AC may permit the user to control the displacement of the storage component with respect to the deck. A WLAC guide may be utilized. The guide may be placed on a joist between two deck planks. The guide may have a low profile may remain below the level of the decking and provide a better surface on which a WLAC may rest and move. A WLAC or WLACs may be constructed with handles. This may allow the user to better control the movement of a WLAC or WLACs.
[0017] The apparatus may be designed to interact with the beams. The design of an AC in this embodiment is such that part, or all, of the load of the apparatus is carried by the beams. In this embodiment of the apparatus, a beam anchoring component (BAC) may be utilized. In one embodiment, a BAC may include a horizontal element that may span the distance between two beams. At either end of this horizontal element, a component may be present to allow the BAC to rest on a beam and also prevent displacement of the BAC. The horizontal element may be constructed with components that allow an SC to be directly suspended from the element. In one such design, rail-like ledges may span two or more BACs and a T-shaped element on an SC may interact with the ledge. The SC may be moveable along the rail-like ledge in this embodiment.
[0018] A BAC may also be constructed so that no horizontal element is utilized. In these embodiments, a BAC may be designed in an upside down square J-shaped fashion. The shorter arm of the J-shaped BAC may be placed on the beam. The longer arm of the J-shaped BAC may then project away from the deck and allow for a point of attachment for a SC, thus creating an integrated AC and VC. The long arm of a J-shaped BAC may be constructed with any of the previously described elements of VCs that allow interaction with an SC. Alternatively, the long arm of the J-shaped BAC may interact with various elements such as shelves and platforms that then provide a mechanism of interaction with an SC.
[0019] In some embodiments, the apparatus may be incorporated into the initial construction of the deck. In this embodiment, specialized deck planking, joists or beams may be utilized, wherein vertical components have been integrated into the plank, joist or beam. These same components may also be utilized in an embodiment where original decking planks are removed and replaced with an element where a specialized decking plank with integrated vertical components is utilized. Various attachment mechanisms may then be utilized to interact with an SC.
[0020] Depending on the height of the deck, it may be useful for the storage component to move up and down and toward and away from the deck. This functionality may be achieved by utilizing specialized vertical components. In one embodiment a VC may be constructed with telescoping elements, wherein the length of a VC, and thus the distance of a storage component from the deck, is modifiable as elements of a VC are either internalized into or externalized out of successive VC elements. Alternatively, the same functionality may be achieved by utilizing a scissoring mechanism.
[0021] In one embodiment, the present invention includes an apparatus for utilizing space under a deck for storage, wherein the apparatus includes (a) a first securing element having a first and second portion, wherein the first portion is formed to engage the deck and extends downward therefrom toward the ground; and (b) a storage element sized to be received beneath the deck, wherein the second portion of the first securing element is secured to the storage element. The apparatus may include a second securing element having a first and second portion, wherein the first portion is formed to engage the deck and extends downward therefrom toward the ground, wherein the second portion of the first securing element is secured to one portion of the storage element and the second portion of the second securing element is secured to another portion of the storage element. One portion of the storage element may be defined on one side of the storage element and the another portion of the storage element may be defined on an opposite side of the storage element. The first portion may include a first and second elongate member, wherein the first elongate member is substantially perpendicular to the second elongate member, and wherein the second elongate member is sized to be received in a space defined between two planks of the deck. The first and second securing elements may be sized to be received through a first and second hole defined within a respective first and second plank of the deck. The respective first portions of the first and second securing elements may be formed to engage two sides substantially perpendicular to each other of respective joists of the deck. The respective first portion of the first and second securing elements may be secured to the respective joists via fasteners (e.g., nut/bolts, screws). The first and second securing elements may be extendable in a direction perpendicular to the deck. The storage element may be movable in a direction parallel to the deck. The storage element may be substantially planar and may be connected to the respective second portions of the first and second securing elements. The storage element may include an enclosure having at least one open end.
[0022] In another embodiment, the present invention includes an apparatus for utilizing space under a deck for storage, wherein the apparatus includes (a) a first and second flexible wire sized to be received in respective spaces defined between a first set of planks and a second set of planks of the deck, wherein the first and second wires include respective first and second ends; and (b) a storage element sized to be received beneath the deck, wherein the first and second ends of the first wire are secured to a first set of opposite ends of the storage element, and wherein the first and second ends of the second wire are secured to a second set of opposite ends of the storage element. The apparatus may further include a first set and second set of anchoring guides, wherein the first and second anchoring guides are sized to be securely received onto a respective first and second joist of the deck. Each of the anchoring guides may include a channel at least as wide as the width of the first or second wire. The storage element may include an enclosure having at least one open end.
[0023] In another embodiment, the present invention includes a method for utilizing space under a deck for storage, wherein the method includes the steps of (a) lowering a first securing element through a space defined between a first and second plank of the deck, wherein a first portion of the first securing element is secured against at least the first or second plank; (b) lowering a second securing element through a space defined between a third and fourth plank of the deck, wherein a first portion of the second securing element is secured against at least the third or fourth plank; and (c) securing a storage element to respective second portions of the first and second securing elements, wherein the storage element is situated beneath the deck. The storage element may include an enclosure having at least one open end.
[0024] These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a perspective view of a deck anchoring apparatus according to a first embodiment;
[0026] FIG. 2 is a perspective view of a deck anchoring apparatus according to a second embodiment;
[0027] FIG. 3 is a perspective view of a deck anchoring apparatus according to a third embodiment;
[0028] FIG. 4 is a perspective view of a deck anchoring apparatus according to a fourth embodiment;
[0029] FIG. 5 is a perspective view of anchoring components used in the embodiments shown in FIGS. 1-4 ;
[0030] FIG. 6 is a perspective view of a horizontal attachment and sliding platform used in the embodiments shown in FIGS. 3 and 4 , respectively;
[0031] FIG. 7 is a perspective view of anchoring embodiments according to a first embodiment;
[0032] FIG. 8 is a perspective view of a storage component attachment mechanism according to a first embodiment;
[0033] FIG. 9 is a perspective view of a storage component attachment mechanism according to a second embodiment;
[0034] FIG. 10 is a perspective view of a storage component suspension mechanism according to a first embodiment;
[0035] FIG. 11 is a perspective view of a storage component suspension mechanism according to a second embodiment;
[0036] FIG. 12 is a perspective view of a deck securement mechanism according to a first embodiment;
[0037] FIG. 13 is a perspective view of a deck securement mechanism according to a second embodiment;
[0038] FIG. 14 is a perspective view of a deck spacing component;
[0039] FIG. 15 is a perspective view of a drill bit for creating a beveled hole in decking;
[0040] FIG. 16 is a perspective view of an anchoring component for use with the beveled hole of FIG. 15 ;
[0041] FIG. 17 is a perspective view of a deck anchoring apparatus according to a fifth embodiment;
[0042] FIG. 18 is a perspective view of a deck anchoring apparatus according to a sixth embodiment;
[0043] FIG. 19 is a perspective view of a deck anchoring apparatus according to a seventh embodiment;
[0044] FIG. 20 is a perspective view of a deck anchoring apparatus according to a seventh embodiment;
[0045] FIG. 21 is a perspective view of an adaptive anchoring element according to a first embodiment for use in the deck anchoring apparatus of FIG. 20 ;
[0046] FIG. 22 is a perspective view of a deck anchoring apparatus according to an eighth embodiment;
[0047] FIG. 23 is a perspective view of a deck anchoring apparatus according to a ninth embodiment;
[0048] FIG. 24 is blown-up perspective view of the deck anchoring apparatus of FIG. 23 ;
[0049] FIG. 25 is a perspective view of a deck anchoring apparatus according to a tenth embodiment;
[0050] FIG. 26 is a perspective view of a deck anchoring apparatus according to an eleventh embodiment;
[0051] FIG. 27 is a perspective view of a deck anchoring apparatus according to a twelfth embodiment;
[0052] FIG. 28 is a blown-up perspective view of the deck anchoring apparatus of FIG. 27 ;
[0053] FIG. 29 is a perspective view of a deck anchoring apparatus according to a thirteenth embodiment;
[0054] FIG. 30 is a perspective view of a deck anchoring apparatus according to a fourteenth embodiment;
[0055] FIG. 31 is a blown-up perspective view of the deck anchoring apparatus of FIG. 30 ;
[0056] FIG. 32 is a perspective view of a deck anchoring apparatus according to a fifteenth embodiment;
[0057] FIG. 33 is a perspective view of a deck anchoring apparatus according to a sixteenth embodiment;
[0058] FIG. 34 is a blown-up perspective view of the deck anchoring apparatus of FIG. 33 ;
[0059] FIG. 35 is a blown-up perspective view of the deck anchoring apparatus of FIG. 33 having further securing means;
[0060] FIG. 36 is a perspective view of a deck anchoring apparatus according to a seventeenth embodiment;
[0061] FIG. 37 is a perspective view of a deck anchoring apparatus according to an eighteenth embodiment;
[0062] FIG. 38 is a perspective view of a deck anchoring apparatus according to a nineteenth embodiment;
[0063] FIG. 39 is a blown-up perspective view of the deck anchoring apparatus of FIG. 38 ;
[0064] FIG. 40 is a perspective view of a deck anchoring apparatus according to a twentieth embodiment;
[0065] FIG. 41 is a perspective view of a deck anchoring apparatus according to a twenty-first embodiment; and
[0066] FIG. 42 is a perspective view of a deck anchoring apparatus according to a twenty-second embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0067] The present invention will now be described with reference to the accompanying figures. For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom” and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is to be understood that the specific apparatus illustrated in the attached figures and described in the following specification is simply an exemplary embodiment of the present invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.
[0068] In all of the embodiments described above the apparatus may be constructed with functionality that prevents the storage components from being filled with material that may place excessive weight on the deck structure. This functionality may be achieved via a “break-away” design built into any of the apparatus' components or interactions. For example with excessive weight in the storage component a vertical component may be designed to separate from a horizontal component, a horizontal component may be designed to separate from an attachment pin or an attachment pin may be designed to separate from a storage component. Alternatively, vertical components may be constructed with failure seams that may separate at a predetermined load. Also, the floor of a storage component may also be constructed to break away when a certain load is placed in the storage component. One possible mechanism for this breakaway functionality may be the utilization of perforation seams that may impart a point of separation that may be designed to fail and separate at a predetermined weight load.
[0069] FIG. 1 depicts an embodiment of the apparatus in which the anchoring component is on the decking. The deck in the figure includes decking ( 100 ) joists ( 105 ) beams ( 110 ) and posts ( 115 ). In this embodiment, anchoring components (AC) ( 120 ) are designed to rest on the deck planks ( 100 ). The shape and size of the AC may be variable. The ACs are shown as interacting with vertical components (VC) ( 125 ). An AC and VC may be integrated at the time of manufacturing. Alternatively, an AC and a VC may be reversibly or irreversibly assembled at the time of need. A VC is designed to pass through the narrow space between deck planks ( 100 ) and interact with a storage component (SC) ( 130 ). This interaction may occur utilizing several embodiments. In the figure a VC may interact with an SC via various mechanisms including bolts or screws. The VC may be “L”-shaped so that an SC rests on a portion of a VC to provide a horizontal surface on which a SC may rest providing more support. In another embodiment a SC may be oriented perpendicularly to the decking planks ( 100 ).
[0070] FIG. 2 depicts an embodiment of the apparatus in which the anchoring component is on the decking and anchoring components are connected. In this figure two or more VCs are shown interacting with the same anchoring component. This connecting anchoring component (CAC) ( 135 ) may serve to distribute the load of the apparatus over a larger surface of the deck planks ( 100 ).
[0071] FIG. 3 depicts an embodiment of the apparatus in which a specialized component may be utilized to attach vertical components to a storage component. In the figure, a horizontal anchoring component (HAC) ( 140 ) is shown prior to its attachment to vertical components. An HAC may interact with two or more VCs. The method of attachment of an HAC to VCs is variable. In one embodiment, an HAC may simply be attached with bolts or a similar mechanism. An HAC may have a horizontal component, like an “L”-shaped VC, so that a ledge may be created to provide additional support for a storage component. An HAC may interact with a storage component via various mechanisms. In one embodiment, bolts or screws or similar mechanisms may be utilized.
[0072] FIG. 4 depicts an embodiment of the apparatus in which a platform is utilized. In the figure a sliding platform (SP) ( 145 ) is shown as interacting with vertical components. An SP may interact with a variable number of VCs. An SP may interact with VC via various mechanisms. In a one embodiment of the apparatus, an SP may be secured to VCs using bolts or similar techniques. An SP is designed to allow a user to move a storage component from a position under the deck to a position that is more accessible. In the figure, the SP may include two components. One component is designed to interact with VCs. A second component is shown on top of the first and may slide on top of the first component. This sliding action may be achieved utilizing various mechanisms. In one embodiment, a series of rollers may be placed on the bottom (non-moveable) component. This may allow the top component, and thus the SC to move. Alternatively, wheels may be placed on the upper component that may move within tracks on the lower component. A handle ( 150 ) may be utilized to facilitate movement of the SC. An SC may be secured to a SP utilizing various mechanisms including bolts.
[0073] FIG. 5 depicts embodiments of anchoring components and vertical components. On the left an anchoring component (AC) ( 120 ) is shown interacting with a vertical component (VC) ( 125 ). An AC may interact with a VC either reversible or irreversible manner. A VC may be placed through the space between two deck planks ( 100 ) bringing the AC in contact with the planking ( 100 ). The end of a VC opposite the AC may interact with a storage component (not shown). On the right in the figure is an embodiment of an AC wherein an AC interacts with two or more VCs. This connecting anchoring component (CAC) ( 135 ) provides a greater area of contact between the deck planking ( 100 ) and the apparatus. As in the other embodiment the CAC may connect either in a reversible or irreversible manner with VCs. Also as in the other embodiment the VCs may be placed through the space between two deck planks ( 100 ) allowing for a VC to interact with a storage component under the deck. In both embodiments screw holes ( 155 ) may be utilized. The screw holes may allow for the user to more securely place the apparatus on the deck. In one embodiment of an AC the surface of the AC that rests on the deck planking ( 100 ) may be constructed with nail-like points. The user may then hammer the AC to the planks ( 100 ).
[0074] FIG. 6 depicts embodiments of components that may allow storage components to interact with the other elements of the apparatus. In the upper left is a figure of a sliding platform (SP) ( 145 ). An SP may provide a method of interacting with a storage component. In the figure, the SP is shown as having two elements. One element interacts with vertical components. The second element is designed to interact with the first element in a fashion that may allow it to slide. The sliding mechanism may occur via various mechanisms including rollers and wheels on tracks. The storage component may be placed on the moveable element allowing the user to move the storage component out from under the deck for access and back under the deck for storage. An SP may connect to vertical components (VC). An SP may interact with VCs in either a reversible or irreversible manner. In the version wherein an SP attaches reversibly to VCs this attachment may occur either before or after a VC is placed through the deck planks ( 100 ). In the version wherein an SP attaches irreversibly to VCs the SP-VCs element may then be placed upward through the deck planks ( 100 ) at which time ACs may be attached. The SP-VC may be connected to any of the ACs described. In the lower right is a figure of a horizontal attachment component (HAC) ( 140 ). An HAC may extend between and attach to vertical components (VC). An HAC may attach to two or more VCs. An HAC may attach to VCs either prior to or after the VCs have been placed through the space between the deck planks ( 100 ). The attachment of an HAC to VCs may occur via various mechanisms. In one embodiment, an HAC may be simply bolted to VCs. Alternatively, an HAC may be placed into slots on the VC. Also, a variety of hooks or latches may be utilized. The use of an HAC may provide additional contact area for a storage component. In the figure, screw holes ( 155 ) are shown that may allow a storage component to be attached to the other elements of the apparatus in a more secure fashion.
[0075] FIG. 7 depicts embodiments of anchoring components. In the left of the figure an anchoring component (AC) ( 120 ) is shown as spanning a single deck plank ( 100 ). In this embodiment the AC rests on a single deck plank ( 100 ). On either side of the plank ( 100 ) the AC may either be in continuity with, or attach to, a vertical component (VC) ( 125 ) in the space on either side of the plank ( 100 ) on which the AC rests. In the embodiment wherein this AC attaches to a VC the VC may attach at the level of the deck. Alternatively, the AC may be constructed with elements that pass through the space between the planks ( 100 ) allowing for attachment below the level of the deck. In the figure on the right, an AC is shown as spanning two deck planks ( 100 ). In this embodiment the AC may either be in continuity with, or attach to, a VC in the space between the planks ( 100 ) on which the AC rests. As in the AC embodiment on the left a VC may attach at the level of the deck. Alternatively, the AC may be constructed with elements that pass through the space between the planks ( 100 ) allowing for attachment below the level of the deck. The figure shows that either AC may be constructed with holes that allow screws to be utilized to secure an AC to the deck planks ( 100 ).
[0076] FIG. 8 depicts an embodiment of a mechanism of attachment of a storage component to vertical components. In the figure, a storage component (SC) ( 130 ) is shown. Attachment pins (AP) ( 160 ) may be positioned at various locations on an SC. An AP may be an integral component of an SC as shown on the front of the SC. Alternatively, an AP may attach in a reversible manner using various mechanisms such as a screw. An AP is one mechanism by which an SC may interact with vertical components (VC) ( 125 ). In the figure, vertical components are shown that may include vertical component openings (VCO) ( 165 ). A VCO may be created as various designs. In the figure, a VCO may include an upper larger opening that is in continuity with a smaller lower opening. In this design the larger opening may provide easier access for an attachment pin into the opening. The size of the upper opening may allow the pin to move within the upper opening thus allowing movement of the and thus facilitating the placement of other APs into openings. Once a pin is in opening, the SC may be positioned so that the SC moves into the smaller opening. The size of the smaller opening is such that the AP, and thus the SC, may be less mobile. An SC may be elevated, thus moving APs out of the lower smaller opening and into the larger upper opening which may facilitate removing the APs from the VC. A VC may include pliable material. This may allow the VC to be moved toward and away from the AP and SC thus facilitating the placement of an AC into an opening. VCOs may be positioned anywhere on a VC. In one embodiment, a series of VCOs are present arranged along the length of a VC. This arrangement may allow the user to change the position of the SC with respect to a VC.
[0077] FIG. 9 depicts an embodiment of a mechanism of attachment of a storage component to vertical components. In the figure, a storage component (SC) ( 130 ) is shown. Attachment pins (AP) ( 160 ) are positioned at various locations on an SC. An AP may be an integral component of an SC as shown on the front of the SC. Alternatively, an AP may attach in a reversible manner using various mechanisms such as a screw. An AP is one mechanism by which an SC may interact with vertical components (VC) ( 125 ). In the figure, vertical components are shown that include vertical component hooks (VCH) ( 170 ). A VCH may be created as various designs. In the figure, an embodiment of a VCH is shown having a substantially horizontal element and a substantially vertical element. In this design the horizontal element may provide a surface on which an AP may be positioned. The dimensions of this horizontal element may be variable. A VCH may also include a vertical element. A vertical element may be positioned at the end of a horizontal element. The position of this vertical element may prevent movement of an AP on the horizontal element. The dimensions of the horizontal element and the vertical element may be variable and may determine the mobility of an AP, and thus an SC, in relationship to the VCs. A VC may include pliable material. This may allow the VC to be moved toward and away from the AP and SC thus facilitating the placement of an AC into an opening. VCHs may be positioned anywhere on a VC. In one embodiment, a series of VCHs are arranged along the length of a VC. This arrangement may allow the user to change the position of the SC with respect to a VC. A VCH may be positioned on the front or back of a VC. This embodiment of attachment may also provide a mechanism that may allow a SC to be oriented perpendicular to the decking planks ( 100 ).
[0078] FIG. 10 depicts an embodiment of a mechanism of attachment of a storage component to vertical components. In the figure, specialized vertical components are shown that include vertical component openings (VCO) ( 165 ). In this figure of the apparatus, a VCO is substantially rectangular in design and intended to accommodate a suspension shelf (SS) ( 175 ). In one embodiment of the apparatus, four vertical components may be utilized to interact with two SSs. A storage component (SC) may then be placed on the two SSs. The bottom of an SC may be created with grooves that may be of dimensions similar to that of an SS. This may allow the groove of an SC to be placed on an SS and limit the motion of the with respect to the SS.
[0079] FIG. 11 depicts an embodiment of a mechanism of attachment of a storage component to vertical components. In the figure, two vertical components (VC) ( 125 ) are shown. A suspension belt (SB) ( 180 ) is shown spanning the two VCs. An SB may be attached to one VC prior to placement of the VC onto deck. In this embodiment the free end of the SB may then be passed through the spacing between two deck planks ( 100 ) in a manner similar to a VC. The SB may then be attached to the second VC and pulled taught to provide a surface on which a storage component may rest. The attachment of an SB to a second VC may occur utilizing various mechanisms. In one embodiment, a mechanism similar to a belt and buckle may be utilized.
[0080] FIG. 12 depicts an embodiment of mechanisms that may be utilized to create a more secure interaction between the deck and the apparatus. Two embodiments of components of the apparatus that utilize an underside component (UC) ( 185 ) are shown. An anchoring component (AC) ( 120 ) and a vertical component (VC) ( 125 ) are shown. The AC may be resting on the top of the deck surface and the VC may be projecting between two deck planks ( 100 ) into the space below the deck. A decking plank ( 100 ) may thus be present on either side of the vertical component in what is labeled as the decking space (DS) ( 210 ). In both of the embodiments shown a UC has been placed on the VC. The UC may be constructed as an element that may be assembled on the VC. In one embodiment, the UC may include two, mostly symmetrical pieces that may be bolted together around a VC. Alternatively, a UC may be a component that needs no assembly by the user. In this version the opening in a UC may need to be placed over a VC prior to attaching a storage component to a VC. In either embodiment a UC may be movable up (toward the underside of the deck) and down (away from the underside of the deck) on a VC. When the components of the apparatus are in place, the user may move a UC upward to the underside of the decking. Upward pressure of a UC may tightly associate the UC, the intervening planking and the AC. In the figure on the left, the UC may be secured in position via a screw securing mechanism (SSM) ( 190 ). The user may turn the SSM which may advance an element into contact with a VC thus preventing the UC from moving away from the underside of the deck plank ( 100 ). In the figure on the right of the figure, the UC may be secured on position via a lever securing mechanism (LSM) ( 195 ). For clarity, the figure shows an LSM oriented upward. However, in the functional version of the apparatus the LSM may be oriented and positioned in manner similar to the SSM. The user may deploy the LSM toward or away from the apparatus which may advance a dynamic bumper (DB) ( 200 ) into contact with a VC thus preventing the UC from moving away from the underside of the deck plank ( 100 ). A UC may be secured to the underside of the deck planking ( 100 ) via screws (holes visible on UC on right). Bumpers ( 205 ) may be utilized on a UC at the surface that may interact with the underside of the decking.
[0081] FIG. 13 depicts another embodiment of mechanisms that may be utilized to create a more secure interaction between the deck and the apparatus. The figure on the left shows an underside component (UC) ( 185 ). The figure on the right shows a UC that has been placed on a vertical component (VC) ( 125 ). The UC may be assembled on the VC. Alternatively, a UC may be placed onto an end of a VC via the central opening. For clarity, no decking planks are shown in the figure. The planking may be in the area labeled as decking space (DS) ( 210 ). Screw holes are shown on the various components of the apparatus including the anchoring component and the underside component with screws or bolts ( 215 ). The number and location of the screw holes may be variable and may be positioned to optimize functionality.
[0082] FIG. 14 depicts an embodiment of a component that may be utilized to facilitate the placement of a vertical component between the decking planks. Decking planks ( 100 ) are shown in the figure. It is anticipated that the space between planks ( 100 ) may not be of a sufficient dimension to allow for the placement of a vertical component between. It thus may be necessary to modify the space to accommodate the placement of a VC. In the figure, a spacer ( 220 ) is shown as being placed in the space between two planks ( 100 ). A spacer may be designed various shapes and sizes. In one embodiment, a spacer is a triangular wedge-like element. The narrow end may be placed into a narrow space between two planks ( 100 ). As the spacer is advanced between the planks ( 100 ) a wider part of the spacer is advanced between the planks ( 100 ) thus widening the space. In the figure, the wide and flat top of the spacer may facilitate the use of a hammer or similar tool to assist in advancing the spacer.
[0083] FIG. 15 depicts a component of the apparatus that may allow for the modification of the decking to accommodate a specialized anchoring component. In the figure, deck planks ( 100 ) are visible. A specialized drill bit (SDB) ( 225 ) may allow the user to create a customized opening on a deck plank ( 100 ). An SDB may be designed to fit any standard commercial drill. The customized opening may include a partial thickness opening that may create a bevel ( 230 ). This may provide a surface on which an anchoring component may rest. Within the partial thickness opening may be a hole ( 235 ) that passes through the remainder of the plank ( 100 ). This may allow a vertical component to pass through the space below where it may be attached to a storage component.
[0084] FIG. 16 depicts an embodiment of an anchoring and vertical component designed to pass through a customized hole in a deck plank ( 100 ). The figure shows decking planks ( 100 ). A specialize anchoring component (AC) ( 120 ) and vertical component (VC) ( 125 ) are shown. In one embodiment, the AC and the VC may be integrated as a single unit. Alternatively, an AC and a VC may be separate components that may be assembled at the time of need. The AC in this embodiment may be constructed with a handle ( 240 ). The handle may be constructed with swivel functionality. This may allow the handle to be placed into a recessed area of the AC allowing the AC to maintain a flat profile. In the figure, the VC passes through the previously described hole to the space below the deck. The anchoring component may rest on the bevel ( 230 ).
[0085] FIG. 17 depicts an embodiment of the apparatus that may include anchoring components that span multiple deck planks ( 100 ). In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). In the figure, the anchoring component (AC) ( 120 ) is shown as an element that spans multiple decking planks ( 100 ). In this embodiment an AC may include a rigid or non-rigid element that may rest on the top of multiple decking planks ( 100 ). At either end the AC may interact with vertical components (VC) ( 125 ). The AC and VCs may be a single element that may be placed on the deck as a single unit. Alternatively, the AC and VCs may be assembled by the user at the time of need. In one embodiment, this assembly may occur via a solid cylinder that extends parallel to the edge of one end one of the components that may be inserted into a hollow partial circumferential tube. The solid cylinder may be positioned on an extender that may be designed to project the cylinder away from the component. The hollow tube may also be positioned on an extender similar to the cylinder. The partial circumferential design of the tube may allow align with the extender of the extender of the cylinder thus allowing the tube to slide freely over the cylinder. The design may provide a hinge-like action. In the figure, the VCs are shown as interacting with a sliding platform ( 145 ). On the sliding platform a storage component ( 130 ) has been placed.
[0086] FIG. 18 depicts an embodiment of the apparatus that may include anchoring components that span multiple deck planks ( 100 ). In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). In the figure, the anchoring component (AC) ( 120 ) is shown as an element that spans multiple decking planks ( 100 ). In this embodiment an AC may include a rigid or non-rigid element that may rest on the top of multiple decking planks ( 100 ). At either end the AC may interact with vertical components (VC) ( 125 ). The AC and VCs may be a single element that may be placed on the deck as a single unit. Alternatively, the AC and VCs may be assembled by the user at the time of need. In one embodiment, this assembly may occur via a solid cylinder that extends parallel to the edge of one end one of the components that may be inserted into a hollow partial circumferential tube. The solid cylinder may be positioned on an extender that may be designed to project the cylinder away from the component. The hollow tube may also be positioned on an extender similar to the cylinder. The partial circumferential design of the tube may allow align with the extender of the extender of the cylinder thus allowing the tube to slide freely over the cylinder. The design may provide a hinge-like action. In the figure, the VCs are shown as interacting with a storage component ( 130 ).
[0087] FIG. 19 depicts an embodiment of the apparatus that utilizes a belt-like element that functions as both an anchoring component and a vertical component. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). The belt-like combined anchoring vertical component (BCAVC) ( 245 ) is shown as interacting with the storage component (SC) ( 130 ) at one position, extending upward through the space between two decking planks ( 100 ), over a plank ( 100 ), and back down below the deck to again interact with the SC. The BCAVC may allow the user to raise and lower an SC toward and away from the undersurface of the deck. A BCAVC may interact with an SC in various designs. In one embodiment an SC may be constructed with one end of a BCAVC integrated ( 250 ) at the time of construction. The other end of the BCAVC may of necessity be free so that it may be positioned through the deck plank spaces and then be secured ( 255 ) to an SC at a different location. This second point of interaction with an SC may be detachable allowing the user to move an SC as previously described. One possible mechanism of this second attachment may be a simple mechanism such as a belt buckle. Alternatively, a BCAVC may need to be attached to an SC prior to use at the point shown ( 250 ). In that the user may be able to raise and lower the SC it may be necessary to limit the movement of an SC. In the figure, a spacing element ( 260 ) is shown. This spacing element may be a part of an SC or it may be secured to the underside of the deck.
[0088] FIG. 20 depicts an embodiment of the apparatus in which specialized components are utilized to facilitate a storage component to be oriented perpendicular to the decking planks ( 100 ). In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). Anchoring components (AC) are shown in the figure, as well as vertical components (VC). A specialized anchoring-vertical adapting element (AVAE) ( 265 ) is shown inter-positioned between an AC and a VC. In one embodiment of the apparatus, an AC, AVAE and VC may be constructed as a single unit. In this embodiment a VC may be placed through the space between two deck planks ( 100 ). The AVAE may then allow a VC to rotate so that the flat aspect of a VC may be facing a storage component (SC) ( 130 ) thus allowing for more contact surface area. Alternatively, an AC, AVAE and a VC may be separate elements that need to be assembled at the time of use resulting in the same functionality.
[0089] FIG. 21 depicts an embodiment of the apparatus in which specialized components are utilized to facilitate a storage component to be oriented perpendicular to the decking planks ( 100 ). This figure is essentially a closer view of the components shown in FIG. 20 . Anchoring components (AC) are shown in the figure, as well as vertical components (VC). A specialized anchoring-vertical adapting element (AVAE) ( 265 ) is shown inter-positioned between an AC and a VC. In one embodiment of the apparatus, an AC, AVAE and VC may be constructed as a single unit. In this embodiment, a VC may be placed through the space between two deck planks ( 100 ). The AVAE may then allow a VC to rotate so that the flat aspect of a VC may be facing a storage component (SC) ( 130 ) thus allowing for more contact surface area. Alternatively, an AC, AVAE and a VC may be separate elements that need to be assembled at the time of use resulting in the same functionality.
[0090] FIG. 22 depicts an embodiment of the apparatus that facilitates the orientation of a storage component perpendicular to the decking planks ( 100 ). In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). Two vertical components (VC) ( 125 ) are shown as interacting with anchoring components (AC) ( 120 ) that are in place on the decking planks ( 100 ). Under the deck, a horizontal attachment component (HAC) ( 140 ) is shown. The HAC is constructed with two elements that may allow the HAC to interact with VCs. This interaction may be carried out via various mechanisms. In one embodiment, elements of an HAC are constructed that may be oriented to provide a surface area that may be parallel to a VC and allow for an interaction with the VC. The interaction between an HAC and a VC may be secured via bolts that may be utilized via the visible holes. An HAC may then provide a longitudinal structure providing more area for interaction with a storage component (SC) ( 130 ) that may be available via VCs.
[0091] FIG. 23 depicts an embodiment of the apparatus in which the anchoring components are placed on the joists. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). Joist anchoring components (JAC) ( 270 ) are shown in the figure. The three JACs in the back of the figure are positioned above the space between two decking planks ( 100 ). In the foreground the JACs have been positioned to rest on the joists. The limbs of a JAC that project below the deck may then provide a mechanism of interaction with a storage component (SC) ( 130 ).
[0092] FIG. 24 depicts an embodiment of the apparatus in which the anchoring components are placed on the joists. This figure essentially shows a closer view of the components of FIG. 23 . In the figure, the components of the deck are shown to include the planks ( 100 ) and joists ( 105 ). For clarity, the majority of the decking planks are not shown. Joist anchoring components (JAC) ( 270 ) are shown in the figure. The limbs of the JACS have been place into the space between two deck planks ( 100 ) and advanced to the space below the deck thus bringing the horizontal element of the JACs to contact the joists. The JAC may be secured to a joist or decking planks ( 100 ) utilizing screws or various clamps. The limbs of the JACs below the deck may the serve to provide a point of attachment for a storage component (SC) ( 130 ).
[0093] FIG. 25 depicts an embodiment of the apparatus in which the anchoring components are placed on the joists. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). For clarity, the majority of the decking planks are not shown. Joist anchoring components (JAC) ( 270 ) are shown in the figure. In this embodiment a JAC may include a series of previously described elements that have been integrated into a component that may interact with multiple joists. On the right in the figure, the JAC is situated above the deck. On the left of the figure, the limbs of the JACS have been place into the space between two deck planks ( 100 ) and advanced to the space below the deck thus bringing the horizontal element of the JACs to contact the joists. The JAC may be secured to a joist or decking planks ( 100 ) utilizing screws or various clamps. The limbs of the JACs below the deck may the serve to provide a point of attachment for a storage component (SC) ( 130 ).
[0094] FIG. 26 depicts an embodiment of the apparatus in which the anchoring components are placed on the joists. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ) and a post ( 115 ). For clarity, the majority of the decking planks are not shown. Joist anchoring components (JAC) ( 270 ) are shown in the figure. In the figure, a storage component (SC) ( 130 ) is shown as resting on a platform ( 280 ) that has been constructed with holes ( 285 ). The storage component in the figure is oriented perpendicular to the deck planking ( 100 ). This is achieved by having the SC interact with the narrower edge of the JAC rather than a SC interacting with the broader aspect of a JAC. In the figure, the JAC is constructed with posts ( 275 ) on which a platform, and thus an SC, may be placed.
[0095] FIG. 27 depicts an embodiment of the apparatus in which wire-like anchoring components are placed on the joists. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. Wire-like anchoring components (WLAC) ( 295 ) are shown. A WLAC may be utilized to suspend an SC from the deck. A WLAC may attach to one end of an SC, be positioned over one or more joists, and then re-attach to the SC. The attachment of a WLAC to an SC may be reversible at one end or both ends utilizing various mechanisms. An anchoring component guide (ACG) ( 300 ) may be positioned on the component of the deck where the WLAC rests. In the figure, the WLAC toward the right is shown in position over ACGs and joists and in between two decking planks ( 100 ) before being secured. The WLAC toward the left has been secured tightly so that the WLAC is resting on ACGs which in turn have been positioned on joists. In this arrangement the WLAC may rest below the decking within the space between two decking planks ( 100 ). A WLAC may allow the user to control the distance of an SC from the deck. This distance may A WLAC may be utilized to suspend the apparatus from other elements of a deck. It is envisioned that a WLAC may rest on the decking planks ( 100 ). In this embodiment grooves, perpendicular to the long axis of the decking planks ( 100 ), may be created in the planks to allow a WLAC to be positioned below the top surface of the decking.
[0096] FIG. 28 depicts an embodiment of the apparatus in which wire-like anchoring components are placed on the joists. In the figure, the components of the deck are shown to include the planks ( 100 ) and a joist ( 105 ). For clarity, only a single decking plank ( 100 ) is shown in the figure. A wire-like anchoring component (WLAC) ( 295 ) is shown as projecting just below the surface of a decking plan in the space between two planks ( 100 ). An anchoring component guide (ACG) ( 300 ) has been placed on a joist in the space between two planks ( 100 ). An ACG may be constructed to avoid contact of a WLAC with the edges of joist. An ACG may have a central groove to keep a WLAC aligned. In the figure, the ACG is curved. This embodiment may also assist in directing a WLAC to a position below the deck to interact with a storage component. An ACG may be secured to a joist with screws.
[0097] FIG. 29 depicts an embodiment of the apparatus in which wire-like anchoring components are placed on the joists. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. Wire-like anchoring components (WLAC) ( 295 ) are shown. A WLAC may be utilized to suspend an SC from the deck. A WLAC may attach to one end of an SC, be positioned over one or more joists, and then re-attach to the SC. The attachment of a WLAC to an SC may be reversible at one end or both ends utilizing various mechanisms. An anchoring component guide (ACG) ( 300 ) may be positioned on the component of the deck where the WLAC rests. In the figure, the SC is oriented perpendicular to the decking. A handle for the wire like anchoring component (HWLAC) ( 310 ) is shown. A HWLAC may allow a user to elevate and lower an SC. To secure an SC in a desired location, the HWLAC may attach either back on an SC or to another location on the deck.
[0098] FIG. 30 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. In this embodiment of the apparatus an SC is suspended from the deck utilizing a beam anchoring component (BAC) ( 315 ). A BAC may include a horizontal element that may span two or more beams. On each end of the horizontal element a BAC may have vertical elements that may be positioned on the side of a beam. The horizontal element of a BAC may be constructed with a telescoping feature so that the length of a BAC may be adjusted by the user. Various mechanisms may be utilized to attach an SC to a BAC.
[0099] FIG. 31 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. In the figure, the components of the deck are shown to including joists ( 105 ), beams ( 110 ) and a post ( 115 ). A BAC is shown to include the horizontal element and the vertical element. In the figure, the horizontal element of the BAC is shown resting on a beam, thus supporting the weight of the apparatus. The vertical element is shown, positioned at a right angle from the horizontal element, and thus preventing movement of the BAC.
[0100] FIG. 32 depicts an embodiment of one mechanism by which a storage component may attach to a beam anchoring component. In the figure, the components of the deck are shown to include a joist ( 105 ), beams ( 110 ) and posts ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. Beam anchoring components (BAC) ( 315 ) have been positioned. On the underside of the BACs are ledge attachment elements (LAE) ( 325 ). In the figure, an LAE is an “L”-shaped element that spans two or more BACs. An LAE and two or more BACs may be an integral unit. Alternatively, LAEs may be attached to BACs at the time of use. The figure show two LAEs oriented to form a ledge. The storage component in the figure has been modified with a “T”-attachment element (TAE) ( 320 ). A TAE may be integrated into a SC at the time of construction. Alternatively, a TAE may reversibly attach to an SC and thus assembled at the time of need. The horizontal elements of the TAE may be placed on the ledge created by the two LAEs. This may allow the SC to be suspended from the LAEs. The SC may be moveable forward and backward on the LAEs. This may be facilitated with rollers or bearings. In another embodiment of the apparatus the location of the TAE and LAEs are reversed wherein a TAE is positioned on BACs and LAEs are on an SC.
[0101] FIG. 33 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. The figure shows two components used to suspend the apparatus from beams. In this embodiment a combined beam anchoring vertical component (CBAVC) ( 330 ) is shown. A CBAVC is essentially an inverted square “J”-shaped anchoring element that may be placed on a beam. The “J” area of a CBAVC may be adjustable in size to accommodate beams of different dimensions. A CBAVC may be secured to a beam via screws or other mechanisms. Extending from the “J”-shaped anchoring element there is a vertical element extending downward. This element may provide for an area of attachment for a shelf ( 340 ) on which an SC may rest. The shelf may include vertical elements ( 335 ) that may interact with the vertical element of a CBAVC. This interact may be carried out by means of screws or bolts or various clasps.
[0102] FIG. 34 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. In the figure, the components of the deck are shown to include the joists ( 105 ), beams ( 110 ) and a post ( 115 ). A combined beam anchoring vertical component (CBAVC) ( 330 ) is shown positioned on a beam. In proximity, a shelf ( 340 ) is shown. The shelf may be constructed with vertical elements ( 335 ) which may interact with the vertical elements of a CBAVC.
[0103] FIG. 35 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. In the figure, the components of the deck are shown to include a joist ( 105 ), beams ( 110 ) and a post ( 115 ). A combined beam anchoring vertical component (CBAVC) ( 330 ) is shown as positioned on a beam. In the figure, screws or nails ( 345 ) are shown as securing the CBAVC to the beam.
[0104] FIG. 36 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. In the figure, the components of the deck are shown to include the planks ( 100 ), a joist ( 105 ), a beam ( 110 ) and a post ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. In the figure, the combined beam anchoring vertical components (CBAVCs) have attached to a sliding platform ( 145 ) allowing the SC to move back and forth. This may be facilitated with the handle ( 150 ) shown on the SC. This embodiment depicts that it is envisioned that the elements and components described are interchangeable so that various components that are utilized to suspend the apparatus from the decking structures may be interchanged with various components on which a storage component rests.
[0105] FIG. 37 depicts an embodiment of the apparatus in which the anchoring components are placed on beams. A storage component (SC) ( 130 ) is shown above a fenestrated platform (FP) ( 355 ) on which it may eventually rest. Two combined beam anchoring vertical components (CBAVC) are shown. In the right of the figure, a CBAVC is shown with holes ( 370 ). The holes may interact with a platform attachment element with pegs (PAEP) ( 360 ). In the left of the figure, a CBAVC is shown with slots ( 375 ). The slots may interact with a platform attachment element with a ledge (PAEL).
[0106] FIG. 38 depicts an embodiment of the apparatus in which vertical components are integrated into the decking planks ( 100 ). In the figure, the components of the deck are shown to include joists ( 105 ), beams ( 110 ) and posts ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. In this embodiment of the apparatus a vertical component interacts directly with a deck plank ( 100 ) eliminating the need for an anchoring component. In the figure, an integrated decking vertical component (IDVC) ( 380 ) is shown. The deck plank ( 100 ) and vertical element may be integrated at the time of manufacturing. Alternatively, the use may attach the vertical element at the time of need. An IDVC may be placed on the deck at the time of deck construction. It is also envisioned that old deck planks may be removed and replaced with an IDVC or IDVCs. An IDVC may be constructed with an interacting element ( 385 ) that provides a mechanism of interaction. In the figure, the interacting element is in the form of a rectangular ring. An SC in this embodiment may be constructed with an element that may allow for attachment to an IDVC. In the figure, the SC has been constructed with interacting hooks ( 390 ). The hooks may be placed onto the ring-like interacting elements. To facilitate this attachment an interacting hook may be placed on an interacting hook track (AHT) ( 395 ). With the opposing interacting hooks facing each other the AHTs may allow the user to place the back hooks on the rings, align the front AHT with rings and the move the front AHT toward the front hooks for a secure attachment.
[0107] FIG. 39 depicts an embodiment of the apparatus in which vertical components are integrated into decking planks ( 100 ). In the figure, the components of the deck are shown to include joists ( 105 ), beams ( 110 ) and posts ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. In this embodiment of the apparatus a vertical component interacts directly with a deck plank ( 100 ) eliminating the need for an anchoring component. In the figure, an integrated decking vertical component (IDVC) ( 380 ) is shown. The deck plank ( 100 ) and vertical element may be integrated at the time of manufacturing. Alternatively, the use may attach the vertical element at the time of need. An IDVC may be placed on the deck at the time of deck construction. It is also envisioned that old deck planks may be removed and replaced with an IDVC or IDVCs. An IDVC may be constructed with an interacting element ( 385 ) that provides a mechanism of interaction. In the figure, the interacting element is in the form of a rectangular ring. An SC in this embodiment may be constructed with an element that may allow for attachment to an IDVC. In the figure, the SC has been constructed with interacting hooks ( 390 ). The hooks may be placed onto the ring-like interacting elements. To facilitate this attachment an interacting hook may be placed on an interacting hook track (AHT) ( 395 ). With the opposing interacting hooks facing each other the AHTs may allow the user to place the back hooks on the rings, align the front AHT with rings and the move the front AHT toward the front hooks for a secure attachment. This figure depicts a view wherein the SC has been readied for attachment to an integrated decking vertical component (IDVC) ( 380 ) through its interaction with an interacting element ( 385 ). In the figure, the interacting hooks in the back have been engaged with the interacting elements on the IDVCs. The interacting hooks in the front may be engaged with the interacting elements as the interacting hooks may be moved along the interacting hook tracks.
[0108] FIG. 40 depicts an embodiment of the apparatus in which vertical components are integrated into decking planks ( 100 ). In the figure, the components of the deck are shown to include joists ( 105 ), beams ( 110 ) and posts ( 115 ). A storage component (SC) ( 130 ) is positioned underneath the deck. In this embodiment of the apparatus a vertical component interacts directly with a deck plank ( 100 ) eliminating the need for an anchoring component. In the figure, an integrated decking vertical component (IDVC) ( 380 ) is shown. The deck plank ( 100 ) and vertical element may be integrated at the time of manufacturing. Alternatively, the use may attach the vertical element at the time of need. An IDVC may be placed on the deck at the time of deck construction. It is also envisioned that old deck planks may be removed and replaced with an IDVC or IDVCs. In the figure, the IDVCs have been constructed with interacting ledge (AL) ( 400 ). An AL may be attached to an IDVC at the time of construction or at the time of need by the user. Two or more ALs may provide a surface whereon an interacting bar (AB) ( 405 ) may be placed. An AB is designed as an element that may be designed to function to provide for interaction between an SC and an AL of an IDVC. An AB may be constructed so that it is a contiguous element that is of equal length of an SC. Alternatively, an AB may be discontinuous and be present only in areas where an AB may interact with an AL.
[0109] FIG. 41 depicts an embodiment of the apparatus in which vertical components are modified to allow the storage component to move toward and away from the decking. In the figure, the components of the deck are shown to include joists ( 105 ), beams ( 110 ) and posts ( 115 ). A storage component (SC) ( 130 ) with is positioned underneath the deck resting on a sliding platform (SP) ( 145 ) with a handle ( 150 ). The SP is suspended on specialized telescoping vertical components (TVC) ( 410 ). The TVCs will allow the SP, and thus the SC, to move up (toward the undersurface of the deck) and down (away from the undersurface of the deck). The TVCs may be constructed with a locking mechanism that may allow the uses to secure an SC in a desired position.
[0110] FIG. 42 depicts an embodiment of the apparatus in which vertical components are modified to allow the storage component to move toward and away from the decking. In the figure, the components of the deck are shown to include joists ( 105 ), beams ( 110 ) and posts ( 115 ). A storage component (SC) ( 130 ) with is positioned underneath the deck resting on a sliding platform (SP) ( 145 ) with a handle ( 150 ). The SP is suspended on specialized scissoring vertical components (SVC) ( 410 ). The SVCs will allow the SP, and thus the SC, to move up (toward the undersurface of the deck) and down (away from the undersurface of the deck). The SVCs may be constructed with a locking mechanism that may allow the uses to secure an SC in a desired position. In other embodiments of the apparatus scissoring or telescoping vertical components may interact more directly with a storage component without the use of a platform. This interaction may occur in the way of pins and openings or pins and hooks as described in previous versions of the apparatus.
[0111] Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.
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An apparatus for utilizing space under a deck for storage includes (a) a first securing element having a first and second portion, wherein the first portion is formed to engage the deck and extends downward therefrom toward the ground; and (b) a storage element sized to be received beneath the deck, wherein the second portion of the first securing element is secured to the storage element. A method utilizes the claimed apparatus.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Provisional Application No. 60/288,591 filed on May 4, 2001.
FIELD OF THE INVENTION
[0002] This invention relates to the manufacture of Nanophotonic Waveguides and more particularly the separation of the individual chips on the wafer once manufacture has been completed.
BACKGROUND OF THE INVENTION
[0003] Conventionally, Integrated Circuit (IC) chips and structures are fabricated in multiple units on a single wafer using known IC chip fabrication techniques. At some stage, the individual IC chips must be separated from each other on the wafer once the manufacturing process has been completed. Presently, this is done by dicing, which involves sawing through the entire wafer at predetermined intervals. Such sawing through the various integrated circuit materials present on the wafer can cause stress and damage the formed IC chip structures.
[0004] Thus, there exists a need in the art for a final separation step in the manufacturing technique of integrated circuits that overcomes the above-described shortcomings.
SUMMARY OF THE INVENTION
[0005] The subject method overcomes the deficiency of the prior art by first etching separation streets between adjacent IC chips. The streets extend through the IC chip material to a substrate forming the base for the IC chip. The base is then sawed along the streets.
[0006] The invention accordingly comprises the features of construction, combination of elements, arrangement of parts and steps for performing the method, which will be exemplified in the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In the drawing figures, which are not to scale, and which are merely illustrative, and wherein like reference characters denote similar elements throughout the several views:
[0008] [0008]FIG. 1A is a side cross-sectional view of a layered structure which will be sectioned to become an optical waveguide;
[0009] [0009]FIG. 1B is a side cross-sectional view of the layered structured of FIG. 1A partially-sectioned by streets formed therein in accordance with the invention; and
[0010] [0010]FIG. 1C is a side cross-sectional view of the layered structure fully-sectioned by sawing in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Reference is first made to FIG. 1A which shows a wafer assembly for forming an optical waveguide as is known in the art. The waveguide as shown is representative of an IC chip as known in the art. IC chip 10 includes a base or substrate 12 formed by the wafer. A thick oxide cladding layer 14 is deposited on substrate 12 as is known in the art. A circuit element, in this embodiment a waveguide core 16 , by way of example, is formed, through processes known in the art such as PECVD depositing coupled with photolithographic etching. However, this is by way of example and other methods of forming an optical circuit, known in the art can be used in accordance with the present invention. Once core 16 is formed, a thick oxide cladding layer 18 is deposited over core 16 . Collectively, cladding layer 14 , core 16 , and cladding layer 18 are the “IC material.”
[0012] In the conventional method of manufacture, circuit 10 as shown in FIG. 1A will then be sawed so that a cutting step would cut substrate wafer 12 , thick oxide cladding layer 14 , and thick oxide cladding layer 18 putting a stress on the functional elements, namely layers 14 , 18 and core 16 as a result of the sawing.
[0013] In accordance with the present invention, as shown in FIG. 1B, streets 20 are formed between adjacent circuit structures (waveguides) 10 . Streets 20 are formed by coating the surface to be etched with a photo resist material and selectively exposing and curing the photo resist material to define regions corresponding to streets 20 to be etched. The streets are then etched through layers 14 and 18 , to substrate 12 . As a result, in this step of the process one is left with a wafer substrate 12 and a plurality of individual waveguides 10 arrayed thereon. Etching may be performed by either wet etching or dry etching of the IC materials. In a final step, substrate 12 is sawed (diced) to separate the individual IC chips 10 from each other and the wafer. As a result, there is no sawing of the individual IC structures on the wafer, as sawing is localized only to substrate 12 . In a preferred embodiment substrate 12 is formed as a silicon wafer, an easy to saw material resulting in isolated individual chips 10 as shown in FIG. 1C.
[0014] While there have been shown and described and pointed out fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit and scope of the invention. It is the intention therefore, to be limited only as indicated by the scope of the claims appended hereto.
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A method is provided for separating silica waveguides made in multiple units on a wafer at the end of fabrication. Streets are formed between adjacent waveguides by etching the IC material to a substrate. The substrate is then sawed along the streets.
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FIELD OF THE INVENTION
[0001] This invention relates generally to the field of orthodontics and, more particularly, to orthodontic brackets.
BACKGROUND OF THE INVENTION
[0002] Orthodontic brackets typically are attached to individual teeth and connected to an archwire. This assembly is commonly used to move and straighten teeth. Teeth are moved and rotated by applying forces on the bracket. Typically, rubber bands or other resilient devices have been used to apply the desired forces. This requires many visits to the orthodontist to check and replace worn out rubber bands. Another device used to move and straighten teeth is headgear. Headgear is typically wrapped around the back of the wearer's head and attached to the teeth requiring movement. This can be uncomfortable and/or unattractive for the wearer. Both methods of moving and straightening teeth require many check-ups, which are costly and are a significant factor in the cost of orthodontic treatment.
SUMMARY OF THE INVENTION
[0003] The present invention alleviates one or more of the above-noted issues by providing an orthodontic bracket assembly that can move a tooth without the need for standard elastic components. More specifically, the present invention provides an orthodontic bracket assembly comprising an orthodontic bracket and a powered actuator mounted to the bracket. The actuator can be used to provide relative movement between a tooth (or set of teeth) and another object, such as an archwire or another tooth (or set of teeth). Preferably, the actuator is a micro electromechanical system (MEMS) having a size that will not significantly interfere with the comfort of the patient.
[0004] In one embodiment, the assembly includes a rotary MEMS that is mounted to the bracket and that includes a wheel. In this embodiment, the wheel is positioned to engage the archwire so that force applied by the MEMS will result in relative movement between the tooth and the archwire. Engagement between the actuator and the archwire can be by any suitable means, such as frictional engagement (e.g., using a rubber material) or mechanical engagement (e.g., using teeth or other engaging mechanism).
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] [0005]FIG. 1 is a side view of a bracket embodying the present invention
[0006] [0006]FIG. 2 is a front view of the bracket of FIG. 1
[0007] [0007]FIG. 3 is a perspective view of a wheel coupled to a motor.
DETAILED DESCRIPTION
[0008] With reference to FIGS. 1 and 2, an orthodontic bracket assembly is illustrated according to the preferred embodiment for application to an upper tooth, although the same principles apply for brackets adapted for use with lower teeth. The bracket assembly includes a base 2 , a sliding locking member 6 for securing an archwire 8 and an actuator.
[0009] The base 2 includes a lingual portion 3 for attachment to a tooth by means of a mounting pad 4 or other suitable means. A pair of gingival tie wings 5 and a pair of occlusal tie wings 9 extend from the base in a buccal-labial direction. An archwire slot 14 extends generally horizontally across the base 2 and opens for receiving the archwire 8 .
[0010] The base 2 includes a groove 13 extending downward from the gingival tie wings 5 . The groove 13 provides an operable locking surface 15 for the sliding locking member 6 . According to the preferred embodiment, a second locking surface 16 is provided to lock the locking member 6 in an open position to allow removal and maintenance of the archwire 8 .
[0011] According to the preferred embodiment, the sliding locking member 6 is generally in the shape of a “U”. The locking member 6 curves at one end to form a generally hook-shaped catch 17 and at the opposite end a stopper 18 is attached for contacting the base 2 , thereby preventing the locking member 6 from sliding off of the base 2 in the open position. The locking member 6 is movable from a closed position (shown in solid lines in FIGS. 1 and 2) to an open position (shown in broken lines in FIG. 1). The general operation of the bracket and locking member is disclosed in more detail in U.S. patent application Ser. No. 09/327,732, which is incorporated herein by reference in its entirety.
[0012] As shown in FIGS. 1 and 2, the actuator 10 is secured to the base 2 . According to the preferred embodiment, the actuator 10 is a Micro electromechanical System (MEMS) with rotary capabilities. MEMS are powered by internal power mechanisms, the specifics of which are not the subject of the present invnetion. This embodiment is not meant to limit other types of actuators capable of achieving the same desired results, such as linear actuators capable of moving in lateral directions. The actuator 10 is coupled to a moving member in the form of a wheel 12 , and the wheel 12 contacts the surface 18 of the archwire 8 .
[0013] According to preferred embodiment shown in FIG. 3, the wheel 12 has the surface contacting the archwire 8 lined with a high friction material such as rubber 20 , thus creating friction between the two surfaces. In an alternative embodiment shown in FIG. 2, the contacting surface of the wheel 12 could have teeth that inter-lock with teeth on the surface 18 of the archwire 8 , or any other suitable arrangement whereby force can be transferred from the actuator to the archwire. The embodiments of the wheel 12 are not meant to be limiting and any suitable embodiments that achieve similar results can be used.
[0014] The actuator 10 is programmed to apply a constant or varying force to drive the wheel 12 , wherein the wheel 12 rolls against the surface 18 of the arch wire 8 . The friction that occurs between the surface of the wheel 12 and the surface 18 of the archwire 8 produces a force on the base 2 of the bracket, therefore producing a force on the tooth. The base 2 and the archwire 8 can be set up in many different orientations to exert the resulting force on the tooth in any desired direction. Alternatively, the actuator 10 could be programmed to move along the archwire at a constant or varying rate of speed.
[0015] Because the bracket 6 is self-ligating, the movement of the bracket will not be inhibited by elastic contacting the archwire 8 . The motor 10 also alleviates the need for elastic chain placement used commonly from the back first molar to the upper front tooth such as a cuspid to close a space in the middle of an upper bicuspid extract.
[0016] In summary, motorized orthodontic brackets enjoy the advantages of a programmable actuator as well as the advantages of eliminating rubber bands. The programmable actuator is advantageous over current methods such as rubber bands because the actuator can be programmed to provide a constant force on a tooth, therefore having the ability to move teeth over long distances without the need for orthodontic inspections. Rubber bands also have a tendency to break and become discolored, thereby requiring many visits to the Orthodontist for replacement.
[0017] The foregoing description of the present invention has been presented for purposes of illustration and description; furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain best modes known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.
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An orthodontic bracket assembly comprising an orthodontic bracket and a powered actuator mounted to the bracket. The actuator can be used to provide relative movement between a tooth (or set of teeth) and another object, such as an archwire or another tooth (or set of teeth). Preferably, the actuator is a micro electromechanical system (MEMS) having a size that will not significantly interfere with the comfort of the patient.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a building energy storage and conversion apparatus and particularly to an apparatus to effectively integrate various types of energy resources inside and outside a building and make optimal conversion and utilization thereof to supply energy required in the building to achieve onsite energy self-sufficiency and incorporate with other buildings in the neighborhood to balance energy demand and supply and obtain power from public power supply systems in case needed to establish a regional energy exchange mechanism to save energy and flexibly utilize the energy resources inside and outside the building.
[0003] 2. Description of the Prior Art
[0004] The energy resources of the earth have been consumed by mankind in the past one hundred years at an alarming speed. The accelerated and voracious consumption of energy resources have caused global warming and climatic change, and seriously threaten the survival of human being. Only through saving and more discreet use of energy can prevent catastrophe from falling to the mankind and keep the earth continuously running in a sustainable manner.
[0005] In order to solve the energy problems many types of renewable energies have been developed, such as solar energy, wind power, fuel cells and the like. One of typical applications is electric power systems adopted on buildings. Refer to FIG. 1 for a renewable energy conversion approach now widely adopted on buildings. It has an energy apparatus 11 to provide renewable energy (such as solar energy, hydrogen fuel, wind power or the like) and generate electric power supply. It also has a controller 14 to control a converter 13 to convert and select a building power supply system 15 to supply electric power needed. The power supply mainly includes three types: first, power from the energy apparatus 11 ; second, power from a public power supply system 12 ; third, power supplied simultaneously by the two types mentioned above. However, the known energy structure at present still has shortcomings in practice, notably:
[0006] 1. In a building, aside from lighting which consumes a greater amount of energy, air conditioning equipments which also consume a great deal of energy often are not included in energy saving items. Due to the building is always thermally affected by external and internal environments, an uncomfortable heated feeling frequently occurs inside the building. This problem has to be overcome through air conditioning. But the air conditioning, aside from providing a comfortable indoor environment, also generates thermal pollution such as consuming energy and producing waste heat. This not only creates ill consequences such as urban heat island effect and greenhouse effect, also seriously contaminates the eco-environment of the earth. It also results in huge waste of energy resources. Moreover, the climate temperature gradually rises due to the waste energy has been constantly discharged into the external environment. As a result, loading of air conditioning equipments increases and operation efficiency is lower.
[0007] 2. The known energy schemes of a building mostly focus on conversion of the generated electric power without fully considering better utilization of heat energy in the building and integration of the building and electric power. This is a big loophole in energy resource management. As a result a great deal of investment has been made on generation of electric power and utilization thereof, but heat energy of the building is wasted. And the heat inside and outside the building is not being treated as an energy resource and is poorly used. In many cases the heat inside and outside the building even is treated as waste heat and discharged. Thus energy saving effect cannot be easily achieved in terms of energy resource management.
[0008] 3. The renewable energy resources such as solar energy and wind power are constrained by natural conditions, and are not reliable in terms of electricity generation and timing. According the present energy resource management schemes, they can only be used as power supply at the generating instant. In the event that sunlight or wind power is sufficient, surplus electric power may be sold to the public power supply system 12 . But in peak load periods or during the energy apparatus 11 cannot meet power demand, users have to buy electric power from the public power supply system 12 . This results in a power price difference of selling the power at a lower price but buying the power at a higher price. In addition to energy loss incurred to the conversion system, the users do not enjoy their share of benefits. If a scheme can be developed to allow the users to use the surplus electric power onsite, or further convert and store, and balance energy demand and supply with other buildings in the neighborhood to establish a regional energy exchange mechanism, and get supply from the public power supply system 12 for the shortage, a significant portion of power expenditure can be saved.
[0009] Based on previous discussion it is obvious that the conventional energy structure does not have an integrated planning for the energy resources in a building. It also neglects the importance of effectively utilizing the internal and external heat energy of the building and integration of regional electric power. Although the Applicant has submitted R.O.C. patent application No. 91125414 aiming to flexibly use electric power in the off-peak period and store energy through an air-conditioning equipment, and release heat energy during peak hours to balance electric power usage periods, and ultimately save electric power and balance the power in the peak and off-peak periods, it still does not fully utilize the heat energy inside and outside the building, or fully integrate regional electric power to achieve flexible power usage. There are still rooms for improvement.
SUMMARY OF THE INVENTION
[0010] Therefore it is an object of the present invention to provide a building energy storage and conversion apparatus which includes at least a control unit, an electric power conversion unit, an energy conversion unit and a thermoelectric conversion unit. The electric power conversion unit has a power supply which can be regulated through the invention. The energy conversion unit generates cold and heat energy which can be utilized in an optimum fashion according power requirement. The invention also has a heat storage equipment to store heat (storing cold/heat energy), and release the cold/heat energy at a required time through. In the event that surplus cold/heat energy occurs the thermoelectric conversion unit can supply electric power. Thus energy resources can be converted and used in the optimum fashion. As a result, energy supply self-sufficiency can be achieved first for a building. Then balance of energy demand and supply can be accomplished with other buildings in the neighborhood to meet mutual requirements and establish a regional exchange mechanism to meet overall demand and supply. Finally, in the event that the self-generating electric power is not adequate, needed power can be obtained from a public electric power supply system. Thus energy resources can be managed and utilized onsite in a centralized fashion to reduce transmission loss of remote energy transportation. And energy saving effect can be achieved, and energy resources inside and outside the building can be flexibly utilized.
[0011] In one aspect, the electric power conversion unit is controlled by the control unit to control sources of various types of electric power. The electric power sources include at least one power supply, for instance, electric power provided by the public power supply system, electric power provided by the energy apparatus such as electric power converted from solar energy, electric power generated by wind power, electric power generated by fuel cells and electric power converted from other renewable energy sources.
[0012] In another aspect the energy conversion unit includes a heat source equipment and a heat storage equipment. The heat source equipment includes at least a host, a heat generator, a cold generator and an intermediate heat exchanger. The heat storage equipment includes a cold storage device and a heat storage device.
[0013] In yet another aspect, the thermoelectric conversion unit generates electric power by adopting See-back temperature difference thermoelectric effect that generates the electric power by conversion of thermoelectric effect of cold/heat energy temperature difference.
[0014] In yet another aspect, the energy storage and conversion apparatus further include an electricity storage unit to store surplus electric power through batteries.
[0015] The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic view of a conventional energy conversion scheme.
[0017] FIG. 2 is a schematic view of the structure of the invention.
[0018] FIG. 3 is a schematic view of the structure of the energy conversion unit of the invention.
[0019] FIG. 4 is flowchart- 1 of the invention.
[0020] FIG. 5 is flowchart- 2 of the invention.
[0021] FIG. 6 is a schematic view of the invention in operating conditions.
[0022] FIG. 7 is a schematic view of the structure of a second embodiment of the invention.
[0023] FIG. 8 is flowchart- 1 of the second embodiment of the invention.
[0024] FIG. 9 is flowchart- 2 of the second embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Referring to FIGS. 2 and 6 , the energy storage and conversion apparatus 3 according to the invention includes at least a control unit 31 , an electric power conversion unit 32 , an energy conversion unit 33 and a thermoelectric conversion unit 34 .
[0026] The control unit 31 aims to control operations of various units mentioned above to regulate and control optimal processing of storage and conversion of energy resources.
[0027] The electric power conversion unit 32 is controlled by the control unit 31 to control various types of input sources of electric power and provide electric power required by a building B. The power source includes at least one power supply, such as electric power provided by a public power supply system 42 , or electric power provided by an energy apparatus 41 such as electric power converted from solar energy, electric power generated by wind power, electric power generated by fuel cells and electric power converted from other renewable energy sources.
[0028] The energy conversion unit 33 aims to generate cold energy and heat energy and store heat (including cold energy and heat energy), and includes at least a heat source equipment 331 and a heat storage equipment 332 . The heat storage equipment 332 includes at least a cold storage device 3321 and a heat storage device 3322 .
[0029] The thermoelectric conversion unit 34 aims to generate electric power by adopting the See-back temperature difference thermoelectric effect to generate electric power by conversion of thermoelectric effect of cold/heat energy temperature difference.
[0030] The energy storage and conversion apparatus 3 uses the cold/heat energy stored in the heat storage equipment 332 , and directly supplies the stored cold/heat energy to a required cold environment C and a required heat environment H (the cold energy environment, depending on industrial requirements, may be divided into a number of situations such as below 30° C. for industrial use, 0-30° C. or 0-10° C. for commercial use; while heat energy environment may be divided into some other situations such as 50° C. or more for industrial use, and 40° C.-50° C. for commercial and household uses). Moreover, when the stored cold/heat energy is more than the use requirement, the surplus energy can be converted through the thermoelectric conversion unit 34 by applying See-back temperature difference thermoelectric effect to generate electric power. Therefore all or a designated portion of electric power needed in the building B can be supplied to achieve maximum utilization of energy resources in the building.
[0031] Refer to FIGS. 4 and 5 for process flow 5 of the invention (also referring to FIGS. 2 and 6 ). When the energy apparatus 41 starts operation (for instance, in the event of generating electric power through solar energy, the energy apparatus 41 receives photo energy of sunshine and converts to electric power), electric power E 1 is generated and transmitted to the electric power conversion unit 32 , and the control unit 31 compares a set value EOS of total electric power requirement of the building B with the electric power E 1 generated by the energy apparatus 41 (namely the control unit 31 is equipped with processing and detection capability). The process flow includes the procedures as follow:
[0032] 1. When the value of electric power E 1 generated by the energy apparatus 41 is greater than or equal to the set value EOS of total electric power requirement of the building B, namely E 1 ≧EOS (step 501 ), the electric power E 1 generated by the energy apparatus 41 can meet total electric power requirement EOS of the building B (generally is in off peak periods and electric power requirement in the building is smaller, such as clustered residences in daytime while people have gone to offices or other places). The surplus electric power has to be utilized. Hence the control unit 31 activates the energy conversion unit 33 , and judges whether heat energy Q generated by the energy conversion unit 33 is greater than or equal to a total required heat energy set value QOS (step 502 ) of the building B, and the following processes are executed accordingly:
[0033] (1) in a condition of Q≧QOS, the heat energy is surplus, and the heat storage equipment 332 is activated to store heat (storing cold/heat energy) (step 503 ); when the stored heat amount N reaches a heat storage set value NS, the control unit 31 activates the thermoelectric conversion unit 34 (steps 504 and 505 ), and the cold energy released by the cold storage device 3321 and the heat energy released by the heat storage device 3322 of the heat storage equipment 332 are being used to generate electric power E 2 by the thermoelectric conversion unit 34 through See-back temperature difference thermoelectric effect. The generated electric power E 2 can be converted to DC or AC power to supply the building B. In the event that the sum of the electric power E 1 generated by the energy apparatus 41 and the electric power E 2 generated by the thermoelectric conversion unit 34 is greater than or equal to the set value EOS of total electric power requirement of the building B, namely E 1 +E 2 ≧EOS (step 506 ), the electric power is in a surplus state, and step 507 is executed to determine whether the surplus power to be sold to the public power supply system 42 (step 507 ). If there is a sales contract between the building owner and the public power supply system 42 , step 508 is executed to sell the surplus electric power to the public power supply system; if there is no sales contract, step 509 is executed, namely electric power conversion is stopped.
[0034] (2) If the condition Q≧QOS does not exist, namely Q<QOS (step 510 ), the total required heat energy set value QOS of the building B is greater than the heat energy Q generated by the energy conversion unit 33 , then step 511 is executed, and the heat source equipment 331 directly supplies heat to the heat environment H (or cold environment c) of the building B (including supply of heat energy or cold energy). In the event that the stored heat amount N of the heat storage equipment 332 has reached the heat storage set value NS, it starts to release heat (release cold/heat energy) (steps 512 and 413 ); on the other hand, if the stored heat amount N is less than the heat storage set value NS, the heat storage equipment 332 proceeds heat storing (storing cold/heat energy) (step 514 ). Thus heat storing and releasing processes can be performed at the same time. This is another feature of the invention.
[0035] 2. In the event that the condition E 1 ≧EOS does not exist, namely E 1 <EOS, the electric power E 1 generated by the energy apparatus 41 cannot fully meet the set value EOS of total electric power requirement of the building B, and in the event that another condition E 1 +E 2 <EOS also exists, the set value EOS of total electric power requirement of the building B is greater than the sum of the electric power E 1 generated by the energy apparatus 41 and electric power E 2 generated by the thermoelectric conversion unit 34 , then the public power supply system 42 has to be included to supply the required electric power (steps 515 and 516 ); meanwhile, supply and demand condition of heat energy has to be determined. In the event that Q<QOS (step 517 ), the total required heat energy set value QOS of the building B is greater than the heat energy Q generated by the energy conversion unit 33 (step 510 ), the heat source equipment 331 directly supplies heat (step 511 ) to the heat environment H (or cold environment C) of the building B, including supply of heat energy or cold energy, and judges whether the stored heat amount N of the heat storage equipment 332 has reached the heat storage set value NS (step 513 ); if the stored heat amount N has reached the heat storage set value NS, the heat storage equipment 332 releases heat (releasing cold/heat energy) (step 513 ); on the other hand, if the stored heat amount N is less than the heat storage set value NS, the heat storage equipment 332 proceeds heat storing process (step 514 ).
[0036] The heat source equipment 331 includes at least a host 3311 , a heat generator 3312 , a cold generator 3313 and an intermediate heat exchanger 3314 (referring to FIG. 3 ). The host 3311 aims to perform circulation of refrigerant. The heat generator 3312 is a heat exchanger to generate heat energy sent to the heat storage device 3322 via a first pump 335 to supply heat energy required by the heat environment H. The cold generator 3313 is another heat exchanger to generate cold energy sent to the cold storage device 3321 via a second pump 334 to supply cold energy required by the cold environment C. The intermediate heat exchanger 3314 aids operation of the heat source equipment to regulate cold and heat energy requirements. In the event that cold energy requirement QC is approximate to heat energy requirement QH (namely QC≈QH), the intermediate heat exchanger 3314 suspends operation. In the event that the cold energy requirement QC is greater than the heat energy requirement QH (namely QC>QH), the intermediate heat exchanger 3314 discharges heat; in the event that the heat energy requirement QH is greater than the cold energy requirement QC (namely QH>QC), the intermediate heat exchanger 3314 absorbs heat.
[0037] Refer to FIG. 7 for a second embodiment of the invention. The energy storage and conversion apparatus 3 further has an electricity storage unit 35 to store the surplus electric power generated by the thermoelectric conversion unit 34 . Namely the electric power in the off peak period is stored to supply and meet power demand in the peak period.
[0038] Please refer to FIGS. 8 and 9 (also FIG. 7 ) for the process flow 6 of the second embodiment. When the energy apparatus 41 starts operation (for instance, in the event of generating electric power through solar energy, the energy apparatus 41 receives photo energy of sunshine and converts to electric power), electric power E 1 is generated and transmitted to the electric power conversion unit 32 , and the control unit 31 compares the set value EOS of total electric power requirement of the building B with the electric power E 1 generated by the energy apparatus 41 . When the value of E 1 is greater than or equal to the set value EOS, namely E 1 ≧EOS (step 601 ), the electric power E 1 generated by the energy apparatus 41 can meet total electric power requirement of the building B (generally is in the off peak periods). The surplus electric power has to be utilized. Hence the control unit 31 activates the energy conversion unit 33 , and judges whether heat energy Q generated by the energy conversion unit 33 is greater than or equal to the total required heat energy set value QOS (step 602 ) of the building B, and the following processes are executed accordingly:
[0039] (1) in the condition of Q≧QOS, the heat energy is surplus, and the heat storage equipment 332 is activated to store heat (step 603 ); a judgment also is made on whether the stored heat energy N reaches the heat storage set value NS (step 604 ); if the outcome is positive, the control unit 31 activates the thermoelectric conversion unit 34 , and cold energy released by the cold storage device 3321 and heat energy released by the heat storage device 3322 of the heat storage equipment 332 are being used to generate electric power E 2 by the thermoelectric conversion unit 34 through See-back temperature difference thermoelectric effect. The electric power E 2 generated by the thermoelectric conversion unit 34 can be converted to DC or AC power (step 605 ) to be utilized. In the event that the sum of the electric power E 1 generated by the energy apparatus 41 and the electric power E 2 generated by the thermoelectric conversion unit 34 is greater than or equal to the total electric power requirement EOS of the building B, the electric power is surplus, and the control unit 31 activates the electricity storage unit 35 to store electric power (steps 606 and 607 ), and judges whether an electric storage set value E 3 S has been reached (step 608 ); if the outcome is positive, another judgment is made on whether a contract for selling electric power between the building owner and the public power supply system 42 exists (steps 609 ); if the outcome also is positive, step 610 is executed to sell the surplus electric power to the public power supply system; if there is no sales contract, step 611 is executed, namely electric power conversion is stopped.
[0040] (2) If the condition Q≧QOS does not exist, namely Q<QOS (step 612 ), the total required heat energy set value QOS of the building B is greater than the total heat energy Q generated by the energy conversion unit 33 , then step 613 is executed, and the heat source equipment 331 directly supplies heat to the heat environment H (or cold environment C) of the building B (including supply of heat energy or cold energy). In the event that the stored heat amount N of the heat storage equipment 332 has reached the heat storage set value NS, it starts to release heat (steps 614 and 615 ); on the other hand, if the stored heat amount N is less than the heat storage set value NS, the heat storage equipment 332 proceeds heat storing process (step 616 ).
[0041] 4. In the event that the condition E 1 ≧EOS does not exist, namely E 1 <EOS, a number of situations may happen as follow:
(1) Judge whether E 1 +E 2 <EOS (step 617 ); if the outcome is positive, the sum of the electric power E 1 generated by the energy apparatus 41 and electric power E 2 generated by the thermoelectric conversion unit 34 is less than the set value EOS of total electric power requirement of the building B, then the control unit 31 activates the electricity storage unit 35 to release its stored electric power E 3 (step 618 ); (2) If E 1 +E 2 +E 3 <EOS, the electric power E 1 generated by the energy apparatus 41 , electric power E 2 generated by the thermoelectric conversion unit 34 and electric power E 3 of the electricity storage unit 35 cannot fully meet the set value EOS of total electric power requirement of the building B, additional power supply has to be obtained from the public power supply system 42 (steps 619 and 620 ), and a judgment of another condition Q<QOS also is made (step 621 ); if the outcome is positive, the total required heat energy set value QOS of the building B is greater than or equal to the heat energy Q generated by the energy conversion unit 33 , namely Q<QOS (step 612 ), step 613 is executed, and the heat source equipment 331 directly supplies heat to the heat environment H (or cold environment C) of the building B, including supply of heat energy or cold energy, and judges whether the stored heat amount N of the heat storage equipment 332 has reached the heat storage set value NS (step 614 ); if the outcome is positive, the heat storage equipment 332 releases heat (step 614 ); otherwise, if the stored heat amount N is less than the heat storage set value NS, the heat storage equipment 332 proceeds heat storing process (step 616 ).
[0044] As a conclusion, the building energy storage and conversion apparatus of the invention can regulate power supply of the electric power conversion unit, and use the cold/heat energy generated by the energy conversion unit, and store heat (cold/heat energy) through the heat storage equipment. In the event of requiring cold/heat energy, cold/heat energy can be released as desired. When heat energy is in a surplus state, electric power generation can be performed through the thermoelectric conversion unit. In the event that the electric power is surplus, the extra electric power can be stored in the electricity storage unit to supply the peak period. Hence the invention can manage diversified energy resources onsite in a centralized fashion to accomplish onsite self-sufficiency and integrate effectively. Thus energy resources inside and outside the building can be converted and utilized in an optimal fashion to save energy and flexibly deployed.
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A building energy storage and conversion apparatus includes at least a control unit, an electric power conversion unit, an energy conversion unit and a thermoelectric conversion unit to regulate energy sources of the electric power conversion unit. The energy conversion unit generates cold/heat energy which is stored through a heat storage equipment (for cold/heat energy). The cold/heat energy can be released when needed. When the cold/heat energy is in a surplus state, it can be converted to electric power through the thermoelectric conversion unit or stored in the form of electric power. Thus energy resources can be converted and utilized in an optimal fashion to achieve energy self-sufficiency of a building. Moreover, energy exchange with other buildings in the neighborhood can be done to balance demand and supply. In the event of energy shortage, the needed electric power is obtained from a public power supply system to establish a regional energy exchange mechanism to save energy and achieve flexible use of energy resources inside and outside the building.
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FIELD OF THE INVENTION
[0001] The present invention relates to apparatus for generating microspheres or microbubbles to enhance the blending of a fluid with a mainstream liquid.
BACKGROUND OF THE INVENTION
[0002] The increasing amount of chemicals introduced into water systems in homes and small businesses has been identified as one of the largest sources of environmental pollution and this practice continues to grow unabated. When chemicals are introduced into a closed residential water system, they are most frequently discharged directly into an overtaxed municipal waste treatment plant after a single use. Similarly, when chemicals are added in an open residential water system, for example an insecticide which is added to water by mixing through a gardening hose, most of the chemicals will eventually flow into the water table or catch basin to be recycled into the municipal water system.
[0003] There are many prior-art devices used for mixing or otherwise dispensing liquid chemicals in a residential or business water system. Most of these devices are used to dispense liquid soap, shampoo, insecticide, fertilizer or other additives in a stream of water by means of the force of the water under pressure through a faucet, shower head, garden hose, or the like. Some devices allow a user to choose between a variety of additives to be dispensed into the stream of water. Others allow the user to select a dilution ratio of an additive to be dispensed into the water stream. Still other devices are adaptable for use in a wide variety of residential and commercial applications including bath, kitchen, and garden.
[0004] All applications of the prior-art devices are primarily concerned with achieving a higher level of convenience and ease of use in dispensing additives in water. The prior art does not, however, seek to enhance the efficacy of an additive in order to allow reduction of the ratio of additive otherwise required to accomplish a given task, thus reducing the gross amount discharged into the municipal waste disposal system or the ground.
[0005] The present invention distinguishes itself from the aforementioned prior art in that it is capable of increasing the efficacy of the additive dispensed in the water, thus allowing a reduction in the gross amount of additive used to accomplish a given task. This increase of efficacy of an additive is made possible by apparatus in the mixing device that generates microspheres or microbubbles of the additive in the water stream for greater surface contact of the additive in the water, particularly in situations where the two fluids being mixed are incompatible otherwise mutually repellent, such as oil and water. It has been demonstrated that microbubble or microsphere technology accomplishes the mixing of such incompatible fluids, without the use of emulsifiers or other binding agents.
[0006] The present invention accomplishes this increase of efficacy by exploiting incipient cavitation nuclei inherent in liquids and their unique properties upon implosion, including microbubble shockwave and ultrasound generation. Microspheres, which are created when two liquids are combined or microbubbles, which are created when a liquid and a gas are combined, are both defined as bubbles having a mean diameter of under 100μ (0.1 mm). Consequently, the term microbubbles sometimes used hereinafter refers to both. The prior art has demonstrated that fluids in a micron state will provide dramatically accelerated mutual physical and chemical interaction with a gas or other liquid and often attain a 30% or higher reduction in ratio of additive required to attain a given result.
[0007] As shown in the prior art, microbubble generation arises from the inherent presence of incipient cavitation nuclei in liquids. Cavitation is the process whereby microbubbles form, grow, and collapse due to pressure differentials created in a liquid. Tremendous local energy is released when a microbubble collapses which causes a disproportionately increased rate of physical and chemical interaction between molecules of any additive and its surrounding liquid. This then greatly enhances the efficacy of the additive in the mixture.
[0008] There are four basic methods of inducing cavitation: hydrodynamic, acoustic, optic and particle. The present invention makes use of a hydrodynamic method produced by pressure variations in a flowing liquid due to the geometry of the system. Cavitation occurs when the net pressure of the flowing liquid becomes approximately equal to the vapor pressure of the liquid.
[0009] Despite the fact that cavitation generation of microbubbles and the generation of the associated phenomena of ultrasound and shockwave has long been held to be particularly detrimental in hydrodynamic systems, the commercial, medical, and scientific communities have nonetheless begun to successfully exploit beneficial aspects of this technology to dramatically improve physical and chemical reactions as well as permit previously unattainable reactions and emulsions. A wide variety of methods have been developed by those communities to generate microbubbles including electrically generated ultrasonic vibrations, ceramic contact plates, cross-membranes, certain venturi configurations with external pumps, small scale oxygen injection apparatuses, and microbiological reactions, among others.
[0010] Commercial communities have utilized microbubble technology to sharply improve chemical and physical reactions such as mixing, heat exchange, flocculation, oxidation and reduction in fields as diverse as synthetic gas production, cancer imaging, wastewater treatment and mineral processing. Scientific and medical communities have utilized microbubble technology to open new lines of research in cold fusion, non-invasive surgical procedures, and transdermal therapy, among others. However, the means used by those communities for producing microbubbles and utilizing the beneficial properties resulting therefrom cannot be easily adapted to home use for a variety of reasons. For example, a pump or electrical device is usually involved which gives rise to concerns about safety, size, and cost that would preclude home use. Being generally highly sophisticated in nature, these systems for production of microbubbles present difficulties not easily overcome in the areas of mass-market manufacturing, installation and operation and thus are not currently available for home or other uses requiring low cost production for mixing a fluid gas or liquid with a mainstream liquid.
[0011] What has not been generally appreciated by the prior art is that hydrodynamic cavitation per se is not necessarily a negative externality that should always be avoided altogether in hydrodynamic systems. What the present invention seeks to exploit is that in hydrodynamic cavitation in the mainstream of a liquid, the liquid system itself can be utilized to generate microbubbles and its associated phenomena to achieve a variety of benefits, one of which is the reduction of the ratio of an additive fluid to the mainstream liquid in order to reduce the additive needed in the mainstream liquid.
[0012] The present invention can achieve mixing at the micron level without altering the infrastructure of a residence or small business through the use of microbubbles. Because the present invention can be powered solely by the pressure of a mainstream liquid flowing from a source and utilizes no electricity, pump, or other mechanical devices, the power of a municipal water system is sufficient for the present invention to attain mixing of fluids in a mainstream flow of water at a micron level, such as detergents or chlorine, despite pressures as low as 25 PSI and low flow rates of 2.25 to 5.0 gallons per minute. Certain types of industrial static mixers, e.g., U.S. Pat. No. 4,270,576 (Takeda), operate with electricity, pump, or other external means and therefore cannot be self-contained for insertion in a residential or small business water system, such as in a clothing or dish washing system.
SUMMARY OF THE INVENTION
[0013] In accordance with the present invention, apparatus for mixing a fluid (gas or liquid) with a liquid of a primary stream comprises a section of pipe or tube attachable to a source of main-stream liquid under pressure. The defined space in the section of tube is provided with a constriction device between its inlet and outlet for the purpose of increasing the velocity of the main-stream flow of liquid through the constriction device and thus lowering the pressure of the main-stream liquid at the constriction in accordance with Bernoulli's principle. An aspiration tube having an outer diameter substantially smaller than the inner diameter of the tube section and having its inlet coupled to a source or reservoir of the fluid to be mixed with the main stream of liquid has its outlet centrally disposed upstream in the tube section and proximate to the constriction device such that low pressure of the main stream of liquid flowing around the aspiration tube and through the restricted space between the aspiration tube outlet and the constriction device produces a venturi effect so that the fluid is drawn from the aspiration tube into the mainstream of liquid.
[0014] The fluid drawn in from the aspiration tube will initially form a column of fluid surrounded by liquid as the liquid begins to decelerate. In order to promote cavitation, i.e., the formation of microbubbles in the liquid for optimal mixing or blending of the fluid with the liquid, staggered pins are provided that extend out from the wall of the pipe towards its axis in a section downstream from the constriction device. The length of these pins is chosen to be approximately equal to the theoretical distance from the wall to the interface of the column of fluid and the surrounding fluid. Since that interface is not precisely defined due to the fact that some blending will begin to occur immediately after the exit of the fluid from the aspiration tube, the theoretical interface may be taken at least at the center of that region of initial blending and preferably the inner circumference of that region. The purpose of the protruding pin is to create microscopic turbulence in the region of blending for optimal inducement of cavitation, which is to promote the formation and activity of microbubbles in the liquid for maximum blending of the fluid with the mainstream liquid.
[0015] The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention will best be understood from the following description when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] [0016]FIG. 1 is a perspective view of a first embodiment of the present invention using a straight-through flow pipe or tube section 2 and an aspiration tube 4 in front of a flow constriction device 3 in the form of a truncated conical surface followed by a turbulence section 5 with protuberances 7 and a pressure reduction section 6 .
[0017] [0017]FIG. 2 is a perspective view of a second embodiment of the invention using a constriction device consisting of two opposing flow deflectors 11 , 12 in the form of semidiscs at opposing angles with respect to mainstream liquid flow through the tube section.
[0018] [0018]FIG. 3 is a perspective view of another embodiment of the invention having an alternate geometry, namely an L-shaped cylinder or tube section, in order that the aspiration tube need not be bent.
[0019] [0019]FIG. 4 is a perspective view of the invention shown in FIG. 1 incorporated in a sink faucet 9 .
[0020] [0020]FIG. 5 is a perspective view of the present invention shown in FIG. 1 with the aspiration tube commencing at a remote distance from the flow constriction device and extending centrally and coaxially through an extender tube section 10 or hose to a position proximate the flow constriction device.
DETAILED DESCRIPTION OF INVENTION
[0021] The embodiments of the invention illustrated in the drawings are directed to the provision of apparatus for generating microspheres or microbubbles while mixing a fluid with a mainstream liquid at a micron level using the mainstream liquid pressure without the use of any other source energy, or other devices, based on the current theories of cavitation generating microspheres or microbubbles described as follows.
[0022] This invention exploits the presence of incipient cavitation nuclei present in liquids. That nuclei, when stretched, subsequently collapses and produces the phenomenon known as cavitation that results in microspheres or Microbubbles. Cavitation occurs when variational tensile stresses are superimposed on the prevailing ambient pressure of a flowing liquid such that the total net pressure becomes approximately equal to the vapor pressure of the liquid. While there exist alternative theories that might also explain this cavitation reaction, hydrodynamic cavitation seems to be the most appropriate explanation underlying the effects produced by the present invention.
[0023] Referring now to FIG. 1, which shows a detailed perspective view of a first embodiment of the present invention comprising a straight-through section of pipe or tube 2 which can be made from a variety of inexpensive materials and which is installed or attached by a coupler 1 to the end of or within a standard plumbing fixture or configuration (not shown) such as a water tap, faucet, showerhead, garden hose, washing machine water hose, dishwasher water hose, or the like, the mainstream liquid flowing through the tube 2 and comes into contact with a flow constriction device 3 in the form of a truncated conical surface oriented so that the liquid must pass through the base thereof (having a diameter equal to the diameter of the tube 2 ) and out of the open top thereof, the diameter of which open top is less than the diameter of the tube 2 , thereby creating a venturi effect as the liquid passes therethrough. That in turn creates a progressively decreasing pressure zone within the constriction device 3 which draws a fluid out of an aspiration tube 4 , having an outer diameter substantially smaller than the inner diameter of the tube 2 and having an outlet disposed centrally and coaxially with respect to the tube 2 proximate the constriction device 3 , somewhere between the base and open top thereof. The mainstream liquid entrained with fluid and ambient air drawn from the aspiration tube 4 mix as they enter a reaction chamber 5 . A central high pressure liquid jet created by the constriction device 3 is located at the core mix entering the reaction chamber 5 .
[0024] The fluid flow through the aspiration tube 4 is not intended to be present at all times. Instead, an on/off valve (not shown) is momentarily turned on such that ambient air (trapped in the aspiration tube until the valve is turned on) will be entrained with the fluid to be mixed. Entrained air does not have any adverse effect on the operation of the invention but rather is believed to aid in the generation of microbubbles. On the other hand, its presence is not deemed to be critical.
[0025] It is believed that the additive fluid enters the reaction chamber 5 in a column with the mainstream liquid swirling around the column of additive fluid, but whether or not the liquid is swirling, it is known to be surrounding the column of additive fluid. Fluids not already mixed around that central column of additive fluid tend to move outwardly towards the mainstream liquid as the column expands and come into contact with a plurality of protuberances 7 that protrude into the core of additive fluid. Collision of the liquid with the protuberances 7 creates a number of vortices and low and high pressure zones whereby transient and incipient cavities inherent to the fluids being mixed are stretched and pulled. Upon exit from the reaction chamber 5 , the fluids with stretched cavities enter a downstream zone 6 of the tube 2 , defined by the absence of any protuberances, where the stretched cavitation nuclei collapse or implode onto each other causing the phenomenon known as cavitation followed by the production of microspheres accompanied by shockwaves. The microspheres flowing out of the zone 6 explode, thereby completing a thorough mixture of liquid and additive fluid and in the process producing ultrasound waves.
[0026] Although FIG. 1 shows a typical embodiment of the present invention, it will be appreciated that variations in the overall design geometry of the apparatus, as well as variations in the flow constriction device configuration and the protuberances will occur to those skilled in the art.
[0027] [0027]FIG. 2 illustrates an alternate flow constriction device to be compared and contrasted to that of FIG. 1. In FIG. 2 the flow constriction device 3 is in the form of a three-dimensional surface of a truncated cone coaxially attached to the wall of the tube 2 , as shown, with its central opening at the top sufficiently small as to cause a venturi effect of increasing the velocity of the main stream liquid flow therethrough as its pressure is reduced with the maximum reduction of pressure at the outlet opening, thus allowing the mainstream of liquid to effectively “draw” fluid at a higher pressure from the aspiration tube 4 as the mainstream liquid passes through the constriction device 3 . In contrast, the flow constriction device 3 ′ in FIG. 2 comprises two semidisc flow constriction panels 3 a, 3 b positioned at an acute angle to each other and attached to the wall of the tube 2 , thus leaving a restricted space between the panels to permit the mainstream of liquid and entrained fluids to pass therethrough with a swirling motion since flow restriction panels 3 a and 3 b impart circular deflection to the flow with attendant increase in velocity and decrease in pressure of the mainstream liquid and entrained fluids. It is to be understood, however, that such flow constriction devices shown in FIG. 1 and FIG. 2 are for illustrative purposes only, and that other flow constriction devices of different design or shapes can be used to accomplish the aforementioned creation of the venturi.
[0028] [0028]FIG. 3 illustrates an alternate overall design geometry of the apparatus wherein the tube 2 ′ is L-shaped. An advantage of the L-shaped tube 2 ′ is that the aspiration tube 4 ′ is then straight so there is no restriction to the flow of additive fluid and entrained air. Although the L-shaped tube 2 ′ results in a slight decrease in the overall flow rate of the system, it would not noticeably alter the effectiveness of the apparatus.
[0029] In both embodiments, the space between the tips of the opposing protuberances is preferably equal to the inner diameter of the aspiration tube 4 . In the embodiment of FIG. 1, the outlet of the aspiration tube is spaced upstream from the constriction device 3 and has an inner diameter less than the diameter of the downstream opening of that constriction device, both of which serve to allow the fluid being aspirated and the mainstream liquid to flow with the fluid flowing in a column surrounded by the mainstream liquid. The protuberances 7 are selected to be of a length sufficient to at least extend through the outer layer of the mainstream liquid to the inner column of fluid and preferably slightly into the column of fluid. Consequently, an acceptable criterion is a protuberance length approximately equal to the distance from the inner surface of the tube 2 to the inner surface of the aspiration tube 4 at the outlet thereof.
[0030] The same criterion applies in the embodiment of FIG. 2 where the constriction device is comprised of two semidiscs 3 a and 3 b which together impart a swirl in the downstream flow of the mainstream liquid and at the same time produces a low pressure area inside the swirl as the velocity of the liquid increases. The low pressure inside the swirl then draws a column of additive fluid into the tube 2 downstream of the constriction device semidiscs. In this case, the swirling mainstream liquid surrounding the additive fluid will tend to confine the additive fluid to a column having a diameter equal to the inside diameter of the aspiration tube outlet. However, the greater velocity of the swirling liquid produces a shearing stress at the interface between the column of additive fluid and the swirling mainstream liquid. This adds to the tensile stress in the transient cavities, thus promoting greater hydrodynamic cavitation. Nevertheless, the protuberances should meet the same criterion as in the first embodiment shown in FIG. 1, i.e., should extend at least through the swirling mainstream liquid and preferably into the column of additive fluid.
[0031] In general, for purposes of the present invention, the design of the solid protuberances may take a variety of shapes. For instance, an inverted polygonal column or tetragonal pyramid may be used to provide or induce the formation of a series of high and low pressure zones in the reaction chamber 5 through which the flow stream passes to produce turbulence without any deviation from the spirit and scope of the present invention, thereby promoting the cavitation of fluids passing through reaction chamber 5 . Similarly, the placement of staggered protuberances along the inner wall of reaction chamber 5 may be either zigzagged along lines parallel to the tube axis along circular lines around that axis or both. The objective is to use an arrangement of protuberances which provide maximum turbulence by collision with protuberances. Thus, a multitude of low and high pressure zones affecting the fluids (additive fluid and air) and mainstream liquid being mixed are created as they pass through the reaction chamber 5 . That enhances cavitation that is followed by the creation of microspheres which in turn maximizes the mixing of additive fluid (liquid or gaseous and entrained air) with the mainstream liquid.
[0032] As shown in FIG. 1, FIG. 3, and FIG. 5, the position and design of aspiration tube 4 may easily be modified to adapt it to various overall system design considerations relating to application constraints that require an extender 10 for the tube 2 , provided that the inlet of the aspiration tube 4 commences at a point upstream from the constriction device 3 and the outlet of the aspiration tube 4 is aligned with the center line of the constriction device 3 and between a plane at the front of the constriction device (defined by its circumference connected to the tube wall) and the opening at the outlet thereof to allow some significant space for flow of mainstream liquid from the inlet of the tube 2 but preferably at the front plane of the constriction device. It will also be appreciated by those skilled in the art that the aspiration tube 4 can be used in conjunction with any number of available additive fluid dispensing systems, including multiple fluid dispensing systems, as the aspiration created by the venturi-effect of the constriction device is strong enough to draw but the most viscous fluids into the apparatus. Additionally, it will be appreciated by those skilled in the art that other configurations for additive fluid introduction systems may readily occur to those skilled in the art without significantly altering the spirit or results of the present invention.
[0033] Although a description of the present invention has been illustrated in various configurations, and one application has been illustrated in connection with a sink faucet, it should be appreciated that the invention may be adapted to many medical and scientific applications as well as other residential applications, and although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications may readily occur to those skilled in the art. Consequently, it is intended that the claims be interpreted to cover such modifications and equivalents thereof.
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A unitary, self-contained apparatus for generating microbubbles using a pipe section with a constriction device for producing a venturi effect to cause a mainstream liquid flowing under pressure in the pipe section to draw a column of additive fluid into the mainstream liquid from an aspiration tube for mixing with the liquid and a turbulence part of the pipe section immediately downstream from the constriction device. Protrusions from the inside surface of the turbulence part of the pipe section protrude to at least the theoretical interface between the column of additive fluid and the surrounding mainstream liquid and preferably beyond, where the theoretical interface is a circumference of the column of additive fluid having a radius equal to the radius of the inside surface of the aspiration tube.
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FIELD OF THE INVENTION
[0001] The present invention relates generally to protecting a child from spills and, more particularly, to protecting a child from spills by use of a protective garment.
BACKGROUND
[0002] Clothes for children are difficult to keep clean and tidy. When children are infants, they frequently soil their clothes by spitting up, drooling, and dripping milk onto their clothes. Older children typically soil their clothes by spilling food and drinks on them and by participating in arts and crafts activities.
[0003] Frequently changing soiled clothes for both infants and older children are often times very inconvenient. For example, many times changing an infant's clothes disrupts the natural sleep cycle of the infant. Additionally, by changing an infant's clothes, the infant can wake up causing unnecessary disruption for both the infant and the caregiver.
[0004] In another example, changing an older child's clothes is inconvenient because at least one extra set of clothes is packed and transported by the care-giver while traveling. Further, attempting to change an older child's clothes is sometimes difficult when the child is actively participating in an activity.
[0005] By preventing the clothes from becoming soiled in the beginning, stress to the caregiver and infant is avoided, and time and energy is saved by not needing to change a child's outfit and wash the child's clothes as often. Further, costs for replacing permanently stained and soiled clothes is also saved.
SUMMARY
[0006] In one embodiment, the methods and apparatuses include a shell surface comprising: a front portion having a continuous surface for protecting a user from contamination, wherein the continuous surface provides a barrier between the contamination and the user, wherein the front portion protects a chest and abdomen area of the user from the contamination; an arm portion connected to the front portion, wherein the arm portion protects the arm from contamination; and a leg portion connected to the front portion, wherein the leg portion is configured to protect a leg of the user; a first fastener coupled to the leg portion for fastening the leg portion around the leg of the user; and a second fastener coupled to the front portion for fastening the front portion to the user wherein the second fastener is configured to attach the front portion to a side portion of the user, wherein the shell surface is configured to attach to the user through the first fastener and the second fastener while a portion of a back of the user is blocked.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate and explain one embodiment of the methods and apparatuses for protecting a child from spills. In the drawings,
[0008] FIG. 1 is a front view consistent with one embodiment of the methods and apparatuses for protecting a child from spills;
[0009] FIG. 2 is a back view consistent with one embodiment of the methods and apparatuses for protecting a child from spills;
[0010] FIG. 3 is a perspective view consistent with another embodiment of the methods and apparatuses for protecting a child from spills;
[0011] FIG. 4 is a perspective view consistent with yet another embodiment of the methods and apparatuses for protecting a child from spills;
[0012] FIGS. 5A, 5B , 5 C, and 5 D illustrate a fastener consistent with one embodiment of the methods and apparatuses for protecting a child from spills;
[0013] FIG. 6 is a flow diagram consistent with one embodiment of the methods and apparatuses for protecting a child from spills;
[0014] FIGS. 7A, 7B , and 7 C are perspective views of the protective garment consistent with the flow diagram of FIG. 6 ;
[0015] FIGS. 8A, 8B , and 8 C are perspective views of the protective garment consistent with the flow diagram of FIG. 6 ;
[0016] FIG. 9 illustrates a patch consistent with one embodiment of the methods and apparatuses for protecting a child from spills; and
[0017] FIGS. 10A, 10B , and 10 C illustrate additional embodiments of the methods and apparatuses for protecting a child from spills.
DETAILED DESCRIPTION
[0018] The following detailed description of the methods and apparatuses for protecting a child from spills refers to the accompanying drawings. The detailed description is not intended to limit the methods and apparatuses for protecting a child from spills. Instead, the scope of the methods and apparatuses protecting a child from spills are defined by the appended claims and equivalents. Those skilled in the art will recognize that many other implementations are possible, consistent with the present invention.
[0019] References to a “child” include a newborn child, an infant child, and an older child.
[0020] References to “clothes” include any undergarments, shirts, pants, dresses, jumpers, and outer wear worn by a child.
[0021] References to “caregiver” include any persons taking care of a child.
[0022] In one embodiment, the methods and apparatuses for protecting a child from spills allows the caregiver to protect the child from soiling the child's clothes. For example, the invention prevents food and drinks from staining and soiling the child's clothes at feeding time, and prevents paints and dirt from soiling the child's clothes at play time.
[0023] In another embodiment, the methods and apparatuses for protecting a child from spills allows the child wearing the apparatus to move freely while still protecting the child's clothes from spills.
[0024] Further, the methods and apparatuses provide air circulation for the child while still protecting the child's clothes. In one embodiment, a portion of the back side of the child is left open, thus allowing air circulation to prevent the child from becoming too warm.
[0025] In yet another embodiment, the caregiver is able to place apparatus for protecting a child from spills onto the child without disturbing the child. For example, access to the back portion of the child is not needed to securely place the apparatus onto the child. The child can be sitting or laying down while the securing the apparatus onto the child.
[0026] FIG. 1 is a diagram illustrating a front view of a garment 100 that is one embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 100 is configured to protect a child's clothes from being soiled. The garment 100 is also designed to enable a caregiver to easily affix the garment 100 to the child and to remove the garment 100 from the child. In one embodiment, the garment 100 includes a front surface 110 , a pair of sleeves 120 , a pair of elastic bands 125 , a neck opening 130 , and a pair of legs 140 .
[0027] In one embodiment, the front surface 110 , the pair of sleeves 120 , and the pair of legs 140 are made of a water resistant material. In one embodiment, the water resistant material includes a water resistant fabric, a plastic coated fabric, a wax coated fabric, goretex, non-woven materials such as DuPont®, Tyvek®, or Sontara®, material used for disposable diapers, and material used in disposable, temporary protection garments in the food industry or in medical garments.
[0028] In one embodiment, the front surface 110 is configured to protect the front torso area of the child from spills or soiling. For example, when the garment 100 is worn by the child, the front surface 110 protects the child's torso area from being splattered by food, drinks, mud, or other substances.
[0029] In one embodiment, the neck opening 130 is configured to accommodate a child's neck. Further, the pair of sleeves 120 are connected to the front surface 110 and configured to accept the arms of a child. The pair of elastic bands 125 are positioned on the pair of sleeves 120 to securely fit the pair of sleeves 120 against the user's arms and to prevent contaminants from reaching the user's arms through the pair of sleeves 120 . The pair of legs 140 are connected to the front surface 110 and configured to accept the legs of a child.
[0030] FIG. 2 is a diagram illustrating a back view of the garment 100 that is one embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 100 is configured to protect a child's clothes from being soiled. The garment 100 is also designed to enable a caregiver to easily affix the garment 100 to the child and to remove the garment 100 from the child. In one embodiment, the garment 100 includes the front surface 110 , a back surface 210 , a pair of sleeves 120 , a neck opening 130 , a pair of legs 140 , a back fastener 220 , leg fasteners 230 , and a body fastener 250 .
[0031] In one embodiment, the back surface 210 is connected to the back fastener 220 . The back surface 210 in conjunction with the back fastener 220 are configured to attach the upper portion of the garment 100 to the child. In one embodiment, the back fastener 220 is configured such that the upper portion of the garment 100 can be attached the child while the child's back is obstructed. In one example, the child's back is obstructed when the child is laying on his/her back or when the child is seated in a high chair, a car seat, a chair with a back rest, and the like.
[0032] A back opening 260 is shown within the back surface 210 . The back opening 260 provides the child with sufficient air circulation. Further, the back opening 260 allows the upper portion of the garment 100 to be attached to the child without needing access to the back side of the child.
[0033] In one embodiment, the leg fasteners 230 are each connected to one of the pair of legs 140 . In one embodiment, the pair of legs 140 in conjunction with the leg fasteners 230 are configured to secure the pair of legs 140 around the child's legs without having complete access to the back portion of the child's legs. For example, if the child is seated or laying down, the pair of legs 140 of the garment 100 can be secured to the legs of the child without having complete access to the back portion of the child's legs.
[0034] In one embodiment, the inside portion of the front surface 110 is connected to the body fastener 250 . In one embodiment, the body fastener 250 is configured to help retain the front surface 110 of the garment 100 against the upper portion of the child. For example, the body fastener 250 attaches to the clothes of the child and helps keep the upper portion of the garment 100 attached to the upper body of the child in conjunction with the back fastener 220 .
[0035] FIG. 3 is a diagram illustrating a perspective view of the garment 300 that is another embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 300 is configured to protect a child's clothes from being soiled. The garment 300 is also designed to enable a caregiver to easily affix the garment 300 to the child and to remove the garment 300 from the child without having any access to the back portion of the child. In one embodiment, the garment 300 includes the front surface 310 , a pair of sleeves 320 , a neck opening 330 , a pair of legs 340 , a back fastener 350 , leg fasteners 360 , and a body fastener 370 .
[0036] In one embodiment, the front surface 310 , the pair of sleeves 320 , and the pair of legs 340 are made of a water resistant material. In one embodiment, the water resistant material includes a water resistant fabric, a plastic coated fabric, a wax coated fabric, goretex, non-woven materials such as DuPont®, Tyvek®, or Sontara®, material used for disposable diapers, and material used in disposable, temporary protection garments in the food industry or in medical garments.
[0037] In one embodiment, the front surface 310 is configured to protect the front torso area of the child from spills or soiling. For example, when the garment 300 is worn by the child, the front surface 310 protects the child's torso area from being splattered by food, drinks, mud, or other substances.
[0038] In one embodiment, the neck opening 330 is configured to accommodate a child's neck. Further, the pair of sleeves 320 are connected to the front surface 310 and configured to accept the arms of a child. The pair of legs 340 are connected to the front surface 310 and configured to accept the legs of a child.
[0039] In one embodiment, the front surface 310 is connected to the back fastener 350 . The front surface 310 in conjunction with the back fastener 350 are configured to attach the upper portion of the garment 300 to the child. In one embodiment, the back fastener 350 is configured such that the upper portion of the garment 300 can be attached the child while the child's back is completely obstructed. The back fastener 350 is configured to attach to the side of the child. In one embodiment, the back fastener 350 is configured to attach to the child's clothes. In one example, the child's back is completely inaccessible while the child is strapped into a car seat.
[0040] In one embodiment, the back of the child is open and not covered by the garment 300 . By not covering the back portion of the child, the child has sufficient air circulation. Further, the back fastener 350 allows the upper portion of the garment 300 to be attached to the child without needing access to the back portion of the child.
[0041] In one embodiment, the leg fasteners 360 are each connected to one of the pair of legs 340 . In one embodiment, the pair of legs 340 in conjunction with the leg fasteners 360 are configured to secure the pair of legs 340 around the child's legs without having any access to the back portion of the child's legs. For example, if the child is strapped into a car seat, the pair of legs 340 of the garment 300 can be secured to the legs of the child without having access to the back portion of the child's legs. For example, the leg fasteners 360 are configured to attach to the side portion of the child's legs.
[0042] In one embodiment, the inside portion of the front surface 310 is connected to the body fastener 370 . In one embodiment, the body fastener 370 is configured to help retain the front surface 310 of the garment 300 against the upper portion of the child. For example, the body fastener 370 attaches to the clothes of the child and helps keep the upper portion of the garment 300 attached to the upper body of the child in conjunction with the back fastener 350 .
[0043] FIG. 4 is a diagram illustrating a perspective view of the garment 400 that is another embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 400 is configured to protect a child's clothes from being soiled. The garment 400 is also designed to enable a caregiver to easily affix the garment 400 to the child and to remove the garment 400 from the child without having any access to the back portion of the child. In one embodiment, the garment 400 includes the front surface 410 , a pair of sleeves 420 , a neck opening 430 , a pair of legs 440 , a back fastener 450 , leg fasteners 460 , a body fastener 470 , a neck fastener 480 , and arm fasteners 485 .
[0044] In one embodiment, the front surface 410 , the pair of sleeves 420 , and the pair of legs 440 are made of a water resistant material. In one embodiment, the water resistant material includes a water resistant fabric, a plastic coated fabric, a wax coated fabric, goretex, non-woven materials such as DuPont®, Tyvek®, or Sontara®, material used for disposable diapers, and material used in disposable, temporary protection garments in the food industry or in medical garments.
[0045] In one embodiment, the front surface 410 is configured to protect the front torso area of the child from spills or soiling. For example, when the garment 400 is worn by the child, the front surface 410 protects the child's torso area from being splattered by food, drinks, mud, or other substances.
[0046] In one embodiment, the neck opening 430 is configured to accommodate a child's neck. In addition, the neck fastener 480 securely attaches the neck opening 430 to the child's neck without requiring access to the back portion of the child. In one embodiment, the neck fastener 480 attaches to the front portion of a child's clothing.
[0047] Further, the pair of sleeves 420 are connected to the front surface 410 and configured to accept the arms of a child. The pair of legs 440 are connected to the front surface 410 and configured to accept the legs of a child.
[0048] In one embodiment, the front surface 410 is connected to the back fastener 450 . The front surface 410 in conjunction with the back fastener 450 are configured to attach the upper portion of the garment 400 to the child. In one embodiment, the back fastener 450 is configured such that the upper portion of the garment 400 can be attached the child while the child's back is completely obstructed. The back fastener 450 is configured to attach to the side of the child. In one embodiment, the back fastener 450 is configured to attach to the child's clothes. In one example, the child's back is completely inaccessible while the child is strapped into a car seat.
[0049] In one embodiment, the back of the child is open and not covered by the garment 400 . By not covering the back portion of the child, the child has sufficient air circulation. Further, the back fastener 450 allows the upper portion of the garment 400 to be attached to the child without needing access to the back portion of the child.
[0050] In one embodiment, the leg fasteners 460 are each connected to one of the pair of legs 440 . In one embodiment, the pair of legs 440 in conjunction with the leg fasteners 460 are configured to secure the pair of legs 440 around the child's legs without having any access to the back portion of the child's legs. For example, if the child is strapped into a car seat, the pair of legs 440 of the garment 400 can be secured to the legs of the child without having access to the back portion of the child's legs. For example, the leg fasteners 460 are configured to attach to the side portion of the child's legs.
[0051] In one embodiment, the inside portion of the front surface 410 is connected to the body fastener 470 . In one embodiment, the body fastener 470 is configured to help retain the front surface 410 of the garment 400 against the upper portion of the child. For example, the body fastener 470 attaches to the clothes of the child and helps keep the upper portion of the garment 400 attached to the upper body of the child in conjunction with the back fastener 450 .
[0052] In one embodiment, the arm fasteners 485 are each connected to one of the pair of sleeves 420 . In one embodiment, the pair of sleeves 420 in conjunction with the arm fasteners 485 are configured to secure the pair of sleeves 420 around the child's arms without having complete access to the back portion of the child's arms. For example, if the child is seated or laying down, the pair of sleeves 420 of the garment 400 can be secured to the arms of the child without having complete access to the back portion of the child's arms.
[0053] The elements shown in FIGS. 1-4 are shown for illustrative purposes showing multiple embodiments of the invention. Elements can be added, deleted, or combined without departing from the invention.
[0054] FIGS. 5A, 5B , 5 C, and 5 D illustrate fastener devices for use with the methods and apparatuses for protecting a child from spills. In one embodiment, the fasteners as shown in FIGS. 5A, 5B , 5 C, and 5 D are utilized within the garments 100 , 300 , and 400 .
[0055] FIG. 5A illustrates a hook and loop fastener 500 . A first surface 510 is coupled to a first garment surface 505 . The first surface 510 includes a hook surface 515 that is configured to removably attach to the second surface 520 . The second surface is coupled to a second garment surface 507 . For example, the first surface 510 selectively mates with the second surface 520 through the hook surface 515 . Since the first surface 510 is coupled to the first garment surface 505 and the second surface 520 is coupled to the second garment surface 507 , the first garment surface 505 selectively attaches to the second garment surface 507 via the hook and loop fastener 500 .
[0056] In one embodiment, the first garment surface 505 represents a portion of a garment such as the garments 100 , 300 and 400 . Further, the second garment surface 507 represents another portion of the same garment. In another embodiment, the second garment surface 507 represents a child's clothing worn by the child such that the garment is selectively attached to the child's clothing through the hook and loop fastener 500 .
[0057] FIG. 5B illustrates a hook and loop fastener 520 . A first surface 510 is coupled to a first garment surface 505 . The first surface 510 includes a hook surface 515 that is configured to removably attach to a second garment surface 507 . For example, the first surface 510 selectively mates with the second garment surface 507 through the hook surface 515 . Since the first surface 510 is coupled to the first garment surface 505 , the first garment surface 505 selectively attaches to the second garment surface 507 via the hook and loop fastener 520 .
[0058] In one embodiment, the first garment surface 505 represents a portion of a garment such as the garments 100 , 300 and 400 . Further, the second garment surface 507 represents another portion of the same garment. In another embodiment, the second garment surface 507 represents a child's clothing worn by the child such that the garment is selectively attached to the child's clothing through the hook and loop fastener 520 .
[0059] FIG. 5C illustrates a button fastener 525 . A tab 530 is coupled to a first garment surface 505 . A receptacle 535 is coupled to the second garment surface 507 . The tab 530 is configured to be inserted and selectively retained by the receptacle 535 . For example, the first surface 510 selectively mates with the second garment surface 507 through the tab 530 and receptacle 535 . In one embodiment, the first garment surface 505 represents a portion of a garment such as the garments 100 , 300 and 400 . Further, the second garment surface 507 represents another portion of the same garment.
[0060] The hook and loop fastener are utilized in FIGS. 5A and 5B as one embodiment of a fastener. Other fasteners that attach to itself and other objects such as a child's clothes can be utilized without departing from the scope of the invention.
[0061] FIG. 5D illustrates an adhesive fastener 540 . An adhesive layer 545 is coupled to a first garment surface 505 . The adhesive layer 545 is configured to selectively mate with the second garment surface 507 . For example, the first surface 510 selectively mates with the second garment surface 507 through the adhesive layer 545 .
[0062] In one embodiment, the first garment surface 505 represents a portion of a garment such as the garments 100 , 300 and 400 . Further, the second garment surface 507 represents another portion of the same garment. In another embodiment, the second garment surface 507 represents a child's clothing worn by the child such that the garment is selectively attached to the child's clothing through the adhesive fastener 540 .
[0063] The flow diagram as depicted in FIG. 6 is one embodiment of the methods and apparatuses for protecting a child from spills. The blocks within the flow diagram can be performed in a different sequence without departing from the spirit of the methods and apparatuses for protecting a child from spills. Further, blocks can be deleted, added, or combined without departing from the spirit of the methods and apparatuses for protecting a child from spills.
[0064] The flow diagram in FIG. 6 illustrates placing a protective garment onto a child according to one embodiment of the invention.
[0065] In Block 610 , the arms of the child are place within the pair of sleeves on the protective garment.
[0066] In Block 620 , the upper portion of the protective garment is fastened to the upper body of the child. In one embodiment, a back fastener attaches the protective garment to the child. In another embodiment, fasteners attach the protective garment to the sides of the child. In yet another embodiment, a body fastener attaches the front surface of the protective garment to the front portion of the child. In one embodiment, once attached the upper portion of the protective garment is attached to the child, the upper portion of the child is protected from spills and stains.
[0067] In Block 630 , the legs of the protective garment are attached to the legs of the child. In one embodiment, a leg fastener attaches the protective garment to the child. In one example, the leg fastener attaches a portion of the protective garment with another portion of the protective garment with the child's leg wrapped within the protective garment. In another example, the leg fastener directly attaches the leg portion of the protective garment to the back portion of the child's leg. In another embodiment, leg fastener attaches the protective garment to the sides of the child's leg. In yet another embodiment, a body fastener attaches the front surface of the leg portion of the protective garment to the front portion of the child's leg.
[0068] FIGS. 7A, 7B , and 7 C illustrate exemplary stages of utilizing the garment 100 shown in FIGS. 1 and 2 within the context of the flow diagram shown in FIG. 6 . FIG. 7A shows the sleeves of the garment 100 being placed through the arms of the child. FIG. 7B shows the upper portion of the garment 100 being fastened to the child. FIG. 7C shows the legs of the garment 100 being fastened to the child.
[0069] FIGS. 8A, 8B , and 8 C illustrate exemplary stages of utilizing the garment 400 shown in FIG. 4 within the context of the flow diagram shown in FIG. 6 . FIG. 8A shows the sleeves of the garment 400 being placed around the arms of the child. FIG. 8B shows the upper portion of the garment 400 being fastened to the child. FIG. 8C shows the legs of the garment 400 being fastened to the child.
[0070] FIG. 9 illustrates a patch 900 for use with one embodiment of the methods and apparatuses for protecting a child from spills. The patch 900 is configured to provide extra protection against staining and soiling by preventing localized soiling of the child, the child's clothes, and/or the garments 100 , 300 , and 400 . In one embodiment, the patch 900 includes a fastener 910 and a surface 920 . The fastener 910 is configured to attach to the child, the child's clothes, and/or the garments 100 , 300 , and 400 . In one embodiment, the patch 900 is configured to be utilized in conjunction with the garments 100 , 300 , and 400 as protection in areas not covered by the garments 100 , 300 , and 400 or to provide additional protection to prevent soiling of the garments 100 , 300 , and 400 . In one embodiment, the fastener 910 includes a hook and loop fastener, an adhesive fastener, and a combination thereof.
[0071] FIGS. 10A, 10B , and 10 C illustrate additional embodiments.
[0072] FIG. 10A is a diagram illustrating a back view of a garment 1000 that is another embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 1000 is configured to protect a child's clothes from being soiled. The garment 1000 is also designed to enable a caregiver to easily affix the garment 1000 to the child and to remove the garment 1000 from the child without having any access to the back portion of the child. In one embodiment, the garment 1000 includes the front surface 1001 , a pair of sleeves 1002 , a neck opening 1003 , a pair of legs 1004 , shoulder fasteners 1005 , leg fasteners 1020 , body fasteners 1015 , and arm fasteners 1010 .
[0073] In one embodiment, the neck opening 1003 is configured to accommodate a child's neck. In addition, the shoulder fasteners 1005 securely attaches the neck opening 1003 and upper portion of the garment 1000 to the child's neck and upper body without requiring access to the back portion of the child. In one embodiment, the shoulder fasteners 1005 attach to the front portion of a child's clothing.
[0074] Further, the pair of sleeves 1002 are connected to the front surface 1001 and configured to accept the arms of a child. The pair of legs 1004 are connected to the front surface 1001 and configured to accept the legs of a child.
[0075] In one embodiment, the front surface 1001 is connected to the body fasteners 1015 . The front surface 1001 in conjunction with the body fasteners 1015 are configured to attach the torso portion of the garment 1000 to the torso portion of the child. In one embodiment, the body fasteners 1015 are configured such that the upper portion of the garment 1000 can be attached the child while the child's back is completely obstructed. The body fasteners 1015 are configured to attach to the front surface of the child. In one embodiment, the body fasteners 1015 are configured to attach to the child's clothes.
[0076] In one embodiment, the leg fasteners 1020 are each connected to one of the pair of legs 1004 . In one embodiment, the pair of legs 1004 in conjunction with the leg fasteners 1020 are configured to secure the pair of legs 1004 to the front surface of the child's legs without having any access to the back portion of the child's legs. For example, if the child is strapped into a car seat, the pair of legs 1004 of the garment 1000 can be secured to the legs of the child without having access to the back portion of the child's legs. For example, the leg fasteners 1020 are configured to attach to the front portion of the child's legs.
[0077] In one embodiment, the arm fasteners 1010 are each connected to one of the pair of sleeves 1002 . In one embodiment, the pair of sleeves 1002 in conjunction with the arm fasteners 1010 are configured to secure the pair of sleeves 1002 around the child's arms without having complete access to the back portion of the child's arms. For example, if the child is seated or laying down, the pair of sleeves 1002 of the garment 1000 can be secured to the arms of the child without having complete access to the back portion of the child's arms.
[0078] FIG. 10B is a diagram illustrating a back view of a garment 1030 that is another embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 1030 is configured to protect a child's clothes from being soiled. The garment 1030 is also designed to enable a caregiver to easily affix the garment 1030 to the child and to remove the garment 1030 from the child without having any access to the back portion of the child. In one embodiment, the garment 1000 includes the front surface 1001 , a pair of sleeves 1002 , a neck opening 1003 , a pair of legs 1004 , and a body fastener 1035 . In one embodiment, the body fastener 1035 is configured to attach the garment 1030 to the body of the child.
[0079] FIG. 10C is a diagram illustrating a back view of a garment 1000 that is another embodiment consistent with the methods and apparatuses for protecting a child from spills. The garment 1040 is configured to protect a child's clothes from being soiled. The garment 1040 is also designed to enable a caregiver to easily affix the garment 1040 to the child and to remove the garment 1040 from the child without having any access to the back portion of the child. In one embodiment, the garment 1040 includes the front surface 1041 , a pair of sleeves 1002 , a neck opening 1003 , a pair of legs 1004 , leg fasteners 1060 , body fasteners 1055 , and arm fasteners 1050 .
[0080] Further, the pair of sleeves 1002 are connected to the front surface 1041 and configured to accept the arms of a child. The pair of legs 1004 are connected to the front surface 1041 and configured to accept the legs of a child.
[0081] In one embodiment, the front surface 1041 is connected to the body fasteners 1055 . The front surface 1041 in conjunction with the body fasteners 1055 are configured to attach the torso portion of the garment 1040 to the torso portion of the child. In one embodiment, the body fasteners 1055 are configured such that the upper portion of the garment 1040 can be attached the child while the child's back is completely obstructed. The body fasteners 1055 are configured to attach to the front surface of the child. In one embodiment, the body fasteners 1055 are configured to attach to the child's clothes.
[0082] In one embodiment, the leg fasteners 1060 are each connected to one of the pair of legs 1004 . In one embodiment, the pair of legs 1004 in conjunction with the leg fasteners 1060 are configured to secure the pair of legs 1004 to the front surface of the child's legs without having any access to the back portion of the child's legs. For example, if the child is strapped into a car seat, the pair of legs 1004 of the garment 1040 can be secured to the legs of the child without having access to the back portion of the child's legs. For example, the leg fasteners 1060 are configured to attach to the front portion of the child's legs.
[0083] In one embodiment, the arm fasteners 1050 are each connected to one of the pair of sleeves 1002 . In one embodiment, the pair of sleeves 1002 in conjunction with the arm fasteners 1050 are configured to secure the pair of sleeves 1002 around the child's arms without having complete access to the back portion of the child's arms. For example, if the child is seated or laying down, the pair of sleeves 1002 of the garment 1040 can be secured to the arms of the child without having complete access to the back portion of the child's arms.
[0084] The foregoing descriptions of specific embodiments of the invention have been presented for purposes of illustration and description. The invention may be applied to a variety of other applications.
[0085] They are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed, and naturally many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.
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In one embodiment, the methods and apparatuses include a shell surface comprising: a front portion having a continuous surface for protecting a user from contamination, wherein the continuous surface provides a barrier between the contamination and the user, wherein the front portion protects a chest and abdomen area of the user from the contamination; an arm portion connected to the front portion, wherein the arm portion protects the arm from contamination; and a leg portion connected to the front portion, wherein the leg portion is configured to protect a leg of the user; a first fastener coupled to the leg portion for fastening the leg portion around the leg of the user; and a second fastener coupled to the front portion for fastening the front portion to the user wherein the second fastener is configured to attach the front portion to a side portion of the user, wherein the shell surface is configured to attach to the user through the first fastener and the second fastener while a portion of a back of the user is blocked.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 11/338,827 filed Jan. 25, 2006, now abandoned, which is a continuation of Ser. No. 10/231,334, filed 08/30/2002, now U.S. Pat. No. 7,028,484 which issued Apr. 18, 2006, the specifications of both which are incorporated herein by reference.
TECHNICAL FIELD
The present invention relates generally to gas turbine engines, and more particularly to a nested channel configuration for use in fuel manifolds, nozzle stems and the like.
BACKGROUND OF THE INVENTION
Fuel nozzles which supply fuel to a combustion chamber in a gas turbine engine are well known in the art. Generally, a plurality of circumferentially distributed fuel nozzles forming a nozzle array in the combustion chamber are used to ensure sufficient distribution of the fuel. The fuel nozzle array typically comprises a plurality of injector tip assemblies for atomizing fuel into the combustion chamber, the injector tips being connected to an outer fuel manifold via nozzle stems.
Some conventional nozzle systems define duel adjacent fuel passages, sometimes concentrically disposed within an outer tube. In an effort to provide a dual passage stem member which is relatively simpler and more economical to manufacture, it is also known to use a stem comprised of a solid piece of material having adjacent slotted fuel conduits. The distinct slots, formed side by side, define primary and secondary fuel conduits extending between the inlet and outlet of the nozzle stem, and are sealed by a brazed cover plate.
Prior art multiple channel systems are cumbersome, difficult to manufacture and maintain, and heavy. Accordingly, improvements are desirable.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved fuel injection system that is simpler and more economical to manufacture.
It is a further object of the present invention to provide a fuel injection system that, among other things, eliminates the need for multiple independent fuel manifolds and for complex fuel nozzle stems.
Therefore, in accordance with the present invention, there is provided a gas turbine engine fuel nozzle having a spray tip assembly in flow communication with a fuel source, the fuel nozzle comprising: a fuel-conveying member comprising a stepped channel formed in a surface of the fuel-conveying member for providing fuel flow to the spray tip assembly; at least a first inner sealing plate being disposed within the stepped channel and, dividing the stepped channel into at least a primary and a secondary discrete nested conduit; and an outer sealing plate being engaged with the surface for enclosing the stepped channel; whereby each discrete nested conduit is adapted for directing an independent fuel flow from the fuel source to the spray tip assembly.
There is also provided, in accordance with the present invention, a method of manufacturing a gas turbine engine fuel nozzle having multiple discrete fuel conduits for directing independent fuel flows from a fuel source to a spray tip assembly, the method comprising: providing a fuel-conveying member formed from a single solid piece of material; machining a single stepped channel in a surface of the fuel-conveying member, the stepped channel defining at least primary and secondary nested slots, the secondary slot defining a larger cross-sectional area than the primary slot and being immediately open to the surface; fixing at least a first inner sealing plate having a width greater than a width of the primary slot, within the secondary slot with the first inner sealing plate abutting a shoulder formed by the stepped channel, thereby dividing the stepped channel into a primary discrete nested fuel conduit and the nested secondary slot; and fixing an outer channel sealing plate to the fuel-conveying member to enclose the secondary slot thereby forming a secondary discrete nested fuel conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:
FIG. 1 is a cross-sectional view of a gas turbine engine comprising a fuel injection system according to the present invention.
FIG. 2 is a perspective view of a first embodiment of a fuel injection system according to the present invention comprising an annular, nested channel fuel manifold ring.
FIG. 3 is a cross-sectional view of the nested channel fuel manifold ring of FIG. 2 .
FIG. 4 is a cross-sectional view of an alternate fuel manifold ring having an additional nested channel.
FIG. 5 is a perspective view of a second embodiment of a fuel injection system according to the present invention comprising a fuel nozzle stem having nested fuel channels formed therein.
FIG. 6 is a cross-sectional view of the nested channel fuel nozzle stem of FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a gas turbine engine 10 generally comprising, in serial flow communication, a fan 12 through which ambient air is propelled, a multistage compressor section 14 for pressurizing the air, a combustion section 16 in which the compressed air is mixed with fuel atomized into a combustion chamber 17 by a fuel injection system comprising a fuel injection nozzle assembly 2 Q, the mixture being subsequently ignited for generating hot combustion gases before passing through a turbine section 18 for extracting energy from the combustion gases.
Referring to FIG. 2 , the fuel injection nozzle assembly 20 comprises an annular fuel manifold ring 22 generally disposed within the combustion chamber 17 of the engine, and mounted via several integral attachment lugs 28 for fixing the annular ring 22 to an appropriate support structure. The annular fuel manifold ring 22 comprises a plurality of fuel injector spray tip assemblies 24 thereon, which atomize the fuel for combustion. The exterior of the annular ring 22 comprises an outer heat shield 26 covering the ring. This provides the fuel manifold ring thermal protection from the high temperature environment of the combustion chamber. A primary fuel inlet pipe 30 and a secondary fuel inlet pipe 32 provide dual, independent fuel feeds to the manifold, which distributes the two fuel supplies to the spray tip assemblies. The spray tip assemblies 24 are directly mounted to the annular fuel manifold ring, without requiring conventionally used nozzle stems which are traditionally required to link, in fluid flow communication, the spray tip assemblies with each distinct fuel manifold for each fuel inlet source. The above features are generally known in the art.
Referring now to FIG. 3 more clearly showing the details of the fuel injection nozzle assembly 20 according to the present invention, the annular fuel manifold ring 22 is preferably formed from a single solid piece of material and comprises a single stepped channel 36 formed in an outer peripheral surface 38 of the manifold ring which is covered by a protective outer heat shield 26 . The stepped channel 36 is preferably formed by a single machining operation, for example by a single milling or routing step using a multi-diametered bit of a predetermined size to create the number and size of the nested slots comprising the entire stepped channel 36 . Once provided, as described below, the nested slots, defined by the stepped slot that is machined, or otherwise formed, in the fuel manifold ring, create annular fuel galleries which permit circumferential distribution of independently controllable fuel supplies to be fed to each spray tip assembly. The channel 36 has a length which is defined as the circumferential length or circumference of the channel.
The annular stepped channel 36 comprises at least two nested fuel conduits; namely a primary nested fuel conduit 40 and secondary nested fuel conduit 42 . The annular primary fuel conduit is located in the manifold ring closest to the spray tip assemblies, and preferably (to facilitate manufacture) is much smaller in cross-sectional area than the annular secondary nested fuel conduit 42 , which opens immediately to the peripheral surface 38 in which the stepped channel 36 is formed. A first inner sealing member or plate 44 , sized such that it fits within the secondary conduit portion of the stepped channel and is larger than the width of the primary conduit (i.e. to seal it), is fixed against a first shoulder 43 formed in the stepped channel between the primary and secondary nested conduits, by way of brazing or, another fastening/sealing method. The first inner sealing plate 44 for the annular fuel manifold ring 22 , is preferably also an annular ring plate, substantially extending around the full circumference of manifold ring. An outer stepped channel sealing member or plate 46 is similarly fixed to the fuel manifold ring 22 by brazing or other similar fastening method, against a second shoulder 45 formed within the stepped channel for receiving the annular outer sealing plate ring 46 abutted therein. The outer sealing ring plate 46 could also be brazed directly to the outer peripheral surface 38 of the manifold ring, without the need for the second shoulder 45 in the stepped channel 36 . The two sealing plates thereby divide the single stepped channel 36 into two discrete, nested fuel conduits that are sealed from one another and which can supply independent fuel supplies to the spray tip assemblies, primary nested fuel conduit 40 and secondary nested fuel conduit 42 . This therefore permits the use of a single-piece fuel manifold, having at least two discrete fuel galleries formed therein in a simple and cost effective manner. This eliminates the need for employing fuel nozzle stems and conventional fuel nozzle injector arrays comprising hundreds of sub-components merely to connect an exteriorly located fuel manifold to the spray tip assemblies in the combustion chamber.
The primary and secondary annular nested fuel conduits 40 and 42 permit circumferential distribution of the primary and secondary fuel supply around the fuel manifold ring. At the location of each spray tip assembly 24 mounted to the annular manifold ring 22 , fuel outlet passage holes are formed, by drilling or otherwise, in the manifold ring body substantially perpendicularly to the outer peripheral surface 38 , to enable fluid flow communication between the nested fuel conduits and the spray tip assembly 24 . Specifically, primary fuel conduit outlet passage 48 permits primary fuel flow from the primary fuel conduit 40 to be fed into the primary distributor 54 of the spray tip assembly, and secondary fuel conduit outlet passage 50 permits secondary fuel flow from the secondary fuel conduit 42 to be fed into the annular secondary fuel swirling cavity 63 of the spray tip assembly 24 .
Such spray tip assemblies typically also comprise a valve member 52 disposed within the primary distributor 54 for regulating primary fuel flow through a primary cone 56 , protected by a primary heat shield 58 , before being ejected by a primary fuel nozzle tip 59 . A secondary fuel swirler 60 disposed substantially concentrically about the primary distributor, comprises an annular secondary fuel swirling cavity, which swirls the secondary fuel flow before it is ejected through annular secondary fuel nozzle tip 61 . An outer air swirler 62 comprises a plurality of circumferentially spaced air passages 64 which convey air flow for blending with the primary and secondary fuel sprays issuing from the primary and secondary spray orifices, 59 and 61 respectively, of the spray tip assembly.
Referring to FIG. 4 , this embodiment of an annular fuel manifold ring 122 comprises an alternately-shaped stepped channel 136 machined in the solid, one-piece material of the manifold ring. The stepped channel 136 comprises an additional or auxiliary channel 172 , therein. As above, a primary nested fuel conduit 140 is formed by fixing the first inner annular sealing member or plate 144 against a first shoulder 143 , thereby dividing the primary fuel conduit 140 from the secondary nested fuel conduit 142 . The secondary nested fuel conduit 142 is enclosed by a Second inner sealing member or plate 170 abutted with, and fixed against, second shoulder 145 within the stepped channel 136 . As described above, although several attachment and sealing methods for fixing the sealing plates to the manifold ring can be used, they are preferably brazed thereto. The annular auxiliary channel 172 is further axially enclosed by an outer sealing member or plate 146 , fixed against the outer peripheral surface 138 of the annular fuel manifold ring 122 . As described, above, a primary conduit outlet passage 148 and a secondary conduit outlet passage 150 , formed in the manifold ring perpendicularly to the outer peripheral surface 138 at predetermined circumferential locations of the manifold ring corresponding to location of the spray tip assemblies, provide dual independent fuel feeds to each spray tip assembly.
The auxiliary channel 172 can be used to carry a coolant, such as for example recirculated fuel, which will draw heat from the ring. The coolant flow in the auxiliary channel 172 is independent of the quantity of fuel being delivered to the engine. This is particularly needed during low power operation, when less fuel flows through the conduits of the manifold, and therefore more heat is absorbed from the combustion chamber by the entire manifold ring. This reduces fuel coking within the fuel manifold, which can occur if sufficient fuel flow is not maintained to cool the manifold ring. Each conduit, namely the primary fuel conduit 140 , the secondary fuel conduit 142 and the auxiliary cooling conduit 172 , each has its own inlet feed line, such that the fuel rates and the coolant flow rate can be independently controlled. Independent control of the primary and secondary fuel flows and independent feeding of each spray tip from the annular conduits providing circumferential fuel distribution, also permits fuel staging, wherein specific amounts of fuel are partitioned to specific circumferential locations of the combustion chamber to enhance ignition or to control emissions.
The present invention may also be used to provide multiple nested channels for providing discrete fuel conduits in a fuel nozzle stem.
Referring to FIG. 5 and FIG. 6 , a fuel nozzle stem 200 comprises a central stem body 202 and a stem inlet end 204 and a stem outlet end 206 . A stepped channel 236 is formed in a first outer surface 238 of the stem body 202 . The channel is divided by an inner sealing member or plate 244 , abutted with, and preferably brazed to, shoulder 243 within the stepped channel, thereby defining a primary nested fuel conduit 240 and a preferably larger secondary nested fuel conduit 242 . Unlike, the nested fuel conduits described previously, the primary and secondary conduits 240 and 242 are substantially linear, rather than being annular. Therefore, the channel 236 has a length which is defined as the linear or longitudinal length of the channel. The secondary nested fuel conduit 242 is enclosed by an outer sealing member or plate 246 , preferably fixed to the outer surface 238 of the stem body, again preferably by brazing. The primary and secondary fuel conduits thereby provide discrete fuel flow passages between the inlet end 204 and the outlet end 206 of the stem, which are adapted to be engaged with a fuel manifold adapter and a nozzle spray tip assembly, respectively. This permits at least two discrete fuel flows through the nozzle stem to a spray tip assembly. Typically, the entire fuel nozzle stem 200 is fitted within a surrounding cylindrical outer shield 278 , which is can be brazed to the stem member to provide an element of heat protection. The stem body 202 can also comprise auxiliary cooling channels 272 formed therein according to the present invention. In the example shown, the auxiliary cooling channels 272 are on opposing sides of the stem body in outer lateral surfaces 280 of the stem body, substantially perpendicular to the first outer surface 238 with the stepped channel 236 formed therein. Auxiliary channel outer sealing plates 273 enclose the auxiliary cooling channels. The two opposing auxiliary coolant channels 272 are in fluid flow communication at the outlet end 206 of the stem, such that they can provide inlet and outlet passages for coolant flowing through to stem to provide cooling thereof.
While the above description constitutes the preferred embodiments, it will be appreciated that the present invention is susceptible to modification and change without departing from the fair meaning of the accompanying claims. For example, the present invention can offer reliability and weight benefits in any gas turbine engine application wherever multiple hydraulic or other fluid conduits are required or desired. Also, the stepped construction of the channel is preferred, but other configurations will be apparent to those skilled in the art. Still other modifications and applications beyond those described will be apparent to those skilled in the art.
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A multiple conduit system for a gas turbine engine, the multiple conduit system extending between a plurality of conduit inlet and outlets. A channel, adapted for conveying fuel flow, is formed in a surface of a gas turbine engine component. The channel includes at least a first discrete conduit and a second discrete conduit. The first and second discrete conduits are each adapted to direct an independent fluid flow from respective inlets to respective outlets.
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FIELD OF THE INVENTION
The field of this invention is cardiac bypass surgery.
BACKGROUND OF THE INVENTION
During cardiac surgery for procedures such as coronary artery bypass grafting, heart valve repair or replacement, septal defect repair, pulmonary thrombectomy, atherectomy, aneurysm repair, aortic dissection repair and correction of congenital defects, cardiopulmonary bypass and cold cardiac ischemic arrest are often required. Typically, a cooled cardioplegia solution, a solution containing elevated levels of potassium, for example, is administered in the antegrade direction (in the direction of normal blood flow) through the patient's aorta and into the coronary arteries. The cold (2 to 3 degrees centigrade) cardioplegia solution stops the heart from beating and reduces its temperature to minimize damage to the heart during surgery. Cardiopulmonary bypass maintains the peripheral circulation of oxygenated blood to all body organs except the heart during the period of cold, cardioplegic, ischemic arrest.
For some patients, such as those suffering from critical coronary artery stenosis and aortic valve disease, antegrade perfusion may be difficult, inefficient and incomplete. Retrograde (in the direction opposite of normal blood flow) cardioplegia, using current technology, may be administered via the coronary sinus into the coronary circulation.
Currently surgeons performing cardiac bypass surgery use one or more cannulae for venous drainage and additional cannulae for retrograde perfusion. The multiple cannulae are obstacles and restrict visibility in the surgical arena. Placement of the cardioplegia cannula into the coronary sinus is a semi-blind procedure performed through an additional purse-string suture-closed access port via the right atrium. The retrograde cannula may be improperly positioned within the coronary sinus, which results in critical coronary vessels being inadequately perfused.
New devices and methods are needed, which facilitate cold cardioplegic arrest, yet limit the number of cannulae required to isolate the heart and coronary blood vessels from the peripheral vasculature, arrest the heart, protect all the coronary blood vessels, and drain venous blood from the inferior and superior vena cava.
SUMMARY OF THE INVENTION
This invention relates to a balloon, or tourniqueted, catheter or cannula useful in the retrograde administration of cardioplegia through the coronary sinus and simultaneous venous drainage during cardiac bypass surgery without the need to cannulate the coronary sinus.
The present invention is a cannula for performing venous drainage and retrograde perfusion of the heart during cardiac bypass surgery. A single multi-lumen cannula of the present invention can perform the same function as multiple cannulae. The cannula of the invention for cardioplegic administration can improve the protection of a heart during periods of ischemia such as occurs during open-heart surgery.
The present invention is a multi-lumen cannula with superior and inferior vena cava occlusion structures, cardioplegia infusion and drainage ports, a pressure monitoring port, and venous drainage ports. Typical occlusion structures may include balloons, umbrellas, or externally applied tourniquets. The preferred occlusion structures are balloons constructed of elastomeric materials.
A first lumen of the cannula is connected to the cardioplegia infusion system and provides cardioplegia solution to arrest the heart. A second cannula lumen is connected to the venous drainage system. The drainage ports are located in the second lumen. A third lumen is connected to the balloon inflation system, which provides inflation fluids, such as water, isotonic saline or cardioplegia solution, under controlled pressure or volume to inflate the balloons. The pressure of the balloons and right atrium may also be monitored through additional lumens. The balloons isolate the heart from the peripheral vasculature by occluding the inferior and superior vena cava just proximal to the right atrium. Additional lumens may be utilized for inflation of multiple balloons, pressure monitoring, flow monitoring, drainage of cardioplegia, fluid and drug infusion and the like. Since it is useful to measure cardioplegic perfusion pressure, a pressure transducer or pressure measuring lumen may be provided at or near the distal end of the cardioplegia perfusion lumen for this purpose.
The cannula is placed into the vena cava via a route through the internal jugular vein, cranial vena cava or brachial vein. A smaller diameter cannula could be placed through smaller venous access ports. The use of smaller venous access ports could be enabled by use of a pump or vacuum powered venous drainage system, typically external to the cannula. The catheter of the present invention combines the functions of several catheters currently used in cardiac surgery. This facilitates the surgery and improves the surgical field because extra cannulae do not obstruct the operative field. The number of individual catheters is reduced, providing a more cost effective method for cardiac surgery. Most importantly, improved cardiac protection is achieved compared to that of standard retrograde perfusion cannulae.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a longitudinal cross-section of the cannula of the present invention comprising a distal tip, a proximal end, and a connecting tube according to aspects of an embodiment of the invention. External systems provide for venous drainage, cardioplegia infusion, and balloon inflation.
FIG. 2 illustrates a lateral cross-section of a multi-lumen tube for construction of the cannula according to aspects of an embodiment of the invention.
FIG. 3 illustrates, in detail, a longitudinal cross-section of the distal tip of the cannula of FIG. 1 according to aspects of an embodiment of the invention.
FIG. 4 illustrates, in detail, a longitudinal cross-section of the proximal end of the cannula of FIG. 1 according to aspects of an embodiment of the invention.
FIG. 5 shows the placement of the cannula of the present invention in the heart for venous drainage and retrograde perfusion according to aspects of an embodiment of the invention.
FIG. 6 illustrates, in exterior view, another embodiment of the cannula comprising multiple balloons to accommodate various anatomic differences according to aspects of an embodiment of the invention. Cutouts on the balloons show features on the cannula surface that would normally be hidden by the balloons.
FIG. 7 illustrates a lateral cross-section of a multi-lumen tubing for construction of the cannula of FIG. 6 according to aspects of an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a catheter, tube or cannula 10 of the present invention connected to a cardioplegia infusion system or set 12 , a venous drainage collection system 14 and an occlusion enabling system 16 . In this preferred embodiment, the occlusion enabling system 16 is a balloon inflation system. The catheter 10 comprises a distal tip 18 , a proximal end 20 , and a length of multi-lumen connection tubing 22 . The proximal end 20 comprises a manifold or hub 23 . The manifold 23 comprises a cardioplegia infusion adapter or fitting 24 , a venous drainage collection adapter or fitting 26 , and an occlusion adapter 28 . In this preferred embodiment, the occlusion adapter 28 is a balloon inflation adapter or luer fitting. The manifold 23 is typically molded from polymer, such as polyvinyl chloride, polycarbonate, or the like.
The cardioplegia infusion adapter 24 is connected to the cardioplegia infusion system 12 . The cardioplegia infusion adapter 24 may be any fluid-tight fitting, such as a luer fitting, suitable for use with the cardioplegia infusion set 12 . The standard cardioplegia system 12 generally comprises a pressurized or non-pressurized bag of cardioplegia solution, a roller pump, a length of tubing and a plurality of connectors. Standard cardioplegia solutions include water, electrolytes such as but not limited to potassium, crystalloid solutions, and blood.
The venous drainage collection adapter 26 is connected to the venous drainage collection system 14 . The drainage collection adapter 26 is typically larger in diameter than the balloon inflation fitting 28 or cardioplegia infusion fitting 24 . The drainage collection adapter 26 should be capable of being connected to the gravity fed, pump driven or vacuum fed drainage system 14 and is most typically a ⅜ inch to ½ inch diameter hose barb. Standard venous drainage systems 14 generally comprise a connector, a length of tubing and a venous reservoir. Optionally, a vacuum pump may be connected to the venous reservoir.
The balloon inflation adapter 28 is connected to the balloon inflation system 16 . The balloon inflation adapter 28 is typically a female luer fitting but may be any fluid-tight fitting suitable for use with an inflation syringe or the like. The standard balloon inflation system 16 comprises a syringe, a volume of balloon inflation fluid such as saline or radiopaque media, and a valve or stopcock associated with each balloon inflation adapter 28 . Additionally, the balloon inflation system 16 could comprise a device, such as a jackscrew, to advance or withdraw a plunger on the syringe using mechanical advantage.
FIG. 2 shows the cross-section of the connection tubing 22 . The connection tubing 22 is multi-lumen tubing and comprises, at minimum, an infusion lumen 30 , a venous drainage lumen 32 , an inflation lumen 34 , and a wall 31 . The connection tubing 22 is preferably made from a polymeric material such as polyvinyl chloride, polyethylene, polypropylene, polyurethane and the like. Preferably, the tubing 22 is transparent.
FIG. 3 illustrates the distal tip 18 of the catheter 10 of FIG. 1 in detail. The distal tip 18 is an extension of the connecting tubing 22 and comprises the infusion lumen 30 , the venous drainage lumen 32 and the inflation lumen 34 . Additionally, the distal tip 18 comprises a plurality of venous drainage ports 36 , a distal or first occlusion device 39 , a plurality of cardioplegia infusion port or ports 42 , and a proximal or second occlusion device 45 . The distal tip 18 further comprises an inflation lumen plug 48 and an infusion lumen plug 50 . A cardioplegic drainage lumen may likewise be utilized to adjust cardioplegic perfusion pressures, if needed.
In this preferred embodiment, the first occlusion device 39 comprises a first balloon 38 and a plurality of first balloon inflation ports 40 . The second occlusion device 45 comprises a second balloon 44 and a plurality of second balloon inflation ports 46 .
The venous drainage ports 36 are openings in the drainage lumen 32 and connect the venous drainage lumen 32 with the exterior of the cannula 10 . There is no communication between the venous drainage lumen 32 and the other cannula lumens 30 and 34 . The venous drainage ports 36 are preferably located more proximally than the second balloon 44 and/or more distally than the first balloon 38 on the cannula 10 .
The balloon inflation ports 40 and 46 are located on the inflation lumen 34 . The inflation lumen 34 is isolated from the other cannula lumens 30 and 32 . The first balloon 38 and the second balloon 44 are located over the first balloon inflation ports 40 and the second balloon inflation ports 46 , respectively. When the balloon inflation fluid flows through the inflation ports 40 and 46 from the inflation lumen 34 , the balloons 38 and 44 inflate.
The cardioplegia infusion port(s) 42 are openings on the infusion lumen 30 . The infusion lumen 30 is isolated from the other lumens 32 and 34 . The cardioplegia infusion ports 42 are located between the balloons 38 and 44 such that cardioplegia solution is infused between the balloons 38 and 44 and is directed into the right atrium of the heart where it subsequently passes into the coronary arteries by way of the coronary sinus.
FIG. 4 shows the proximal end 20 of the cannula 10 of FIG. 1 in detail. The proximal end 20 is an extension of the connecting tube 22 and comprises the cardioplegic infusion lumen 30 , the venous drainage lumen 32 , and the inflation lumen 34 . The proximal end 20 additionally comprises the manifold 23 , which comprises the cardioplegia infusion adapter 24 , the venous drainage collection adapter 26 and the balloon inflation adapter 28 . The cardioplegia infusion adapter 24 connects to the infusion lumen 30 . The venous drainage collection adapter 26 connects to the drainage lumen 32 and the balloon inflation adapter 28 connects to the inflation lumen 34 .
FIG. 5 illustrates the placement of the cannula 10 of the present invention in a heart 100 during retrograde perfusion. The heart 100 comprises a left ventricle 102 , a right ventricle 104 , a tricuspid valve 106 , a coronary sinus 108 , a right atrium 110 , an inferior vena cava 112 , and a superior vena cava 114 .
During normal operation of the heart, blood returning from the tissues of the body passes through peripheral veins into the superior 114 and inferior vena cava 112 and into the right atrium 110 . The coronary sinus 108 is the region of the heart 100 where blood exits the coronary vascular circuit and passes back into the right atrium 110 . The coronary sinus 108 is located in close proximity to the inferior vena cava's entry into the right atrium 110 . Blood leaving the coronary circulation by way of the coronary sinus 108 joins the venous blood from the vena cava 112 and 114 in the right atrium 110 . The venous blood flows through the right atrium 110 and is pumped by the right ventricle 104 into the lungs where it is oxygenated and carbon dioxide is removed. The oxygen-rich blood then passes into the left atrium and left ventricle 102 where it is then pumped into the systemic circulation to nourish the organs and tissues of the body. The coronary ostea, or entrance to the coronary arteries, are located at the root of the aorta, just downstream of the aortic valve.
When the heart 100 is placed on cardiopulmonary bypass, blood is removed from the venous circulation at the inferior vena cava 112 and superior vena cava 114 and is routed to an oxygenator that adds oxygen and removes carbon dioxide. The oxygenated blood is pumped back into the patients systemic circulation so tissues can be perfused while the heart is being surgically repaired.
The cannula 10 of the present invention serves the triple function of blocking venous blood from entering the right heart during surgery, removing the venous blood from the vena cava so that it may be extracorporeally oxygenated and pumped back to the patient, and infusing cardioplegia solution into the heart in a retrograde direction during the surgical repair procedure.
Referring to FIGS. 1 , 3 , 4 , and 5 , the physician makes an incision in the jugular vein, for example, and inserts the distal tip 18 of the catheter or cannula 10 into the incision. The catheter 10 is threaded into the vein, advanced into the vena cava 112 and 114 , and positioned, with the aid of fluoroscopy, for example, such that the balloons 38 and 44 are located in the inferior vena cava 112 and superior vena cava 114 , respectively. The cardioplegia infusion ports 42 are located at the entrance to, or inside of, the right atrium 110 and the drainage ports 36 are located in the superior vena cava 114 and inferior vena cava 112 , proximal or upstream of the balloons 38 and 44 .
Next, the balloon inflation system 16 is activated. Balloon inflation is accomplished by driving balloon inflation fluid from the balloon inflation system 16 , through the balloon inflation adapter 28 , into the balloon inflation lumen 34 , through the balloon inflation ports 40 and 46 and into the balloons 38 and 44 . The inflation lumen plug 48 prevents the balloon inflation fluid from escaping from the distal end of the inflation lumen 34 . This infusion of balloon inflation fluid causes the balloons 38 and 44 to inflate and occlude the entrance of the right atrium 110 from the superior vena cava 114 and the inferior vena cava 112 . Because of this occlusion, blood is prevented from flowing from the superior vena cava 114 and the inferior vena cava 112 into the right atrium 110 of the heart 100 , and must exit via the drainage ports 36 of the cannula 10 . The blood passes through the cannula 10 and on into the venous reservoir of the cardiopulmonary bypass system.
The cardioplegia infusion system 12 is next activated. The cardioplegia solution flows from the cardioplegia infusion system 12 , through the cardioplegia infusion adapter 24 , into the infusion lumen 30 , through the cardioplegia infusion ports 42 , and into the right atrium 110 where, under moderate pressure, the cardioplegia solution enters the coronary sinus 108 and the right ventricle 104 . In order for cardioplegic solution to enter the coronary sinus 108 in a retrograde fashion, the right atrium 110 and ventricle 104 must be pressurized, which necessitates occlusion of the pulmonary artery root. The pulmonary artery thus is typically cross-clamped to prevent perfusion of the lungs during surgery. The infusion lumen plug 50 prevents the cardioplegia solution from escaping from the distal end of the infusion lumen 30 . The cardioplegia solution arrests the beating of the heart 100 by interfering with the sodium potassium cycle of the cardiac muscle cells.
In addition, the venous drainage collection system 14 is activated. Any blood in the superior vena cava 114 and inferior vena cava 112 flows through the drainage ports 36 , into the drainage lumen 32 , through the drainage collection adapter 26 , and into the drainage collection system 14 . The drainage collection system 14 collects the venous blood. This blood is, in most cases, routed to a venous reservoir of a cardiopulmonary bypass system where it then passes into an oxygenator and heat exchanger where it, respectively, undergoes removal of carbon dioxide and addition of oxygen and undergoes heat transfer. The oxygenated blood is pumped back into the patient's systemic circulation via an arterial cannula placed in a systemic artery distal to the aortic valve.
The surgeon can now perform the prescribed heart surgery. A single cannula of the present invention provides the infusion, inflation, and drainage functions, which eliminates the need for the multiple cannulae currently used for open-heart procedures.
Referring to FIG. 5, patients have different spacing between the entrance of the inferior vena cava 112 into the right atrium 110 and the entrance of the superior vena cava 114 into the right atrium 110 . A one-size-fits-all catheter 10 may not be optimum for use in all patients. FIG. 6 shows a more preferred embodiment of the catheter, which compensates for anatomic differences between patients. The operation of cardioplegia infusion and drainage collection are the same as that described earlier for the cannula 10 .
Referring to FIG. 6, the catheter or cannula 52 comprises a plurality of first balloons 54 , a second balloon 56 , a plurality of first balloon inflation port sets 58 , a plurality of second balloon inflation ports 60 , and a length of connecting tubing 62 . The catheter 52 also comprises a manifold 64 , which comprises a plurality of first balloon inflation adapters 66 and a second balloon inflation adapter 68 . The catheter is connected to the cardioplegia infusion system 12 , the venous drainage collection system 14 , and the balloon inflation system 16 .
FIG. 7 illustrates a cross section of multi-lumen connection tubing 62 for the construction of the catheter 52 of FIG. 6 . The tubing 62 comprises a plurality of first balloon inflation lumen 70 , a second balloon inflation lumen 72 , the infusion lumen 30 , the drainage lumen 32 , and the wall 31 .
Referring to FIGS. 6 and 7, the balloon inflation system 16 connects to the catheter 52 through the first balloon inflation adapters 66 and the second balloon inflation adapter 68 . Each first balloon inflation adapter 66 connects to one first balloon inflation lumen 70 . The second balloon inflation adapter 68 connects to the second balloon inflation lumen 72 . Each set of first balloon inflation ports 58 is located on one first balloon inflation lumen 66 . The second balloon inflation ports 60 are located on the second balloon inflation lumen 72 . Each first balloon 54 is positioned over one set of first balloon inflation ports 58 , such that when inflation fluid is injected through the selected first balloon inflation ports 58 , only the first balloon 54 over the selected first balloon inflation ports 58 is inflated. The second balloon 56 is positioned over the second balloon inflation ports 60 such that when balloon inflation fluid is injected through the second balloon inflation ports 60 , the second balloon 56 is inflated. Each first balloon inflation adapter 66 has a corresponding first balloon inflation lumen 70 , a corresponding set of first balloon inflation ports 58 , and a corresponding first balloon 54 .
Referring to FIGS. 5 and 6, the physician places the catheter 52 into the right atrium 110 . The physician places the second balloon 56 in the entrance of the superior vena cava 114 and the series of first balloons 54 line up in the right atrium 110 and into the inferior vena cava 112 . The second balloon 56 is inflated to occlude the superior vena cava 114 . Only the first balloon 54 in the plurality of first balloons 54 , which is in the entrance of the inferior vena cava 112 , corresponding to the correct spacing for the patient's heart, is inflated to occlude the inferior vena cava 112 . Balloons 54 and 56 to be inflated are connected to the balloon inflation system 16 through their balloon inflation lumen 70 and 72 . The balloon inflation lumen 70 of the balloons 54 selected for non-inflation are simply not connected to the balloon inflation system 16 . In this manner, the catheter 52 is optimized for the individual patient's anatomy. The better fit minimizes the chance of the balloons 54 and 56 slipping out of position and leaking venous blood into the heart, with potentially severe complications for the surgery patient.
Preferably, the plurality of balloons are located on the distal end of the catheter's cardioplegia infusion ports 42 , although multiple balloons proximal to the cardioplegia inflation ports 42 would also be acceptable. Only the balloons that are spaced correctly to occlude the patient's superior 114 and inferior 112 vena cava are inflated.
In another embodiment for multiple balloon inflation selection, a single balloon inflation lumen may be connected to all of the balloons and to a control rod that selectively opens balloon inflation ports to the correct balloon or balloons. Such a control rod would typically be an axially elongate, torqueable structure running the length of the cannula tubing. By rotating or axially moving the control rod by grasping a projection at the proximal end of the cannula, inflation ports would be selectively opened between the balloon inflation lumen and the balloon to be inflated. Markings on the control rod would indicate which balloons were being inflated or which spacing was being chosen. Again, only the balloons correctly spaced to occlude the patient's vena cava are inflated. Other balloons would not be inflated because their ports would not have been selectively opened.
In yet another embodiment of the cannula 10 , the distal tip 18 comprises an accordion-like or telescoping structure between the occlusion devices 39 and 45 , and a control rod. The accordion-like or telescoping structure allows the length of the cannula 10 to be adjusted so that the occlusion devices 39 and 45 fit the spacing between the patient's superior vena cava 114 and inferior vena cava 112 . This accordion-like structure is a longitudinally flexible area of the cannula 10 with corrugations to allow for compression or expansion in length. The control rod extends from the distal tip 18 of the cannula 10 to the proximal end 20 . The control rod is linked to the cannula 10 such that pushing or pulling the control rod relative to the proximal end 20 increases or decreases the length of the cannula 10 . The control rod is locked into place with a locking device when the correct spacing between the occlusion devices 39 and 45 is achieved. A telescoping structure could be used in place of the accordion-like structure to allow for cannula length adjustment using the control rod.
In yet another embodiment, the balloon inflation adapter 28 is connected to the cardioplegia infusion system 12 . In this embodiment, the cardioplegia solution is used in the cardioplegia infusion system 12 to arrest the heart and in the balloon inflation system 16 to inflate the balloons 38 and 44 or 54 and 56 . Typically, cardioplegia solution is infused at a pressure of around 20 mmHg. The balloons 38 , 44 , 54 , and 56 may be inflated with an internal pressure of 20 mmHg and this pressure may be derived from the pressure of the cardioplegia solution. This embodiment has the advantage of reduced complexity and simplified pressure limiting.
The balloons 38 and 44 are only one way of occluding the vena cava 112 and 114 . Another embodiment of the occlusive structures 39 and 45 comprises one or more external tourniquets. One or more tourniquets may be applied external to the vena cava 112 and 114 to seal the vena cava 112 and 114 to the cannula 10 and prevent cardioplegia solution from escaping the environs of the right atrium entry 110 to the coronary sinus 108 .
A further embodiment of the occlusive structures 39 and 45 comprises umbrella mechanisms, which open up to occlude the vena cava. Opening and closing of the umbrellas would be accomplished using a control rod extending along the length of the catheter and out the proximal end of the catheter where it could be grasped.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims rather than the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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A system is disclosed for cannulating the vena cava of a patient during cardiopulmonary bypass procedures. Such cannulation is necessary for drainage of venous blood from the patient so that it may be oxygenated and pumped back to the patient to perfuse tissues during cardiac surgery and, more specifically, during periods of ischemic cardiac arrest or dysfunction. The device of the present invention not only provides venous drainage for cardiopulmonary bypass, but also performs the function of routing cardioplegic solution through the heart in the retrograde direction. Such cardioplegia provides protection to the heart during periods of ischemic cardiac arrest. This invention replaces a plurality of cannulae currently used for open-heart surgery, thus simplifying the surgical field and improving visibility of the heart.
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This patent application is a division of application Ser. No. 12/109,191 filed Apr. 24, 2008, now U.S. Pat. No. 8,322,689 and this patent application claims the benefit of, and the priority to said application Ser. No. 12/109,191 filed Apr. 24, 2008.
FIELD OF THE INVENTION
The invention is in the field of conductor stringing apparatuses and processes.
BACKGROUND OF THE INVENTION
High voltage utility transmission lines are capable of supplying power over tens or hundreds of miles (or further) with minimal losses because of the very high voltages used. Step-up transformers located at utility power generation plants boost the voltage transmission levels up, depending on the particular utility, to and beyond 745 kV AC. At high voltages, power can be transmitted effectively as power transmission is a function of voltage times the current times the cosine of the phase angle between the voltage and the current. Use of high voltage minimizes current in the lines which thus minimizes losses which can be generally expressed as current squared times the resistance of the transmission line (i.e., the conductor).
Electrical demand in the United States and worldwide has steadily grown. Larger and more conductors are needed. Utilities constantly upgrade their systems at choke points in the grid to add new conductors and/or to replace existing conductors with new conductors which may be able to carry more current. Conductor stringing apparatuses and processes are used between utility towers or poles which may be separated by large distances, for example, they may be a quarter of a mile to a half a mile apart.
In a conductor stringing operation, a device called a conductor or cable puller-tensioner is used. Two machines are necessary. One of the machines functions as a puller which supplies the energy to pull the conductor against the friction of fixtures on the poles, against the force of the cable by virtue of its mass and the earth's gravitational attraction (i.e., its weight) and against the resistance supplied by the other machine which functions as a tensioner. The tensioner is a necessary part of the equipment and process lest the cable/conductor would sag and get tangled up with foliage, trees or other structures located beneath the cable/conductor path.
Previously, a drum puller/tensioner was typically powered by an internal combustion engine driving a hydraulic pump. The resulting pressure and flow in the hydraulic system coupled with a mechanical gear reducer would rotate the drum at the specified torque and speed. Tensioning was hydraulically controlled. As the pulling rope began to rotate the drum, it created pressure in the hydraulic system that could be adjusted to create the desired line tension.
U.S. Pat. No. 3,326,528 to S. S. McIntyre entitled Cable Stringing and Tensioning System discloses at col. 3, lns. 34 et seq. “the operator of the vehicle initially energizes the stator coils with current that may be supplied from a storage battery 50. Eddy currents are then generated by the relative motion of rotors and stator that produce a magnetic field in the rotors. This tends to retard rotation of the rotors and shaft 40, and this retarding force on shaft 40 builds up through the train of gearing . . . and is transferred back therethrough the sheaves . . . to resist their turning for braking the outfeed of transmission cable thereover.”
Many high voltage utility transmission lines are located in or near cities. Some of these lines require periodic replacement and/or upgrade and considerable noise and pollution is generated by internal combustion engines which power existing conductor stringing puller-tensioners. The noise and pollution present nuisances for those living in proximity to the high voltage transmission lines. It is, therefore, desirable to have a conductor stringing apparatus which is environmentally compatible and efficient.
SUMMARY OF THE INVENTION
An electric drive system powered by an on-board battery bank to run a drum puller-tensioner used in the utility industry is disclosed and claimed. Further, a multi-drum puller-tensioner or bullwheel tensioner may be used employing the principles expressed herein. The battery bank (renewable energy storage) is to be of sufficient voltage and capacity to allow operation for a minimum of two hours at maximum rated torque and speed. Tensioning is achieved by magnetic coupling of the rotor and stator of the electric motor. Although it is preferred to use an alternating current motor it will be understood by those skilled in the art that a direct current motor may be used. Energy produced during tensioning is stored in the battery bank or converted to heat by a resistor bank and can be maintained indefinitely at the maximum rated tension and line speed. It was determined that an electrical solution could be applied to replace the internal combustion engine and hydraulics that are traditionally used in hydraulic puller-tensioner. The benefits of the instant invention include zero emissions and extreme reduction in noise.
There are three electrical circuits used in the puller-tensioner. First, the main high voltage circuit operates nominally at 180 volts dc and supplies the electric motor after being converted by the motor controller to three phase alternating current power. Twelve (12) and twenty-four (24) volt dc circuits are used for accessory components.
The high voltage power source is comprised of thirty 30 deep cycle 12 volt batteries that are rated at 150 amp-hours each. “Amp-hours” is a measure of electric charge. One Amp-second is equal to one coulomb. One Amp-hour is equivalent to 3600 coulombs of electric charge. Fifteen (15), 12 volt dc batteries are wired in series to form the nominal 180 volt dc circuit. Two of the fifteen, 12 volt battery strings are wired in parallel resulting in a 180 volt power supply with a 300 amp-hour capacity. Trojan T-1275, 12 volt dc, lead acid deep cycle batteries with a 150 amp-hour capacity are the preferred batteries.
When fifteen (15) Trojan T-1275 batteries are wired in series they combine for a total of 180 VDC. When two strings of 15 batteries are connected in parallel they double the capacity to 300 amp hours. At this voltage, the maximum amp draw will be about 115 amps to supply a 20.7 kW load. The maximum current draw will be reached close to the end of a conductor stringing operation.
The batteries store enough energy to operate the unit for two hours and the combined voltage of the batteries is in the range required by the motor/controller. Any energy storage device that does this would be suitable. In other words, it is specifically contemplated that other battery types such as Lithium Ion and/or Nickel Metal Hydride may be used. Energy storage devices such as capacitors may also be used. Price being a factor, deep cycle lead acid batteries are used. Lead acid batteries give the most energy storage per dollar.
The electric motor is a 3-phase AC motor and rated for 34 kW. When pulling, the motor controller converts the 180 volt direct current energy from the batteries into alternating current to drive the motor. When tensioning, the motor controller converts the alternating current energy produced by the motor to direct current energy that is either stored in the batteries or converted to heat by the resistor bank.
The resistor bank is rated for 20 kW and is controlled by pulse width modulation. In the tension mode, electric energy is produced by the motor from higher tension and speed, more energy is allowed to be dissipated by the resistors. This is automatically controlled in the CAN-Bus program by monitoring battery voltage and adjusting the pulse width modulation accordingly which controls relay contacts, a solid state relay containing no moving parts, or and insulated gate bipolar relay containing no moving parts.
Converters are used to create constant twelve (12) and twenty-four (24) volt dc supplies from the high voltage circuit (180 volt dc) for supplying energy at the appropriate voltages to the accessories. The 180 volt system is charged using a custom, on-board, high voltage charger that is specifically designed for the batteries that are being used. There are a couple of companies that manufacture chargers specifically for the Electric Vehicle industry that would be appropriate. Based on price and ease of use, the Zivan NG-5 was chosen. It requires a 30 amp-230 VAC source and can charge a fully discharged battery pack in 10 hours. This charger was preprogrammed by the manufacturer for the specific battery used to ensure the proper charge curve for longer battery life. Other chargers may be adapted for use.
Alternatively, fresh batteries may be brought to the machine on a trailer if longer usage times are desired. If the customer believes they need that option, a small additional trailer with a set of batteries pre-wired may be supplied. Then it is a matter of unplugging the one plug that connects the onboard batteries to the circuit and plugging in the auxiliary batteries.
There are several secondary devices that are needed for full functionality. A custom electric brake is used in conjunction with the electric drive. The electric brake is able to supply a braking torque of 150 ft-lbs or, expressed another way, 1800 in-lbs. When the speed reduction of 67.642 of the sprockets and gearbox are considered the electric brake provides approximately 121,755 inch-lbs of resistive torque. The torque is sufficient to hold the pulling reel at maximum line pull when the machine is manually or automatically shut down. The level wind is powered by a Duff-Norton electro-mechanical cylinder.
Controlling the unit is a Parker IQAN-MD3 Master Module (hereinafter sometimes referred to as the “processor”). A CAN program was written using the IQAN Design which integrated all the components with the Parker IQAN MD-3. This allows communication with the Azure Dynamics, Inc. DMOC motor controller so that speed and torque can be controlled by user inputs. Safety features are included in the program and are designed to warn the user when unsafe parameters exist and safely shut down the machine when necessary.
The processor, its modules and the monitors require twelve (12) and twenty-four (24) volt dc sources. To obtain these voltages required by the controllers and monitors, a dc-dc voltage converter is used to convert the 180 volt dc circuit into lower voltages. A dc-dc converter was chosen from Metric Mind Engineering that produces 45 amps at 12 volts. The dc-dc converter keeps a single 12 volt battery charged that is dedicated to the 12 volt circuit and is used to power all secondary control devices and monitors.
A conductor stringing apparatus includes a frame and a conductor reel about which the conductor is wound. An electric motor is affixed to the frame and coupled to the conductor reel. The electric motor expends electrical energy when pulling the conductor in the pulling mode and the electric motor generates electrical energy when tensioning the conductor in the tension mode. The conductor stringing apparatus includes a processor and a motor controller in combination with the electric motor. The processor is switchable between a pulling mode and a tensioning mode. The processor outputs commands to the motor controller for control of the electric motor. A plurality of batteries is used to apply power to the electric motor and to receive power from the electric motor. The processor applies electrical energy from the batteries to the electric motor when in the pulling mode. The processor applies electrical energy generated by the electric motor to the plurality of batteries when in the tensioning mode. The processor limits electric motor torque and speed based on operator commands for speed and torque in the pulling mode. The processor controls electric motor torque in the tensioning mode.
The three phase electric motor consumes electrical energy in the pulling mode. The Azure Dynamics Inc. motor controller converts direct current into alternating current according to a command message from the Parker IQAN MD-3 controller and applies it to the three phase alternating current electric motor. Other three phase electric motors may be used with separate stand-alone motor controllers. Further, direct current motors may be used with appropriate controls.
The conductor stringing apparatus includes a resistor bank. The processor applies electrical energy to the batteries and to the resistor bank. The processor periodically applies electrical energy to the resistor bank using a pulse width modulation control signal to a control relay. Alternatively, a solid state relay or an insulated gate bipolar transistor may be used. Pulse width modulation is employed wherein the processor controls the application of control signals to the gate of an insulated gate bipolar transistor. The electric motor is an alternating current motor and the motor controller converts direct current battery power to alternating current power. The motor controller converts alternating current power into direct current power for application to the battery or to the resistor bank. A charger for charging the batteries from an external AC power supply is used to charge the batteries at night or when the apparatus is not in use.
A battery temperature sensor generates a signal representative of the battery temperature and inputs the battery temperature signal into the processor. The processor, using the battery temperature sensor, decides whether to continue operation of the conductor stringing apparatus. If the temperature of the battery is greater than 120° F. then operation for the machine is discontinued. The battery temperature sensor may be a thermocouple in engagement with the first negative battery post of fifteen batteries connected in series.
A process for stringing a conductor is also disclosed and includes the initial step of switching between pulling and tensioning modes as desired. Further steps include controlling an electric motor using a processor and a motor controller. In the preferred embodiment the motor controller-motor combination are supplied by Azure Dynamics, Inc. Electrical energy from a plurality of batteries is consumed in the electric motor when pulling a conductor in pulling mode. The electric motor generates electrical energy and charges the plurality of batteries under certain conditions when tensioning a conductor in tensioning mode. Battery voltage is continuously monitored and when it reaches 198 volts dc, the processor begins applying current to the resistor bank to dissipate the energy in the form of heat. The processor limits the electric motor torque and speed based on operator commands for speed and torque in the pulling mode. The processor controls the electric motor torque in the tensioning mode and thus provides tension to the system. The process for stringing a conductor further comprises the steps of dissipating excess electrical energy in a resistor bank when the voltage measured across the string of 15 batteries in series is equal or greater than 198 volts dc.
Accordingly, the process for stringing a conductor includes the steps of measuring battery voltage, processing the battery voltage, and, controlling the dissipation of excess electrical energy in the resistor bank depending on the battery voltage. The step of controlling the dissipation of excess electrical energy in the resistor bank includes modulating the pulse width of a control signal to a switching device in series with the resistor bank. Preferably, the switching device is a control relay, an insulated gate bipolar transistor, or a solid state switching device. Application of the pulse width begins at 198 volts dc and continues and increases linearly up to and including 215 volts dc.
The process for stringing a conductor includes the steps of: monitoring battery temperature; and, discontinuing the stringing operation when the battery temperature exceeds a temperature limit of 120° Fahrenheit. The battery temperature is sensed from a thermocouple engaged with the first negative battery post of the string of 15 batteries.
It is an object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which is capable of energy recovery in the tensioning mode.
It is an object of the invention to provide an electric conductor stringing puller-tensioner which is of the multi-drum type for the electric utility industry which is capable of energy recovery in the tensioning mode.
It is an object of the invention to provide an electric bullwheel tensioner for the electric utility industry which is capable of energy recovery in the tensioning mode.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner with an energy management system for handling energy recovered in the tension mode.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which employs pulse width modulation control in dividing energy between storage batteries and a resistor bank for dissipating energy as heat.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which controls the speed of the reel between upper and lower torque values.
It is a further object of the invention to provide an electric bullwheel tensioner having positive control of the conductor or wire released under tension.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which employs an insulated gate bipolar transistor to implement pulse width modulation control of the resistor bank.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which employs a solid state switch device to implement pulse width modulation control of the resistor bank.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which employs a control relay to implement pulse width modulation control of the resistor bank.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner apparatus which employs an alternating current motor controlled by a motor controller which converts direct current to alternating current.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner for the electric utility industry which is environmentally compatible and efficient.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner apparatus for the electric utility industry which is capable of energy recovery in the tension mode.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner apparatus for the electric utility industry which is capable of energy recovery in the tension mode and which is controllable based on battery bus voltage.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner apparatus for the electric utility industry which is capable of battery management and protection based on the temperature of the batteries.
It is a further object of the invention to provide an electric conductor stringing puller-tensioner apparatus for the electric utility industry which employs a thermocouple attached to the negative post of the battery connected to the negative battery bus.
Further objects of the invention will be understood when reference is made to the drawings, description of the invention and claims which follow hereinbelow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prior art illustration of a conductor stringing tensioner and puller.
FIG. 2 is a side view of the conductor stringing puller-tensioner of the instant invention.
FIG. 2A is a view taken along the cross-sectional lines 2 A- 2 A of FIG. 2 .
FIG. 2B is a top view of the conductor stringing puller-tensioner of the instant invention.
FIG. 2C is a cross-sectional view of the conductor stringing puller-tension of the instant invention taken along the lines 2 C- 2 C of FIG. 2B .
FIG. 2D is a rear view of the conductor stringing puller-tensioner of the instant invention.
FIG. 2E is a sectional drawing taken along the lines of 2 E- 2 E of FIG. 2B illustrating the battery securement.
FIG. 2F is a sectional drawing taken along the lines of 2 F- 2 F of FIG. 2B illustrating the battery securement.
FIG. 2G is a perspective view of a battery and terminals.
FIG. 2H is an enlargement of a portion of FIG. 2G illustrating a screw in the negative most terminal.
FIG. 3 is a schematic ladder diagram of the 180 volt dc circuit which includes the batteries, the resistor bank, the three phase electric motor and motor controller.
FIG. 3A is a schematic ladder diagram of the 12 volt dc circuit which includes the modules of the processor, various relays, and the Insulated Gate Bipolar Transistor.
FIG. 3B is a schematic illustrating: a processor module, rocker switches, joystick, the voltage transducer monitoring the 180 volt dc circuit and the temperature transducer monitoring the battery temperature.
FIG. 3C illustrates operation of the resistor bank and the pulse width modulation control signal.
FIG. 3D is a schematic ladder diagram of the 180 volt dc circuit which includes the batteries, the resistor bank, the three phase electric motor, motor controller and an ultra-capacitor in parallel.
FIG. 4 is an illustration of the control panel.
FIG. 5 is a schematic diagram of the master start sequence of the conductor stringing puller-tensioner.
FIG. 5A is a schematic diagram of the motor control for the puller mode and the tension mode of the conductor stringing puller-tensioner.
FIG. 5B is a schematic diagram of the energy control in the tension mode.
A better understanding of the drawings will be had when reference is made to the description of the invention and the claims which follow hereinbelow.
DESCRIPTION OF THE INVENTION
FIG. 1 is an illustration 100 of a conductor stringing tensioner 105 and puller 104 . Poles 101 and insulators 102 are illustrated as is a conductor pulling rope and conductor. Insulators 102 and stringer attachment 103 are illustrated in FIG. 1 as is the traveling ground.
FIG. 2 is a side view 200 of the conductor stringing puller-tensioner of the instant invention illustrating the resistor bank cabinet 201 , control panel 211 , and control box housings 211 A, 211 B. An operator of the device is protected by a protective screen 213 in the event of a rope or conductor break under tension. Joystick 311 A can be seen in FIG. 2 protruding from the control panel. Batteries are secured in an undercarriage formed of channel 210 which is obscured from view in FIG. 2 by battery skirt 202 . Chain guard 203 protects a person from entanglement with a chain (not shown) which operates between a small sprocket (not shown) having 19 teeth per revolution and a large sprocket (not shown) having 84 teeth per revolution. Reel 205 upon which conductor or rope is wound and reel shaft 204 are viewed well in FIG. 2 . An outer frame 206 supports the operator and his or her chair as well as the control panel. The main frame 207 supports the batteries, the electric motor, the chain and the conductor/rope reel. Wheel covering/wheel guard 203 is illustrated over wheels/tires. The outer and main frames 206 are covered with metal plates enabling limited mobility of the operator around the machine.
FIG. 2A is a view 200 A taken along the cross-sectional lines 2 A- 2 A of FIG. 2 . Batteries 220 are illustrated residing in channels 210 . Channels 210 include upwardly extending portions 220 A. Motor controller 240 A is illustrated in FIGS. 2A and 2C . FIG. 2B is a top view 200 B of the conductor 230 stringing puller-tensioner of the instant invention. Flooring-battery covering 231 , 231 A, 231 B and 231 C are metal plates which are attached to the frame 206 , 207 with screws or other attachment means as shown in FIG. 2B . Battery hatch 211 B allows access to battery 319 which supplies start-up control power to the 12 volt dc circuit illustrated in FIG. 3A . The flooring-battery coverings reside over the batteries and enable limited movement by the operator or maintenance personnel on the device. The batteries 220 are held in place by tie-downs 220 B as illustrated in FIG. 2B .
The batteries may be replaced periodically for maintenance, repair or substitution of a fresh fully charged battery. Alternatively, an auxiliary trailer having thirty (30) fully charged 12 volt dc batteries may be placed in proximity to the conductor puller-tensioner as a supplemental energy source for longer pulls. The auxiliary batteries may be coupled by using a socket and plug interconnection 320 . Reference numeral 320 diagrammatically illustrates the socket and plug and includes necessary electrical interconnection and extensions to the supplemental energy source.
FIG. 3 is a schematic ladder diagram 300 of the nominal 180 volt dc circuit which includes batteries 220 , resistor bank 316 , alternating current motor 240 , and DMOC motor controller 240 A. As for the resistor bank, it is a customized grouping of 15 individual resistors from Milwaukee Resistor's Edge Power product line. Five (5) 2.75 ohms resistors are in parallel with each other and form a set. Each individual resistor has a resistance of 2.75 ohms. Each set of resistors has a resistance of 0.55 ohms and then three sets of the resistors are series with each other for a total resistance of 1.65 ohms.
In FIG. 3 , the batteries 220 are illustrated as being connected in series. The power required by the three phase alternating current motor 240 is approximately 27.767 Hp (20.7 Kw) and the required torque is approximately 70,000 in-lbs. The reel sprocket (not shown) includes 84 teeth per revolution and the motor sprocket (not shown) includes 19 teeth per revolution. The sprockets reside within the chain guard 203 and are not visible. The reduction of the gearbox is 15.3:1 and the total reduction is 67.642 which yields a torque requirement of 1,034. 8 in-lbs (116.9 N-m). The required reel speed is 25 rpm which yields a required motor speed of 1691 rpm. Different speeds, torques and gear reductions may be used as will be recognized by those skilled in the art without departing from the spirit and scope of the invention as set forth herein.
Still referring to FIG. 2B , conductor 230 is illustrated wound on reel 205 . Level winds 310 B, 310 C are illustrated in FIG. 3A which are responsible for winding and unwinding the rope or conductor onto and off-of reel 205 in an orderly fashion for efficient storage and payout. Adapter 241 , multi-disc brake 242 and gearbox (gear reducer) 243 are illustrated in FIG. 2B .
FIG. 2C is a cross-sectional view 200 C of the conductor stringing puller-tensioner of the instant invention taken along the lines 2 C- 2 C of FIG. 2B with the reel and the three phase alternating current motor removed. FIG. 2C illustrates the batteries 220 and their placement in the channel 210 and the upwardly extending portion 220 A of the channel FIG. 2D is a rear view 200 D of the conductor stringing puller-tensioner of the instant invention.
FIG. 2E is a sectional view 200 E taken along the lines of 2 E- 2 E of FIG. 2B illustrating the battery securement. Tie down rod 252 which may be partially threaded rod or it may be threaded along its entirely length. Rod 252 is connected to the lower plate 254 which traverse channels 210 . Nut 256 threads onto the tie down rod 252 and applies pressure to upper plate 220 B against the batteries 220 . Reference numeral 258 is the side wall of the battery enclosure. FIG. 2F is a sectional view 200 F taken along the lines of 2 F- 2 F of FIG. 2B illustrating the battery securement.
FIG. 2G is a perspective view 200 G of a battery 220 and terminals 261 , 262 . FIG. 2H is an enlargement 200 H of a portion of FIG. 2G illustrating a threaded screw 265 in the negative most terminal 262 . Reference numeral 263 indicates the female threads within post/terminal 262 . Thermocouple 264 may be affixed into engagement with the terminal 262 to monitor the temperature of the battery.
Referring to FIG. 3 , a schematic ladder diagram 300 of the nominal 180 volt dc power system is illustrated. The voltage is referred to as nominal, meaning ordinary or expected. However the voltage across the battery strings arranged in parallel with each other varies. Specifically, in the tensioning mode, if the voltage exceeds 198 volts dc, then the 20 kW resistor bank 316 dissipates some of the energy according to the width of a pulse width modulation control signal applied to a relay, solid state switching device, or an insulated gate bipolar transistor 349 . Insulated gate bipolar transistors function as a switch applying current to the resistor bank. Alternatively, contacts of CR 5 may be used to control the application of the regenerated energy from the alternating current motor 240 /DMOC controller/processor 240 A to the resistor bank.
Alternatively, an ultra-capacitor 391 may be used in parallel with the string of batteries as illustrated on FIG. 3D . FIG. 3D and FIG. 3 illustrate the same components only FIG. 3D includes the ultra-capacitor capable of storing a large amount of charge. Ultra-capacitors or electrochemical double layer capacitors (EDLC), are electrochemical capacitors that have an unusually high energy density when compared to common capacitors, typically on the order of thousands of times greater than a high-capacity electrolytic capacitor. Ultra-capacitors store several are capable of storing many farads and some large commercial ultra-capacitors have capacities of thousands of farads.
The three phase alternating current motor 240 (Azure Dynamics Inc. Model no. AC55) and the DMOC motor controller 240 A are supplied by Azure Dynamics Inc. of Woburn, Mass. as a motor/controller package. The three phase alternating current motor is rated for 34 kW continuous power, 240 N-m peak torque, and 8,000 rpm maximum speed. Other electric motor-motor controller packages may be used as those skilled in the art will readily recognize for different loads and machine characteristics.
Referring to FIG. 3 , the high voltage power source is comprised of thirty (30) deep cycle twelve (12) volt batteries 220 that are rated at 150 amp-hours each. Fifteen (15), twelve (12) volt dc batteries 220 are wired in series to form the nominal 180 volt dc circuit. Two of the fifteen (15), twelve (12) volt battery strings are wired in parallel resulting in a 180 volt pack with a 300 amp-hour capacity. Trojan T-1275 Plus, 12 volt dc, lead acid deep cycle batteries with 150 amp-hour capacity are the preferred batteries 220 . The batteries may be charged in the tension mode as explained herein or they may be charged overnight or when the puller-tensioner is not in operation by employing charger 305 . Charger 305 is a Nivan Charger having an input source voltage of 230 volts AC and can draw 30 Amps. Charger 305 outputs 180 volts DC. At a voltage of 180 volts dc, the maximum current draw will be about 115 amps to supply a motor load of 20.7 kW. The maximum current draw will only be reached close to the end of a conductor stringing operation.
Voltage across the battery strings is monitored 370 , 371 by a voltage transducer illustrated in FIG. 3B . FIG. 3B is a schematic 300 B illustrating: a processor module 306 , rocker switches 311 , joystick 311 A, voltage transducer 307 monitoring the 180 volt dc power system and the temperature transducer 307 A monitoring the battery temperature. Processor 306 , 306 A, 306 B, and the DMOC motor controller 240 A use CAN program parameters for communication and processing. The voltage transducer 307 monitors the voltage 370 , 371 on terminals 323 , 323 A and outputs (from terminal 326 ) a signal 338 A which is input into and communicates with terminal 338 of processor 306 . Processors 306 , 306 A, and 306 B are an IQAN Parker Hannifin MD-3 processor. Processor 306 includes terminal 339 which communicates with terminal 339 A of module 306 A. Expansion module 306 B includes terminals 359 , 360 which communicate with terminals 357 , 358 of module 306 A.
Voltage monitoring across the battery strings is important as the voltage may increase during tensioning mode and the batteries are limited as to how much energy or charge them may accept per unit time and contain. The voltage transducer requires a 24 volt dc supply which is supplied at pins 324 , 312 of the transducer. Voltage converter 321 is powered from the 12 volt dc logic circuit illustrated in FIG. 3A and steps up the voltage to 24 volts dc for application to the voltage transducer 307 and the temperature transducer 307 A.
At a voltage of 198 volts dc as monitored across the nominal 180 volt dc power supply circuit, the processor begins to modulate the amount of energy applied to the batteries and directs the energy to the resistor bank 316 . At 198 volts DC the processor enables relay CR 4 (SWITCH 349 ) which is output from terminal 346 of processor module 306 B. Engineering units of volts dc across the battery string are converted by a CAN program into counts for use within the CAN program. Energization of relay CR 4 closes contact CR 4 which then allows current to flow in the circuit and then applies power to energize relay CR 5 . Upon energization of relay CR 5 , contacts CR 5 in series with resistor bank 316 enables application of current for the dissipation of energy in the resistor bank 316 .
FIG. 3C illustrates 300 C operation of the resistor bank pulse width modulation control signal. Specifically, reference numeral 349 E illustrates the battery voltage. Reference numeral 349 D indicates the resistor power dissipation in Watts. Reference numeral 349 C illustrates the pulse width that corresponds to a particular voltage in the range of 198 volts to 215 volts dc. Reference numeral 198 illustrates that when the voltage across the battery strings reaches 198 volts dc, a resistor pulse width modulation signal is applied to CR 4 (or other switching device) which controls relay contacts CR 5 in series with the resistor ban. The pulse width modulation signal begins at 198 volts dc and increases linearly such that when 215 volts dc is reached the application of current to the resistor bank is constant, specifically, current is applied 100% of the time and 20 kW is dissipated in the resistor bank. The resistor bank dissipates 20 kW and is comprised of sets of resistors which have a total resistance of 1.65 ohms. Specifically there are three sets of resistors in series with each set having five 2.75 ohm resistors arranged in parallel.
The invention includes a battery charging algorithm. Checks and balances are used during tensioning for a safe battery pack charge. Voltage, current, and temperature are all used in the program to control it. Generally, charging current of a battery system is equal to Current/10, where Current is the 20 hr capacity of the system. Each battery string employs batteries having a 150 Amp-hour capacity. System capacity is 300 Amp-hours because two battery strings are used so charging current is nominally 30 amps.
Current is not measured directly and externally to the DMOC motor controller 240 A. Current is calculated from the power generated from tensioning. We have inputs for speed and torque from the DMOC motor controller 240 A, so horsepower is calculated from the formula Horsepower=(ft-lbs*rpm)/5252. Horsepower is then converted Watts as 746 Watts is approximately equal to 1 horsepower. Current in Amps is equal to Watts/Volts. The program uses torque, speed, voltage, current and temperature for use in operating the resistor bank and charging the batteries.
The program uses these values to decide if, and how much to pulse the resistors. If the charge rate is below 30 amps, and if the voltage is below 198 VDC, and if the temperature is below 118 degrees F., then the resistors are not used, or pulsed at zero percent.
There are three calculations made to determine the pulse rate of the resistors. They are all a percentage of the total resistive power. The program picks the largest value to use as the actual PWM percentage employed.
Formula 1: Current based pulse width modulation percentage.
A charge current of 30 amps is the nominal charging current. Potential resistive power of the resistor bank is determined by squaring the voltage and dividing by the resistance. Resistance of the resistor bank is a constant 1.65 ohms as explained elsewhere herein. Voltage of the 180 volt circuit is not constant and is changing depending on operational conditions and, as such, the potential power is also changing. Power is calculated from the tensioning. Power in the batteries is 30 amps multiplied by the instantaneous voltage and may range from 5.4 kW to 6 kW, more or less. Power supplied to the batteries is subtracted power from the power determined and generated by the tension and what remains, for example, the difference is the power dissipated in the resistor bank. Power to be dissipated in the resistor bank is divided by the potential resistive power and is multiplied by 100 to get a pulse width modulation percentage. This is the PWM percentage determined using a current analysis.
Formula 2: Voltage based pulse width modulation percentage.
The calculation for voltage is much simpler than the calculation for current. The battery voltage should not exceed 217 volt dc but needs to be above 190.5 volts dc to charge the batteries. A linear calculation between 198 and 215 volts dc is used to determine a linear pulse width modulation percentage. In other words, the pulse width varies between 0 and 100 percent as the voltage varies between 198 and 215 volts dc. Consequently, this is the formula that is used most often by the program because even if the charge rate is below 30 amps the voltage increases.
Formula 3: Temperature based pulse width modulation percentage.
The temperature of the batteries does not exceed 120 degrees F. When the temperature reaches 118 degrees F., we equal the tension power and resistive power so that there is no charge or discharge in the batteries and the resistors handle all of the current.
Again, these three formulas all calculate a percentage. The greatest percentage is the one that the program uses.
Battery temperature is monitored by the battery transducer 307 A. Engineering units of degrees Fahrenheit are converted into counts for use in the CAN program. The temperature transducer circuit is supplied by the voltage converter 321 with 24 volts dc across terminals 313 , 329 . A thermocouple input 315 A is applied across terminals 314 and 315 of the temperature transducer. The temperature transducer 307 A outputs a signal 318 A on pin 318 which communicates with pin 330 on processor 306 . If battery temperature exceeds 120° F. then the machine is shut down and relay contacts CR 2 and CR 3 in the 180 volt circuit open. Relay contacts CR 2 and CR 3 open as the output of pin 348 goes to zero and disables relay CR 6 . With relay CR 6 de-energized, contacts CR 6 , CR 6 open de-energizing relay contacts CR 2 , CR 3 which result in the isolation of the battery strings 220 from electric motor 240 /motor controller 240 A and from the dc-dc converter 317 .
The 12 volt dc control circuit is supplied by the output 374 , 375 of the 180 vdc-12 vdc converter 317 illustrated in FIG. 3 . Converter outputs 374 , 375 are also viewed in the upper portion of FIG. 3A . Referring to FIG. 3A , voltage isolating converter 309 supplies 12 volts dc from unnumbered terminals and communication points 382 , 383 to battery meter 301 ( FIG. 3 ) as indicated by communication points 382 , 383 which in turn communicate with pins 361 , 365 of the battery meter. The battery meter includes a shunt 351 which provides an input to pins 362 , 363 of the battery meter. Prescaler 301 A is also used in connection with the battery meter and communicates with terminals 361 and 364 respectively.
Referring to FIG. 3 , alternating current three phase motor 240 and DMOC controller 240 A are illustrated. Reference numerals A, B, C indicate the three phase inputs to the windings of the motor. Twelve (12) volts dc are applied across terminals 369 , 350 of the DMOC through communication with the 12 volt dc supply 374 , 375 from the 180 volt dc-12 volt dc converter 317 . A CAN control message is applied to pins 366 , 367 of the DMOC motor controller 240 A. The CAN control message comes from processor 306 pins 355 , 356 of the IQAN MD-3 processor 306 and is interconnected 378 , 379 to the DMOC controller 240 A. Similarly status messages are communicated from the DMOC motor controller 240 A back to the processor 306 . The DMOC controller 240 A applies an algorithm which depends on the operational mode of the processor, for instance, whether the processor is in the tension mode or pulling mode. Further, processor 306 and its modules 306 A, 306 B are in communication with an interface 406 illustrated in FIG. 4 . Voltage, temperature, speed, torque as well as other parameters are displayed on the graphical interface 406 .
In the pulling mode, lower torque and upper torque are set by the operator. Speed is also operator controlled in a range of plus and minus 0 to 100% with a dead band of +/−10%, but is limited by the values input for lower and upper torque. The speed regulator is active within the window given by the lower and upper torque limit. The speed set-point as well as the toque limits are transmitted over CAN and may be modified by the DMOC at a rate of 20 hz. If the speed set value can be reached within the torque limits then speed regulation as commanded by the operator speed input is achieved. If the limits are too restrictive, for example, the lower torque and the upper torque are too close together, then the drive becomes essentially torque controlled.
In the tension mode, lower torque is set equal to upper torque and the tensioner acts as a classical torque resistance or tensioner.
Referring to FIG. 3B , rocker switch 311 communicates with pins 331 , 332 of processor 306 . Joystick 311 A includes right (increase) and left (decrease) torque pushbuttons. Depressing the right button 407 B communicates a torque increase signal to pin 332 of processor 306 . See FIG. 4 for an illustration of the torque push button 407 A, 407 B. Depressing the left button 407 A communicates a torque decrease signal to pin 331 of processor 306 . Source voltage is applied to pin 335 and ground is applied to pin 334 . The speed signal input, directionally indicated as plus-minus 100% is applied to pin 333 of the processor 306 . Speed input is controlled by the Joystick single axis forward and reverse movement as indicated in FIG. 4 . A USB port communicates with pins 336 , 337 . The torque inputs to processor 306 are digital inputs and the joystick speed on pin 333 , the battery bus voltage on pin 338 and the battery temperature on pin 330 are analog inputs. Torque and speed inputs are user controlled while operating the puller-tensioner.
FIG. 3A is a schematic ladder diagram 300 A of the 12 volt dc circuit which includes the modules of the processor 306 A, 306 B, relays CR 1 , CR 4 , CR 5 , CR 2 , CR 3 , level wind actuator motors 310 , 310 A and switch 349 . Battery 319 supplies energy for the control logic set forth in FIG. 3A before the puller-tensioner is started. A DC-DC converter 317 keeps the 12 volt dc battery 319 charged via interconnection points 374 , 375 of the converter 317 and interconnection points 380 , 381 of the 180 volt dc circuit. Key switch 302 energizes relay CR 1 which is a permissive to application of power to the isolating DC-DC converter for the battery meter 301 , the level wind actuators 310 , 310 A and the processor 306 , 306 A, 306 B. Switch 302 is also viewed on FIG. 4 and is labeled system enable.
Processor module 306 A is powered by the 12 volt dc bus at terminals 352 , 354 as illustrated in FIG. 3A and socket relay indicates that the processor is active. Similarly processor module 306 B is supplied with power at pins 340 , 345 . RS 232 communication is accomplished at terminals 343 , 344 of module 306 B. An address tag is communicated at terminals 341 , 342 of module 306 B. Processor 306 B drives the brake disable relay which controls the electric brake 242 contained within the electric motor-electric motor brake housing. Electric brake 242 is applied when the electric motor 240 is commanded to shutdown when the battery temperature exceeds 120° F.
Still referring to FIG. 3A , control relays CR 2 and CR 3 are enabled when relay CR 6 is energized closing contacts CR 6 , CR 6 . Control relay CR 6 is energized when the joystick 311 A is centered or it is within its dead band zone (plus-minus 10% of being centered) and the holding electric brake 242 is off. When CR 6 is energized two sets of contacts CR 6 are enabled which, in turn, enable CR 2 and CR 3 which then energizes the 180 volt dc circuit upon the closure of contacts CR 2 , CR 3 as illustrated in FIG. 3 .
FIG. 4 is an illustration 400 of the control panel 408 . Control panel 408 is viewed by the operator and informs the operator as to several important parameters. First, key 302 enables the system. Battery meter 301 indicates the voltage across the battery strings. Brake pressure 404 is the pressure applied by the brake within the motor-brake assembly. The electric brake can be manually applied by the operator through toggle brake arm 405 . The direction 403 of the level wind is controllable as is viewed in FIG. 4 . Joystick 311 A and torque increase 407 B and torque decrease 407 A buttons are illustrated. Indicia 420 instructing the operator as to operation of the joystick (payout and pull-in) and the torque inputs is applied to the control panel 408 .
Master control interface 406 is illustrated in FIG. 4 having a display screen for conveying information to the operator. F 1 , designated by reference numeral 430 , is depressed to enter the puller mode. F 2 , designated by reference numeral 431 , is depressed to enter the tensioning mode. Button F 3 , designated by reference numeral 432 , is depressed to enter the diagnostic mode.
In the pulling mode, input and actual speed and torque are displayed. Battery temperature and voltage are also displayed. The operator may also reset the torque by depressing one of the arrow buttons on the controller (processor) interface 406 . The controller temperature is also indicated.
In the tension mode, input and actual speed and torque are displayed. Battery temperature and voltage are also displayed. Also, in the tension mode the percentage of the pulse width modulation being applied is also displayed. A green light is displayed on the processor screen indicating that the controller is operating in the tension mode. The controller temperature is also indicated.
In the diagnostic mode the input and output speed and torque are displayed in parametric indications of the CAN program.
FIG. 5 is a schematic diagram 500 of the master start sequence of the conductor stringing puller-tensioner. Reference numeral 501 indicates the master start sequence. The first query 502 is whether the joystick lever is centered. If the joystick lever is not centered, the operator must center it to enable the 180 volt dc circuit. So, in other words, the joystick must be centered plus or minus 10% as previously indicated as a permissive to starting the puller-tensioner. Next, the holding brake must be off and a query 503 in this regard is represented in the flow chart. If the brake is off then the 180 volt dc circuit can be enabled by energizing control relays CR 6 , CR 2 , and CR 3 . If the holding brake is not off, it must be positioned in the off position. To enable the 180 volt dc circuit, relays CR 6 , CR 2 and CR 3 are energized. Therefore, the CAN program requires the joystick to be centered +/−10% and the motor brake 242 must be off.
FIG. 5A is a schematic diagram 500 A of the motor control 505 for the puller mode and the tension mode of the conductor stringing puller-tensioner. If the machine was automatically shutdown 506 then the input speed is automatically set to zero 507 . If the machine was not automatically shut down then the input speed and direction is determined 508 by the operator positioning the joystick lever. Upper and lower torque is then determined and set by the operator by pressing right 407 B or left 407 A joystick buttons 509 .
If the machine is in the puller mode 510 then a query 511 is present as to whether or not the torque reset button has been pressed. If the torque reset button has not been pressed then the lower torque is set to zero 515 and the upper torque remains as set in step 509 . If the torque reset button has been pressed then the reset is confirmed 512 , 513 through messages displayed on the interface 406 and the upper torque is set to zero 514 and the lower torque is also zero 515 . For this condition, where the pulling mode is active and the reset button is pressed the upper and lower torque are both set to zero. If the torque button has not been depressed then in the pulling mode the motor is operating with an upper torque set by the operator and a lower torque set at zero.
Still referring to FIG. 5A , in tension mode, the lower and upper torque are equal 516 and determined by the upper torque setting 509 .
Still referring to FIG. 5A , next, regardless of tension or pulling mode, the input speed, upper torque, and lower torque values are converted into CAN program parameters 517 and transmitted to the motor controller via the CAN bus 518 . The input speed and upper torque values are mathematically processed 519 for display 520 as input values on the interface 406 . The processor receives actual speed and torque values 521 from the DMOC motor controller 240 A and mathematically processes them 522 and displays them as actual values 522 , 523 .
FIG. 5B is a schematic diagram 500 B of the energy control and management system in the tension mode 524 resulting from depressing the tension function key 525 . In the tension mode the joystick lever must be pushed back to plus or minus 10% and the tension mode green lamp is displayed 527 . Battery temperature from the controller is received by the processor via the CAN bus 528 and is mathematically processed 529 for display in engineering units of volts dc 530 . The resistor bank pulse width modulation duty cycle is calculated 531 depending on the voltage. The resistor bank is enable by the pulse width duty cycle as dictated by CR 5 532 . The pulse width modulation duty cycle as a percentage is displayed 533 on the graphical interface. Battery temperature is measured 534 and mathematically processed 535 and displayed 536 in engineering units. If the battery temperature is greater than 120° F. then the holding brake is applied 538 and the machine is shut down 539 . If the temperature is less than 120° F. then the temperature is processed for display in engineering units 528 , 529 and the steps are repeated.
The input for speed is an analog signal originating from a bi-directional, single-axis joystick on the control panel. The signal that it sends is a voltage ranging from 500-4500 mV when the joystick is in its full back or full forward position, respectively. This voltage signal is received by the Parker IQAN MD3 control module/processor 306 and is represented by the voltage-in channel (pin 333 ) labeled Joystick. In this channel the voltage signal is converted to a percentage that ranges from −100 to 100. This value is converted into CAN program parameters. First, a dead zone is created by specifying that between −10% and +10% the value will be zero. Second, the range is converted to the CAN parameters needed by the Azure Dynamics, Inc. motor controller 240 A. This CAN parameter value is 670 for max speed.
The inputs for torque are the two buttons 407 A, 407 B on the top of the joystick 311 A. Each button inputs to channel (pins 331 , 332 ) on processor 306 . The right button 407 B is connected to pin 332 to raise torque and the left button is connected to pin 331 to lower torque. An event-counter counts the amount of times the user presses the joystick buttons, adding when the right button 407 B is pressed and subtracting when the left button 407 A is pressed. The user reaches maximum torque after 100 clicks of the right button. The value for maximum torque in CAN parametric form is 1146.88. To reach this value in 100 clicks, each count of the Joystick is multiplied by 11.4688. This value is sent to the parameter-out channel and is the upper torque limit. The parameter-out channel, lower torque limit is either zero, as is the case when pulling, or is equal to the upper torque limit, as is the case when tensioning.
Three parameter-out channels, speed control, upper torque limit, and lower torque limit, are attached to the generic frame out channel, control message. The control message is sent to the Azure Dynamics Inc. motor controller 240 A where it interprets the inputs and regulates the motor speed and torque accordingly. The motor controller 240 A communicates status messages back to the processor 306 for processing and display on display 406 .
The algorithms implemented by the processor described herein are set forth by way of example only. It is specifically contemplated that different algorithms may be used for the control of, for example, the electric motor(s), tension, speed, torque and safety and other parameters without departing from the spirit and scope of the claimed invention.
REFERENCE NUMERALS
A, B, C—motor phases
F 1 —puller function key
F 2 —tension function key
F 3 —diagnostic function key
CR 1 —actuator relay and relay contacts
CR 2 —180 Vdc relay and relay contacts
CR 3 —180 Vdc relay and relay contacts
CR 5 —resistor bank relay and relay contacts
100 —prior art schematic of conductor stringing process
101 —pole
102 —insulator
103 —stringer attachment
104 —puller
105 —tensioner
200 —side view of puller-tensioner
200 A—cross-sectional view taken along the lines 2 A- 2 A of FIG. 2
200 B—top view of puller-tensioner
200 C—cross-sectional view taken along the lines 2 C- 2 C of FIG. 2
200 D—rear view of the puller-tensioner
200 E—sectional view taken along the lines of 2 E- 2 E of FIG. 2B .
200 E—sectional view taken along the lines of 2 F- 2 F of FIG. 2B .
200 G—perspective view of battery and terminals
200 H—enlargement of a portion of FIG. 2G
201 —resistor bank cabinet
202 —battery skirt
203 —chain guard
204 —reel shaft
205 —reel
206 —frame (frontal portion)
207 —main frame
208 —wheel covering/wheel guard
210 —channel forming battery supports
211 —control panel
211 A—control box housing
211 B—battery hatch
212 —joystick
213 —protective screen
220 —battery
220 A—upwardly extending portion of channel
220 B—battery upper plate for tie down
230 —conductor
231 , 231 A, 231 B, 231 C—flooring/battery cover
240 —three phase electric motor
240 A—DMOC motor controller
241 —adapter
242 —multi-disc brake
243 —gearbox
252 —tie down rod which may be partially threaded
256 —nut which threads onto the tie down rod
254 —lower plate affixed to and traverses channels
258 —side wall of battery enclosure
261 , 262 —battery terminals 261 , 262 .
263 —female threads within terminal 262
264 —thermocouple 264 affixed into engagement with the terminal 262
300 —180 volt ladder diagram
300 A—12 volt ladder diagram
300 B—joystick, temperature and voltage transducer
300 C—pulse width modulation schematic
301 —battery meter
301 A—prescaler
302 —keyed switch
305 —charger
306 —processor, Parker Hannifin, IQAN MD3-C1
306 A—IQAN module
306 B—IQAN Expansion Module
307 —voltage transducer
307 A—temperature transducer
308 —180 volt battery
309 —isolating converter for battery monitor
310 , 310 A—level wind actuator motors
311 —torque rocker switch inputting to IQAN MD3-C2
311 A—joystick
312 —negative (−) 24 volts dc
313 —positive (+) 24 volt dc supply to voltage transducer
314 —thermocouple attached to first negative battery terminal
315 —thermocouple attached to second negative battery terminal
315 A—thermocouple
316 —resistor bank
317 —180 volt dc−12 volt dc+converter
318 —output terminal of temperature transducer
318 A—output (volts dc) to processor representing battery temperature
319 —12 volt battery
320 —battery interconnection with motor circuit, resistor bank and meter
321 —voltage converter 12/24 volt dc
323 —positive (+) 180 volt dc supply
323 A—negative (−) 180 volt dc supply
324 —positive (+) 24 volts dc
325 —socket relay
326 —output (volts dc) to processor representing voltage temperature
329 —negative (−) 24 volt dc supply to voltage transducer
330 —battery temperature input terminal
331 —lower torque pushbutton terminal
332 —raise torque pushbutton terminal
333 —ground
334 —common
335 —source voltage joystick (positive 12 volt dc)
336 —USB
337 —USB
338 —180 volt dc bus voltage measurement/input
338 A—voltage transducer
339 , 339 A—communication between IQAN MD3-C1 and IQAN MD3-C2
340 —positive (+) 12 volt dc
341 —address tag
342 —address tag
343 —RS 232 communication terminal
344 —RS 232 communication terminal
345 —negative (−) 12 volt dc supply
346 —digital output enabling CR 5
347 —digital output enabling brake
348 —digital output enabling 180 volt dc power to motor/DMOC
349 —Switch, i.e., Relay, IGBT (Insulated Gate Bipolar Transistor), or other solid state device
349 C—pulse width modulation signal
349 D—resistor power dissipation in % and Watts
349 E—measured battery voltage, volt dc
349 G—198 volts dc
350 —negative (−) input terminal
351 —shunt
352 —positive (+) 12 volt dc voltage input to IQAN MD3-C1 processor
353 —socket relay terminal on IQAN MD3-C1
354 —negative (−) 12 volt dc voltage input to IQAN MD3-C1
355 —communication terminal to DMOC motor controller
356 —communication terminal to DMOC motor controller
357 —communication terminal to IQAN XA2
358 —communication terminal to IQAN XA2
359 —communication terminal to IQAN MDC3-C1
360 —communication terminal to IQAN MDC3-C1
361 —negative (−) 12 volt dc terminal to battery meter and prescaler
362 —shunt terminal connection
363 —shunt terminal connection
364 —prescaler connection
365 —positive (+) 12 volt dc terminal to battery meter and prescaler
366 —CAN communication
367 —CAN communication
368 —ground
369 —positive (+) 12 volt dc terminal
370 , 371 —voltage transducer power supply
374 , 375 —12 volt dc output of converter
378 , 379 —CAN communication
382 , 383 —12 volt dc supply to battery monitor
391 —battery
391 A—ultra-capacitor
400 —control panel
402 —key/switch
403 —level wind control
404 —brake pressure indicator
405 —brake control
406 —master control interface
407 A—torque control decrease
407 B—torque control increase
420 —directional indication
430 —puller mode push button, F 1
431 —tension mode push button, F 2
432 —diagnostic push button, F 3
500 —180 volt dc control schematic flow chart
500 A—motor control schematic flow chart
500 B—tension mode schematic flow chart
501 —master start
502 —joystick lever centered?
503 —holding brake off?
504 —enable 180 volt dc circuit, energize CR 6 , CR 2 and CR 3
505 —motor control
506 —puller/tensioner automatically shutdown
507 —input speed=0 if machine was automatically shutdown
508 —input speed and direction (pay-out or pull-in) joystick controlled
509 —upper torque set by depressing right button (increase) or left button (decrease)
510 —tension mode?
511 —torque reset button pressed?
512 —display confirmation message of torque reset?
513 —user confirmation of torque reset?
514 —reset upper torque to zero
515 —lower torque equals zero
516 —lower torque equals upper torque in tension mode
517 —conversion of speed and upper and lower torque to motor controller
518 —transmit converted values to DMOC motor controller using CAN Bus
519 —mathematically process input and upper torque values for display
520 —display input speed and torque values
521 —receive actual speed and torque values from DMOC motor controller using CAN Bus
522 —mathematically process actual speed and torque values for display
523 —display actual speed and torque values
524 —tension mode
525 —tension function key F 2 pressed?
526 —joystick lever pulled back?
527 —enter tension mode, display green lamp
528 —receive battery voltage from DMOC motor controller via CAN Bus
529 —mathematically process battery voltage for display
530 —display batter voltage
531 —calculate resistor bank PWM duty cycle
532 —enable resistor bank, energize CR 5
533 —display PWM duty cycle as a %
534 —measure batter temperature
535 —mathematically process battery temperature for display
536 —display battery temperature
537 —is battery temperature greater than 120 degrees Fahrenheit?
538 —apply holding brake
539 —shut machine down
Those skilled in the art will recognize that the invention has been set forth by way of examples. As such, changes may be made to the invention has described and disclosed herein without departing from the spirit and the scope of the invention as claimed hereinbelow.
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A line stringing apparatus includes in combination an electric motor, motor controller and a processor switchable between a pulling mode and a tensioning mode. An electric motor expends electrical energy when pulling the line and generates electrical energy when tensioning the line. The processor outputting commands to the motor controller for control thereof and for application of electrical energy from the batteries to the electric motor when in the pulling mode and for application of electrical energy generated by the electric motor to the plurality of batteries when in tensioning mode. The processor limits electric motor torque and speed based on operator commands for speed and torque in said pulling mode; and, the processor controlling electric motor torque in the tensioning mode.
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FIELD OF THE INVENTION
This invention relates to a novel adduct of an epoxy resin and an hydroxy-free acrylate resin. The adduct is a homogeneous, essentially gel-free liquid at room temperature. Tough, thermoset compositions having low water absorption and low mold shrinkage may be prepared by co-curing the adduct with an ethylenically unsaturated monomer.
BACKGROUND OF THE INVENTION
Hydroxy-free acrylate resins are known articles of commerce. U.S. Pat. No. 4,327,013 describes the preparation of thermoset compositions using hydroxy-free acrylate resins. Such resins are typically co-polymerized with an ethylenically unsaturated monomer, especially styrene, to provide a comparatively inexpensive composition having relatively good mechanical strength properties. Hydroxy-free acrylate thermosets are further characterized by exhibiting low shrinkage upon molding and low water absorption.
Epoxy resins are similarly well known. Thermoset compositions prepared with epoxy resin normally have a higher service temperature and mechanical strength in comparison to acrylate resin thermosets, but are also generally more expensive. Furthermore, epoxy resins are prone to water absorption.
It is clear that a new material having a balance of the desirable properties exhibited by epoxy and acrylate resins would be a useful addition to the art. However, the two resins are prone to separate into two phases when attempts are made to co-cure them.
It has now been surprisingly discovered that a liquid adduct of a selected epoxy resin and a hydroxy-free acrylate resin may be prepared by reacting the epoxy and hydroxy-free acrylate in the presence of an amine or onium salt catalyst. The resulting adduct may be co-cured with a monoethylenically unsaturated monomer to provide a thermoset coating or molding composition.
SUMMARY OF THE INVENTION
The present invention provides an adduct of
i) an epoxy resin having from 2 to 4 epoxy functional groups and a molecular weight from 300 to 600, and
ii) an hydroxy-free acrylate resin according to the formula: ##STR1## wherein R is the hydroxy-free residue of a polyhydric alcohol, R 1 and R 2 are independently hydrogen or methyl, n is from 1 to 3, and the molecular weight of said hydroxy-free acrylate resin is from 200 to 600 characterized in that said adduct is prepared by reacting said epoxy resin and said hydroxy-free acrylate resin in the presence of a catalyst selected from (a) an amine and (b) and onium salt according to the formula: ##STR2## where M is selected from elemental nitrogen and elemental phosphorous, X is selected form bromine, chlorine and iodine, and R a , R b , R c and R d are the same or different and are selected from the group consisting of alkyl, aryl and cycloalkyl hydrocarbons having from 1 to 20 carbon atoms.
In another embodiment of the invention, there is provided a novel thermosettable composition comprising the above identified adduct and an ethylenically unsaturated monomer.
DETAILED DESCRIPTION OF THE INVENTION
The adduct of the present invention is prepared using hydroxy-free acrylate resin according to the empirical formula ##STR3## wherein R is the hydroxy-free residue of an organic polyhydric alcohol (i.e., an alcohol having at least 2 alcoholic OH groups), R 1 and R 2 may be the same or different and are selected from hydrogen or methyl and n is from 1 to 3. For ease of reference, the resin defined by the above formula will be referred to as an "hydroxy-free acrylate resin".
Hydroxy-free acrylate resin may be prepared by the conventional reaction of a polyhydric alcohol with either a carboxylic acid (such as acrylic or methacrylic acid) or with the simple ester of the carboxylic acid (such as methyl methacrylate).
The polyhydric alcohol suitable for use herein contains from 2 to 4 -OH alcoholic functional groups and is preferably an alkane polyhydric alcohol or an aromatic ring-containing polyhydric alcohol. Illustrative examples of suitable polyhydric alcohols include: diethylene glycol (also known as dihydroxy-di-ethyl ether), dipropylene glycol; 1,4 butane diol and 2,2-bis (4-hydroxyphenol) propane.
The hydroxy-free acrylate resin may also be prepared with more than one of the above-described polyhydric alcohols. Specific examples of preferred hydroxy free acrylate resin include ethoxylated bisphenol A dimethacryalte, propoxylated bisphenol A dimethacrylate, triethylene glycol dimethacrylate and diethylene glycol dimethacrylate.
An epoxy resin is also required to prepare the adduct of the present invention. The term "epoxy resin" is used herein to convey its conventional meaning (i.e., a molecule having more than one α-epoxy group: Handbook of Epoxy Resins, Lee and Neville, McGraw-Hill, 1967). Illustrative examples of suitable epoxy resins include diglycidyl/bisphenol A epoxies, such as the diglycidyl ether of bisphenol A, glycidyl ethers of novolac resins and (cyclo)aliphatic epoxies. Highly preferred epoxies have from 2 to 4 epoxy groups and a molecular weight between 350 and 500.
The adducts of the present invention are homogeneous, essentially gel free liquids at room temperature. They contain residual vinyl unsaturation which can be observed by proton nmr spectroscopy. This vinyl unsaturation allows co-curing of the present adducts with one or more ethylenically unsaturated monomers.
While not wishing to be bound by any particular theory, it is believed tht the reaction which provides the adducts of the present invention proceeds as follows: ##STR4##
It will be noted that the above reaction does not require vinyl unsaturation, nor any hydroxyl group.
The present adducts are prepared with a selected amine or Onium salt catalyst.
Amines which can open an epoxy group are suitable for use in the present invention. The use of a tertiary amine catalyst is highly preferred in comparison to the use of a primary or secondary amine, as primary and secondary amines have a strong tendency to gel the adduct and can only be employed with great caution. Particularly preferred amines are pyridine and diazabicyclo (2.2.2) octane ("DABCO").
Suitable onium salt catalysts are defined by the formula: ##STR5## where M is selected from elemental nitrogen and elemental phosphorous, X is selected from bromine, chlorine and iodine and R a , R b , R c and R d are the same or different and are selected from the group of alkyl, aryl and hydrocarbons having from 1 to 20 carbon atoms.
The terms "quaternary ammonium salt" and "quaternary phosphonium salt" are commonly used to describe compounds encompassed by the above formula.
Preferred examples of the onium salt catalyst are tetrabutyl ammonium bromide ("TBAB"), tetrabutyl phosphonium bromide ("TBPB"), tetrabutyl ammonium iodide ("TBAI") and benzyl triethyl ammonium chloride ("BTEAC") of which TBAB is especially preferred.
The above amine and onium salt catalysts are capable of causing gel in a mixture of epoxy and hydroxy-free acrylate resins,if the catalyst concentration or reaction temperature is too high. This is an undesired phenomenon which can be avoided by selecting a suitably low catalyst concentration and/or reaction temperature.
It is preferred to use amine catalyst in an amount between 0.5 and 2.5 weight percent (based on the combined weight of the epoxy and hydroxy-free acrylate resin) at a temperature between 100° and 125° C. for a time between 2 and 4 hours. Onium salt catalysts are preferably used in comparatively higher concentrations (10 to 15 weight percent, based on the combined weight of the epoxy and hydroxy-free acrylate resin), at a temperature between 90 and 100° C. for reaction times of 8 to 25 hours.
The adducts of the present invention are preferably prepared using an epoxy resin/hydroxy-free acrylate resin weight ratio between 3/1 and 1/3. Highly preferred adducts are prepared using equal weights of epoxy and hydroxy-free acrylate resin.
Thermosettable compositions may be prepared by mixing a curative system with the adduct and at least one ethylenically unsaturated copolymerizable monomer which is miscible with the adduct. The term "ethylenically unsaturated monomer" refers to a monomer which contains a
--CH═C< or/and a CH.sub.2 ═C< functional group. Examples of preferred monomers include styrene and its derivatives and homologues; vinyl acetate; and "acrylate" monomers (i.e. esters of acrylic or methacrylic acid) such as methyl methacrylate and butyl acrylate.
Styrene is the most preferred ethylenically unsaturated monomer for preparing the present thermoset compositions.
The weight ratio of adduct/ethylenically unsaturated monomer in preferred thermoset compositions is from 1/2 to 2/1. Thermoset compositions prepared with higher levels of unsaturated monomer are prone to mold shrinkage while thermosets prepared with lower levels of unsaturated monomer tend to be glassy and brittle.
Curing of the adduct and unsaturated monomer is completed using a curative which acts on both the unsaturated monomer and the adduct. Preferred curative systems consist of a free radical curative (especially a peroxide) and an epoxy curative. Suitable free radical curatives include: t-butyl perbenzoate, t-butyl peroctoate, di-butyl peroxide and methyl ethyl ketone peroxide and are preferably utilized in an amount of between 0.5 and 3.0 weight percent. Suitable epoxy curatives include methylene dianiline, cyclohexane dicarboxylic acids or anhydrides thereof and Lewis acids which are soluble in the adduct and are preferably utilized in an amount between 2.0 and 70.0 weight percent.
The present thermoset compositions are useful as coatings and as molding compounds. Thermoset molding compounds may optionally include conventional ingredients such as reinforcing fibres (especially fibreglass or aramid fibres), fillers, pigments, low profile additives and elastomeric toughening agents.
Thermoset molding compositions prepared according to the present invention have good fracture toughness, good mechanical strength properties and exhibit low mold shrinkage and low water absorption.
Further details of the invention are illustrated by the following non-limiting examples, in which all parts and percentages are by weight unless otherwise indicated.
EXAMPLE 1
This example illustrates the preparation of an adduct of a diglycidyl/bisphenol A epoxy having an average molecular weight of 330 to 350 (sold under the tradename DER 332 by Dow Chemical) and ethoxylated bisphenol A dimethacrylate having a theoretical molecular weight of 342 (sold under the tradename SR 348 by Sartomer). The epoxy resin and hydroxy-free acrylate were used in a weight ratio of 10:13 (respectively).
The inventive adducts of experiments 1 to 4 inclusive were prepared by reacting the epoxy resin and hydroxy-free acrylate in a stirred round bottom flask at 95° C., for 24 hours, in the presence of an onium salt catalyst. The amount of catalyst used in each experiment is shown in Table 1.
The reaction flask was flushed with dry nitrogen before the reaction ingredients were added, and was heated in an oil bath. The flask was covered with a septum containing a needle hole puncture during the reaction.
The resulting adducts were homogeneous (i.e. they did not separate into distinct phases upon standing for more than 7 days at room temperature) and essentially gel free (i.e. they did not contain visible gel).
Thermoset molding compounds were prepared by mixing the adduct with styrene (1/1 weight ratio) and curing with 1,8 diamo-octane plus tertiary butyl perbenzoate (3 weight percent and 1 weight percent, respectively, based on the total weight of adduct plus styrene). The compounds were cured at 80° C. for 4 hours, then 90° C. for 16 hours and 150° C. for 2 hours in a simple mold consisting of two flat glass sheets separated by a rubber gasket.
Properties of the cured compositions of this and the following compositions were determined according to the procedures described below.
Rectangular-shaped test specimens were prepared from the molded sheets for mechanical property testing (fracture toughness and flexural strength).
The fracture toughness specimens had dimensions of 7.0 cm×0.9 cm×0.15 cm (i.e. length×width×thickness) and a single edge notch 0.3 cm deep. The flexural strength specimens had dimensions of 3.5 cm×0.9 cm×0.15 cm.
The testing was completed on a conventional materials tester sold under the tradename JJ Lloyd Tensile Tester at a crosshead speed 0.1 cm per minute.
The critical stress intensity factor (" 1c ") was determined as a measure of "fracture toughness" or alternatively stated, "impact resistance". K 1c is calculated according to the linear elastic fracture mechanics equation:
K.sub.1c =Si×Y×(a.sub.o).sup.0.5
where a o is the crack length and Si is the stress at initiation of unstable crack propagation:
Si=(Maximum force to break the specimen)/(t×w) where w and t are the original width and thickness of the specimen, respectively;
Y is the geometry factor:
Y=1.99-0.41(a.sub.o /w)+18.79(a.sub.o /w) .sup.2 -38.48(a.sub.o /w).sup.3 +53.85(a.sub.o /w) .sup.4
Further discussion of K 1c is given in "Compendium of Stress Intensity Factors" (Rooke, D.R. and Cartwright, D.J., Procurement Executive, Ministry of Defense, U.K.)
Flexural strength was calculated as follows: Flexural strength =[1.5×Maximum force to break specimen ×L] [W×t 2 ]
where w, t and L are the original width, thickness and span length of the specimen, respectively.
Flexural modulus was calculated as follows:
Flexural modulus=[m×L 3 ]×[4×w×t 3 ])
where m is the initial slope of the stress vs strain curve.
Table 1 provides a summary of the experiments of this example.
Experiments 5 and 6 are comparative. The compositions of the comparative experiments were prepared by mixing the epoxy, hydroxy-free acrylate, styrene and TBAB just before curing (i.e. the epoxy and hydroxy-free acrylate were not pre-reacted to form an adduct). The curatives and curing cycles used for the comparative experiments were the same as those used for the inventive experiments.
The fracture toughness and flexural properties of the inventive compositions are clearly superior to the corresponding properties of the comparative compositions.
Water absorption characteristics were simply measured by weighing a sample of the cured resin, immersing it in water for 7 days at room temperature and reweighing the sample. The observed weight increase was attributed to water uptake. The results were converted to weight percentages (basis measured increased in weight/original sample weight) and are reported as "water uptake" in this and the following examples (note: a "-" symbol indicates water uptake was not measured).
TABLE 1__________________________________________________________________________ TBAB Flexural Flexural Water Catalyst Strength Modulus K.sub.1c UptakeExperiment (Wt. %) (MPa) (GPa) (MPa · m.sup.1/2) Remarks (wt %)__________________________________________________________________________1 13.0 121.87 ± 2.94 ± 1.20 ± 0.82 4.46 0.19 0.112 6.5 133.34 ± 3.79 ± 1.29 ± 0.59 6.59 0.25 0.103 5.2 108.51 ± 3.03 ± 1.29 ± -- 20.57 0.12 0.104 3.5 121.33 ± 3.67 ± 1.20 ± -- 28.89 0.23 0.14 5* 13.0 104.21 ± 3.08 ± 0.69 ± Phase -- 22.04 0.06 0.12 separation upon curing 6* 13.0 105.49 ± 2.87 ± 0.67 ± Phase -- 5.79 0.15 0.12 separation upon curing__________________________________________________________________________ *comparative
EXAMPLE 2
This example illustrates the use of different types of onium salt catalysts to prepare adducts. The inventive adducts of experiments 10 to 13 inclusive were prepared by reacting 10 parts by weight of diglycidyl/bisphenol A epoxy (sold under the tradename DER 332 by Dow Chemical) with 13 parts by weight ethoxylated bisphenol A dimethacrylate (sold under the tradename SR 348 by Sartomer), in the presence of the catalysts indicated in table 2. The adducts of inventive experiments 14 to 18 inclusive were prepared using a novolac type epoxy (sold under the tradename DEN 431 by Dow Chemical), instead of the diglycidyl ether/bisphenol A epoxy used in experiments 10 to 13.
The reaction conditions for inventive experiments 10 to 16 were the same as those described in Example 1. The adducts of the inventive experiments were mixed with styrene and then cured using the same curatives and cure cycles described in Example 1.
Properties of the cured compositions are shown in Table 2.
Experiments 17 and 18 are comparative. The molded composition of experiment 17 was prepared without catalyst, while the composition of experiment 18 was prepared by mixing epoxy, hydroxy-free acrylate, styrene and catalyst just prior to curing (i.e. without first forming an adduct). 10 parts by weight of diglycidyl/bisphenol A epoxy and 13 parts by weight of ethoxylated bisphenol A dimethacrylate were used in both of experiments 17 and 18.
TABLE 2__________________________________________________________________________ Amount Flexural Flexural WaterExperi- Catalyst Strength Modulus K.sub.1c Uptakement Catalyst (Wt. %) (MPa) (GPa) (MPa · m.sup.1/2) (wt %)__________________________________________________________________________10 Tetrabutyl 13.0 121.87 ± 2.94 ± 1.20 ± 0.82 ammonium bromide 4.46 0.19 0.1111 Tetrabutyl 14.0 121.56 ± 3.20 ± 1.26 ± 0.71 phosphonium bromide 6.24 0.20 0.1212 Benzyltriethyl 9.1 116.24 ± 3.74 ± 0.81 ± -- ammonium chloride 30.40 0.14 0.0213 Tetrabutyl 14.5 144.38 ± 3.28 ± 1.27 ± 0.98 ammonium iodide 3.52 0.17 0.0914 Tetrabutyl 13.0 140.23 ± 3.36 ± 1.27 ± -- ammonium bromide 5.36 0.09 0.0415 Tetrabutyl 14.0 122.72 ± 3.54 ± 1.11 ± -- phosphonium bromide 0.74 0.45 0.1116 Benzyltriethyl 9.1 135.44 ± 3.66 ± 1.12 ± -- ammonium chloride 14.86 0.22 0.13 17* None 0.0 143.77 ± 3.65 ± 0.65 ± -- 6.64 0.16 0.08 18* Tetrabutyl 13.0* 103.32 ± 3.24 ± 0.90 ± -- ammonium bromide 31.41 0.19 0.05__________________________________________________________________________ *comparative
EXAMPLE 3
This example illustrates the use of amine catalysts to prepare adducts.
The inventive adducts of experiments 20 and 21 were prepared by reacting 10 parts by weight of diglycidyl ether/bisphenol A epoxy (sold under the tradename DER 332 by Dow Chemical) with 13 parts by weight of ethoxylated bisphenol A dimethacrylate (sold under the tradename SR 348 by Sartomer), in the presence of the amine catalysts indicated in table 3. The reaction was undertaken for 2 hours at 110° C., using the reaction equipment described in Example 1. The adducts were then mixed with an equivalent weight of styrene and the mixture was cured using the curatives and curing cycles described in example 1 (except for experiment 21, wherein 1.4 weight percent tertiary butyl perbenzoate was used in place of the 1.0 weight percent tertiary butyl perbenzoate used in the experiments of example 1).
Comparative experiment 22 was completed using the type and amounts of expoxy and acrylate resin used in experiment 20, but without pre-reacting the epoxy and acrylate to form an adduct.
TABLE 3______________________________________ Amount Flexural WaterExperi- Catalyst Strength K.sub.1c Uptakeiment Catalyst (Wt. %).sup.a (MPa) (MPa · m.sup.1/2) (wt. %)______________________________________20 DABCO 1.0 128.41 ± 1.28 ± 0.38 5.49 0.1221 Pyridine 1.7 123.13 ± 1.23 ± 0.52 3.36 0.16 22* DABCO 1.0 107.25 ± 0.73 ± -- 4.96 0.25______________________________________ *Comparative .sup.a Based on combined weight of epoxy plus hydroxyfree acrylate.
EXAMPLE 4
This example illustrates the use of different types of epoxy resins to prepare inventive adducts.
In experiments 30 to 33 inclusive, ethoxylated bisphenol A dimethacrylate ("SR 348", sold by Sartomer) was reacted for 24 hours at 95° C. with an epoxy of the type shown in Table 4, in the presence of 13 percent TBAB (based on the combined weight of the epoxy plus hydroxy free acrylate. The weight ratio of epoxy to hydroxy-free acrylate used in each experiment is also shown in table 4. Cured compositions were prepared by mixing the resulting adducts with an equivalent weight of styrene and curing using the curatives and cure cycle described in Example 1.
Properties of the cured compositions are shown in Table 4.
TABLE 4__________________________________________________________________________ Flexural Flexural WaterExperi- Epoxy/Acrylate Strength Modulus K.sub.1c Uptakement Epoxy (wt. ratio) (MPa) (GPa) (MPa · m.sup.1/2) (wt. %)__________________________________________________________________________30 bis A-1.sup.a 10:13 121.87 ± 2.94 ± 1.20 ± 0.82 4.46 0.19 0.1131 Novo.sup.b 10:13 140.23 ± 3.36 ± 1.27 ± -- 5.36 0.09 0.0432 tetra.sup.c 10:21 142.60 ± 3.28 ± 1.14 ± 1.05 5.87 0.16 0.2033 bis A-2.sup.d 10:10 123.69 ± 3.22 ± 1.05 ± -- 23.12 0.29 0.18__________________________________________________________________________ Notes: .sup.a glycidyl ether/bisphenol A epoxy (sold under the tradename DER 332 by Dow Chemical). .sup.b novolac epoxy having an average molecular weight from 330 to 350, (sold under the tradename DEN 431 by Dow Chemical). .sup.c a tetraepoxide having an average molecular weight from 410 to 430 (sold under the tradename MY720 by Ciba Geigy). .sup.d glycidyl ether/bisphenol A epoxy (sold under the tradename EPON 82 by Shell).
EXAMPLE 5
This example illustrates the use of different hydroxy-free acrylates to prepare adducts.
In experiments 40 to 43 inclusive, a glycidyl ether/bisphenol A epoxy ("DER 332", sold by Dow Chemical) was reacted for 24 hours at 95° C. with an hydroxy-free acrylate of the type shown in Table 5, in the presence of 13 percent TBAB (based on the combined weight of the epoxy plus hydroxy-free acrylate). The weight ratio of epoxy to hydroxy-free acrylate used in each experiment is also shown in Table 5. Cured molding compositions were prepared by mixing the resulting adducts with an equivalent weight of styrene and using the curatives and curing cycle described in Example 1.
Properties of the molded compositions are shown in Table 5.
The molded composition of comparative experiment 44 was prepared by curing the same ingredients used in experiment 43, but without first pre-reacting the epoxy and hydroxy-free acrylate.
TABLE 5__________________________________________________________________________ Flexural FlexuralExper- Epoxy/Acrylate Strength Modulus K.sub.1ciment Acrylate (wt. ratio) (MPa) (GPa) (MPa · m.sup.1/2)__________________________________________________________________________40 Ethyoxylated 10:13 121.87 ± 2.94 ± 1.20 ± Bisphenol A 4.46 0.19 0.11 dimethacrylate.sup.141 Ethoxylated 10:12 111.05 ± 3.22 ± 1.11 ± Bisphenol A 4.75 0.15 0.15 diacrylate.sup.242 Diethylene Glycol 10:6.2 98.25 ± 3.01 ± 1.20 ± Diacrylate.sup.3 8.15 0.24 0.1243 Trimethylolpropane 10:6.6 86.36 ± 3.55 ± 0.91 ± trimethacrylate.sup.4 21.44 0.20 0.16 44* Trimethylolpropane 10:6.6 63.58 ± 3.53 ± 0.74 ± trimethacrylate.sup.4 16.57 0.20 0.15__________________________________________________________________________ Notes: *Comparative .sup.1 Sold by Sartomer as SR348 resin. .sup.2 Sold by Sartomer as SR349 resin. (theoretical m.w. = 424) .sup.3 Sold by Sartomer as SR230 resin. (theoretical m.w. = 214) .sup.4 Sold by Sartomer as SR350 resin. (theoretical m.w. = 338)
EXAMPLE 6
This example illustrates the preparation of adducts at different reaction temperatures. In each experiment of this example, 10 parts by weight of a diglycidyl/bis.phenol A epoxy ("DER 332", sold by Dow Chemical) was reacted with 13 parts by weight of ethoxylated bisphenol A dimethacrylate ("SR 348", sold by Sartomer Limited) for 24 hours at the temperature shown in table 6 in the presence of 13 percent TBAB. Molded compositions were prepared with the adducts of experiment 50-52 inclusive by mixing with styrene and curing as described in Example 1.
In experiment 53 (not shown in Table 6), 5 percent TBAB was employed at a temperature of 130° C. The epoxy/hydroxy free acrylate mixture was visibly gelled after 20 minutes.
TABLE 6______________________________________ Reaction Temp. Flexural Flexural K.sub.1cExperiment (°C.) Strength Modulus (MPa · m.sup.1/2)______________________________________50 80 143.40 ± 3.96 ± 1.06 ± 4.92 0.58 0.0551 95 121.87 ± 2.94 ± 1.20 ± 4.46 0.19 0.1152 110 140.80 ± 3.52 ± 1.16 ± 5.34 0.25 0.10______________________________________
EXMAPLE 7
The example illustrates the use of different adduct to styrene weight ratios in the preparation of thermoset compositions according to the present invention. The use of a different ethylenically unsaturated monomer, namely para-methyl styrene and a mixture of styrene and methyl methacrylate, is also illustrated.
The adduct used in all experiments of this example was prepared by reacting 13 parts by weight of ethyoxylated bisphenol A dimethacrylate with 10 parts by weight of a diglycidyl ether/bisphenol A epoxy (DER 332, sold by Dow Chemical) in the presence of 13% TBAB for 24 hours at 95° C., as described in Example 1.
Thermoset compositions were prepared by curing the adduct with styrene (or para-methyl styrene), in the amounts shown in table 7, using the curatives and curing conditions described in example 1.
TABLE 7__________________________________________________________________________ Flexural FlexuralExperi- Adduct/Monomer Strength Modulus K.sub.1cment Monomer (wt. ratio) (MPa) (GPa) (MPa · m.sup.1/2)__________________________________________________________________________70 S 4:1 104.42 ± 3.43 ± 0.83 ± 17.72 0.13 0.1171 S 3:1 79.35 ± 3.27 ± 0.89 ± 19.76 0.27 0.0972 S 2:1 121.87 ± 2.94 ± 1.20 ± 4.46 0.19 0.1173 S 1:1 71.53 ± 2.18 ± 1.10 ± 5.17 0.25 0.1074 S 1:2 132.17 ± 3.36 ± 0.89 ± 8.99 0.31 0.1775 PMS 1:1 127.16 ± 3.12 ± 1.16 ± 5.72 0.21 0.1476 S/MMA 1:1 104.92 ± 3.39 ± 1.15 ± 7.93 0.46 0.09__________________________________________________________________________ Notes: S = Styrene PMS = Paramethyl styrene MMA = methyl methacrylate
EXAMPLE 8
In this example, 120 grams of ethoxylated bisphenol 4 dimethacrylate and 60 grams of diglycidyl ether of bisphenol A were mixed and analyzed by proton nmr spectroscopy. 8 grams of TBAB catalyst was then added to the acrylate/epoxy resins and allowed to react for 24 hours at 120° C. The resulting adduct was cooled and again analyzed by proton nmr spectroscopy. The reaction did not result in any significant change in the nmr signal attributed to the vinyl protons, indicating that the adduct contains vinyl functionality and that the reaction did not consume a significant quantity of the vinyl functional groups contained in the acrylate resin.
EXAMPLE 9
This example illustrates the use of an acrylonitrile-butadiene elastomer as an additive for molding compositions according to the present invention.
The adduct used in all of the experiments of this example was prepared by reacting 10 parts by weight of a glycidyl ether/bisphenol A epoxy (sold under the tradename EPON 828 by Shell) with 13 parts by weight of ethoxylated bisphenol A dimethacrylate (sold under the tradename SR 348 by Sartomer) for 5 hours at 120° C. in the presence of 2.5 weight percent TBAB catalyst.
The thermosettable molding compound of experiment 90 was prepared by mixing styrene and the adduct in a 1:1 weight ratio.
In experiments 91 and 92, the adduct was blended at room temperature with styrene and an acrylonitrilebutadiene rubber at a weight ratio of 45:45:10, respectively.
In experiment 93, 90 grams of the adduct was heated at 120° C. for 4 hours in the presence of 20 grams of the acrylonitrile-butadiene elastomer indicated in table 9. 90 grams of styrene was subsequently added to the adduct/elastomer to prepare a thermosettable modling composition.
The molding compositions of experiments 90 to 93 were cured using 25 weight percent cis-cyclohexane dicarboxylic acid anhydride and 1 percent t-butyl perbenzoate at 80° C. for 5 hours, followed by 16 hours at 100° C. and a final 2 hours at 150° C.
TABLE 9______________________________________Experi- Elas- Flexural Flexural K.sub.1ciment tomer Strength (MPa) Modulus (GPa) (MPa · m.sup.1/2)______________________________________90 -- 125.1 ± 3.9 2.67 ± 0.07 1.04 ± 0.0791 NBR1.sup.(i) 123.4 ± 2.1 2.62 ± 0.04 1.18 ± 0.0592 NBR2.sup.(ii) 116.2 ± 3.0 2.81 ± 0.03 1.52 ± 0.0393 NBR1 103.3 ± 1.8 2.29 ± 0.05 2.28 ± 0.04______________________________________ Notes: .sup.(i) NBR1 = vinyl terminated, liquid acrylonitrilebutadiene rubber sold under the tradename HYCAR VTBNX (1300 × 23) by B. F. Goodrich .sup.(ii) NBR2 = carboxyl terminated, liquid acrylonitrilebutadiene rubbe sold under the tradename HYCAR CTBNX (1300 × 18) by B. F. Goodrich.
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This invention provides an adduct of an epoxy resin and a hydroxy free acrylate resin. The novel adduct contains vinyl unsaturation and hence may be copolymerized with an ethylenically unsaturated monomer to provide a tough thermoset resin.
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FIELD OF THE INVENTION
The present invention relates to a screw compressor primarily for gaseous refrigerants, comprising a compressor housing, which comprises a male and a female screw rotor arranged in screw rotor bores in the compressor housing, which male and female rotor are co-rotatingly drivable and interacting for compressing the refrigerant, which screw compressor comprises at least one slider, which slider is movable in relation to the male and the female rotor, where movement of the slider controls the internal volume ratio of the screw compressor, which slider is moveable in a slider housing, which slider is in a direction sidewards to the plane formed by the rotational axes of the male and the female rotor, which slider is interacting with the male and the female rotor.
The present invention further relates to a method for controlling the discharge of a screw compressor, which compressor comprises a male and a female screw rotor arranged in screw rotor bores in the compressor housing, which male and female rotor are co-rotatingly drivable and interacting for compressing the refrigerant, where a slider is moved in relation to the male and the female rotor from a sidewards direction, which direction deviates several degrees from the longitudinal axes of rotation of the male and the female rotor, which slider is operable for controlling the discharge of the compressor.
BACKGROUND OF THE INVENTION
US2005/001302 describes a screw compressor for gaseous media, in particular refrigerants, comprising a compressor housing, two screw rotors which are arranged in screw rotor bores in the compressor housing, which are rotatingly drivable and interact to compress the medium, and a control slide arranged adjacent the screw rotors and movable in a direction of displacement for controlling the compression of the screw compressor. In order to solve the problem that the compression of the screw compressor can be controlled, but not precisely regulated, it is proposed that a scannable element, which is scannable with a measuring sensor so as to recognize a position of the control slide in the direction of displacement, is coupled with the control slide.
U.S. Pat. No. 4,913,634 describes a screw compressor in which a pair of screw rotors supported by bearings and accommodated in a casing acts to compress a gas and in which a slide valve disposed between an inner wall of the casing and the pair of screw rotors are capable of moving axially while maintaining a small gap between itself and the outer peripheries of the screw rotors, the rate of gas flow bypassed to an inlet port during compression being regulated by axially moving the slide valve. The screw compressor has a side cover in which a bearing for supporting the pair of screw rotors on the discharge side and a slide valve driving hydraulic means are incorporated and which are disposed on the discharge side of the screw rotors; a discharge axial port formed in the side cover; and at least one projection continuous with an opening edge of the discharge axial port and in contact with a semi-circular surface of the slide valve facing in the radial direction thereof, the projection acting to limit the radial movement of the slide valve while the slide valve is moving in contact with the top end of the projection
U.S. Pat. No. 4,281,975 describes a screw compressor which includes a contacting a male and female rotor with respect to which a slide valve is operable to control the discharge of the compressor and also regulate the pressure of the fluid pumped or compressed thereby, where the improvement comprises a limited number of different embodiments of anti-friction constructions for supporting the slide valve within the cylindrical bore provided therefore in the housing within which the male and female rotors operate, the wear upon the slide valve within the bore therefore is thereby minimized and the force required to move the slide valve is minimized.
U.S. Pat. No. 5,044,909 concerns a rotary compressor of a cooling or heat pump system, the inner volume relation should be related in a predetermined way to the pressure relation of the compressor for an optimal efficiency to be achieved. The built-in volume relation must therefore be variable to be adapted, for example, to full load and partial load. In order to achieve the highest efficiency with respect to loading requirements, a valve device has been developed, in which the discharge port is formed in such a way as to substantially correspond to the theoretically correct radial discharge port and in which a valve body adapted for the purpose has its line of action oriented towards the outlet plane. The valve body is arranged in such a way that in its fully inserted position in the outlet port the mantle wall will correspond to the mantle wall of the working space of the compressor, and will be adjacent to the rotors at a minimum amount of play by means of the end face having been provided with a pointed line surrounded by two concave surface. The outlet port in the mantle wall of the working space of the rotary compressor is delimited by an outlet plane of the compressor and by the screw lines in the mantle wall, which correspond to the cam surfaces of the rotors, which cam surfaces interact in the direction of the outlet plane of the compressor.
It is of the utmost importance for the valve body to move on a certain plane in order not to get into a wrong position relative to its correct position in relation to the outlet port and the outlet plane; for example, the valve body can be given, for example, a substantially circular-cylindrical cross-section, whereby a good guiding surface for the valve body is achieved.
In order for the valve body not to rotate during its movement up to the outlet port and back again, the valve body can be provided with guiding means, such as grooves. With the valve body in an inclined position relatively to the running rotors, the outlet port can be formed more or less in correspondence with the theoretical outlet port, and at the same time a fully closed sealing line between the rotor housing and the outlet plane is achieved, which also contributes towards making the rotary compressor easier to handle; for example, when the rotors are to be inspected, only the valve body has to be removed. Further, the inclined position implies forming the valve body with an oblique surface, which will move towards the outlet plane, whereby the valve body will be guided in its movement towards the outlet port and will finally be fixed in its fully inserted position.
OBJECT OF THE INVENTION
It is the object of the invention to develop a highly effective screw compressor, which screw compressor can regulate the discharge pressure.
DESCRIPTION OF THE INVENTION
This can be achieved by a screw compressor as described in the opening paragraph if the compressor comprises discharge end plates, which discharge endplates can be place between the discharge end of the male and female screw rotors and the end plate of the compressor housing, which discharge end plates comprises a discharge opening, which discharge end plates comprise discharge end walls, where the slider comprises at least two areas, which areas are cooperating with subsequent areas placed in conjunction with the discharge end walls for controlling the angular and linear placement of the slider for avoiding rotor contacts.
It can hereby be achieved that independent pressure volumes formed between the male and the female rotor during the interaction of the rotors are connected to the discharge before the last compression takes place, when this slider is moved away from its forward position. This will lead to a reduction of the discharge pressure of the compressor. This shunting of the discharge from the rotors will automatically also increase the volume of compressed gas that leaves the compressor. The sideways placement of the slider and the slider housing lead to the rotor bores in the compressor housing being formed in the housing without any cut-outs along most of the length of the rotor bores before the sideways opening for the slider housing. This can lead to a very tight screw compressor without any leaks along for example a slider operating parallel to the male and the female rotor. The screw compressor with the sideways acting slider is much cheaper to produce than the traditional screw compressors with sliding elements. It is easy to produce the two bores for the male and the female rotor and afterwards to form the sideways slider housing.
The angle of the slider and the slider housing is preferably more than 45 degrees in relation to the longitudinal rotational axes of the male and the female rotor. This can lead to an effective placement of the slider if the angle of operation is higher than 45 degrees.
The angle of the slider and the slider housing can be more than 60 degrees in relation to the longitudinal rotational axes of the male and the female rotor. It can hereby be achieved that the angle for the slider and the slider housing could be up to 90 degrees so that the slider is acting towards the male and the female rotor directly perpendicular. In certain embodiments of the invention, the angle could be the supplementary angle to the above-mentioned one.
The slider can be movable in the housing, which housing comprises at least one pressure chamber, which pressure chamber is connected to the discharge volume of the compressor, where the slider has a front surface, at which surface the pressure is forcing the slider to move backwards from the male and the female rotor. It is hereby achieved that the actual discharge pressure of the screw compressor will force the slider backwards. Means for forcing the slider in the opposite direction are can be achieved by different force acting methods and components. A primitive solution could be that the slider is operating against the pressure of a spring. This could lead to an automatic pressure adjustment of the screw compressor. Other actuating means would also be possible. An example is that a hydraulic pressure is actuating the slider into a direction towards the male and the female screw. A combination of a spring and hydraulic or gas activation would probably also be possible for pressing the slider towards the rotors.
The housing can comprise at least a second pressure chamber, which second pressure chamber contains a back surface of the slider for forcing the slider to move forwards towards the male and the female rotor. It is hereby achieved that a pressure chamber is placed behind the slider, and this pressure chamber can be activated for example by refrigerant. In this way, the compressor can operate without use of an extra media for activation.
The front of the slider can be placed in the first pressure chamber, which front of the slider has an active pressure surface, which pressure surface is smaller than the active pressure surface of the back surface of the slider placed in the second pressure chamber. It is hereby achieved that the back-side pressure can be controlled so that this pressure can achieve nearly all pressure values between the suction pressure of the compressor and the discharge pressure of the compressor. In this way, the slider can be activated with a pressure that can be regulated to every value between these two outer limits. This can lead to a possible solution where the slider is placed in different positions between two outer positions.
The second pressure chamber can be connected through an orifice towards the suction side of the compressor, which second chamber further is connected through a first electromagnetic valve to the discharge pressure of the compressor. This will lead to a constant pressure reduction in the second chamber to achieve an inlet pressure in that chamber if the electromagnetic valve is closed.
The first electromagnetic valve can be connected to an electronic circuit comprising computer means. It can hereby be achieved that an increase of the pressure in the second chamber can be achieved by periodical opening of the electromagnetic valve. Depending on the size of the previously described orifice and the opening of the electromagnetic valve, the pressure in the second chamber can achieve a value that maximally is very close to the discharge pressure of the compressor. This pressure will then always move the slider forwards.
It is hereby possible that the computer takes over the control of the discharge pressure for the compressor. These computer means can also comprise further means for controlling a motor, which drives the compressor. If the motor is an electromotor, a kind of semiconductor switches will probably be used.
The slider can cooperate with at least one mechanical stop when the slider is placed in a forward position for increasing the discharge pressure of the compressor. This assures that the slider will not come in touch with the rotors in the compressor. By using this stop, a very effective and very close position towards the rotors can be achieved.
The invention further comprises a method for controlling the slider, where a discharge opening is formed in discharge endplates, where the discharge endplates comprises discharge end walls, where the slider comprises guiding areas which areas interacts with corresponding areas placed in conjunction with the discharge end wall for controlling the angular and linear placement of the slider when the slider is operating adjacent to the rotors at a minimum amount of play towards the male and the female screw rotor.
In this way, the interaction between the slider and the male and the female rotor can be made only in a limited area near the pressure end of the male and the female rotor. In fact, the slider can when it is away from interaction make a shortcut between the two last compression volumes formed between the male and the female rotor. This shortcut will lead to an increasing volume and a decreasing pressure at the pressure discharge. The sideways interaction reduces the number of possible leaks that typically occur if a slider operates along the male and the female screw rotor. This parallel slider will end up in a very difficult construction of the compressor. Furthermore, there will be very small openings towards the slider, and these openings can be a kind of shortcuts that is decreasing the effectiveness of the compressor.
The slider can move from a first position to a second position in a slider housing, which slider housing can be placed at an angle of more than 45 degrees in relation to the longitudinal rotational axes of the male and the female rotor. This relatively high angle is effective because the slider housing has limited influence on the construction of the rest of the compressor housing.
The angle of the slider and the slider housing can be more than 60 degrees in relation to the longitudinal rotational axes of the male and the female rotor. A still steeper angler for the slider seems more and more effective. The limitation for this patent application is as such not 90 degrees, even slider angles over 90 degrees would be possible in a certain embodiment, depending on which end of the compressor that is connected to a driving motor.
The slider can be movable by the discharge pressure, which discharge pressure acts on the effective area of the front surface of the slider to force the slider to move backwards from the male and the female rotor. By letting the slider be movable backwards of the discharge pressure of the compressor, an automatic pressure control can easily be achieved. As soon as the slider is moved backwards, the output pressure is reduced, and then the pressure of the front end of the slider is reduced. Depending on which activation means that are placed in conjunction with the slider, it could be moved forward, for example by a spring, or it could be moved forward by other activation means which could be hydraulic or also mechanical or electromagnetic means would be possible. Even a kind of analogue pressure regulation could be formed in this way because it would be possible to let the slider take a position where a certain pressure occurs, where there is a limited effect on the slider and where a backwards movement of the slider will reduce the effect of the slider.
The backside of the slider can be under influence of a pressure, which pressure can be regulated to force the slider to move forwards towards the male and the female rotor. It is hereby achieved that a pressure on the backside will move the slider forwards. This pressure can be hydraulic where for example high pressure oil from the compressor could be used, or it is possible to use the high pressure refrigerant delivered from the discharge of the compressor as the medium.
The front side of the slider has an active pressure surface, which pressure surface is smaller than the active pressure surface of the back surface of the slider. It is hereby achieved that a smaller pressure of the backside in relation to the pressure of the front side can keep the slider in a kind of balance. Increasing pressure on the backside will move the slider forwards, and decreasing pressure will move the slider backwards.
The pressure in the second pressure camber can be decreased by an orifice connected towards the suction side of the compressor, which pressure in the second chamber further is controlled by a first electromagnetic valve connected to the discharge pressure of the compressor. By using an orifice to decrease the pressure and a magnetic valve to increase the pressure, it will be possible to adjust the pressure in the chamber between the suction pressure of the compressor and the discharge pressure of the compressor. The orifice can have an opening that is relatively small in relation to the opening degree of the magnetic valve. This will lead to an increasing pressure as soon as the magnetic valve is opened, but in the other way, as soon as the magnetic valve is closed, the pressure will start decreasing in the chamber. Depending again on the size of the orifice, this pressure decrease can be relatively slow which will let the slider move relatively slowly. This can automatically lead to a dampening of oscillations of the slider.
An electronic circuit comprising computer means can control the first electromagnetic valve. Computer means can hereby control the opening degree of the magnetic valve. It would be possible that the computer means controls the valve in a way of modulation so that different positions of the slider could be obtained.
The slider can be controlled by one mechanical stop, when the slider is placed in a position for increasing the discharge pressure of the compressor. The mechanical stop is necessary if the slider shall be operating very closely to the rotating male and female rotor. Only by using a stop, it will be possible to come that close to the rotating elements, which are necessary for making an effective compression. The distance between the slider and the rotating rotors should be limited to the size of an oil film.
DESCRIPTION OF THE DRAWING
FIG. 1 shows a sectional view of a part of a screw compressor
FIG. 2 shows a enlarged sectional view of the part of a screw compressor shown at FIG. 1 ,
FIG. 3 shows a sectional view of the same elements as seen in FIG. 2
FIG. 4 shows an enlarged view of FIG. 3 .
FIGS. 5 , 6 and 7 show the same components in different situations,
FIGS. 8 , 9 and 10 show the slider in its forward position
FIGS. 11 , 12 and 13 show an alternative embodiment
FIG. 12 shows a compressor housing and a slider housing.
FIGS. 14 , 15 , and 16 show the same embodiment as the one shown in FIGS. 11 , 12 , and 13 .
FIG. 17 shows an inner slider
FIG. 18 shows an outer slider
FIG. 19 shows the same embodiment as the one shown in FIG. 11 , were the rotors are shown above the sliders.
FIG. 20 shows the same embodiment as the one shown in FIG. 12 , where the rotors 0 are shown
FIG. 21 is an enlarged view of FIG. 20
FIG. 22 shows a compressor which has a suction pipe connected to the suction side of the compressor.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a sectional view of a screw compressor 2 comprising a housing 4 , which comprises a bore 6 , which contains the male 8 and the female 10 rotors. A slider housing 20 comprises a slider 22 which slider 22 has a front area 24 placed in a pressure chamber 26 . Furthermore, the slider 22 comprises a backside 28 placed in a second pressure chamber 30 . FIG. 1 shows moreover a channel 32 connected to the suction side of the compressor.
In operation, the slider 22 can be moved away from interaction with the male 8 and the female 10 rotors in the rotor housing 6 . The slider 22 is shown in its forward position where the slider front has a form that is equal to the form of the housing 6 , but on the front surface of the slider 22 , the pressure volume 26 is acting. The discharge pressure of the compressor will here try to force the slider 22 to perform a backwards movement in the slider bore 20 . This backwards movement will reduce the second volume 30 , which can be connected through a not shown orifice. This will automatically lead to a dampening of the movement of the slider 22 . By changing the pressure in the second chamber 30 , the back surface 28 of the slider can come under pressure, which will press the slider 22 back to its position where it is in touch with a stop.
FIG. 2 shows a sectional view of the part of a screw compressor, which comprises the previously described slider. In FIG. 2 , a slider 122 is shown which slider 122 has a front surface 124 placed in conjunction with a pressure chamber 126 . The backside 128 of the slider 122 is placed in a second pressure chamber 130 . The discharge pressure port 140 is placed in a discharge endplate 141 , where the discharge port 140 cooperates with a cut-out 146 in the front of the slider 122 . The slider 122 has a surface 152 , which cooperates with a surface 156 placed in conjunction with the discharge port 140 of the screw compressor. A guiding-in 160 cooperates with a groove 162 which groove 162 is formed in the backside 128 of the slider 122 .
In FIG. 2 , the slider 122 is pressed backwards away from the discharge port 140 by the discharge pressure. It is hereby achieved that the discharge port 140 is increased in size along the discharge end of the male and female rotors so that the pressure chambers in the end of the volumes between the two rotors are connected to the outlet. This leads to a reduced pressure and a higher flow of gas.
FIG. 3 shows a sectional view of the same elements as seen in FIG. 2 but seen from the upper side of FIG. 2 . FIG. 3 shows a compressor housing 104 and a slider housing 120 . Inside, the discharge port 140 is placed in the discharge endplate 141 . Furthermore, the surfaces 142 , 144 of front end of the slider 122 . Between the two surfaces 142 , 144 , the cut-out 146 is shown.
FIG. 4 shows an enlarged view of FIG. 3 . The discharge port 140 in the discharge endplate 141 is shown, and the front end of the slider 122 is shown with its surface 142 , 144 . The number 148 indicates the centre line of the compressor housing, and the number 150 indicates the centre line of the slider 122 . The slider 122 has a surface 152 and a further surface 154 . The end surface 152 cooperates with a surface 156 placed in conjunction with the discharge opening in the compressor. Further, the end surface 154 will cooperate with a surface 158 also in conjunction with the pressure outlet.
As already mentioned for FIG. 2 , it is also indicated in FIGS. 3 and 4 that the slider 122 is placed in its backwards position. In this position, in FIG. 4 a difference between the centre line 150 of the slider and the centre line 148 of the housing is shown. This indicates that the slider is rotated out of its optimal position when it is placed in its backwards position. This leads to a large opening between the surface 154 and the surface 158 .
FIGS. 5 , 6 and 7 shows exactly the same components as already mentioned for FIGS. 2 , 3 and 4 . The difference between the figures is that the slider 122 is now placed in a position between its two end situations. This can be seen in FIG. 5 where the front of the slider 124 is closer to the housing of the rotors. But especially in FIG. 7 , the function taking place when the slider is moved downwards is indicated. The slider 122 has been moved forwards so its surface 152 and its surface 154 are rather close to get in touch with the corresponding surface 156 and the surface 158 at the corresponding surfaces at the compressor outlet components. Also, the line 150 in relation to the line 148 is now partly aligned. The open area formed by the cut-out 146 in the slider is now reduced because the opening along the front 124 of the slider is smaller.
FIGS. 8 , 9 and 10 show the slider 122 in its forward position. The front end 124 of the slider 122 is now parallel with the inner wall of the rotor housing. The surface 152 of the slider 122 is now in touch with the surface 156 . This is further indicated in FIG. 10 where the surface 152 and the surface 156 are now in touch, and the surface 154 and the surface 156 are also touching each other. It is indicated that the centre line 148 of the compressor housing and the centre line 150 of the slider are now totally aligned. It is also indicated that the opening 146 is now reduced.
By using the direct touch of the slider with the discharge pressure components having the surfaces 156 and 158 , this will lead to a nearly perfect alignment of the slider 122 when it is in its front position. This is absolutely necessary; otherwise the slider 122 could get in mechanical touch with the rotating screws.
FIGS. 11 , 12 and 13 show an alternative embodiment where a slider housing 220 contains an inner slider 222 and an outer slider 223 . The inner slider has a back end 228 , which cooperates with a pressure chamber 230 . The outer slider 223 has an end 229 , which cooperates with a pressure chamber 231 . The slider 222 has a surface 252 which cooperates with a surface 256 formed at the pressure outlet. The outer slider 223 has a surface 253 , which cooperates with a surface 257 at the pressure outlet of the compressor.
In FIG. 12 , a compressor housing 204 and a slider housing 220 are seen. The slider 222 has a front surface 242 , 244 , and the slider 223 has surfaces 243 , 245 . In FIG. 13 , an enlarged view of the central part of FIG. 12 is shown. FIG. 13 shows a pressure outlet opening 240 placed in the discharge endplate 241 . The slider 222 has end surfaces 242 , 244 . The slider 223 has surfaces 243 , 245 . The surface 252 cooperates with a surface 256 at the discharge endplate 241 , where the surface 253 cooperates with a surface 257 . Further, the surface 254 cooperates with a surface 258 . Also the surface 255 cooperates with a surface 259 . A centre line of the housing 248 , a centre line 250 of the slider 222 and the centre line 251 of the slider 223 are shown.
In operation, it is possible to force the slider 222 backwards by reducing pressure in the chamber 230 . This will reduce the discharge pressure of the compressor. Further reduction of the discharge pressure can be achieved by also forcing the slider 223 backwards. This can be achieved if the slider 222 is moved, and the pressure in the chamber 231 is reduced. The two sliders 222 , 223 can be moved back in their front position by first increasing the pressure in the chamber 231 and afterwards increasing the pressure in the chamber 230 . Hereby, it is achieved that a compressor can be adjusted in at least three different steps. It will probably be possible to also achieve analogue discharge control of the compressor by placing one of the sliders or maybe both sliders in a position between the minimum or maximum positions.
FIGS. 14 , 15 , and 16 show the same embodiment as the one shown in FIGS. 11 , 12 , and 13 . Components already mentioned above will not be mentioned again in the following.
The difference between the embodiment shown in FIGS. 11 , 12 , 13 and the embodiment shown in FIGS. 14 , 15 , 16 is that the sliders 222 and 223 in the latter are shown in their backward position. A working chamber 233 is now visible under the backside 229 of the slider 233 . Further, the chamber 231 is visible between the backside 229 of the outer slider and the backside 228 of the inner slider. From FIG. 16 it appears that the outer slider has a front edge 255 which can engage with the edge 259 at the discharge end plate 241 . The inner slider also has a front edge 254 which can engage with the edge 258 positioned on the edge of the discharge end plate 241 . Furthermore the edge 252 at the inner slider is shown which will cooperate with the edge 256 at the edge of the discharge end plate 241 . Further, the outer slider has a front edge 253 which will cooperate with the edge 257 at the discharge end plate 241 . Further in FIG. 16 , the centre line 248 for the compressor house 204 and the centre line 250 of the inner slider can be seen. It is clearly indicated that the inner slider is misaligned in the angular and sideward position in relation to the centre line 248 .
In operation this misalignment is harmless in the backward position shown. However, when the sliders 222 , 223 is moved into contact with the discharge end plate 241 , both sliders 222 , 223 will be aligned.
FIG. 17 shows an inner slider 222 which has contact areas 242 and 244 for being aligned when they engages with the discharge end plate 241 . Furthermore edges 252 , 254 are shown which are positioned in such a way that they will engage the edge of the discharge end plate 241 .
FIG. 18 shows an outer slider 223 which comprises contact areas 243 and 245 for engaging with the discharge end plate 241 when it is in its forward position of the slider. Further contact areas 253 and 255 are shown. These contact areas will engage the edge of the discharge end plate 241 .
FIG. 19 shows the same embodiment as the one shown in FIG. 11 , the difference being that the rotors are shown above the sliders.
FIG. 20 shows the same embodiment as the one shown in FIG. 12 , the difference being that the rotors 208 and 210 are shown.
FIG. 21 is an enlarged view of FIG. 20 and also shows the two rotors 208 and 210 .
FIG. 22 shows a compressor 302 which has a suction pipe 382 connected to the suction side of the compressor. The compressor 302 has a discharge pipe 378 which is connected to an oil management system 376 from which refrigerant is flowing to a pipe 380 . In the compressor 302 one of the rotors 308 and 310 can be seen. A slider 322 can also be seen. This slider has a front area 324 which engage the rotors 308 and 310 . The slider has a backside 328 , which is placed in a working chamber 380 . The working chamber 330 is connected to the chamber 333 through a flow-restriction 370 . From chamber 333 there is a connection towards the compressor to a point in the compressor having a relatively low pressure P 4 . The chamber 330 is further connected to a line 371 to a magnetic valve 372 and further to a line 374 to the oil management system 376 .
In operation, the discharge pressure P 2 will be present at the area A 1 , which is the front of the slider 322 . This pressure P 2 working on A 1 will press the slider backwards. In the chamber 333 a pressure P 4 is operating which is slightly above P 1 , which is the suction pressure of the compressor. The flow-restriction unit 370 also connects the pressure P 4 to the chamber 330 so that oil can flow from this chamber through the flow-restriction unit 370 towards the chamber 333 and from here towards the compressor at the pressure P 4 .
If the valve 372 is open, oil will flow through the line 374 through the valve 372 and further through the line 371 towards the chamber 330 . The high-pressure oil also flows through the flow-restriction 370 , but in an amount so that the pressure in the chamber 330 will increase. This increasing pressure P 5 will now, due to its increase, move the slider 332 forwards. This will bring the slider into its operational forward position where the slider is engaging the rotors and the discharge area at the end of the rotors is reduced. By using oil for hydraulic activation and de-activation of the slider it is achieved that a medium usually applied in the compressor can also be used for this hydraulic activation. By using the oil there will be no leakages for refrigerant and as such no reduction in the amounts of refrigerant, which can be supplied over line 380 to a refrigeration system.
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The present invention relates to a screw compressor and a method for operating the compressor primarily for gaseous refrigerants, comprising a compressor housing ( 4 ) and a male ( 8 ) and a female ( 10 ) screw rotor arranged in screw rotor bores in the compressor housing ( 4 ), which male and female rotor are co-rotatingly drivable and interacting for compressing the refrigerant, which screw compressor comprises at least one slider ( 22 ) movable in relation to the male and the female rotor, where movement of the slider controls the internal volume ratio of the screw compressor, which slider is moveable in a slider housing ( 20 ) in a direction sideways to the plane formed by the rotational axes of the male and the female rotor, which slider, interacting with the male and the female rotor, comprises at least two surfaces ( 152, 154 ) cooperating with subsequent surfaces ( 156, 158 ) placed in conjunction with the slider housing for controlling the angular and linear placement of the slider in its forward position.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent application Ser. No. 11/065,465, filed Feb. 24, 2005, which published as Publication No. 2005/0139995, which is itself a continuation-in-part of U.S. patent application Ser. No. 10/924,586, filed Aug. 24, 2004, now U.S. Pat. No. 7,048,039, which is itself a continuation of U.S. patent application Ser. No. 10/458,168, filed Jun. 10, 2003, now U.S. Pat. No. 6,793,009, the content of each of which is incorporated herein by reference in its entirety. This application also incorporates herein by reference U.S. Provisional Patent Applications Nos. 60/561,436, filed Apr. 12, 2004, and 60/574,158, filed May 25, 2004, in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to heat sinks having mounting surfaces for semiconductors, and more particularly to such heat sinks which include one or more mounting surfaces having a coefficient of thermal expansion that matches or nearly matches silicon.
BACKGROUND
[0003] It is known that certain classes of semiconductor devices consume substantial amounts of power, which results in excess thermal energy that then must be transferred to the ambient environment. This waste heat is typically communicated through a variety of thermal interfaces, heat spreaders, and structural elements prior to being rejected into the ambient atmosphere by a heat sink. Since heat is often dissipated to room temperature air, and the silicon constructed semiconductor has a finite upper bound on its operating temperature, package-related thermal resistance is becoming a limiting factor in the ability to dissipate the waste heat.
[0004] The removal of package elements and interfaces will reduce package thermal resistance, and allow the semiconductor device to either run cooler or dissipate more power. However, many of these elements are required in order to provide a match between the relatively low coefficient of thermal expansion (CTE) of silicon and the relatively high CTE of the metal comprising the heat sink, rather than for best thermal performance. This match needs to be maintained in order to prevent build-up of stress, as well as subsequent damage due to failure of the relatively brittle silicon component. Thus, there are the competing structural requirements of providing a layer of material to provide a CTE match while at the same time needing to bring the heat transfer structure into intimate physical contact with the heat generating structure.
[0005] Matching may be achieved by at least two methods: the use of an alloy substrate such as copper/tungsten whose CTE matches or nearly matches that of the silicon, or through the use of a ductile braze alloy between the silicon and the remaining package elements. Either method prevents transmission of stresses due to mismatched CTE through the interface to the silicon device. Some disadvantages of the alloy substrate include expense, unfavorable machining and stamping characteristics, and a fairly low thermal conductivity. Some disadvantages of the ductile braze alloy include a limited fatigue life, which eventually results in failure due to delamination of the joint. This tendency is exacerbated by the service conditions of most high power devices. Such devices almost always operate under conditions of periodic fluctuating electrical load, which leads to periodic fluctuations in thermal load and mechanical stresses in the joint.
[0006] An alternative method involves the use of direct bond copper (DBC) aluminum nitride (AlN) in sheet form. This material is a “sandwich” comprised of a single layer of aluminum nitride and two outer layers of OFE copper foil. The copper layers are first oxidized, and then pressed against the AlN at high temperature in a neutral atmosphere. This process causes the oxide to diffuse into the AlN and bonds the copper sheets tightly to the AlN inner layer. Since the copper layers are relatively thin and are in an annealed state due to the high processing temperature, the CTE of the resulting assembly is largely governed by that the of the AlN.
[0007] None of the foregoing techniques have been found to be completely satisfactory or have been successfully applied to heat pipe cooling devices.
SUMMARY
[0008] In one embodiment, a heat transfer device generally includes an interior chamber defined at least in part by a layered-composite wall. The layered-composite wall includes a first layer of material comprising a coefficient of thermal expansion that is substantially similar to the coefficient of thermal expansion of silicon. The first layer is disposed between and directly engages second layers of material comprising a coefficient of thermal expansion greater than the coefficient of thermal expansion of silicon. The wall has a periphery that is out of plane with respect to a remainder of the wall.
[0009] In another embodiment, a heat pipe generally includes a body defining an interior chamber, a wick disposed on portions of the body that define the interior chamber, and a working fluid. The interior chamber is defined at least in part by a layered-composite wall. The layered-composite wall includes a first layer of material comprising a coefficient of thermal expansion that is substantially similar to the coefficient of thermal expansion of silicon. The first layer is disposed between and directly engages second layers of material comprising a coefficient of thermal expansion greater than the coefficient of thermal expansion of silicon. The wall has a periphery that is out of plane with respect to a remainder of the wall.
[0010] In a further embodiment, a heat pipe generally includes a body defining an interior chamber, a wick disposed on portions of the body that define the interior chamber, and a working fluid. The interior chamber is defined at least in part by a layered-composite wall of molybdenum disposed between layers of oxygen-free electronic copper foil. The wall has a periphery that is out of plane with respect to a remainder of the wall.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiments of the invention, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein:
[0012] FIG. 1 is a partly exploded, elevational view of a CTE-matched heat pipe formed in accordance with one embodiment of the present invention;
[0013] FIGS. 2-4 are cross-sectional perspective views of the CTE-matched heat pipe of FIG. 1 ;
[0014] FIG. 5 is a broken-away cross-sectional view of a portion of the low CTE base illustrated in FIGS. 2-4 ;
[0015] FIG. 6 is a perspective view of a composite base comprising a high CTE portion and a complementary low CTE insert portion positioned for placement within an opening;
[0016] FIG. 7 is an exploded cross-sectional view of a composite base, as taken along lines 7 - 7 in FIG. 6 ;
[0017] FIG. 8 is a cross-sectional view of the assembled composite base shown in FIG. 7 ;
[0018] FIG. 9 is a cross-sectional view of another embodiment of composite base having a wick applied to a surface of a low CTE insert portion;
[0019] FIG. 10 is a cross-sectional view of yet another embodiment of composite base having a wick overlying a low CTE insert portion;
[0020] FIG. 11 is a cross-sectional view of a further embodiment of a CTE-matched base;
[0021] FIG. 12 is a cross-sectional view of tower heat pipe having a low CTE composite insert positioned within a high CTE base;
[0022] FIG. 13 is a perspective view of another embodiment of composite base having a plurality of low CTE inserts;
[0023] FIG. 14 is a perspective view of a planar heat pipe heat spreader formed in accordance with another embodiment of the present invention;
[0024] FIG. 15 is a cross-sectional view of the embodiment of composite base shown in FIG. 14 , as taken along lines 15 - 15 in FIG. 14 ;
[0025] FIG. 16 is an enlarged view of the cross-section shown in FIG. 15 ;
[0026] FIG. 17 is a perspective view of a planar heat pipe comprising a composite wall formed in accordance with another embodiment of the invention;
[0027] FIG. 18 is a cross-sectional view of the planar heat pipe shown in FIG. 17 , as taken along lines 19 - 19 in FIG. 17 ;
[0028] FIG. 19 is an enlarged cross-sectional view of the interior wall structures of a planar heat pipe formed in accordance with the present invention;
[0029] FIG. 20 is a perspective view of a semiconductor device mounted on the planar heat pipe shown in FIGS. 17-18 ;
[0030] FIG. 21 is a cross-sectional view of the planar heat pipe shown in FIG. 20 , as taken along lines 21 - 21 in FIG. 20 ;
[0031] FIG. 22 is an enlarged cross-sectional view of the interior wall structures of a planar heat pipe formed in accordance with the present invention;
[0032] FIG. 23 is a perspective view of a planar heat pipe comprising a composite wall and a low CTE insert formed in accordance with another embodiment of the invention;
[0033] FIG. 24 is a cross-sectional view of the planar heat pipe shown in FIG. 23 , as taken along lines 24 - 24 in FIG. 23 ;
[0034] FIG. 25 is an enlarged cross-sectional view of the interior wall structures of a planar heat pipe formed in accordance with the present invention;
[0035] FIG. 26 is a perspective view of a planar heat pipe comprising a composite wall and a low CTE insert formed in accordance with another embodiment of the invention;
[0036] FIG. 27 is a cross-sectional view of the planar heat pipe shown in FIG. 26 , as taken along lines 27 - 27 in FIG. 26 ;
[0037] FIG. 28 is an enlarged cross-sectional view of the interior wall structures of a planar heat pipe formed in accordance with the present invention;
[0038] FIG. 29 is a cross-sectional view of yet a further embodiment of a planar heat pipe having a composite wall structure formed in accordance with the present invention; and
[0039] FIG. 30 is an enlarged cross-sectional view of the interior wall structure of a planar heat pipe formed in accordance with the present invention.
DETAILED DESCRIPTION
[0040] This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.
[0041] Referring to FIGS. 1-4 , a CTE-matched heat pipe 5 formed in accordance with one embodiment of the present invention includes a body 8 , a wick 12 , a working fluid 13 , and a base 15 . More particularly, body 8 may comprise a cylindrical tube formed from a highly thermally conductive metal, e.g., copper or its alloys or nickel or its alloys such as Monel (an alloy of nickel and copper) which could be incorporated into the structure with no significant changes in design or fabrication method. A vapor space is defined by a central passageway 20 extending along the longitudinal axis of body 8 . Body 8 includes a bottom end 22 and a top end 24 . Top end 24 is pinched off or otherwise sealed at a fill tube 26 during manufacture. Wick 12 is preferably formed from a brazed copper powder that is distributed throughout the inner surface of body 8 that defines central passageway 20 at bottom end 22 . Although not preferred, wick 12 may be distributed throughout the inner surface of body 8 at top end 24 , and may also comprise adjacent layers of screening or a sintered powder structure with interstices between the particles of powder, having an average thickness of about 0.1 mm to 1.0 mm.
[0042] In one preferred embodiment of the present invention, no wick structure is present at top end 24 (the condenser region of heat pipe 5 ). This is due in large part to the fact that gravity will drive the return of condensed working fluid 13 in the particular orientation shown in FIGS. 1-4 . A wick structure may be incorporated in top end 24 , i.e., in the condenser region of heat pipe 5 , in order to provide return of condensate when the evaporator portion of the heat pipe is oriented so as to be above the condenser region. A wick structure in top end 24 may also reduce the temperature drop associated with condensation, as well as improve performance of the device, even when the wick is not required to return the working fluid.
[0043] Wick 12 may also include a screen or grooves integral with the inner surface of body 8 . Also, a plastic-bonded wick in the evaporator and condenser regions of heat pipe 5 may be produced simultaneously and as a contiguous structure after body 8 is brazed to base 15 . This would provide a contiguous fluid conduit between the evaporator and condenser regions of heat pipe 5 , which is advantageous when the evaporator is elevated. This feature may be met with a screen wick by “pushing” the screen wick into an annular gap 28 located between bottom end 22 and base 15 .
[0044] Working fluid 13 may comprise any of the well known two-phase vaporizable liquids, e.g., water, alcohol, Freon, methanol, acetone, fluorocarbons or other hydrocarbons, etc. CTE-matched heat pipe 5 is formed according to the invention by drawing a partial vacuum within body 8 , and then back-filling with a small quantity of working fluid 13 , e.g., just enough to saturate wick 12 just prior to final sealing of body 8 by pinching, brazing, welding or otherwise hermetically sealing fill tube 26 , once base 15 is mounted to bottom end 22 of body 8 . The atmosphere inside heat pipe 5 is set by an equilibrium of liquid and vapor.
[0045] Base 15 comprises a plurality of layers of selected materials so as to form a layered-composite having a low CTE, i.e., a CTE that nearly matches the CTE of a semiconductor, such as about 6.5 or less for silicon ( FIG. 1 ). For example, base 15 may be formed from a direct bond copper (DBC) aluminum nitride. Base 15 may comprise a variety of shapes that could be dictated by both the geometry of the semiconductor device 30 that is to be cooled by CTE-matched heat pipe 5 , or the shape of bottom end 22 of body 8 . Base 15 is fastened directly to bottom end 22 of body 8 without the use of intermediate layers of CTE matching materials or ductile brazes. A base 15 formed from DBC aluminum nitride possesses several advantages that make it attractive for use as an interface to silicon semiconductor devices and substrates. As no interposing intermediate layers of CTE matching materials or ductile brazes are needed, bottom end 22 of CTE-matched heat pipe 5 will be arranged in intimate thermal communication with semiconductor device 30 . The interface between bottom end 22 and semiconductor device 30 will also be significantly more resistant to thermal cycling and thermal fatigue. DBC aluminum nitride base 15 comprises high thermal conductivity, both in-plane and through-thickness, and its conductivity approaches that of aluminum. Thus, the construction of the present invention allows bottom end 22 of CTE-matched heat pipe 5 to approach the chip more closely, i.e., more closely than any method other than direct die contact or direct liquid cooling, so that the package thermal resistance is as low as possible.
[0046] In another embodiment, base 31 may include a plurality of layers to form a layered-composite 38 comprising a layer of molybdenum 37 having a top surface 39 and a bottom surface 40 ( FIG. 5 ). A first layer 42 of OFE copper foil is disposed over top surface 39 and a second layer 43 of OFE copper foil is disposed over bottom surface 40 so as to form layered-composite 38 ( FIGS. 2-5 ). In this way, a layered composite is formed comprising a first layer 42 of relatively high CTE material (i.e., a CTE higher than that for silicon), a second layer 43 of relatively high CTE material (i.e., a CTE higher than that for silicon), and an intermediate layer 37 of relatively low CTE material, thus forming layered-composite 38 having an internal structure comprising high CTE material/low CTE material/high CTE material. The CTE of such a layered-composite is often in a range from about 2.5 to about 10, with a range from about 3 to about 6.5 being preferred for most silicon applications.
[0047] When the present invention comprises a layered-composite 38 formed from layers of copper/molybdenum/copper, a thickness ratio of 13%/74%/13% has been found to provide adequate results. A copper/molybdenum/copper layered-composite 38 comprises mechanical properties that are suitable for higher temperature processing. This allows a silicon die to be attached to base 31 , via soldering, without structural instability which may cause the silicon to crack or break.
[0048] Table 1 below presents thermal conductivity and CTE properties of different common materials that may be arranged as a layered-composite 38 in conformance with the present invention. In tower applications, it is preferred that the high CTE layers of material be selected so that base 15 may be fastened directly to bottom end 22 of body 8 without the use of any intermediate low CTE materials.
[0000]
Coefficient Thermal
Material
Expansion (ppm/° C.)
Silicon Carbide
2.6
Silicon
2.6
Molybdenum
4.9
Graphite
5
Beryllium Oxide
8
Annealed Copper
16.4
Aluminum Nitride
3.6
80Mo20Cu
7.2
75W25Cu
10.2
33Cu/74Mo/33Cu
10
13Cu/74Cu/13Cu
6.5
[0049] A brazed wick 33 may be formed on the inner surface of base 15 or 31 . Depending upon the heat load and particular power density, other wick structures may be appropriate. Examples of such structures include screen bonded to the heat input surface by spot-welding or brazing, a monolayer of powder metal, grooves cut in the copper layer of base 31 , or an array of posts. Furthermore, it is also anticipated that a plastic-bonded wick may be substituted for the brazed copper wick.
[0050] In practice, semiconductor 30 is mounted to the bottom surface of base 31 . Heat from semiconductor 30 is conducted through base 31 into bottom end 22 of heat pipe 5 . The heat causes working fluid 13 in wick 12 to evaporate. The vapor travels through central passageway 20 to condenser region 35 of body 8 . At condenser region 35 , the vapor contacts the inner surface of body 8 , condenses, and gives up its latent heat through condensation. Working fluid 13 then returns to bottom end 22 by either gravity, or through the capillary action in a portion of wick 12 on the inner surface of body 8 at condenser 35 .
[0051] As shown in FIGS. 1-4 , fins 36 or other suitable extended surfaces may be mounted to body 8 at condenser region 35 to convey the heat to the ambient environment. It is anticipated that other fin types and structures are possible, including a folded fin wrapped around a cylindrical heat pipe envelope, an array of plate fins mounted radially around the condenser, or an array of fins mounted to the top of the device.
[0052] Referring to FIGS. 6-12 , a base 44 is also provided by the present invention in which a relatively low CTE layered-composite insert 45 is positioned within a relatively high CTE cold plate 50 , such as a copper plate. An opening 55 is formed within cold plate 50 that includes a counter-sunk region that provides an annular ledge 60 and a substantially vertical wall 62 ( FIGS. 6-8 ). Layered-composite insert 45 is positioned within opening 55 and fixedly fastened in intimate thermal communication with annular ledge 60 and vertical wall 62 so as to complete base 44 . Layered-composite insert 45 and cold plate 50 may be bonded together using conventional methods, such as brazing, soldering, adhesives, or direct bond attachment. Layered-composite insert 45 comprises a plurality of layers wherein the layers may include OFEcopper/aluminum nitride/OFEcopper, copper/molybdenum/copper, or even copper/graphite (Table 1). In a preferred embodiment, layered-composite insert 45 includes an intermediate layer 37 of molybdenum, a top layer 42 of copper and a bottom layer 43 of copper, and may be formed with a periphery that conforms or is complementary to the geometric “foot-print” of semiconductor device 30 , e.g., square, rectangular, circular or ellipsoidal, etc. When mounted, the surface of semiconductor device 30 only makes thermal contact with a top mounting surface 47 of layered-composite insert 45 .
[0053] Referring to FIGS. 9-12 , a capillary wick 33 may be formed on a surface of layered-composite insert 45 . Also, layered-composite insert 45 may be complementarily formed or machined so as to have a central prominence 48 projecting upwardly into opening 55 , thereby to improve engagement with annular ledge 60 and vertical wall 62 ( FIG. 11 ). In this way, the top or bottom surfaces of layered-composite insert 45 may be arranged in coplanar relation with a top or bottom surface of cold plate 50 . Of course, central prominence 48 may project beyond the top or bottom surfaces of any cold plate in order to form a land for engaging a semiconductor package. Also, wick 33 may be formed and arranged so as to overlie the entire outwardly facing surface of layered-composite insert 45 while only covering an adjacent portion of base 44 . Of course, wick 33 may be formed and arranged so as to overlie the entire surface of layered-composite insert 45 and base 44 .
[0054] Referring to FIG. 13 , a base 87 may include a plurality of layered-composite inserts 45 within a single high CTE cold plate 50 . Each low CTE layered-composite insert 45 may be joined to cold plate 50 in any one, or a combination of the foregoing fixation methods.
[0055] Referring to FIGS. 14-22 a planar heat pipe 100 may be formed in accordance with the present invention having one or more walls that comprise at least one of a copper/molybdenum/copper or copper/aluminum nitride/copper layered-composite substantially similar in structure to that of layered-composite portion 45 . For example, a planar heat pipe 100 may include a first plate 105 and a second plate 110 that are hermetically sealed at their respective peripheral edges so as to define a vapor chamber 112 . Vapor chamber 112 is partially evacuated and back filled with a suitable two-phase working fluid, e.g., water, Freon, ammonia, etc. A wick 120 is disposed upon one or more of the surfaces of the internally facing walls that together define vapor chamber 112 .
[0056] In another embodiment, planar heat pipe 130 may be formed so as to include one or more layered-composite inserts 45 ( FIGS. 23-28 ). Either first plate 105 or second plate 110 may define one or more openings that are closed by the introduction of layered-composite inserts 45 .
[0057] Referring to FIGS. 29-30 , a heat transfer base 135 comprises a first plate 140 and a second plate 143 arranged to form a planar heat pipe. One or more openings in first plate 140 are hermetically sealed by the introduction of a layered-composite insert 45 . Each opening in first plate 140 is formed within first plate 140 by a piercing or forming process so as to form an outwardly projecting, annular wall 147 . In one example, high CTE cold plate 135 comprises a copper sheet that has been pierced so as to draw an outwardly projecting, substantially annular wall 147 defining an outwardly facing, annular surface 150 . The peripheral top or bottom surface of layered-composite insert 45 is arranged so as to engage annular surface 150 of annular wall 147 , and the two are fixedly bonded to one another by any of the aforementioned conventional techniques, such as brazing, soldering, adhesives, or direct bond attachment. Wick 33 may be formed within the closed recess in cold plate 135 that is defined by layered-composite 45 and annular wall 147 .
[0058] It is to be further understood that the present invention is by no means limited only to the particular constructions herein disclosed and shown in the drawings, but also comprises any modifications or equivalents within the scope of the claims.
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Heat sinks having a mounting surface with a coefficient of thermal expansion matching that of silicon are disclosed. Heat pipes having layered composite or integral composite low coefficient of expansion heat sinks are disclosed that can be mounted directly to silicon semiconductor devices.
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CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to an improvement in the sensitivity of a position sensitive gamma ray detector or gamma camera. More specifically, the invention describes a method of and an apparatus for producing useful position information from Compton scattered photons in a position sensitive gamma ray detector.
2. Description of the Related Art
Gamma-ray imaging is a useful tool in many areas of science, particularly in the biological and medical fields. For example, the radioisotope Technetium 99 m can be caused to be preferentially absorbed in tumors. The location of such a tumor in the body can be determined by forming an image of the 140 keV photons emitted by the decay of the isotope. Conventional lenses cannot focus such high-energy photons and typical x-ray detectors are relatively insensitive to them. Accordingly, the image is formed using a closely packed array of collimators. The image is read out using a position sensitive gamma-ray detector. When a photon is absorbed by the detector, its x- and y-position is determined and the corresponding x- and y-position in the image array is incremented by one. The image brightness is thus proportional to the number of photons absorbed by each pixel. The detector must discriminate between photons that have come directly from the source and those that have been randomly scattered. Because the scattered radiation is lower in energy than the unscattered radiation, the detector must have some degree of energy resolution. Such detectors are often scintillators such as NaI or semiconductors such as CdTe, CdZeTe, Hgl, or germanium.
The most commonly used gamma cameras are based on scintillators, but it has long been recognized that a semiconductor detector with better energy resolution might give better images. Because germanium gamma-ray detectors have good absorption efficiency and extremely good energy resolution, many attempts have been made to manufacture a position sensitive germanium detector for this application.
One of the earliest practical cameras was described by Kaufman, et al., IEEE Trans. Nucl. Sci, NS-22, 395, 1975. This camera used a planar germanium gamma-ray detector with collecting electrodes formed as an array of narrow strips. The strips on each side were orthogonal to those on the other side. Thus, the signal from the strips on one side gives the x-position and the signal from the strips on the other side gives the y-position. If the strips are of equal width, then the effective pixel is a square with sides equal to the strip width.
Good position resolution requires the pixels to be small, usually one to three millimeters on each side. If the arriving 140 keV photon is absorbed by a photoelectric event, then the signal will be a valid event for forming the image. However, even if the germanium detector is thick enough to interact with most of the arriving 140 keV photons, the small effective detector area means that photons interacting by Compton scattering, even through a small angle, will be lost to that particular pixel. The signal produced will be smaller than the original photon energy, indistinguishable from those scattered in the body, and will thus be lost to the measurement. Because approximately one-half of the interacting photons at 140 keV are Compton scattered, the sensitivity of the detector is reduced.
Accordingly, there is a need for a system that is capable of measuring gamma rays that undergo Compton scattering.
Therefore, it is an object of this invention to provide a signal processing means and apparatus that greatly reduces the loss of sensitivity caused by Compton scattering in a gamma camera.
BRIEF SUMMARY OF THE INVENTION
When photons are absorbed in matter by Compton scattering, the maximum amount of energy that can be deposited in a single scattering event is given by the following equation: E max = E in - 511 ( 2 + 511 E in )
where E max is the energy deposited in the detector in keV and E in is the incident photon energy in keV. Equation 1 shows that, for energies up to 511/2 keV, the maximum energy deposited is less than one-half of the incident photon energy. For the 140 keV photon considered here, the maximum energy deposited in the detector for a single scattering event is about 50 keV. When one of these incoming photons is completely absorbed in two separate pixels in the detector, the sum of the pixel energies identifies the incoming photon as a valid unscattered event. The detector pixel that produces the lowest value of energy is the first interaction site and therefore the position that should be used to form the image. At energies higher than 511/2 some fraction of the incident photons will Compton scatter depositing more than half the incident photon energy. For energies up to several hundred keV that fraction will be small, thus statistically the pixel producing the smaller energy is still the pixel that should be used to form the image. Thus, by suitable processing of the signals, a large fraction of the otherwise unusable Compton scattered events are used to form the image, greatly improving the sensitivity of the camera. The figures and descriptions that follow will describe the method and apparatus required to correctly process such signals and achieve the increase in sensitivity.
The maximum increase in sensitivity and signal-to-background ratio is achieved by processing valid two pixel interactions by the preferred method described above. A somewhat simpler system can be used that gains much of the sensitivity of the preferred method. In the simpler system both pixels are used to form the image. One of the pixels is the correct image point and thus improves the sensitivity. The other pixel is randomly distributed over nearby image points and thus adds background counts. Because the background is distributed over a number of pixels and contributes no structure to the image it is clear that the overall image quality is improved. It is the intent of the present invention to include both methods, however, the preferred method is shown in the drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:
FIG. 1 depicts an orthogonal strip position sensitive radiation detector according to the prior art;
FIG. 2 is a block diagram of the prior art electronics used to form an image from the gamma rays absorbed by the prior art detector of FIG. 1;
FIG. 3 is a flow chart of the prior art method used to form an image using the prior art detector and electronics of FIGS. 1 and 2;
FIG. 4 a depicts a sectional view of the absorption of a photon in two separate pixels of the prior art detector of FIG. 1;
FIG. 4 b depicts a top plan view of the absorption of a photon in two separate pixels of the prior art detector of FIG. 1;
FIG. 5 is a block diagram of the preferred embodiment of the electronics used to form an image from the gamma rays absorbed by the detector of FIG. 1 according to this invention; and
FIG. 6 is a flow chart of the preferred embodiment of the method for forming an image using the detector of FIG. 1 and the electronics of FIG. 5 according to this invention.
DETAILED DESCRIPTION OF THE INVENTION
There is shown in FIG. 1 an orthogonal strip position sensitive radiation detector, or detector, 10 according to the prior art. A body of a semiconductor 15 , for example high purity germanium, has a first plurality of rectifying strip contacts 20 defining an x-position and a second plurality of rectifying strip contacts 30 disposed at right angles to the first contacts 20 thereby defining a y-position. Assume that there are m strip contacts 20 and n strip contacts 30 . Each strip contact has an associated preamplifier. The m x-axis preamplifiers, arranged in a bank, 40 are connected to the m x-axis position contacts 20 . The n y-axis preamplifiers, arranged in a bank, 50 are connected to the n y-axis position contacts 30 . Thus, there are m+n total preamplifiers and m×n possible combinations of x- and y-positions. The detector 10 is reverse biased by the bias voltage 60 such that a depletion region, free of mobile charge carriers, exists throughout the semiconductor 15 . While the drawings and descriptions thereof reference a germanium orthogonal strip gamma ray detector used for medical imaging, it will be recognized by those skilled in the art that the methods described apply to many other types of detectors and other imaging applications. In particular, it is well known that if multiple images of the same source are taken at different angles, a computer-aided reconstruction can give a three-dimensional view of the source.
When a gamma ray photon 70 is absorbed by the detector 10 , a quantity of mobile charge carriers is created in the detector 10 . The number of charge carriers is proportional to the energy of the photon 70 . Assuming the absorption process is a single point interaction, the charge carriers are localized at a point of (X, Y)=(i, j) in the semiconductor 15 . The charge carriers move, under the influence of the electric field created by the bias voltage 60 , to the nearest contact strips 20 , 30 . A signal is thus produced on the i th x-axis strip contact 20 and the j th y-axis strip contact 30 . The i th x-axis preamplifier 40 and the j th y-axis preamplifier 50 integrate the signal current and produce a signal voltage step proportional to the energy of the photon 70 . Because these signals occur at essentially the same time, coincidence logic circuits known to those skilled in the art can be used to qualify a valid event.
FIG. 2 shows a block diagram of the prior art signal processing electronics 100 . The signals from the x-axis preamplifiers 40 and the y-axis preamplifiers 50 are processed by a timing and control block 130 . When the timing and control block 130 determines that the signals are coincident in time, with only one x and one y, i.e., a valid single photon detection event, the corresponding strip numbers are placed in the x-position register 140 and the y-position register 150 . For the assumed event, the x-position register 140 would contain the number i and the y-position register 150 would contain the number j.
The timing and control block 130 then internally switches the signal from the j th y-axis preamplifier 50 to a shaping amplifier 170 . The shaping amplifier 170 filters and shapes the signal from the connected y-axis preamplifier 50 to produce a low-noise voltage pulse whose amplitude is proportional to the energy absorbed by the detector 10 . An analog-to-digital converter 180 measures the amplitude of the pulse from the shaping amplifier 170 and sends the resulting digital signal to a window logic block 190 . The window logic block 190 determines if the signal is within the range expected from the detector 10 for a photon having the characteristic energy of the radioisotope used to form the image. If, for example, the characteristic energy is 140 keV and the detector 10 has energy resolution of plus or minus 1 keV, then the window logic block 190 produces an output signal only if the input signal is in the range of 139 keV to 141 keV.
An image array processor 160 contains an array of m×n memory locations corresponding to the pixels in the image. When the image array processor 160 receives a valid event strobe from the window logic block 190 , the x-position register 140 and the y-position register 150 are read and the appropriate memory location is incremented. In the current example, the memory location (i, j) would be incremented.
After processing a large number of events, the image array processor 160 memory cells contain numbers corresponding to the received image. A display 165 produces a visual image corresponding to the information in the image array processor 160 . Typically the brightness of a given pixel on the display 165 is proportional to the number of counts in the corresponding memory cell. Alternatively, a color scale where different colors represent the image intensity could be used.
The flow chart of FIG. 3 is an alternative way of describing the prior art logic of FIG. 2 . The acquisition of an image is started by the operator at step 200 . The program loops at step 210 waiting for a valid event producing an (X, Y) pair. When a valid (X, Y) pair is detected, the program moves to step 220 . In step 220 , the energy of the absorbed photon is measured and compared with the predetermined energy window. If the measured energy is not within the window, i.e., the measured energy represents scattered or background photons, the event is rejected and the program returns to the loop at step 210 . If the measured energy is within the window the appropriate image array memory element is incremented in step 230 . In step 240 , a terminating condition is tested and, if met, the program proceeds to step 250 and stops. Exemplary terminating conditions include a preset time, a preset number of total counts, and an operator decision. If the terminating condition is not met the program returns to the loop at step 210 .
FIGS. 4 a and 4 b represent the case when the incoming photon is Compton scattered in the first pixel it strikes and then loses the rest of its energy in a photoelectric event in some other pixel. FIG. 4 a shows a cross-section view of the detector 10 . The photon 70 comes through the collimator and scatters in a first pixel 260 at (X, Y)=(i, k). The scattered photon 70 a is absorbed in a second pixel 261 at (X, Y)=(j, l) depositing the remainder of its energy. Because photons move at the speed of light, the interactions appear coincident in time to the processing electronics. According to Equation 1, the energy absorbed in the first pixel 260 must be less than the energy absorbed in the second pixel 261 .
FIG. 4 b is a top view of the same pair of interactions. A first set of pixels 260 , 261 , located at (X, Y)=(i, k) and (j, l), respectively, are marked with the symbol “*”. A second set of pixels 262 , 263 , located at (X, Y)=(i, l) and (j, k), respectively, are marked with the symbol “@”. Time coincident signals are processed by x-axis preamplifiers 40 i and j and by y-axis preamplifiers 50 k and l. From the timing information alone, distinguishing between the valid pair of pixels 260 , 261 and the invalid pair of pixels 262 , 263 is not possible. However, by measuring the energy signal from each preamplifier 40 , 50 , it is possible to determine which pair is valid. For a given pixel, the energy measured by the corresponding x-axis preamplifier 40 and the corresponding y-axis preamplifier 50 is the energy deposited in that pixel. Thus, the first pixel 260 is determined to be correct by noting that the energy measured by x-axis preamplifier i, E(X i ), and the energy measured by y-axis preamplifier k, E(Y k ), are essentially identical. Similarly, the second pixel 261 is valid because E(X j ) and E(Y l ) are essentially identical. The first pixel 260 can be determined to be the pixel where the interaction first occurred because, according to Equation 1, the energy deposited in the first pixel 260 is less than that deposited in the second pixel 261 .
Pixels 260 and 261 represent a valid two pixel interaction only if the total energy absorbed by the detector 10 corresponds to the original photon energy emitted by the gamma ray source. If the gamma ray 70 is scattered before reaching the detector 10 or if the two interactions do not absorb the total energy, the absorbed energy will be less than the original photon energy. By summing the x- or the y-energy signals from the first set of pixels 260 , 261 and comparing the sum to the predetermined energy window, pixels 260 and 261 are qualified as a valid two pixel interaction with pixel 260 the preferred image forming location.
The above description covers the general case for absorption of the photon energy in two but no more than two separate pixels. Having identical X or Y values is also possible for the two pixels. In either of these cases there is no ambiguity in selecting the two pixels. If the X values are the same the appropriate x-axis preamplifier 40 gives the total energy absorbed while the two y-axis preamplifiers 50 distinguish between the two pixels. The y-axis preamplifier 50 with the lowest energy value determines the preferred pixel to use in forming the image. If the Y values are the same the appropriate y-axis preamplifier 50 gives the total energy absorbed while the two x-axis preamplifiers 40 distinguish between the two pixels. The x-axis preamplifier 40 with the lowest energy value determines the preferred pixel to use in forming the image.
In addition to the single pixel interactions measurable by the prior art systems, it is thus clear that additional valid interactions are measurable and can be used to form the image. Use of these interactions requires the following procedure:
1. The energy must be deposited in two and only two pixels. Time coincident signals are produced by two x-axis preamplifiers and two y-axis preamplifiers, one x-axis preamplifier and two y-axis preamplifiers, or two x-axis preamplifiers and one y-axis preamplifier.
2. If the pixels have distinct values of both X and Y, thus producing four possible pixels, then the correct pixel pair is selected by matching the energies measured by the correct x-axis and y-axis preamplifiers.
3. The total energy deposited must be that of the photon in question. Summing the energy deposited in the two pixels must result in a total that is within the energy window.
4. The image location of the interaction is determined by selecting that pixel in which the lowest energy is deposited. In the simplified method both pixels would be used.
FIG. 5 shows a block diagram of the signal processing electronics 270 required to record both the single interaction events of the prior art and also the double interaction events of the present invention. The signals from the x-axis preamplifiers 40 and the y-axis preamplifiers 50 are processed by a timing and control block 275 . When the timing and control block 275 determines that the signals are coincident in time, with only one x and one y, i.e., a valid single pixel detection event, the corresponding strip numbers, (X, Y)=(i, k) are placed in the X l position register 280 and the Y l position register 300 . The energy signal from the i th x-axis preamplifier 40 is routed to the first x-axis shaping amplifier 281 and converted to a digital representation of the absorbed energy, E(X i ), by the first ADC 282 . The energy signal from the k th y-axis preamplifier 50 is routed to the first y-axis shaping amplifier 301 and converted to a digital representation of the absorbed energy, E(Y k ), by the first y-axis ADC 302 . The energy signals from the first set of x-axis and y-axis ADC's 282 , 302 will be essentially the same because the same charge signal in the detector 10 produced the signals. If the energy signals are within the energy window corresponding to the photon in use, the interaction is a valid non-scattered event and the image array processor 320 will increment the array memory location associated with the pixel (X, Y)=(i, k). Other than the availability of energy signals from both sides of the detector, this processing is essentially identical with prior art processing as in FIG. 2 .
When the timing and control block 275 determines that the signals from the x-axis preamplifiers 40 and the y-axis preamplifiers 50 are coincident in time, with two and only two values of X, X i and X j , and two and only two values of Y, Y k and Y l , the event is then flagged by the timing and control block 275 as a valid two pixel event. The X values are placed in the X 1 position register 280 and the X 2 position register 290 . The Y values are placed in the Y 1 position register 300 and the Y 2 position register 310 . The energy signals from the appropriate preamplifiers are routed to the shaping amplifiers 281 , 291 , 301 , 311 . The ADC's 282 , 292 , 302 , 312 produce digital representations of the energy signals of the four preamplifiers 40 , 50 .
The digital energy signals E(X i ), E(X j ) E(Y k ), and E(Y l ) are processed by the image array processor 320 to produce the valid pixel pair. When E(X i ) is equal to E(Y k ) and E(X j ) is equal to E(Y l ), the valid pair is (X, Y)=(i, k) and (X, Y)=(j, l). Next, the image array processor 320 determines if the interaction resulted in the absorption of the total energy of the target photon. The sum of E(X l ) and E(X j ) gives the total energy deposited in the detector 10 . When the total energy is within the energy window corresponding to the photon in use, the event is valid for forming the image. The image array processor 320 then determines the initial interaction point by selecting the smaller of E(X i ) and E(X j ). Because E(X i ) is the smaller energy, the pixel in array memory corresponding to location (X, Y)=(i, k) is incremented. In the simplified method memory locations corresponding to both pixels are incremented.
When the two pixels have identical X or Y values the logic is simpler. There is no ambiguity about the pixel selection. If the two pixels have the same X value the X 2 register 290 contains a zero. The single x-axis preamplifier 40 is routed to the first x-axis shaping amplifier 281 and the first x-axis ADC 282 . No signal is routed to the second x-axis shaping amplifier 291 so the second x-axis ADC 292 produces a zero result. If the image array processor 320 finds the sum of the energy values produced by the x-axis ADC's 282 , 292 to be within the energy window, the event is known to be a valid unscattered event. The smaller of the two y-energy values allows the selection of the preferred image producing pixel. The logic is similar if the two pixels have the same Y value.
Note that in the preceding descriptions of valid two interaction events, the energy values from the x-axis preamplifiers 40 were used by the image array processor 320 to assure that the total photon energy was absorbed by the detector 10 and that the correct first interaction point was selected. Those skilled in the art will recognize that the corresponding y-axis preamplifiers 50 produce the same signals and could be used to produce the same result. Consider the two energy signals E(X i ) and E(Y k ) in the preceding example. Because these signals are produced by the same charge carriers in pixel (i, k), they are essentially the same. However, because the noise contributions from the preamplifiers and other electronics are not exactly the same, the two values are not exactly equal. It may be advantageous to use the information from both sets of preamplifiers 40 , 50 to qualify the event. By averaging E(X l ) and E(Y k ), the precision of the energy determination is improved. Improving the precision of the energy measurements allows the energy window to be set to a smaller value and improves the rejection of photons scattered before they arrive at the detector 10 .
The flow chart of FIG. 6 is an alternative way of describing the logic of FIG. 5 . The acquisition of an image is started by the operator at step 340 . The program loops at step 350 waiting for a valid single pixel event producing an (X, Y) pair or a valid two pixel event producing two X values and two Y values. The two X values or the two Y values might be identical. At step 360 , one of two branches is taken depending on whether the event was a single pixel or a double pixel event. If only a single (X, Y) pair is found the program branches to step 370 where the energy is compared to the window. If the energy is not within the window the program branches back to the loop at step 350 . If the energy is within the window the memory array location corresponding to (X, Y) is incremented in step 380 and the program proceeds to step 430 . If a double pixel event is detected at step 360 the program proceeds to step 390 . In step 390 , if there are two distinct X values and two distinct Y values, a valid pair (X 1 , Y 1 ) and (X 2 , Y 2 ) is selected by noting that E(X 1 ) must equal E(Y 1 ) and that E(X 2 ) must equal E(Y 2 ). The total energy of the event is then determined in step 400 by adding E(X 1 ) plus E(X 2 ) or E(Y 1 ) plus E(Y 2 ) or by taking the average value of the two sums. If the total energy is not within the window the program moves back to the loop at step 350 . If the total energy is within the window the program moves to step 410 where the initial interaction pixel is selected by choosing the pixel pair in which the smallest energy is deposited. The program then moves to step 420 where the memory array location corresponding to the selected (X, Y) pair is incremented. In the simplified method memory locations corresponding to both pixels are incremented. Both steps 380 and 420 lead to step 430 . In step 430 a terminating condition is tested and, if met, the program proceeds to step 440 and stops. The terminating condition might be a preset time, a preset number of total counts, or an operator decision. If the terminating condition is not met the program returns to the loop at step 350 .
It will be obvious to those skilled in the art that a variety of alternate electronic circuits can produce the desired results of the present invention. In particular, the analog shaping amplifiers and ADC's of FIG. 5 could be replaced by sampling ADC's and digital filters.
While a preferred embodiment has been shown and described, it will be understood that it is not intended to limit the disclosure, but rather it is intended to cover all modifications and alternate methods falling within the spirit and the scope of the invention as defined in the appended claims.
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A method and apparatus for improving the sensitivity of a position sensitive gamma ray detector and gamma camera. To obtain good position resolution, small effective detector elements are required. However, such small detector elements cause nearly all the gamma rays interacting by Compton scattering to be lost, i.e., they will not contribute to forming the image. The method and apparatus of the present invention takes advantage of the fact that when an incoming gamma ray of known energy is completely absorbed in two separate detector elements the sum of the energy depositions identifies this gamma ray as a valid event. Furthermore, for incoming gamma rays having energies less than 511/2 keV the position where the smallest energy is deposited is the first interaction site and therefore this position can also contribute to forming the image. Alternatively, both interaction sites can be used to form the image, thus improving sensitivity but increasing background noise compared with the preferred embodiment.
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[0001] This invention relates to a power management method and system for a vehicle and particularly but not exclusively relates to a power management method and system for an aircraft.
BACKGROUND
[0002] Traditional power management in multi-engine applications, e.g. for an aircraft, may for example comprise a direct independent throttle engine power demand from a human operator (e.g. mechanical linkage from a throttle to a mechanical fuel metering device), or an independent engine Full Authority Digital Engine (or Electronics) Control (FADEC), which provides automatic fuel scheduling, limiting, monitoring and protection. This demand may correspond to a control parameter representing power (propulsive thrust) demand, for example, a spool speed or non-dimensionalised parameter such as a Turbofan Pressure Ratio (TPR) since this control parameter is strongly related to vehicle thrust, and is also influenced by environmental factors.
[0003] In some cases the individual demand from the pilot or system manager is augmented by a droop feedback loop. Droop feedback allows an offset from the pilot's demand by feeding back a change (e.g. a Delta) on the demand signal (typically as a function of how hard the engine is working) to prevent one engine taking more load than another. On some helicopters, this is augmented further still by sharing data on the relative difference in torque between engines to manage the load sharing.
[0004] Building on the above-mentioned systems, conceptual studies have looked at the impact of distributed power and thrust for single (multi-spool) engines, some of which have looked at using novel software techniques such as intelligent agents to manage this distribution. These studies were conducted in a modelled environment and the scope was typically engine-centric (i.e. it assumed a simple throttle/power demand input from the vehicle, from which the engine appropriated the best use of resources). This approach assumed a real-time approach to power distribution. However, these studies have met with limited success.
[0005] More recently, through the Autonomous Systems Technology Related Airborne Evaluation & Assessment (ASTRAEA) research program, the applicant of the present application explored concepts of centralised power control across multiple engines, and filed patent application GB2462180, which addressed vehicle-power system integration and optimisation. In the ASTRAEA concept, the vehicle understood the limits of power it could tolerate for a particular mission leg. This information was then passed to the power system to plan and decide where and how to deliver this in a power-optimised way, whilst accounting for system health and the (time-varying) limits allocated by the vehicle.
[0006] There are a number of other proposals which aim to take this further. For example, centralised management of power generation and loads at a vehicle level have been considered. Notably, WO2010/047902 describes a system which is aware of its mission in advance and is able to plan the optimum scheduling and usage of its loads and power generation and storage devices. An outline of this approach is depicted in FIG. 1 in which an energy manager 10 communicates with first and second intelligent loads 20 , 30 , a dumb load 40 , a generator 50 and a supplementary power source 60 . The energy manger 10 receives mission data and based on the mission data distributes the power resources to the loads 20 , 30 , 40 in an optimal manner.
[0007] However, the applicant is not aware of a power system which will deliver an holistic power management solution for an autonomous vehicle. (By way of example, an holistic power management system in the case of an aircraft would consider propulsion, electrical load-capacity balance, scheduling of events or routes to optimise energy usage and take account of external influences such as prevailing conditions or terrain.) For example, whilst some concepts focus on the low-level administration of power (in some cases attempting to use novel software techniques), they do not address the whole power management problem for the entire vehicle. Some concepts manage the overall administration of power generation, but focus on one aspect alone (e.g. thrust as disclosed in GB2462180 or electrical load/storage alone as in WO2010/047902).
[0008] In addition to the above, other previous concepts assume a vehicle-centralised approach to power management, which would require a single system having total domain knowledge of all of the constituent elements (i.e. across power plant provider, airframe, and airframe sub-systems providers in the case of an aircraft). However, this is unlikely to be acceptable for each of the respective manufacturers since they will be reluctant to share their proprietary information, e.g. detailed performance data. Furthermore, such an approach does not facilitate adaptation to different platforms or subsystems.
[0009] Where attempts have been made to develop architectures which do consider the holistic power challenge, such systems have inherent conflicts. For example, a subsystem optimising for a best-route may wish to extend a mission leg to accommodate a circumnavigation of a hill, whereas an environment-load optimising sub-system may wish to reduce the same mission leg to avoid struggling into a prevailing headwind. To date such tensions in an intelligent power management system may only be resolved by holistic domain knowledge, but this requires knowledge of proprietary information, which, as mentioned above, is unlikely to be forthcoming.
[0010] The present disclosure therefore seeks to address the aforementioned issues.
STATEMENTS OF INVENTION
[0011] According to a first aspect of the present invention there is provided a method of managing energy and/or power in a vehicle, the vehicle comprising: one or more vehicle power systems adapted to control one or more power consuming components of the vehicle and one or more power producing components of the vehicle; and one or more propulsive power systems adapted to control one or more propulsive power units of the vehicle, wherein the method comprises:
(i) proposing a vehicle route for a predetermined mission and/or destination; (ii) determining a time-based operational plan for each of the vehicle power consuming components, e.g. based on the requirements of the proposed vehicle route or mission; (iii) determining the power required by the vehicle power consuming components and the propulsive power required by the vehicle as a function of time during the operational plan; (iv) determining the power required from the vehicle power producing components and the propulsive power required by the propulsive power units as a function of time during the operational plan; and (v) varying the proposed vehicle route and/or the operational plan and repeating at least steps (iii) to (iv) to optimise a predetermined performance criterion for the vehicle.
[0017] The steps (i) to (v) may or may not be carried out one after the other, for example, there may be some degree of overlap between the steps, or they may be carried out in a different order to that described above.
[0018] The method may further comprise dividing the operational plan into one or more time phases. Each phase may represent a particular mode of operation for the vehicle. For example, in the case of the vehicle being an aircraft, one or more of the time phases may correspond to taxiing, taking-off, climbing, cruising, descending, landing, taxiing, idling and/or refuelling. The operational plan may be divided into one or more phases prior to proposing the vehicle route. The method may further comprise varying the duration of one or more of the time phases to optimise the predetermined performance criterion.
[0019] The mission and/or destination may comprise one or more defined route waypoints.
[0020] One or more of the vehicle power systems and/or propulsive power systems may suggest one or more variations to the operational plan in order to further optimise the predetermined performance criterion. The method may subsequently comprise determining whether to adopt one or more of the suggested variations to the operational plan; and varying the operational plan according to one or more of the suggestions from the systems to further optimise the predetermined criterion. The dependency between the other vehicle power systems and/or propulsive power systems may be taken into account. The suggested variations to the operational plan may comprise suggested variations to the duration of one or more of the time phases. For example, by extending a cruise phase by 20 minutes it may be possible for an alternative power producing component to be fully charged, which may enable use of this power producing component to provide power in addition to a primary power source, e.g. to serve planned large transient power demands in the next mission phase.
[0021] The vehicle route may be varied independently of varying the scheduled use of the one or more of the propulsive power systems to optimise the predetermined performance criterion for the vehicle. The method may further comprise varying the scheduled use of one or more of the vehicle power systems within the operational plan independently of varying the scheduled use of the one or more of the propulsive power systems to optimise the predetermined performance criterion for the vehicle. For example, in an aircraft system with two gas turbine propulsive power units, electrical vehicle power producing components and electrical vehicle power consuming components, the method may vary the planned route, as well as independently considering variation of the thrust produced by each gas turbine, in addition to independently considering varying the schedule for electrical power generation, or consumption by the power consuming components. Any combination of these variations may be considered, but all variations aim to optimise the performance based criteria, such as fuel consumption.
[0022] The method may further comprise varying the scheduled use of one or more of the propulsive power systems within the operational plan independently of varying the scheduled use of the one or more of the vehicle power systems to optimise the predetermined performance criterion for the vehicle. For example, a system with two gas turbine propulsive power units, electrical vehicle power producing components and electrical vehicle power consuming components, the method may determine to increase propulsive power of one gas turbine and reduce power from the other gas turbine to optimise the fuel burn performance criterion, based on a suggestion by the propulsive power system.
[0023] One or more power sensors may be queried to determine the vehicle power system and/or propulsive power system power levels. The power sensors may be configured to sense the energy and/or power being consumed or produced by components controlled by the vehicle power system and/or propulsive power system, e.g. by measuring voltages, currents, speeds, torques etc. The power levels, e.g. individual or total power levels, may be accounted for when determining the power required from the vehicle power producing components and/or the propulsive power required from the propulsive power unit as a function of time during the operational plan.
[0024] One or more health sensors may be queried to determine the vehicle health, vehicle power system health, power consuming component health, power producing component health, propulsive power system health and/or propulsive power unit health. The health may be accounted for when determining the power required from the vehicle power producing components and/or the propulsive power required from the propulsive power unit as a function of time during the operational plan.
[0025] Any of the aforementioned method steps may be carried out whilst the vehicle undergoes the vehicle route. The vehicle route and/or operational plan may be refined, e.g. dynamically, to optimise the predetermined performance criterion for the vehicle, for example, in response to a change in the mission and/or destination during the vehicle route. As a result, the present invention may work with a number of time horizons, for example the present invention may adapt a long term plan to take account of real-time demands.
[0026] The method may further comprise predetermining an optimal vehicle route and operational plan prior to commencing the vehicle route. For example, the predetermined optimal route and operational plan may be used as a starting point in steps (i) and (ii) above.
[0027] The predetermined performance criterion may be one of energy efficiency, emissions output, vehicle route completion time, persistence of the vehicle, e.g. in the air, or the operational life of the vehicle and/or one or more of the vehicle components or any other performance criterion.
[0028] The power consuming components may consume one or more of electrical power, mechanical power, hydraulic power, pneumatic power, propulsive power or any other type of power or combination thereof. The power consuming components may comprise one or more of electrical systems, air conditioning, cabin heaters, cooking heaters, radar guidance systems, cameras, vehicle weapons systems, vehicle defence systems, communications systems, entertainment systems, anti-icing heaters, sensors, hydraulic actuators, pneumatic actuators, electrical actuators, pumps, lighting, aerofoil surfaces, drag inducing surfaces or any other power consuming component.
[0029] The power producing components may comprise one or more of an electrical generator, a gas turbine engine, a diesel engine, a solar cell, a wind turbine, a nuclear reactor, a fuel cell, a thermo-electric generator or any other power producing component, e.g. which may provide the means of converting energy.
[0030] The propulsive power unit may comprise one or more of a gas turbine engine, a diesel engine (e.g. coupled to a propulsive drive), a turbine (e.g. steam), a motor, sail, or any other source of propulsion.
[0031] The vehicle may further comprise energy storage means. The energy storage means may store electrical, mechanical and/or hydraulic energy. For example, the energy storage means may comprise one or more of a battery, a capacitor, a flywheel, an hydraulic accumulator or any other energy storage device. The energy storage means may be accounted for when determining the power required from the vehicle power producing components and the propulsive power required by the propulsive power unit as a function of time during the operational plan.
[0032] The vehicle may be an aircraft (civil or military), a marine vessel (e.g. ship or submarine), land-based vehicle (e.g. a car) or any other type of vehicle. The vehicle may be autonomous, e.g. the vehicle may be unmanned or it may have an auto-pilot.
[0033] According to a second aspect of the present invention there is provided a system and/or controller, e.g. a central controller, adapted to carry out any combination of the aforementioned methods. For example, such a controller or system may oversee all of the vehicle's energy and/or power planning. A vehicle may comprise such a controller or system.
[0034] The present disclosure offers mission level energy and power management technology, primarily, although not exclusively, for autonomous vehicles. The methods and systems disclosed herein may rely on a knowledge of vehicle environmental factors, intended vehicle route, mission plan, power system configuration and power system health to achieve its benefits. Based on this knowledge, a prediction of required vehicle energy requirements and a consequent planned mission energy supply are derived. The planned energy supply is optimised against a customer (vehicle) criteria (or cost function). The technology may offer dynamic in-mission re-planning in response to a change in any of the environment factors listed or change in the mission plan, vehicle route or power system health.
[0035] The present disclosure improves upon the previously-proposed autonomous power management systems (e.g. GB2462180) by iteratively interacting with the whole vehicle's systems and converging on a compromise. In doing so, the present disclosure enables improved optimisation where previously the power system optimisation was constrained to the power system's domain.
[0036] The present disclosure may advantageously provide a means to exploit previously inaccessible optimisation of vehicle power, without requiring the transfer of confidential performance data for the vehicle and/or subsystems. A scalable, flexible interface which supports any vehicle platform architecture, from simple throttle demand, all the way up to power profile and feedback-advisory for convergent optimisation may also be provided.
[0037] Furthermore, the present disclosure considers the holistic power domain (for example, all energy and/or power loads, the propulsive demand, electrical, hydraulic, pneumatic, health/parasitic losses, energy scavenging and harvesting, adverse or beneficial environmental factors and route) and optimises the plan based on an initial mission, but may dynamically respond with an updated plan as the situation (e.g. health, environment) and/or mission evolve.
[0038] The methods and systems disclosed herein may also automatically reconfigure the operational plan in response to changes to the load or sensor subsystems (e.g. as a result of maintenance) to provide energy supply re-planning during a vehicle journey. The ability to automatically reconfigure and re-plan the power supply accordingly offers enhanced flexibility. The energy supply planning may also take account of the particular characteristics of each power source (e.g. start up time and profile, shutdown needs) and power sink (electrical load profile against time, required power supply quality etc.).
[0039] Further advantages include reduced operating cost and reduced risk. For example, an optimised power supply may reduce fuel consumption and/or reduce maintenance cost (e.g. via better health management of power system components). Furthermore, the ability to autonomously manage occurrences in mission, changes to environmental conditions and changes to the mission plan reduces the chance of mission aborts and minimises risk.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:
[0041] FIG. 1 shows a prior art power management system;
[0042] FIG. 2 is a contextual diagram showing the Intelligent Power Manager (IPM) in its environment;
[0043] FIG. 3 is an architectural schematic diagram of the IPM; and
[0044] FIG. 4 outlines an iterative sequence for the IPM.
DETAILED DESCRIPTION
[0045] The present disclosure relates to a method comprising concurrent processing and arbitration to optimise power consumption in a vehicle. More specifically, the present disclosure may relate to an iterative convergence on an optimal solution and may use a common language across sub-system boundaries. Accordingly a system architecture and method are disclosed herein.
[0046] The present disclosure may relate to a hierarchical architecture for an autonomous vehicle and its subsystems (e.g. as shown in FIG. 2 ). One of the proposed subsystems on such a vehicle is the Intelligent Power Manager (IPM) 101 , which is responsible for the planning, scheduling and control of all of the power sources and sinks on the vehicle. It is the IPM functionality and its interactions with the wider vehicle architecture that are the subject of this invention.
[0047] With reference to FIG. 2 , a conceptual representation of the IPM system 101 within its environment is shown. The key inputs and outputs are identified. For example, the IPM 101 receives data from: a vehicle 105 (e.g. vehicle health, fuel levels, air speed, altitude etc.), the environment 106 (e.g. terrain, meteorological data), the route planner 104 (specified waypoints, tolerances, etc.) and from the power system 102 (health and status data).
[0048] Furthermore, the IPM 101 interacts with the Mission Executive (ME) 103 , which is the highest level of decision making authority within the vehicle system. The ME 103 provides information on the nature of the current mission such as specific mission phases, their duration and tolerance, which sensors or payloads to deploy and when, and the preferred characteristic against which to optimise, etc. Finally, the IPM 101 may also interact with a user 107 , for example to receive system architecture information, such as in the case where certain vehicle mission systems are configurable to suit the particular mission, or manual demand or override instructions. Status information may also be transmitted to the user 107 .
[0049] The IPM 101 combines all of the incoming data together to generate a planned course of action to best deploy the available power sources and sinks, which it outputs as an advisory to the ME 103 and as a demand upon the various power sub-systems 102 . Accordingly, the key functions to be performed by the IPM 101 are: to predict the power demand; plan and optimise the power supply; control the power systems; manage the power system health (including contingency management); and manage communication and data.
[0050] With reference to FIG. 3 , an architectural schematic of the IPM 101 is shown. As depicted, the IPM 101 may comprise two separate components: a vehicle-domain comprising a Power Management System (PMS) 101 a ; and a power system domain comprising an Intelligent Adaptive Power System Manager (IAPSM) 101 b . The PMS 101 a predicts the power demand from the vehicle, whilst the IAPSM 101 b plans the power supply to the vehicle to meet the power demand. The IAPSM 101 b may also manage the power systems health, manage data and communications and control the power systems, for example through a low level power control such as a FADEC 108 . The power systems may comprise power consuming systems and not just power producing systems.
[0051] A key architectural feature of the PMS 101 a is that the “Predict Power Demand” function resides within the vehicle provider's scope of supply, whilst the remaining functions of the IAPSM 101 b reside within the power system provider's scope of supply. The reason for this separation is that the data the PMS and IAPSM require is domain specific and subject to the respective system provider's Intellectual Property. For example, the derivation of a power demand from route data will require use of the proprietary vehicle performance data (drag coefficients, performance characteristics etc.). Likewise, calculation of a power system's projected capability to generate power will also depend on proprietary design data. Thus the IPM 101 functionality may reside in separate parts in order to maintain the domain specific Intellectual Property Rights (although physically these aspects may be co-located).
[0052] A further advantage of the split functional architecture described above is that it is scalable, for example to support a wide variety of potential applications of the IAPSM (and hence Power system provider's scope of supply) with minimal change. In its simplest form, the IAPSM may receive conventional demands (throttle, electrical load requests) and may be able to do some internal optimisation to allocate the demands amongst the sources and sinks to provide the most optimal solution (e.g. most fuel-efficient or greatest persistence). However, with minimal change, the architecture and interfaces described herein may permit the IAPSM to support any variation of application, up to and including an intelligent autonomous system incorporating full mission awareness, future power demand prediction, planning and dynamic re-optimisation in response to changing circumstances.
[0053] With reference to FIG. 4 , the functions 201 to 211 performed within the IPM 101 are depicted. As shown the functions may be carried out in an iterative sequence. Functions 201 to 205 may be carried out by the PMS 101 a and these functions may predict the power demand. Functions 206 to 210 may be carried out within the IAPSM 101 b side of the IPM 101 and these functions may deliver aspects of the remaining IPM functionality. However, it is to be noted that some aspects of these IPM functions may be executed outside of the IPM 101 . For example, the low-level execution of the control power system 108 may be performed by a traditional FADEC, which takes its demands from the IAPSM, and the mission route may be derived in function 203 with the assistance of the route planner 104 . The functions are described in more detail below.
[0054] Function 201 derives a common time-base as a reference for all of the remaining functions. The time-base defines the mission phases against time for a particular iteration of the planning and optimisation sequence. In the case of the vehicle being an aircraft, the time-base mission phases may comprise taxiing, taking-off, climbing, cruising, descending, landing, taxiing, idling and/or refuelling. Function 201 assigns a time duration to each of these phases. The durations for each phase (and hence the relative times for a given time-base) will be within the tolerances set by the ME 103 . For example, the ME 103 may stipulate a limit on the duration of the take-off phase. The time-base may be changed in subsequent iterations. Varying these relative mission phase times (within the tolerances) gives one degree of freedom common to all functions within the sequence with which collective optimisation may be achieved.
[0055] After the common time-base has been established, function 202 may derive the vehicle health. Function 202 may use instantaneous and/or extrapolated health data relating to the vehicle to estimate the impact on energy consumption. For example, function 202 may identify a fuel leak in the fuel tanks or a slow retracting flap actuator, both of which will adversely affect fuel consumption. The health data may be derived outside the IPM 101 . Function 202 generates a profile of energy drain against the time-base.
[0056] In parallel to function 202 , function 203 may derive the mission route for the vehicle. (Function 203 may alternatively be carried out after or before function 202 .) In deriving the vehicle route, function 203 may query the route planner 104 , which may be external to the IPM 101 . For a given performance criterion (e.g. energy efficiency, emissions output, completion time, persistence or operational life), function 203 may attempt to optimise a route using waypoints and the permitted tolerances provided by the ME 103 . In other words, function 203 may carry out some local optimisation with the given waypoints, time-base, permitted tolerances and performance criterion against which to optimise. For example, the proposed optimal route will differ depending on whether the performance criterion is earliest arrival time or minimum energy usage (over the hill versus divert around it). There may be some degrees of freedom within which function 203 may optimise, for example a permitted deviation radius from a mandated waypoint. By contrast, there may be constraints on the optimisation within function 203 , one of which will be the time per phase, including associated time tolerances on phase duration, from the mission time-base. The output from function 203 is a detailed route and a propulsive energy load profile against the mission time-base.
[0057] The energy load profile obtained from function 203 may be in non-dimensional terms and environmental data such as humidity, temperature and pressure may be required in order to express the load profile in dimensional terms. Thus, following function 203 , function 204 may derive the mission environment and in doing so may analyse the terrain, tide, meteorological data etc. for the derived route and time-base, to estimate the impact on energy consumption. Function 204 generates a profile of energy drain against the time-base, based on the proposed mission route of function 203 . Function 204 may also carry out some optimisation of the performance criterion by varying the vehicle route and/or time-base. For example, function 204 may request a different vehicle route, e.g. to avoid a thunderstorm or simply to avoid a region with high humidity and hence higher drag.
[0058] Function 205 sums the load profile from functions 203 and 204 and takes account of the energy drains from function 202 . In an alternative arrangement, function 205 may also include in its summation the sensor and actuator load profiles derived by function 208 (function 208 is described in more detail below). Accordingly, function 205 builds a summary of the energy demand against the time-base and this energy demand may be subsequently used by the IAPSM 101 b . Function 205 may also carry out some optimisation of the performance criterion by varying the vehicle route and/or time-base. For example, function 205 may instruct function 201 to change the time-base (denoted by feedback path A), e.g. to delay descent to avoid clouds or prolong the climb phase to reduce power required.
[0059] Having established the load profile for the vehicle in the PMS 101 a , the time-base and load profile are sent to the power system domain, e.g. the IAPSM 101 b . Within the IAPSM 101 b function 206 derives the power system health. To estimate the impact on energy consumption and energy transformation, function 206 may use instantaneous and/or extrapolated health data relating to the power systems such as generator windings, gas turbine rotating parts, batteries, sensor payloads (e.g. cameras, radar etc.). (Such health data may be derived outside the IPM 101 .) In a manner similar to function 202 for the vehicle, function 206 generates a profile of the energy drain against the time-base for the power systems.
[0060] In parallel to or after function 206 , function 207 derives the power system status. Function 207 evaluates the current levels of energy on board the vehicle in all of their forms and assesses the rate at which energy is being converted (e.g. both in terms of consumption and production rates). The energy evaluated by function 207 comprises propulsive thrust as well as other forms of energy required on board the vehicle. The power system status derived by function 207 is used to build a plan for the vehicle. The power system information is also used to compare the planned system behaviour against the actual behaviour. Any discrepancies arising from this comparison may be used to dynamically reconfigure and adapt the models, such that the plans for the vehicle continuously evolve or reconfigure to reflect reality.
[0061] Again, in parallel to or after functions 206 or 207 , function 208 derives sensor and/or actuator load profiles. Function 208 uses the demand data for specific sensors and/or actuators during the mission phases in which they are required and their known characteristics to build a profile of expected energy demand against the mission time-base. The characteristics for the sensors and/or actuators are available to function 208 and may be stored locally, e.g. in the IPM 101 , on the sensors and/or actuators or elsewhere on the vehicle. For example, the characteristics (e.g. start-up, shutdown, power draw profile) for each source and sink device may be stored in library files, which the system may be configured with pre-mission or the system may even automatically recognise each device as-fitted. In an alternative arrangement, function 208 may reside within the PMS 101 a (i.e. vehicle scope of supply). Equally, aspects of function 208 may be carried out by both the PMS 101 a and the IAPSM 101 b , for example, aileron actuators may be accounted for within the PMS 101 a and engine reverse thrust actuators may be accounted for in the IAPSM 101 b.
[0062] Function 208 may also locally optimise within provided tolerances in order to avoid coincident demands for sensors and/or actuators where possible, for example to minimise load-peaks. For example, a satellite communication or navigation device may be scheduled to be activated at a particular time which would clash with the use of a ground-scanning radar. Function 208 may reschedule the satellite activation to avoid occurring at the same time as the radar use. The intensity of the sensors and/or actuators may also be varied by function 208 , e.g. within a given tolerance. By way of example a de-icing system may run at maximum power for a demanded period, but it may be permissible to run the de-icing system at part-power for a longer period, which minimises the peak demand on the system.
[0063] After functions 206 , 207 and 208 , function 209 plans the power supply. Function 209 collates the summed load profile from functions 205 and 208 , the power system health from function 206 and the power system status from function 207 , and derives the best plan it can to optimise the performance criterion given the time-base. For example, function 209 may apportion generation and load such that each device is operating within its peak efficiency band, it may identify a need to proactively store excess generating capacity to address a short-term peak or it may even require the system to scavenge energy which was not previously on board the vehicle, e.g. by refuelling.
[0064] Once the power supply has been initially planned by function 209 , function 210 may select or further optimise the plan. Accordingly, function 210 either selects and passes on a viable plan to control the power systems or provides an opportunity for optimisation, e.g. by varying the time-base via feedback path B.
[0065] However, whilst each of the aforementioned functions may perform as much local optimisation as it can, further optimisation of a particular function may conflict with the goals of other functions. By way of example, function 202 may identify that energy may be saved by reducing a loiter period (say mission phase 4 ) by four hours, to reduce the fuel lost by a leak it has identified. However, function 203 may have decided that in order to minimise energy consumption, it should plot a diversion around a mountain range, thus extending mission phase 4 by another hour. The extension of this phase by an hour would lead to encountering adverse weather and headwinds, as identified by function 204 , which wants to reduce the mission by an hour to avoid this. Meanwhile function 209 may have identified the need to scavenge for an energy shortfall, which requires a five hour stop to replenish energy reserves. Thus, it can be seen that many conflicts or tensions may exist within the system.
[0066] One way to perform optimisation across sub-systems in tension like this would be to permit concurrent arbitration and negotiation between them, with each function operating as an agent with its own goals and the system having a collective aim to reach the optimum compromise. However, such systems are likely to be very calculation intensive and, as their behaviour is not possible to predict, they remain a significant challenge to certification, at least for air vehicles. Additionally to perform optimisation concurrently across all subsystems may require significant transfer of proprietary data, which may be viewed as undesirable by the subsystem developers. Nevertheless, an off-board implementation of such an arbitration system (hence without the constraints of flight-certification or processing time) could be utilised as a pre-mission optimisation, which could provide a pre-optimised plan to the vehicle as a starting point.
[0067] However, to enable on-board optimisation, an alternative optimisation approach may be considered. For example, each of the aforementioned functions in the process may generate both its output (as described already) and an optimisation pointer. The optimisation pointer may comprise a measure of the benefit to be had if a suggested course of action is taken. The optimisation pointers provided by each function may be in a common form or language. By way of an example, such a pointer could be in the form of: “Could save 10 kWh if extend mission phase 5 by two hours; Reason: circumnavigate adverse terrain”. Such optimisation pointers may be rendered in numerical advisories which can be quickly evaluated against each other (by function 210 ) to pick the best and/or easiest course of action to achieve some optimisation. The enabler for such an optimisation is a common parameter, which in this case is time or, more specifically, the time for each phase in the time-base.
[0068] Based upon the optimisation pointers it receives from the preceding functions, function 210 may identify and request a change to the time-base (via feedback path B in FIG. 4 ) which potentially gives the largest benefit to the performance criterion. Once the sequence of functions has been re-run the outcome may be assessed. Such an iteration may be expected to deliver some improvement and, if so, the improved new plan and its corresponding time-base may be stored. However, there is a chance that such an iteration may have a negative effect on the performance criterion. If this is the case, an alternative optimisation pointer may be pursued, until an optimal solution is converged upon. The optimisation cycle may be halted, e.g. after a certain amount of time, number of iterations or once no further improvements can be found. The best available plan at that point may then be selected by function 210 .
[0069] This alternative optimisation approach using optimisation pointers is less computationally intensive than using negotiating agents and may therefore be carried out during the vehicle's route. The use of optimisation pointers also avoids the aforementioned Intellectual Property Rights conflicts between the vehicle and power systems providers, since the providers may be more willing to provide optimisation pointers as opposed to full performance data.
[0070] Following function 210 , function 211 controls the power systems. Function 211 takes the selected power plan for all of the power systems, and combines it with the immediate demand from the vehicle. In this way, the IPM 101 can provide power to address the immediate demand from the vehicle, whilst provisioning extra margin for expected transients or peaks or the need to store spare capacity to discharge later. The power system control applies to all aspects of power generation and consumption and as such applies to prime movers (e.g. internal combustion engines, gas turbines etc.), generation sources (e.g. fuel cells, solar panels etc.), energy storage (e.g. batteries, super-capacitors etc.) and the loads (e.g. electrical, thrust, hydraulic, etc.).
[0071] The individual demands from function 211 are passed on to low level controllers 108 outside the IPM 101 . The demands may be in the form of a simple switch demand or a more complex demand comprising a parameter demand and sequencing to a controller of a complex machine (e.g. a FADEC for a gas turbine). It is at this stage that a more reactive control may take place, i.e. for occurrences which require a medium to rapid response. For example, a high criticality event, such as a shaft over-speed will be controlled within a very fast timeframe (i.e. milliseconds) by the FADEC or another independent system. By contrast, a failure of a gas turbine (e.g. flameout) must be accommodated in a medium to fast timeframe (i.e. seconds). This might involve taking up the load from the failed gas turbine with other available stored energy devices, while bringing another generator online. The same event would provoke a still-longer timeframe response (say in a matter minutes) in which the above-mentioned power planning loop begins optimising, and within an acceptable period generates a planned response in function 210 , which subsequently supersedes the reactive one enacted in function 211 .
[0072] The systems and methods described herein may be part of an integrated power management system, which may for example manage power generation and distribution amongst the available assets according to their individual health status and demands. The present disclosure is generic in nature and so may be readily applied to other autonomous (e.g. unmanned) applications. For example, the methods and systems described herein may also be applied to ship power generation optimisation, where there can be different sources of power, often multiple diesel and/or gas-turbine engines, which have different characteristics for optimal performance. The technology could be used to optimise in real-time to give best fuel performance, or best engine life, depending on the cost function applied. The present disclosure may also be applied to autonomous land vehicles and autonomous underwater vehicles.
[0073] In addition to autonomous systems, the present methods and systems may also be suitable for manned systems, where the technology offers reduced operator workload through management of tasks currently performed or supervised by pilots or operators. The pilot or operator workload may thus be reduced, thereby minimising the risk of error from overloaded operators, or reducing the manning requirements on a whole-system.
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A method of managing energy and/or power in a vehicle, including: one or more vehicle power systems adapted to control one or more power consuming components of the vehicle and one or more power producing components of the vehicle; and one or more propulsive power systems adapted to control a propulsive power unit of the vehicle. The method includes: proposing a vehicle route for a predetermined mission and/or destination; determining a time-based operational plan for each of the vehicle power consuming components; determining the power required by the vehicle power consuming components and the propulsive power required by the vehicle; determining the power required from the vehicle power producing components and the propulsive power required by the propulsive power unit as a function of time during the operational plan; and varying the proposed vehicle route and/or the operational plan to optimize a predetermined performance criterion for the vehicle.
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BACKGROUND
[0001] This application relates to accessory air flow for use on an aircraft.
[0002] Gas turbine engines typically need a good deal of accessory air. Air is utilized for various purposes such as cooling components on the engine. Also, gas turbine engines utilized on the aircraft also supply air for use in the cabin of the aircraft. All of these applications require relatively high volumes of air.
[0003] Historically, a fan drove air into the gas turbine engine. This fan has typically been driven at the same speed as a lower pressure compressor which is downstream of the fan. More recently, a gear reduction has been incorporated between the fan and the low pressure compressor, and in such engines, the fan rotates at a slower speed compared to the low pressure compressor. With such engines, the air available for accessory use is moving at a slower speed than in the past, and there may not be sufficient volume as would be desirable.
SUMMARY
[0004] In a featured embodiment, a gas turbine engine has a first source of air to be delivered into a core of the engine, and a second source of air, distinct from the first source of air and including separately controlled first and second fans, each delivering air into respective first and second conduits connected to distinct auxiliary applications.
[0005] In another embodiment according to the previous embodiment, the first and second fans are positioned to be downstream of a heat exchanger.
[0006] In another embodiment according to any of the previous embodiments, the heat exchanger is an air to oil cooler.
[0007] In another embodiment according to any of the previous embodiments, one of the applications is for cooling a pitch control mechanism for a propeller included in the gas turbine engine.
[0008] In another embodiment according to any of the previous embodiments, at least one of the applications is for cooling a gear reduction incorporated into the gas turbine engine to drive a propulsor.
[0009] In another embodiment according to any of the previous embodiments, the air to oil cooler receives oil which is utilized to cool the gear reduction for driving the propulsor.
[0010] In another embodiment according to any of the previous embodiments, the first and second fans may be caused to deliver distinct amounts of air to first and second conduits each leading to one of the distinct auxiliary locations.
[0011] In another embodiment according to any of the previous embodiments, at least one of the applications is for an environmental control system.
[0012] In another embodiment according to any of the previous embodiments, at least one of the applications is for an environmental control system.
[0013] In another embodiment according to any of the previous embodiments, the first and second fans are separately controlled such that they may be caused to deliver distinct amounts of air into the first and second conduits.
[0014] In another embodiment according to any of the previous embodiments, at least one of the applications is for cooling a gear reduction incorporated into the gas turbine engine to drive a propulsor.
[0015] In another embodiment according to any of the previous embodiments, one of the applications is for cooling a pitch control mechanism for a propeller included in the gas turbine engine.
[0016] In another embodiment according to any of the previous embodiments, a propulsor is provided in the gas turbine engine.
[0017] In another embodiment according to any of the previous embodiments, the propulsor is driven by a propulsor turbine through a propulsor drive shaft that is downstream of a turbine section driving a compressor section.
[0018] In another embodiment according to any of the previous embodiments, the propulsor turbine drives a fan at an upstream end of the engine.
[0019] In another embodiment according to any of the previous embodiments, the turbine section includes a first and second turbine rotor. The compressor section includes a first and second compressor rotor. The first turbine rotor drives the first compressor rotor, and the second turbine rotor drives the second compressor rotor.
[0020] In another embodiment according to any of the previous embodiments, an axially outer position is defined by the fan. The propulsor turbine is positioned between the fan and the first and second turbine rotors. The first and second compressor rotors are positioned further into the engine relative to the first and second turbine rotors.
[0021] In another embodiment according to any of the previous embodiments, the propulsor is at least one propeller.
[0022] In another embodiment according to any of the previous embodiments, the first turbine rotor drives the first compressor rotor through a first shaft and the second turbine rotor drives the second compressor rotor through a second shaft. The first shaft surrounds the second shaft. The propulsor drive shaft is spaced axially further into the engine relative to the first and second shafts.
[0023] In another embodiment according to any of the previous embodiments, the propulsor is a propeller.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 schematically shows a three spool gas turbine engine.
[0025] FIG. 2A shows a second embodiment.
[0026] FIG. 2B shows another embodiment.
[0027] FIG. 3 shows a first embodiment air supply system.
[0028] FIG. 4 shows a second embodiment.
[0029] FIG. 5 shows a schematic system.
DETAILED DESCRIPTION
[0030] A gas turbine engine 19 is schematically illustrated in FIG. 1 . A core engine, or gas generator 20 , includes high speed shaft 21 is part of a high speed spool along with a high pressure turbine rotor 28 and a high pressure compressor rotor 26 . A combustion section 24 is positioned intermediate the high pressure compressor rotor 26 and the high pressure turbine rotor 28 . A shaft 22 of a low pressure spool connects a low pressure compressor rotor 30 to a low pressure turbine rotor 32 .
[0031] Engine 19 also includes a free turbine 34 is shown positioned downstream of the low pressure turbine rotor 32 and serves to drive a propeller 36 .
[0032] Various embodiments are within the scope of the disclosed engine. These include embodiments in which:
[0033] a good deal more work is down by the low pressure compressor rotor 30 than is done by the high pressure compressor rotor 26 ;
[0034] the combination of the low pressure compressor rotor 30 and high pressure compressor rotor 26 provides an overall pressure ratio equal to or above about 30;
[0035] the low pressure compressor rotor 30 includes eight stages and has a pressure ratio at cruise conditions of 14.5;
[0036] the high pressure compressor rotor 26 had six stages and an overall pressure ratio of 3.6 at cruise;
[0037] a ratio of the low pressure compressor pressure ratio to the high pressure compressor ratio is greater than or equal to about 2.0, and less than or equal to about 8.0;
[0038] more narrowly, the ratio of the two pressure ratios is between or equal to about 3.0 and less than or equal to about 8;
[0039] even more narrowly, the ratio of the two pressure ratios is greater than about 3.5.
[0040] In the above embodiments, the high pressure compressor rotor 26 will rotate at slower speeds than in the prior art. If the pressure ratio through the fan and low pressure compressor are not modified, this could result in a somewhat reduced overall pressure ratio. The mechanical requirements for the high pressure spool, in any event, are relaxed.
[0041] With the lower compressor, the high pressure turbine rotor 28 may include a single stage. In addition, the low pressure turbine rotor 32 may include two stages.
[0042] By moving more of the work to the low pressure compressor rotor 30 , there is less work being done at the high pressure compressor rotor 26 . In addition, the temperature at the exit of the high pressure compressor rotor 26 may be higher than is the case in the prior art, without undue challenges in maintaining the operation.
[0043] A bleed line or port 40 is positioned between the low pressure compressor rotor 30 and the high pressure compressor rotor 26 . Details of this porting are disclosed below.
[0044] Variable vanes are less necessary for the high pressure compressor rotor 26 since it is doing less work. Moreover, the overall core size of the combined compressor rotors 30 and 26 is reduced compared to the prior art.
[0045] The engine 60 as shown in FIG. 2A includes a two spool core engine 120 including a low pressure compressor rotor 30 , a low pressure turbine rotor 32 , a high pressure compressor rotor 26 , and a high pressure turbine rotor 28 , and a combustor 24 as in the prior embodiments. This core engine 120 is a so called “reverse flow” engine meaning that the compressor 30 / 26 is spaced further into the engine than is the turbine 28 / 32 . Air downstream of the fan rotor 62 passes into a bypass duct 64 , and toward an exit 65 . However, a core inlet duct 66 catches a portion of this air and turns it to the low pressure compressor 30 . The air is compressed in the compressor rotors 30 and 26 , combusted in a combustor 24 , and products of this combustion pass downstream over the turbine rotors 28 and 32 . The products of combustion downstream of the turbine rotor 32 pass over a fan drive turbine 74 . Then, the products of combustion exit through an exit duct 76 back into the bypass duct 64 (downstream of inlet 66 such that hot gas is not re-ingested into the core inlet 65 ), and toward the exit 65 . A gear reduction 63 may be placed between the fan drive turbine 74 and fan 62 .
[0046] The core engine 120 , as utilized in the engine 60 , may have characteristics similar to those described above with regard to the core engine 20 .
[0047] The engines 19 and 60 are similar in that they have what may be called a propulsor turbine ( 34 or 74 ) which is spaced to be axially downstream of the low pressure turbine rotor 32 . Further, the high pressure spool radially surrounds the low pressure spool, but neither of the spools surround the propulsor turbine, nor the shaft 100 connecting the propulsor turbine to the propellers 36 or fan 62 . In this sense, the propulsor rotor is separate from the gas generator portion of the engine.
[0048] Another engine embodiment 400 is illustrated in FIG. 2B . In embodiment 400 , a fan rotor 402 is driven by a fan drive turbine 408 through a gear reduction 404 . A lower pressure compressor 406 is also driven by the fan drive turbine 408 . A high pressure turbine 412 drives a high pressure compressor 410 . A combustor section 414 is located between the compressor sections 406 / 410 and turbine sections 412 / 408 . In such engines, the fan 402 now rotates at a slower speed than it would have in a direct drive engine.
[0049] All of the engines illustrated in FIGS. 1 , 2 A, and 2 B lack a high speed fan delivering air into the inlet of the engine. As such, they all face the challenges with regard to receiving sufficient air volume.
[0050] Further details of the bleed line or port 40 and an associated air supply system are shown in FIGS. 3 and 4 .
[0051] As shown in FIG. 3 , an air supply system 190 incorporates a manifold 192 provided with a plurality of bleed lines or ports 194 and which communicate with an intermediate compressor case 200 . The intermediate compressor case 200 is positioned between the low pressure compressor 30 and the high pressure compressor 26 .
[0052] The pressure of the air supplied by the low pressure compressor 30 will vary dramatically during operation of an associated engine. Thus, at some point, the air pressure delivered from the ports 194 may be undesirably high.
[0053] A supply of lower pressure air is used to address this concern. An inlet 202 to a low pressure manifold 199 communicates through a heat exchanger 206 . The heat exchanger 206 may be utilized to cool oil at other locations. A particle separator 204 is positioned to filter dirt particles out of an air supply stream being delivered downstream through fans 208 a and 208 b to an air supply line 211 . Air supply line 211 may communicate through a valve 212 to a mixing box 198 . The valve 212 is controlled in combination with a valve 196 associated with the manifold 192 , such that the flow of air from the higher pressure manifold 192 and the lower pressure source 211 , are properly mixed to achieve a desired pressure at an outlet 310 . The outlet 310 leads to an environmental control system 400 for supplying air for use on an associated aircraft.
[0054] A control, such as a full authority digital engine control, may control the valves 196 and 212 , based upon the pressure, temperature and any other variables within the operation of the associated engine.
[0055] A worker of ordinary skill in the art would recognize how to achieve a desired pressure at the outlet 310 . The desired pressure at the outlet 310 may be dictated by the aircraft manufacturer.
[0056] When the valve 212 is open, air flows from the source 211 through the mixing box 198 . However, as the valve 212 is moved toward a more closed position, that air is delivered through an outlet 214 downstream of the high pressure compressor 26 .
[0057] FIG. 4 shows an alternative embodiment 250 . Alternative embodiment 250 is generally the same as the embodiment 190 . An inlet 302 leads into a low pressure supply manifold 300 . There is a dirt separator 304 , a heat exchanger 306 and fans 308 a and 308 b. Valves 312 and 296 are controlled to control the pressure of the air reaching a mixing box 298 which communicates with an outlet 311 , and eventually the environmental control system 400 . A pipe 510 communicating a lower pressure air supply into the mixing box 298 passes air through a one-way valve 420 and to the outlet 512 , similar to the first embodiment.
[0058] As mentioned above, with an embodiment such as shown in FIG. 2B , there may not be sufficient air delivered for all of the uses anticipated by FIGS. 3 and 4 . The same is true with the engines shown in FIGS. 1 and 2A .
[0059] Thus, the present invention utilizes two fans 208 A and 208 B to assist in driving the air flow. The two fans 208 A and 208 B are shown in FIG. 5 downstream of the heat exchanger 306 . They will serve to induce air flow into two conduits 219 A and 219 B, which will go to distinct applications, such as are shown, for example, in FIGS. 3 and 4 . Impellers 209 A and 209 B are shown associated with each fan. A control 400 is shown schematically for controlling the speed of the impellers 209 A and 209 B. Now, by controlling the relative speeds of the two fans 208 A and 208 B, the amount of air delivered into the two conduits 219 A and 219 B can be controlled.
[0060] As can be appreciated, the control 400 can control the fan impellers 209 A and 209 B to rotate at distinct speeds. Alternatively, the fans 208 A and 208 B may also be provided with distinct sizes such that they deliver distinct volumes of airflow into conduits 219 A and 219 B. Should the location receiving air from the conduit 219 A require more air than the location receiving air from the conduit 219 B, than the impeller 209 A may be driven at a higher speed than the impeller 209 B to deliver increased airflow to the conduit 219 A.
[0061] In addition, the required volume by the various locations and systems receiving air will vary during flight operation. Thus, the control 400 will be programmed to anticipate the change in airflow volume needs of the system, and to modify the speed and hence the volume of airflow provided by the impellers 209 A and 209 B, as appropriate. Thus, a sufficient quantity of air will be provided for the various applications that may be required on an aircraft application.
[0062] Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the true scope and content of this disclosure.
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A gas turbine engine has a first source of air to be delivered into a core of the engine, and a second source of air, distinct from the first source of air and including separately controlled first and second fans, each delivering air into respective first and second conduits connected to distinct auxiliary applications.
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CLAIM OF PRIORITY
[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/846,273, filed on Jul. 15, 2013, the benefit of priority of which is claimed hereby, and which is incorporated by reference herein in its entirety.
BACKGROUND
[0002] A human hip joint connects a femur (sometimes referred to as a thigh bone) to an acetabulum (sometimes referred to as a hip socket) of the pelvis. Hip joints support the weight of a human body, and are important for retaining balance.
[0003] Some types of injury, disease, or degeneration can produce pain and/or restricted motion in a hip joint. One treatment for certain types of damage to a hip joint is surgery. For severe damage, the hip can be surgically replaced.
OVERVIEW
[0004] Hip replacement surgery (hip arthroplasty) can include implantation of a distal stem into a femur of a patient, and implantation of a proximal body to connect to the distal stem. Implantable proximal bodies can be presented to a practitioner in the form of a set. The implantable proximal bodies in the set can include discrete combinations of the parameters of height (i.e., the length of the femur) and offset (i.e., the lateral distance from the central axis of the femur to the center of the femoral head in the acetabulum). Height and offset are established quantities in the field of hip replacement surgery.
[0005] FIG. 1 shows an exemplary set 1 of implantable proximal bodies. The set 1 includes twelve parts, each part being a different combination of height and offset.
[0006] In general, the values of height and offset in the set 1 are selected to accommodate the anatomy of most patients, so that at least one of the twelve permutations ensures a suitable fit for the implantable proximal body. In the example of FIG. 1 , there are four values of height, including 60 mm, 70 mm, 80 mm, and 90 mm. In the example of FIG. 1 , there are three values of offset, including 35 mm, 40 mm, and 45 mm. The values of height and offset in FIG. 1 are but one example, and that other suitable values may also be used.
[0007] In order to determine the most appropriate height and offset for a particular patient, a practitioner uses a “trial” or “provisional”, which is shaped and sized similar to the implantable parts, but is removable and can be reused or disposed of. In conventional practice, a practitioner tries on various sizes by temporarily attaching the trial to a stem, and noting the fit of the trial with the anatomy of the patient. Once a best fit is found, the practitioner notes the values of height and offset of the trial that provides the best fit. The practitioner removes the trial, selects an implantable proximal body from the set 1 , the selected body having height and offset values that are closest to the noted values, and implants the selected implantable proximal body.
[0008] FIG. 2 is a schematic drawing of an exemplary kit 10 of adjustable trials. A practitioner can use the trial kit 10 for determining a suitable height and offset of an implantable proximal body for hip replacement surgery. The trial kit 10 includes a fixed portion 20 , and several adjustable portions 30 that can releasably lock to the fixed portion 20 at discrete locations. A practitioner selects one of the adjustable portions 30 , which has a particular, fixed, value of offset associated with it, and slides it from discrete location to discrete location along the fixed portion 20 to determine a fit of the trial at various heights.
[0009] The fixed portion 20 can removably attach to an upper end of a stem 40 . The stem 40 can be implanted at an upper end of a femur of a patient, or can be a trial part that is removably disposed at the upper end of the femur. The stem 40 is not part of the trial kit 10 . The fixed portion 20 has a longitudinal axis (A) extending in a vertical direction.
[0010] The fixed portion 20 has a plurality of indentations 25 A, 25 B, 25 C, 25 D on its exterior surface at specified locations along the longitudinal axis. In the example of FIG. 1 , there are four indentations, corresponding to the height values of implants in the set 1 ; in other examples, there may be two, three, five, six, or more than six indentations.
[0011] The trial kit 10 includes a plurality of adjustable portions 30 A, 30 B, 30 C, each with a different value of offset. In the example of FIG. 1 , there are three adjustable portions, corresponding to the offset values of implants in the set 1 ; in other examples, there may be two, four, five, six, or more than six adjustable portions. The adjustable portions 30 A, 30 B, 30 C are intended to be used one at a time, in combination with the fixed portion 20 . Each adjustable portion 30 A, 30 B, 30 C slides vertically along the fixed portion 20 .
[0012] Each adjustable portion 30 A, 30 B, 30 C includes a movable element 35 A, 35 B, 35 C that is biased to contact the exterior surface of the fixed portion 20 , such as by spring loading. As the adjustable portion 30 A, 30 B, 30 C slides along the fixed portion 20 , the movable element 35 A, 35 B, 35 C snaps into one of the indentations 25 A, 25 B, 25 C, 25 D. The snapping releasably locks the adjustable portion 30 A, 30 B, 30 C to the fixed portion 20 .
[0013] Each adjustable portion 30 A, 30 B, 30 C can have a hand-deployed release mechanism, which can retract the movable element 35 A, 35 B, 35 C from one of the indentations 25 A, 25 B, 25 C, 25 D and unlock the adjustable portion 30 A, 30 B, 30 C from the fixed portion 20 .
[0014] FIG. 3 is a schematic drawing of an adjustable trial 50 , as used during a surgical procedure. The adjustable trial 50 can be part of the trial kit 10 of FIG. 1 . Prior to surgery, a practitioner can examine one or more X-rays or other images of the anatomy of the patient. The anatomy images can provide the practitioner with a good estimate of the offset value, and, optionally, a rough estimate of the height value. During surgery, the practitioner selects an adjustable portion 30 that has an offset value that best corresponds to the estimate. The practitioner slides the selected adjustable portion 30 vertically along the fixed portion 20 from indentation to indentation, checking a fit of the trial at each height value, in order to determine a best height value. The adjustable portion 30 locks at each indentation, so that the practitioner can determine how well the particular offset and height values fit the patient while the adjustable trial 50 is in the locked position.
[0015] In some examples, if the practitioner wishes to determine a fit with more than one offset value, the practitioner can remove one adjustable portion from the fixed portion 20 and use another adjustable portion from the trial kit 10 . Once the practitioner has determined the offset and height values that provide the best fit for the patient, the practitioner notes the best fit offset and height values, removes the adjustable portion 30 from the fixed portion 20 , removes the fixed portion 20 from the stem 40 , selects an implantable proximal body having the noted best fit offset and height values, and surgically implants the selected implantable proximal body onto the stem 40 . Following the surgery, the adjustable trial 50 , as well as other adjustable trials in the trial 10 , can be cleaned, sterilized, and reused for subsequent surgical procedures. Alternatively, the adjustable trial 50 can be designed for a single use, and can be disposed of following a procedure.
[0016] There are several advantages to using the trials discussed herein. For instance, a kit of the adjustable trials can include fewer parts than a comparable kit of non-adjustable trials. For example, in the trial kit 10 in FIG. 2 , the kit includes three parts, plus a fixed portion, compared with the twelve parts that would be required from the comparable kit of non-adjustable trials. In addition, adjusting the trial during surgery can be significantly quicker than removing one non-adjustable trial from the distal stem and attaching another non-adjustable trial to the distal stem. This can save time and effort for a practitioner.
[0017] It will be understood that the adjustable portions and fixed portions shown in FIGS. 2 and 3 are but high-level schematic representations of these parts. In practice, the actual parts can include multiple elements and features that are not shown in FIGS. 2 and 3 . FIGS. 4-7 show an exemplary full mechanical configuration for an adjustable trial 100 .
[0018] This Overview is intended to provide examples of the present patent document. It is not intended to provide an exclusive or exhaustive explanation of the invention. The Detailed Description below is included to provide further information about the present adjustable trial, kit of adjustable trials, and the corresponding methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In the drawings, which are not necessarily drawn to scale, like numerals describe similar components in different views. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present patent document.
[0020] FIG. 1 is a schematic drawing of an exemplary set of implantable proximal bodies.
[0021] FIG. 2 is a schematic drawing of an exemplary system of adjustable trials.
[0022] FIG. 3 is a schematic drawing of an adjustable trial, as used during a surgical procedure.
[0023] FIG. 4 is an exploded view of an exemplary adjustable proximal trial.
[0024] FIG. 5 is an exploded view of the adjustable portion from the adjustable proximal trial of FIG. 3 .
[0025] FIG. 6 is a partial cross-section view of the adjustable portion of FIG. 5 .
[0026] FIG. 7 is a cross-section side view of the assembled adjustable proximal trial of FIGS. 4-6 .
[0027] FIG. 8 is a flow chart of a method of using the adjustable proximal trial of FIGS. 4-7 .
DETAILED DESCRIPTION
[0028] FIG. 4 is an exploded view of the elements in an exemplary adjustable trial. The example adjustable proximal trial 100 includes a fixed portion 102 , which removably attaches to a stem, and an adjustable portion 104 , which releasably attaches at discrete locations to the fixed portion 102 .
[0029] The fixed portion 102 includes four elements 170 , 160 , 150 , 140 , all of which are coaxial with a longitudinal axis (A) of the fixed portion 102 . A lower body 170 attaches to an upper end of the distal stem, a lower bolt 160 attaches the lower body 170 to the distal stem 40 ( FIG. 1 ), an optional upper extension 150 upwardly extends the length of the lower body 170 , and an optional upper bolt 140 attaches upper extension 150 to the lower body 170 . Breaking the longitudinal length of the fixed portion 102 into two portions, namely the lower body 170 and the upper extension 150 , allows the lower bolt 160 to be tightened and loosened using a common tool, such as a standard hex key, rather than an elongated, customized tool.
[0030] FIG. 4 shows the lower body 170 being generally cylindrical in shape, with the longitudinal axis (A) extending vertically from the proximal (upper) direction to the distal (lower) direction. The lower body 170 has a cylindrical volume 178 in its interior. The cylindrical volume 178 can be accessed from a lower end of the lower body 170 . During operation, the upper end of the distal stem extends into the cylindrical volume 178 of the lower body 170 , as shown in FIGS. 2 and 3 . The wall of the cylindrical volume 178 is sized and shaped to match an exterior surface of the distal stem, so that the lower body 170 can fit snugly, but removably, over the upper end of the distal stem.
[0031] An upper end of the lower body 170 can include one or more notches 172 around its circumference. The notches 172 can seat the upper extension 150 thereon during assembly of the device. In some examples, the upper end of the lower body 170 can be crenellated instead. The purpose is to prevent rotational misalignment between the upper and lower bodies. The lower body 170 includes female threads 176 at its upper end, which can couple with corresponding male threads 142 on the upper bolt 140 .
[0032] The lower body 170 can include an optional keying feature, which can prevent or reduce angular misalignment about the longitudinal axis (A) between the adjustable portion 104 and the fixed portion 102 while still allowing these two pieces to slide vertically along axis A. Such a keying feature can be an elongation or irregularity on an outer profile of the fixed portion 102 , which mates with a complementary elongation or irregularity on an inner bore 122 within the adjustable portion 104 . For instance, the fixed portion 102 of FIG. 4 includes a spine 174 , which extends longitudinally along an outer edge of the lower body 170 . The spine 174 can extend into a corresponding groove 132 in the adjustable portion 104 . Other suitable keying features may also be used.
[0033] An exterior surface 179 of the lower body 170 includes one or more indentations 182 , 184 . In some examples, the indentations 182 , 184 are disposed along a line parallel to the longitudinal axis (A). In some examples, one or more of the indentations 182 , 184 extend partially or fully through a wall of the lower body 170 . In some examples, the indentations 182 , 184 and the spine 174 are on opposite sides of the lower body 170 . In the example of FIG. 4 , there are two indentations 182 , 184 on the lower body 170 ; in other examples there can be zero, one, three, four, or more than four indentations on the lower body 170 .
[0034] The lower bolt 160 attaches the lower body 170 to the distal stem. When a practitioner installs an adjustable trial, the practitioner places the lower body 170 over the upper end of the distal stem, then installs the lower bolt 160 to secure the lower body 170 to the distal stem. The lower bolt 160 includes male threads 162 at or near its lower end. When installed, the male threads 162 engage corresponding female threads on the upper end of the distal stem. The lower bolt 160 can be tightened and loosened by inserting a suitable key into one or more sockets 164 at its upper end. In the specific example of FIG. 4 , the socket 164 is sized and shaped to accommodate a 3.5 mm hex key; other suitable socket sizes and shapes can also be used.
[0035] The upper extension 150 upwardly lengthens the lower body 170 . The upper extension 150 is cylindrical in shape, with an open upper end and an open lower end. The upper extension 150 is sized to match the size and shape of the upper end of the lower body 170 . The upper extension 150 can include one or more teeth 152 at its lower end, to couple with corresponding notches 172 at the upper end of the lower body 170 . In some examples, the lower end of the upper extension 150 is crenellated, with a complementary crenellation to that of the upper end of the lower body 170 . In other examples, one or more teeth can be disposed on the upper end of the lower body 170 , and one or more notches can be disposed on the lower end of the upper extension 150 . The upper extension 150 can include a spine 154 that aligns with the spine 174 on the lower body 170 . The spines 154 , 174 can extend into a corresponding groove 132 in the adjustable portion, and can be a keying feature of the fixed portion 102 . An exterior surface 156 of the upper extension 150 includes one or more indentations 186 , 188 . In some examples, the indentations 186 , 188 align with the indentations 182 , 184 on the lower body 170 . In the example of FIG. 4 , there are two indentations 186 , 188 on the upper extension 150 ; in other examples there can be zero, one, three, four, or more than four indentations on the upper extension 150 .
[0036] The upper bolt 140 attaches the upper extension 150 to the lower body 170 . The upper bolt 140 is generally cylindrical in shape, and can have a hollow interior that extends longitudinally through the upper bolt 140 . Such a hollow interior can be useful for accessing the lower bolt 160 while the fixed portion 102 is assembled. The upper bolt 140 is inserted into the upper end of the upper extension 150 , and extends distally past the lower end of the upper extension 150 into the lower body 170 . The upper bolt 140 has male threads 142 that engage the corresponding female threads 176 in the lower body 170 . A practitioner can tighten and loosen the upper bolt 140 by inserting a suitable key into a socket 144 at the upper end of the upper bolt 140 . In the example of FIG. 4 , the socket 144 is sized and shaped to accommodate an 8 mm hex key; other suitable socket sizes and shapes can also be used.
[0037] FIG. 5 shows adjustable portion 104 , which includes a housing 110 and three smaller elements 114 , 116 , 118 .
[0038] The adjustable portion 104 includes a movable element 130 that is biased to contact the exterior surface 156 , 179 of the fixed portion 102 . When the adjustable portion 104 slides to one of the indentations 182 , 184 , 186 , 188 , the movable element 130 snaps into the respective indentation to lock the adjustable portion 104 to the fixed portion 102 .
[0039] The housing 110 has a bore 122 therethrough, which can accommodate the fixed portion 102 during operation. The bore 122 is coaxial with the longitudinal axis (A) of the fixed portion 102 . The bore 122 is sized and shaped to accommodate the exterior surface 156 , 179 of the fixed portion 102 with a clearance sufficient to allow the adjustable portion 104 to slide vertically along the fixed portion 102 . The bore 122 can include a groove or ridge 132 that can mate with the spines 154 , 174 on the fixed portion 102 .
[0040] The housing 110 can extend laterally away from the bore 122 to a mounting ridge 112 . A generally spherical head (not shown) can be attached to the mounting ridge 112 .
[0041] A spring-loaded element 116 is attached to the housing 110 . A pivot pin 114 extends through a hole 126 in the spring-loaded element 116 , and allows the spring-loaded element 116 to pivot around the pivot pin 114 . The pivot pin 114 attaches the spring-loaded element 116 to the housing 110 , through hole 124 in the housing. The movable element 130 can be disposed at one end of the spring-loaded element 116 .
[0042] The adjustable portion 104 optionally includes a hand-deployed release mechanism that retracts the movable element 130 from the indentation to unlock the adjustable portion 104 from the fixed portion 102 in order to move it to a different indentation if desired. An example of a release mechanism is a depressable portion, such as a push button, that is pivotally arranged to counteract the biasing effect. For instance, if the biasing element is a spring, and expansion of the spring forces the movable element against the exterior surface of the fixed portion, then the push button can be arranged to compress the spring when pushed, so as to counteract the bias of the spring.
[0043] The hand-deployed release mechanism can include one or more of a depressable portion 120 , the pivot pin 114 , a spring 118 , and the movable element 130 . Other suitable hand-deployed release mechanisms may also be used. The depressable portion 120 can be disposed at an opposite end of the spring-loaded element 116 . The spring 118 biases the spring-loaded element 116 against the housing 110 , so that the movable element 130 is biased to contact the exterior surface 156 , 179 of the fixed portion 102 . During use, a practitioner can use a single hand to release the adjustable portion 104 from the fixed portion 102 , for instance, by depressing the depressable portion 120 with a thumb to release the movable element 130 from an indentation in the fixed portion 102 .
[0044] FIG. 6 shows a partial cross-section of the adjustable portion 104 of FIG. 5 , in an assembled state.
[0045] FIG. 7 is a side cross-section of an assembled trial implant, to illustrate how the components of FIGS. 4-6 fit together. FIG. 7 also shows an optional feature that can ease adjustments of height during use.
[0046] The shapes of the movable element 130 and the indentations 182 - 188 can influence the locking behavior of the adjustable trial 100 . For instance, an upper edge of the movable element 130 and an upper edge of at least one of the indentations 182 , 184 , 186 , 188 can be gently sloped away from the longitudinal axis. For these gentle slopes, when the adjustable portion 104 is locked to the fixed portion 102 , applying an upward translational force to the adjustable portion 104 forces the movable element 130 radially outward from the respective indentation 182 , 184 , 186 , 188 , and unlocks the adjustable portion 104 from the fixed portion 102 . In contrast, a lower edge of the movable element 130 and a lower edge of at least one of the indentations 182 , 184 , 186 , 188 can be more steeply sloped away from the longitudinal axis. For these steep slopes, the movable element 130 remains extended into the respective indentation 182 , 184 , 186 , 188 in the presence of an upward or downward force on the adjustable portion 104 . For these cases, the movable element 130 can be refracted by use of the hand-deployed release mechanism. In the example of FIGS. 4-7 , the hand-deployed release mechanism includes the depressable portion 120 and the movable element 130 . In other examples, the lower edges are gently sloped, while the upper edges are steeply sloped. In still other examples, both the lower and upper edges are gently sloped; for these cases, the adjustable portion 104 can be unlocked from the fixed portion 102 by forcing the adjustable portion 104 upward or downward, which can eliminate the need for a mechanism such as depressable portion 120 in FIGS. 4-6 . In still other examples, both the lower and upper edges are steeply sloped.
[0047] FIG. 7 also shows an exemplary set of definitions for offset and height. Offset can be defined as a lateral distance between a longitudinal axis (A) of the proximal body and a junction feature found on the adjustable portion 104 , such as the mounting ridge 112 . Height can be defined as a longitudinal distance between an upper end of the distal stem at the junction feature, such as the mounting ridge 112 , found on the adjustable portion 104 . In some examples, the height values are equally spaced apart; in other examples, the height values are unequally spaced.
[0048] In the configurations of FIGS. 2-7 , the adjustable portions have a fixed value of offset. In other configurations, the adjustable portions can have adjustable values of offset (not shown). In some of these configurations, the offset is adjustable in discrete increments that can correspond to offset values available in a set of implantable proximal bodies.
[0049] FIG. 8 is a flow chart of an example method 800 for selecting a suitable height and offset of an implantable proximal body from a set of implantable proximal bodies for hip replacement surgery. Each implantable proximal body in the set has a different combination of offset value, included in a discrete plurality of offset values, and height value, included in a discrete plurality of height values. The selection method 800 can be executed using the generic trial kit 10 and adjustable trial 50 , shown in FIGS. 2 and 3 , or using the specific exemplary configurations of FIGS. 4-7 .
[0050] Step 802 attaches a fixed portion of an adjustable trial to an upper end of a stem. The fixed portion can include a plurality of indentations. Each indentation can correspond to a height value in the discrete plurality of height values. Step 804 slides a first adjustable portion along the fixed portion to engage a first indentation in the plurality. The first adjustable portion can have a first height value when the first indentation is engaged. Step 806 compares the first adjustable portion at the first height value to an anatomy of a patient to determine a first fit. Step 808 slides the first adjustable portion along the fixed portion to engage a second indentation in the plurality. The first adjustable portion can have a second height value when the second indentation is engaged. Step 810 compares the first adjustable portion at the second height value to the anatomy of a patient to determine a second fit. Step 812 selects the best fit for the patient from the first and second fits. Step 814 selects an implantable proximal body from the set. The selected implantable proximal body can have the offset value of the first adjustable portion and can have the height value of the first adjustable portion at the best fit. Step 816 removes the fixed portion of the adjustable trial from the upper end of the stem, and implants the selected implantable proximal body onto the upper end of the stem.
[0051] The above Detailed Description includes references to the accompanying drawings, which form a part of the Detailed Description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.
[0052] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, kit, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.
[0053] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) can be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
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Hip replacement surgery (hip arthroplasty) includes implantation of a distal stem into a femur of a patient, and implantation of a proximal body to connect to the distal stem. A practitioner uses a “trial” or “provisional” to determine a suitable size and configuration for the implantable proximal body, then selects a suitable proximal body from a set of differently sized and shaped proximal bodies. The trial adjusts discretely, as opposed to continuously, and has discrete settings that correspond to the sizes and configurations available in the set of implantable proximal bodies. In some examples, the trials are provided as a kit of parts, where each part in the kit is adjustable for height (i.e., the length of the femur). The parts in the kit can have different, fixed, values for offset (i.e., the lateral distance of the femur to the center of the femoral head in the acetabulum).
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority from U.S. Provisional Application Serial No. 60/197,280 filed Apr. 14, 2000, by applicants Nathaniel J. Fisch and Yevgeny Raitses, the disclosure of which is incorporated herein by reference.
CONTRACTUAL ORIGIN OF THE INVENTION AND STATEMENT AS TO FEDERALLY SPONSORED RESEARCH
Pursuant to 35 U.S.C. 202(c), it is acknowledged that the U.S. Government has certain rights in the invention described herein which was made in part with funds from the Department of Energy under Grant No. DE-AC02-76-CHO-3073 under contract between the U.S. Department of Energy and Princeton University. Princeton University has served notice that it does not wish to retain title to this invention.
BACKGROUND OF THE INVENTION
The present invention pertains generally to electric plasma thrusters and more particularly to Hall field thrusters, which are sometimes called Hall accelerators.
The Hall plasma accelerator is an electrical discharge device in which a plasma jet is accelerated by a combined operation of axial electric and magnetic fields applied in a coaxial channel. The conventional Hall thruster overcomes the current limitation inherent in ion diodes by using neutralized plasma, while at the same time employing radial magnetic fields strong enough to inhibit the electron flow, but not the ion flow. Thus, the space charge limitation is overcome, but the electron current does draw power. Hall thrusters are about 50% efficient. Hall accelerators do provide high jet velocities, in the range of 10 km/s to 20 km/s, with larger current densities, about 0.1 A/cm 2 , than can conventional ion sources.
Hall plasma thrusters for satellite station keeping were developed, studied and evaluated extensively for xenon gas propellant and jet velocities in the range of about 15 km/s, which requires a discharge voltage of about 300 V. Hall thrusters have been developed for input power levels in the general range of 0.5 kW to 10 kW. While all Hall thrusters retain the same basic design, the specific details of an optimized design of Hall accelerators vary with the nominal operating parameters, such as the working gas, the gas flow rate and the discharge voltage. The design parameters subject to variation include the channel geometry, the material, and the magnetic field distribution.
A. V. Zharinov and Yu. S. Popov, “Acceleration of plasma by a closed Hall current”, Sov. Phys. Tech. Phys. 12, 1967, pp. 208-211 describe ideas on ion acceleration in crossed electric and magnetic field, which date back to the 1950's. The first publications on Hall thrusters appeared in the United States in the 1960's, such as: G. R. Seikel and F. Reshotko, “Hall Current Ion Accelerator”, Bulletin of the American Physical Society, II (7) (1962) and C. O. Brown and E. A. Pinsley, “Further Experimental Investigations of Cesium Hall-Current Accelerator”, AIAA Journal, V.3, No 5, pp. 853-859, 1965.
Over the last thirty years, A. I. Morozov designed a series of high-efficiency Hall thrusters. See, for example, A. I. Morozov et al., “Effect of the Magnetic field on a Closed-Electron-Drift Accelerator”, Sov. Phys. Tech. Phys. 17(3), pp. 482-487 (1972), A. I. Morosov, “Physical Principles of Cosmic Jet Propulsion”, Atomizdat, Vol. 1, Moscow 1978, pp. 13-15, and A. I. Morozov and S. V. Lebedev, “Plasma Optics”, in Reviews of Plasma Physics, Ed. by M. A. Leontovich, V.8, New York-London (1980).
H. R. Kaufman, “Technology of Closed Drift Thrusters”, AIAA Journal Vol. 23 p. 71 (1983), reviews of the technology of Hall field thrusters, both in the context of other closed electron drift thrusters and in the context of other means of thrusting plasma. V. V. Zhurin et al., “Physics of Closed Drift Thrusters”, Plasma Sources Science Technology Vol. 8, p. R1 (1999), further reviews the physics and more recent developments in the technology of Hall thrusters.
What remains a challenge is to develop a Hall thruster able to operate efficiently with minimal plume divergence. What is a further challenge is to accomplish such operation with the same thruster in several parameter regimes, such as at different input powers or at varying output thrusts. A number of issues arise with such variable operation of Hall current accelerators. These issues include decreased thruster efficiency for low mass flow rate and for low discharge voltages. At lower mass flow rates, lower atomic density in the channel results in an increased ionization mean free path of propellant atoms. A longer ionization length reduces the ionization efficiency and increases ion losses in the channel. Moreover, an extended ionization region produces a spread of ion energies, including slow ions. These slow ions are particularly vulnerable to radial accelerations and so contribute importantly to the plume divergence. This is a crucial issue even for non-variable operation. A similar effect would be incurred through the use of not easily ionized gases.
The present invention comprises an improvement over the prior art cited above by providing for efficient operation, with decreased plume divergence, and with capability for variable operation. The present invention discloses means of accomplishing these objectives through the placement of segmented electrodes along the inner and outer channel walls with the electrode segments held at specific potentials that lead to the improved operation.
The present invention comprises an improvement as well as over the following prior art:
U.S. Pat. No. 4,862,032 (“End-Hall ion source”, Kaufman et al., Aug. 29, 1989) discloses specifically that the magnetic field strength decreases in the direction from the anode to the cathode. The disclosure of the above referenced patent is hereby incorporated by reference.
Other design suggestions are disclosed in U.S. Pat. No. 5,218,271 (“Plasma accelerator with closed electron drift”, V. V. Egorov et al., Jun. 8, 1993) which contemplates a curved outlet passage. The disclosure of the above referenced patent is hereby incorporated by reference. U.S. Pat. No. 5,359,258 (“Plasma accelerator with closed electron drift”, Arkhipov et al., Oct. 25, 1994) contemplates improvements in magnetic source design by adding internal and external magnetic screens made of magnetic permeable material between the discharge chamber and the internal and external sources of magnetic field. The disclosure of the above referenced patent is hereby incorporated by reference.
U.S. Pat. No. 5,475,354 (“Plasma accelerator of short length with closed electron drift”, Valentian et al., Dec. 12, 1995) contemplates a multiplicity of magnetic sources producing a region of concave magnetic field near the acceleration zone in order better to focus the ions. The disclosure of the above referenced patent is hereby incorporated by reference. U.S. Pat. No. 5,581,155 (“Plasma accelerator with closed electron drift”, Morozov, et al., Dec. 3, 1996) similarly contemplates specific design optimizations of the conventional Hall thruster design, through specific design of the magnetic field and through the introduction of a buffer chamber. The disclosure of the above referenced patent is hereby incorporated by reference.
U.S. Pat. No. 5,763,989 (“Closed drift ion source with improved magnetic field”, H. R. Kaufman Jun. 9, 1998) contemplates the use of a magnetically permeable insert in the closed drift region together with an effectively single source of magnetic field to facilitate the generation of a well-defined and localized magnetic field, while, at the same time, permitting the placement of that magnetic field source at a location well removed from the hot discharge region. The disclosure of the above referenced patent is hereby incorporated by reference. U.S. Pat. No. 6,075,321 (“Hall field plasma accelerator with an inner and outer anode”, V. J. Hruby, Jun. 13, 2000) contemplates an anode that can be part of either the inner or outer walls, rather than simply part of an inlet wall, but not a series of segmented electrodes for detailed control of the axial potential. The disclosure of the above referenced patent is hereby incorporated by reference.
U.S. Pat. No. 5,847,493 (“Hall effect plasma accelerator”, Yashnov et al., Dec. 8, 1998) proposes that the magnetic poles in an otherwise conventional Hall thruster be defined on bodies of material which are magnetically separate. The disclosure of the above referenced patent is hereby incorporated by reference.
U.S. Pat. No. 5,845,880 (“Hall effect plasma thruster”, Petrosov et al., Dec. 8, 1998) proposes a channel preferably flared outwardly at its open end so as to avoid erosion. The disclosure of the above referenced patent is hereby incorporated by reference.
The closest configuration in the literature to the present invention appears to be Russian Patent SU 1796777 A1 (Yu. M. Lisikov, V. V. Gopanchuk and I. B. Sorokin, “Stationary Plasma Thruster”, Applied Jun. 28, 1991, Issued: Feb. 23, 1993, Bulletin 7, in Russian). Lysikov et al. discloses an additional internal thermionic cathode, supplementary to the cathode compensator outside the acceleration region. The internal cathode is apparently placed where the magnetic field lines are approximately radial, which is approximately at the radial magnetic field maximum. The internal cathode is positioned on the discharge chamber apparently at the potential of the external cathode. In contrast to Lysikov et al., we disclose the design and use of emissive and non-emissive electrodes specifically configured so as to control and improve the voltage profile and thereby minimize the plume divergence. The disclosure of the above referenced patent is hereby incorporated by reference.
BRIEF SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved Hall plasma thruster by means of detailed control of the electric field.
It is a further object of this invention to provide an improved plasma thruster, which provides better focusing of the ion trajectories, thereby providing a more directional plume. A more tightly focused plasma plume reduces channel erosion, improves thrust, and facilitates integration with other satellite components.
The invention exploits the fact that the lines of magnetic force form surfaces of substantially constant electric potential. Since the magnetic field lines intersect the thruster channel, the potential distribution within the channel can be determined by imposing a potential distribution on the channel, through the placement of electrodes on the channel wall. The potential drop can then be imposed in a predetermined region of the thruster channel.
In the operation of a conventional Hall thruster, the total accelerating voltage, namely the voltage drop between the cathode and the anode, is fixed. However, the specific profile of the voltage drop between the anode and the cathode is dependent upon the details of the plasma flow and the magnetic field distribution. In order to control the electric potential in detail and, in particular, independent of the magnetic field, electrode segments are inserted along the plasma channel.
If the electrodes are not emissive, then an electrostatic plasma sheath will form in the vicinity of the electrode so as to shield the thruster interior from the electrode potential. This will generally be a deleterious effect, if not carefully designed, as ions will fall through a radial potential and strike the wall to balance the electron flux to the wall. However, if emissive electrode segments are employed, cold electrons are emitted from the wall, balancing the current of hot electrons to the wall, so that a radial sheath potential will not form. The ions are then not exposed to a radial potential drop. The ions then tend not to strike the wall and will produce a more tightly focused plasma plume. We disclose herein certain configurations of emissive and non-emissive electrodes to optimize thruster performance particularly by focusing the plume.
SUMMARY OF INVENTION
The present invention discloses an apparatus and method for thrusting plasma, utilizing a Hall thruster with segmented electrodes along the channel, which make the acceleration region as localized as possible. Also disclosed are methods of arranging the electrodes along the plasma channel so as to increase efficiency and minimize erosion and arcing. Also disclosed are methods of arranging the electrodes so as to produce a substantial reduction in plume divergence. The use of electrodes made of emissive material will reduce the radial potential drop within the channel, further decreasing the plume divergence. Also disclosed is a method of arranging and powering these electrodes so as to provide variable mode operation.
Since the magnetic field lines in a Hall thruster comprise magnetic surfaces at substantially the same electric potential, the voltage in the thruster interior may be substantially defined by imposing a specified electric potential on an electrode on the periphery of said interior region, such that the magnetic field line that permeates said interior thruster region also intersects said electrode. The method of specifying the potential on this field line is by inserting an electrode within the thruster channel, held at said potential, and such that said field line intersects said electrode.
This idea can be understood with reference to FIG. 1 . FIG. 1 is a schematic representation of the plasma channel with segmented electrodes. Line 1 A— 1 A is a magnetic field line that extends from electrode segment 2 on channel wall 3 to an interior region in the thruster, which, which is approximately midway along the magnetic field line 1 A— 1 A. The magnetic field line extends to channel wall 5 . Similarly, Line 1 B— 1 B is a magnetic field line that extends from electrode segment 4 on channel wall 3 to an interior region in the thruster, which is approximately midway along the magnetic field line 1 B— 1 B, and then similarly intersects the opposite channel wall 5 . In a Hall thruster, lines 1 A— 1 A and 1 B— 1 B would be substantially in the radial direction near the maximum of the magnetic field (see FIG. 2 ). For example, channel wall 3 could be the outer thruster wall and channel wall 5 could be the inner thruster wall, although the segmented electrodes could be placed against either or both walls so long as the same magnetic field lines is intersected by the electrode.
In the absence of plasma sheath effects, magnetic field line 1 A— 1 A tends to be at the same electric potential, since electrons can move freely along the field line to cancel any potential differences. Moreover, in a Hall thruster, electrons drift in the azimuthal direction, so that all field lines that intersect the channel at the same axial position tend to form surfaces of the same electric potential. The plasma sheath potential arises in order to balance the electron current to the channel wall by an ion current to the wall. If the electron axial flow is impeded by the magnetic field, then energetic electrons strike the wall faster than the ions do, until a sheath potential develops. However, if the electron temperature is small, or if the wall surface emits electrons, the sheath potential will be correspondingly small. The sheath potential impedes electrons from entering wall, but accelerates ions towards the wall. Accordingly, the sheath potential is a cause for ion plume divergence in Hall thrusters.
In one embodiment of the invention, the plasma sheath potential is small. Then all points along magnetic field line 1 A— 1 A are at approximately the same potential. Similarly, all points along magnetic field line 1 B— 1 B are at approximately the same potential. The voltage source 6 establishes a potential drop between electrode segment 2 and electrode segment 4 . Because each field line is substantially at the same potential along its own full length, said potential drop established between magnetic field line 1 A— 1 A and magnetic field line 1 B— 1 B persists along the full length of both lines even throughout the thruster interior.
In a second embodiment of the invention, the plasma sheath effect may not be small. In said second embodiment, said electron potential along said magnetic field line 1 A— 1 A is determined partly by said potential imposed on electrode 2 and partly by electric sheath potential. However, by providing electrode 2 with emissive properties, said electrode 2 will emit electrons along magnetic field line 1 A— 1 A in such a manner as to cancel electric sheath potential.
In yet a third embodiment of the invention, the plasma sheath may not be small, yet electrodes without substantial emissive properties are employed. However, the electrodes are placed so as to minimize the plume divergence by providing for substantial axial accelerating potential in a precise and favorable region of the thruster channel.
FIG. 2 is a schematic representation Hall thruster with segmented electrode rings 7 a and 7 b on the outer ceramic channel wall 25 . Line 0 — 0 is an axis of symmetry. Segmented electrode 7 b is near the thruster exit. Hollow cathode 8 emits electrons and neutralizes the flow of ions. An accelerating voltage drop is applied between anode 14 and hollow cathode 8 , such that ions formed near the anode 14 are accelerated towards the thruster exit. The anode 14 can also be a as distributor. Magnetic field lines 10 extend from magnetic pole pieces 11 on the outer ceramic channel wall 25 and intersect magnetic pole pieces 12 on the inner ceramic channel wall 23 . Electromagnetic coils 15 generate the magnetic field, which is guided through magnetic circuit 9 to the pole pieces. (An additional optional matched set of segmented electrodes 7 c and 7 d , placed on the inner channel wall 23 supplements said segmented electrode set 7 a and 7 b , such that said segmented electrode 7 c intersects the same magnetic line of force as does electrode 7 a and is held at the potential of electrode 7 a . Similarly, said segmented electrode 7 d intersects the same magnetic line of force as does electrode 7 b and is held at the potential of electrode 7 b .)
The electron current in the conventional Hall thruster provides the space charge neutralization and also assists in the ionization. While the current is primarily in the azimuthal direction, some axial current is necessary for the charge neutralization to occur. The electrons are normally introduced only through a cathode compensator, which could be a hollow cathode 8 , outside of the main acceleration region of the ions and outside the region of intense magnetic fields. Thus, to neutralize the flow the electrons must travel axially towards the anode 14 . Anode 14 can also serve as a gas distributor. Since power dissipated is proportional to current, the extent to which current is carried by these electrons is an unavoidable inefficiency. In addition to neutralizing the space charge within the acceleration region, the cathode compensator also serves to introduce electrons that neutralize the ion flow out of the thruster and eventually recombine with the ions. Thus the cathode compensator introduces electrons flowing in opposite axial directions: both electrons that flow back towards the anode and electrons that flow with the ion stream.
In a representative embodiment, the use of the set of segmented electrodes 7 a and 7 b is disclosed as an improvement. Rather than employing the cathode compensator outside the magnetic field for a dual purpose, we disclose how these functions may be separated. In the improved configuration, the cathode compensator outside the magnetic field need introduce only electrons that flow with the ions. The flow counter to the ions can be impeded by biasing the cathode 8 relative to segmented electrode 7 b so that the ions experience a very small axial deceleration after leaving the acceleration region.
We disclose further that the set of segmented electrodes 7 a and 7 b provides a substantial voltage drop in a precise and predetermined location, thereby narrowing the ion plume and producing other advantages. We further disclose that said segmented electrodes 7 a and 7 b could be made of substantially emissive material not only to reduce deleterious effects of a plasma sheath but also to provide electrons necessary for ionization of the propellant gas. Each segment of an emissive electrode provides electrons by thermionic emission, secondary emission, field emission, capillary injection of electrons, or some other plasma producing means. The electrons so provided are available for charge neutralization, sheath reduction, or impact ionization of the neutral gas.
Note that the electrons need flow azimuthally only in the crossed electric and magnetic fields to provide the charge neutralization. Therefore, in yet another embodiment of the invention, a set of emissive segmented electrodes, such as set 7 a and 7 b , maintains the localized voltage drop at a precise and specified location within the acceleration region as well as providing for charge neutralization within the acceleration region. We disclose that the magnetic field that is imposed within the acceleration region may be allowed to be too large to permit electron axial current sufficient for ionization of the neutral gas. Instead, an additional emissive electrode segment, located between the acceleration region and the anode in a region of lower radial magnetic field, provides sufficient electrons for ionization of the neutral propellant gas. This additional electrode could be segmented electrode 7 a , which is made sufficiently emissive not only to neutralize the electron sheath along the magnetic line of force intersecting it, but also to provide sufficient electrons for ionizing the upstream gas near the anode 14 . In addition, a highly emissive segmented electrode 7 b could provide sufficient electrons for neutralizing the accelerated ions, thus effectively serving also as the cathode-neutralizer 8 .
Thus, it is a further object of the present invention to provide the electron current only where it is needed. The invention may thus be thought of also as a means of replacing some or all of the functions of the hollow cathode compensator 8 . The consequence will be to reduce the electron power loss and thus improve the thruster efficiency of operation. Moreover, since the axial electron current is not essential in the acceleration region, higher magnetic fields can be used, without impeding the axial electron flow necessary for ionization. The use of high magnetic fields results in higher thrust density, since the thrust density cannot exceed the highest magnetic field energy density.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of how segmented electrodes inserted into the plasma channel can impose a predetermined and localized potential drop in the thruster interior. Line 1 A— 1 A is a magnetic field line that extends from electrode segment 2 on channel inner wall 3 to an interior region in the thruster, and then to outer wall 5 of the thruster. Similarly, Line 1 B— 1 B is a magnetic field line that extends from electrode segment 4 on inner channel wall 3 to an interior region in the thruster, and then to outer channel wall 5 of the thruster.
FIG. 2 is a schematic representation Hall thruster with segmented electrode rings 7 a and 7 b on the outer ceramic channel wall 25 . Line 0 — 0 is an axis of symmetry. Segmented electrode 7 b is near the thruster exit. Hollow cathode 8 emits electrons and neutralizes the flow of ions. An accelerating voltage drop is applied between anode 14 and hollow cathode 8 , such that ions formed near the anode 14 are accelerated towards the thruster exit. The anode 14 can also be a gas distributor. Magnetic field lines 9 extend from magnetic pole pieces 11 on the outer ceramic channel wall 25 and intersect magnetic pole pieces 12 on the inner ceramic channel wall 23 . Electromagnetic coils 15 generate the magnetic field, which is guided through magnetic circuit 9 to the pole pieces. (An additional optional matched set of segmented electrodes 7 c and 7 d , placed on the inner channel wall 23 supplements said segmented electrode set 7 a and 7 b , such that said segmented electrode 7 c intersects the same magnetic line of force as does electrode 7 a and is held at the potential of electrode 7 a . Similarly, said segmented electrode 7 d intersects the same magnetic line of force as does electrode 7 b and is held at the potential of electrode 7 b .)
FIG. 3 is a schematic representation Hall thruster with segmented electrode ring 7 a on the outer ceramic channel wall 25 and segmented electrode ring 7 d , placed on the inner channel wall 23 , thereby minimizing the possibility of electrical breakdown.
FIG. 4 shows an example of a non-emissive segmented electrode 7 d (see for example FIG. 3 ). The electrode, which can be made from graphite, is placed on the inner channel wall 23 at the thruster exit. The electrode 7 d is attached to the wall 23 by the side 13 . To adjust the electrode location on the wall, the side 13 has a step 26 , which has outer diameter equal to the inner diameter of the channel wall 23 . The side 27 of the electrode faces the plasma. The outer side 16 has a hole 17 for a screw to fix the electrode onto the magnetic pole 12 . This screw must be electrically isolated from the electrode and from the pole. For example, it can be made from a ceramic material. In addition, the threaded holes 18 allow electrical connection between the segmented electrode and the biased supply cable. The outer side 16 , including all screw heads on this side, is covered by the protective dielectric layer 19 to avoid direct contact with plasma.
DETAILED DESCRIPTION OF THE INVENTION
The invention results from the realization that a more efficient, high performance plasma accelerator with closed electron drift can be achieved by employing segmented electrodes along the plasma channel so as to produce localized potential drops in the plasma interior. It is further anticipated that emissive electrodes will reduce the sheath potential in the plasma channel. An additional benefit is that these electrodes may also collect low energy ions.
In one representative design, but in no way meant to limit variations on this design, the electrodes can be ring-shaped, and fit into grooves or otherwise attached in the outer wall or in the inner wall. These electrodes can be of different thickness and heights. These electrodes can also be combined from several thin rings and electrically isolated from each other. The electrode surface in contact with the plasma can be flat with the ceramic channel or extend above the channel. We disclose that we have found advantages to having the segmented electrode on the anode-side extend into the channel, particularly at low mass-flow rates, thereby reducing the channel cross sectional area in order to keep the ionization high. At high mass-flow rates, we disclose that there are advantages to keep the segmented electrode ring indented relative to the surface of the ceramic channel, thereby reducing the sputtering of the electrode.
The segmented electrodes can be connected to a bias power supply. Said bias power supply can be the main discharge power supply, a separate power supply, or a power supply though a separate electric circuit from the main discharge power supply with a different potential applied such a via a resistor. In the case of several segmented electrodes, each ring can be biased separately at different potentials, from the same or separate power supplies or separate electric circuits. We further disclose that operating segmented electrodes at the local floating potential, rather than at a bias potential, can also be advantageous. Dielectric insulators can separate the electrodes. The radial magnetic field provides magnetic insulation so that very abrupt potential drops, and a very localized acceleration region, can be established in the thruster channel. The localization can be in a region of concave magnetic field for maximum focusing, resulting in less plume divergence.
The electrodes can either be non-emissive or emissive. Non-emissive segmented electrodes can be made from a low sputtering material such as graphite or graphite modifications such as carbon-carbon fibers, tungsten, or molybdenum. Emissive segmented electrodes can be made from high-temperature low sputtering and low work function materials. Said materials include LaB6, dispenser tungsten, and barium oxide. To provide higher emissivity, additional external heating can be supplied from a heating filament inserted into the electrode structure. We disclose that if the filament heater is made from a wire, said wire could be twisted in order to limit any deleterious magnetic fields associated with the current flowing through the filament.
We disclose that the electrodes are configured so as to produce a potential drop over a narrow region, in particular over that region where the magnetic field lines are substantially in the radial direction. Pairs if electrodes, such as segmented electrode 7 a and 7 b (with reference to FIG. 2) accomplish this narrow potential drop. Through the use of emissive electrodes, this potential drop can be produced more effectively over a narrow region, since the plasma sheath will not form effectively. We disclose that it is possible to achieve plume narrowing even with a single segmented electrode at near the cathode potential, provided that said electrode is placed somewhat to the cathode-side of the magnetic field maximum, although better performance can be achieved by employing also an electrode biased near the anode potential on the anode side of the maximum in the magnetic field. Some details of specific desirable electrode placement can be found in the literature (Raitses et al., “Plume Reduction in Segmented Electrode Thruster,” Journal of Applied Physics 88, 1263, August 2000; Fisch et al., “Variable Operation of Hall Thruster with Multiple Segmented Electrodes”, Journal of Applied Physics 89, 2040, February 2001), said details being covered also in U.S. Provisional Application Serial No. 60/197,280, filed Apr. 14, 2000, through which the present application seeks priority.
Note that the present application differs from Lysikov et al. (SU 1796777 A1, 1993). Lysikov et al. discloses an additional internal thermionic cathode, supplementary to the cathode compensator outside the acceleration region. The internal cathode is apparently placed where the magnetic field lines are approximately radial, which is approximately at the radial magnetic field maximum. The internal cathode is positioned on the discharge chamber apparently at the potential of the external cathode. Lysikov et al. evidently contemplates the main potential difference to appear between the anode and the internal thermionic cathode. However, the bulk of this potential drop will then occur where the magnetic field lines are not purely radial. Moreover, Lysikov et al. contemplates a thermionic electrode, rather than an emissive electrode. The thermionic electrode is a relatively small wire and the emission from it will be space-charge limited, resulting in a potential drop between the thermionic electrode and the plasma. Thus, the accelerating ions in the center of the thruster will experience considerable acceleration past the radial magnetic field maximum as well, including the radial acceleration that leads to the plume divergence. Because the thermionic cathode is relatively small, it is also the case that it does not intersect much of the fringing magnetic field, so that the full fringing magnetic field is not constrained to the same electric potential. Thus, considerable ion acceleration can take place in the fringing field where the direction of acceleration has significant radial components, further enlarging the plume.
In contrast to Lysikov et al., the present invention contemplates the use of emissive and non-emissive electrodes. These electrodes are contemplated to be considerably longer in the axial direction than the thermionic cathode suggested by Lisikov et al. The longer length means that if emissive they can emit electrons over a considerably larger region. The longer length also means that, if not emissive, they can still intersect a considerable number of fringing magnetic lines of force, thereby constraining the voltage drop in the fringing region.
Moreover, in contrast to Lysikov et al., a method is disclosed here such that the potential drop occurs where the magnetic field lines are radial, said method requiring a segmented electrode on the cathode side of the magnetic field maximum. Moreover, to narrow the region of the potential drop, the use and placement of pairs of segmented electrodes is disclosed here. The steeper the potential drop, the more narrow can be the plume divergence. Additionally, the steeper potential drop localizes the acceleration region precisely to the optimal axial location relative to the magnetic field maximum.
The example below serves to illustrate the invention by pointing out a specific and successful laboratory implementation of the design. This example is for illustrative purposes only, and is not meant to restrict in any way the use of the invention.
In one embodiment, suitable for a thruster operating in the range of 700 watts, the outer diameter of the boron nitride thruster channel is 90 mm, the voltage between anode and hollow cathode 8 is in the range of 300 volts. Xenon gas can be used as a propellant, said xenon flowing through thruster at a rate in the range of 1.7 to 2.5 milligrams per second. The anode-side and cathode-side segmented electrodes can have about 1 mm thickness of LaB6, plated in a rhenium mesh to provide a strong structure to the emissive layer. This mesh can be mounted on a molybdenum substrate ring of 3 mm thickness for each electrode. In said embodiment, the length of the anode-side electrode is 4 mm. The length of the cathode-side electrode is 10 mm. The anode-side segmented electrode has a triangular cross-section with 5 mm height into the channel. The two electrode sides, which are not attached to the wall, have a LaB6 layer. Thus, this electrode reduces the channel cross section area by 33% at the most constricted point. In an alternative embodiment, the same sizes can be used for segmented electrodes made of tantalum.
As an example, FIG. 4 shows a non-emissive, segmented electrode, made from graphite. In an embodiment suitable for employment in the above mentioned representative laboratory implementation, the outer diameter is 54 mm. When said electrode is placed on the inner wall of the ceramic channel near the thruster exhaust, a surface of 4 mm long is in contact with the plasma. The electrode is attached to the ceramic channel. A ceramic cap covers the left side of the electrode, so that said electrode does not contact the plasma. The holes at the center of the electrode are for fixing the electrode and for electric contact.
As a further example, two segmented electrodes may be employed, one at the anode side of the thruster and one at the cathode side of the thruster (see FIG. 2 ). The use of two electrodes defines a very localized potential drop.
We disclose that low plume divergence operation is possible with just one segmented non emissive electrode, employed near the channel exit, on the cathode-side of the magnetic field maximum. For the case here considered as a representative example, the optimal placement of this non emissive electrode is centered two cm from the magnetic field maximum for thruster voltage in the range of 200-300 volts and xenon gas flow rates of 1.7 mg per second. In this case, the electrode is non emissive and is biased at the cathode potential. Full angle plume reductions of approximately 20 degrees are then obtained. However, the use of only one electrode may result in some decrease in overall efficiency. However, we disclose as a preferred embodiment that low plume divergence operation is possible without loss in efficiency if both an anode-side and a cathode-side electrode are employed. That anode-side segment tends to increase the efficiency if it is biased at the anode potential. We disclose further that the mere presence of an anode-side segmented electrode can increase the efficiency in some regimes of thruster operation even if said anode-side electrode is at floating potential. For the case considered, an anode side electrode biased at the anode potential with a ten mm spacing between anode-side and cathode-side segmented electrodes gives the highest efficiency, while retaining the decreased plume divergence.
As a preferred embodiment, we disclose that high efficiency persists even as the anode-side segmented electrode is biased at an intermediate potential. Thus, two-stage operation, similarly at high efficiency and low plume divergence, can be achieved. The use of these electrodes therefore extends considerably the parameter regimes for favorable operating characteristics of Hall plasma accelerators. Therefore, as a further preferred embodiment, we disclose that through simple switching of electrode energizing, one may achieve a variable mode of operation. For example, by maintaining the anode-side electrode at or near the anode potential, but varying the cathode-side electrode potential, variable specific impulse can be achieved within the same thruster channel and with decreased plume divergence.
As a preferred embodiment, we disclose the use of emissive electrodes rather than non emissive electrodes, to reduce further the plume divergence. We further disclose (see FIG. 3) placement of segmented electrodes on either the inner or outer chamber wall, such that adjacent electrodes are placed on opposite walls, in so-called “staggered” placement. Since the magnetic field lines form equipotential surfaces at approximately constant axial location, it makes little difference in voltage profile along which wall the segmented electrode is placed. This is particularly so when the electrode is emissive. The staggered placement of electrodes therefore produces essentially the same advantageous voltage profile. However, because the electrodes are place physically far apart, the staggered arrangement substantially reduces the likelihood of arcing between the electrodes during start-up operation and the likelihood of other deleterious electrical effects associated with closely placed electrodes.
As a further preferred embodiment, we disclose advantages to employing inner and outer segmented electrodes as in FIG. 3, where the anode-side electrode is emissive and placed on the outer channel wall, whereas the cathode-side electrode is non emissive and placed on the inner channel wall. This configuration places the electrodes far from each other physically in order to avoid shorting and arcing. Moreover, the emissive electrode can provide electrons for the ionization region, allowing for the employment of a somewhat larger magnetic field. The cathode-side electrode is non-emissive, for which better sputter-resistant materials can be found. Also, such a configuration minimizes the deposition of the sputtered material from the electrodes on the channel wall, which may lead to electrical breakdown. The cathode-side electrode can be flat with the channel wall or placed in a groove to protect it from sputtering. Small circular groves can be on the opposite inner wall to avoid shorting between the low-voltage electrode and the high-voltage electrode. In addition, the wall opposite to each electrode can be made from ceramic material adsorbing the sputtering metal, thereby to avoid shorting. We further disclose that greater ionization may be achieved in some thruster regimes when the anode-side segmented electrode protrudes somewhat into the thruster channel, thereby constricting the plasma flow.
In yet another variation, the cathode-side electrode can be made emissive in order to reduce the potential drop near the fringing magnetic fields, thereby providing acceleration more axially directed. In yet another variation, the anode-side electrode can be made non-emissive in order to employ material more sputter-resistant, particularly in the case that the electrodes protrude significantly into the thruster channel.
As a further preferred embodiment, we disclose that placing said electrodes such that the annular segmented electrode rings of conducting material are positioned somewhat on the cathode-side of the magnetic field maximum, where the magnetic lines of force are somewhat concave, will produce a focusing effect on the accelerated ions. In this case, the segmented electrode pairs, such as 7 a and 7 b of FIG. 2, are employed also to define an abrupt potential drop.
The use of any of these embodiments and variations may be recommended depending on the anticipated parameters of the thruster regime, such as temperature, power, specific impulse, and propellant, as well as the anticipated mission requirements such as longevity, efficiency, and ease of satellite integration.
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An apparatus and method for thrusting plasma, utilizing a Hall thruster with segmented electrodes along the channel, which make the acceleration region as localized as possible. Also disclosed are methods of arranging the electrodes so as to minimize erosion and arcing. Also disclosed are methods of arranging the electrodes so as to produce a substantial reduction in plume divergence. The use of electrodes made of emissive material will reduce the radial potential drop within the channel, further decreasing the plume divergence. Also disclosed is a method of arranging and powering these electrodes so as to provide variable mode operation.
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This is a continuation of application Ser. No. 816,531, filed Jan. 6, 1986, abandoned, which is a division of application Ser. No. 682,046, filed Dec. 14, 1984, now U.S. Pat. No. 4,587,202.
The invention relates to a photoetching process for making surgical needles that has particular applicability to the simultaneous manufacture of large numbers of surgical needles, to a sheet made by said process containing a plurality of surgical needles, and to certain surgical needles that can be made by said process.
BACKGROUND OF THE INVENTION
Surgical needles are made, one at a time, by a multi-step process involving considerable time, labor, and precision machinery. A brief outline of a typical process for making surgical needles is the following:
Stainless steel wire of the appropriate diameter is strightened and cut to the desired length to form a blank. One end of the blank is die-formed and/or ground to produce a cutting edge or point. The other end is either drilled to form a hollow receptacle for a surgical suture, or it is stamped to form a channel for swaging the suture. The point is sharpened, and the needle is bent As a rule, the final steps are a heat treatment to temper the needle, that is, to increase the hardness without imparting brittleness, and a polishing process. After this, sutures are attached to the needles by any of several means. On additional feature of the prior art process for making surgical needles is that the shape of the needle is limited by what can be done to a piece of wire. As will be apparent below, this invention provides a process that can be used to make any shape that can be drawn in two dimensions.
This multi-step process is acceptable for the production of relatively large surgical needles but with the advent of microsurgery and the need for ever smaller surgical needles, the process has proven to be quite inefficient for the production of small needles having diameters of, e.g., from one to three mils because of the large amount of skilled labor and precision machinery required in handling such small needles individually throughout the various steps of the process leading to attachment of sutures and final inspection.
This invention provides a process that is particularly well adapted to the efficient simultaneous production of large numbers of small size surgical needles.
BRIEF SUMMARY OF THE INVENTION
The process of the invention comprises the steps of:
(a) coating at least one side of a metal sheet with a light sensitive photoresist;
(b) exposing the photoresist with light in the image of a plurality of surgical needles (the dimensions of the image are modified to compensate for lateral etching during the etching step, as will be explained below);
(c) removing the unexposed photoresist, to thereby leave in place on the metal sheet hardened photoresist in the image of a plurality of surgical needles;
(d) exposing the product of step (c) to an etchant to remove metal not protected by said hardened photoresist, to thereby form a plurality of surgical needles.
The invention also provides a metal sheet containing a plurality of surgical needles.
THE PRIOR ART
Heath, in U.S. Pat. No. 2,735,763, discloses a photoetching process for making small parts from a sheet of thin metal which will not withstand any mechanical working.
Jacks et al., in U.S. Pat. No. 3,358,363, discloses a photoetching process for making fuse elements.
Snyder, in U.S. Pat. No. 3,816,273, discloses a photoetching process for making wire.
Poler, in U.S. Pat. No. 4,080,709, discloses a photoetching process for making the mounting structure for an intra-ocular lens.
Dinardo, in U.S. Pat. No. 4,282,311, and James, in U.S. Pat. No. 4,284,712, disclose a photoetching process for making flyleads for video disc styli.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plane view of a metal sheet containing a plurality of surgical needles produced by the process of the invention;
FIG. 2 is an enlargement of a portion of the sheet of FIG. 1;
FIG. 3 is an enlarged perspective view of a surgical needle made by the process of the invention;
FIG. 4 is a perspective view of the needle of FIG. 3 attached to a surgical suture;
FIG. 5 is an enlarged plan view of a photomask of the image of a single surgical needle that can be used in carrying out the process of the invention;
FIG. 6 is an enlarged plan view of a second photomask of the image of a single surgical needle that can be used in carrying out the process of the invention;
FIG. 7 is an enlarged view of a portion of FIG. 5;
FIG. 8 is an enlarged perspective view of the suture attachment end of the needle of FIG. 3;
FIG. 9 is a cross-sectional view taken along line 9--9 of FIG. 8, and additionally showing a suture attached to the needle;
FIG. 10 is an enlarged view of a portion of FIG. 2;
FIG. 11 is a cross-sectional elevation taken along line 11--11 of FIG. 10; and
FIG. 12 is an enlargement of a portion of FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION
The first step in the process of the invention is to coat at least one side of a metal sheet with a light sensitive photoresist material. The metal that is used can be selected so as to possess all of the strength, hardness, toughness, and grain structure, in the sheet form that the metal will need in the form of a surgical needle. This is one advantage over the current multi-step process for producing surgical needles, in which one step is usually a heat treatment step to develop optimum properties. Any metal or alloy that can be obtained in thin sheet form can be used, provided that it has the requisite properties of strength, hardness, etc. For instance, a tensile strength of at least about 300,000 psi, a Rockwell C hardness of at least 45, and ductility so that the needle can be bent up to about 90° and then straightened without breaking, are desirable. The metals that can be used include stainless steel, specifically, 320 stainless steel and Gin 5 and Gin 6 razor blade grade stainless steel, and molybdenum. Gin 6 stainless steel is preferred. The metal sheet will usually have a thickness of from about one to about ten mils.
The photoresist compositions used are known in the art. For instance, they are discussed in "Photo-Resist Materials and Processes" by William DeForest, McGraw-Hill 1975, and a wide variety of photoresist compositions are available commercially. The metal sheet can be coated with the photoresist by any convenient method, such as dip coating, spraying, and the like. In a preferred aspect of the invention, both sides of the sheet are coated with the photoresist and the needle images are formed on both sides. (In any event, the second side must be coated with either a photoresist or a protective coating.) In a typical coating process, the metal sheet is thoroughly cleaned, rinsed, dipped in dilute aqueous acid, e.g., 10% HC1, rinsed again, dried, and then coated. Since the photoresist compositions are sensitive to light, the coating should be carried out under "safe light" conditions, e.g., under yellow or orange light, or in the dark. After coating, the coated metal sheet is baked at a moderately elevated temperature for a few minutes, e.g., at about 80° C. for about 10 minutes, to dry the coating. After the coated sheet has cooled, it is then exposed to light in the image of a plurality of surgical needles, shaped to compensate for lateral etching of metal during the etching step, a principle that is well understood in the art. This is done by first covering the coated sheet with a negative or first photomask containing an image of the needles. An illustrative enlarged negative or first photomask of a single surgical needle is shown as 14 in FIG. 5 (it will be discussed in more detail) below. In a preferred aspect of the invention, the coated reverse side of the metal sheet is then covered with a second photomask that is the mirror image of the first photomask 14 and in perfect register therewith, and then exposed to light. An illustrative enlarged second photomask of a single surgical needle is shown as 16 in FIG. 6. As will be explained in more detail below, the said second photomask 16 may differ in certain details from the said first photomask 14. The light source used to expose the photoresist is rich in ultraviolet radiation. A carbon-arc light is preferred, but mercury-vapor lamps or ultraviolet rich fluorescent lights may also be used. Typical exposure times are within the range of a few seconds to several minutes, depending upon the nature and power of the light source, the distance of the light from the photoresist, and the sensitivity of the photoresist. The instructions of the manufacturer of the photoresist should be followed in this respect.
After exposure, the photoresist is rinsed in a suitable commercially available "developer" formulated for the particular photoresist being used, to remove the unexposed photoresist. After rinsing, the sheet with the photoresist coating in the form of surgical needles may be baked at, e.g., 120° to 260° C. for 5 to 10 minutes to further harden the remaining photoresist coating. The next step is to etch away the unwanted metal in an etching solution. Typical etching solutions include 36- to 42- degres Baume aqueous ferric chloride, an aqueous mixture of ferric chloride and HCl, or a mixture of aqueous hydrocholoric acid and nitric acid, or the like. Such etching solutions are known in the art, as is their use in a photoetching process. After the etching step, there remains the desired surgical needles, which are removed from the etching solution, washed, and dried. The developed and hardened photoresist is then removed by dissolving away with a suitable commercially available stripper formulated for the photoresist being used. A detailed discussion of the application of the above process to a specific surgical needle design follows.
A surgical needle to be produced by the process of the invention is shown as 12 in FIG. 3. The needle includes a shank 18, a point 20, and a suture attachment end 22. In this design, the suture attachment end 22 includes a channel 24 by which a suture 26 may be attached, as is explained in more detail below. The first step in using the process of the invention to produce this needle 12 is to make a precision black drawing of the needle 12 several hundred times larger than the required finished size. This drawing is then optically reduced to the required size, and an exposure is made near the corner of a sheet of high resolution film. The film is moved laterally by a precision stepping device and a second exposure is made. This is repeated until a row of exposures across the film is completed. The stepping device moves the film upward by one row's width, and a second row of exposures is made. This process is repeated until the entire film area is covered. The film is then developed to produce a negative or photomask of the images of the needles.
FIG. 1 shows a sheet 28 containing a plurality of surgical needles 12 attached at their suture attachment ends 22 to continuous base rows 30 that extend the width of the sheet 28. An enlargement of a portion of the sheet 28 showing one needle 12 is shown in FIG. 2. An enlargement of a photomask 14 corresponding to this needle 12 is shown in FIG. 5. The dimensions of the image 12a of the needle in the photomask are modified to allow for lateral etching of the metal during the etching step. The photomask image of a particular part will be referred to by the same reference number, with the addition of an "a" to the number. Thus, the photomask image of the needle 12 is referred to by the reference number 12a.
As a first approximation, the metal will be etched laterally about the same distance as vertically. Thus, in the preferred situation wherein the metal sheet is etched from both sides, lateral undercutting equal to approximately one-half the thickness of the sheet should be allowed for in the photomask. The image 20a of the needle's point in the photomask preferably does not come to a point, but rather is preferably blunted as is shown in FIG. 5. Lateral etching will cause a point to be formed. This is shown schematically in FIG. 7, which is an enlargement of the image 20a of the needle's point. The arrows show the direction of lateral etching of the metal so that, after the etching step, the point of the needle will have the configuration shown in dashed lines in FIG. 7. (If the needle's point were pointed in the photomask, after etching, the point would probably be rounded rather than sharply pointed, as a result of the lateral etching.)
For ease of handling the needles produced by the process of the invention, it is preferred to produce the needles such that they are attached by a breakable connection to the metal sheet from which they are etched. By so doing, the needles can be kept separated and in order until they are ready for further processing. One way to do this is illustrated in the drawings (see, especially, FIGS. 1, 2, 5, and 6). The sheet 28 shown in FIG. 1 has the needles 12 attached to base rows 30 that extend all the way across the sheet. To assist in the removal of the individual needles 12 from the base rows 30, a transverse groove 32 may be made at the point of attachment of the needle 12 to the base row 30. (See FIGS. 10, 11 and 12.) In the photomask 14, the groove 32 is provided for by a transverse line 32a, in one of the two photomasks only, at the point of attachment to the base row 30a.
Referring now to FIGS. 5, 6, 8, and 9, the suture attachment end 22 includes a channel 24 for use in attaching the needle to a suture 26. In the embodiment shown, the channel 24 is a bilevel channel in which the first half 34 of the channel is offset longitudinally from the second half 36, as is shown clearly in FIGS. 8 and 9. The two halves of the channel are etched equally from both sides of the metal sheet so that each has a depth of about one half the thickness of the sheet. Where the two halves 34, 36 overlap, a hole 38 is produced so that the two halves 34, 36 communicate with each other. A suture 26 is attached by filling both halves 34, 36 with an adhesive material (not shown) such as an epoxy glue while the second half 36 is lying on a flat surface, and then inserting the end of a suture 26 through the hole 38 between the two halves, 34, 36 as is shown in FIG. 9. The epoxy resin is hardened at room temperature, and then given a final cure in an oven at moderately elevated temperatures, such as 40° to 60° C. The photomask images 34a, 36a, of the two halves of the channel are thin lines, as is shown in FIGS. 5 and 6, to allow for the lateral etching that will occur during the etching process. The "bilevel" channel decribed here has several advantageous properties. First, it serves to hold the suture securely in place while the adhesive sets, and, second, it helps to prevent the suture from being pulled out of the channel by a lateral force.
The needles 12 may be detached from the sheet 28 before attaching to a suture 26. This can be done by grasping a single needle 12 with forceps and flexing it at the breakoff groove 32. Alternatively, all needles in a single row can be detached simultaneously by cutting both ends of the base row 30, removing it from the sheet 28, and then pressing the row of needles lightly on to an adhesive surface. Flexing the base row 30 upwards will cause it to break off at the break-off grooves 32, leaving the needles precisley spaced and securely held on the adhesive surface in an ideal position for suture attachment.
After the etching step and after removal of the hardened photosist, if desired, entire sheets of needles may be electropolished using conventional electropolishing methods to smooth off rough edges, polish the surfaces, and improve the shape of the needle points by reducing or eliminating undesirable projections, and by sharpening the edge. This is another advantage of the invention, since hundreds, and perhaps thousands, of needles can be electropolished simultaneously in a few minutes.
A typical electropolishing bath is an aqueous sulfuric, phosphoric, and glycolic acid bath. Polishing times of about 30 seconds at ten volts and 90° C. are typical.
The invention has been described and claimed in terms of a dry positive photoresist technique, that is, the hardened photoresist on the metal sheet is in the image of the part that is to be made. It is theoretically possible to use a wet photoresist or a negative photoresist technique in carrying out the process of the invention, although to do so would be awkward and uneconomical.
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Surgical needles are produced by a process which comprises the steps of:
(a) coating at least one side of a metal sheet with a light sensitive photoresist;
(b) exposing the photoresist with light in the image of a plurality of surgical needles, each needle having a pointed end and a suture attachment end;
(c) removing the unexposed photoresist, to thereby leave in place on the metal sheet hardened photoresist in the image of a plurality of surgical needles;
(d) exposing the product of step (c) to an etchant to remove metal not protected by said hardened photoresist, to thereby form a plurality of surgical needles.
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This application claims the benefit of U.S. Provisional Patent Application No. 60/731,095 filed on Oct. 28, 2005.
FIELD OF THE INVENTION
This invention relates generally to the field of hydrocarbon exploration and production, and more particularly to hydrocarbon system analysis. Specifically, the invention is a method for predicting total hydrocarbon column height and contacts in a hydrocarbon trap.
BACKGROUND OF THE INVENTION
Oil and gas deposits tend to occur in geological configurations called traps. Buoyant forces support an oil layer on top of the denser ground water, and similarly a gas layer floats on top of the oil layer. A trap is a geologic configuration that “seals” the hydrocarbon columns in place, preventing their escape. Such escape could result either from fracture of the seal due to hydrocarbon pressure or by capillary seepage through the seal. Such traps often contain commercial deposits of oil or gas. In evaluating such a trap, whether a prospect trap in the course of exploration or a trap of interest in the course of field development, the depths of the gas/oil contact and the oil/water contact are key quantities of interest. These contact depths will depend significantly on the seal capacity, i.e. the ability of the seal to resist fracturing and capillary seepage.
Understanding and predicting total hydrocarbon column height (difference in depth between the hydrocarbon-water contact and the top of the hydrocarbon column) and contacts in a hydrocarbon trap occupies the attention of every hydrocarbon exploration or production company. Seal capacity, which is the maximum hydrocarbon column height a seal can hold before leaking, is typically evaluated on a deterministic basis with little consideration of the substantial uncertainty associated with input parameters. Furthermore, the seal is typically evaluated for either mechanical seal capacity or capillary seal capacity without considering both simultaneously. Also, seal capillary entry pressure, the requisite input parameter for capillary seal capacity analysis, is usually directly measured by mercury injection capillary capacity tests on small pieces of rock. Results from these tests are not readily available everywhere, nor are they necessarily representative of adjacent rocks in the seal.
SUMMARY OF THE INVENTION
In one embodiment, the invention is a method for evaluating seal capacity in order to determine hydrocarbon column heights (and optionally associated probable errors) for a subject hydrocarbon trap containing oil, gas, or both oil and gas, said method comprising: (a) estimating a probability-weighted distribution for capillary entry pressure values at one or more calibration locations by equating capillary entry pressure with hydrocarbon buoyancy estimated through inversion of pressure data and trap geometry; (b) estimating a probability-weighted distribution for hydraulic fracture pressure values from calculations using theoretical calculation or from empirical data collected from one or more calibration locations; (c) obtaining probability-weighted distributions for anticipated fluid properties and trap geometry parameters at the subject hydrocarbon trap, said properties and parameters including:
(1) in-situ fluid (gas, oil, and brine) density;
(2) reservoir pressure;
(3) reservoir temperature;
(4) trap geometry, including crest and spill depths;
(d) determining a current realization value for each of the fluid properties and trap geometry parameters of the subject trap by randomly selecting from their respective probability-weighted distributions; (e) determining a current realization value for the subject trap's capillary entry pressure by: randomly selecting a capillary entry pressure value from the probability-weighted distribution determined for the one or more calibration locations; and adjusting the selected capillary entry pressure value by calculating interfacial tensions consistent with the subject hydrocarbon trap's pressure, temperature, and fluid composition selected for the current realization; (f) determining a current realization value for the subject trap's hydraulic fracture pressure by: randomly selecting a hydraulic fracture pressure value from the probability-weighted distribution determined by calculation or empirical data from one or more calibration locations; and adjusting the selected hydraulic fracture pressure value consistent with the trap crest depth selected for the current realization, thereby generating an adjusted fracture pressure gradient; (g) calculating a column height for each hydrocarbon phase (oil and gas) present in the subject trap using the randomly selected fluid properties and trap geometry parameters of the subject trap for the current realization, said calculation equating hydrocarbon buoyancy with total seal capacity, said total seal capacity being obtained by combining the adjusted hydraulic fracture pressure gradient and capillary entry pressure values determined for the current realization; (h) repeating steps (d)-(g) a predetermined number of times; and (i) averaging the results and optionally calculating an uncertainty for each column height from spread within the results.
In one embodiment of the invention, the step above of estimating a probability-weighted distribution for capillary entry pressure values at a calibration location comprises: (a) obtaining probability-weighted distributions for fluid properties and trap geometry parameters at the calibration location; (b) randomly selecting a current realization value for each said fluid property and trap geometry parameter from their probability-weighted distributions; (c) estimating gas entry pressure (GEP) from hydrocarbon column buoyancy using the current realization values of the fluid properties and trap geometry parameters; (d) optionally estimating implied mercury injection capillary pressure (MICP) using the current realization values of the fluid properties and trap geometry parameters and by calculating brine-gas interfacial tensions; (e) calculating oil entry pressure (OEP) from the gas entry pressure; and (f) repeating steps (b)-(e) a pre-selected number of times, averaging the results and estimating a probability-weighted distribution for GEP, OEP and, optionally, MICP.
In some embodiments of the invention, the theoretical calculation for estimating a probability-weighted distribution for hydraulic fracture pressure values uses critical-state soil mechanics to solve a minimum stress equation in which hydraulic fracture pressure is approximated by minimum horizontal stress.
The invention's method for determining capillary entry pressure may be used by itself in a deterministic calculation of capillary entry pressure for a hydrocarbon trap from hydrocarbon contact depths and fluid densities, the capillary entry pressure being specified by a gas entry pressure, an oil entry pressure and, optionally, a mercury-injection capillary pressure, the method comprising: (a) estimating gas entry pressure from groundwater aquifer buoyancy pressure on the hydrocarbon trap's hydrocarbon column, said buoyancy pressure being determined from the hydrocarbon contact depths and fluid densities; (b) calculating interfacial tension for a gas-water interface and for an oil water interface and, optionally, for a mercury-air interface, said interfacial tensions being calculated for conditions representative of the trap and its fluids; and (c) calculating oil entry pressure and, optionally, mercury-injection capillary pressure from the gas entry pressure and the interfacial tensions. In some embodiments, the buoyancy of the hydrocarbon column which is needed in the course of estimating gas entry pressure step is determined by steps comprising: (a) obtaining hydrocarbon depth and fluid density data from a measured interval (calibration location); (b) developing a black oil empirical model of hydrocarbon fluid properties; (c) selecting an aquifer composition model and gas equation of state that may be used to correct aquifer and gas densities for variations in pressure and temperature; (d) adjusting input parameters of the black oil model and the aquifer composition model to match measured in situ well bore fluid densities; (e) adjusting fluid gradients as a function of pressure and temperature within the trap using the said models to extrapolate away from the measured interval to the trap, yielding hydrocarbon and aquifer depth vs. pressure curves at the trap's structural crest; and (f) deducing hydrocarbon buoyancy pressure from differences between the aquifer depth-pressure curve and the hydrocarbon depth-pressure curve.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention and its advantages will be better understood by referring to the following detailed description and the attached drawings in which:
FIG. 1 illustrates that hydrostatic pressure depends only on depth and fluid density and is independent of container shape;
FIG. 2 illustrates the meaning of typical terms used to describe subsurface pressures;
FIG. 3 illustrates that low hydrocarbon density relative to water creates a slower decrease in pressure with shallowing depth within hydrocarbon columns;
FIG. 4 illustrates capillary wetting angle in a pore throat;
FIGS. 5A-F depict various possible cases of contact and capillary/mechanical leakage relationships;
FIG. 6 is a flowchart showing basic steps of one embodiment of the present inventive method;
FIG. 7 is a flowchart of basic steps in one embodiment of the present invention's method for estimating a probability-weighted distribution for capillary entry pressure;
FIG. 8 illustrates developing a probability-weighted distribution for a parameter (fracture pressure) from empirical data; and
FIG. 9 illustrates developing a probability-weighted distribution for the parameter fracture pressure from a theoretical fracture pressure model.
The invention will be described in connection with its preferred embodiments. However, to the extent that the following detailed description is specific to a particular embodiment or a particular use of the invention, this is intended to be illustrative only, and is not to be construed as limiting the scope of the invention. On the contrary, it is intended to cover all alternatives, modifications and equivalents that may be included within the spirit and scope of the invention, as defined by the appended claims.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is a method for predicting mechanical and capillary seal capacity in tandem, and propagating input parameter uncertainties to predict the probable error of the result. The present invention also discloses a method for predicting top-seal capillary entry pressure based on inversion of readily observed trap and hydrocarbon column-height parameters combined with fluid gradients estimated from commonly available fluid and physical properties data.
The present invention recognizes that predictions of total hydrocarbon column height and contacts in a hydrocarbon trap require combined evaluation of capillary and mechanical seal properties, careful evaluation and quantification of uncertainties, and the propagation of these uncertainties through the analysis. It is a premise of the present invention that a seal should be evaluated for mechanical seal capacity and capillary seal capacity simultaneously, and that this is a requirement for robust hydrocarbon column height and fluid contact predictions.
In the present inventive method, attention is focused on trap-scale controls on hydrocarbon contacts. Accordingly, hydrocarbon contact predictions are sensitive to trap geometry (including sand connectivity resulting from structural and stratigraphic controls) and hydrocarbon-leak potential. The present inventive method is concerned with the evaluation of hydrocarbon leakage from a trap with a known geometry. It may be effectively used as a tool to help quickly evaluate trap geometry and connectivity scenarios, propagating uncertainty through statistical calculations. It is thus appropriate to use the present inventive method to, among other applications, evaluate the validity of hydrocarbon contacts for trap geometry scenarios, explore the consequences of direct hydrocarbon indicators or proposed pre-drill fluid contacts, or to calculate implied seal capacities in reservoirs in which the contacts and trap geometry are fairly well constrained. Following is a brief review of the theoretical basis of the present inventive method.
Fluid Pressure
A complete description of subsurface hydrodynamics is not presented because this depth of detail will be known or readily available to persons skilled in the art from familiarity with references such as two articles by Chapman in Studies in Abnormal Pressure , Fertl, W. H., Chapman, R. E. and Holz, R. F., Eds., Elsevier, Amsterdam, Developments in Petroleum Science 38 (1994): “The Geology of Abnormal Pore Pressures,” 19-49; and “Abnormal pore pressures: Essential theory, possible causes, and sliding,” 51-91. A few key fundamental concepts and definitions are helpful for the discussion that follows. Normal or hydrostatic pressure is defined as the pressure exerted by a static column of water from the surface to the depth of interest. FIG. 1 illustrates that such pressure depends only on vertical depth (and fluid density) regardless of the shape of the container. The rate of change of pressure with depth, or pressure gradient, is a function of the fluid density. In the case of subsurface brines, hydrostatic pressure gradients range between 0.42 and 0.47 psi/ft depending on brine salinity and pressure (as brine is slightly compressible).
The pressure at any depth resulting from the weight of the overlying sediments is termed the lithostatic or overburden pressure or stress. Typical lithostatic pressure gradients range between 0.7-1.2 psi/ft. In a hydrostatic system, the overburden stress is transmitted by the grain-grain contacts in the sediments and the hydrostatic stress is transmitted by the brine within the interconnected pore network. The overburden stress causes the sediment to compact, collapsing the pore network and expelling brine from the pore space. In low permeability sediments, brine expulsion is impeded, so the pore fluid may begin to support some of the overburden stress causing the pore pressure to be elevated above hydrostatic. The portion of the overburden stress supported by the grain-grain contacts in the rock is termed the effective stress and the portion supported by the pore fluid is termed the overpressure (or excess pressure). FIG. 2 is a graph of overburden stress 21 relative to hydrostatic (normal) pressure 22 . Pore pressure is indicated by 23 . Thus, effective stress 24 and overpressure (excess pressure) 25 may be read from the graph.
Practically, pore pressures approach a mechanical limit somewhat less than the lithostatic pressure or stress (σ L ) called the fracture pressure (P f ), or the fluid pressure at which hydrofractures begin to form in a rock. This can be seen in FIG. 2 . The magnitude by which σ L exceeds P f depends on the orientation of maximum compressive stress (σ 1 ). In extensional or quiescent environments, σ L =σ 1 and P f =σ L , whereas in contractional settings, σ L ≠σ 1 and P f ≈σ L .
It is important to recognize that over-pressured systems are dynamic and high overpressure means a high potential for brine flow. The magnitude of the pore pressure will depend on the burial rate (increasing the overburden stress), the stratigraphy, and the rate of brine expulsion. So systems with a high burial rate and/or a low permeability will tend to generate higher excess pressures and lower effective stresses.
In multiphase fluid systems, density differences between phases lead to buoyant segregation of fluid phases ( FIG. 3 ). In hydrocarbon systems, hydrocarbon liquids and gases, being less dense than formation brines, will have a lower pressure gradient and higher absolute pressures than the aquifer. This pressure difference is a function of the hydrocarbon density and column height (the vertical height of the different hydrocarbon fluid phases in the trap) and is the measure of the fluid potential for secondary hydrocarbon migration. Typical hydrocarbon pressure gradients are ˜0.3 psi/ft for oil and ˜0.1 psi/ft for gas. In FIG. 3 , the oil-water cutoff (interface) is 31 and the gas-oil cutoff is 32 . Line 33 shows the more gradual decline in pressure with decreasing depth within the hydrocarbon column 36 as compared to a hypothetical water column represented by line 35 which represents hydrostatic pressure alone, and line 34 which shows the increased pressure, called overpressure 37 , due to the weight of the overburden. Line 38 denotes the buoyant pressure. The pressure gradient in each medium is the slope of the respective pressure vs. depth line.
Mechanical Seal Capacity
Mechanical seal capacity refers to the size of the hydrocarbon column that achieves a hydraulic pressure at the top of column equaling or exceeding the hydraulic fracture pressure of the overlying seal. At mechanical seal capacity hydrocarbons migrate through the seal at the top of column. A complete description of subsurface mechanical seal capacity is not presented because this depth of detail will be known or readily available to persons skilled in the art. For a description of rock fracture mechanics models, see, for example, Simmons and Rau, “Predicting Deepwater Fracture Pressures: A Proposal,” paper SPE 18025, 1988 SPE Annual Technical Conference and Exhibition, Houston, Oct. 2-5; or Rocha and Bourgoyne, “A new simple method to estimate fracture pressure gradient,” Pore pressure and fracture gradients [Serial] SPE Reprint Series, 101-107 (1999). Following are a few key fundamental concepts and definitions.
Hydraulic seal failure is typically associated with three geologic environments:
Shallow reservoirs Highly over pressured reservoirs Very large hydrocarbon columns
The key parameter controlling hydraulic seal failure is the minimum effective stress. The effective stress is defined as the difference between the minimum principal compressive stress and the pore fluid pressure. The minimum compressive stress is commonly horizontal, but can be oriented in different directions depending on the geologic environment. Hydraulic seal failure occurs when the effective stress in a particular portion of the stratigraphic section approaches zero (approaches a tensile regime). The vertical compressive stress (due to overburden) always increases with depth in sedimentary basins, but the effective stress may increase or decrease with depth due to other factors.
At low effective stress, small disturbances in the stress field can hydraulically fracture or re-open fractures in the top seal and result in hydrocarbon leakage. The increase in fluid pressure caused by hydrocarbon migration into a trap can be enough to fracture the top or fault seal. When fracturing occurs, hydrocarbons will leak from the trap until the fluid pressure drops below the minimum principal compressive stress, which then allows the fractures to close and the leakage to cease. In general, hydraulic top or fault seal failure is not catastrophic, and the traps do not lose all hydrocarbons.
To evaluate hydraulic leakage risks, some measure of hydrocarbon column height, hydrocarbon density, aquifer pressure, and fracture pressure is required. There are several methods for estimating fracture pressure, or fracture gradient, including:
Minimum Stress Methods: these are commonly used methods in which the fracture pressure is approximated by the minimum horizontal stress (σ h min ). Minimum stress methods assume stable relationships between horizontal and vertical stresses that depend on rock properties; During burial and compaction of sediments (during which vertical effective stress at maximum value):
σ h min =k o (σ 1 −P pore )+ P pore =k o σ eff +P pore
where
σ h min =the minimum horizontal stress,
k o = σ 3 - P pore σ 1 - P pore
(for a uniaxial compressive state where compaction is in one direction with no lateral strains)=ratio of minimum and maximum effective stress, 0.4 for strong materials to >0.8 for shale/clay,
σ 1 =the vertical stress, taken as the sediment overburden pressure at the depth of interest, and
P pore =pore pressure.
Hoop Stress Methods: these methods are based on analytical solutions for stresses in a plate with a circular hole (e.g., a wellbore). They predict lost returns when the wellbore pressure causes the hoop stress along the wellbore wall (or the stress tangential to the wellbore) to equal the rock's tensile strength. Fracture Mechanics Methods: these methods take detailed information about fracture toughness, initial crack length, and fluid pressure distribution along a crack, and use that information to determine the conditions under which fracture propagation will begin and end. They are used to design hydraulic fracturing treatments. Empirical methods: Minimum horizontal stress is sometimes approximated by a best-fit to empirical measures of the compressive stress (formation integrity test, FIT; leak-off test, LOT; pressure integrity test, PIT; or production data).
In complex tectonic environments, detailed estimation of fracture gradient may require application of multiple approaches. In many settings, however, a minimum horizontal stress method provides adequate estimates, and its required input parameters are commonly available. Therefore, it is one of the two fracture gradient estimation methods, along with empirical approaches, that are used in preferred embodiments of this invention, as described in detail below.
Capillary Seal Capacity
A complete description of subsurface capillary seal capacity is not presented (except for innovations of the present invention) because this depth of detail will be known or readily available to persons skilled in the art. Following are a few key fundamental concepts and definitions.
Hydrocarbons move through water-saturated porous rocks due to buoyancy. Work is required to increase the surface area of a hydrocarbon filament so it can displace water in the pore space of finer-grained rocks. This results in a resistance to hydrocarbon movement. The magnitude of this resistance is a function of the size of the smallest pore throat in the connected pathway, wettability, and the interfacial tension between hydrocarbon and brine. See, for example, Berg, R. R., “Capillary pressure in stratigraphic traps,” AAPG Bulletin 59, 939-956 (1975); and Schowalter, T. T., “Mechanics of secondary hydrocarbon migration and entrapment,” AAPG Bulletin 63, 723-760 (1979). The “capillary entry pressure” (Pc), also called the “displacement” or “threshold” pressure, quantifies the magnitude of the resistant force for low flow rates. See, for example, Smith, D. A., “Theoretical considerations of sealing and non-sealing faults,” AAPG Bulletin 50, 363-374 (1966).
The relevant physics is depicted in FIG. 4 . Small pore throats 41 within the finer-grained sealing unit 42 impede hydrocarbon flow so that the underlying hydrocarbon column 43 increases. As the hydrocarbon column increases, the buoyancy of the hydrocarbon column increases the pressure difference between the wetting and non-wetting phase, forcing the hydrocarbons into the water-saturated pore throat. The equilibrium hydrocarbon-brine-solid contact is at the wetting angle. When the hydrocarbon column height is sufficient for the buoyancy force to equal the capillary entry pressure of the seal, hydrocarbons may enter the pore throat 41 , deforming the immiscible boundary between the phases into a shape that fits between the pore throats of the sealing unit.
When two immiscible fluids contact a solid surface, one phase is preferentially attracted to the sold. Wettability is expressed mathematically by the contact angle (wetting angle) of the oil-water interface against the rock. This angle depends on the degree of preferential attraction or, put another way, the work needed to separate a wetting fluid from a solid. In some embodiments of the present invention, it is assumed that rock grains in natural systems are water wet, meaning that grains are coated by a thin water film.
Interfacial tension is an expression of the work required to enlarge by unit area the interface between two immiscible fluids. This tension results from the difference between the mutual attraction of like molecules within each fluid and the attraction of dissimilar molecules across the fluid interface.
The upward pressure P c resulting from the buoyancy force on the hydrocarbons is given by
P c . = 2 η cos θ R
where η is the hydrocarbon-water interfacial tension, θ is the wetting angle at breakthrough, and R is the pore throat radius.
Model for Prediction of Contact Elevations
Trap configuration combined with capillary entry pressure and hydraulic fracture gradient is sufficient to determine the location of present-day hydrocarbon contacts if various assumptions including the following are satisfied:
(a) The present-day “geology” (geometry, rock properties, etc) is sufficient to solve the problem. This implies that the charge rates are generally high compared to deposition rates. This assumption is not always valid, but experience indicates that this assumption usually does not lead to significant errors. This assumption is most likely to be valid for old traps and/or systems with recent hydrocarbon charge. (b) Volumes of oil and gas sufficient to fill the accumulation have been generated from the source and migrated to the trap (i.e., the trap is not charge-limited for oil or gas). (c) The hydrocarbon distribution is at a quasi steady-state equilibrium condition. According to this assumption, migration is fast on a geological time scale and the final hydrocarbon distribution is not a function of the total charge volume (except that the trap is not charge limited as stated above). The distribution of fluids is controlled by capillary forces and is independent of the permeability. (Capillary forces and permeability are not totally independent, but in this model only the capillary forces are needed.) This assumption means that at present day, the charge rate of fluids into the trap is equal to the sum of the leakage and spillage rates from the trap. (d) Capillary leakage occurs at the point of highest buoyancy force for the leaking phase. (If a trap leaks gas, it leaks at the crest; if a trap leaks oil, it leaks at the gas-oil contact.) This has the same effect as the slightly more restrictive assumption that the seal has uniform capillary properties. (e) Hydraulic fracture leakage occurs at the top of the hydrocarbon column (trap crest). (f) The capillary (entry) pressure of the seal is not a function of fluid saturations in the seal or the flux rate of fluids through the seal. The seal capillary capacity changes only due to changes in brine-hydrocarbon interfacial tension. This assumption means the hydrocarbon distribution is not a function of the system charge rate. (g) The contact angle is zero for oil-water and gas-water systems (i.e., seals are completely water wet). (h) The water phases in the seal and the trap have similar excess pressures. Higher excess pressures in the seal increase the effective seal capacity because the buoyancy force of the hydrocarbon column must exceed the excess pressure as well as the capillary entry pressure. Lower excess pressures in the seal decrease effective seal properties by providing an additional driving force for hydrocarbon movement. See, for example, Heum, O. R., “A fluid dynamic classification of hydrocarbon entrapment,” Petroleum Geoscience 2, 145-158 (1996).
If the hydrocarbons are in the two-phase region (in P-T space) and given the above assumptions, there are six possible leakage scenarios. These six cases are illustrated in FIGS. 5A-F . In the vernacular of the Sales classification system, Case 6 ( FIG. 5F ) is equivalent to a Sales Class 1 trap, Case 4 ( FIG. 5D ) is equivalent to a Sales Class 2 trap, and Case 2 ( FIG. 5B ) is equivalent to a Sales Class 3 trap. Case 1 ( FIG. 5A ) is not possible to realize with capillary leakage alone, so there is no equivalent in the Sales classification system. See Sales, J. K., “Seal strength vs. trap closure—A fundamental control on the distribution of oil and gas,” in, Seals, Traps, and the Petroleum System , R. C. Surdam, ed., AAPG Memoir 67, 57-83 (1997). Cases 2 and 3 ( FIG. 5C ) and Cases 4 and 5 ( FIG. 5E ) are not possible to distinguish with hydrocarbon column heights alone.
FIGS. 5 A-F are similar in what they show to FIG. 3 . Each drawing has one line showing water pressure vs. depth and a second line showing the more gradual increase of pressure with depth in the hydrocarbon column. Where the hydrocarbon column includes both gas and oil phases, the second line consists of two line segments with different slopes. ( FIGS. 5 B, C, D and E) In FIG. 5A , the hydrocarbon column is all oil (narrow stripes) and in FIG. 5F it is all gas (wide stripes).
In case 1 ( FIG. 5A ), the buoyancy pressure of the hydrocarbon column exceeds the seal fracture pressure. Both oil and gas leak at the crest by hydraulic fracturing and trap completely filled with oil. In the limit where the aquifer pressure at the crest approaches the fracture pressure (P f ), the oil column height approaches zero.
In case 2 ( FIG. 5B ), the buoyancy pressure of hydrocarbon column exceeds the gas entry pressure (“GEP”) at the crest and the buoyancy of the oil leg exceeds the oil entry pressure (“OEP”) at the gas-oil contact (“GOC”). Gas and oil leak by capillary breakthrough separately at the crest and at the elevation of the GOC.
In case 3 ( FIG. 5C ), the buoyancy pressure of the hydrocarbon column exceeds the P f at the crest and the buoyancy of the oil leg exceeds the OEP at the GOC. Gas hydraulic leakage occurs at the crest and oil capillary leakage occurs through the topseal at the elevation of the GOC. Leakoff and the OEP pressure control the GOC and the oil-water contact (“OWC”). The small gas column at the top of the hydrocarbon column in FIGS. 5B and 5C is indicated by 51 .
In case 4 ( FIG. 5D ), the buoyancy pressure of the hydrocarbon column exceeds the GEP at the crest, but the buoyancy of the oil leg does not exceed the OEP at the GOC. Gas capillary leakage occurs at the crest and oil spills from the trap. GEP and closure height control GOC and OWC.
In case 5 ( FIG. 5E ), the buoyancy pressure of the hydrocarbon column exceeds the P f at the crest, but the buoyancy of the oil leg does not exceed the OEP at the GOC. Gas hydraulic leakage occurs at the crest and oil spills from the trap. P f and closure height control the GOC and OWC.
In case 6 ( FIG. 5F ), the buoyancy pressure of an all gas column is less than the P f or the GEP. There is no leakage, both gas and oil spill from the trap, and the only fluid phase within the trap is gas.
Basic Method
FIG. 6 is a flowchart showing basic steps for one embodiment of the present inventive method. First, a brief description of the steps of the method is given, followed by treatments of some steps in more detail.
At step 61 , a probability-weighted distribution is estimated for capillary entry pressure values at a calibration location (as contrasted with the location of the prospect trap that is the subject of the evaluation). Possible alternatives for performing this step include: a) performing standard laboratory Mercury Injection Capillary Entry Pressure (MICP) experiments on a representative sampling of seal rocks from a calibration location, or b) calculating a value for MICP implied by hydrocarbon column heights at a calibration location (this preferred method is described in more detail below).
Step 62 is estimating a probability-weighted distribution of hydraulic fracture pressure values (i.e., a fracture gradient) at a calibration location. Possible alternatives for performing this step include:
(a) Best Fit to Leak-off Test Data. Estimate hydraulic fracture gradient by deriving a best fit to leak-off pressure test data using a linear regression algorithm (described further below). (b) Geomechanical Theory. Estimate the hydraulic fracture gradient using critical-state soil mechanics method incorporating externally derived overburden and pore pressure estimates, and a k o value (lithology dependent horizontal to vertical stress ratio) estimated from regional experience, and/or rock type, and/or burial history (described further below).
Step 63 is estimating a probability-weighted distribution for trap and fluid parameters at a prospect location, most likely based on expert opinion.
(a) Trap parameters (best estimate plus associated uncertainty ranges)
i) Depth of the trap crest ii) Depth of the trap spill and/or controlling fault juxtaposition leaks. iii) Trap temperature
(b) Fluid parameters
i) In-situ fluid (hydrocarbon, brine) density. ii) Formation aquifer pressure
The remaining steps concern the probabilistic analysis, for which the preceding steps provide input. The probabilistic analysis is also discussed in more detail below. Step 64 is randomly selecting from the three probability-weighted distributions from steps 61 - 63 a capillary entry pressure value, a hydraulic fracture pressure value, and a value for each of the trap and fluid properties. The capillary entry pressure is derived from a calibration location where the hydrocarbon contacts are known. In step 65 , the selected capillary entry pressure value is adjusted for interfacial tensions consistent with pressure, temperature, and fluid properties selected to be representative of the subject (prospect or development) trap. In step 66 , the selected hydraulic fracture pressure is adjusted for a selected crest depth believed to be representative of the subject trap. At step 67 , hydrocarbon column heights are calculated consistent with the selected trap parameters, fluid parameters, and mechanical seal capacity parameters. One random realization is now complete. At step 68 , steps 64 - 67 are repeated a predetermined number of times, thus generating the desired number of random realizations. At step 69 , the stochastic results are ready for analysis by the data interpreter.
Estimating Capillary Entry Pressure (Step 61 )
Steps 61 and 62 in the FIG. 6 flowchart call for calculating a probability-weighted distribution of capillary and mechanical seal capacities based upon observations obtained at one or more calibration locations. These distributions are adjusted to conform to expected conditions at a subject location. The following discussion discloses a preferred method for determining the probability-weighted distribution of capillary seal capacity from a calibration location. The method may be repeated several times if multiple calibration locations are available. Favorable calibration locations for capillary seal capacity analysis are preferably selected based upon the following criteria:
(a) The calibration location and the subject location should be in the same geographic area. (b) The components of the trap configuration of the calibration location listed below as required input quantities should be well constrained. (c) The top seal (the rock type through which hydrocarbons leak) of the calibration location should be similar to the subject top seal in terms of lithology, texture, and effective stress.
In the afore-mentioned preferred embodiment of the present inventive method, the seal capillary entry pressure is estimated by inversion of commonly available hydrocarbon trap and fluid property data. This technique is a significant departure from the existing petroleum industry practice of directly measuring capillary-entry pressure by mercury injection (MICP) or other techniques. These existing techniques depend on availability of rock samples that are representative of the weakest element of the seal or comparisons to global databases. The method disclosed herein results in an estimate of seal capillary-entry pressure for the weakest element of the seal without specific identification of that element.
This method extends a model disclosed by Sales for hydrocarbon leakage based on known subsurface fluid contacts, trap parameters, and fluid compositions for application to the exploration scale. See Sales, J. K., “Seal strength vs. trap closure—A fundamental control on the distribution of oil and gas,” in Seals, Traps, and the Petroleum System , R. C. Surdam, ed., AAPG Memoir 67, 57-83 (1997). This empirical model may be used to estimate the capillary seal capacity necessary for hydrocarbon leakage to occur out of a trap with a given closure height (so-called “implied” MICP).
A premise of the present invention's method for estimating capillary seal capacity is that the most reliable estimates of seal capacity are implied values from pressure data. An implied gas entry pressure (GEP) assumes that the GEP is equal to the buoyancy forces of the hydrocarbons in a trap that is leaking gas or gas and oil. If the trap is not leaking, then the calculated value will be a minimum implied GEP instead of a most likely implied GEP.
According to a quasi-steady-state equilibrium model, capillary seal strength is related directly to the buoyancy pressure applied by the hydrocarbon column to the top seal. The buoyancy pressure at the crest is less than the seal capacity for Case 6 traps and equal to the gas entry or threshold pressure for Case 2 or 4 traps (See FIGS. 5A-F ). The buoyancy pressure exerted by the oil column at the gas-oil contact is equal to the oil entry or threshold pressure for Case 2 or 3 traps. The gas or oil entry pressure may be related to the seal capacity if oil-brine and gas-brine interfacial tensions are known.
For gas entry pressure (GEP) estimation in this embodiment of the present inventive method, the following probability-weighted distributions are obtained and used:
depth to the top of the hydrocarbon column (D CTOC ). depth to the gas-oil contact (D CGOC ). depth to the oil-water contact (D COWC ). in-situ gas density (ρ G ). in-situ oil density (ρ O ). in-situ brine density (ρ B ).
For oil entry pressure (OEP) estimation in this embodiment of the present inventive method, the following probability weighted distributions are obtained and used:
reservoir temperature (T CGOC ) at D CGOC . gas pressure (P G CGOC ) at D CGOC . probability-weighted distribution of the Z factor (Z) (See, for example, Standing, M. B. and Katz, D. L., “Density of natural gases,” Trans. AIME 146, 140-149 (1942)).
The flowchart of FIG. 7 shows basic steps for performing step 61 of FIG. 6 for this embodiment of the present inventive method:
Step 71 : Random Selection of Input Parameters
A single value of each required input quantity is randomly selected from the probability-weighted distribution for such parameter to generate the input values for the current realization.
Step 72 : Estimate Gas Entry Pressure (GEP) for Current Realization
The GEP (gas entry pressure) is determined from contact elevations, trap geometry, and pressure gradients alone, and may be used for predictions at sites with similar pressure and temperature (P-T) conditions.
To estimate the buoyancy pressure exerted by trapped hydrocarbons within the structure, a black-oil model (a well known empirical model of hydrocarbon fluid properties) may be used to (1) correct fluid gradients for changes in pressure and temperature away from the measured interval (an untypical application of the black-oil model) and (2) correct measured fluid gradients measured in offset drilling to compensate for changes in temperature and pressure at the prospect of interest (a standard application). An aquifer composition model (salinity) and gas equation of state may be used to correct aquifer and gas densities for variations in pressure and temperature. Non-ideality (in the gas equation of state) is specified by the Z factor, which may be determined iteratively. An alternative method for correcting fluid properties for pressure, temperature, and fluid composition is that of an EOS (Equation of State) model. Such models are readily available to practitioners in the field and they provide one example of an approach that could be used as an alternative to the black oil model methodology developed below or another empirical approach or other method for performing this step.
This preferred embodiment of the invention operates by first manually adjusting input parameters of the black-oil model and aquifer composition model to match measured in-situ fluid densities from the wellbore. Next, the fluid gradients are adjusted as a function of absolute pressure and temperature within the trap using the calibrated models to extrapolate away from the measured interval, i.e. the depth range over which pressure data was collected. The results are curves that may be used to estimate hydrocarbon and aquifer pressure at the structural crest. The difference between the extrapolated aquifer depth-pressure curve and the extrapolated hydrocarbon depth-pressure curve at the crest of the trap is a measure of the buoyancy pressure exerted by the hydrocarbons at the structural crest.
The gas entry pressure at the depth of the top of the hydrocarbon column at the calibration location (D CTOC ) may thus be estimated from the buoyancy of the hydrocarbon column by:
GEP CTOC =ρ B g ( D COWC −D CTOC )−[ρ O g ( D COWC −D CGOC )+ρ G g ( D CGOC −D CTOC )]
The oil entry pressure (“OEP”) may then be calculated from the GEP and hydrocarbon-brine interfacial tension. The MICP may be calculated in a similar way. This calculation requires an estimate of the gas-brine interfacial tension. Interfacial tension is calculated from the Firoozabadi Tau, an empirical relationship between hydrocarbon-brine density difference and interfacial tension:
τ= e (0.091251n(Δρ) 2 −0.538331n(Δρ)+1.227328) ,
where Δρ is the hydrocarbon-brine density difference.
The Firoozabadi Tau may be used to estimate hydrocarbon-brine interfacial tension through the relationship:
η B-HC =[Δρ B-HC ( T pr HC ) −0.3125 τ] 4 ,
where T pr HC is the pseudo-reduced temperature (calculated from the black-oil correlations—see below). In this equation, density is expressed in g/cc, pseudo-reduced temperature is dimensionless, and the interfacial tension is in dynes/cm. The same relationship between variables holds for the interface between any two substances, e.g., mercury and air. The factor τ in the expression for interfacial tension may also be considered to have indices because the density difference Δρ in the expression above for τ refers to the density difference between the particular two fluids for which the interfacial tension is being calculated. Once the hydrocarbon-brine interfacial tension and entry pressure are known, seal capacity may be estimated according the relationship:
M I C P η Hg - air cos θ Hg - air = O E P η B - O cos θ B - O = G E P η B - G cos θ B - G
where
MICP=P Hg −P air , OEP=P o −P w , GEP=P g −P w , and θ ij is the contact angle for i and j fluid system.
Input Data for Some Embodiments of the Present Inventive Method:
Trap parameters (crest depth, spill depth (syncline, fault juxtaposition leak, or thief sand), temperature at crest) Fluid gradients (oil, gas, water gradients from RFT data or derived by technique outlined above) Hydrocarbon column heights or contact depths (e.g., direct hydrocarbon indicators, AVO, well penetrations)
These steps will now be explained in more detail. (Note: the terms water and brine are used interchangeably in the interfacial tension discussions.)
Step 73 : Estimate Implied Mercury-Injection Capillary Pressure (MICP) for Current Realization
(Note: Capillary entry pressure for the seal of a hydrocarbon cap is normally specified by the gas entry pressure (GEP) and the oil entry pressure (OEP), or just one of these if the trap contains only one hydrocarbon phase. However, MICP is often desired and useful also, primarily to enable comparisons to laboratory tests.)
(1) A gas specific gravity at D CTOC is found to match observed gas leg pressures using a black oil model (empirical correlations to determine reservoir fluid properties from field data taken in this case from McCain Jr., W. D., “Reservoir-fluid property correlations—state of the art,” SPE Reservoir Engineering 6, 266-272 (1991).
(a) Estimate a value for the gas specific gravity (γ G CTOC ) at D CTOC γ G CTOC . (b) Calculate pseudo-critical pressure (P pc CTOC ) at D CTOC by:
P pc CTOC =756.8−γ G CTOC (131+3.6γ G CTOC )
(c) Calculate pseudo-critical temperature (T pc CTOC ) at D CTOC by:
T pc CTOC =169.2−γ G CTOC (349.5+74.0γ G CTOC )
(d) Calculate pseudo-reduced temperature (T pr CTOC ) at D CTOC by:
T
pr
CTOC
=
(
T
CTOC
+
459.69
)
T
pc
CTOC
(e) Calculate pseudo-reduced pressure (P pr CTOC ) at D CTOC by:
P
pr
CTOC
=
P
G
CTOC
P
pc
CTOC
(f) Calculate gas formation volume factor (B g ):
B
g
=
0.00502
Z
(
T
CTOC
+
459.69
)
P
G
CTOC
(g) Calculate gas in-situ density (ρ g ):
ρ
g
=
0.21870617
(
(
0.001
)
Bg
)
γ
G
CTOC
(h) Compare predicted in-situ gas density to observed in-situ gas density.
(i) Use the difference between observed and predicted in-situ density to update the gas specific gravity guess (γ G CGOC ) at D CGOC in the first sub-step of step 73 .
(j) Repeat until the solution converges to obtain a gas gravity that matches observed pressure gradients to within an acceptable tolerance.
(2) Estimate Top Seal MICP.
(a) Calculate the brine-oil density contrast at the GOC (Δρ B-G )
Δρ B-G =(ρ B −ρ O )
(b) Use the brine-gas density differences to calculate the Firoozabadi Tau (τ—see Firoozabadi & Ramey, “Surface tension of water-hydrocarbon systems at reservoir conditions,” paper no. 87-38-30, presented at the 38 th Annual Technical Meeting of the Petroleum Society of CIM, Calgary (Jun. 7-10, 1987)).
τ= e [0.091251n(Δρ B-G ) 2 −0.538331n(Δρ B-G )+1.227328]
(c) Use the Firoozabadi Tau (τ) to calculate brine-gas interfacial tensions.
η B-G CTOC =[Δρ B-G ( T pr CTOC ) −0.3125 τ] 4
(d) Calculate an equivalent MICP for the current realization.
M I C P = 367.7 G E P CTOC η B - G CTOC
Step 74 : Estimate the Oil Entry Pressure (OEP) for Current Realization
(1) Find a gas specific gravity at D CGOC to match observed gas leg pressures using a black oil model (correlations from McCain (1991) in this case).
(a) Guess a value for the gas specific gravity (γ G CGOC ) at D CGOC . (b) Calculate pseudo-critical pressure (P pc CGOC ) at D CGOC by:
P pc CGOC =756.8−γ B CTOC (131+3.6γ B CTOC )
(c) Calculate pseudo-critical temperature (T pc CGOC ) at D CGOC by:
T pc CGOC =169.2−γ G CGOC (349.5+74.0γ G CGOC )
(d) Calculate pseudo-reduced temperature (T pr CGOC ) at D CGOC by:
T
pr
CGOC
=
(
T
CGOC
+
459.69
)
T
pc
CGOC
(e) Calculate pseudo-reduced pressure (P pr CGOC ) at D CGOC by:
P
pr
CGOC
=
P
G
CGOC
P
pc
CGOC
(f) Calculate gas formation volume factor (B g ):
B
g
=
0.00502
Z
(
T
CGOC
+
459.69
)
P
G
CGOC
(g) Calculate gas in-situ density (ρ g ):
ρ
g
=
0.21870617
(
0.001
B
g
)
γ
G
CGOC
(h) Compare predicted in-situ gas density to observed in-situ gas density
(i) Use the difference between observed and predicted in-situ density to update gas specific gravity guess (γ G CGOC ) at D CGOC in the first sub-step of step 74 .
(j) Repeat until the solution converges to obtain a gas gravity that matches observed pressure gradients to within an acceptable tolerance.
(2) Find an oil API gravity (γ API CGOC ) to match the observed oil leg pressures using a black oil model (correlations from McCain (1991) assuming saturation in this case).
(a) Guess a value for the oil API gravity (γ API CGOC ) at D CGOC . (b) Calculate the oil specific gravity (γ O CGOC ) at D CGOC .
γ
O
CGOC
=
141.5
(
γ
API
+
131.5
)
(c) Assuming saturation, calculate the solution gas/oil ratio (R s ) at D CGOC .
R
S
CGOC
=
γ
G
CGOC
[
(
P
G
CGOC
18.2
+
1.4
)
10
(
0.0125
ρ
API
-
0.0091
T
CGOC
)
]
(
-
0.83
)
(d) Calculate the saturated oil formation volume factor at the bubblepoint (B ob ).
B
ob
=
0.9759
+
0.00012
[
R
S
(
γ
G
CGOC
γ
O
CGOC
)
+
1.25
T
CGOC
]
1.2
(e) Calculate oil in-situ density (ρ o ):
ρ
O
=
(
γ
O
CGOC
+
0.0002179
*
R
S
CGOC
γ
G
CGOC
)
B
ob
(f) Use difference between observed and predicted in-situ density to update oil API gravity guess (γ API GOC ) at D CGOC in sub-step (a).
(g) Repeat until solution converges to obtain a γ API CGOC that matches observed pressure gradients.
(3) Calculate the OEP from the GEP.
(a) Calculate the molecular weight of the dead oil (M O STP ).
M O STP =433.646−10.1264(γ API CGOC −20.557)
(b) Calculate the critical temperature of the dead oil (T C STP ).
T C STP =23.8326281 n ( M O STP ) 2 +166.4536841 n ( M O STP )−300.639467
(c) Calculate the weight fraction of solution gas (f G GOC )
f
G
CGOC
=
(
R
S
CGOC
379.6
)
(
(
R
S
CGOC
379.6
)
+
350.565
(
γ
O
CGOC
M
O
STP
)
)
(d) Calculate the critical temperature of the live oil (T C CGOC ) at D CGOC .
T C CGOC =f G CGOC T pc CGOC +T C STP (1 −f G CGOC )
(e) Calculate the pseudo-reduced temperature of the live oil (T pr CGOC ) at D CGOC .
T
pr
CGOC
=
(
T
CGOC
+
459.69
)
T
C
CGOC
(f) Calculate the brine-oil density contrast at the GOC (Δρ O-B CGOC ).
Δρ B-O =(ρ B −ρ O )
(g) Use the brine-oil density differences to calculate the Firoozabadi Tau (τ).
τ= e [0.091251n(Δρ B-O ) 2 −0.538331n(Δρ B-O )+1.227328]
(h) Use the Firoozabadi Tau (τ) to calculate oil-brine interfacial tensions.
η B-O CGOC =[Δρ B-O ( T pr CGOC ) −0.3125 τ] 4
(i) Calculate the oil entry pressure.
O E P CGOC = M I C P ( η B - O CGOC ) 367.7
Step 75 : Obtain Statistical Distribution of Seal Capacity Estimates for Calibration Location
Repeat steps 71 - 74 a predetermined number of times, averaging the results and calculating an uncertainty spread in MICP, GEP CTOC , and OEP CGOC .
Step 76 : Combine Distributions of Seal Capacity Estimates from any Other Calibration Locations
Repeat steps 71 - 75 for each calibration location summing the probability distributions for MICP, GEP CTOC , and OEP CGOC .
The person skilled in the art will recognize that the preceding embodiment also has value, compared to traditional approaches, as a stand alone method for estimating capillary seal capacity, either with the uncertainty estimate, or if desired, without. In the latter case in its most direct form, input parameter values would need to be selected in step 71 , but for the prospect location. Then, steps 72 - 74 would be performed as described above.
Estimating Hydraulic Fracture Pressure (Step 62 )
A detailed discussion follows of a preferred embodiment for estimating the mechanical seal capacity and associated uncertainty at a calibration location.
The basis for the deterministic mechanical seal capacity calculation resides with an evaluation of the effective stress of the reservoir at the top of the hydrocarbon column. As reservoir fluid pressures increase (i.e., hydraulic pressure at the top of the hydrocarbon column height increases), the effective stress decreases and there is an increased risk that the reservoir fluid pressure may open tensile fractures in the top seal (reservoir fluid pressures at this point equal or exceed the hydraulic fracture pressure, or P f ), thereby allowing hydrocarbons to escape. Two common occurrences increase the hydraulic pressure at the top of the hydrocarbon column: 1) an increase in hydrocarbon column height; and 2) an increase in reservoir aquifer pressure associated with an existing hydrocarbon column.
The techniques of the embodiment being described assist with the use of contact information to calculate mechanical seal capacity with respect to minimum compressive stress. This preferred embodiment is based on work by Mandl and Harkness, “Hydrocarbon migration by hydraulic fracturing” in Deformation of Sediments and Sedimentary Rocks , Geological Special Publication 29, 39-54, Jones and Preston, Ed's (1987) and Miller, T. W., “New insights on natural hydraulic fractures induced by abnormally high pore pressures,” AAPG Bulletin 79, 1005-1018 (1995). These workers established a purely deterministic method to estimate the size of a hydrocarbon column necessary to hydrofracture the top seal of a trap, and to identify possible controls on single-phase hydrocarbon column heights.
Hydraulic fracture pressure is prescribed as a functional relationship between pressure and depth. This relationship may be manually specified by the user based on a priori knowledge. In other embodiments of the invention, this relationship may be calculated by at least two means: a linear “least-squares” regression to LOT (leak-off test) data or through determination of σ h min as described previously herein.
Input Quantities
For empirical hydraulic fracture pressure estimation, the following inputs are used in some embodiments of the invention:
Leak-off test data from calibration location(s). Operational data, such as lost returns incidents, from calibration location(s).
For theoretical hydraulic fracture pressure estimation, the following inputs are used in some embodiments of the invention:
Lithostatic pressure as a function of depth with uncertainty range (P Lith ). Pore pressure as a function of depth with uncertainty range (P Pore ). Ratio of minimum and maximum effective stress (k o ) with uncertainty range.
The empirical hydraulic fracture pressure estimation may be performed by following the following basic steps:
(1) Plot the empirical data as a function of depth. (2) Calculate (a) simple best-fit linear regression line(s), minimizing the sum-of-squares of the vertical distances between the points and the line(s) by a technique such as that outlined in Davis, Statistics and Data Analysis in Geology, 2 nd Edition, John Wiley and Sons, Inc., USA, 176-204 (1986). (3) Calculate standard confidence intervals, deriving a relationship between depth and fracture pressure with associated uncertainties by a technique such as that outlined in Davis (1986).
The theoretical hydraulic fracture pressure estimation may be performed by following the following basic steps:
(1) Plot P Lith and P Pore with associated uncertainty ranges as a function of depth. (2) Calculate vertical effective stress (σ eff =P Lith −P Pore ) and associated uncertainty range. (3) Calculate the minimum horizontal stress (σ h min ) and associated uncertainty range via:
σ h min =k o σ eff +P pore
where
k o = σ 3 - P pore σ 1 - P pore
(for a uniaxial compressive state where compaction is in one direction with no lateral strains)=ratio of minimum and maximum effective stress; approximately 0.4 for strong materials to >0.8 for shale/clay.
(4) Repeat to determine minimum, most likely, and maximum values for σ min as a function of depth.
Probabilistic Calculation of Column Heights (Steps 64 - 67 )
Steps 61 and 62 of a preferred embodiment have been described in detail, and with those descriptions, also step 63 . These steps result in probability-weighted distributions for trap and fluid parameters at the prospect location, capillary entry pressure from calibration location(s), and hydraulic fracture pressure from calibration location(s). Next is the probabilistic procedure. A key to this analysis is recognition that the probability-weighted distributions of mechanical and capillary seal capacities must be adjusted to account for differences between the trap and fluid parameters at the calibration location and those selected in each realization of the prospect parameter distribution. In preferred embodiments of the invention, uncertainty distributions are assigned to all input parameters. The uncertainties are propagated throughout the analysis, enabling a statistical analysis of probabilistic simulation for risking and assessment.
Input quantities for the probabilistic calculation steps include the following.
Probability weighted distributions of prospect trap parameters (from step 63 ):
Top of column (D PTOC ).
Spill (D W ).
Prospect temperature (T PTOC ) at D PTOC .
Prospect water depth (D W ).
Probability weighted distributions of prospect fluid parameters (from step 63 ):
In-situ oil density (ρ O )
In-situ gas density (ρ G )
In-situ brine density (ρ B )
Formation pore excess pressure (P E )
Probability weighted distributions of capillary entry pressure (from step 61 ):
MICP
Multiple fracture pressure vs. depth curves with associated confidence intervals (from step 62 ).
Following are steps in the preferred embodiment of the probabilistic calculation, with number references to the flow chart of FIG. 6 .
Randomly Select a Value from Input Parameter Distributions (Step 64 ).
From selected inputs, calculate:
a) Brine pressure at D PTOC .
P B =ρ SW gD W +ρ B gD PTOC +P E
Revise Oil Entry Pressure (OEP) and Gas Entry Pressure (GEP) Calculated from the Calibration Location(s) for Present Realization Prospect Conditions (Step 65 ).
(1) Calculate the prospect gas entry pressure from the MICP value determined from the calibration location(s), evaluating the gas properties at D PTOC :
(a) Find a gas gravity (γ G ) that produces the selected in-situ density (ρ G ) as in step 73 of FIG. 7 . (b) Calculate the pseudo-critical gas temperature (T pc ) by:
T pc =169.2+γ G (349.5−74γ G )
(c) Calculate pseudo-reduced gas temperature (T pr PTOC ) by: (d) Calculate the brine-gas density contrast (Δρ B-G ):
Δρ B-G =(ρ B −ρ G )
(e) Use the brine-gas density difference to calculate the Firoozabadi Tau (τ).
τ= e [0.091251n(Δρ B-G ) 2 −0.538331n(Δρ B-G )+1.227328]
(f) Use the Firoozabadi Tau (τ) to calculate brine-gas interfacial tension.
η B-G PTOC =[Δρ B-G ( T pr PTOC ) −0.3125 τ] 4
(g) Use the brine-gas interfacial tension (η B-G PTOC ) at the prospect D PTOC to calculate the GEP at the prospect D PTOC :
G
E
P
PTOC
=
(
η
B
-
G
PTOC
)
M
I
C
P
367.7
(2) Calculate the prospect oil entry pressure from the MICP value determined from the calibration location(s), evaluating the oil properties at D PTOC :
(a) Find an oil API gravity (γ API PTOC ) and an oil specific gravity (γ O PTOC ) to match selected in-situ density using a black oil model as in step 74 of FIG. 7 . (b) Assuming saturation, calculate the solution gas/oil ratio (R s PGOC ) at D PTOC :
R
s
PTOC
=
γ
G
[
(
P
B
PTOC
18.2
+
1.4
)
10
(
0.0125
γ
API
PTOC
-
0.0091
T
PTOC
)
]
(
-
0.83
)
(c) Calculate effective molecular weight (M Weff ).
M Weff =433.646−10.1264(γ API PTOC −20.557)
(d) Calculate the critical temperature of the dead oil (T C STP )
T C STP =23.832628 log( M Weff ) 2 −0.53833 log( M Weff )+1.227328
(e) Calculate the weight fraction of solution gas (f G PGOC )
f
G
PTOC
=
(
R
s
PTOC
379.6
)
(
(
R
s
PTOC
379.6
)
+
350.565
(
γ
O
PTOC
M
Weff
)
)
(f) Calculate the critical temperature of the live oil (T C PGOC ) at D PGOC .
T C PTOC =f G PTOC T pc PTOC +T C STP (1 −f G PTOC )
g) Calculate the pseudo-reduced temperature of the live oil (T pr PTOC ) at D PTOC .
T
pr
PTOC
=
(
T
PTOC
+
459.6
)
T
C
PTOC
h) Calculate the brine-oil density contrast (Δρ O-B PTOC ).
Δρ B-O PTOC =(ρ B −ρ O PTOC )
i) Use the brine-oil density differences to calculate the Firoozabadi Tau (τ).
τ= e [0.091251n(Δρ B-O PTOC ) 2 −0.538331n(Δρ B-O PTOC )+1.227328 ]
j) Use the Firoozabadi Tau (τ) to calculate oil-brine interfacial tensions.
η B-O PTOC =[Δρ B-O PTOC ( T pr PTOC ) −0.3125 τ] 4
k) Calculate the oil entry pressure.
O E P PTOC = ( η B - O PTOC ) M I C P 367.7
Revise Hydraulic Fracture Pressure Based Upon Selected Trap Parameters in the Present Realization (Step 66 ).
1) For empirical hydraulic fracture pressure model (from step 62 ), calculate a probability-weighted distribution of hydraulic fracture pressure at D PTOC : (i) Referring to FIG. 8 , equate best-fit (preferably in a least-squares sense) regression line 81 and 68.27% standard confidence intervals 82 determined at the estimated crest depth 84 of the subject trap, D PTOC , to specify the mean 86 and one standard deviation 87 of a normal (Gaussian) distribution 85 of hydraulic fracture pressures. This determines the topology of the normal distribution curve from which the random trials will select hydraulic fracture pressures. The fracture pressure data points 83 plotted in FIG. 8 may be obtained, for example, from leak-off tests conducted at the calibration location(s). The estimate of the subject trap's crest depth may be obtained, for example, from seismic data.
(ii) Randomly select from the probability-weighted distribution from step (i) a hydraulic fracture pressure value (P f ) for the present realization.
2) For hydraulic theoretical fracture pressure model (from step 62 ), calculate a probability-weighted distribution of hydraulic fracture pressure at D PTOC
(i) Referring to FIG. 9 , equate most likely 91 , minimum 92 , and maximum 93 σ h min (i.e., P Frac ) determined at the estimated crest depth 95 for the subject trap, D PTOC , to specify the most likely, minimum, and maximum values on a triangular distribution 94 of fracture pressures. The theoretical fracture pressure model is used to generate the curves 96 , 97 and 98 . (ii) Randomly select from this probability-weighted distribution a hydraulic fracture pressure value (P f ) for the present realization.
Calculate Hydrocarbon Column Heights Consistent with Trap Parameters, Fluid Parameters, Hydraulic Fracture Pressure, OEP, and GEP in Present Realization (Step 67 ).
Alternative potential cases are depicted in FIGS. 5A-F . The procedure requires equating the calculated OEP and GEP to the buoyancy of the hydrocarbon column relative to the associated aquifer pressure gradient for capillary seal capacity, and equating the absolute pressure at the top of the hydrocarbon column (trap crest) to P f at the top of the column (trap crest) for mechanical seal capacity. The height of the hydrocarbon column (gas, oil, or combination of both) required to achieve the necessary buoyancy or absolute pressure is the seal capacity for that realization.
Repeat Steps 74 - 77 to Obtain More Realizations (Step 68 ). (Self Explanatory)
CONCLUSION
The foregoing application is directed to particular embodiments of the present invention for the purpose of illustrating it. It will be apparent, however, to one skilled in the art, that many modifications and variations to the embodiments described herein are possible. For example, a probability-weighted distribution which is random sampled in the present invention may be a single value assigned a probability of unity. Furthermore, it should be apparent to persons skilled in the art that detailed explanations presented hereinabove of how the steps of FIGS. 6 and 7 might be performed constitute but one or a few specific embodiments of the present inventive method, and are not intended to limit the broader description in the claims which is drafted to include all embodiments. To disclose all embodiments at this same level of detail would be both (a) impossible and (b) unnecessary for the understanding of the skilled practitioner. All such modifications and variations are intended to be within the scope of the present invention, as defined in the appended claims. The reader skilled in the art will also recognize that the invention will preferably be practiced with computer implementation, meaning that at least some parts of the method are performed on a computer.
Glossary of Abbreviations
B g
Formation volume factor of dry gas, res ft 3 /scf or RB/scf
B ob
Saturation oil formation volume factor, RB/STB
D
Depth (ft)
f
Weight fraction
g
Gravitational constant
GEP
Gas entry pressure (psi)
IFT
Interfacial tension (dynes/cm 2 )
k o
lithology dependent horizontal to vertical stress ratio
MICP
Mercury-injection capillary pressure
OEP
Oil entry pressure (psi)
P
Pressure (psi)
R s
Solution gas-oil ratio
T
Temperature (° F.)
Z
Z factor
Symbols
γ
Specific gravity (w/respect to air for gas or water for oil) e
η
Interfacial tension
ρ
Density (g/cm 3 )
σ
Stress (psi)
σ eff
Effective stress (psi)
σ hmin
Horizontal minimum stress (psi)
σ 1
Maximum compressive stress
σ 3
Minimum compressive stress
τ
Firoozabadi tau
Superscripts
TOC
Top of column
OWC
Oil-water contact
GOC
Gas-oil contact
C
Calibration location
P
Prospect location
STP
Standard temperature and pressure (60° F., 14.65 psia)
Subscripts
API
American Petroleum Institute
B
Brine
O
Oil
G or g
Gas
lith
Lithostatic
pore
Pore
pc
Pseudo-critical
pr
Pseudo-reduced
F or f
Fracture
Hg
Mercury
a
Air
|
Method for making a probabilistic determination of total seal capacity for a hydrocarbon trap, simultaneously considering both capillary entry pressure and mechanical seal capacity, and where capillary entry pressure is estimated by relating it directly to the buoyancy pressure applied by the hydrocarbon column to the top seal. The method thus considers the substantial uncertainty associated with input parameters, which uncertainty limits the utility of such analyses for robust hydrocarbon column height and fluid contact predictions. The method disclosed for estimating seal capillary entry pressure, the requisite input parameter for capillary seal capacity analysis, by inverting trap parameters avoids the need for direct measurement by mercury injection capillary capacity tests on small pieces of rock, which test results often are not available for all desired locations nor are they necessarily representative of adjacent rocks in the seal.
| 4
|
CROSS-REFERENCE
[0001] This application is a continuation of U.S. application Ser. No. 09/251,981, filed Feb. 17, 1999, entitled “Transmit Gating in a Wireless Communication System” which claims the benefit of U.S. provisional application No. 60/075,211, filed on Feb. 19, 1998 both are assigned to the assignee of the present invention. The disclosure of this provisional application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] I. Field of the Invention
[0003] The present invention relates to communications. More particularly, the present invention relates to a novel and improved method and apparatus for transmitting variable rate data in a wireless communication system, and for assisting a hard handoff.
[0004] II. Description of the Related Art
[0005] The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA) and frequency division multiple access (FDMA) are known in the art. However, the spread spectrum modulation techniques of CDMA have significant advantages over these modulation techniques for multiple access communication systems. The use of CDMA techniques in a multiple access communication system is disclosed in U.S. Pat. No. 4,901,307, entitled “SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS”, assigned to the assignee of the present invention, and incorporated by reference herein. The use of CDMA techniques in a multiple access communication system is further disclosed in U.S. Pat. No. 5,103,459, entitled “SYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM”, assigned to the assignee of the present invention and incorporated by reference herein.
[0006] CDMA by its inherent nature of being a wideband signal offers a form of frequency diversity by spreading the signal energy over a wide bandwidth. Therefore, frequency selective fading affects only a small part of the CDMA signal bandwidth. Space or path diversity is obtained by providing multiple signal paths through simultaneous links from a mobile user through two or more cell-sites. Furthermore, path diversity may be obtained by exploiting the multipath environment through spread spectrum processing by allowing a signal arriving with different propagation delays to be received and processed separately. Examples of path diversity are illustrated in U.S. Pat. No. 5,101,501 entitled “METHOD AND SYSTEM FOR PROVIDING A SOFT HANDOFF IN COMMUNICATIONS IN A CDMA CELLULAR TELEPHONE SYSTEM”, and U.S. Pat. No. 5,109,390 entitled “DIVERSITY RECEIVER IN A CDMA CELLULAR TELEPHONE SYSTEM”, both assigned to the assignee of the present invention and incorporated by reference herein.
[0007] A method for transmission of speech in digital communication systems that offers particular advantages in increasing capacity while maintaining high quality of perceived speech is by the use of variable rate speech encoding. The method and apparatus of a particularly useful variable rate speech encoder is described in detail in U.S. Pat. No. 5,414,796, entitled “VARIABLE RATE VOCODER”, assigned to the assignee of the present invention and incorporated by reference herein.
[0008] The use of a variable rate speech encoder provides for data frames of maximum speech data capacity when the speech encoder is providing speech data at a maximum rate. When the variable rate speech encoder is providing speech data at a less that maximum rate, there is excess capacity in the transmission frames. A method for transmitting additional data in transmission frames of a fixed predetermined size, wherein the source of the data for the data frames is providing the data at a variable rate, is described in detail in U.S. Pat. No. 5,504,773, entitled “METHOD AND APPARATUS FOR THE FORMATTING OF DATA FOR TRANSMISSION”, assigned to the assignee of the present invention and incorporated by reference herein. In the above mentioned patent application, a method and apparatus is disclosed for combining data of differing types from different sources in a data frame for transmission.
[0009] In frames containing less data than a predetermined capacity, power consumption may be lessened by transmission gating a transmission amplifier such that only parts of the frame containing data are transmitted. Furthermore, message collisions in a communication system may be reduced if the data is placed into frames in accordance with a predetermined pseudorandom process. A method and apparatus for gating the transmission and for positioning the data in the frames is disclosed in U.S. Pat. No. 5,659,569, entitled “DATA BURST RANDOMIZER”, assigned to the assignee of the present invention and incorporated by reference herein.
[0010] A useful method of power control of a mobile in a communication system is to monitor the power of the received signal from the wireless communication device at a base station. In response to the monitored power level, the base station transmits power control bits to the wireless communication device at regular intervals. A method and apparatus for controlling transmission power in this fashion is disclosed in U.S. Pat. No. 5,056,109, entitled “METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM”, assigned to the assignee of the present invention and incorporated by reference herein.
[0011] In a communication system that provides data using a QPSK modulation format, very useful information can be obtained by taking the cross product of the I and Q components of the OPSK signal. By knowing the relative phases of the two components, one can determine roughly the velocity of the wireless communication device in relation to the base station. A description of a circuit for determining the cross product of the I and Q components in a QPSK modulation communication system is disclosed in U.S. Pat. No. 5,506,865, entitled “PILOT CARRIER DOT PRODUCT CIRCUIT”, assigned to the assignee of the present invention and incorporated by reference herein.
[0012] There has been an increasing demand for wireless communications systems to be able to transmit digital information at high rates. One method for sending high rate digital data from a wireless communication device to a central base station is to allow the wireless communication device to send the data using spread spectrum techniques of CDMA. One method that is proposed is to allow the wireless communication device to transmit its information using a small set of orthogonal channels. Such a method is described in detail in co-pending U.S. Pat. No. 6,396,804, entitled “HIGH DATA RATE CDMA WIRELESS COMMUNICATION SYSTEM”, assigned to the assignee of the present invention and incorporated by reference herein.
[0013] In the just-mentioned application, a system is disclosed in which a pilot signal is transmitted on the reverse link (the link from the wireless communication device to the base station) to enable coherent demodulation of the reverse link signal at the base station. Using the pilot signal data, coherent processing can be performed at the base station by determining and removing the phase offset of the reverse link signal. Also, the pilot data can be used to optimally weigh multipath signals received with different time delays before being combined in a rake receiver. Once the phase offset is removed, and the multipath signals properly weighted, the multipath signals can be combined to decrease the power at which the reverse link signal must be received for proper processing. This decrease in the required receive power allows greater transmission rates to be processed successfully, or conversely, the interference between a set of reverse link signals to be decreased.
[0014] While some additional transmit power is necessary for the transmission of the pilot signal, in the context of higher transmission rates the ratio of pilot signal power to the total reverse link signal power is substantially lower than that associated with lower data rate digital voice data transmission cellular systems. Thus, within a high data rate CDMA system, the E b /N 0 gains achieved by the use of a coherent reverse link outweigh the additional power necessary to transmit pilot data from each wireless communication device.
[0015] An additional benefit of the reverse link described in this co-pending application is that it generates less amplitude modulation (AM) interference due to its continuous-transmit nature. Thus, users with sensitive electronic equipment such as hearing aids and pacemakers will experience less interference than with a discontinuous transmit reverse link. Another example of the use of continuous transmission to reduce AM interference is given in co-pending U.S. Pat. No. 6,205,190, filed Apr. 29, 1996, entitled “SYSTEM AND METHOD FOR REDUCING INTERFERENCE GENERATED BY A CDMA COMMUNICATIONS DEVICE”, assigned to the assignee of the present invention and incorporated herein by reference.
[0016] However, when the data rate is relatively low, a continuously-transmitted pilot signal on the reverse link contains more energy relative to the data signal. At these low rates, the benefits of coherent demodulation and reduced interference provided by a continuously-transmitted reverse link pilot signal may be outweighed by the decrease in talk time and system capacity in some applications. A method and system is needed to provide flexibility in reverse link transmission format as needed-to optimize these tradeoffs.
[0017] Further, a communications device may need to go into hard handoff from a first system to a second system. If discontinuous transmission is possible, the device may search for the second system during the periods of non-transmission, while maintaining contact with the first system during periods of transmission.
SUMMARY OF THE INVENTION
[0018] The present invention is a novel and improved method and system for communicating a frame of information according to both a continuous transmit format and a discontinuous transmit format. In one aspect of the present invention, a method is disclosed for transmitting frames of information. The method includes transmitting information continuously throughout the frame when in a continuous transmit mode and the frame is of a first data rate of a plurality of data rates; and transmitting the information discontinuously in the frame when in a discontinuous transmit mode and the frame is of the first data rate. Thus, the present invention contemplates transmitting one or more data rates in either a continuous transmit mode or a discontinuous transmit mode.
[0019] The method may further include transmitting the information continuously throughout the frame when the frame is of a second data rate of the plurality of data rates. Thus, the present invention contemplates continuous transmission only for certain data rates, and selection between continuous and discontinuous transmission for other data rates.
[0020] In one embodiment of the present invention, the first data rate corresponds to a first transmit power and the second data rate corresponds to a second transmit power, and the first transmit power is less than the second transmit power. In this embodiment, the method includes transmitting the frame of the first data rate at the second transmit power when in the discontinuous transmit mode. Thus, frames transmitted in the discontinuous transmit mode may be transmitted at a higher transmit power than in the continuous transmit mode.
[0021] In one embodiment of the present invention, the information is transmitted at a fifty-percent duty cycle during the frame when in the discontinuous transmit mode. This may include transmitting the information during a second half of the frame.
[0022] Another embodiment of the present invention includes selecting between the continuous transmit mode and the discontinuous transmit mode in response to a transmit power of the wireless communication device. In other words, the present invention may include selecting the discontinuous transmit mode when the transmit power is less than a predetermined threshold. In an alternate embodiment, the present invention includes selecting between the continuous transmit mode and the discontinuous transmit mode according to a user-defined preference.
[0023] The present invention also contemplates a wireless communication device for transmitting frames of information. The wireless communication device includes a variable rate data source for generating the frames of information, each of the frames of information having one of a plurality of data rates. It also includes a transmitter for transmitting the information continuously throughout the frame when in a continuous transmit mode and when the frame is of a first data rate of the plurality of data rates, and for transmitting the information discontinuously in the frame when in a discontinuous transmit mode and when the frame is of the first data rate. Thus, the wireless communication device may transmit frames of a given data rate either continuously or discontinuously. A control processor selects between the continuous transmit mode and the discontinuous transmit mode. The wireless communication device may implement the method of the present invention as summarized briefly above.
[0024] The present invention also includes a method for receiving a frame of information in a wireless receiver, wherein the information may be continuously present throughout the frame or discontinuously present in the frame. This method includes filtering the frame of information in a sliding window filter to produce a sliding window phase estimate signal, filtering the frame of information in a block window filter to produce a block window phase estimate signal, and selecting between the sliding window phase estimate signal and the block window phase estimate signal in response to whether the information is continuously present in the frame.
[0025] In one embodiment of the present invention, the method includes selecting the sliding window phase estimate signal when the information is continuously present in the frame, and selecting the block window phase estimate signal when the information is discontinuously present in the frame. Additionally, the method may include selecting the block window phase estimate signal before and after a phase discontinuity in the frame.
[0026] The present invention further contemplates a wireless receiver for receiving a frame of information wherein the information may be continuously present throughout the frame or discontinuously present in the frame. The wireless receiver includes a sliding window phase estimator for filtering the frame of information in a sliding window to produce a sliding window phase estimate signal, a block window phase estimator for filtering the frame of information in a block window to produce a block window phase estimate signal, and a multiplexer for selecting between the sliding window phase estimate signal and the block window phase estimate signal in response to whether the information is continuously present in the frame. The wireless receiver may implement the method briefly described above.
[0027] Additionally, the present invention discloses a method, in a wireless communication system, for communicating a frame of information between a wireless communication device and a wireless base station in a continuous transmit mode and a discontinuous transmit mode. The method includes transmitting, from the wireless communication device, the information continuously throughout the frame when in the continuous transmit mode, and transmitting, from the wireless communication device, a first message notifying the wireless base station of an intention to transmit in a discontinuous mode. In response, the base station transmits a second message acknowledging the intention to transmit in the discontinuous mode, and the wireless communication device transmits the information discontinuously in the frame when in the discontinuous transmit mode, and in response to the second message.
[0028] In one embodiment, the method further includes demodulating the frame of information according to a continuous transmit format when the information is continuously present throughout the frame, and demodulating, the frame of information according to a discontinuous transmit format when the information is discontinuously present in the frame.
[0029] The present invention further contemplates a wireless communication system for communicating a frame of information in a continuous transmit mode and a discontinuous transmit mode. The wireless communication system includes a wireless communication device and a wireless base station that implement the method described briefly above.
[0030] In a final aspect of the present invention, a method and apparatus are disclosed for facilitating hard handoff from a first system to a second system. The device searches for the second system during the periods of non-transmission, while maintaining contact with the first system during periods of transmission.
[0031] Gating is supported for rate sets 3, 4, 5 and 6. When a frame is gated, only the symbols within the second half of the frame are sent. This means that symbols 6144 through 12287, numbering from 0, are transmitted. During gating, the maximum frame rate is rate 1/2.
[0032] Normally, the blocks are transmitted using continuous transmission, with the exception of the rate 1/8 frame which is gated. The continuous transmission reduces the interference in the audio band. The rate 1/8 frame is gated because it improves the reverse link capacity and the mobile station talk time relative to when continuous transmission is used.
[0033] However, rate set 3, 4, 5 and 6 may be commanded into a mode where only rate 1/8, rate 1/4, and rate 1/2 frames are transmitted and are transmitted using gated transmission. This mode is used to allow the mobile station time to retune its receiver and search for systems using frequencies and other technologies (e.g. AMPS and GSM).
[0034] During gating, the second half of the frame is transmitted for the following reasons. First, the gating needs to be either in the first half or the second half of the frame. If it were not, then the frame would not contain a contiguous 10 milliseconds for searching. Second, the transmitted portion of the frame needs to occur later in the frame in order to allow the mobile station time to estimate the difference between the measured and expected forward signal to noise ratio. Therefore, during gating, the second half of the frame is sent.
[0035] In addition, rate set 3, 4, 5 and 6 may be commanded into a mode where all frames are transmitted using continuous transmission. This mode is used by mobile stations that may need to further reduce audio band interference. A mobile station commanded into gated mode for searching will be commanded to periodically gate N frames out of M frames on the forward link and reverse link simultaneously, starting at system time T. The values of N and M depend on the technology being searched and the number of channels being searched.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout and wherein:
[0037] [0037]FIG. 1 is a functional block diagram of an exemplary embodiment of the transmission system of the present invention embodied in wireless communication device 50 ;
[0038] [0038]FIG. 2 is a functional block diagram of an exemplary embodiment of modulator 26 of FIG. 1;
[0039] [0039]FIG. 3 illustrates four graphs of the average energy transmitted by transmitter 28 of FIG. 1 over a single frame for four different data rates;
[0040] [0040]FIG. 4 is a functional block diagram of selected portions of a base station 400 in accordance with the present invention;
[0041] [0041]FIG. 5 is an expanded functional block diagram of an exemplary single demodulation chain of demodulator 404 of FIG. 4; and
[0042] [0042]FIG. 6 is an expanded functional block diagram of an exemplary pilot filter that uses a sliding window estimator in combination with a block window estimator.
[0043] [0043]FIG. 7 is a block diagram of apparatus for assisting in hard handoff.
[0044] [0044]FIG. 8 is a block diagram of a method for assisting in hard handoff.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] [0045]FIG. 1 illustrates a functional block diagram of an exemplary embodiment of the transmission system of the present invention embodied in wireless communication device 50 . It will be understood by one skilled in the art that the methods described herein could be applied to transmission from a central base station (not shown) as well. It will also be understood that various of the functional blocks shown in FIG. 1 may not be present in other embodiments of the present invention. The functional block diagram of FIG. 1 corresponds to an embodiment that is useful for operation according to the TIA/EIA Standard IS-95C, also referred to commercially as cdma2000. Other embodiments of the present invention are useful for other standards including Wideband CDMA standards and dual-mode CDMA/GSM standards. These other embodiments differ somewhat in the formatting of data for transmission, but still include the inventive principles described herein.
[0046] In the exemplary embodiment of FIG. 1, the wireless communication device transmits a plurality of distinct channels of information which are distinguished from one another by short orthogonal spreading sequences as described in the aforementioned U.S. Pat. No. 6,396,804. Five separate code channels are transmitted by the wireless communication device: 1) a first supplemental data channel 38 , 2) a time multiplexed channel of pilot and power control symbols 40 , 3) a dedicated control channel 42 , 4) a second supplemental data channel 44 and 5) a fundamental channel 46 . The first supplemental data channel 38 and second supplemental data channel 44 carry digital data which exceeds the capacity of the fundamental channel 46 such as facsimile, multimedia applications, video, electronic mail messages or other forms of digital data. The multiplexed channel of pilot and power control symbols 40 carries pilots symbols to allow for coherent demodulation of the data channels by the central base station and power control bits to control the energy of transmissions to wireless communication device 50 . Control channel 42 carries control information to the central base station such as modes of operation of wireless communication device 50 , capabilities of wireless communication device 50 and other necessary signaling information. Fundamental channel 46 is the primary channel used to carry the primary information signal from the wireless communication device to the central base station. In the case of speech transmissions, the fundamental channel 46 carries the speech data.
[0047] Supplemental data channels 38 and 44 are encoded and processed for transmission by means not shown and provided to modulator 26 . Power control bits are provided to repetition generator 22 which provides repetition of the power control bits before providing the bits to multiplexer (MUX) 24 . In multiplexer 24 the redundant power control bits are time multiplexed with pilot symbols and provided on line 40 to modulator 26 .
[0048] Message generator 12 generates necessary control information messages and provides the control message to CRC and tail bit generator 14 . CRC and tail bit generator 14 appends a set of cyclic redundancy check bits which are parity bits used to check the accuracy of the decoding at the central base station and appends a predetermined set of tail bits to the control message. The message is then provided to encoder 16 which provide forward error correction coding upon the control message. The encoded symbols are provided to interleaver 18 which reorders the symbols in accordance with a predetermined interleaver format. The interleaved symbols are provided to repetition generator 20 which repeats the reordered symbols to provide additional time diversity in the transmission. The interleaved symbols are provided on line 42 to modulator 26 .
[0049] Variable rate data source 1 generates variable rate data. In the exemplary embodiment, variable rate data source 1 is a variable rate speech encoder such as described in aforementioned U.S. Pat. No. 5,414,796. Variable rate speech encoders are popular in wireless communications because their use increases the battery life of wireless communication devices and increases system capacity. The Telecommunications Industry Association has codified the most popular variable rate speech encoders in such standards as Interim Standard IS-96 and Interim Standard IS-733. These variable rate speech encoders encode the speech signal at four possible rates referred to as full rate, half rate, quarter rate or eighth rate according to the level of voice activity. The rate indicates the number of bits used to encode a frame of speech and varies on a frame by frame basis. Full rate uses a predetermined maximum number of bits to encode the frame, half rate uses half the predetermined maximum number of bits to encode the frame, quarter rate uses one quarter the predetermined maximum number of bits to encode the frame and eighth rate uses one eighth the predetermined maximum number of bits to encode the frame.
[0050] Variable rate date source 1 provides the encoded speech frame to CRC and tail bit generator 2 . CRC and tail bit generator 2 appends a set of cyclic redundancy check bits which are parity bits used to check the accuracy of the decoding at the central base station and appends a predetermined set of tail bits to the control message. The frame is then provided to encoder 4 which provide forward error correction coding on the speech frame. The encoded symbols are provided to interleaver 6 which reorders the symbols in accordance with a predetermined interleaver format. The interleaved symbols are provided to repetition generator 8 which provided repetition of the reordered symbols to provide additional time diversity in the transmission. The interleaved symbols are provided on line 46 to modulator 26 .
[0051] In the exemplary embodiment, modulator 26 modulates the data channels in accordance with a code division multiple access modulation format and provides the modulated information to transmitter (TMTR) 28 which amplifies and filters the signal and provides the signal through duplexer 30 for transmission through antenna 32 .
[0052] [0052]FIG. 2 illustrates a functional block diagram of an exemplary embodiment of modulator 26 of FIG. 1. The first supplemental data channel data is provided on line 38 to spreading element 52 which covers the supplemental channel data in accordance with a predetermined spreading sequence. In the exemplary embodiment, spreading element 52 spreads the supplemental channel data with a short Walsh sequence (+−−+). The spread data is provided to relative gain element 54 which adjusts the gain of the spread supplemental channel data relative to the energy of the pilot and power control symbols. The gain adjusted supplemental channel data is provided to a first summing input of summer 56 . The pilot and power control multiplexed symbols are provided on line 40 to a second summing input of summing element 56 .
[0053] Control channel data is provided on line 42 to spreading element 58 which covers the supplemental channel data in accordance with a predetermined spreading sequence. In the exemplary embodiment, spreading element 58 spreads the supplemental channel data with a short Walsh sequence (++++−−−−). The spread data is provided to relative gain element 60 which adjusts the gain of the spread control channel data relative to the energy of the pilot and power control symbols. The gain adjusted control data is provided to a third summing input of summer 56 .
[0054] Summing element 56 sums the gain adjusted control data symbols, the gain adjusted supplemental channel symbols and the time multiplexed pilot and power control symbols and provides the sum to a first input of multiplier 72 and a first input of multiplier 78 .
[0055] The second supplemental channel is provided on line 44 to spreading element 62 which covers the supplemental channel data in accordance with a predetermined spreading sequence. In the exemplary embodiment, spreading element 62 spreads the supplemental channel data with a short Walsh sequence (+−+−). The spread data is provided to relative gain element 64 which adjusts the gain of the spread supplemental channel data. The gain adjusted supplemental channel data is provided to a first summing input of summer 66 .
[0056] The fundamental channel data is provided on line 46 to spreading element 68 which covers the fundamental channel data in accordance with a predetermined spreading sequence. In the exemplary embodiment, spreading element 68 spreads the supplemental channel data with a short Walsh sequence (++−−). The spread data is provided to relative gain element 70 which adjusts the gain of the spread fundamental channel data. The gain adjusted fundamental channel data is provided to a second summing input of summer 66 .
[0057] Summing element 66 sums the gain adjusted second supplemental channel data symbols and the fundamental channel data symbols and provides the sum to a first input of multiplier 74 and a first input of multiplier 76 .
[0058] In the exemplary embodiment, a pseudonoise spreading using two different short PN sequences (PN I and PN Q ) is used to spread the data. In the exemplary embodiment the short PN sequences, PN I and PN Q , are multiplied by a long PN code to provide additional privacy. The generation of pseudonoise sequences is well known in the art and is described in detail in aforementioned U.S. Pat. No. 5,103,459. A long PN sequence is provided to a first input of multipliers 80 and 82 . The short PN sequence PNI is provided to a second input of multiplier 80 and the short PN sequence PNQ is provided to a second input of multiplier 82 .
[0059] The resulting PN sequence from multiplier 80 is provided to respective second inputs of multipliers 72 and 74 . The resulting PN sequence from multiplier 82 is provided to respective second inputs of multipliers 76 and 78 . The product sequence from multiplier 72 is provided to the summing input of subtractor 84 . The product sequence from multiplier 74 is provided to a first summing input of summer 86 . The product sequence from multiplier 76 is provided to the subtracting input of subtractor 84 . The product sequence from multiplier 78 is provided to a second summing input of summer 86 .
[0060] The difference sequence from subtractor 84 is provided to baseband filter 88 . Baseband filter 88 performs necessary filtering on the difference sequence and provides the filtered sequence to gain element 92 . Gain element 92 adjusts the gain of the signal and provides the gain to upconverter 96 . Upconverter 96 upconverts the gain adjusted signal in accordance with a QPSK modulation format and provides the unconverted signal to a first input of summer 100 .
[0061] The summing sequence from summer 86 is provided to baseband filter 90 . Baseband filter 90 performs necessary filtering on difference sequence and provides the filtered sequence to gain element 94 . Gain element 94 adjusts the gain of the signal and provides the gain to upconverter 98 . Upconverter 98 upconverts the gain adjusted signal in accordance with a QPSK modulation format and provides the upconverted signal to a second input of summer 100 . Summer 100 sums the two QPSK modulated signals and provides the result to transmitter 28 .
[0062] [0062]FIG. 3 illustrates four graphs of the average energy transmitted by transmitter 28 over a single frame for full rate 300 , half rate 302 , quarter rate 304 , and eighth rate transmissions 306 and 308 , respectively. As can be seen, for the full rate transmission 300 , the average energy is equal to some predetermined maximum level, E. For half rate transmission 302 , the average energy is equal to half the predetermined maximum level, or E/2. Likewise for quarter-rate transmission 304 , the average energy is equal to one-quarter of the predetermined maximum level, or E/4.
[0063] For the eighth-rate transmissions 306 and 308 , there are two possible transmit energies. The first transmission 306 uses continuous transmission at one-eighth of the predetermined maximum level, or E/8. The second transmission 308 (shown in dashed lines), uses a 50% duty cycle transmission at one-quarter of the predetermined maximum level, or E/4. In other words, the present invention provides two separate transmission schemes for the eighth-rate frames: a continuous transmission 306 at E/8, and a discontinuous transmission 308 at E/4. It should be noted that the discontinuous transmission 308 shown in FIG. 3 is merely exemplary. Other duty cycles and energy values are also contemplated by the present invention. For example, a 25% duty cycle at and energy of E/2 may be used in one embodiment. Another embodiment uses a 50% duty cycle with the transmission occurring in the first half of the frame, rather than the second half of the frame as shown in FIG. 3. In yet another embodiment, the transmission start time is randomized during the frame. However, even in the embodiments that do not randomize the transmission, the frame offset staggering in increments of 1.25 ms that is inherent to cdma2000 will distribute the aggregate interference well over a frame duration.
[0064] The amount of energy, timing, and duty cycle chosen are not limiting of the present invention. However, in the embodiment shown in FIG. 3, the transmission occurs during the second half of the frame so that power control can be the most accurate at the end of the frame in case the following frame is at a higher data rate. And hence more critical to control accurately since the higher data rate frames are transmitted at higher power and contain more information. Also in the embodiment of FIG. 1, the interleavers 6 and 18 and repetition generators 8 and 20 format the data such that transmitting only the second half of the frame ensures that each of the original information bits are transmitted at least once.
[0065] Control processor 36 controls the selection of whether the eighth-rate transmission is continuous or discontinuous. Variable rate data source 1 generates a rate indication to control processor 36 , informing the control processor 36 what the present data rate is. In response, control processor 36 determines whether to gate transmitter 28 on and off to implement the discontinuous transmission of the eighth-rate frames. In one embodiment of the present invention, control processor 36 instructs message generator 12 to generate a message for transmission to the base station over the control channel indicating that the wireless communication device 50 intends to operate in the discontinuous mode. In another embodiment, this message may be a request to operate in discontinuous mode, provided that the base station receiver can support discontinuous mode transmissions.
[0066] In one embodiment of the present invention, the control processor 36 may be programmed to always transmit eighth-rate frames according to the discontinuous mode shown as dashed line 308 of FIG. 3. In another embodiment, the control processor 36 may dynamically determine whether to transmit continuously or discontinuously according to the present transmit power of transmitter 28 . Since the AM interference caused by discontinuous transmission is proportional to the amplitude of the transmitted signal, the control processor 36 may compare the present transmit power to a predetermined threshold. If the transmit power is greater than the predetermined threshold, the control processor 36 does not gate the transmitter 28 , resulting in continuous transmission. If the transmit power is less than or equal to the predetermined threshold, the control processor 36 does gate the transmitter 28 , resulting in discontinuous transmission. In such an embodiment, the present transmit power may be determined by any means known in the art. For example, by measuring the output power of transmitter 28 with a conventional signal level detector circuit (not shown), or by accumulating power control commands from the base station, or by monitoring automatic gain control signals being sent to the transmitter 28 . Each of these power measurement techniques is well known in the art and will not be expanded upon herein.
[0067] In another embodiment of the present invention, the control processor 36 determines whether to transmit continuously or discontinuously according to user-defined preferences. For example, a menu option may be presented to a user on a graphical display (not shown), allowing the user to enable or disable discontinuous transmission. This embodiment would be particularly useful to persons using sensitive electronic equipment such as hearing aids and pacemakers to allow them to program their wireless communication device to always perform continuous transmission. This allows the user to make their own decision about the tradeoff between battery life and potentially dangerous AM interference. Still another embodiment allows discontinuous transmission during voice calls, and disables discontinuous transmission during data calls.
[0068] Typical wireless communication device power amplifiers use significant amounts of current. Also, other transmit signal processing components consume power. An example of the current consumption for various components in the transmitter 28 is shown in TABLE I below.
TABLE I Function Current (mA) Power Amplifier Bias Current 110-130 mA Power Amplifier Driver Current 42 mA DAC, filtering, upconverter, AGC 40 mA Total 202 mA
[0069] As can be seen from TABLE I above, approximately 202 mA of current may be switched out during discontinuous transmission in a typical wireless communication device. A typical variable rate data source 1 , during normal human speech, will produce eighth-rate frames about 63% of the time. So the potential average current savings for the example of TABLE I is about 63% eighth-rate frames*50% duty cycle*202 mA=64 mA. This is a significant amount of current savings in a typical wireless communication device where the total current consumption is approximately 320 mA at 100% duty cycle. In this example, discontinuous transmission of eighth-rate frames at a 50% duty cycle yields about a 25% increase in talk time.
[0070] In addition to the increase in talk time, a system capacity benefit is also realized by the present invention. As is known in the art, the strength of the reverse link pilot signal is driven primarily by the need to track the carrier phase and timing of the reverse link waveform. For most of the time during voice calls a typical wireless communication device is transmitting eighth-rate frames, and therefore is transmitting mostly pilot energy. By turning both the pilot and data signals off during low rate frames, the present invention enhances system capacity.
[0071] For example, if we assume that the required traffic component E b /N 0 is 1.6 dB per antenna at 9600 bps, 0.1 dB per antenna at 1500 bps, and the required pilot component E c /N 0 is −22.1 dB per antenna, we find the pilot power fraction shown below in TABLE II.
TABLE II Traffic Average Pilot Traffic Data Rate E b /N 0 (dB) E c /N 0 (dB) per (bps) per antenna antenna Pilot Power (%) 9600 1.6 −22 36% Continuous 1500 0.1 −22 86% 50% duty cycle 0.1 −25 76% 1500
[0072] Using the approximations shown above in TABLE II, gating the 1500 bps frames at the 50% duty cycle reduces the average voice call E c /N 0 by 0.85 dB for 8 kbps vocoder operation.
[0073] By operating at the exemplary 50% duty cycle for eighth-rate frames, the ability to maintain power control on the reverse link and forward link is affected. The update rate is reduced by a factor of two. For example, the update rate in a cdma2000 system may be reduced from 800 times per second to 400 times per second. This tends to cause an increase in the frame error rate for the eighth-rate frames. However, the increase in capacity and talk time gained by the present invention may outweigh this decrease in power control accuracy in many applications. Additionally, in one embodiment of the present invention, the transmit period (i.e., the time that the transmitter 28 is gated “on”) is arranged to occur at the end of the frame so that power control is most accurate at the frame boundary where the data rate may suddenly increase for the next frame.
[0074] Turning now to FIG. 4, a functional block diagram of selected portions of a base station 400 in accordance with the present invention. Reverse link RF signals from the wireless communication device 50 (FIG. 1) are received by receiver (RCVR) 402 , which downconverts the received reverse link RF signals to an baseband frequency. The baseband signal is then demodulated by demodulator 404 . Demodulator 404 is further described with reference to FIG. 5 below.
[0075] In the exemplary embodiment of FIG. 4, demodulator 404 has multiple outputs 405 A- 405 N, each corresponding to a different one of the logical channels modulated by modulator 26 of FIG. 1. For example, output 405 A corresponds to the control channel 42 of FIG. 1, and output 405 N corresponds to the fundamental channel 46 of FIG. 1. Demodulator 404 typically will have other demodulated signal outputs. However, for clarity and simplicity, only the control channel 405 A and fundamental channel 405 N are shown in FIG. 4.
[0076] The control channel 405 A data is de-interleaved by deinterleaver 406 , decoded by decoder 408 and CRC checked by CRC checker 410 . Each of these functional blocks 406 - 410 performs a complementary function as their counterparts in blocks 14 - 18 of FIG. 1. The control channel data is then passed to control processor 412 for further processing. For example, the control channel data may include a message from the wireless communication device 50 indicating that it either intends, or is requesting, to operate in discontinuous mode. In response to this message, control processor 412 directs message generator 424 (which includes forward link data formatting) to generate a reply message to the wireless communication device 50 , acknowledging reception of the intention or request message. The acknowledgment message is then modulated by modulator 422 and transmitted by transmitter (TMTR) 420 .
[0077] The fundamental channel 405 N is de-interleaved by deinterleaver 414 , decoded by decoder 416 and CRC checked by CRC checker 418 . Each of these functional blocks 414 - 418 performs a complementary function as their counterpart blocks 2 - 6 of FIG. 1. The fundamental channel data is then passed to other subsystems (not shown) in the base station 400 for further processing as required.
[0078] When control processor 412 receives a request message from wireless communication device 50 to operate in discontinuous mode, it configures deinterleavers 406 , 414 , decoders 408 , 416 , and CRC checkers 410 , 418 for operation in discontinuous mode. In one embodiment, this means that deinterleavers 406 , 414 , decoders 408 , 416 , and CRC checkers 410 , 418 ignore the portions of the frame that do not contain data.
[0079] Turning now to FIG. 5, an expanded functional block diagram of an exemplary single demodulation chain of demodulator 404 is shown. In the preferred embodiment, demodulator 404 has one demodulation chain for each information channel. The exemplary demodulator 404 of FIG. 5 performs complex demodulation on signals modulated by the exemplary modulator 26 of FIG. 1. As previously described, receiver (RCVR) 402 downconverts the received reverse link RF signals to a baseband frequency, producing I and Q baseband signals. Despreaders 502 and 504 respectively despread the I and Q baseband signals using the long code from FIG. 1. Baseband filters (BBF) 506 and 508 respectively filter the I and Q baseband signals.
[0080] Despreaders 510 and 512 respectively despread the I and Q signals using the PN I sequence of FIG. 2. Similarly, despreaders 514 and 516 respectively despread the Q and I signals using the PN Q sequence of FIG. 2. The outputs of despreaders 510 and 512 are combined in combiner 518 . The output of despreader 516 is subtracted from the output of despreader 512 in combiner 520 .
[0081] The respective outputs of combiners 518 and 520 are then Walsh-uncovered in Walsh-uncoverers 522 and 524 with the Walsh code that was used to cover the particular channel of interest in FIG. 2. The respective outputs of the Walsh-uncoverers 522 and 524 are then summed over one Walsh symbol by accumulators 530 and 532 .
[0082] The respective outputs of combiners 518 and 520 are also summed over one Walsh symbol by accumulators 526 and 528 . The respective outputs of accumulators 526 and 528 are then applied to pilot filters 534 and 536 . Pilot filters 534 and 536 generate an estimation of the channel conditions by determining the estimated gain and phase of the pilot signal data 40 (see FIG. 1). The output of pilot filter 534 is then complex multiplied by the respective outputs of accumulators 530 and 532 in complex multipliers 538 and 540 . Similarly, the output of pilot filter 536 is complex multiplied by the respective outputs of accumulators 530 and 532 in complex multipliers 542 and 544 . The output of complex multiplier 542 is then summed with the output of complex multiplier 538 in combiner 546 . The output of complex multiplier 544 is subtracted from the output of complex multiplier 540 in combiner 548 . Finally, the outputs of combiners 546 and 548 are combined in combiner 550 to produce the demodulated signal of interest 405 .
[0083] Of particular interest to the present invention are pilot filters 534 and 536 . In order to obtain a more accurate estimate of the pilot phase and gain during reception of discontinuous transmissions, the present invention preferably uses a pilot filter that accounts for the 180-degree phase shift at the boundary between continuous and discontinuous transmission in any frame. For example, in the 50% duty cycle transmission 308 (FIG. 3), the pilot filter account for the phase change that occurs at time T/2 in each frame of length T.
[0084] One embodiment of the present invention utilizes a “sliding” filter window in combination with a “blocked” filter window in order to avoid improper pilot estimation at the discontinuity boundary. The “blocked” filter is used to estimate the pilot gain and phase immediately before and after any discontinuities in the frame. The “sliding” filter is used to estimate the pilot gain and phase during the remainder of the frame. An exemplary pilot filter that uses a sliding window estimator 600 in combination with a block window estimator 612 is shown in FIG. 6.
[0085] In FIG. 6, the output of either accumulator 526 of 528 is applied to shift register 602 , and is also fed forward to combiner 604 . In the exemplary embodiment, shift register 602 is a twelve-stage shift register. The shifted output of shift register 602 is subtracted from the fed-forward input in combiner 604 and provided to combiner 606 . The output of combiner 606 is delayed in delay element 608 and fed back to be combined with the output of combiner 604 in combiner 606 . The output of delay element 608 is also provided to truncator 610 where it is truncated to be 11 bits, and provided as one selectable input to multiplexer 614 . This input to multiplexer 614 represents the sliding window estimate of the pilot phase and gain.
[0086] The output of either accumulator 526 or 528 is also provided to block window estimator 612 which simply accumulates the signal over a predetermined period and provides an output representing the block window estimate of the pilot phase and gain as a second selectable input to multiplexer 614 .
[0087] Multiplexer 614 is controlled by a select signal from control processor 412 which selects between the sliding window estimate and the block window estimate inputs when operating in the discontinuous transmit mode. During a predetermined period immediately before and after any discontinuity, control processor 412 selects the block window estimate from multiplexer 614 . At other times during the frame, control processor 412 selects the sliding window estimate from multiplexer 614 . The output of multiplexer 614 is then applied to either complex multipliers 538 and 540 or 542 and 544 as shown in FIG. 5.
[0088] A slightly different embodiment of the pilot filters 534 , 536 implements a sliding window equal taps FIR filter of 2.5 ms in length. However, due to the phase discontinuity boundaries caused by discontinuous transmission, the, window size is reduced immediately before and after each phase discontinuity boundary to smooth the effect of the phase discontinuity. The filter is updated at the modulation symbol rate which in the exemplary embodiment is one update every two chips. This results in the corresponding phase estimate output also having a two chip resolution. The minimum window size is preferably 1.25 ms, and the window size grows symbol by symbol until it reaches the sliding window buffer size of 2.5 ms. Other embodiments may use combinations of the techniques described above to account for the phase discontinuity boundaries inherent in discontinuous transmission.
[0089] [0089]FIG. 7 shows the apparatus of the final aspect of present invention. A Code Division Multiple Access (CDMA)—mobile station 700 includes a symbol source 702 , an interleaver 704 , and a transmitter 706 . The symbol source 702 may be a conventional microphone and vocoder.
[0090] The interleaver 704 is connected to receive symbols from the symbol source 702 , and is constructed to interleave them within a frame. The transmitter 706 is connected to receive the frame of interleaved symbols, and is constructed to transmit it.
[0091] The apparatus further includes a gate 708 constructed to disable transmission during a fraction F of the frame. The interleaver 704 is constructed to repeat each symbol at least 1/F times. The gate 708 of FIG. 7 is shown as connected directly to the transmitter 706 . It could alternatively fractionally disable transmission by manipulating the interleaver 704 . This alternative structure is more complicated and is not preferred.
[0092] Preferably, F=1/2, so the interleaver 704 repeats each symbol at least twice (and preferable more times) in the frame. Thus, even though half of the frame is not transmitted, at least one copy (and preferably more copies) of each symbol is transmitted in each frame.
[0093] It is better for the gate 708 to be constructed to disable the transmitter 706 during the first half of the frame rather than the second half. If the transmitted portion of the frame occurs later in the frame, then the mobile station can better estimate the difference between the measured and expected forward signal to noise ratio.
[0094] The conventional mobile station 700 includes a frame rate indicator 710 , which produces an indication as to how fast the mobile station 700 is transmitting. This indication is useful for many purposes. In the present invention, it is applied to a selector 712 . The selector 712 is connected to receive the frame rate indication from the frame rate indicator 710 . It is also constructed to selectively enable the gate 708 in response to the frame rate indication. That is, it selectively instructs the gate 708 to turn off the transmitter 706 during the first half of the frame (enables the gate), or instructs the gate 708 to leave the transmitter 706 on for the entire frame (disables the gate).
[0095] If desired, the selector 712 may include an adjustment mechanism 714 constructed to enable the gate for all frame rate indications. This is desirable if the mobile station is used in an area where capacity is limited. However, this gating on-and off produces interference in the audio band. When it is important to reduce audio interference, the adjustment mechanism 714 may be constructed to disable the gate for all frame rate indications. Preferably, however, the adjustment mechanism 714 is constructed to enable the gate for a first predetermined set of frame rate indications 716 , and to disable the gate for a second predetermined set of frame rate indications 718 .
[0096] The apparatus may also include a mode commander 720 , constructed to command a mode in which transmission of frames is enabled only when one of the first (generally slower) predetermined set of frame rate indications is applied to the mode commander 720 . That is, the transmitter 706 is disabled—for the entire frame, and not just for its first half—for the second (generally faster) set of frame rates. Thus, the transmitter 706 is disabled for the first half of every frame (and also for the second half of some of the frames). This permits a receiver retuner 722 to be connected to receive a mode command from the mode commander 720 . It is constructed to retune a receiver, when so commanded by the mode commander 720 , during the fraction of the frame (the first half) during which transmission is disabled.
[0097] The conventional mobile station 700 includes a power indicator 724 , which indicates the power at which the mobile station 700 is transmitting. The present invention uses this by connecting the selector 712 to receive a power indication from the power indicator 724 . The selector 712 is then constructed to selectively enable the gate 708 depending on both the frame rate indication and the power indication.
[0098] [0098]FIG. 8 shows the method of operation 800 of the final aspect of the present invention. The present invention may thus be viewed as a method 800 for operating a Code Division Multiple Access (CDMA) mobile station. The conventional method includes providing a sequence of symbols 802 , interleaving each symbol within a frame 804 , and transmitting the frame of interleaved symbols 806 . To this, the present invention adds disabling transmission during a fraction F of the frame 808 . The interleaving 804 thus must include repeating each symbol at least 1/F times. As before, preferably F=1/2, and preferably the fractional disabling of the frame transmission takes place during the first half of the frame.
[0099] The fractional disabling of the frame transmission is selective in response to a frame rate indication 810 . The selective fractional disabling 808 may include fractionally disabling the frame transmission at all frame rate indications 812 , or may fractionally disable the frame transmission at no frame rate indication 814 .
[0100] The selective fractional disabling 808 may include fractionally disabling the frame transmission for a first predetermined set of frame rate indications, and excludes fractionally disabling the frame transmission for a second predetermined set of frame rate indications. The method may further include commanding a mode 816 in which transmission of frames is enabled only for the first predetermined set of frame rate indications. In this case, it also includes retuning a receiver 818 , when the mode is so commanded, during the fraction of the frame during which transmission is disabled.
[0101] The selective fractional disabling may also include fractionally disabling the frame transmission depending on both the frame rate indication 810 and a power indication 820 .
[0102] Thus, the present invention provides a method and apparatus for transmit gating in a wireless communication system which allows the wireless communication device to operate either in continuous or discontinuous transmit modes.
[0103] The previous description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. The various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
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A method and system for communicating a frame of information according to both a continuous transmit format and a discontinuous transmit format. The present invention contemplates transmitting one or more data rates in either a continuous transmit mode ( 814 ) or a discontinuous transmit mode ( 812 ). The present invention contemplates continuous transmission only for certain data rates, and selection between continuous and discontinuous transmission for other data rates ( 810 ). Frames transmitted in the discontinuous transmit mode may be transmitted at a higher transmit power than in the continuous transmit mode ( 820 ). In one embodiment, the information is transmitted at a fifty-percent duty cycle during the second half of the frame when in the discontinuous transmit mode ( 808 ). During periods of non-transmission, an alternative system may be searched for as a possible candidate for hard handoff ( 816 ).
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RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 14/222,939 entitled “SYSTEM AND METHOD FOR EXECUTION OF A SECURED ENVIRONMENT INITIALIZATION INSTRUCTION” filed on Mar. 24, 2014. Ser. No. 14/222,939 is a Continuation of U.S. patent application Ser. No. 13/835,997 filed on Mar. 15, 2013 entitled “SYSTEM AND METHOD FOR EXECUTION OF A SECURED ENVIRONMENT INITIALIZATION INSTRUCTION”. Ser. No. 13/835,997 is a Continuation of U.S. patent application Ser. No. 13/444,450, entitled “SYSTEM AND METHOD FOR EXECUTION OF A SECURED ENVIRONMENT INITIALIZATION INSTRUCTION” filed on Apr. 11, 2012, which is a continuation of U.S. patent application Ser. No. 12/455,844, filed on Jun. 8, 2009, entitled “SYSTEM AND METHOD FOR EXECUTION OF A SECURED ENVIRONMENT INITIALIZATION INSTRUCTION” which issued on Jun. 9, 2009, as U.S. Pat. No. 8,185,734, which is a continuation of U.S. patent application Ser. No. 11/096,618, filed on Mar. 31, 2005, entitled “SYSTEM AND METHOD FOR EXECUTION OF A SECURED ENVIRONMENT INITIALIZATION INSTRUCTION” which issued on Jun. 9, 2009, as U.S. Pat. No. 7,546,457, is a continuation of U.S. patent application Ser. No. 10/112,169, filed on Mar. 29, 2002, entitled “SYSTEM AND METHOD FOR EXECUTION OF A SECURED ENVIRONMENT INITIALIZATION INSTRUCTION” which issued on Jun. 27, 2006, as U.S. Pat. No. 7,069,442.
FIELD
[0002] The present invention relates generally to microprocessor systems, and more specifically to microprocessor systems that may operate in a trusted or secured environment.
BACKGROUND
[0003] The increasing number of financial and personal transactions being performed on local or remote microcomputers has given impetus for the establishment of “trusted” or “secured” microprocessor environments. The problem these environments try to solve is that of loss of privacy, or data being corrupted or abused. Users do not want their private data made public. They also do not want their data altered or used in inappropriate transactions. Examples of these include unintentional release of medical records or electronic theft of funds from an on-line bank or other depository. Similarly, content providers seek to protect digital content (for example, music, other audio, video, or other types of data in general) from being copied without authorization.
[0004] Existing trusted systems may utilize a complete closed set of trusted software. This method is relatively simple to implement, but has the disadvantage of not allowing the simultaneous use of common, commercially available operating system and application software. This disadvantage limits the acceptance of such a trusted system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
[0006] FIG. 1 is a diagram of an exemplary software environment executing in a microprocessor system.
[0007] FIG. 2 is a diagram of certain exemplary trusted or secured software modules and exemplary system environment, according to one embodiment of the present invention.
[0008] FIG. 3 is a diagram of an exemplary trusted or secured software environment, according to one embodiment of the present invention.
[0009] FIG. 4A is a schematic diagram of an exemplary microprocessor system adapted to support the secured software environment of FIG. 3 , according to one embodiment of the present invention.
[0010] FIG. 4B is a schematic diagram of an exemplary microprocessor system adapted to support the secured software environment of FIG. 3 , according to an alternate embodiment of the present invention.
[0011] FIG. 5 is a schematic diagram of an exemplary microprocessor system adapted to support the secured software environment of FIG. 3 , according to an alternate embodiment of the present invention.
[0012] FIG. 6 is a time line drawing of the execution of software components, according to one embodiment of the present invention.
[0013] FIG. 7 is a flowchart of software and other process blocks, according to one embodiment of the present invention.
DETAILED DESCRIPTION
[0014] The following description describes techniques for initiating a trusted or secured environment in a microprocessor system. In the following description, numerous specific details such as logic implementations, software module allocation, encryption techniques, bus signaling techniques, and details of operation are set forth in order to provide a more thorough understanding of the present invention. It will be appreciated, however, by one skilled in the art that the invention may be practiced without such specific details. In other instances, control structures, gate level circuits and full software instruction sequences have not been shown in detail in order not to obscure the invention. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation. The invention is disclosed in the form of a microprocessor system. However, the invention may be practiced in other forms of processor such as a digital signal processor, a minicomputer, or a mainframe computer.
[0015] Referring now to FIG. 1 , a diagram of an exemplary software environment executing in a microprocessor system is shown. The software shown in FIG. 1 is not trusted (untrusted). When operating in a high privilege level, the size and constant updating of the operating system 150 make it very difficult to perform any trust analysis in a timely manner. Much of the operating system sits within privilege ring zero ( 0 ), the highest level of privilege. The applications 152 , 154 , and 156 have much reduced privilege and typically reside within privilege ring three ( 3 ). The existence of the differing privilege rings and the separation of the operating system 150 and applications 152 , 154 and 156 into these differing privileged rings would appear to allow operating of the software of FIG. 1 in a trusted mode, based on making a decision to trust the facilities provided by the operating system 150 . However, in practice making such a trust decision is often impractical. Factors that contribute to this problem include the size (number of lines of code) of the operating system 150 , the fact that the operating system 150 may be the recipient of numerous updates (new code modules and patches) and the fact that the operating system 150 may also contain code modules such as device drivers supplied by parties other than the operating system developer. Operating system 150 may be a common one such as Microsoft® Windows®, Linux, or Solaris®, or may be any other appropriate known or otherwise available operating system. The particular types or names of applications or operating systems run or running are not critical.
[0016] Referring now to FIG. 2 , a diagram of certain exemplary trusted or secured software modules and exemplary system environment 200 is shown, according to one embodiment of the present invention. In the FIG. 2 embodiment, processor 202 , processor 212 , processor 222 , and optional other processors (not shown) are shown as separate hardware entities. In other embodiments, the number of processors may differ, as may the boundary of various components and functional units. In some embodiments the processors may be replaced by separate hardware execution threads or “logical processors” running on one or more physical processors.
[0017] Processors 202 , 212 , 222 may contain certain special circuits or logic elements to support secure or trusted operations. For example, processor 202 may contain secure enter (SENTER) logic 204 to support the execution of special SENTER instructions that may initiate trusted operations. Processor 202 may also contain bus message logic 206 to support special bus messages on system bus 230 in support of special SENTER operations. In alternate embodiments, memory control functions of chipset 240 may be allocated to circuits within the processors, and for multiple processors may be included on a single die. In these embodiments, special bus messages may also be sent on busses internal to the processors. The use of special bus messages may increase the security or trustability of the system for several reasons. Circuit elements such as processors 202 , 212 , and 222 or chipset 240 may only issue or respond to such messages if they contain the appropriate logic elements of embodiments of the present disclosure. Therefore successful exchange of the special bus messages may help ensure proper system configuration. Special bus messages may also permit activities that should normally be prohibited, such as resetting a platform configuration register 278 . The ability of potentially hostile untrusted code to spy on certain bus transactions may be curtailed by allowing special bus messages to be issued only in response to special security instructions.
[0018] Additionally, processor 202 may contain secure memory 208 to support secure initialization operations. In one embodiment secure memory 208 may be an internal cache of processor 202 , perhaps operating in a special mode. In alternate embodiments secure memory 208 may be special memory. Other processors such as processor 212 and processor 222 may also include SENTER logic 214 , 224 , bus message logic 216 , 226 , and secure memory 218 , 228 .
[0019] A “chipset” may be defined as a group of circuits and logic that support memory and input/output (I/O) operations for a connected processor or processors. Individual elements of a chipset may be grouped together on a single chip, a pair of chips, or dispersed among multiple chips, including processors. In the FIG. 2 embodiment, chipset 240 may include circuitry and logic to support memory and I/O operations to support processors 202 , 212 , and 222 . In one embodiment, chipset 240 may interface with a number of memory pages 250 through 262 and a device-access page table 248 containing control information indicating whether non-processor devices may access the memory pages 250 through 262 . Chipset 240 may include device-access logic 247 that may permit or deny direct memory access (DMA) from I/O devices to selected portions of the memory pages 250 through 262 . In some embodiment the device access logic 247 may contain all relevant information required to permit or deny such accesses. In other embodiments, the device access logic 247 may access such information held in the device access page table 248 . The actual number of memory pages is not important and will change depending upon system requirements. In other embodiments the memory access functions may be external to chipset 240 . The functions of chipset 240 may further be allocated among one or more physical devices in alternate embodiments.
[0020] Chipset 240 may additionally include its own bus message logic 242 to support special bus messages on system bus 230 in support of special SENTER operations. Some of these special bus messages may include transferring the contents of a key register 244 to a processor 202 , 212 , or 222 , or permitting a special ALL_JOINED flag 274 to be examined by a processor 202 , 212 , or 222 . Additional features of the bus message logic 242 may be to register bus activity by processors in an “EXISTS” register 272 and store certain special bus message activity by processors in a “JOINS” register 272 . Equality of contents of EXISTS register 272 and JOINS register 272 may be used to set the special ALL_JOINED flag 274 to indicate all processors in the system are participating in the secure enter process.
[0021] Chipset 240 may support standard I/O operations on I/O busses such as peripheral component interconnect (PCI), accelerated graphics port (AGP), universal serial bus (USB), low pin count (LPC) bus, or any other kind of I/O bus (not shown). An interface 290 may be used to connect chipset 240 with token 276 , containing one or more platform configuration registers (PCR) 278 , 279 . In one embodiment, interface 290 may be the LPC bus (Low Pin Count (LPC) Interface Specification, Intel Corporation, rev. 1.0, 29 December 1997) modified with the addition of certain security enhancements. One example of such a security enhancement would be a locality confirming message, utilizing a previously-reserved message header and address information targeting a platform configuration register (PCR) 278 within token 276 . In one embodiment, token 276 may contain special security features, and in one embodiment may include the trusted platform module (TPM) 281 disclosed in the Trusted Computing Platform Alliance (TCPA) Main Specification, version 1.1a, 1 December 2001, issued by the TCPA (available at the time of filing of the present application at www.trustedpc.com).
[0022] Two software components identified in system environment 200 are a Secure Virtual Machine Monitor (SVMM) 282 module and a Secure Initialization Authenticated Code (SINIT-AC) 280 module. The SVMM 282 module may be stored on a system disk or other mass storage, and moved or copied to other locations as necessary. In one embodiment, prior to beginning the secure launch process SVMM 282 may be moved or copied to one or more memory pages 250 through 262 . Following the secure enter process, a virtual machine environment may be created in which the SVMM 282 may operate as the most privileged code within the system, and may be used to permit or deny direct access to certain system resources by the operating system or applications within the created virtual machines.
[0023] Some of the actions required by the secure enter process may be beyond the scope of simple hardware implementations, and may instead advantageously use a software module whose execution can be implicitly trusted. In one embodiment, these actions may be performed by Secure Initialization (SINIT) code. Three exemplary actions are identified here, but these actions should not be taken to be limiting. One action may require that various controls representing critical portions of the system configuration be tested to ensure that the configuration supports the correct instantiation of the secure environment. In one embodiment, one required test may be that the memory controller configuration provided by chipset 240 does not permit two or more different system bus addresses to touch the same location within memory pages 250 through 262 . A second action may be to configure the device-access page table 248 and device-access logic 247 to protect those memory pages used by the memory-resident copy of SVMM 282 from interference by non-processor devices. A third action may be to calculate and register the SVMM 282 module's identity and transfer system control to it. Here “register” means placing a trust measurement of SVMM 282 into a register, for example into PCR 278 or into PCR 279 . When this last action is taken, the trustworthiness of the SVMM 282 may be inspected by a potential system user.
[0024] The SINIT code may be produced by the manufacturer of the processors or of the chipsets. For this reason, the SINIT code may be trusted to aid in the secure launch of chipset 240 . In order to distribute the SINIT code, in one embodiment a well-known cryptographic hash is made of the entire SINIT code, producing a value known as a “digest”. One embodiment produces a 160-bit value for the digest. The digest may then be encrypted by a private key, held in one embodiment by the manufacturer of the processor, to form a digital signature. When the SINIT code is bundled with the corresponding digital signature, the combination may be referred to as SINIT authenticated code (SINIT-AC) 280 . Copies of the SINIT-AC 280 may be later validated as discussed below.
[0025] The SINIT-AC 280 may be stored on system disk or other mass storage or in a fixed media, and moved or copied to other locations as necessary. In one embodiment, prior to beginning the secure launch process SINIT-AC 280 may be moved or copied into memory pages 250 - 262 to form a memory-resident copy of SINIT-AC.
[0026] Any logical processor may initiate the secure launch process, and may then be referred to as the initiating logical processor (ILP). In the present example processor 202 becomes the ILP, although any of the processors on system bus 230 could become the ILP. Neither memory-resident copy of SINIT-AC 280 nor memory-resident copy of SVMM 282 may be considered trustworthy at this time since, among other reasons, the other processors or the DMA devices may overwrite memory pages 250 - 262 .
[0027] The ILP (processor 202 ) then executes a special instruction. This special instruction may be referred to as a secured enter (SENTER) instruction, and may be supported by SENTER logic 204 . Execution of the SENTER instruction may cause the ILP (processor 202 ) to issue special bus messages on system bus 230 , and then wait considerable time intervals for subsequent system actions. After execution of SENTER begins, one of these special bus messages, SENTER BUS MESSAGE, is broadcast on system bus 230 . Those logical processors other than the ILP, which may be referred to as responding logical processors (RLPs), respond to the SENTER BUS MESSAGE with an internal non-maskable event. In the present example, the RLPs include processor 212 and processor 222 . The RLPs must each terminate current operations, send a RLP acknowledge (ACK) special bus message on system bus 230 , and then enter a wait state. It should be noted that the ILP also sends its own ACK message over system bus 230 .
[0028] The chipset 240 may contain a pair of registers, “EXISTS” register 270 and “JOINS” register 272 . These registers may be used to verify that the ILP and all of the RLPs are responding properly to the SENTER BUS MESSAGE. In one embodiment, chipset 240 may keep track of all operational logical processors in the system by writing a “1” into the corresponding bit of the EXISTS register 270 on any system bus transaction made by that logical processor. In this embodiment, each transaction on system bus 230 must contain an identification field containing the logical processor identifier. In one embodiment, this consists of a physical processor identifier and an identifier for the hardware execution thread within each physical processor. For example, if a thread executing on processor 222 caused any bus transactions on system bus 230 , chipset 240 would see this logical processor identifier within the transaction and write a “1” into the corresponding location 286 within EXISTS register 270 . During the secure launch process, when that same thread on processor 222 sends its ACK message on system bus 230 , the chipset 240 would also see this and could write a “1” into the corresponding location 288 in the JOINS register 272 . (In the FIG. 2 example, each physical processor is shown with only a single thread executing for clarity. In alternate embodiments the physical processors may support multiple threads, and thereby multiple logical processors.) When the contents of the JOINS register 272 matches the contents of the EXISTS register 270 , then chipset 240 can set an ALL_JOINED flag 246 indicating that all processors have properly responded to the SENTER BUS MESSAGE.
[0029] In another embodiment, EXISTS register 270 and JOINS register 272 may continue to aid security subsequent to the setting of the ALL_JOINED flag 246 . During the time subsequent to the setting of the ALL_JOINED flag 246 until the end of trusted or secure operations, chipset 240 may continue to monitor and compare bus cycles_against the JOINS register 272 . During this period, if chipset 240 ever sees a bus transaction from a logical processor that is not currently identified in JOINS register 272 , then chipset 240 may presume that this logical processor has somehow “appeared” late. This would imply that such a logical processor did not participate in the secure launch process, and therefore could represent an attacker (security threat). In such circumstances, chipset 240 may respond appropriately to keep this attacker out of the secured environment. In one embodiment, chipset 240 may force a system reset in such circumstances. In a second embodiment, similar detection of a “late” processor may be achieved by each logical processor asserting a special reserved signal on the system bus on every transaction following the assertion of the ACK bus message. In this embodiment, following the setting of the ALL_JOINED flag 246 if the chipset 240 observes a bus transaction initiated by a processor without the special signal asserted, then chipset 240 may again presume that this logical processor has somehow appeared “late”, and may represent an attacker.
[0030] After issuing the SENTER BUS MESSAGE, the ILP (processor 202 ) polls the ALL_JOINED flag 246 to see when and if all processors have properly responded with their ACKs. If the flag 246 is never set, several implementations are possible. A watchdog timer in the ILP or chipset or elsewhere may cause a system reset. Alternatively, the system may hang requiring operator reset. In either case the assertion of a secure environment is protected (in that the secure launch process does not complete unless all processors participate), although the system may not continue to function. In normal operations, after a short time the ALL_JOINED flag 246 is set, and the ILP may be assured that all other logical processors have entered a wait state.
[0031] When the ALL_JOINED flag 246 is set, the ILP (processor 202 ) may move both a copy of SINIT-AC 280 and key 284 into secure memory 208 for the purpose of authenticating and subsequently executing the SINIT code included in SINIT-AC 280 . In one embodiment, this secure memory 208 may be an internal cache of the ILP (processor 202 ), perhaps operating in a special mode. Key 284 represents the public key corresponding to the private key used to encrypt the digital signature included in the SINIT-AC 280 module, and is used to verify the digital signature and thereby authenticate the SINIT code. In one embodiment, key 284 may already be stored in the processor, perhaps as part of the SENTER logic 204 . In another embodiment, key 284 may be stored in a read-only key register 244 of chipset 240 , which is read by the ILP. In yet another embodiment, either the processor or the chipset's key register 244 may actually hold a cryptographic digest of key 284 , where key 284 itself is included in the SINIT-AC 280 module. In this last embodiment, the ILP reads the digest from key register 244 , calculates an equivalent cryptographic hash over the key 284 embedded in SINIT-AC 280 , and compares the two digests to ensure the supplied key 284 is indeed trusted.
[0032] A copy of SINIT-AC and a copy of a public key may then exist within secure memory 208 . The ILP may now validate the copy of SINIT-AC by decrypting the digital signature included in the copy of the SINIT-AC using the copy of a public key. This decryption produces an original copy of a cryptographic hash's digest. If a newly-calculated digest matches this original digest then the copy of SINIT-AC and its included SINIT code may be considered trustable.
[0033] The ILP may now issue another special bus message, SENTER CONTINUE MESSAGE, via system bus 230 signaling the waiting RLP's (processor 212 , processor 222 ) and chipset 240 that secured operations are going to be initiated. The ILP may now register the unique identity of the SINIT-AC module by writing the SINIT-AC module's cryptographic digest value to a platform configuration register 272 in the security token 276 , as outlined below. The ILP's execution of its SENTER instruction may now terminate by transferring execution control to the trusted copy of the SINIT code held within the ILP's secure memory 208 . The trusted SINIT code may then perform its system test and configuration actions and may register the memory-resident copy of SVMM, in accordance with the definition of “register” above.
[0034] Registration of the memory-resident copy of SVMM may be performed in several manners. In one embodiment, the SENTER instruction running on the ILP writes the calculated digest of SINIT-AC into PCR 278 within the security token 276 . Subsequently, the trusted SINIT code may write the calculated digest of the memory-resident SVMM to the same PCR 278 or another PCR 279 within the security token 276 . If the SVMM digest is written to the same PCR 278 , the security token 276 hashes the original contents (SINIT digest) with the new value (SVMM digest) and writes the result back into the PCR 278 . In embodiments where the first (initializing) write to PCR 278 is limited to the SENTER instruction, the resulting digest may be used as a root of trust for the system.
[0035] Once the trusted SINIT code has completed its execution, and has registered the identity of the SVMM in a PCR, the SINIT code may transfer ILP execution control to the SVMM. In a typical embodiment, the first SVMM instructions executed by the ILP may represent a self-initialization routine for the SVMM. The ILP may in one embodiment issue individual RLP JOIN MESSAGE special bus messages to each RLP, causing each of the RLPs to join in operations under the supervision of the now-executing copy of SVMM. From this point onwards, the overall system is operating in trusted mode as outlined in the discussion of FIG. 3 below.
[0036] Referring now to FIG. 3 , a diagram of an exemplary trusted or secured software environment is shown, according to one embodiment of the present invention. In the FIG. 3 embodiment, trusted and untrusted software may be loaded simultaneously and may execute simultaneously on a single computer system. A SVMM 350 selectively permits or prevents direct access to hardware resources 380 from one or more untrusted operating systems 340 and untrusted applications 310 through 330 . In this context, “untrusted” does not necessarily mean that the operating system or applications are deliberately misbehaving, but that the size and variety of interacting code makes it impractical to reliably assert that the software is behaving as desired, and that there are no viruses or other foreign code interfering with its execution. In a typical embodiment, the untrusted code might consist of the normal operating system and applications found on today's personal computers.
[0037] SVMM 350 also selectively permits or prevents direct access to hardware resources 380 from one or more trusted or secure kernels 360 and one or more trusted applications 370 . Such a trusted or secure kernel 360 and trusted applications 370 may be limited in size and functionality to aid in the ability to perform trust analysis upon it. The trusted application 370 may be any software code, program, routine, or set of routines which is executable in a secure environment. Thus, the trusted application 370 may be a variety of applications, or code sequences, or may be a relatively small application such as a Java applet.
[0038] Instructions or operations normally performed by operating system 340 or kernel 360 that could alter system resource protections or privileges may be trapped by SVMM 350 , and selectively permitted, partially permitted, or rejected. As an example, in a typical embodiment, instructions that change the processor's page table that would normally be performed by operating system 340 or kernel 360 would instead be trapped by SVMM 350 , which would ensure that the request was not attempting to change page privileges outside the domain of its virtual machine.
[0039] Referring now to FIG. 4A , one embodiment of a microprocessor system 400 adapted to support the secured software environment of FIG. 3 is shown. CPU A 410 , CPU B 414 , CPU C 418 , and CPU D 422 may be configured with additional microcode or logic circuitry to support the execution of special instructions. In one embodiment, this additional microcode or logic circuitry may be the SENTER logic 204 of FIG. 2 . These special instructions may support the issuance of special bus messages on system bus 420 that may enable the proper synchronization of the processors while launching the secure environment. In one embodiment, the issuance of special bus messages may be supported by circuitry such as the bus message logic 206 of FIG. 2 . Similarly chipset 430 may be similar to chipset 240 and may support the above-mentioned special cycles on system bus 420 . The number of physical processors may vary upon the implementation of a particular embodiment. In one embodiment, the processors may be Intel® Pentium® class microprocessors. Chipset 430 may interface with mass storage devices such as fixed media 444 or removable media 448 via PCI bus 446 , or, alternately, via USB 442 , an integrated controller electronics (IDE) bus (not shown), a small computer systems interconnect (SCSI) bus (not shown), or any other I/O busses. The fixed media 444 or removable media 448 may be magnetic disks, magnetic tape, magnetic diskettes, magneto-optical drives, CD-ROM, DVD-ROM, Flash memory cards, or many other forms of mass storage.
[0040] In the FIG. 4A embodiment, the four processors CPU A 410 , CPU B 414 , CPU C 418 , and CPU D 422 are shown as four separate hardware entities. In other embodiments, the number of processors may differ. Indeed, the physically discrete processors may be replaced by separate hardware execution threads running on one or more physical processors. In the latter case these threads possess many of the attributes of additional physical processors. In order to have a generic expression to discuss using any mixture of multiple physical processors and multiple threads upon processors, the expression “logical processor” may be used to describe either a physical processor or a thread operating in one or more physical processors. Thus, one single-threaded processor may be considered a logical processor, and multi-threaded or multi-core processors may be considered multiple logical processors.
[0041] In one embodiment, chipset 430 interfaces with a modified LPC bus 450 . Modified LPC bus 450 may be used to connect chipset 430 with a security token 454 . Token 454 may in one embodiment include the TPM 471 envisioned by the Trusted Computing Platform Alliance (TCPA).
[0042] Referring now to FIG. 4B , an alternate embodiment of a microprocessor system 490 adapted to support the secured software environment of FIG. 3 is shown. Differing from the FIG. 4A embodiment, CPU A 410 and CPU B 414 may be connected to chipset 428 with system bus A 402 whereas CPU C 418 and CPU D 422 may be connected to chipset 428 with system bus B 404 . In other embodiments more than two system busses may be utilized. In another alternative embodiment, point-to-point busses may be used. Special instructions may support the issuance of special bus messages on system bus A 402 and system bus B 404 that may enable the proper synchronization of the processors while launching the secure environment. In one embodiment, the issuance of special bus messages may be supported by circuitry such as the bus message logic 206 of FIG. 2 .
[0043] In one embodiment, chipset 428 is responsible for maintaining consistency and coherency across system bus A 402 and system bus B 404 . If a bus message, standard or special, is sent across system bus A 402 , chipset 428 reflects that message (when appropriate) onto system bus B 404 , and vice-versa.
[0044] In an alternate embodiment, chipset 428 treats system bus A 402 and system bus B 404 as independent subsystems. Any special bus messages issued on system bus A 402 apply only to processors on that bus: similarly, special bus messages issued on system bus B 404 apply only to processors on that bus. Any protected memory that is established with respect to system bus A 402 is only accessible to processors connected to system bus A 402 , and the processors on system bus B 404 may be treated as untrusted devices. To gain access to any protected memory established for CPU A 410 and CPU B 414 on system bus A 402 , processors CPU C 418 and CPU D 422 on system bus B 404 must perform their own SENTER process, creating a registered environment equal to that created for the processors on system bus A 402 .
[0045] Referring now to FIG. 5 , a schematic diagram of an exemplary microprocessor system 500 adapted to support the secured software environment of FIG. 3 is shown, according to an alternate embodiment of the present invention. Differing from the FIG. 4A embodiment, each processor (for example, CPU A 510 ) may include certain chipset functions (for example, chipset functions 593 ) that, for example, perform memory controller functions and device access logic functions. These chipset functions thereby allow the direct connection of memory (for example, memory A 502 ) to the processor. Other chipset functions may remain in a separate chipset 530 . Special bus messages may be issued across system bus 520 .
[0046] Each processor may make indirect accesses to memory connected to other processors: however, these accesses may be considerably slower when compared to accesses to a processor's own memory. Prior to the start of the SENTER process, software may move copies of SINIT-AC 566 and SVMM 574 from fixed media 544 into local memory 504 , forming copy of SINIT-AC 556 and copy of SVMM 572 . In one embodiment, the memory 504 may be selected because it is directly accessed by the processor intended to be the ILP, in the FIG. 5 example this is CPU B 514 . Alternatively, the SINIT-AC 566 and SVMM 574 copies may be placed in other memories attached to other (non-ILP) processors, so long as the ILP 514 has the ability to access those memories. CPU B ILP 514 begins the secure enter process by issuing the SENTER instruction, as already described in FIG. 2 , and with similar consequences and bus cycles issued. Chipset 530 may utilize EXISTS register 576 , JOINS register 580 , and ALL_JOINED flag 584 as described above in connection with FIG. 2 to determine whether all processors have properly responded to the SENTER BUS MESSAGE and signal this information to the ILP. The ILP (CPU B 514 ) may again move the memory-resident copy of SINIT-AC 556 into secure memory 560 , along with a copy of a public key 564 . Upon verification and registration of SINIT-AC 556 , ILP may then continue to verification and registration of the memory-resident copy of SVMM 572 .
[0047] Referring now to FIG. 6 , a time line drawing of various operations is shown, according to one embodiment of the present invention. The timeline of FIG. 6 shows the overall schedule of the operations discussed in connection with the exemplary system discussed in connection with FIG. 2 above. When software decides that secure or trusted operations are desired, at time 610 any software locates and makes a copy of SINIT-AC 280 and SVMM 282 available to a subsequent SENTER instruction. In this example, software loads a copy of SINIT-AC 280 and a copy of SVMM 282 into one or more memory pages 250 - 262 . One processor, in the present example processor 202 , is then selected to be the ILP, which issues the SENTER instruction at time 612 . At time 614 the ILP's SENTER instruction issues the SENTER BUS MESSAGE 616 . The ILP then issues its own SENTER ACK 608 at time 618 prior to entering a wait-for-chipset-flag state at time 628 .
[0048] Each RLP, such as processor 222 , respond to the SENTER BUS MESSAGE 616 by completing the current instruction during time 620 . The RLP then issues its SENTER ACK 622 and then enters a state 634 where it waits for an SENTER CONTINUE MESSAGE.
[0049] The chipset 240 spends time 624 setting the JOINS register 272 responsive to the SENTER ACK messages observed on system bus 230 . When the JOINS register 272 contents matches the EXISTS register 270 contents, chipset 240 sets the ALL_JOINED flag 246 at time 626 .
[0050] During this time, the ILP may remain in a loop while polling the ALL_JOINED flag 246 . When the ALL_JOINED flag 246 is set, and ILP determines that the ALL_JOINED flag 246 is set at time 630 , the ILP may then issue the SENTER CONTINUE MESSAGE during time 632 . When the SENTER CONTINUE MESSAGE is broadcast on system bus 230 at time 636 , the RLPs may enter a wait-for-join state. For example, the RLP of processor 222 enters a wait-for-join state during time period 638 .
[0051] Upon issuing the SENTER CONTINUE MESSAGE, the ILP may then (in time period 640 ) bring the public key of key register 244 of chipset 240 and a copy of SINIT-AC into its secure memory 208 to form a copy of the key and a copy of SINIT-AC. In another embodiment, key register 244 may contain a digest of the public key, and the actual public key may be included in, or with, the SINIT-AC. Upon authenticating the copy of SINIT-AC as described above in connection with FIG. 2 , the ILP may then actually execute the copy of SINIT-AC within secure memory 208 .
[0052] After the copy of SINIT-AC within secure memory 208 begins execution, it then (during time period 640 ) validates and registers the memory-resident copy of SVMM. After the copy of SVMM is registered in the PCR 278 of security token 276 , the memory-resident copy of SVMM itself begins execution. At this time, during ongoing time period 650 , SVMM operations are established in the ILP.
[0053] Among the first things that the ILP SVMM operation does is issue individual RLP JOIN MESSAGES on the system bus 230 . An example is a processor 222 JOIN MESSAGE 644 . This message may include a location in memory at which the RLP processor 222 may join in execution of the registered memory-resident copy of SVMM. Alternatively, the ILP SVMM operations may have registered a memory location in a predetermined location in the chipset or memory, and upon receiving the JOIN MESSAGE the RLP retrieves its starting address from this location. After receiving the processor 222 JOIN MESSAGE, and determining its starting address, during time period 646 the RLP processor 222 jumps to this location and joins execution of the registered memory-resident copy of the SVMM.
[0054] After all the RLPs have joined the registered memory-resident copy of the SVMM, secured operations are established throughout the microcomputer system 200 .
[0055] Referring now to FIG. 7 , a flowchart of software and other process blocks is shown, according to one embodiment of the present invention. For the sake of clarity FIG. 7 only shows process blocks for a single representative RLP. In other embodiments there may be several responding logical processors.
[0056] The process 700 begins at block 710 when a logical processor makes a copy of the SINIT-AC and SVMM modules available for access by a subsequent SENTER instruction. In this example, in block 712 the ILP loads the SINIT-AC and SVMM code from mass storage into physical memory. In alternative embodiments, any logical processor may do so, not just the ILP. A processor becomes the ILP by executing the SENTER instruction, as identified in block 714 . In block 716 , the ILP SENTER instruction issues an SENTER BUS MESSAGE in block 716 . The ILP then, in block 718 , issues its own SENTER ACK message to the chipset. The ILP then enters a wait state, shown as decision block 720 , and waits for the chipset to set its ALL_JOINED flag.
[0057] After each RLP receives the SENTER BUS MESSAGE in block 770 , it halts execution with the end of the current instruction, and then in block 772 issues its own SENTER ACK. Each RLP then enters a wait state, shown as decision block 774 , and waits for a SENTER CONTINUE MESSAGE to arrive from the ILP.
[0058] The chipset sets the corresponding bits in the JOINS register when SENTER ACK messages are received. When the JOINS register contents equals the EXISTS register contents, the chipset sets its ALL_JOINED flag, signaling the ILP to proceed from decision block 720 .
[0059] The ILP, upon exiting decision block 720 on the YES path, then issues a SENTER CONTINUE MESSAGE in block 722 . This signals each RLP to proceed from decision block 774 . Each RLP then enters a second wait state, shown as decision block 776 , and waits for a SENTER JOIN MESSAGE.
[0060] Meanwhile the ILP, in block 724 , moves the public key of the chip set and the memory-resident copy of SINIT-AC into its own secure memory for secure execution. The ILP, in block 726 , uses the key to validate the secure-memory-resident copy of SINIT-AC, and then executes it. The execution of SINIT-AC may perform tests of the system configuration and the SVMM copy, then registers the SVMM identity, and finally begins the execution of SVMM in block 728 . As part of actions performed in block 728 , the ILP SINIT code may configure device-access page table 248 and device-access logic 247 of memory and chipset to protect those memory pages used by the memory-resident copy of SVMM 282 from interference by non-processor devices, as shown in block 754 .
[0061] After the ILP begins execution under the control of SVMM, in block 730 the ILP sends an individual SENTER JOIN MESSAGE to each RLP. After issuing the SENTER JOIN MESSAGE, the ILP then in block 732 begins SVMM operations.
[0062] The receipt of the SENTER JOIN MESSAGE causes each RLP to leave the wait state represented by decision block 776 along the YES path, and begin SVMM operations in block 780 . The SENTER JOIN MESSAGE may contain the SVMM entry point the RLP branch to when joining SVMM operations. Alternatively, the ILP SVMM code may register the appropriate RLP entry point in a system location (for example, in the chipset), to be retrieved by the RLP upon receipt of the SENTER JOIN MESSAGE.
[0063] While various embodiments disclosed include two or more processors (either logical or physical processors), it should be understood that such multi-processor and/or multi-threaded systems are described in more detail to explain the added complexity associated with securing a system with multiple logical or physical processors. An embodiment also likely to be advantageous in less complex system may use only one processor. In some cases, the one physical processor may be multi-threading and therefore may include multiple logical processors (and accordingly have an ILP and an RLP as described). In other cases, however, a single-processor, single-threaded system may be used, and still utilize disclosed secure processing techniques. In such cases, there may be no RLP; however, the secure processing techniques still operate to reduce the likelihood that data can be stolen or manipulated in an unauthorized manner.
[0064] In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
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A method and apparatus for initiating secure operations in a microprocessor system is described. In one embodiment, one initiating logical processor initiates the process by halting the execution of the other logical processors, and then loading initialization and secure virtual machine monitor software into memory. The initiating processor then loads the initialization software into secure memory for authentication and execution. The initialization software then authenticates and registers the secure virtual machine monitor software prior to secure system operations.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority to Italian patent application FI2010A000173 filed on Aug. 5, 2010, which is incorporated herein by reference in its entirety.
FIELD
The present disclosure is related to ophthalmic devices and methods, and in particular devices and methods for analysing the cornea and/or the anterior segment of the eye.
BACKGROUND
Over the last few years a series of ophthalmic devices of the aforementioned type have been developed, based upon a slit illumination of a section of the cornea and upon the recording of such an illuminated section through a suitable observation system. Most of such devices capture and record images of various sections of the eye, through rotation of the capturing devices around the optical axis of the eye and, through suitable processing, they obtain a three-dimensional reconstruction of the anterior chamber of the same eye.
One of the main problems that has been experienced when using this kind of devices is that the eyes of the patient, however cooperative and concentrated he may be on correctly fixing the fixation point provided by the device, cannot keep absolutely still. On the other hand the scanning of the eye requires a certain period of time in order to be completed. Therefore, what occurs is that during the rotating scanning, the ideal position for capturing the eye becomes misaligned with respect to the rotation axis of the capturing device. This misalignment, when positioning the single sections with respect to one another and therefore in the three-dimensional reconstruction phase of the anterior chamber, can lead to artefacts and considerable errors.
In order to solve this problem, different “a posteriori” correction methods have been proposed and implemented in devices that are currently on the market. An example of such a way to approach the problem is provided by the device described in EP1430829. Indeed, a specific functional solution forms the object of such a patent, that is, simultaneously recording sectional images and front images, the latter showing an image of the illuminated sectional portion of the cornea, so as to make it possible to assign a section captured at a time T to the area that is indeed illuminated, formed by the front image.
This second solution has the following drawbacks:
saving the image twice (from the front and from the side) means an extra functional workload of the examination and an increase in the computational costs; compensation a posteriori, in any case, does not offer a completely satisfactory solution, since it is necessary for there to be a mathematical interpolation of the data when assigning them to their position again, and an interpolation is of course less reliable than a direct data measurement.
Active correction solutions are also known. For example, U.S. Pat. No. 7,712,899 describes a solution with two perpendicular channels for simultaneously recording two sections of the eye and a third video observation channel, that is capable of detecting the possible misalignment of the eye and the consequent correction through the movement of a considerable part of the two recording systems of the sections.
A system of this kind however, in turn, is structurally and operatively complex, and therefore its practical application comes up against constructive problems, control difficulties and inaccuracy of the results.
SUMMARY
According to an aspect of the present disclosure, a method and a measuring device are provided, that solve the problem of misalignment of the eye of the patient during the examination in a more satisfactory manner, in terms of simplification and reduction of the examination costs and of accuracy of the results, with respect to known systems that follow an a posteriori approach, like the one mentioned above for instance, or others that, again within such a generic approach, adopt alternative solutions.
According to a further aspect of the present disclosure, a method and a device of the aforementioned type are provided, which adopt an active or pre-emptive correction system that is reliable, constructively and functionally simple.
According to another aspect, an ophthalmologic device for capturing and/or measuring features of an anterior chamber of an eye of a patient is provided, the device comprising: a first light projection system adapted to illuminate a cross-section of the anterior chamber under examination with an illumination light beam along a relevant optical axis; a capturing system adapted to observe an image of the cross-section of the anterior chamber illuminated by said first light projection system in a correct capturing position; a second light projection system adapted to generate a fixation light beam determining a fixation point for the eye of the patient as a reference for said correct capturing position; and detection and control means comprising: a mobile optical member adapted to interfere at least with said illumination beam and, with its motion, to displace the beam; sensor means adapted to detect a movement of the eye with respect to said correct positioning; and a control unit adapted to control, as a response to the detection by said sensor means, the operation of said mobile optical member to displace said beam towards said correct capturing position.
According to still another aspect, a method for capturing images and/or measuring features of an anterior chamber of an eye of a patient is provided, comprising: illuminating a cross-section of the anterior chamber under examination with an illumination light beam of a first light projection system along a relevant optical axis; observing with a capturing system an image of the cross-section of the anterior chamber illuminated by said illumination light beam in a correct capturing position; and generating with a second light projection system a fixation beam determining a fixation point for the eye of the patient as a reference for said correct capturing position, wherein a mobile optical member interferes at least with said illumination beam, a movement of the eye with respect to said correct position is detected, and in response to the detection the operation of said mobile optical member is controlled to displace said beam towards a correct capturing position.
A first light projection system creates a flat blade of light, which passes through a cross-section of the anterior chamber of the eye under examination. This light is diffused by the eye structures it meets, and can be observed by a capturing or acquisition system arranged at a certain angle with respect to the plane of the blade of light. The capturing system forms a focused image on the sensor that records the section of the anterior chamber crossed by the blade of light.
The patient is required to fix a fixation point, consisting of a collimated beam generated by a second illumination and projection system. The aforementioned blade of light of the first light projection system is parallel to the fixation beam.
The movements of the eye are detected through reading the image of the collimated fixing beam reflected by the cornea, by an electro-optical detection element.
A mobile optical member, inserted in the common path of the blade of light of the first light projection system, of the collimated beam of the second light projection system and of the reflected image of the cornea, allows for a controlled translation of the same blade, and of the other beams, in a direction that is perpendicular to the lying plane of the same beam.
The possible movements of the eye of the patient, with respect to the device, lead to its displacement away from the ideal position, said position being that in which the blade of light passes through the corneal vertex. The measurement system quantitatively defines the amount of such a movement. In response to this measurement the mobile optical member, crossed by the beams, is moved of an amount suitable in order to displace the blade of light to the position passing through the corneal vertex. In these conditions, also the reflected image of the cornea is re-aligned on the corneal vertex.
According to embodiments of the present disclosure, the misalignment of the eye of the patient is actively corrected by bringing the blade of light back to the corneal vertex, in the case in which, when capturing a frame, the position of the patient is not correct.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics of the ophthalmic device and method according to the present disclosure shall become clearer from the following description of one of its embodiments, given as an example and not for limiting purposes, with reference to the attached drawings, in which:
FIGS. 1 a and 1 b represent an example diagram of the device for analysing the anterior segment of the eye in which, in FIG. 1 a , the optical path of the illumination is marked from the source to the eye and, in FIG. 1 b , the optical path of the fixation point from the source to the eye and of the reverse path of the image reflected by the cornea are marked;
FIGS. 2 a , 3 a , 2 b , 3 b , 2 c and 3 c represent pairs of views of the eye under examination, each pair including a front view and a section view, respectively in three different situations of (mis)alignment of the eye and of translation of the blade of light for illuminating the same eye.
DETAILED DESCRIPTION
With reference to FIGS. 1 a and 1 b , in an embodiment of the device according to the present disclosure an illuminator 11 frontally illuminates, in a first light projection system wholly indicated with reference numeral 1 and that can be defined as central, an eye E of a patient, and in particular the relative anterior chamber so as to highlight a section thereof.
The central optical system comprises an optical group 12 such as to make the light emission of the illuminator 11 —at the correct capturing distance that can be determined according to known optic principles—a blade of light L ( FIG. 1 a ).
A capturing system 2 is arranged outside the central projection beam in a way such as to focus, on an image capturing device 21 thereof, typically a CCD sensor, the section illuminated by the central optical system 1 , and in particular by the illuminator 11 . The sensor 21 observes the section of the cornea from a position outside the blade of light generated by the illuminator 11 and can be arranged, for example, according to a Scheimpflug configuration.
A light source 311 generates a luminous fixing point and projects it towards the eye E through a second light projection system to obtain a collimated light beam F, in a way such as to be perceived to infinity by the patient. Such a system, wholly indicated with reference numeral 3 , comprises a diaphragm 312 , a group of lenses 313 , all integrated with the source 311 in a fixing device 31 which—as such—can be considered as conventional. The fixing device 31 is arranged so as to obtain a projection that is parallel to the projection of the first system 1 .
The second light projection system 3 further comprises a pair of beam deviators or beam splitters 32 , 33 , the first of which, indicated with reference numeral 32 , deviates the projection of the fixing device onto an optical axis of the second light projection system, sideways or, like in the example, perpendicular to the first optical axis. The second beam splitter 33 is arranged on the optical axis of the first system, so as to deviate the projection of the fixing device 31 along such first optical axis, downstream of the previously mentioned optical element 12 , and cooperates with other optical elements 34 , arranged further downstream, i.e. towards the eye E, suitable for achieving the desired collimation ( FIG. 1 b ).
As a constructional fixed parameter, the blade of light generated by the illuminator 11 of the first central system lies on a plane that is parallel to the direction of the collimated fixing beam generated by the fixing device 31 . Consequently, when the eye E is positioned correctly for the imaging capture on the plane xy (i.e. plane tangent to the eye at the point of incidence of the central optical axis, see the reference Cartesian coordinate system indicated in FIG. 1 a ), the image point of such a fixation beam, reflected by the cornea, lies on the plane of the blade of light.
A detector 4 , typically in the form of a matrix of electro-optical sensors 4 , is associated with the second light projection system, along the relative lateral optical axis, so as to be adapted to detect the position of an image, reflected by the cornea, of the collimated fixing beam, generated as mentioned by the fixing device 31 , and therefore in turn deviated by the above described components. The reflected beam is represented with a lighter line, with respect to that of the collimated beam, in FIG. 1 b.
A processing and control unit 5 comprises processing means suitable for receiving and processing the digital signal detected by the detector 4 , i.e. a signal representative of the position of the reflected image of the collimated beam on the cornea of the eye E. A man skilled in the art will appreciate that such a result can be obtained both by a digital-based processing and by analogue control means. The processing unit 5 is also suitable for emitting a control signal of an actuator 6 , the actuation of which drives a mobile optical member 7 arranged so as to intersect the blade of light, the collimated fixation beam and the corresponding collimated image of the cornea, so as to be able to displace the blade of light and to keep it centred in the position of the corneal vertex, actively compensating for voluntary or involuntary movements of the eye of the patient.
In a possible embodiment such a mobile optical member 7 , placed between the first and second light projection system 1 , 3 and the eye E, can be made up of a simple parallel flat transparent lamina pivoting (as indicated by the arrows) around an axis that is parallel with the plane xy and with the lying plane of the blade of light L. Therefore, in practice, this rotation axis is in accordance with the direction defined by the axis indicated with y in FIG. 1 a . The lamina, when its faces are perpendicular to the blade of light (nominal position), does not alter the optical path thereof. On the other hand, by tilting the lamina 7 with respect to the nominal position, the blade of light that illuminates the eye is translated by an amount depending on the tilt angle (again see the arrows of FIG. 1 a ). It should moreover be noted that such a tilting of the lamina 7 does not modify the direction of the collimated fixation beam projected by the fixing device 31 , which is thus perceived always in the same direction by the patient. From the point of view of the sensor 4 , on the other hand, the movement of the blade of light caused by the tilting of the lamina 7 is perceived (reflection F′ in FIG. 1 b ) as an opposite movement of the image of the reflection of the collimated fixation beam. When such a reflection lies on the plane of the blade of light, its image on the sensor 4 is in a position that is univocally determined and represents the position of correct alignment.
The processing and control unit 5 , based upon the error detected by the sensor 4 , thus drives the tilting of the lamina 7 so that such an error is made null, obtaining, in such a way, the aforementioned alignment. In practice, the error is made null when, thanks to the prismatic effect of the lamina 7 , the reflection of the fixation point F′ has returned to the centre of the sensor 4 and with it the blade of light L has returned to strike the cornea at its vertex. Such a control procedure can of course be run with a software that is obviously implemented on the unit 5 .
In order to better and further understand how the device according to the present disclosure works, reference will now be made to the situations shown in FIGS. 2 and 3 ( a, b, c ).
In FIGS. 2 a and 3 a the ideal situation is shown in which the eye is aligned, the reflection of the fixation point is aligned with the corneal vertex, the plane of the blade of light passes through the corneal vertex. In this case the processing and control unit 5 can keep the lamina 7 in the nominal condition.
In FIGS. 2 b and 3 b a non-ideal situation is shown in which the eye is not aligned properly, the reflection of the fixation point is displaced from the corneal vertex by a certain amount, and the plane of the blade of light does not pass through the corneal vertex if the lamina 7 is kept in the nominal position. Such a situation is detected thanks to the sensor 4 and acquired by the unit 5 . In response, to displace the blade of light, so that it goes back to the corneal vertex, it is necessary for the unit 5 to tilt the lamina 7 by a certain angle. In FIGS. 2 c and 3 c the situation in which this occurs is shown. At this stage, the illuminated ocular section is the desired one, that is, the section passing through the corneal vertex, even if the eye is misaligned (misalignment that can be noted from the displacement with respect to the origin of the Cartesian system represented in the figure sand taken as a reference).
The present disclosure has been described thus far with reference to its possible example embodiments. It should be understood that other embodiments can is make use of optical configurations that, though arranged differently from those here shown and integrated with additional components/functions, are within the scope of protection of the following claims.
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An ophthalmic device and method actively correcting possible movement of the eye of a patient with respect to the correct positioning during the examination are described. An illumination light beam is provided, that passes through a cross-section of the anterior chamber of the eye to capture an image on the corneal vertex.
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BACKGROUND OF THE INVENTION
This invention relates to frequency adjusting methods and systems for adjusting the frequency of an electrical signal to approximate to a desired frequency.
Synthesis of a desired frequency can be carried out using a phase-locked loop to generate an output frequency which is a whole multiple of a base frequency fed to the phase comparator of the loop, the multiplication factor being introduced by an integer division operation applied to the output frequency feedback. A change in output frequency to approximate that frequency to a desired value is effected by changing the multiplication factor of the loop. Clearly the output frequency can only be adjusted in steps equal to the base frequency. Since it is undesirable to have a very low base frequency or a very high multiplication factor, frequency synthesis so effected either has large steps in output frequency or is restricted to low frequency bands.
An object of the invention is to provide improved frequency adjusting or synthesising methods and systems.
BRIEF SUMMARY OF THE INVENTION
According to the invention, there is provided an electrical frequency adjusting system, comprising first and second interconnected frequency changing circuits arranged to serially process an input frequency to produce an output frequency differing therefrom, one said circuit serving to effect frequency division by an integer division factor, the other said circuit serving to effect frequency multiplication by an integer multiplication factor differing from said division factor by an offset integer, and factor-adjusting means for adjusting the division and multiplication factors by the same absolute integer value to enable adjustment of the output frequency over a range of frequencies.
According to the invention, there is also provided a method of adjusting an output frequency to approximate to a desired frequency, the method comprising the steps of changing an input frequency to an intermediate frequency, changing the intermediate frequency to an output frequency approximating to the said desired frequency, one said frequency changing step being a frequency division by an integer division factor and the other frequency changing step being a frequency multiplication by an integer multiplication factor differing from the division factor by an offset integer, and adjusting the division and multiplication factors within predetermined limits to values such that the ratio of the offset integer to the division factor is the closest available approximation within those limits to the difference between the input and desired frequencies expressed as a proportion of the input frequency.
DESCRIPTION OF THE DRAWINGS
Frequency adjusting methods and systems, each according to the invention, will now be particularly described by way of example only, with reference to the accompanying diagrammatic drawings, in which:
FIG. 1 is a block circuit diagram of one of the systems;
FIG. 2 is a block diagram representing the system of FIG. 1 in simplified form;
FIG. 3 is a block circuit diagram of another of the systems;
FIG. 4 is a block circuit diagram of a frequency adjusting system comprising two cascaded systems of the FIG. 1 form;
and
FIG. 5 is a block circuit diagram of a frequency synthesiser.
DESCRIPTION OF PREFERRED EMBODIMENTS
The frequency adjusting system shown in FIG. 1 comprises a frequency divider 11 which divides an input frequency F by an integer division factor N. The resulting intermediate frequency F/N is then multiplied up by an integer multiplication factor (N-b) using a frequency multiplier 12 (indicated by dashed lines in FIG. 1) formed by a phase-locked loop comprising a voltage-controlled oscillator 13, a frequency divider 14 (with a division factor of (N-b), a phase comparator 15, and a low pass filter 16. The output Fo of the multiplier 12 is the frequency F/N multiplied by (N-b), that is, Fo=F(1-b/N) which is generated at the output of the voltage-controlled oscillator 13. The frequency Fo is the system output frequency. The divider 11 and the multiplier 12 can be considered as two frequency changing circuits which serially process an input frequency F to give an output frequency Fo=F(1-b/N), and can therefore be represented as shown in FIG. 2.
FIG. 3 shows a modified form of the system of FIG. 1 in which parts corresponding to parts in FIG. 1 are similarly referenced.
In FIG. 3, the frequency F/N is again fed into one input of the phase comparator 15. The second input of the comparator 15 receives the output frequency of a frequency divider 17 which has a division factor b, thus differing from the frequency divider 14 of FIG. 1 which has a division factor of (N-b). The input of the divider 17 is fed from the output of a mixer 18 which receives the first input from the VCO 13 and a second input carrying the input frequency F.
A filter (not shown) selects the difference frequency output (F-F o ) from the mixer 18 for application to the divider 17.
In the phase-locked loop of FIG. 3, therefore, ##EQU1## Therefore, the arrangement of FIG. 3 operationally corresponds to the arrangement of FIG. 1 and can again be represented by the block diagram of FIG. 2.
Referring to FIG. 2, the value of the integer b, which may be termed an offset integer, can be either positive or negative, constant or variable, (in the case of the FIG. 3 arrangement b is positive when F o is greater than F so that the mixer output fed to the divider 17 is F o -F).
Initially considering b to be kept constant, then as the value of the integer N is varied by the same absolute value in both the division factor of the divider 11 and the multiplication factor of the multiplier 12, the output frequency of the system varies in steps S of a magnitude which may be calculated by considering the successive values of the output frequency, (that is, for N=N' and N'+1) ##EQU2##
It can be seen that the step changes in output frequency are b/N times the frequency F/N fed to multiplier 12. This is in contrast to one known form of frequency synthesiser which simply multiplies up a base frequency F by an integer factor giving output frequency steps of F. Thus for the same output frequency step size, the frequency fed to the multiplier is N/b larger in the FIG. 2 system which is of advantage. Considering a specific example, for an output frequency of around 1 MHz alterable in 1 Hz step sizes, the previous synthesiser would require a base frequency of 1 Hz and a value of N of 10 6 . The FIG. 2 system can use a multiplier input frequency of 1 kHz and values of N of 10 3 with b equal to unity.
For a given value of b, the FIG. 2 system has a stepped output frequency range the span of which is determined by the maximum and minimum values of N. Since the frequency step size S is approximately Fb/N 2 , the size of step will decrease (and the output frequency increase) as N is increased.
By changing the value of b to a different integer, another stepped frequency range can be obtained by varying the value of N. Making b settable to a number of different values enables a corresponding number of stepped frequency ranges to be obtained. These ranges may overlap with each other depending on the range of values of N available.
Not only will the frequency step size S vary within each stepped frequency range as N changes, but the higher frequency ranges (that is, with lower values of b) will generally have smaller step sizes.
The maximum and minimum values of N and b to give a desired overall output frequency span ΔF without interruptions between successive stepped frequency ranges can be readily derived as set out below.
(1) The overall output frequency span ΔF is given by ##EQU3##
(2) For the lowermost output frequency, use N=N min , b=b max. As the output frequency is required to increase, increase N keeping b constant until a value of N is reached satisfying ##EQU4## At this point, change b to b max -1 and start again from N=N min . When a value of N is then reached satisfying ##EQU5## change b to b max -2 and put N back to N min . Continue in this way until the full range of output frequencies has been generated. The value of N max is then given by ##EQU6##
To provide an output frequency approximating to any particular desired frequency in the overall output frequency span of the system, the appropriate value of b and N are calculated to select the stepped frequency range required and the nearest spot frequency in that range to the desired frequency. The division factors of the dividers 11 and 14 are then set to N and (N-b) respectively. The selection of the values of the factors N and (N-b) may be performed in any suitable manner, for example using a microprocessor or a look-up table held in memory and arranged to output factor values appropriate for the desired frequency.
The error between the desired and actual output frequency of the synthesiser is at most equal to half the frequency step size S, thus:
ε≦1/2S
The maximum error will occur when S is greatest, that is, when b is a maximum and N a minimum: ##EQU7##
From an alternative viewpoint, selection of the required value of b and N to give an output frequency approximating to a desired frequency may be considered as a selection of the multiplication and division factors (within the possible ranges of these factors as set by the system design) such that the ratio of the offset b to the division factor N is the closest available approximation to the difference between the input and desired frequencies expressed as a proportion of the input frequency. Thus if F d is the desired frequency ##EQU8## (The above equation may be derived by setting the output frequency formula given in FIG. 1 to approximately equal F d ).
In cases where the range of output frequencies is sufficiently small, the voltage controlled oscillator in the multiplying circuit could advantageously be crystal controlled, thereby giving a spectrally very pure output frequency.
Two or more frequency adjusting systems of the FIG. 2 form can be cascaded to give a wider overall frequency span (FIG. 4 system) or finer frequency steps.
In the FIG. 4 system, two frequency adjusting systems 20 and 21 (indicated by dashed lines) are used, each having the form shown in FIG. 1 (but alternatively each could have the form shown in FIG. 3). The systems 20 and 21 respectively act as fine and coarse frequency adjusting means. The system 20 has integer division and multiplication factors of N and (N-b) respectively and generates an output frequency F (1-b/N) from an input frequency of F. The system 21 has integer division and multiplication factors M and (M-c) and processes the output frequency of the system 20 to produce a final output frequency of F (1-b/N) (1-c/M).
The second, "coarse", frequency adjusting system is arranged to have a large step change in output frequency and a wide overall span of output frequencies. The first, "fine", frequency adjusting system 20 is used to provide intermediate frequency steps. Thus, for example, the "coarse" system could have c=1, M=50 to 100 giving a possible 1% change in output frequency with a maximum step size of approximately 4.10 -2 %. If the "fine" system 20 has b=1, N=1000 to 2000, its range of output frequency adjustment is 5×10 -2 %. which is sufficient to cover the largest step change due to the "coarse" system. The largest step change due to the "fine" system 20 is 1 part in 10 6 . Thus the overall system of FIG. 4 produces step changes of 1 ppm over a range of 1% of output frequency.
To give very fine step changes in frequency the FIG. 4 system can be modified by setting M equal to N and c equal to (-b). The overall system output frequency is thus: ##EQU9##
The step change in output frequency for a change in the value of N for both circuits 20 and 21 is:
2b/N.sup.3
For example, for N=10 3 , b=1, a fractional change in output frequency of the order of 2 parts in 10 9 is possible.
The frequency adjusting system of FIG. 2 can be used to compensate for an error in a frequency standard due, for example, to temperature provided the a parameter such as temperature dependency of the error from a nominal frequency is known. Thus if a frequency standard unit which comprises a frequency source is arranged to generate a source frequency F (1+x) where x is the undesired parameter error to be compensated for, than after processing by the FIG. 2 system an output frequency is produced of F (1+x) (1-b/N). This output frequency can be kept constant by choosing N and b to give: ##EQU10##
It will be seen from this equation for b/N and from FIG. 2, that minimizing the error x in the output frequency may be achieved in such a system by including means connecting the adjusting means for the factors b and N to be responsive to the parameter, such that the division and multiplication factors are adjusted by the same absolute integer value and in dependence on the parameter.
The described frequency adjusting systems can be advantageously used in frequency synthesisers having a wide range of output frequencies, as shown in FIG. 5. In the synthesiser shown in this Figure, a frequency adjusting system 30 precedes a divider 31 dividing by a factor K and multiplier circuit 32 multiplying by a factor m, either of which can be variable. Varying the value of the factor m causes large steps in output frequency while the frequency adjusting system 30 can be used to give intermediate steps. Since the output of the frequency adjusting system 30 has only small changes in output frequency, the voltage controlled oscillator 33 of the system 30 could advantageously be crystal controlled, giving a spectrally very pure reference frequency to the multiplier circuit 32. For example, if the output frequency required is 30 to 60 MHz in 10 Hz steps accurate to 2 Hz, the input frequency to the multiplier circuit 32 could be made approximately 10 kHz. The multiplication factor m would then in the range 3000 to 6000. The frequency adjusting system 30 would be required to have a range of 333 ppm, and suitable ranges of N and b would be 10000 to 15000 and 5 to 2 respectively. These values would give a maximum output step size of 0.05 ppm or 3 Hz at 60 MHz; the maximum frequency error would then be 1.5 Hz.
An advantage of varying K and keeping m constant, instead, is that the loop 32 then has a constant gain.
In FIG. 5, the frequency adjusting system 30 is shown as being a system of the form shown in FIG. 1. Instead, of course, it could be a system of the form shown in FIG. 3.
In the systems described above the reference to FIGS. 1, 2 and 3, the step of frequency division has been illustrated as being carried out before the step of frequency multiplication. However, it will be appreciated that the order of these steps can be reversed so as to carry out frequency multiplication before frequency division.
The system shown in FIG. 3 may be advantageous as compared with the system of FIG. 1 in certain circumstances because the system of FIG. 3 involves only a single variable divider (divider 11) which illustrates one means for simultaneously adjusting the frequency division and multiplication factors.
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A frequency synthesizing arrangement is disclosed employing a phase-locked loop. The phase detector of the phase-locked loop receives an input frequency via a divider having a division factor N, and compares this divided frequency with the frequency received from a voltage controlled oscillator via a divider having a division factor N-b. Any difference is eliminated by the control signal from the phase detector which is connected to adjust the VCO frequency. Therefore, the phase-locked loop multiplies the divided input frequency by the factor (N-b). By making b very much smaller than N, the minimum step change in output frequency is approximately F.b/N 2 (where F is the input frequency to the divider). In this way, the minimum step change in frequency can be made very small.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a linear compressor for compressing refrigerant by using a reciprocating piston. More particularly, the present invention relates to a piston operating assembly for the linear compressor and a method for manufacturing the same.
[0003] 2. Description of the Prior Art
[0004] Generally, a linear compressor compresses a refrigerant by reciprocating a piston with a changing magnetic field. Such a compressor is shown in FIGS. 1 through 3.
[0005] As shown in the drawings, the linear compressor includes a cylinder portion 10 , a piston 20 , a piston operating assembly 30 and an external lamination portion 40 , all of which are disposed in a chamber 1 .
[0006] As shown in FIG. 2, the piston operating assembly 30 includes a magnet holder 32 , which is a hollow cylinder having a hole formed in an outer circumference thereof, a magnet 33 inserted in the hole of the magnet holder 32 , a magnet cover 35 press fit on the outer circumference of the magnet holder 32 to prevent any accidental separation of the magnet 33 from the magnet holder 32 , and a linking member 31 having a hole formed on the center portion thereof for receiving the piston 20 . The linking member 31 is connected to one end of the magnet holder 32 .
[0007] The piston 20 is a hollow cylinder, having one end attached to a suction valve 25 and the other end coupled to the linking member 31 of the piston operating assembly 30 . The piston 20 can be secured to the linking member 31 by one of a number of methods, such as welding, etc.
[0008] The cylinder portion 10 includes a cylinder 11 , in which the piston 20 is received for reciprocating movement, an internal lamination 13 inserted about the outer circumference of the cylinder 11 , and a coil 15 wound about the center portion of the internal lamination 13 .
[0009] An external lamination portion 40 includes an external lamination 41 formed a predetermined distance from the internal lamination 13 , a housing 43 for supporting the external lamination 41 , and a frame 42 .
[0010] The operation of the linear compressor constructed as above will be described below.
[0011] First, when Alternating Current (AC) voltage is applied to the coil 15 of the internal lamination 13 , a magnetic field having N-S poles is generated between the internal and external laminations 13 and 41 , respectively. Due to the presence of the permanent magnet 33 disposed between the internal and external laminations 13 and 41 , a force in an axial direction is generated according to Flemming's left-hand rule. As the N-S poles of the magnet 33 are varied, the magnet 33 reciprocates, and accordingly, the piston 20 also reciprocates.
[0012] Next, a refrigerant is introduced into the chamber 1 through an inlet tube 3 by the reciprocating movement of the piston 20 . The refrigerant flows through the piston 20 and the suction valve 25 and into a compressing chamber 5 . When the refrigerant is compressed in the compressing chamber 5 , the refrigerant is then discharged through an outlet tube 7 .
[0013] The conventional linear compressor, however, has several shortcomings. First, some parts of the compressor require forceful coupling methods, such as force fit, welding, etc., to secure the parts together. For example, the piston 20 and linking member 31 are welded together, as are the linking member 31 and the magnet holder 32 . Further, the magnet holder 32 must undergo processes like cutting, punching and welding. The force of the couplings and heat distortion of the respective parts produce an internal stress that affects the integrity of the parts. Further, the conventional linear compressor has a complex and lengthy assembly process, while producing a high possibility of defective products. As a result, productivity and throughput are deteriorated.
[0014] The manufacturing process of the magnet holder 32 is described in greater detail with reference to FIG. 3. First, a metal plate 32 a of a predetermined size is prepared. Then, the metal plate 32 a undergoes a rolling process. Next, the ends of the metal plate 32 a are welded together to form a hollow cylinder 32 b . The hollow cylinder 32 b is then punched to form a plurality of holes 32 c therein. Finally, in order to prevent any accidental separation of the magnets 33 from the hollow cylinder 32 b , a magnet cover 35 is force fit onto the outer circumference of the hollow cylinder 32 b.
[0015] In the conventional linear compressor, the different sizes of and deviations among the magnets 33 make it difficult to press fit or force fit the magnet cover 35 . When the magnet cover 35 is forcefully press fit, without taking into consideration the different sizes of the magnets 33 , those magnets 33 that are more fragile can be broken.
[0016] Further, according to a conventional way of assembling the piston operating assembly 30 of the linear compressor, an error in concentricity occurs when the piston 20 and the magnet holder 32 are welded to the linking member 31 , and errors in circularity and concentricity occur when press fitting the magnet 33 , which is press fit in the magnet holder 32 , in the magnet cover 35 . Accordingly, productivity and throughput deteriorate. Further, since there are numerous parts that must be assembled together, all of which affect the geometric tolerance of the piston operating assembly 30 , the assembly tolerance is increased due to an accumulation of the tolerances of the respective parts. When the geometric tolerance and the assembly tolerance exceed a predetermined degree, the same becomes a defect factor, which can cause problems, such as a malfunction of the linear compressor, etc.
[0017] In addition, in the conventional method of assembling the linear compressor, a non-magnetic metal is used to form the magnet holder 32 , thereby preventing a leakage of the magnetic force from the magnet 33 . The non-magnetic metal of the conventional linear compressor, however, has a relatively higher conductivity, which hinders a complete absence of the magnetic force leakage from the magnet 33 . Accordingly, due to the leakage of the magnetic force from the magnet 33 , the compression efficiency of the linear compressor is negatively affected.
SUMMARY OF THE INVENTION
[0018] The present invention has been made to overcome the above-mentioned problems of the prior art. Accordingly, it is an object of the present invention to provide a piston operating assembly for a linear compressor having a piston coupling boss coupled with a piston, a plurality of magnets, and a linking member. The linking member connects the piston coupling boss with the magnets, all of which are integrally secured to the linking member when the linking member is injection molded. Thus, the integrated piston operating assembly has improved geometric and assembling tolerances and no deterioration of persistence.
[0019] It is another object of the present invention to provide a method for manufacturing a piston operating assembly for a linear compressor. In the present method the processes are simplified while resulting in a higher productivity.
[0020] The above object is accomplished by a piston operating assembly of a linear compressor for compressing a refrigerant with a piston that linearly reciprocates due to a magnetic field. The piston operating assembly includes a piston coupling boss for coupling to the piston, a plurality of magnets disposed in a cylindrical arrangement concentric with respect to the piston coupling boss, and a linking member for connecting and thus integrating the piston coupling boss and the plurality of magnets. The linking member is formed of an injection molded resin, and the piston coupling boss and the magnets are coupled to the linking member at the same time that the linking member is injection molded.
[0021] Each of the magnets has a stepped portion that is formed along a boundary thereof.
[0022] The above object is also accomplished by a method for manufacturing a piston operating assembly for a linear compressor. The method includes the steps of preparing a plurality of magnets and a piston coupling boss, assembling the plurality of magnets and the piston coupling boss in a core mold, and mounting the core mold in an injection molding machine. The method further includes injecting a molding resin into the core mold to form an integrated piston operating assembly, with the plurality of magnets and the piston coupling boss fixed in the molding resin. The completed integrated piston operating assembly is then separated from the core mold, once the injection molding is finished.
[0023] Accordingly, the piston operating assembly of the linear compressor has improved geometric and assembling tolerances and persistence. In addition, the method of manufacturing such piston operating assembly is greatly simplified and results in an increase in productivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above objects and other features and advantages of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:
[0025] [0025]FIG. 1 is a sectional view of a conventional linear compressor;
[0026] [0026]FIG. 2 is a sectional view of a piston operating assembly for the conventional linear compressor of FIG. 1;
[0027] [0027]FIG. 3 illustrates the steps for manufacturing a conventional magnet holder for the conventional linear compressor of FIG. 1;
[0028] [0028]FIG. 4 is a plan view of a plurality of magnets, which are employed in a piston operating assembly for a linear compressor, in accordance with the present invention;
[0029] [0029]FIG. 5 is a sectional view of a piston coupling boss, which is employed in the piston operating assembly for the linear compressor, in accordance with the present invention;
[0030] [0030]FIG. 6 is a perspective view of the piston operating assembly for the linear compressor, in accordance with the present invention;
[0031] [0031]FIG. 7A is a plan view of a core mold, which is used to manufacture the piston operating assembly of FIG. 6;
[0032] [0032]FIG. 7B is a cross-sectional view taken generally along the line I-I of FIG. 7A;
[0033] [0033]FIG. 8 is a sectional view of the core mold of FIGS. 7A and 7B shown mounted in an injection molding machine during manufacture of the piston operating assembly of FIG. 6; and
[0034] [0034]FIG. 9 is a flow chart illustrating the steps in a method for manufacturing the piston operating assembly of FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] The preferred embodiment of the present invention will be described below with reference to the accompanying drawings.
[0036] [0036]FIG. 6 is a perspective view of a piston operating assembly 50 for a linear compressor in accordance with the present invention.
[0037] The piston operating assembly 50 includes a plurality of magnets 51 disposed in a cylindrical arrangement and spaced from each other at equal intervals, a hollow piston coupling boss 52 concentrically disposed within the cylindrical arrangement, and a linking member 53 for connecting the cylindrical arrangement to an end of the piston coupling boss 52 . The magnets 51 , piston coupling boss 52 , and linking member 53 are preferably secured together simultaneously with the formation of the linking member 53 ..
[0038] In order to compress a refrigerant, a piston reciprocates in the cylinder of a linear compressor. The piston operating assembly, which moves the piston within the cylinder of the compressor, includes a piston coupling boss 52 that has a screw portion 52 b (FIG. 5). The screw portion 52 b includes threads that engage the threads formed at one end of the piston. The integrated piston operating assembly is preferably injection molded using a molding resin. As shown in FIG. 5, in order to increase the coupling force between the piston coupling boss 52 and the molding resin, a female screw portion 52 b is formed in one end of the piston coupling boss 52 , while a raised portion 52 a is formed at the opposite end. It is further preferable that the piston coupling boss 52 is made of a brass.
[0039] Because of the changes of magnetic field between the internal and external laminations 13 and 41 , the magnets 51 cause the piston to reciprocate. Each magnet 51 has a stepped portion formed around its boundary. As shown in FIG. 4, each magnet 51 is a square plate having a predetermined radius of curvature. The two opposite sides of the magnet 51 are processed to have an L-shaped cross-section, while the other two opposite sides of the magnet 51 are processed to have an upended L-shaped cross-section. By processing the sides of the magnet 51 to have L-shaped and upended L-shaped cross-sections, the coupling force between the piston operating assembly 50 and the molding resin is increased when the piston operating assembly 50 is integrally formed by injection molding.
[0040] The molding resin is preferably a non-magnetic and non-conductive thermosetting resin, such as a bulk molding compound composed of polyester as a main material, glass fiber as a reinforcing material, filler, and catalyst, etc.
[0041] In the piston operating assembly 50 for the linear compressor of the present invention, since the piston coupling boss 52 and the plurality of magnets 51 are integrally formed in the integrated molding resin, which forms the linking member 53 , the separate process steps of assembling the magnets 51 and press fitting the magnet cover 35 are no longer required. In addition, the assembly of the piston is completed by screwing the piston onto the piston coupling boss 52 .
[0042] The integrated piston operating assembly 50 reciprocates due to a changing magnetic field, which is generated by the internal lamination 13 and coil 15 disposed within the cylindrical arrangement of magnets 51 , and the external lamination 41 disposed outside the cylindrical arrangement of magnets 51 . When the piston operating assembly 50 reciprocates, the piston, which is coupled with the piston operating assembly 50 , also reciprocates linearly within the cylinder. Accordingly, the refrigerant is drawn into the compressing chamber and then compressed.
[0043] A method for manufacturing the piston operating assembly 50 for the linear compressor in accordance with the preferred embodiment of the present invention will be described below with reference to FIGS. 7-9.
[0044] As illustrated in FIG. 9, the method for manufacturing the integrated piston operating assembly 50 includes the steps of preparing a plurality of magnets 51 and a piston coupling boss 52 (step S 100 ), assembling the plurality of magnets 51 and the piston coupling boss 52 in a core mold 60 (FIGS. 7A and 7B) and mounting the core mold 60 in an injection molding machine (step S 200 ), integrally injection molding the piston operating assembly 50 with the plurality of magnets 51 and the piston coupling boss 52 (step S 300 ), and then separating the completed the piston operating assembly 50 for the linear compressor from the core mold 60 when the molding process is finished (step S 400 ).
[0045] In the preparation step S 100 , the magnets 51 and the piston coupling boss 52 , which are made by separate processes, are prepared for assembly into the core mold 60 . In this embodiment, one piston coupling boss 52 and eight magnets 51 are used. Accordingly, eight magnets 51 and one piston coupling boss 52 are prepared. The magnets 51 are initially non-magnetized magnets.
[0046] In the mold mounting step S 200 , the eight magnets 51 and the piston coupling boss 52 are assembled in the core mold 60 . The core mold 60 is then mounted between an upper mold 70 and a lower mold 80 of the injection molding machine. The core mold 60 has a plurality of linear projections 61 (FIGS. 7A and 7B) that are formed on the outer circumference thereof. The linear projections 61 extend parallel to the axis of the core mold 60 and are spaced apart at equal intervals to accommodate the magnets 51 . In order to magnetize the non-magnetic magnets 51 , additional magnets 62 are disposed within the core mold 60 . Further, a screw portion is formed at the center of the core mold 60 , to secure the piston coupling boss 52 . The piston operating assembly 50 of the present invention has less geometric error, for example, less error in concentricity, since a relatively shorter piston coupling boss 52 is secured thereto by injection molding. In contrast, in a conventional piston operating assembly, a longer piston is welded onto the linking member.
[0047] After the core mold 60 is mounted in the injection molding machine, the injection molding process begins. A molding resin is injected in the direction indicated by an arrow P in FIG. 8 into the core mold 60 . The molding resin fills in the area of the core mold 60 that is indicated by the cross-hatching in FIG. 8 to surround the piston coupling boss 52 and the magnets 51 . As a result, the integrated piston operating assembly 50 is formed at step S 300 . Gravity helps to draw the molding resin down through the gaps defined between the plurality of projections 61 of the core mold 60 to surround the magnets 51 , so that the magnets 5 1 are fixedly secured by the molding resin.
[0048] After a predetermined time period, the molding resin solidifies and cools. At step S 400 the completed piston operating assembly 50 is then removed from between the upper and lower molds 70 and 80 , respectively, of the injection molding machine.
[0049] The present method for manufacturing the piston operating assembly 50 improves the geometric and assembly tolerances of the resulting piston operating assembly, by eliminating forceful coupling methods for securing the piston coupling boss and the magnets to the linking member. The magnets 51 and the coupling boss 52 are each coupled to the linking member 53 as the linking member 53 is injection molded.
[0050] Furthermore, the present method for manufacturing the piston operating assembly 50 for the linear compressor improves productivity, since the numerous assembly process steps are simplified by injection molding. The L-shaped cross-section of the magnets 51 secures the magnets to the linking member 53 , thereby eliminating the need for a separate magnet cover. In addition, the piston is easily connected to the piston operating assembly 50 , by matingly engaging the threads at the end of the piston with the screw portion 52 b of the piston coupling boss 52 .
[0051] As stated above, a preferred embodiment of the present invention is shown and described. Although the preferred embodiment of the present invention has been described, it is understood that the present invention should not be limited to this preferred embodiment. Various changes and modifications can be made by one skilled in the art within the spirit and scope of the present invention as hereinafter claimed.
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An integrated piston operating assembly for a linear compressor and a method for manufacturing the same are provided. The integrated piston operating assembly includes a piston coupling boss coupled to a piston, a plurality of magnets disposed in a cylindrical arrangement concentric with the piston coupling boss, and a linking member formed of a resin for connecting and thus integrating the piston coupling boss with the plurality of magnets. The magnets and piston coupling boss are secured to the linking member as the linking member is injection molded. By integrating the piston operating assembly of the linear compressor, geometric and assembling tolerances are improved, while deterioration of persistence due to processing and assembling processes is prevented.
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BACKGROUND OF THE INVENTION
The subject matter described herein relates generally to methods and systems for operating a wind turbine or a wind farm, and more particularly, to methods and systems for operating a wind turbine or a wind farm under noise management.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extend from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
During operation of such known wind turbines, rotational transiting of the blades through air generates aerodynamic acoustic emissions in the form of audible noise. These acoustic emissions may produce noise with a decibel (dB) level that may approach or even exceed local regulatory levels. Accordingly, at least some methods exist for controlling noise from a wind turbine or a wind turbine installation including a plurality of wind turbines (i.e., a wind farm). In particular, a wind turbine may be operated such that produced noise is below predetermined dB parameters. Such an operation of a wind turbine for reducing acoustic emissions is also known as noise reduction operation (NRO) or operation under sound power management (SPM).
NRO typically implies that a wind turbine generates an electric power below the maximum possible power generation capacity of the wind turbine. Therefore, the operational state of a wind turbine under noise reduction operation is normally not directed to achieve a maximum power output but to comply with noise regulations applying to the wind turbine. However, during SPM, it is important to still yield the maximum amount of electric power that is possible under the prescribed regulations.
In practice, however, it turns out that the operation under SPM does not always lead to the desired results. In some cases, the resulting generated power is below that of what could be expected given the allowed noise power level. In yet further situations, the resulting noise does still exceed the allowed level although it should not. Hence, it is a desire to improve the operation under SPM, in particular, it is a desire to increase the power output of a wind turbine or a wind farm operating under SPM. It is also particularly desirable that the noise regulations are met during operation under SPM.
BRIEF DESCRIPTION OF THE INVENTION
In one aspect, a method for operating a wind turbine is provided. The wind turbine generates a sound level. The method includes selecting a desired sound level; calculating at least one operating parameter by inputting the desired sound level to a model; and operating the wind turbine according to the at least one operating parameter. The method further includes measuring the sound level and based on the measured sound level, calculating at least one of a redefined desired sound level and a revised model. Furthermore, the method includes calculating at least one redefined operating parameter by at least one of inputting the redefined desired sound level to the model and inputting the desired sound level to the revised model.
According to aspects, the method is performed in the sequence described.
In another aspect, a wind turbine is provided that includes a rotor with at least one rotor blade; a generator for converting kinetic energy supplied by the rotor into electric energy; and a control system for operating the wind turbine. The control system is configured to calculate at least one operating parameter by inputting a desired sound level to a model; operate the wind turbine according to the at least one operating parameter; obtain a measured sound level; based on the measured sound level, calculate at least one of a redefined desired sound level and a revised model; and calculate at least one redefined operating parameter for operating the wind turbine by one of inputting the redefined desired sound level to the model and inputting the desired sound level to the revised model.
Further aspects, advantages and features of the present invention are apparent from the dependent claims, the description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
A full and enabling disclosure including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures wherein:
FIG. 1 is a perspective view of an exemplary wind turbine.
FIG. 2 is an enlarged sectional view of a portion of the wind turbine shown in FIG. 1 .
FIG. 3 is a schematic diagram illustrating a noise map according to embodiments described herein.
FIG. 4 is a schematic diagram illustrating a noise inverse map according to embodiments described herein.
FIG. 5 is a schematic diagram illustrating the known operation of a wind turbine.
FIG. 6 is a schematic diagram illustrating the operation of a wind turbine according to embodiments described herein.
FIG. 7 is a schematic diagram illustrating the operation of a wind turbine according to embodiments described herein.
FIG. 8 is a schematic diagram illustrating the operation of a wind turbine according to embodiments described herein.
FIG. 9 is a schematic diagram illustrating the method for operating a wind turbine as described herein.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet further embodiments. It is intended that the present disclosure includes such modifications and variations.
The embodiments described herein include a wind turbine that can be operated under sound power management in an improved manner. More specifically, the operation of the wind turbine allows for yielding a high energy output given the allowed sound level under SPM. In addition, the operation of the wind turbine allows particularly for achieving the prescribed sound level emission requirements.
As used herein, the terms “sound power” and “noise” are used synonymously, and are intended to be representative of the overall acoustic emission of a wind turbine. Evidently, the sound power of a wind farm refers to the overall acoustic emission of a wind farm. As used herein, the term “blade” is intended to be representative of any device that provides a reactive force when in motion relative to a surrounding fluid. As used herein, the term “wind turbine” is intended to be representative of any device that generates rotational energy from wind energy, and more specifically, converts kinetic energy of wind into mechanical energy. As used herein, the term “wind generator” is intended to be representative of any wind turbine that generates electrical power from rotational energy generated from wind energy, and more specifically, converts mechanical energy converted from kinetic energy of wind to electrical power. The term “wind farm” refers to a plurality of wind turbines.
FIG. 1 is a perspective view of an exemplary wind turbine 10 . In the exemplary embodiment, wind turbine 10 is a horizontal-axis wind turbine. Alternatively, wind turbine 10 may be a vertical-axis wind turbine. In the exemplary embodiment, wind turbine 10 includes a tower 12 that extends from a support system 14 , a nacelle 16 mounted on tower 12 , and a rotor 18 that is coupled to nacelle 16 . Rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outward from hub 20 . In the exemplary embodiment, rotor 18 has three rotor blades 22 . In an alternative embodiment, rotor 18 includes more or less than three rotor blades 22 . In the exemplary embodiment, tower 12 is fabricated from tubular steel to define a cavity (not shown in FIG. 1 ) between support system 14 and nacelle 16 . In an alternative embodiment, tower 12 is any suitable type of tower having any suitable height.
Rotor blades 22 are spaced about hub 20 to facilitate rotating rotor 18 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy. Rotor blades 22 are mated to hub 20 by coupling a blade root portion 24 to hub 20 at a plurality of load transfer regions 26 . Load transfer regions 26 have a hub load transfer region and a blade load transfer region (both not shown in FIG. 1 ). Loads induced to rotor blades 22 are transferred to hub 20 via load transfer regions 26 .
In one embodiment, rotor blades 22 have a length ranging from about 15 meters (m) to about 91 m. Alternatively, rotor blades 22 may have any suitable length that enables wind turbine 10 to function as described herein. For example, other non-limiting examples of blade lengths include 10 m or less, 20 m, 37 m, or a length that is greater than 91 m. As wind strikes rotor blades 22 from a direction 28 , rotor 18 is rotated about an axis of rotation 30 . As rotor blades 22 are rotated and subjected to centrifugal forces, rotor blades 22 are also subjected to various forces and moments. As such, rotor blades 22 may deflect and/or rotate from a neutral, or non-deflected, position to a deflected position.
Moreover, a pitch angle or blade pitch of rotor blades 22 , i.e., an angle that determines a perspective of rotor blades 22 with respect to direction 28 of the wind, may be changed by a pitch adjustment system 32 to control the load and power generated by wind turbine 10 by adjusting an angular position of at least one rotor blade 22 relative to wind vectors. Pitch axes 34 for rotor blades 22 are shown. During operation of wind turbine 10 , pitch adjustment system 32 may change a blade pitch of rotor blades 22 such that rotor blades 22 are moved to a feathered position, such that the perspective of at least one rotor blade 22 relative to wind vectors provides a minimal surface area of rotor blade 22 to be oriented towards the wind vectors, which facilitates reducing a rotational speed of rotor 18 and/or facilitates a stall of rotor 18 .
In the exemplary embodiment, a blade pitch of each rotor blade 22 is controlled individually by a control system 36 . Alternatively, the blade pitch for all rotor blades 22 may be controlled simultaneously by control system 36 . Further, in the exemplary embodiment, as direction 28 changes, a yaw direction of nacelle 16 may be controlled about a yaw axis 38 to position rotor blades 22 with respect to direction 28 .
In the exemplary embodiment, control system 36 is shown as being centralized within nacelle 16 , however, control system 36 may be a distributed system throughout wind turbine 10 , on support system 14 , within a wind farm, and/or at a remote control center. Control system 36 includes a processor 40 configured to perform the methods and/or steps described herein. Further, many of the other components described herein include a processor. As used herein, the term “processor” is not limited to integrated circuits referred to in the art as a computer, but broadly refers to a control system, a microcontrol system, a microcomputer, a programmable logic control system (PLC), an application specific integrated circuit, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that a processor and/or a control system can also include memory, input channels, and/or output channels.
In the embodiments described herein, memory may include, without limitation, a computer-readable medium, such as a random access memory (RAM), and a computer-readable non-volatile medium, such as flash memory. Alternatively, a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), and/or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, input channels include, without limitation, sensors and/or computer peripherals associated with an operator interface, such as a mouse and a keyboard. Further, in the exemplary embodiment, output channels may include, without limitation, a control device, an operator interface monitor and/or a display.
Processors described herein process information transmitted from a plurality of electrical and electronic devices that may include, without limitation, sensors, actuators, compressors, control systems, and/or monitoring devices. Such processors may be physically located in, for example, a control system, a sensor, a monitoring device, a desktop computer, a laptop computer, a programmable logic control system (PLC) cabinet, and/or a distributed control system (DCS) cabinet. RAM and storage devices store and transfer information and instructions to be executed by the processor(s). RAM and storage devices can also be used to store and provide temporary variables, static (i.e., non-changing) information and instructions, or other intermediate information to the processors during execution of instructions by the processor(s). Instructions that are executed may include, without limitation, wind turbine control system control commands. The execution of sequences of instructions is not limited to any specific combination of hardware circuitry and software instructions.
FIG. 2 is an enlarged sectional view of a portion of wind turbine 10 . In the exemplary embodiment, wind turbine 10 includes nacelle 16 and hub 20 that is rotatably coupled to nacelle 16 . More specifically, hub 20 is rotatably coupled to an electric generator 42 positioned within nacelle 16 by rotor shaft 44 (sometimes referred to as either a main shaft or a low speed shaft), a gearbox 46 , a high speed shaft 48 , and a coupling 50 . In the exemplary embodiment, rotor shaft 44 is disposed coaxial to longitudinal axis 116 . Rotation of rotor shaft 44 rotatably drives gearbox 46 that subsequently drives high speed shaft 48 . High speed shaft 48 rotatably drives generator 42 with coupling 50 and rotation of high speed shaft 48 facilitates production of electrical power by generator 42 . Gearbox 46 and generator 42 are supported by a support 52 and a support 54 . In the exemplary embodiment, gearbox 46 utilizes a dual path geometry to drive high speed shaft 48 . Alternatively, rotor shaft 44 is coupled directly to generator 42 with coupling 50 .
Nacelle 16 also includes a yaw drive mechanism 56 that may be used to rotate nacelle 16 and hub 20 on yaw axis 38 (shown in FIG. 1 ) to control the perspective of rotor blades 22 with respect to direction 28 of the wind. Nacelle 16 also includes at least one meteorological mast 58 that includes a wind vane and/or an anemometer (neither shown in FIG. 2 ). According to aspects, mast 58 provides information to control system 36 that may include wind direction and/or wind speed. In the exemplary embodiment, nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62 .
Forward support bearing 60 and aft support bearing 62 facilitate radial support and alignment of rotor shaft 44 . Forward support bearing 60 is coupled to rotor shaft 44 near hub 20 . Aft support bearing 62 is positioned on rotor shaft 44 near gearbox 46 and/or generator 42 . Alternatively, nacelle 16 includes any number of support bearings that enable wind turbine 10 to function as disclosed herein. Rotor shaft 44 , generator 42 , gearbox 46 , high speed shaft 48 , coupling 50 , and any associated fastening, support, and/or securing device including, but not limited to, support 52 and/or support 54 , and forward support bearing 60 and aft support bearing 62 , are sometimes referred to as a drive train 64 .
In the exemplary embodiment, hub 20 includes a pitch assembly 66 . Pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70 . Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in FIG. 1 ) for modulating the blade pitch of associated rotor blade 22 along pitch axis 34 . Only one of three pitch drive systems 68 is shown in FIG. 2 .
In the exemplary embodiment, pitch assembly 66 includes at least one pitch bearing 72 coupled to hub 20 and to respective rotor blade 22 (shown in FIG. 1 ) for rotating respective rotor blade 22 about pitch axis 34 . Pitch drive system 68 includes a pitch drive motor 74 , pitch drive gearbox 76 , and pitch drive pinion 78 . Pitch drive motor 74 is coupled to pitch drive gearbox 76 such that pitch drive motor 74 imparts mechanical force to pitch drive gearbox 76 . Pitch drive gearbox 76 is coupled to pitch drive pinion 78 such that pitch drive pinion 78 is rotated by pitch drive gearbox 76 . Pitch bearing 72 is coupled to pitch drive pinion 78 such that the rotation of pitch drive pinion 78 causes rotation of pitch bearing 72 . More specifically, in the exemplary embodiment, pitch drive pinion 78 is coupled to pitch bearing 72 such that rotation of pitch drive gearbox 76 rotates pitch bearing 72 and rotor blade 22 about pitch axis 34 to change the blade pitch of blade 22 .
Pitch drive system 68 is coupled to control system 36 for adjusting the blade pitch of rotor blade 22 upon receipt of one or more signals from control system 36 . In the exemplary embodiment, pitch drive motor 74 is any suitable motor driven by electrical power and/or a hydraulic system that enables pitch assembly 66 to function as described herein. Alternatively, pitch assembly 66 may include any suitable structure, configuration, arrangement, and/or components such as, but not limited to, hydraulic cylinders, springs, and/or servo-mechanisms. Moreover, pitch assembly 66 may be driven by any suitable means such as, but not limited to, hydraulic fluid, and/or mechanical power, such as, but not limited to, induced spring forces and/or electromagnetic forces. In certain embodiments, pitch drive motor 74 is driven by energy extracted from a rotational inertia of hub 20 and/or a stored energy source (not shown) that supplies energy to components of wind turbine 10 .
According to aspects described herein, the wind turbine includes a sound measurement device 95 . The sound measurement device may be positioned at some distance from the tower 12 , for instance, at a distance of at least 100 m, or at a distance of at least 200 m. The sound measurement device may be placed, for instance, downwind with respect to the standard wind direction. Generally, under sound power management control, the wind turbine is not allowed to exceed a permissible sound level. The permissible sound level may vary dependent on the time of day or night, or dependent on the wind direction, the wind power etc. Typically, the permissible sound level is prescribed in national, regional or local regulations. The noise impact to people living in the neighborhood of the wind turbines shall be limited.
Despite the limited allowance to operate the wind turbine at full power, it is desirable to yield the maximum amount of energy given the allowed sound level. That is, in view of the allowed power level it is desirable to find the operating parameters of the wind turbine that allow the maximum power output. The operating parameters of the wind turbine that are of interest for this purpose are particularly the pitch angle, the rotational speed of the rotor, the desired power and the torque.
According to aspects described herein, the generated sound level is measured. Sound level measurement is typically undertaken at a distance from the wind turbine, such as at a distance of hub height plus half of the rotor diameter away from the wind turbine. The distance is typically selected in dependence of the hub height, the rotor diameter and/or the rated power. However, it is also possible to measure the sound level at the wind turbine which might allow for conclusions on the sound distribution in the vicinity of the wind turbine. Measuring the sound level typically includes directly the sound level, e.g., by means of a microphone, or indirectly determining the sound level, e.g., by calculating the sound level on the basis of a model to which data such as speed, pitch angle, atmospheric measurement, torque etc are typically inputted.
The measured sound is transmitted to the control system of the wind turbine. The control system takes the feedback signal into account when determining the operating parameters of the wind turbine such as, but not limited to, the optimal speed set-points, the optimal pitch offsets, the desired power and/or the optimal torque.
The benefit of the proposed scheme is an increase in the precision of control and thus an increase in the energy yielded under the sound power management control scheme in view of the given noise regulations.
The sound level model shall be explained with respect to the following figures. To start with, as illustrated in FIG. 3 , sound model 111 consists of a function 100 that maps a pitch angle 120 , a tip speed 110 and a wind speed 130 to an associated sound level 140 . That is, the function 100 calculates how much noise the turbine would generate at any given pitch angle, tip speed, and wind speed. Generally, and not limited to this embodiment, the function 100 may be a static function, i.e. described by algebraic equations, or a dynamic function, i.e., described by (partial) differential equations, recurrence equations, difference equations or state automata. In embodiments, it may be thus necessary to provide a memory for calculating the dynamic function.
In particular, the function 100 may be used to calculate the associated sound level 140 based on the optimal pitch angle and tip speed for all possible wind speeds. The “optimal pitch angle” and the “optimal tip speed” are defined as the pitch and tip speed setting that maximize the power generated under given wind conditions and the permissible sound level. The function 100 is usually obtained by running a couple of offline numerical optimization problems under appropriate software. The function 100 is supposed to represent the real world, that is, the noise generated by a real world turbine if operated at the given parameters.
Generally, and not limited to the present embodiment, the term “sound level” may particularly include the sound power level or the sound pressure. Typically, the sound level is directly measured by means of a sound measurement device, such as a microphone or the like. Alternatively it is possible to deduce the sound level by way of calculation from other measurements.
The model 111 illustrated with respect to FIG. 3 can be used for defining an appropriate noise inverse map 222 illustrated with respect to FIG. 4 . The inverse function 200 defines a new function that outputs the respective settings such as the tip speed and pitch setting to be applied to a real wind turbine based on a desired level of sound. In more detail, as exemplarily illustrated in the figure, the desired maximal sound level 210 is inputted to the inverse function 200 . In the embodiment illustrated, the desired maximal sound level 210 is a function in dependence of the wind speed but could generally be dependent also on other variables. Given the measured wind speed 230 , the inverse function 200 determines the corresponding pitch angle 240 and the rotor blade tip speed 220 .
The noise inverse function 200 as illustrated with respect to FIG. 4 is usually obtained by numerical methods based on the noise function 100 as exemplarily illustrated with respect to FIG. 3 .
The conventional sound level control scheme is shown in FIG. 5 . Given a desired sound level 210 and a given wind speed 230 , the noise inverse function 200 calculates the corresponding wind turbine settings such as, but not limited to, the pitch angle 240 and tip speed 220 . These values are used for the operation of the wind turbine 10 . The wind turbine control thus adjusts the respective settings. For instance, it may pitch the blades.
Given the operation under the settings 220 and 240 as well as under the given wind conditions, the turbine generates an amount of noise which is illustrated as the sound level 340 in FIG. 5 .
In theory, the desired noise power level 210 and the sound level 340 emitted by the wind turbine should be identical. This is because the noise inverse function 200 should be, in theory, the function that is inverse to what sound level the wind turbine produces at a given wind speed.
However, experience shows that, in practice, there are differences between the desired sound level 210 and the emitted sound level 340 . There can be several reasons for this. One reason can be that the computer model and the real system do not match exactly. That is, the noise function 100 and consequently the noise inverse function 200 do not fully comply with the reality. For instance, the theoretical calculation of the emitted sound level is 5% below what the real sound emission level is. In this case, the turbine is operated with prohibited noise emissions. Another reason can be that the wind speed is not measured with the necessary accuracy, that is, the wind speed level 230 as illustrated in the present figures does not fully match the real wind speed.
Hence, as a result of these obstacles, in practice there is a mismatch between the desired sound level and the factual emitted sound level is persistent. This mismatch can have various negative effects. For instance, the wind turbine could operate at a lower efficiency level than the one corresponding to the desired sound level. This causes commercial disadvantage. Another effect could be that the actual sound level exceeds the desired and permissible sound level, which causes undue sound annoyance for the neighbors. Furthermore, in case of a repeated excess of the permissible sound level, the wind turbine operator might be forced to drastically reduce the operation or even shut down the wind turbine.
Hence, in order to address those issues, according to aspects described herein, a feedback signal of the sound level is employed in order to reduce or eliminate the mismatch between the theoretical mapping and the real world situation. According to embodiments, both the measured noise and a modeled noise are used for the control of the wind turbine.
A possible proposed scheme is shown in FIG. 6 . The sound level 340 is measured and fed back to a control system 36 , which properly updates the operating parameters of the wind turbine with information such as the tip speed, torque, power and/or pitch setting. As illustrated in FIG. 6 , the feedback line 310 allows for the feeding back of the sound level 340 to the control system 36 . The control system 36 is configured to calculate the noise inverse function, referred to by reference number 200 in the other figures. In addition, the control system may be configured to calculate a mismatch between the desired sound level 210 and the actual sound level 340 . The mismatch is then considered when the turbine settings are calculated, such as the pitch angle 240 or the tip speed 220 .
According to embodiments, the feedback line 310 is active only if the difference between the actually generated noise 340 and the desired sound level 210 is non-zero. Alternatively, in case there is no mismatch between the sound level 140 and the desired sound level 210 , the feedback line 310 may send a signal corresponding to zero.
In the following, it shall exemplarily be explained in more detail how the feedback is performed. In case there is a mismatch between the desired sound level 210 and the actual sound level 340 , the control system 36 re-defines the desired sound level 210 as follows:
L c =L d −( L m −L M ) (1)
In this equation (1), L c refers to the re-defined sound level that is subsequently inputted to the inverse function 200 as basis for the calculation of corrected turbine settings. L d refers to the desired sound level which is referred to by reference number 210 in the figures. L m refers to the measured sound level which is referred to by reference number 340 in the figures. L M refers to the sound level according to the noise function that was referred to by reference number 100 previously. This sound level is referred to by reference number 140 in FIG. 3 .
FIG. 7 illustrates an embodiment for a method as described herein. The control system 36 receives the actual wind speed 230 . In addition, the desired sound level 210 may be inputted to the control system 36 , or, if a feedback signal is already available, the re-defined desired sound level 430 . For instance, if there is no feedback signal available (maybe because the operation of the turbine has started shortly before or because there is no mismatch between the desired sound level and the actually generated sound level), the desired sound level 210 is equal to the re-defined sound level 430 . However, in the case that there is a feedback signal, the re-defined sound level 430 is calculated as described, i.e. the redefinition factor 420 , calculated as L m −L m , is subtracted from the desired sound level 210 thus yielding to the re-defined desired sound level 430 . The re-definition factor 420 corresponds to the parenthesis in the equation (1).
In FIG. 7 , a first subtractor 400 serves to subtract the re-definition factor 420 from the desired sound level 210 . In other words, the first subtractor 400 calculates L c according to equation (1).
According to typical embodiments, the first subtractor 400 is part of the control system 36 although, for clarity reasons, it is shown separately from the control system 36 in FIG. 7 . Thus, the control system is typically configured to calculate the corrected sound level L c . In addition, the control system is configured to calculate the corresponding turbine settings based on an inputted desired sound level.
According to aspects described herein, at least when there is a feedback signal, the control system does not calculate the wind turbine settings on the basis of the given desired sound level L d , referred to as number 210 , but, instead, uses the corrected sound level L c , referred to as number 430 as a basis for the calculation of the wind turbine settings such as the pitch angle 240 , the tip speed 220 , the torque (omitted in the drawings in order to facilitate reading) or the like.
The control system 36 thus bases its calculation of the turbine settings on an ‘incorrect’ desired sound level in the sense that this sound level is different from the desired sound level L d . In other words, according to an aspect, the concept of the present disclosure is not to use the feedback signal and the mismatch information thereof for an improvement of the underlying noise function but, instead, to accept that the theoretic noise function 200 does not perfectly match the real world and to avoid discrepancies nevertheless by feeding re-defined desired sound levels to the calculation. These re-defined sound levels differ from the actually desired sound level according to the theoretic noise inverse function 200 .
For instance, in theory, that is according to the noise inverse function 200 , the re-defined sound level might even be higher than the actually allowed sound level. Nevertheless, given the discrepancies between the real world system 100 and the theoretic noise inverse function 200 , this re-defined sound level might lead to turbine settings that exactly meet the allowed noise power level in practice.
According to another aspect of the present disclosure, the feedback signal and the mismatch information associated therewith are used for improving the underlying noise function, in particular, to adjust the internal parameters of the model. For instance, the noise function may be adapted once there is a feedback signal indicating a mismatch in an iterative manner.
The control system 36 calculates the corresponding wind turbine settings such as, but not limited to, the pitch angle 240 and the rotor blade tip speed 220 . Based on this information, the wind turbine operates according to the respective wind turbine settings. Thereby, the wind turbine produces noise which is shown as the sound level 340 .
In addition, the calculated turbine settings such as the pitch angle 240 and the rotor blade tip speed 220 (as well as further parameters which were omitted for clarity reasons in the figures) are supplied to noise function 100 that maps the wind turbine settings, along with the wind speed 230 , to the theoretically associated sound level 140 which was named L M in the previous equation (1).
According to the embodiment shown in FIG. 7 , a second subtractor 440 is provided that subtracts the modeled sound level L M , referred to by reference number 140 , from the measured sound level L m , referred to by reference number 340 . As set forth previously, the resulting correction factor L m −L M , referred to by reference number 420 in FIG. 7 , is then provided, directly or via the first subtractor 400 , to the control system 36 . According to other embodiments, the control system 36 is used for the subtraction of the modeled sound level L M , referred to by reference number 140 , from the measured sound level L m , referred to by reference number 340 instead of a specific subtractor.
FIG. 8 illustrates an embodiment wherein the complete calculation is done by one control system, that is, control system 36 . Typically, the control system is the control system of the wind turbine. The control system receives the desired sound level L d , referred to by number 210 , the measured sound level L m , referred to by number 340 , and the modeled sound level L M , referred to by number 140 . The sound level may refer, for instance, to a sound power level, a sound pressure level, or any other relevant noise measurement. Generally, and not limited to the present embodiment, the models can be static. According to other embodiments, the models can be dynamic
The control system calculates the corrected sound level L c and inputs it into the noise inverse function as explained with respect to previous figures. The outcome is turbine settings, such as, the pitch angle 240 , the wind blade tip speed 220 , torque settings (not shown) or other settings for operating the wind turbine.
FIG. 9 illustrates a method for operating a wind turbine according to embodiments described herein. In block 500 , a desired sound level L d is selected. For instance, and not limited to the present embodiment but applicable to all embodiments described herein, the desired sound level L d can be selected by an operator, it may be retrieved from a database, or it may be retrieved from a processor outputting the desired sound level. For instance, some regulations prescribe reduced sound emission at night. Hence, the desired sound level might be adjusted according to the time of the day. Also, the regulations may vary dependent on the seasons, the weather or the like.
The desired sound level may be chosen in dependence of the wind speed and/or the ambient noise. For instance, for each value of the wind speed, a selected sound level should be achieved. According to embodiments, the desired sound level is a function of the ambient noise. For instance, if the ambient noise is high, the desired sound level may be selected high compared to a situation with low ambient noise. Hence, according to embodiments described herein, the wind turbine may further include a sound measurement device for measuring the ambient noise.
According to the next block 510 , the noise inverse function (referred to as reference number 200 in previous figures) is used to calculate the respective turbine settings for operating the turbine from the desired sound level L d , typically under consideration of the actual wind speed. The turbine settings particularly include the pitch angle, the tip speed, and the torque.
According to the next block 520 , the calculated turbine settings are used for operating the wind turbine. Possibly, but not necessarily at the same time, according to block 530 , the calculated turbine settings are inputted to the noise function that has been referred to as reference number 100 in previous figures. The noise function therefrom calculates the theoretic sound level L M . According to embodiments, the sound pressure level is calculated instead of the sound level and compared with the respective measured sound pressure level.
According to block 540 , the actual sound level L m is measured. Typically, a certain amount of time is waited between amending the wind turbine settings and measuring the generated noise in order to obtain a realistic measurement value referring to the operation at the desired settings, and not a measurement value relating to the transition time between the different operational modes.
According to block 550 , the measured sound level is compared to the desired sound level L d . In the event that they are identical, no changes need to be made to the settings. Hence, it is possible to stop the method, that is, to proceed to block 570 which represents the end. Alternatively, it is possible to wait for a selected amount of time, such as between 1 and 100 minutes, typically between 10 and 50 minutes, depending on the turbine and the application, before restarting the procedure again. For instance, if the desired sound level L d has not changed, the method is continued with block 510 , i.e. the calculation of the turbine settings, or with block 520 , i.e. the measurement of the actual wind speed. In those cases where the desired sound level L d is reset (for instance, because a specific time of the day is reached), it is possible to restart the method with block 500 again (this alternative is not shown in FIG. 9 ).
In case there is a mismatch between the desired sound level L d and the measured sound level L m , a re-defined desired sound level L c is calculated in block 560 . The calculation is performed as described previously and particularly with reference to equation (1). The re-defined sound level L c is used for the calculation of the subsequent wind turbine settings. Thus, instead of taking the desired sound level L d as basis for the calculation of the wind turbine settings, the re-defined desired sound level L c is taken, and the method is repeated under this condition. This is shown in FIG. 9 wherein the connection from block 560 to block 500 shall indicate that the re-defined desired sound level is used as the new desired sound level.
The method can be repeated as long as the desired wind power level is not identical to the measured sound level. The term “identical” in this sense shall include deviations of 3% at maximum, typically of 1% or even 0.5% at minimum (in terms of decibel (db)). It is not shown in FIG. 9 , however, it is possible to stop the method, for instance, when wind conditions are such that the turbine has to be stopped, or in the event that the night is over and normal power optimized operation of the turbine is possible again. Generally, and not limited to this embodiment, the calculation of the settings and the control of the turbine may be influenced by further circumstances such as the time of day, change in the wind (strength and direction), number of gusts etc. It is furthermore possible according to the embodiments described herein that the method is stopped if the wind speed is decreasing and thus leading to noise emissions that are clearly allowable under energy optimized control.
The above-described systems and methods facilitate and improve the control of one or more wind turbines under SPM. More specifically, they allow for better adherence to the regulations whilst improving the energy yield at the same time.
Exemplary embodiments of systems and methods for one or more wind turbines are described above in detail. The systems and methods are not limited to the specific embodiments described herein, but rather, components of the systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the invention (including the best mode) and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. While various specific embodiments have been disclosed in the foregoing, those skilled in the art will recognize that the spirit and scope of the claims allows for equally effective modifications. Especially, mutually non-exclusive features of the embodiments described above may be combined with each other. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
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A method for operating a wind turbine is provided. The wind turbine generates a sound level. The method includes selecting a desired sound level; calculating at least one operating parameter by inputting the desired sound level to a model; and operating the wind turbine according to the at least one operating parameter. The method further includes measuring the sound level and based on the measured sound level, calculating at least one of a redefined desired sound level and a revised model. Furthermore, the method includes calculating at least one redefined operating parameter by at least one of inputting the redefined desired sound level to the model and inputting the desired sound level to the revised model.
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FIELD OF THE INVENTION
This invention relates generally to the field of chemical mechanical polishing (CMP) of semiconductor wafers or substrates. More specifically, the invention relates to a method of chemical mechanical polishing of semiconductor wafers or substrates.
BACKGROUND OF THE INVENTION
The ever-increasing demand for high-performance microelectronic devices has motivated the semiconductor industry to design and manufacture Ultra-Large-Scale Integrated (ULSI) circuits with smaller feature size, higher resolution, denser packing, and multi-layer interconnects. The ULSI technology places stringent demands on global planarity on multiple layers, called Interlevel Dielectric (ILD) layers, which comprise the circuit. Compared with other planarization techniques, the chemical mechanical polishing (CMP) process produces excellent local and global planarization at low cost, and is thus widely adopted in many back-end processes for planarizing inter-level dielectric layers, which are most often silicon dioxide (SiO 2 ). In addition to achieving global planarization, CMP is also critical to many emerging process technologies, such as the polishing of copper (Cu) damascene patterns, low-k dielectrics, and shallow trench isolation (STI) structures (Landis et al., 1992; Peters, 1998). The wide range of materials to be polished concurrently or sequentially, however, increases the complexity of the CMP process and necessitates an understanding of the process fundamentals for optimal process design and control.
Despite its extensive use in ULSI manufacturing, the basic material removal mechanisms in CMP are not yet well understood. Long ago, Preston empirically found in glass polishing that the material removal rate (MRR) is proportional to the product of the applied pressure and the relative velocity (Preston, 1927). The Preston equation may be written as ξ t = k p p v R
where ξ is the thickness of the layer removed, t the polishing time, p the nominal pressure, v R the relative velocity, and k p is a constant known as the Preston constant.
In recent years, it has been demonstrated in many works that the above relation is also valid for metals (Steigerwald et al., 1994; Stavreva et al., 1995 and 1997) and ceramics (Nakamura et al., 1985; Komanduri et al., 1996). To explain this proportionality, researches have attempted to study the material removal mechanisms during the CMP process, and several researchers have proposed particle abrasion (Brown et al., 1981; Liu et al., 1996) and pad asperity contact models (Yu et al., 1993) to elucidate the mechanical aspects of the CMP process. Assuming that wafer/abrasive or wafer/pad is in contact, the applied stress field near the wafer surface results in elastic-plastic deformation of the surface layer and produces wear. Another line of research has focused on the chemical mechanisms of the process (Cook, 1990; Luo et al., 1998). Cook first reviewed the chemical process for glass polishing. He suggested that both surface dissolution under particle impact and the absorption or dissolution of wear particles onto the slurry particles will determine the polishing rate of glass. More recently, a two-dimensional wafer-scale model based on lubrication theory (Runnels and Eyman, 1994) and mass transport has been proposed (Sundararajan et al., 1999). In this model, the wafer is assumed to hydroplane on the pad surface, and the normal load is supported by the hydrodynamic pressure of the viscous slurry film. The polishing rate is determined by the convective mass transport of the chemical species.
Whether material removal is by mechanical, chemical, or chemomechanical interactions in the CMP process, an understanding of the contact condition at the wafer/pad interface is important to process characterization, modeling, and optimization. However, to date there is no explicit methodology in the CMP literature to characterize wafer-scale interfacial conditions with process parameters. Some researchers have assumed that the wafer hydroplanes while being polished, and thus solve the Reynolds equation of lubrication to determine the relations among wafer curvature, applied pressure, relative velocity, slurry viscosity, slurry film thickness, and pressure distribution on the wafer surface (Runnel, 1994; Runnel and Eyman, 1994). Another group has assumed the wafer is in contact, or partially in contact with the pad, and relate the displacement of the wafer to the pad elastic modulus and solve the stress field by the classical contact mechanics model (Chekina et al., 1998). Measurement of the vertical displacement of the wafer relative to the pad seems the most direct prior art technique of identifying the contact condition and determine the slurry film thickness (Mess et al., 1997). However, the compliance of the pad material and that of the back film in the wafer carrier make such measurements unreliable. While some experiments in the hydroplaning mode have been conducted on smaller specimens (Nakamura et al., 1985), it is questionable to scale up the results to a larger size wafer. In general, different applied pressure, velocity, and other experimental conditions employed by the various investigators have resulted in a difficult situation to draw any definitive conclusions regarding the mode of interfacial contact. Thus, it is highly desirable to determine and characterize the primary material removal mechanism during CMW and to provide a CMU process that promote an increased material removal rate (MRR) from the surface of the wafer.
Relevant Literature
References discussing CMP processes in the semiconductor industry include:
Bhushan, M., Rouse, R., and Lukens, J. E., 1995, “Chemical-Mechanical Polishing in Semidirect Contact Mode,” J Electrochem. Soc., Vol. 142, pp. 3845-3851.
Bramono, D. P. Y., and Racz, L. M., 1998, “Numerical Flow-Visulization of Slurry in a Chemical Mechanical Planarization Process,” Proc. 1998 CMP - MIC Conf. , pp. 185-192.
Brown, N. J., Baker, P. C., and Maney, R. T., 1981, “Optical Polishing of Metals,” Proc. SPIE, Vol. 306, pp. 42-57.
Bulsara, V. H., Ahn, Y., Chandrasekar, S., Farris, T. N., 1998, “Mechanics of Polishing,” ASME Journal of, Applied Mechanics, Vol. 65, pp. 410-416.
Chekina, O. G., Keer, L. M., and Liang, H., 1998, “Wear-Contact Problems and Modeling of Chemical Mechanical Polishing,” J. Electrochem. Soc., Vol. 145, pp. 2100-2106.
Cook, L. M., 1990, “Chemical Processes in Glass Polishing,” J. Non - Crystalline Solids , Vol. 120, pp. 152-171.
Cook, L. M., Wang, F., James, D. B., and Sethuraman, A. B., 1995, “Theoretical and Practical Aspects of Dielectric and Metal Polishing,” Semiconductor International, Vol. 18, pp. 141-144.
Komanduri, R., Umehara, N., and Raghanandan, M., 1996, “On the Possibility of Chemo-Mechanical Action in Magnetic Float Polishing of Silicon Nitride,” ASME, Journal of Tribology, Vol. 118, pp. 721-727.
Kaufman, F. B., Thompson, D. B., Broadie, R. E., Jaso, M. A., Guthrie, W. L., Pearson, D. J., and Small, M. B., 1991, “Chemical-Mechanical Polishing for Fabricating Patterned W Metal Features as Chip Interconnects,” J. Electrochem. Soc., Vol. 138, pp. 3460-3464.
Landis, H., Burke, P., Cote, W., Hill, W., Hoffman, C., Kaanta, C., Koburger, C., Lange, W., Leach, M., Luce, S., 1992, “Intergration of Chemical-Mechanical Polishing into CMOS Integrated Circuit Manufacturing,” Thin Solid Films, Vol. 220. pp. 1-7
Liu, C. -W., Dai, B. -T., Tseng, W. -T., and Yeh, C. -F., 1996, “Modeling of the Wear Mechanism during Chemical-Mechanical Polishing,” J. Electrochem. Soc., Vol. 143, pp. 716-721.
Luo, Q., Ramarajan, S., and Babu, S. V., 1998, “Modification of Preston Equation for the Chemical-Mechanical Polishing of Copper,” Thin Solid Films, Vol. 335, pp. 160-167.
Nakamura, T., Akamatsu, K., and Arakawa, N., 1985, “A Bowl Feed and Double Sides Polishing for Silicon Wafer for VLSI,” Bulletin Japan Soc. Precision Engg. , Vol. 19, pp. 120-125.
Peters, L., 1998, “Pursuing the Perfect Low-k Dielectric,” Semiconductor International, Vol. 21, pp. 64-74.
Runnels, S. R., 1994, “Feature-Scale Fluid-Based Erosion Modeling for Chemical-Mechanical Polishing,” J. Electrochem. Soc., Vol. 141, pp. 1900-1904.
Runnel, S. R., and Eyman, L. M., 1994, “Tribology Analysis of Chemical-Mechanical Polishing,” J. Electrochem. Soc., Vol. 141, pp. 1698-1701.
Runnels, S. R., Kim, I., Schleuter, J., Karlsrud, C., and Desai, M., 1998, “A Modeling Tool for Chemical-Mechanical Polishing Design and Evaluation,” IEEE Tran. on Semiconductor Mfg., Vol. 11, pp. 501-510.
Stavreva, Z., Zeidler, D., Plotner, M., Drescher, K., 1995, “Chemical Mechanical Polishing of Copper for Multilevel Metallization,” Appl. Surface Sci., Vol. 91, pp. 192-196.
Stavreva, Z., Zeidler, D., Plotner, M., Grasshoff, G., Drescher, K., 1997, “Chemical-Mechanical Polishing of Copper for Interconnect Formation,” Microelectronic Engr., Vol. 33, pp. 249-257.
Steigerwald, J. M., Zirpoli, R., Murarka, S. P., Price, D., Gutmann, R. J., 1994, “Pattern Geometry Effects in the Chemical-Mechanical Polishing of laid Copper Structures,” J Electrochem. Soc., Vol. 141, pp. 2842-2848.
Sundararajan, S., Thakurta, D. G., Schwendeman, D. W., Murarka, S. P., and Gill, W. N., 1999, “Two-Dimensional Wafer-Sacle Chemical Mechanical Planarization Models Based on Lubrication Theory and Mass Transport,” J. Electrochem. Soc., Vol. 146, pp. 761-766.
Yu, T. -K., Yu, C. C., and Orlowski, M., 1993, “A Statistical Polishing Pad Model for Chemical-Mechanical Polishing,” Proc. 1993 IEEE Int. Electron Dev. Mfg., pp. 865-868.
Zhao, B., and Shi, F. G., 1999, “Chemical Mechanical Polishing in IC Process: New Fundamental Insights,” Proc. 1999 CMP - MIC Conf, pp. 13-22.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a method of chemical mechanical polishing (CMP) that promotes increased material removal rate (MRR). More particularly, it is an object of the present invention to provide a method which operates in a contact mode at the interface between the CMP polishing pad and the wafer or substrate surface. Further, the present invention provides a method which identifies preferred CMP process parameters for increasing the MRR.
As will be described in detail below, the inventors have discovered that to increase the material removal rate, the CMP process must be operated in the contact mode at the interface between the wafer and the polishing pad. Hydroplaning at the interface is not a stable process mode in terms of the gimbaling point location, wafer curvature, and fluctuations in slurry flow. Accordingly, the important issue in CMP process design is to select process parameters to maintain the process in the stable contact regime. Further, the inventors have discovered that, within the contact mode, preferred process parameters may be identified according to a mathematical derivation as described below.
In general, a method of chemical mechanical polishing a surface of a wafer with a polishing pad is provided, comprising the steps of: rotating any one or both of the polishing pad and the wafer at a relative velocity v R ; and urging the wafer and pad against each other at an applied pressure p, wherein the values of p and v R are such that the interface between the pad and the wafer are in the contact mode.
In another aspect of the present invention, a method of chemical mechanical polishing is provided where the following equation is satisfied:
v R /P≈C 1 /η (1)
where v R is the relative velocity of the polishing pad and the wafer, p is the pressure applied to the wafer, and C 1 , is a constant that is related to the geometry of the polishing interface and machine design, and η is the viscosity of the slurry used in the particular CMP process, as described further below.
In a further aspect of the present invention, a method of chemical mechanical polishing is provided wherein the interfacial friction coefficient is monitored during the CMP process to maintain the interface between the wafer and the pad in the contact mode, and preferably to maintain the CMP process at the preferred operating parameters. For example, method of chemical mechanical polishing a surface of a wafer with a polishing pad is provided comprising the steps of: rotating any one or both of the polishing pad and the wafer at a relative velocity v R ; urging the wafer and pad against each other at an applied pressure p; measuring the frictional forces generated by the pad and wafer during the polishing; determining the friction coefficient from said friction measurement; and controlling the values of p and v R to maintain the friction coefficient at a value of about 0.1 or greater during polishing.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become apparent upon reading the detailed description of the invention and the appended claims provided below, and upon reference to the drawings, in which:
FIGS. 1A-1C are schematic diagrams of the wafer/pad interface at the contact mode, mixed mode and hydroplaning mode, respectively.
FIG. 2 is a graph showing the effect of the energy flux on Cu removal rate.
FIG. 3 is a graph illustrating the effect of the energy flux on the Preston constant.
FIG. 4A shows the effect of the dimensional parameter on the normalized Cu removal rate.
FIG. 4B illustrates the effect of the dimensional parameter on the Preston constant.
FIG. 5 is a graph illustrating the effect of the dimensional parameter on the friction coefficient.
FIG. 6 shows the correlation between the Preston constant and the friction coefficient.
FIG. 7 illustrates the velocity as a function of pressure and shows preferred parameters that may be selected according to one aspect of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The following nomenclature is used throughout the description of the present invention and is defined as:
k p
=
Preston constant (m 2 /N)
P
=
the rate of thermal energy generation due to friction (W)
p
=
normal pressure on wafer (N/m 2 )
p*
=
optimal normal pressure (N/m 2 )
r p ,r w
=
distances between a given point on the wafer and the
centers of the pad and the wafer (m)
v R *
=
optimal relative velocity (m/s)
v R
=
magnitude of the relative velocity (m/s)
η
=
viscosity of the slurry (Pa · s)
μ
=
Coulomb friction coefficient
μ a , μ l , μ p
=
friction coefficients
ξ
=
thickness of the material removed on wafer surface (m)
C
=
specific heat (J/kg · K)
The inventors have discovered that the material removal rate (MRR) of the chemical mechanical polishing (CMP) process is improved when the process is carried out such that the interface condition between the wafer or substrate surface and the CMP polishing pad (wafer/pad interface) are in the contact mode or contact regime. In particular, as described in further detail below, during the CTMP process three modes may exist at the interface of the pad and wafer; namely, the contact, hydroplaning and mixed modes. Referring to FIGS. 1A to 1 C, schematic diagrams illustrating the wafer/pad interface in the contact, mixed and hydroplaning modes, respectively, are shown. A CMP machine, such as those well known in the art, is used to polish the wafer or substrate. In general, the CMP machine usually includes one or more polishing stations which supports the polishing pad and a wafer carrier assembly which supports the wafer. One example of a CMP machine that may be used to practice the method of the present invention is described in U.S. patent application Ser. No. 09/628,563 filed simultaneously herewith, and incorporated by reference herein in its entirety. While one specific example is given, it will be understood by those of ordinary skill in the art that any suitable CMP machine may be used to practice the method of the present invention.
To planarize and/or polish the surface of the wafer, the wafer is urged against the polishing pad with an applied pressure p. The polishing pad has an abrasive surface and a slurry is typically placed on the pad to aid in material removal from the surface of the wafer. The wafer is typically rotated, and the polishing pad moves either linearly or may rotate as well, such that the wafer will experience a relative velocity v R . When the wafer is pressed against the polishing pad and slid with an intervening fluid layer, the polishing slurry at the wafer/pad interface, the interfacial conditions can be characterized as: contact, hydroplaning and mixed mode. In the contact mode shown in FIG. 1A, the asperities of opposing surfaces, wafer/pad or wafer/particle, mechanically interact. Usually, the real contact area is much smaller than the nominal surface area. Plastic deformation occurs on both surfaces at the contact spots. In the contact mode, the intervening fluid film is discontinuous and no significant pressure gradient will be formed in the fluid film across the diameter of the wafer to support the normal load. This type of contact mode occurs in the CMP practice when the relative velocity is low or the applied pressure is high. Since a tangential force is required to shear the surface asperities, the friction coefficient is relatively higher than that of the other two modes. In the contact mode the friction coefficient is generally in the range of about 0.1 or greater.
In contrast, when the velocity is sufficiently high or the applied pressure is relatively low, the wafer will glide on a fluid film without directly touching the pad. This is the hydroplaning mode and is illustrated in FIG. 1 C. Since there is no contact between the wafer and pad surfaces, the frictional force is due to the shear of the viscous fluid film, and the friction coefficient is expected to be much smaller than in the contact mode. In the hydroplaning mode the friction coefficient is found to be generally in the range of about 0.001 to 0.01. During polishing, pressure builds up in the viscous fluid film to support the normal load on the wafer. It may be noted that the pressure gradient is very sensitive to the wafer attack angle. A slight change of the attack angle, unsteady slurry flow, or a partial wafer/pad contact due to mechanical vibration, may result in a shift away from the hydroplaning mode even if the velocity and the normal pressure requirements are satisfied.
As a transition from the contact mode to the hydroplaning mode, the mixed mode will occur when the velocity is increased or the pressure reduced. hi this mixed regime shown in FIG. 1B, the velocity is neither high enough nor the pressure low enough to build up a thick fluid layer to support the normal load. This will result in some contact between the pad asperities and the wafer surface. The friction force is the weighted sum of the force necessary to deform the surface asperities at the wafer/pad and wafer/particle contacts, and that from the shear of the viscous slurry film. The friction coefficient in the mixed mode is generally in the range of about 0.01 and 0.1. The inventors have found that as the friction coefficient varies by one to two orders of magnitude among the different contact modes, the friction coefficient can be used as an indicator of the wafer/pad contact conditions.
The friction coefficient can be correlated to the Preston constant k p . It is indicated that k p decreases significantly in the hydroplaning mode, and is not satisfactory in the mixed mode due to the large variation of k p . Given this teaching, the present invention provides for carrying out the CMP process in the contact mode to increase the material removal rate at the surface of the wafer. The CMP process is carried out, and maintained substantially throughout, in the contact mode by operating at high k p regimes. In one embodiment, to carry out the CMP process in the contact mode, the method of the present invention provides for maximizing the product of the applied pressure and the relative velocity pv R . A range of pressures and velocities are suitable according to the present invention. In particular, the applied pressure p is in the range of about 14 to 70 kPa, and more preferably in the range of about 14 to 57 kPa. The relative velocity v R is in the range of about 0.05 to 4.0 m/s, and more preferably in the range of about 0.4 to 2.0 m/s.
To further understand the mechanism of the contact regime, we refer again to the Preston equation, Eq. (1). The material removal rate (OMRR) derived from experiments (the experiments are described indetail below), is plotted against the product pv R as shown in FIG. 2 . Literature data on Cu polishing (Stavreva et al., 1995 & 97; Luo et al., 1998) are also included in the plot and the corresponding conditions are shown below in Table 6 in the Experimental section. It must be emphasized, however, that the present data are obtained with a neutral slurry over a wide range of Pv R values, whereas the literature data represent chemical mechanical polishing but over a narrow range of p and v R . The mode of contact, however, should not depend on the chemistry of the slurry. Thus, if the mechanism of material removal is not affected by variation in p, v R , or pv R , the scatter in the data should be small and the slope of a line drawn through the data points is the Preston constant. The large scatter in the data clearly shows that the Preston constant is indeed not constant. FIG. 3 shows a plot of the Preston constant versus pv R for the present experimental data and those obtained from the literature. It is apparent that the data are widely scattered because the wafer/pad interface is not in contact for the majority of the pv R values.
Thus, to better delineate the effect of contact conditions, the normalized material removal rate, NMRR, and the Preston constant, k p , is plotted in FIGS. 4A and 4B against a dimensional parameter ηv R /p where η is the viscosity of the slurry. NMRR is the thickness of material removed per unit distance slide, or MRR/v R . It is apparent now that the NMRR and the Preston constant does not depend on the applied pressure and the velocity when ηv R /p is small. It is about 0.2×10 −6 MPa −1 at 14 kPa and 0.1×10 −6 MPa −1 at 48 kPa. The Preston “constant” stays high at low ηv R /p , i.e., in the contact mode, and drops down after the critical value, denoted as (ηv R /p ) c . The experimental results show that the transition occurs around the same (ηv R /p ) c for both pressures. This implies that the Preston constant is independent of pressure and velocity when the wafer/pad interface is in the contact mode. After the transition point, the Preston constant decreases as v r is increased or p decreased. It is also apparent from that the Preston constant shows the same trend as that of friction coefficient (shown in FIG. 5 ), and the transition in k p occurs at about the same values of ηv R /p . In the transition regime, the Preston constant is not independent of pressure and velocity. It is found that k p varies as (ηv R /p ) −1 at 14 kPa and as (ηv R /p ) −0.5 at 48 kPa in the mixed regime.
The variation of k p can be explained in terms of the shifting interfacial conditions as follows. In the mixed mode, the friction coefficient decreases with ηv R /p which implies that the wafer/pad contact area also decreases with ηv R /p . The lack of contact further reduces the material removal rate since the fluid shear and the motion of the loose particles in the discontinuous fluid film cannot apply sufficient pressure on the wafer surface and remove material. With increasing ηv R /p , particle rolling will increase and particle translation will decrease. In fact, some researchers tried to fit their data numerically to account for the variation of Preston “constant” at low pressure or high velocity conditions by a polynomial function of the Pv R product (Zhao and Shi, 1999), or introduce extra pressure and/or velocity terms in Preston equation (Luo et al., 1998). They proposed that the interfacial shear stress and particle velocity will enhance the chemical reaction rate or mass transfer from the wafer surface. However, the variation in k p might just be due to the varying interfacial contact modes as FIG. 4A shows, and thus each contact mode is expected to have a different Preston constant.
A cross plot of the Preston constant versus friction coefficient is shown in FIG. 6 . Before the transition point, i.e., at the beginning of the mixed mode, the Preston constant and friction coefficient are positively correlated; the correlation coefficient is almost 1. However, the Preston constant shows less correlation with friction coefficient with an increase of ηv R /p in the mixed mode. FIG. 4B further emphasizes the variation in the material removal rates with different contact modes. Thus, contrary to the prior art and the conventional teachings, the Preston constant is not truly constant over the different contact regimes.
Of particular advantage, the method of the present invention employs the effects of the parameter ηv R /p on the friction coefficient and the Preston constant to promote increased material removal in the CMP process. For a certain slurry viscosity, the different wafer/pad contact regimes are delineated in the v R −p space as shown in FIG. 7 . Corresponding to the point (ηv R /p ) c for transition from the contact mode to the mixed mode (see FIG. 5 ), a line L 1 with the slope (ηv R /p ) c is drawn in FIG. 7 to represent the transition points for different pressures and velocities. The region bounded by L 1 and the p-axis represents the contact mode. Similarly, another line, L 2 , with a greater slope to represent the transition from the mixed mode to the hydroplaning mode is drawn. The region bounded by L 2 and the v R -axis represents the hydroplaning mode. The region bounded by L 1 and L 2 represents the mixed mode. According to the present invention, the CMP process is carried out in the contact mode, i.e. the region bounded by L 1 and the p-axis in FIG. 7 . In particular, the method of the present invention provides for carrying out the CMP process according to the following equation:
v R /p ≈C 1 /η(1)
where v R is the relative velocity of the polishing pad and the wafer, p is the pressure applied to the wafer, and C 1 is a constant that is related to the geometry of the polishing interface and machine design, and η is the viscosity of the slurry used in the particular CMP process. In one example of the present invention, C 1 , is in the range of about: 1×10 -31 7 to 1×10 −6 meters.
In the preferred embodiment, in addition to increasing the MRR, the present invention provides for reducing the within-wafer non-uniformity (WIWNU). The WIWNU is the degree of non uniformity of the layers of material across the surface of the wafer. Referring again to Eq. (1), the pv R product should be as high as possible to increase the MRR, i.e., the highest velocity available is preferable in the contact regime for a given pressure, and vice versa. This suggests that the preferred processing conditions are located on the line L 1 . However, a high pressure requires a sturdy machine structure, which generally sets an upper limit for the applicable pressure. Further, at a high pressure even a small vibration of the machine might result in large fluctuations on the normal load and friction force at the wafer/pad contact interface, and thus increase the WIWNU. These considerations suggest that the pressure increase cannot be unlimited. Similarly, extremely high velocities are not desirable because it is difficult to retain the fluid slurry on the platen at high velocities.
The inventors have discovered that an even a more important consideration for the process parameters of pressure and velocity is that of heat generation. The rate of thermal energy generation due to friction, P, can be expressed as
P=μπr w 2 pv R (2)
Thus, the higher the value of the product pv R is, the greater the amount of heat generation. Based on experiments conducted by the inventors, the typical value of heat generation rate for a 100 mm diameter Cu wafer polished at 48 kPa normal pressure and a velocity of 0.5 m/s and is about 80 W. The frictional heat generation will raise temperature and vary the chemical reaction rates locally, and thus deteriorates the polishing uniformity. In the contact mode, the heat generated is not efficiently removed by the slurry transport since the volume flow rate through the interface is rather low. Even with external cooling of the pad and the wafer carrier, the heat removal rate can be limited due to the low thermal conductivities of the silicon wafer and the polishing pad which is typically made from polyurethane. To address this issue of heat generation, one embodiment of the present invention provides for establishing an upper limit for the applicable pv R product. This upper limit for heat generation is set as pv R =C 2 , where C 2 is a constant that depends the interfacial friction coefficient and the thermal conductivity of the backing film and the pad, and the cooling system of the head and the platen. The constraint pv R =C 2 is shown as a rectangular hyperbola in FIG. 7 .
A preferred process condition (p*, v R *) may be defined by the intersection of pv R =C 2 * with L 1 . Operation of the CMP process in the mixed and hydrodynamic modes is not optimum for reasons cited earlier. It should be understood that the constant C 2 is not fixed, and that appropriate external cooling may be installed in the polishing head and the platen to improve the efficiency of heat removal and increase the constant C 2 , and thus the exact preferred process conditions will change based on changes in the value of C 2 . As C 2 * is increased with additional cooling means such as external cooling, a higher MRR can be achieved by increasing the P*v R * product. Further, for other practical reasons (such as mechanical vibration, slurry retainment, and the like.), the actual most preferred pressure and velocity values can be somewhat different from p* and v R *; however, such actual most preferred values can be determined with routine experimentation based on the teaching of the present invention. For example, using friction force measurements during the CMP process and applying Eq. (2), one can characterize the contact regime, and then identify the transition point from contact mode to mixed mode, and determine the most preferred pressures and velocities for the particular CMP machine.
Thus, in another embodiment of the present invention, a method of chemical mechanical polishing is carried out such that the following equation is satisfied:
v R P≦C 2 (3)
where v R and p are as defined above and C 2 is dependent on the interfacial friction coefficient and the thermal conductivity of the backing film and the pad, and the cooling system of the head and platen. As described above C 2 is an upper limit which constrains the applied pressure and relative velocity parameters due to heat generation. Preferably this upper limit C 2 is selected such that the temperature rise from the heat generated from the products of v R p, does not exceed about 10 degrees K (or ° C.) , and more preferably does not exceed about 5 degrees K.
The constant C 2 is dependent on the CMP machine configuration, and this will vary for each tool. The machine configuration variables which effect C 2 are related to heat generation and are primarily the interfacial friction coefficient, the thermal conductivities of the pad and its backing film, and the cooling system (i.e. the thermal properties) of the wafer carrier head and the platen.
One example of how C 2 is determined is provided below. It is important to note as mentioned above that C 2 will vary depending on each specific CMP tool configuration and is thus in no way limited by the following example, and C 2 can be determined based on the teaching herein.
It is assumed that a portion of the frictional heat, αQ, is transferred into the pad, where α is the fraction (0<α<1) and Q is the total energy generated (Q=P·t , where t is the total CMP process time). Additionally, the pad is assumed to be adiabatic, i.e. all heat transferred into the pad will be stored in the pad and increases the temperature without dissipating into environment. This is a “worse case” estimation. It can be further assumed that the temperature raise, ΔT, is uniform in the pad and is given by
α Q=mCΔT (4)
where m is the mass of the pad, and C is the specific heat of the pad.
Combined with Eq. (2), the constant C 2 in Eq (3) to define the maximum pv R product in one example can be determined as: C 2 = m C Δ T a μπ r w 2 t ( 5 )
where are terms are as defined above. The value of the factor a between 0 and 1, must be determined by experimental measurement. During the CMP process, most of the heat is transferred into the slurry and α is small. For instance, in one example if we assume that a 0.1, m=0.1 kg for 300 mm (12″) pad, C=2100 J/kg·K, ΔT is less than 5 K (or ° C.), and t=2 min; then the value of C 2 , which is the maximum pv R product, is about 27 W/m 2 .
Thus, in summary, C 1 is used to determine the maximum kp and v R /p ratio which provides for carrying out the process in the contact regime, and C 2 provides an upper limit on the product of v R p to limit the amount of adverse heat generation. By doing so our goal is to increase the material removal rate and also to promote maintaining the WIWNU at a desired low level.
In another aspect of the present invention, the friction coefficient is measured and monitored to maintain the CMP process in the contact mode. As described above, the friction coefficient varies by one or two orders magnitudes among the different contact modes. Generally, the friction coefficient for contact mode will be in the range of about 0.1 or greater; for the mixed mode in the range of about 0.01 to 0.1, and for the hydrodynamic mode in the range of about 0.001 to 0.01. According to the present invention, this wide range in friction may be employed to monitor the contact conditions at the wafer/pad interface during the CMP process. In particular, friction in the system may be measured directly by sensing the load in the system and/or the torque. Torque sensors may be installed to measure the torque on the motor that rotates the wafer carrier head. Alternatively, or additionally, torque sensors may be installed to measure the torque on the motor that rotates the platen. Further, load sensors may be installed, preferably on the wafer carrier, to measure the load in the system. Preferably, the load sensors are installed to measure the frictional forces in two orthogonal directions on the plane in parallel with the pad surface. Measurements from these sensors are then processed to provide the friction coefficient using conventional means. To maintain the process in the contact mode, a controller may be used which adjusts the relative velocity and/or applied pressure responsive to the torque and load sensor measurements.
Experimental
The following experiments have been conducted. These experiments are provided for purposed of illustration, and are in no way intended to limit the invention in any way. Experiments on Cu blanket wafers with neutral Al 2 O 3 slurry have been conducted to verify the models for a wide range of pressure and velocity settings.
A rotary-type polisher, as well known in the art, was employed in the polishing experiments. The stainless steel wafer carrier was connected to a head motor by a gimbaling mechanism to align the wafer parallel to the platen surface. Two load sensors and a torque sensor were installed to measure the frictional forces in two orthogonal directions and the torque of the head motor. The capacities of the load and the torque sensors are 222 N and 5.65 N·m, and the resolutions are 0.067 N and 0.001 N·m, respectively. The head unit was driven by pneumatic pistons for vertical motion and for applying normal pressure. The platen unit is composed of a detachable 300 mm dia. aluminum platen and a platen motor. Surfaces of the aluminum platen and the base were ground to achieve a high degree of flatness and surface finish. The polisher was computer controlled so that the applied load, rotational speeds of the wafer carrier and of the platen could be controlled independently, and the forces and torques on the wafer could be acquired in real time. The entire apparatus was housed inside a laminar flow module equipped with HEPA filters to ensure a contaminant-free environment.
Silicon wafer substrates, 100 mm in diameter, coated with 20 nm TiN as adhesion layer and 1 μm PVD Cu on the top were used as test wafers. The density and hardness of the coating materials are listed in Table 1. A neutral slurry (pH =7) with Al 2 O 3 abrasive particles was used. The viscosity of the slurry was about 0.03 Pa. Additional properties are shown below in Table 2.
TABLE 1
Density and Hardness of Experimental Materials
Material
Density (kg/m3)
Hardness (MPa)
Cu
8,920
1,220 ± 50
TiN
5,430
17,640 ± 1,235
Si
2,420
8,776 ± 570
TABLE 2
Properties of the Slurry
Abrasive
α-Al 2 O 3
Particle Size (μm)
0.3
Particle Hardness (Mpa)
20,500
Concentration (vol. %)
2-3
Viscosity (Pa s)
0.03
pH
7
A commercial composite pad (Rodel IC1400) was employed in the polishing experiments. The pad comprised a micro porous polyurethane top layer (Rodel IC1000) and a high-density urethane foam as underlayer. The room temperature elastic moduli of the top pad and the composite pad were about 500 MPa and 60 MPa, respectively. Further details of the pad are listed in Table 3.
TABLE 3
Pad Properties
Pad
Rodel IC1400 (k-grooving)
Material
Polyurethane
Thickness (mm)
2.61 (1.27*)
Density (kg/m3)
750*
Hardness
57 shore D*
Pore Size (μm)
20-60 (isolated)*
Groove Pattern
250 μm wide, 375 μm deep with a 1.5 mm
pitch, concentric
*Top pad (IC1000)
Table 4 lists the experimental conditions employed in this study:
TABLE 4
Experimental Conditions
Normal Load (N)
108,379
Normal Pressure (kPa)
14, 48
Angular Speed (rpm)
5-420
Linear Velocity (m/s)
0.05-3.91
Slurry Flow Rate (ml/min)
150-250
Duration (min)
2
Sliding Distance (m)
6-469
Ambient Temperature (° C.)
22
Relative Humidity (%)
35-45
Each wafer was weighed before and after polishing to calculate the average material removal rate (MRR). The worn pad surface and Cu-coated wafer surfaces were observed in a scanning electron microscope (SEM) to characterize the post-CUT pad topography and surface scratches on wafers.
The effects of process parameters on the material removal rate, and the, relations between the friction coefficient and Preston constant are examined. The results show that Preston constant is independent of the pressure and velocity only in the contact regime. Moreover, the high correlation between the friction coefficient and Preston constant in the contact mode allows the use of monitoring the friction coefficient in-situ to monitor the removal rate during the CMP process. As illustrated, the MRR is increased when operating in the contact mode as provided by the present invention.
The foregoing description of specific embodiments and examples of the invention have been presented for the purpose of illustration and description, and although the invention has been illustrated by certain of the preceding examples, it is not to be construed as being limited thereby. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications, embodiments, and variations are possible in light of the above teaching. It is intended that the scope of the invention encompass the generic area as herein disclosed, and by the claims appended hereto and their equivalents.
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In the Chemical Mechanical Polishing (CMP) process employed for microelectronics manufacturing, three contact regimes between the wafer surface and the polishing pad may be proposed: direct contact, mixed or partial contact, and hydroplaning. However, an effective in situ method for characterizing the wafer/pad contact and a systematic way of relating contact conditions to the process parameters are still lacking. In this work, the interfacial friction force, measured by a load sensor on the wafer carrier, has been employed to characterize the contact conditions. Models that relate the friction coefficient to the applied pressure, relative velocity, and slurry viscosity are developed and verified by experiments. Additionally, a correlation between friction coefficient and the material removal rate (MR) is established and the effects of process parameters on the Preston constant are investigated.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to manufacturing of polyester based expanded materials made of pre-cleaned and compounded post-consumer polyester by increasing the intrinsic viscosity (IV) during an extrusion process, the manufacturing of such materials and the use of products made thereof.
[0003] 2. Description of the Background Art
[0004] The term “post consumer” is defined as material being brought back into the process—i.e. being recycled—after its prior use, e.g. as PET bottles.
[0005] Expanded polyester polymers, i.e. polyester foam or sponge, are of major importance for a large number of applications related to insulation against temperature gradients, noise shielding, vibration damping, lightweight construction etc. Foaming of polyesters and the use of post-consumer polyester are rather new technologies, and only limited numbers of prior art can be found.
[0006] M&G Polimeri describes (EP 0866089) that significantly higher than standard intrinsic viscosity (IV) resin (IV>1.2 ml/g) is required for physical foaming of polyester, especially when lower densities are targeted. A high viscosity is required in order to build up necessary pressure for foaming to occur and to prevent cell collapse.
[0007] Traditionally solid state polymerization is used to increase the molecular weight and hence viscosity to the required level.
[0008] The re-use of post consumer polyester material is not novel. For example molded solid and high density sheets have been made by using post consumer raw materials.
[0009] CH686082 and JP2000169613 describe the manufacturing of such products, but limited to molded products due to the low intrinsic viscosity of post consumer polyesters achievable during such processes.
[0010] Furthermore blends of post consumer polyester material, polypropylene and fillers have been used to make this polyester foamable (see JP2001129867), but the possible quantity of post consumer polyester is very limited.
[0011] JP2003165861 describes the expansion of polyester resins using post consumer material but limited to the use of chemical blowing agents under the additional term of using a thickening agent <=20 g/10 min in melt flow rate (MFR) to increase the intrinsic viscosity to the required level.
[0012] All these processes do not allow the use of high amounts of post-consumer polyester and/or lead to worse mechanical properties compared to virgin polyester materials.
[0013] Some work was even done to improve the intrinsic viscosity of post consumer polyester by solid state polymerization, e.g. U.S. Pat. No. 6,130,261 describes the recycling of polyester foam by densification and afterwards drying the material, but the process takes several hours, limited to expanded polyester as base materials.
[0014] It is widely known that extrusion reduces the intrinsic viscosity by mechanical and thermal degradation of polyesters which is detrimental for foaming. That makes it quite difficult to use post-consumer polyester, especially for foaming processes which require high intrinsic viscosities.
SUMMARY OF THE INVENTION
[0015] In accordance with one embodiment of the present invention, an expanded, cellular material comprising at least 50 wt % of post-consumer polyester resin whereby the intrinsic viscosity of the polymer(s) is upgraded during the foam extrusion process and the intrinsic viscosity of the exiting foam is characterized being higher than 1.2 ml/g, preferably above 1.35 ml/g and the density is between 40 and 200 kg/m 3 , preferably between 50 and 150 kg/m 3 .
DETAILED DESCRIPTION OF THE INVENTION
[0016] It has now unexpectedly found out that an additional extrusion step of post-consumer polyester prior to the foam extrusion process results in superior foams, equal to foams made of virgin polyester.
[0017] In order to achieve this, post consumer polyester has to be pre-cleaned from dust and moisture and afterwards compounded and filtered in an extruder. During this step moisture and oxygen can be exhausted by melt degassing to prevent the material of further oxidative and hydrolytic degradation. Additionally chain extending additives can be added to increase the intrinsic viscosity. Afterwards the material is granulated.
[0018] During the subsequent foam extrusion chain extending additives need to be added to raise the intrinsic viscosity to a level above 1.2 ml/g. Further additives, e.g. nucleating agents, fillers, flame retardants etc. can be added to adjust the properties of the foam.
[0019] This invention focused on foaming a resin or a blend of resins, where most of the polymer consisted of post consumer material, such as washed PET bottle flakes. Different types of post consumer sources were evaluated and used in different levels. During this work a reactive additive (RA) that increases the viscosity by chain extension and side chain branching during extrusion (described as chain extending concentrate in European patent application 09 006 678.8) has been used. The chemistry of this package is described in more detail in the said patent application.
[0020] In all below trials, a modified twin-screw extruder from Berstorff was used. The extruder was equipped with special screws made for PET foaming, having compressive ratio larger than 2.0, and L/D larger than 28. Furthermore reversed elements need to be used in order to prevent gas escape backwards from injection area. In addition, the feeding pipe used in dosing station was equipped with vibrating device where the vibration frequency could be controlled. This enabled consistent feeding of amorphous post-consumer polyester bottle flakes, and prevented bridging of the material.
[0021] Physical blowing agent was injected after the melting zone under high pressure, and consequently the melt was mixed by means of screw elements and static mixer. The level of blowing agent was adjusted to achieve the target density. The mixture of blowing agent and polymer was cooled during extrusion close to crystallization point and sufficient pressure was maintained by controlling the viscosity of the resin and the temperature of the mixture.
[0022] The reactive additive (RA) was used in different levels to adjust the viscosity and pressure to a sufficient level (typically min. 60 bars measured in the extruder head). As the mixture exited the extruder, the rapid pressure drop caused rapid foaming of the polymer, whereby the cell size was controlled by level of special nucleating agent: Nucleating agent could be an inorganic material, in this case a talc containing masterbatch, organic material or gaseous material. Furthermore a flame retardant additive, such as phosphate, halogen, borate, melamine or similar containing component may be used for applications where fire retardancy is required. The foam was then cooled down and later analyzed in the laboratory. All raw materials were dried to contain moisture below 100 ppm prior to feeding into the extruder.
[0023] In this invention post consumer flakes that have significantly lower starting IV have been used, where by means of reactive foam extrusion the IV of the polymer is increased in a single step to a satisfactory level while at the same time a physical blowing agent is introduced to the mixture. As the mixture exits the extruder, the IV has reached level superior to 1.2 ml/g, and consequently by sudden pressure drop the physical blowing agent rapidly expands and foaming takes place.
Comparative Example 1
[0024] Commercially available PET resin from Sabic (BC-112) was fed into the extruder with throughput of 400 kg/hr together with the previously mentioned reactive additive (RA) and a nucleating agent (NA). Physical blowing agent was adjusted to a level that would result in final product having density of 100 kg/m 3 . At an RA level of 3.4 wt % and NA level of 2.5 wt % very nice foam with homogeneous cell structure and uniform rectangular shape was obtained. The virgin PET resin was characterized of having an average MFR of 38.3 g/10 min at 260° C. using 2.16 kg weight (die with L=8 mm and D=2.095 mm).
Comparative Example 2
[0025] The comparative example 1 was repeated, but replacing BC-112 material with post consumer flakes from RE-PET. The polymer was fed into the in the extruder with throughput of 400 kg/hr together with the reactive additive (RA) and the nucleating agent (NA). Physical blowing agent was adjusted to a level that would result in final product having density of 100 kg/m 3 . The process was found very unstable, mostly due to dosing problems and huge variations in reactivity of the additive (RA was used in level of 6.5% and NA at level of 2.5%). Foam was obtained, but visually it did not look good, containing some collapsed areas, and in average larger cells than from example 1. Furthermore the shape was not rectangular, but collapsed from the middle. Additionally it was noticed that the extruder die was partially blocked after a short time due to impurities present in the post consumer flakes, which partially caused the uneven cellular structure.
Comparative Example 3
[0026] Granulated post-consumer PET material from PTP (PET-M) was fed into the extruder with throughput of 400 kg/hr together with the reactive additive (RA) and the nucleating agent (NA). Physical blowing agent was adjusted to a level that would result in final product having density of 100 kg/m 3 . The RA level was kept the same as in comparative example 2 (6.5 wt %). Poor looking foam, with significant cell collapse and rough surface characteristic was obtained and pressures were low in the extruder.
Comparative Example 4
[0027] Comparative example 3 was repeated but with RA level of 8.0 wt %. The pressure in the extruder remained low and only an unsatisfactory foam quality was obtained (slightly improved from example 3).
Innovative Example 1
[0028] The recipe from Example 3 was used, but 15 wt % of PET-M was replaced by virgin resin BC-112. Immediately the viscosity increased to sufficient level and good looking foam with uniform cell structure and rectangular shape was obtained by using RA at the level of 6.5 wt %. The process was found quite stable.
Innovative Example 2
[0029] Post consumer flakes from RE-PET were compounded and filtered at an external compounding company as received using an twin-screw extruder at 300 rpm. The granulated material had an average MFR of 261 g/10 min at 260° C. using 2.16 kg weight.
Innovative Example 3
[0030] Post consumer flakes from RE-PET were compounded and filtered at an external compounding company using a twin-screw extruder which was equipped with vacuum port and screw speed was set at 150 rpm. Also the material was pre-cleaned from dust and moisture prior to compounding. The granulated material had an average MFR of 33.3 g/10 min at 260° C. using 2.16 kg weight.
Innovative Example 4
[0031] Post consumer flakes from RE-PET were compounded and filtered at an external compounding company using a twin-screw extruder with vacuum port and a screw speed of 150 rpm (as in innovative example 3). In addition a relatively low level of reactive additive (RA=1.5 wt %) was compounded with the flakes. The granulated material had an average MFR of 14.3 g/10 min at 260° C. using 2.16 kg weight.
Innovative Example 5
[0032] The granulated raw material according to innovative example 2 was fed into the extruder with throughput of 400 kg/hr together with the reactive additive (RA) and the nucleating agent (NA). Physical blowing agent was adjusted to a level that would result in final product having density of 100 kg/m 3 . RA was adjusted to level of 8.0 wt %, the NA at level of 2.5 wt % and the process was found unstable with high pressure variations and poor looking foam was obtained. The foam was characterized having larger than usual average cell size and a rough surface, which can be linked to pre-foaming of the material.
Innovative Example 6
[0033] The granulated raw material according to innovative example 3 was fed into the extruder with throughput of 400 kg/hr together with the reactive additive (RA) and the nucleating agent (NA). Physical blowing agent was adjusted to a level that would result in final product having density of 100 kg/m 3 . RA was adjusted to level of 6.5 wt %, the NA at level of 2.5 wt % and very nice looking foam was obtained, characterized by uniform cell structure and an almost rectangular shape. The process was found quite stable under these conditions, with some variations in pressure.
Innovative Example 7
[0034] The granulated raw material according to innovative example 4 was fed into the extruder with throughput of 400 kg/hr together with RA and the nucleating agent (NA). Physical blowing agent was adjusted to a level that would result in final product having density of 100 kg/m 3 . At RA level of 5.5 wt % the extrusion process was found very stable and the foam looked identical to the foam obtained from Comparative example 1.
Innovative Example 8
[0035] A foam according to Innovative example 7 was manufactured, where additionally two different flame retardants were mixed with the recipe, more specifically 5 wt % of Exolit 950 and 1 wt % of Mastertek 372815 were used. Furthermore the blowing agent was adjusted to a higher level so that a density of 70 kg/m 3 (±5%) was achieved. The foam looked very good, having slightly larger cells than obtained in Innovative example 7, and the process was found stable. The foam was characterized of having B2 classification according to DIN 4102 and E-class according to ISO 11925.
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Manufacturing of polyester based expanded materials made mostly of pre-cleaned and compounded post-consumer polyester by increasing the intrinsic viscosity (IV) during an extrusion process is described. By careful selection of processing conditions and parameters, it is possible to obtain low density polyester foam material with good cellular structure and under stable processing conditions.
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BACKGROUND OF THE INVENTION
The present invention relates to an antilocking control system for the wheel brakes of a vehicle. More particularly the present invention relates to such an antilocking control system which includes two identically designed control units each having at least one wheel speed sensor, an evaluation circuit and a brake pressure control unit, for different wheels of the vehicle, as well as a device for testing the operability of the antilocking control system at certain desired time intervals.
A device for checking an antilocking control system for the wheel brakes of a vehicle is known, for example, from German Offenlegungsschrift (Laid Open Patent Application) No. 2,323,358, corresponding to U.S. Pat. No. 3,907,380 issued Sept. 23rd, 1975, to Helmut Fleischer et al. According to the teaching of that patent, a signal corresponding to a given wheel velocity curve is applied to a test input of the control system when, for example, the vehicle is started, and a determination is made whether certain events will occur at given time intervals in view of this known test signal.
SUMMARY OF THE INVENTION
It is the object of the present invention to simplify, the testing of the proper operation of an antilocking control system which includes two identical antilocking control units.
This is accomplished according to the present invention in that in an antilocking control system for the wheel brakes of a vehicle including two identically designed control units and a testing means for testing the operability of the control system; the testing means includes switching means, responsive to a start instruction for simultaneously feeding at least one identical test signal to each of the two control units, and interrogation and testing means for comparing the effect of the test signal on the two control units by comparing output signals at given corresponding locations in the two control units for coincidence with respect to the timely occurrence and/or magnitude of the signals and for emitting a control signal, e.g. to switch-off the antilock control system and/or actuate a warning device if any deviation between the two signals being compared exceeds a given value.
The present invention is based on the assumption that there is a great probability that the same error will not occur simultaneously in both units between two testing moments which lie relatively closely together in time.
The present invention eliminates the provision of testing means to determine, upon receipt of a test signal, whether certain events will occur at certain points in time. In contradistinction thereto, in the present invention it is only necessary to determine whether changes in the signal occur at the same moment in both control units at corresponding locations. This type of test can be effected much more easily.
If the antilocking control system employs threshold circuits in both units for the wheel deceleration, the wheel acceleration and/or the wheel slip, the test signal fed to both units is dimensioned so that output signals will appear at the outputs of the individual threshold circuits of each control unit in succession. In this case the sensing and testing means are connected with the desired outputs of the signal generators and the coincidence of the occurrence of corresponding signals can be monitored. The simultaneous occurrence of control signals for corresponding valves of the pressure control device can also be monitored in this way.
In order to generate the above-mentioned signals, the test signal fed to the two control units is provided with at least one section or portion which corresponds to a constant wheel velocity, at least one section or portion which corresponds to a drop in wheel velocity, and at least one section or portion which corresponds to an increase in wheel velocity.
According to a particularly preferred embodiment of the present invention, the signals from the control units to be controlled, which signals have been generated in different signal lines, are linked by means of a logic circuit so that a signal sequence of logic O and L signals is produced. The linkage must be selected so that the signal sequence is characteristic for the creation and/or disappearance of the signals to be tested in the various lines. For this purpose it is only necessary to compare the signal sequences generated by the two control units.
When at least one inlet valve and one outlet valve are controlled and if components are available for generating a signal when a given wheel deceleration and wheel slip are exceeded per control unit, the two valves can be linked together via an EXCLUSIVE-OR gate, the deceleration signal and the slip signal can be linked by means of an AND gate and the output signals from these two gates can be linked by means of an EXCLUSIVE-OR gate.
If a monitoring circuit is additionally used in the anti-locking control system so that the control system is switched off if circuit members respond for too long a period of time, switching means may additionally be provided which generate signals for triggering the time members provided for the monitoring. The testing means here monitor the occurrence of signals at the end of the time constants. Here, too, it may be tested whether corresponding signals are present simultaneously if the two control units have separate monitoring circuits. If the time members are of the digital type, e.g., counters, they are charged with or fed a sequence of actuating pulses at a much higher frequency than that which occurs during the regulating process so that the testing operation can be accelerated.
In the case where two wheels, e.g., a front wheel and a rear wheel, have their brake pressure regulated by each one of the two control units and where a signal identifying the behavior of the wheel is derived from both wheels and processed into control signals for the associated wheel, the expenditures for the testing operation can be reduced in that a signal is produced in both control units from corresponding signals, e.g., from the two deceleration signals, in that the signals are alternatingly scanned at a rapid rhythm and the scanned signals are combined. Since this again occurs identically in both control units, it is still possible to compare the corresponding signals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block circuit diagram of one embodiment of an antilocking control system with a testing arrangement according to the invention.
FIG. 2 is a time diagram to explain the circuit of FIG. 1.
FIG. 3 is a block circuit diagram showing a modification of the embodiment of the invention shown in FIG. 1 whereby the invention can be utilized with antilock control systems having two sensors per control unit.
FIG. 4 shows the block 30 of FIG. 1 in more detail including also the connections to and from blocks 6 and 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1 there is shown an antilocking control system for a vehicle which includes two substantially identically designed control units each comprising a wheel speed sensor 10 or 20, respectively, a transducer 11 or 21, respectively, a signal evaluation control circuit including a signal processing unit 12 or 22, respectively, and a control logic unit 13 or 23, respectively, and a pressure control unit including an inlet valve 14 or 24, respectively, and an outlet valve 15 or 25, respectively. In the described embodiment, it is assumed that the units are of digital design, i.e., a digital signal corresponding to the speed of the wheel, as sensed by the sensor 10 or 20, is generated in transducer 11 or 21, respectively and is fed to signal processing unit 12 or 22, respectively. In the signal processing units 12 and 22 signals are generated on respective output lines whenever a certain wheel deceleration threshold value -b, certain wheel acceleration threshold values +b 1 and +b 2 , and different slip threshold values +λ 1 and λ 2 are exceeded. These generated signals are fed to the logic circuits 13 and 23, respectively, wherein they are processed into actuating signals for valves 14, 15 or 24, 25, respectively. Such vehicle wheel antilock systems are well known in the art, for example from U.S. Pat. No. 3,754,797 issued Aug. 28th, 1973 to Rodi et al. taken in combination with U.S. Pat. No. 3,976,860 issued Aug. 24, l976 to Gerstenmeier et al.
To test the system, a signal generator 30 is provided which at desired times for example, in response to a signal from the ignition switch at every start of the vehicle feeds a test signal to both transducers 11 and 21. It must be assured in this connection that the corresponding groups of the two control units 10-15 and 20-25 have the same starting position. The test signal produced by generator 30 is dimensioned so that signals corresponding to all functions to be tested are generated one after the other so that it can be determined whether corresponding signals are generated simultaneously in the two control units.
In the embodiment of FIG. 1 it is assumed that at the beginning of the test procedure the digital memory in each of the processing units 12 or 22 which stores the wheel velocity is set to a position corresponding to a high wheel velocity v 1 but that the reference value required for the slip formation is set to 0, and that transducers 11 and 21 are initially fed a test signal with a frequency which corresponds to a speed v 2 which is slower than v 1 . Since the signals processed in the transducers and in the signal processor, which signals correspond to the speed of the wheel V R and to the reference speed V Ref , are generated through a filter (this means that these values can adapt themselves to the momentary wheel speed only within given steps), signal sequences are produced (the digital pattern is not shown) which correspond to the sequence of the wheel speed V R or the reference speed V Ref shown in the left portion of FIG. 2 up to about 300 msec. The sequences shown in FIG. 2 apply to both control units in the same way.
Due to the shape of the curve for the wheel speed V R , a deceleration signal (-b signal) is produced until the speed V R has been adapted to the speed V 2 given by the input signal, i.e., at moment t 1 , as shown in the corresponding line of FIG. 2. This signal causes the inlet valve 14 or 24 in the pressure controller to respond (see line EV). However, as shown in line EV at time t 2 the control signal for the inlet valve 14 or 24 drops, and the valve is closed, since for safety reasons the controller will not permit a response of the inlet valve 14 or 24 which is longer than the time period T 1 = (t 2 - t 1 ).
At time t 3 the frequency of the input test signal is changed so that it corresponds to the wheel speed 0. This causes the filtered wheel speed V R to drop at a given rate. After a time Δ t after time t 3 , which corresponds to a certain reduction in speed, a deceleration signal -b is again produced which causes inlet valve 14 or 24, respectively, to respond (line EV). At time t 4 the first slip threshold λ 1 has been exceeded and a corresponding signal (λ 1 - line) is produced which causes outlet valve 15 or 25 (line AV) to respond. A short time later at time t 5 the second slip threshold λ 2 is also exceeded and a λ 2 slip signal is generated. At time t 6 the wheel speed has adapted itself to the starting value where it remains constant until at time t 7 the frequency of the input test signal is again advanced to correspond to a speed V 2 so that V R increases and tries to adapt itself to the value V Ref of the speed V R . Together with the rise in speed at +b 1 acceleration signal is generated followed with some delay by a +b 2 acceleration signal. The +b 1 signal produces the end of the pressure reduction stage by closing the outlet valve 15 or 25 (line AV) and the +b 2 signal causes the inlet valve (14 or 24, respectively) to open for a time duration T 2 (line EV).
According to the present invention, the signals from both control units to be monitored are tested for simultaneous occurrence. This is done so that a pulse sequence is generated which characterizes these signals and then the two resulting pulse sequences are compared with one another. These pulse sequences are generated in the logic networks 16 or 26, respectively, in which the signals -b, λ 2 , EV and AV are linked according to the following equation:
TM = [EV ⊕ AV] ⊕ (-b) · (λ.sub.2)
In network 26 the gates required for this purpose are shown, i.e., an Exclusive-OR gate 1 having its two inputs connected to receive the EV and AV signals and its output connected to one input of an Exclusive-OR gate 2 whose other input is connected to the output of an AND gate 3, which links the -b and λ 2 signals. At the output of Exclusive-OR gate 2 there appears the signal sequence shown in line TM of FIG. 2. This signal sequence and the corresponding sequence from member 16 are fed to comparator 4 which compares same and switches relay 5 if deviations occur between the signal sequences TM being compared. Relay 5, when switched, and by means of circuitry (not shown) controlled thereby, causes the antilocking control system to be switched off and/or a warning indication to be produced, preferably by allowing a warning indication turned on at the beginning of the test to remain on.
If the antilocking control system is provided, in a manner well known in the art, with a monitoring or safety circuit to prevent the pressure control valves, e.g., 14 and 15, from responding for too long a period of time, it may also be necessary to test this monitoring or safety circuit of the controller in that the response of the timing members of this safety circuit are monitored. In the safety circuit, the timing members emit a signal if, for example, a valve has been actuated longer than the time constant of the time members. In the embodiment of FIG. 1 it is assumed that the test of this safety or monitoring circuit is to take place before the other operational test described above and accordingly the signal generator 30 initially produces a test signal for this purpose. Preferably the frequency of this test signal is substantially higher than the frequencies generated during normal operation of the system. In the embodiment of FIG. 1, the timing members of the safety or monitoring circuit for the control unit 20-24 are assumed to be included in block 6 which receives its actuating signal from signal generator 30. At the same time, the test signal from signal generator 30 is fed to the testing time members 8 in block 7 to trigger same. The outputs from the timing members in block 6 and the timing members 8 are compared in a comparator 9 and if approximate coincidence of the time members is noted, a signal is fed to signal generator 30 to cause same to initiate the operational test for the control units 10-15 and 20-25. Alternatively, if separate safety or monitoring circuits are provided for each of the two control units, the outputs of the corresponding time members for each of the two control units can be compared.
In the embodiment of FIG. 1, each control unit is responsive to the rotational behavior of only one wheel of the vehicle, i.e., only one sensor, and controls the brake pressure at only the associated wheel brake. Often however, the control units or units of an antilock control system are responsive to the rotational behavior of a pair of wheels, e.g., a front wheel and a rear wheel, and processes these signals to provide control signals for the pressure control valves associated with these two wheels. FIG. 3 shows only one such control unit of an antilock control system. The control of the brake pressure of at least two wheel brakes dependent of the signals of at least two sensors is known for example from U.S. Pat. No. 3,909,077 issued Sept. 30th, 1975 to Leiber et al. and British Pat. No. 1,378,347. Here only one brake pressure control means is provided.
In FIG. 3, blocks 10' to 15' of the control unit correspond for example, to blocks 10-15 of FIG. 1. Since this control unit must also regulate the brake pressure of a second wheel brake, a second control channel for the control unit, including an additional sensor 40 for measuring the rotational behavior of the second wheel, transducer 41, signal processor 42, and additionally inlet valve 44, and outlet valve 45 is provided. The manner in which an output signal, which can be compared with a corresponding output signal from a further such control unit in the manner described with regard to FIG. 1, can be generated from the corresponding signals of the two control channels of the control unit is shown in an example of the deceleration signals -b v and -b h for the two wheels associated with the sensors 10' and 40. As shown the two deceleration signals -b v and -b h are combined or scanned via two gates 46 which are alternatingly actuated via a signal of alternating polarity applied at terminal 48. A -b signal, which alternatingly corresponds to the -b v and -b h signals is then available at terminal 47 which can then be processed in the same manner as the -b signal of FIG. 1, e.g., by comparing same to a corresponding -b signal from a second control unit of the antilock control system. Correspondingly further signals from both control channels of the individual control unit shown in FIG. 3 may also be combined in the manner described for the -b signals.
If it is assumed that the deceleration signals -b v and -b h of both channels of the control unit of FIG. 3 have the same length, but their effect on the inlet valve 44 of the rear wheel is not blocked after 150 msec as described above with respect to FIG. 2, the signal controlling the inlet valve 44 associated with the rear wheel will have a signal duration which extends far beyond time t 2 . That is, as shown in FIG. 2, signal EV for the inlet valve 44 will include the dashed portion which extends beyond time t 2 . By multiplexing the two EV signals for the inlet valves 14' and 44, e.g. by means of the gate arrangement shown in FIG. 3, there then results the pulse-shaped curve shown in line TM of FIG. 2 from time t 2 until the end of the dashed pulse in line EV of FIG. 2.
In the above example of the invention, a signal associated with a front wheel was compared with a signal associated with a front wheel and a signal associated with a rear wheel was compared with a signal associated with a rear wheel, the distribution of the wheels being either diagonal or lateral. It is also possible, however, to compare signals of control units each associated with the wheels of an axle of the vehicle (where one axle can also be controlled by means of a single sensor at the differential of this axle). In this case the present invention can also be used as long as the control units whose signals are being compared are of the same design.
In FIG. 4 the signal generating block 30 is illustrated in more detail together with parts of the blocks 6 and 8 of FIG. 1. For example, together with the ignition switch (not illustrated) the switch 50 of FIG. 4 is closed and thus monostable circuit 30' of block 30 is set for a given time period. The output signal of this circuit 30' then generated is fed to the timing member 6' of the safety circuit 6, which emits a signal if the signal fed to its input is longer than its time constant. The signal fed to the input of timing member 6' is also fed to the input of the a second time member 8 which has the same time constant. Thus if the time members are both in order, they generate output signals at the same time which are fed to the comparison circuit 9. The comparison circuit 9 then generates an output signal, which is fed to the block 30" of block 30. The block 30" may be dimensioned according to the principles known from the U.S. Pat. No. 3,907,380. The output signal of block 30" which corresponds to a given wheel velocity curve is applied to the inputs of blocks 11 and 21 of FIG. 1.
To use and how to use a timing member such as 6' in a safety circuit 6 is known for example from U.S. Pat. No. 3,883,184 issued May 13, 1975 to Jonner et al.
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.
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An antilocking control system for the wheel brakes of a vehicle, which system includes two identically designed control units for various wheels of the vehicle and with each control unit comprising at least one wheel speed sensor, an evaluation circuit for evaluating the output signals from the sensors and for producing control signals and a brake pressure control unit responsive to the control signals from the evaluation circuit, as well as a device for testing the operability of the antilocking control system at desired time intervals. The testing device, upon receipt of a start instruction, simultaneously feeds at least one identical test signal to each of the two control units, and then compares the effect of the test signal on the two control units by comparing output signals from the two control units at given corresponding points in the two control units for at least approximate coincidence with respect to the timely occurrence and/or the magnitude of the signals and generates a control signal, e.g., to switch-off the antilock control system and/or actuate a warning device, if there is a deviation between the two signals being compared which is greater than a given value.
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RELATED APPLICATIONS
This application is a Continuation-in-Part of U.S. patent applications Ser. Nos. 08/237,114, filed May 3, 1994 for "Brassiere Blank, Brassiere and Methods of Making Same", now U.S. Pat. No. 5,479,791, and 08/420,247, filed Apr. 11, 1995, for "Shirt Blank, Shirt and Methods of Making Same."
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a shirt, bodysuit and teddy, and the blank and methods for making the same. More particularly, this invention relates to the production of a shirt or bodysuit blank on a circular knitting machine, and the production of a shirt or bodysuit from the blank having seams only at the shoulders and crotch, where applicable. Even more specifically, the invention relates to the production of a shirt, bodysuit or teddy having integrally knit compression areas to shape a wearer's body, and the blank and methods for making the same.
(2) Description of the Prior Art
Brassieres having fabric areas to define breast cups have been produced by full fashioned and reciprocating knitting machines, but blank and brassiere production tends to be slow and inefficient unless circular knitting is used. One circular knitting process is disclosed in U.S. Pat. No. 4,531,525 to Richards, wherein a brassiere blank is made on a circular knitting machine. The process includes producing a cylindrical tubular blank having a torso portion with a pair of breast cups, straps knit integrally with the torso portion, and turned welt portions at each end of the cylindrical blank. The tubular blank is slit on one side and laid flat for cutting neck and arm openings and seaming at each side to form the brassiere.
Attempts have been made on certain nether-type knitted undergarments to provide variations in the compression provided by the undergarment in areas corresponding to particular areas of a wearer's body. For example, U.S. Pat. No. 4,390,999 to Lawson et al. describes the provision of a fabric portion having a medium amount of compressive force between a highly compressive upper waist or leg portion and a low compression body portion, in order to ease the transition from the highly compressive portion to the low compression portion and reduce the resultant body bulge which can be caused by that transition. The areas providing the medium amount of compressive force are shaped and located so that they extend circumferentially about the waist or leg of the wearer in the manner of a band, and they are formed by changing the yarn used to knit various courses.
Similarly, U.S. Pat. No. 3,413,824 to Kuney discloses knitted undergarments which include form-fitting pockets in order that they can accentuate specific portions of the body. The garments are knitted using a constant stitch structure, with the stitch length being varied in selected areas to form spaced concave areas which are designed to correspond to specific regions of the wearer's body. In the illustrated embodiments, the nether garments include loosely knit regions corresponding to the buttock cheeks and a tightly knit seam piece extending vertically between the loosely knit regions. Though mentioning broadly that the structure could be used with brassieres, the Kuney patent does not disclose how the structure can be incorporated into such a brassiere.
U.S. Pat. No. 3,425,246 to Knohl discloses a knitted brassiere having extra courses of elastic yarn knitted into the breast cups to shape the cups by providing fullness therein.
U.S. Pat. No. 5,081,854 to Lonati describes a one-piece body garment which is knit on a circular knitting machine. An elastic thread or threads can be inserted in the waistband portion to form an elastic band at the waistband. These garments can tend to lack sufficient breast support for women, and fail to provide means for enhancing the appearance of the wearer's body.
Blanks for the production of knitted shirts are conventionally knit in flat or tubular form. The blanks are then cut to form arm openings and a neck opening, seamed along the side if necessary, and the bottom of the shirt is hemmed. To complete the shirt, a separately manufactured neckband is then sewn to a neck opening of the T-shirt, usually with a double row of stitching, and the arm openings are then finished, usually either by hemming or attaching banding, to thereby form a finished shirt. Because all of these seaming processes require the input of labor, each seaming step increases the manufacturing costs of the shirt.
Thus, a need exists for a method of making shirts which requires a minimal amount of seaming to provide an efficiently and rapidly producible garment, and blanks and shirts requiring only a minimal number of seams. In addition, a need exists for a shirt, bodysuit, and teddy construction which can provide shaping support for a wearer's body and can accommodate the curves of various wearer's bodies, and which can be rapidly and easily produced using only a minimal number of manufacturing steps and labor input.
SUMMARY OF THE INVENTION
With the foregoing in mind, it is therefore an object of this invention to provide a method of making a circular knit, tubular blank from which a shirt may be made with only a minimal number of seams, and which can be made to provide shaping support for the wearer's body.
It is a further object of this invention to provide a method of making a circular knit, tubular blank from which a teddy or bodysuit can be made, and which requires only a minimal number of manufacturing steps for the conversion of the blank into the completed garment.
It is also an object of the invention to provide a circular knit blank for the manufacture of a shirt which provides shaping support for a wearer.
It is an additional object of the invention to provide a circular knit blank for the manufacture of a bodysuit or teddy which provides shaping support for a wearer.
It is a further object of the invention to provide methods of making a shirt, bodysuit and teddy having knit-in shaping support using only a minimal number of manufacturing steps.
An even further object of the invention is the provision of a shirt, bodysuit and teddy having knit-in shaping support and only a minimal number of seams.
In accordance with the present invention there is described a method of manufacturing a circular knit blank for making a shirt which includes knitting a series of courses defining a non-raveling edge. In a preferred form of the invention, this non-raveling edge is provided in the form of a cylindrical tubular torso encircling portion in the form of a turned welt, as this enables the production of a shirt without the conventionally required hemming of the lower portion.
A middle torso portion for covering the areas about the waist of a wearer's body is then knit to the torso encircling portion as a tubular fabric portion. This middle torso portion is knit so as to be compressible in order that it can provide compressive support to the underlying portions of a wearer's body.
An upper torso portion comprising a series of courses defining a tubular fabric portion is then knit to the middle torso portion. The upper torso portion is knit to have greater cross-stretch (i.e. coursewise stretch) than the middle torso portion, preferably by lengthening the stitches making up the upper torso portion. In this way, when the blank is converted into a finished shirt, the upper torso portion does not compress the wearer's breasts in the manner that the rib and stomach areas covered by the middle torso portion are compressed.
The upper torso portion also desirably includes a pair of breast cups integrally knit into a front portion thereof, the cups being defined by two areas in which the fabric is in simple knit courses with these areas being separated one from another. In a preferred embodiment of this invention, the breast cups are separated one from the other by a central area of gathered panels in which succeeding courses vary between simple knit and welt knit courses. In the embodiment of the shirt blank including breast cups, the rear portion of the blank desirably maintains a constant knit structure throughout the middle and upper torso portions, though the stitch lengths can be lengthened at the upper torso portion in the manner discussed above.
A shoulder portion is then knit in tubular form to the upper torso portion. The shoulder portion includes elongated areas in which the courses are simple knit, with the areas being divided by elongated panel areas in which successive courses are also simple knit. Lastly, the circularly knit tubular blank is completed by knitting several courses forming a non-raveling edge.
The shirt of the present invention is made from the circular knit tubular blank by cutting and removing selected portions of the blank to form a neck opening and arm openings. Front and rear portions of the shoulder portions are sewn together, and banding and the like can be added to finish the arm and neck openings, or the openings can be hemmed or selvaged. There is thus provided a shirt made from a blank of knit construction which can be shaped to the contours of a wearer's body, and requires only a minimal number of steps for its production.
A blank for a bodysuit or teddy is produced in a similar manner to that of the shirt. A series of courses defining a non-raveling edge is knit in tubular form. A lower torso portion is knit to the non-raveling edge, and desirably includes a region proximate the non-raveling edge which has a modified knit configuration for forming the crotch portion of the garment. For example, the crotch forming portion of the blank can be knit to form a terry pile surface in a region which will correspond to the wearer facing portion of the crotch of the garment.
A middle torso portion is knit to the lower torso portion, and is knit so that a garment made therefrom will provide compressive support to underlying regions of a wearer's body when the garment is worn.
An upper torso portion is then integrally knit to the middle torso portion. The upper torso portion is knit to have greater cross-stretch than the middle torso portion, preferably by lengthening the stitches used to form the upper torso portion. In this way, when the blank is converted into a finished bodysuit or teddy the upper torso portion does not compress the wearer's breasts in the manner that the rib and stomach areas covered by the middle torso portion are compressed.
It is noted that the lower torso portion can be compressive in the same manner as the middle torso portion, or it can be less compressive in the manner of the upper torso portion.
The upper torso portion also desirably includes a pair of breast cups integrally knit into a front portion thereof, the cups being defined by two areas in which the fabric is in simple knit courses with these areas being separated one from another. In a preferred embodiment of this invention, the breast cups are separated one from the other by a central area of gathered panels in which succeeding courses vary between simple knit and welt knit courses. In the embodiment of the bodysuit and teddy blank including breast cups, the rear portion of the blank desirably maintains a constant knit structure throughout the middle and upper torso portions, though the stitch lengths can be lengthened at the upper torso portion in the manner discussed above.
A shoulder portion is then knit in tubular form to the upper torso portion. The shoulder portion includes elongated areas in which the courses are simple knit, with the areas being divided by elongated panel areas in which successive courses are also simple knit. Lastly, the circularly knit tubular blank is completed by knitting several courses forming a non-raveling edge.
The bodysuit and teddy of the present invention are made from the circularly knit tubular blank by cutting and removing selected portions of the blank to form a neck opening, arm openings, and leg openings and a crotch portion therebetween. Front and rear portions of the shoulder portions are sewn together, and banding and the like can be added to finish the arm and neck openings, or the openings can be hemmed or selvaged. Front and rear blank portions are then joined by sewing or the like to form a bodysuit. Alternatively, snaps, hook and loop fasteners, or other types of releasable fasteners may be attached to front and rear blank portions at the crotch region, to form a teddy.
For purposes of this invention, a bodysuit is defined as a garment having upper and lower torso covering portions with a crotch portion which extends between a wearer's legs, with front and rear portions of the crotch portion being sewn or otherwise permanently attached together. In contrast, a teddy is defined as a garment like that of the bodysuit, but in which the front and rear portions of the crotch portion are joined by way of releasable fasteners, whereby the garment can be opened at the crotch. For purposes of the claims, a garment adapted to cover substantially the entire torso of a wearer is meant to encompass both bodysuits and teddies. However, it is noted that the specific garments disclosed can be used as under or outer garments, and may be used by men, women and children alike. The crotch portion can be specially configured to accommodate either male or female anatomy, at the preference of the manufacturer.
There is thus provided a bodysuit and teddy made from a blank of knit construction which can be shaped to the contours of a wearer's body, have selected regions of compressive body control, and require only a minimal number of steps for their production.
Other objects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating an embodiment of a shirt according to the present invention, the shirt being made from the blank shown in
FIGS. 2a and 2b show enlarged views of the knit structures shown in FIG.1
FIG. 3 is a perspective view of a blank for making the shirt of FIG. 1;
FIG. 4 is a perspective view of a bodysuit or teddy according to the present invention, the bodysuit or teddy being made from the blank shown in FIG. 5;
FIG. 5 is a perspective view of a circular knit blank in accordance with the present invention and from which the bodysuit or teddy of FIG. 4 is manufactured.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, FIG. 1 shows a preferred embodiment of the finished shirt of the present invention referenced generally at 10. The shirt 10 includes a non-raveling edge portion which is preferably in the form of a cylindrical tubular torso encircling portion 22, e.g. a turned welt. A middle torso portion 24 in the form of a fabric tube is knitted to the torso encircling portion 22 and is designed to cover the area of a wearer about the lower ribs and the waist, and below the waist as desired. It is particularly preferred that the middle torso portion be of sufficient length to enable a wearer to tuck the lower end of the shirt into his or her pants, though other lengths are within the scope of the invention, such as a length which enables the shirt lower edge to fall just above a wearer's waist. The middle torso portion is knit so that is can provide compressive support to the underlying portions of a wearer's body.
An upper torso portion 27 comprising a series of courses defining a tubular fabric portion is knit to the middle torso portion 24 and includes a front upper torso portion 27a and a rear upper torso portion 27b. The front upper torso portion 27a, in a preferred embodiment of the invention, includes a pair of integrally knit breast cups 26 defined by areas in which the courses are simple knit and have succeeding areas of courses varying between simple knit and welt knit courses. The courses defining the front torso portion 27a differentially shape the breast cups 26. The upper torso portion 27 includes a rear upper torso portion 27b above the middle torso portion 24 in which the fabric is preferably in simple knit courses.
In a preferred embodiment of this invention, the breast cups 26 are defined by areas in which the courses are simple knit with the breast cup areas 26 being separated by a center gathered panel area 25, shown in FIGS. 1 and 3, in which the courses vary between simple and welt knit courses. The gathered portion 25 is made by pulling the cams of the knitting machine away from the butts, allowing the shorter butt needles to pass through underneath the cams to hold the stitch for a predetermined number of courses, say 3 to 20 and preferably 10 to 12. The needles are then raised to clear the stitch to form a pleat, and the process is repeated until the gather is formed. Needles for tuck or pleat can be made without using cams by the selection of the needles to hold the stitch by knitting at welt height. The cams are then returned to the cylinder so that the short butt needles will rise.
The upper torso portion 27 also desirably is knit to have greater cross-stretch than the middle torso portion 24, in order that the breast region of the wearer is not undesirably compressed. This is preferably achieved by forming the upper torso portion 27 from longer stitches than those used to form the middle torso portion 24. In this way, the compression provided by the garment to the underlying body portions of a wearer is reduced in the area of the breasts of the wearer, thereby preventing the breasts from experiencing the discomfort that compression would inflict on these areas. Further, the stitches are preferably lengthened starting immediately below the breast region of the wearer, enabling the compressive middle torso portion to assist in supporting the breasts, in addition to providing a more slimming appearance to the underlying regions. The differences in stitch lengths are shown in FIGS. 2a and 2b, which show the knitted structure of the upper torso 27 and the middle torso portion 24, respectively. Though the knitted stitches depicted are in simple form, it is noted that different types of knit stitches could be used to perform the invention.
A shoulder portion 29 is then knit to the upper torso portion in the form of a tubular fabric portion. The fabric forming the shoulder portion 29 is preferably knit in simple knit courses with patterns. Front portions of the shoulder portion are sewn to rear portions of the shoulder portion at seams 32 to form shoulder straps, thereby forming a completed shirt.
Turning now to FIG. 3, there is shown a shirt blank 30, made on a high speed circular knitting machine, from which the shirt 10 is produced. The blank 30 is in tubular form, and is knit to include portions which correspond to the portions of the shirt described in FIG. 1. The reference characters corresponding to those used with reference to FIG. 1 will be applied in FIG. 3, with the addition of prime notation.
The torso encircling portion 22' in the blank 30 is preferably formed as a cylindrical tubular fabric portion in the form of a turned welt. A middle torso portion 24' is knit to the torso encircling portion 22' as a tubular fabric portion, and is knit so as that it provides compressive support on underlying portions of a wearer's body when it is converted into a shirt.
An upper torso portion 27' is then knit to the middle torso portion 24'. The upper torso portion 27' is knit in tubular form to include a front upper torso portion 27a' and a rear upper torso portion 27b'. The upper torso portion 27' is knit to have a greater degree of cross-stretch than the middle torso portion 24', preferably by using longer stitches to form the upper torso portion than those which are used to form the middle torso portion.
In a preferred embodiment of the invention, the blank includes a pair of integrally knit breast cups 26' on the front upper torso portion 27a' thereof. The breast cups 26' are defined by areas in which courses are simple knit, with the areas being spaced apart from one another. In a particularly preferred embodiment of the invention, the breast cups 26' are separated one from the other by areas of gathered panels 25' in which succeeding courses vary between simple knit and welt knit courses, the knitting of courses defining the front upper torso portion differentially shaping the breast cups with respect to the gathered panels. As will be understood, the degree of shaping will vary, and may be taken into account in accomplishing sizing of the shirt.
A shoulder portion 29' is knit to the upper torso portion 27', and preferably includes elongated areas in which the courses are simple knit, with the areas being divided by an elongate panel area. In this way, a cutting pattern 33 can be formed in the knit structure of the blank itself, thereby enabling a worker to cut portions of the blank to form arm openings and define a neck section, without the need for additional patterning or marking. In addition, the yarn feeds can be manipulated in order that less yarn is fed to the portions of the blank 30 which are to be cut and removed, thereby reducing the amount of material waste produced as a result of shirt formation.
The blank is finished by knitting a series of courses in the form of a non-raveling edge 34. The non-raveling edge 34 serves to prevent raveling of the blank 30 during the time between when the blank is produced and when it is converted into a completed shirt 10.
The various portions of the circular knit tubular shirt blank 30 are integrally knit together and have stitch constructions as described hereinabove. Thus, the method of manufacturing the blank will become more clearly understandable and may be characterized as knitting a series of courses defining a first cylindrical tubular portion in the form of a turned welt 22', and then knitting to the turned welt portion a series of courses defining a middle torso portion 24'. The middle torso portion 24' is knit so as to have limited cross-stretch, in order that it will provide compressive support to the portions of a wearer's body located underneath the middle torso portion when the blank is converted into a shirt.
An upper torso portion 27' formed by a series of courses defining a tubular fabric portion is then knit to the middle torso portion 24'. The upper torso portion 27' is knit to have a greater degree of cross-stretch than that of the middle torso portion 24', preferably by knitting the upper torso portion from longer knitted stitches or loops than the middle torso portion. In preferred embodiments of the invention, the upper torso portion can be knit to include first and second breast cups 26' in which spaced apart portions of the upper torso portion are simple knit. In a particularly preferred embodiment, the breast cups 26' are spaced apart by gathered panels 25', as discussed above.
A shoulder portion 29' is then knit to the upper torso portion 27', and preferably is knit to include a plurality of elongated areas in which the courses are simple knit, with these elongated areas being separated from each other by elongated panel areas. To complete the blank, a plurality of courses defining a non-raveling edge 34 are then knit to the shoulder portion 29'.
The manufacture of the shirt 10 is performed as follows, with particular reference being made to FIG. 3. The tubular blank 30 is cut along the cutting pattern, which is indicated by dotted lines 33 shown in FIG. 3. The cut portions are removed from the blank to thereby define arm openings 38 and a neck opening 44. The thus cut blank 30, as shown in FIG. 3, is then joined at seams 32 to connect front and rear portions of the shoulder portion 29 at opposite sides of the neck opening 44, to thereby form a completed shirt.
Banding and the like 39 may be added at the arm openings and neck opening to finish off the shirt, or raw arm opening and neck opening edges can be hemmed or selvaged to form a finished shirt.
Simple knit stitches are used to distinguish those stitch constructions possible on a circular knitting machine and in which yarn is taken into a needle during each rotation of the cylinder, such as plain, purl, tuck and combinations thereof. References to welt knit are intended to encompass miss-stitch or float stitch constructions in which loops in certain courses are held without additional yarns being taken and then knit into subsequent courses, thereby gathering the courses together and providing the characteristic turned welt or panel effect referred to above.
FIGS. 4 and 5 illustrate another embodiment of the invention, namely a bodysuit or teddy 40 and a blank for making the bodysuit or teddy. Again, like numbers are used to represent like elements on the garment and the blank, with the common elements being primed on the blank.
The blank 130 is made similarly to the blank 30 in FIG. 3, but is extended beyond the turned welt portion 22' of that blank to form a lower torso portion 42'. The blank 70 includes a series of courses forming a non-raveling edge 72 about a lower portion of the blank. A lower torso portion 42' is knit in the form of a tubular fabric portion to the non-raveling edge 72. This lower torso portion 42' preferably includes a crotch region 43' which has a modified stitch construction of the type conventionally used to form a panty crotch portions. Particularly preferred is a knit construction which includes a terry surface which is adapted to extend along a wearer-contacting surface of the crotch portion of a garment made from the blank 70.
A middle torso portion 24' is integrally knit to the lower torso portion 42' in the form of a tubular fabric portion. This middle torso portion a 24' is knit to have limited cross-stretch which enables the portion of a garment made from the blank 70 which corresponds to the middle torso portion to compressively support a portion of a wearer's body which it covers.
An upper torso portion 46' is knit in tubular form integrally with the middle torso portion 24', and includes for purposes of describing location a front upper torso portion 46a' and a rear upper torso portion 46b'. It is noted, however, that these portions form a part of the integrally knit tubular upper torso portion 46 rather than comprising separate elements. The upper torso portion 46' comprises a series of courses defining a pair of breast cups 48' on the front upper torso portion 46a' defined by areas in which the courses are simple knit and having succeeding courses varying between simple knit and welt knit courses. In a particularly preferred embodiment of the invention, the breast cups 48' are separated one from the other by areas of gathered panels 50' in which succeeding courses vary between simple knit and welt knit courses, the knitting of courses defining the front upper torso portion differentially shaping the breast cups with respect to the gathered panels.
A shoulder portion 52' is then knit to the upper torso portion 46' to define front and back fabric straps 53a and 53b, each having an elongated patterned area in which the courses are simple knit with the areas being divided on the blank by an elongated panel area in which succeeding courses vary between simple knit and welt knit courses. The blank 70 is completed by knitting several courses forming a non-raveling edge 64.
The bodysuit or teddy 40 shown is FIG. 4 is made from blank 70, shown in FIG. 5, by cutting and removing portions of the blank to form a neck opening 56, a pair of arm holes 54', and to define leg openings 45' having a crotch portion 43' located therebetween, as indicated by the cutting lines 66 on FIG. 5. The waste fabric is removed so as to define the front shoulder straps 53a and the rear shoulder straps 53b which are sewn together along seams 60 to complete the upper portion of the bodysuit or teddy. Front and rear portions of the blank 70 can be attached together along the crotch portion 43, as indicated at 62 in FIG. 4. The attachment can be a permanent attachment, such as by sewing, or releasable fasteners such as snaps, buttons, hook and pile fasteners and the like can be used to form a teddy garment.
Banding and the like 58 may be added to finish off the bodysuit or teddy 40 at the neck, arm an leg openings 56, 54 and 45, respectively, or the edges may be selvaged or hemmed in a conventional manner. In addition, a supplemental crotch lining (not shown) can be attached in a conventional manner, where desired.
The shirt, bodysuit and teddy blanks disclosed herein can thus be manufactured rapidly on high speed circular knitting machines and such garments can be manufactured from these blanks utilizing only a minimal number of seams. The shirt, bodysuit and teddy disclosed hereinabove can be used as either an outer or undergarment, depending on the materials used to manufacture the shirt and the wearer's desires, and can be used by women, men and children alike.
In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.
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This invention discloses a shirt, bodysuit and teddy having built-in breast cups and/or selected areas of varying cross-stretch in order to provide compressive support for a wearer's body, and methods and blanks for manufacturing such shirts, bodysuits and teddies. In particular, circular knitting operations are used to produce garments having areas of compressive support in the middle torso region, and a greater amount of cross-stretch in the region corresponding to a wearer's breast area. In addition, the garments can include integrally-knit breast cups and a gathered panel located between the breast cups. Shirts made according to the present invention can include a turned welt about their lower or shirttail ends, in order to eliminate the need for hemming the lower shirt portion. Blanks and methods for making the garments are also disclosed, which require only a minimal number of manufacturing operations to be converted into completed garments.
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This patent application claims the benefit of U.S. Provisional Patent Application No. 60/778,404 filed Mar. 3, 2006.
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to devices and methods for shared-medium data-transmission networks, and particularly, using forward error correction (FEC) coding in Ethernet networks, as specified in the IEEE 802.3, clause 65.
Ethernet technology is one of the most common digital-networking technologies. Specified in the Institute of Electrical and Electronics Engineers (IEEE) standard 802.3, the technology has a large installed base of compatible network devices. (The 2005 edition of the IEEE 802.3 standard is filed together with this document and is hereby incorporated by reference as if fully set forth herein.) Ethernet technology continues to evolve with newer and faster variants, such as the Gigabit Ethernet, which provides network speeds of one gigabit per second.
For several decades, Ethernet technology has been widely used in local-area networks (LANs). More recently, Ethernet technology has been used with increasing frequency in metro-area network (MAN) and other wide-area network (WAN) applications. Such networks include optical networks, such as passive optical networks (PONs). In WAN applications, signal attenuation and budget constraints on the network link have greater importance because of the distances involved for the WAN connectivity, and because of the optical power splitters that may be used along a network link between a transmitter and a receiver.
At some point along the network link, a signal may be attenuated and distorted to such a degree that the information the signal carries cannot be extracted because of: the limited sensitivity of the receiver, noise in the propagation medium, signal source-related noise (such as inter-symbol interference and mode-partition noise), and other sources of noise, attenuation, and distortion. But long before this point is reached, the signal-to-noise ratio (SNR) of the signal deteriorates, and the bit error rate (BER) of the signal increases beyond the tolerable level for a typical application.
Forward Error Correction (FEC) is one method for improving the BER of a received signal with low SNR. The operation of FEC is described in Khermosh, US Patent Publication No. 20050005189 (assigned to the assignee of the present invention and henceforth referred to as Khermosh '189), which patent application is incorporated by reference for all purposes as if fully set forth herein. FEC is a coding technique that uses additional (i.e. redundant, or parity-check) symbols as part of a transmission of a digital signal sequence through a physical channel. The symbols are a type of error control codes. But, because of the presence of sufficient redundancy, when errors corrupt the received signal, the receiver not only recognizes the errors, but also corrects the errors without requesting retransmission. In practice, the improvement in the BER achieved through the use of FEC is known as “coding gain.”
Adding FEC capability to a legacy Ethernet network may cause errors in the media access control (MAC) layer of the non-FEC-capable (i.e. legacy) network elements. Moreover, applying FEC only to the payloads of data packets would not affect network-link budget constraints because packet headers, which carry destination information and frame boundary fields of the packets, would not benefit from the improved BER of the payloads. On the other hand, applying FEC separately to the headers and payloads can make the headers unrecognizable to the “non-FEC” network elements. These headers should be decoded in a reliable manner to provide line immunity. Furthermore, the headers should be decoded more reliably than the FEC protection so as not to limit network performance.
The method of packet-based FEC is specified in the IEEE 802.3, clause 65. Specific FEC code of Reed Solomon (RS) (255,239,8) code was selected therein, and specific S_FEC and T_FEC delimiters were selected for the line. The delimiters are a sequence of 8-bit/10-bit (8B/10B in 1000BaseX) code symbols. The 8B/1B code is the physical coding sub-layer (PCS) line code of the 1G Ethernet as specified in the IEEE 802.3, clause 36.
It would be desirable to have devices and methods for improving BER for a given network link budget, and conversely, for increasing the network link budget for a given BER, on Ethernet-compatible networks having non-FEC-capable legacy network elements.
SUMMARY OF THE INVENTION
It is the purpose of the present invention to provide devices and methods for shared-medium data-transmission networks, and particularly, using forward error correction (FEC) coding in Ethernet networks, as specified in the IEEE 802.3, clause 65.
For the purpose of clarity, several terms which follow are specifically defined for use within the context of this application. The terms “frame” and “packet” are used interchangeably herein. The term “dataword” is used in this application to refer to an uncoded, 8-bit data segment. The term “codeword” is used in this application to refer to a coded, 10-bit dataword transmitted after passing through the PCS. The term “correlator” is used in this application to refer to an engine that tests for a match or correlation. In the context of this application, a symbol set acts as a delimiter. The term “hamming-distance indicator” is used in this application to refer to an indicator of the hamming distances from a correlation sequence. The term “threshold-compared hamming-distance indicator” is used in this application to refer to the hamming-distance indicator after being compared a hamming-distance threshold. The term “threshold-compared multiple-correlation indicator” is used in this application to refer to the threshold-compared hamming-distance indicator after being compared to a multiple-correlation threshold.
Additional descriptions of coding and decoding schemes may be obtained from Shu Lin & Daniel J. Costello, Jr., Error Control Coding: Fundamentals and Applications , Prentice Hall Inc., 1983. The combinatorial notation used in this application for combinations is, for example: ( 10 2 )=comb(10, 2)=fact(10)/(fact(10-2)fact(2)), where the factorial, fact(10)=10×9×8×7×6×5×4×3×2×1.
In accordance with the principles of the present invention, methods are provided for reliable decoding of the special packet delimiters (S_FEC, T_FEC_E, T_FEC_O). As explained below, the reliable decoding is non-trivial as the hamming distance (i.e. the bit distance between two codewords) of the correlators alone are not sufficient enough for the decoding.
Therefore, according to the present invention, there is provided for the first time a method for improving data correlation using a multiple-correlation state-machine, the method including the steps of: (a) pre-processing a data frame having a plurality of symbol sets, wherein each symbol set demarks a respective frame field of the frame, to provide a threshold-compared hamming-distance indicator; (b) comparing the threshold-compared hamming-distance indicator with at least one multiple-correlation threshold to provide a threshold-compared multiple-correlation indicator; and (c) combining the threshold-compared hamming-distance indicator and the threshold-compared multiple-correlation indicator to determine a match/no-match comparison indicative of field of said frame.
Preferably, the step of pre-processing includes the steps of: (i) checking the frame using at least two correlators matched to at least two symbol sets to provide a correlation sequence; (ii) analyzing the correlation sequence to provide a hamming-distance indicator; and (iii) comparing the hamming-distance indicator with a hamming-distance threshold to provide the threshold-compared hamming-distance indicator.
More preferably, each frame includes a first symbol-set field delimiting a beginning of a preamble field of each frame.
More preferably, each frame includes a second symbol-set field delimiting an end a parity-bytes field of each frame.
More preferably, each frame includes a third symbol-set field delimiting an end of each frame.
Most preferably, at least two correlators are based on the second symbol-set field and the third symbol-set field.
Preferably, the method further includes the step of: (d) prior to the step of combining, comparing a BER of the frame to a BER threshold.
Preferably, the step of combining includes forming a logical-AND of the threshold-compared hamming-distance indicator and the threshold-compared multiple-correlation indicator.
Preferably, the data frame is an FEC-protected data frame.
Preferably, the method further includes the step of (d) prior to performing step (c), iterating step (b), wherein the comparing includes comparing each indicator, of a plurality of indicators, with each multiple-correlation threshold to provide a threshold-compared multiple-correlation indicator.
According to the present invention, there is provided for the first time a device configured to operate according to the method described above.
According to the present invention, there is provided for the first time a method for improving data correlation using a weighted-correlation, the method including the steps of: (a) pre-processing a data frame having a plurality of symbol sets, wherein each symbol set demarks a respective frame field of the frame, to provide a threshold-compared hamming-distance indicator; (b) weighting the threshold-compared hamming-distance indicator to provide a weighted hamming-distance indicator according to a parameter set; (c) comparing the weighted hamming-distance indicator with a weighted-correlation threshold to provide a threshold-compared weighted-correlation indicator; and (d) combining the weighted hamming-distance indicator and the threshold-compared weighted-correlation indicator to determine a match/no-match comparison indicative of a field of said frame.
Preferably, the step of pre-processing includes the steps of: (i) checking the frame using at least one correlator matched to at least one symbol set to provide a correlation sequence; (ii) analyzing the correlation sequence to provide a hamming-distance indicator; and (iii) comparing the hamming-distance indicator with a hamming-distance threshold to provide the threshold-compared hamming-distance indicator.
More preferably, each frame includes a first symbol-set field delimiting a beginning of a preamble field of each frame.
More preferably, each frame includes with a second symbol-set field delimiting an end a parity-bytes field of each frame.
More preferably, each frame includes a third symbol-set field delimiting an end of each frame.
Most preferably, at least two correlators are based on the second symbol-set field and the third symbol-set field.
Preferably, the step of weighting is based on bits having respective symbol sets distanced one bit from a correlated delimiter of the respective frame field.
Most preferably, the step of weighting is dependent on a BER of the frame.
Most preferably, the method further includes the step of: (e) prior to the step of combining, comparing a BER of the frame to a BER threshold.
Preferably, the step of combining includes forming a logical-AND of the weighted hamming-distance indicator and the threshold-compared weighted-correlation indicator.
Preferably, the data frame is an FEC-protected data frame.
According to the present invention, there is provided for the first time a device configured to operate according to the method described above.
These and further embodiments will be apparent from the detailed description and examples that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1 shows the format of the field blocks of a coded packet frame, according to the present invention;
FIG. 2 is a simplified schematic block diagram of the data flow in a correlator state machine, according to the present invention;
FIG. 3 is a high-level flowchart of the processing steps in the double-correlation method, according to the present invention;
FIG. 4 is a high-level flowchart of the processing steps in the weighted-correlation method, according to the present invention;
FIG. 5 is a high-level flowchart of typical pre-processing steps in prior-art methods;
FIG. 6 is a schematic flowchart of the processing steps in a multiple-correlation method, according to the present invention;
FIG. 7 is a schematic flowchart of the processing steps in the weighted-correlation method, according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to devices and methods for shared-medium data-transmission networks, and particularly, using forward error correction (FEC) coding in Ethernet networks, as specified in the IEEE802.3, clause 65. The principles and operation for shared-medium data-transmission networks, according to the present invention, may be better understood with reference to the accompanying description and the drawings.
Referring now to the drawings, FIG. 1 shows the format of the field blocks of a coded packet frame, according to the present invention. A frame 10 is shown having: a start-symbols field 12 , signifying the beginning of the packet; a preamble field 14 , which serves as a synchronizing sequence to allow the PCS to synchronize with received frame 10 (i.e. Ethernet packet); a start-frame delimiter (SFD) field 16 , which is a special sequence of 10101011, signifying the start of the information-carrying part of frame 10 ; a header field 18 , which combines a destination address of the receiver, a source address of the transmitter, and an indicator of the length/type of a data field 20 of frame 10 ; data field 20 , which is a variable length field of between 46 and 1586 bytes (if necessary, data field 20 is padded with all zeros, so that the length of data field 20 is at least 46 bytes); a frame-check sequence (FCS) field 22 , which is a dword (i.e. 4 byte data segment) of frame 10 , having a cyclic-redundancy-check value used to verify the integrity of received frame 10 ; a stop-symbols field 24 , which signifies the end of frame 10 ; a parity-bytes field 26 , which has parity-check bytes resulting from encoding of an information block (which can include, for example, preamble field 14 , SFD field 16 , header field 18 , data field 20 , and FCS field 22 . In preferred embodiments, all five of these fields are block encoded.) in frame 10 ; a second stop-symbols field 28 , similar to stop-symbols field 24 , which delimits parity-bytes field 26 ; and an inter-packet gap (IPG) field 30 .
Strictly speaking, the IPG field 30 is not part of frame 10 . Rather, IPG field 30 is a time gap, or “buffer zone,” between consecutive packets on the network. Nevertheless, because the Ethernet standard specifies handling of IPG field 30 , IPG field 30 is included in FIG. 1 .
The FEC coding in the present invention operates according to a Reed Solomon (RS) GF(2 8 )−(255,239,8) code. In such a coding scheme, for every 239 bytes of data, there are 16 parity bytes added to allow the code to correct up to eight bytes with errors. The field polynomial is: f(x)=x 8 +x 4 +x 3 +X 2 +1, and α is the primitive of the field, generating polynomial:
g
(
x
)
=
∏
i
=
0
15
(
x
-
α
i
)
.
The actual FEC coding used is a systematic block-coding type. Block coding means coding of blocks of k information source symbols into blocks of code symbols or codewords of n symbols. (A symbol can be a bit, a byte, a 16-bit word, or any other binary or non-binary character or string of characters.) As redundancy implies, n>k. The rate of such code is defined as R=k/n. A systematic block code is a code where the information symbols of a block to be coded are carried into the corresponding codeword, and the parity-check symbols (of parity-bytes field 26 ) are added to the codeword. Thus, the information symbols remain visible after the block is coded.
Merging the FEC coding with the data information, the additional information is added to the media access control (MAC) layer. Each frame 10 with the length of L bytes is extracted with 2t(L/k) bytes for a constant rate code, R, with a correction length of t, where L is between 71 to 1611, t is equal to 8 and k equal to 239. Frames with length under k bytes (where n, the frame length=239 bytes) are “padded” with zeros (virtually, without sending the zero-bytes). The new packet is coded with 2t (=16) parity bytes added to the frame. The received packet can contain one to seven blocks; where the maximum block size is 239 data bytes plus the 16 parity bytes.
The frame boundaries of frame 10 are not protected by the RS code. Therefore, the frame boundaries are replaced by a stream of symbols which are correlated for protected detection as a way of ensuring detection of the frame boundaries (for a more detailed description of such correlation, see Khermosh '189 and/or the IEEE 802.3 specification, clause 65). The stream of symbols is constructed from 8B/10B codewords.
At the beginning of frame 10 , start-symbols field 12 provides the first byte of the packet, which is indicated upon the detection of the S_FEC symbol set (i.e. /K28.5/D6.4/K28.5/D6.4). The symbol set notations and sequences used in this document are defined in the IEEE 802.3 specification (e.g. in chapter 36 of the specification, which describes the PCS). The notations and sequences are known to those skilled in the art. Stop-symbols field 24 provides the last byte of data field 20 , which is indicated upon the first detection (i.e. end of stop-symbols field 24 ) of the T_FEC_O or T_FEC_E symbol sets.
For T_FEC_E with negative disparity, the symbol set is T/R/K28.5/D10.1/T/R. For T_FEC_E with positive disparity, the symbol set is T/R/K28.5/D29.5/T/R. For T_FEC_O, the symbol set is T/R/R/I/T/R. At the end of frame 10 , stop-symbols field 28 provides the last byte of the parity-bytes field 26 , which is indicated upon the detection of the T_FEC_E symbol set. Networks with non-FEC-capable legacy network elements do not cause errors as explained in detailed in Khermosh '189.
An analysis of the correlation scheme was performed. The following assumptions, which are the characteristics of the code and are deduced from the 8B/10B codeword tables, were made in the correlator analysis:
(a) the distance of T from a data word is one bit; (b) the distance of K28.5 from a data word is one bit; (c) the distance of R from a data word is one bit; (d) the distance of T from R is two bits; and (e) the distance of K28.7 from any codeword is at least two bits and one bit from K28.5 (and K28.1).
The correlation scheme counts errors in all positions. In scenarios in which the positions are specified, the probability of error is reduced.
The current correlator performance, for the T_FEC_O symbol set (i.e. T/R/R/K28.5/D/T/R) and the T_FEC_E symbol set (i.e. T/R/K28.5/D/T/R), results in:
(a) a worst-case distance from a random data-stream of five, (b) a three-error limit will cause misdetection; and (c) the probability of error is ( 60 3 )×(10 −4 ) 3 =3.4×10 −8 ; (d) for the S_FEC symbol set, error does not arise in the analysis because the scheme is not searching for S_FEC symbol set until parity-bytes field 26 ends; (e) for a distance of the T_FEC_E symbol set (i.e. T/R/K28.5/D/T/R) from a shifted word which ends at the end of a frame (e.g. D/D/D and /D/T/R) of three:
(i) a two-error limit will cause misdetection; (ii) the probability of error is ( 60 2 )×(10 −4 ) 2 =1.5×10 −6 .
The present invention includes two principal method of correlation: a double-correlation state-machine method and a weighted-correlation method. The double-correlation state-machine method keeps the same correlators as described in the analysis above. The problem in T_FEC detection is solved by enhancing the detection criteria. Instead of checking for a single occurrence of correlation match, two occurrences of the T_FEC correlator are verified.
The data is not processed off-line because a positive identification of the start of the packet is made only at the second T_FEC symbol set. Thus, the FEC decoding machine (i.e. state machine) must know the parity-bytes location in real-time. Therefore, a buffer is used for that handle the real-time processing demand. The minimal size of the buffer is: (number of parity bytes)+2(T_FEC length), or (7×16)+12=124 bytes. Typically, a 128-byte data buffer is used. The buffer is typically implemented with a fixed delay, but can also be implemented with a variable delay (i.e. “first-in-first-out” or FIFO).
The state machine is modified to detect only the T_FEC symbol set at the end of parity-bytes field 26 . Only the T_FEC_E symbol set can arrive after the parity bytes, therefore, only the T_FEC_E symbol set is detected. A few more data words are checked following T_FEC symbol set; otherwise, the second T_FEC symbol set can be mistaken as the first T_FEC symbol set. The state machine checks for additional “idle-points” after the correlator, each idle-point adds a two-bit distance. For determining the number of additional idle-points to search for, as in other correlator selection, two criteria are checked: (1) distance from random data, and (2) distance from idle-points.
The end of parity-bytes field 26 provides deterministic knowledge of the packet length. The length of the packet is the total length minus the correlator length minus the number of predicted parity bytes. A shadow counter is used to count the actual data length, based on the formulation of the length. However, since the number of bytes can be even or odd, it is necessary to determine the correct number of bytes via a secondary method that confirms the shadow counter.
To determine the correct number of bytes, the T_FEC symbol set at the end of each packet is checked whether the symbol set is odd or even (i.e. T_FEC_O or T_FEC_E, respectively) by selecting the value with the lower distance. The value is stored, and added to the frame as an indication of the distance, enabling the correct length to be determined. The end of frame signal (i.e. stop-symbols field 28 ), and other control signals such as parity-bytes field 26 , are created by the buffer control. The probability of misdetection for two idle-points is ( 160 5 )(10 −4 ) 5 =8×10 −12 , and the probability of misdetection for three idle-points is ( 180 6 )(10 −4 ) 6 =4×10 −14 .
FIG. 2 is a simplified schematic block diagram of the data flow in a correlator state machine, according to the present invention. FIG. 2 shows the correlation scheme described above. Correlators 40 include an S_FEC detector, a T_FEC_E 2-disparity detector and a T_FEC_O 2-disparity detector, and a 2-idle-point detector. A state machine 42 always forwards the data to a 128×3-bit buffer 44 . The uncoded 8-bit data is also sent to a 128×8-bit buffer 46 . From buffer 44 , the data is sent to a control & read-address generator 48 , and then to an FEC 50 (where SOF, SOP, and EOP stand for start-of-frame, start-of-parity, and end-of-parity, respectively). A 7-bit next T_FEC 52 serves to hold the positions of the T_FEC symbol sets in the FIFO when the symbol sets are matched in the “data_state” (listed below) for the T_FEC symbol set on-line, so that when the final T_FEC O symbol set arrives, the value held in next T_FEC 52 is the former T_FEC symbol set, which indicates the end of the data-frame position. Seven bits (i.e. log 2 (128)) are needed to provide the place for the 128-byte FIFO. Two values are held for the match of the T_FEC_O symbol set and the T_FEC_E symbol set. Another symbol set is held for the next short packet, which can arrive while the current packet is being processed (i.e. sending the parity bytes out).
The various states and state instruction-sets of state machine 42 are defined as follows:
Idle_state:
waiting for S_FEC detection; (1)
if S_FEC detected; (2)
then go to Start_state; (3)
Start_state:
SOP bit=1; (4)
go to Data_state; (5)
length=0;block=1; (6)
block_length=0; (7)
Data_state: (increment distance)
length=length+1; (8)
block_length=block_length+1; (9)
if block_length>(239+16); (10)
then block_length=0; and (11)
block=block+1; (12)
check for T_FEC_E and T_FEC_O; (13)
put the minimal distance in the buffer according to whether the match is even or odd; (14)
check for 2 idle-points; (15)
if the minimal distance corresponds to T_FEC_E and idle-points≦4; (16)
then go to Temp_end_state; (17)
Temp_end_state: (defined not to consume clock cycle)
old_check=read (FIFO_status of current place)−16*(block)+6; (18)
if (the minimal distance of old_check)+(current minimal distance)≦4; (19)
then go to End_state; (20)
else go to Data_state; (21)
End_state:
SOP of FIFO_data (16*(block)+6+even/odd)=1; (22)
EOP=1; (23)
go to Idle_state. (24)
The weighted-correlation method keeps the same correlators as described in the analysis above. The method involves different weighting of errors in bit-positions where the near legal codewords are closer in hamming distance. The legal codewords, which are neighbors of the received codeword, are distanced from the received codeword differently. There are specific positions for which the codewords are closer and the probability of a single error in such positions can cause an error in the word detection. If a single error, which occurs at one of these positions is specifically checked and not in every bit in the sequence, then the ( 60 4 ) factor is reduced, since only four specific positions are checked, not every combination out of the 60 bits.
The positions are checked by weighting the position bit errors and checking for larger hamming distances. Weighting is performed once at a symbol to indicate single-error weighting. Higher hamming distances are assigned to specific bit errors. For example, at the first −T symbol, when there is a single error in bits 4 , 8 , and 9 (i.e. a legal codeword is found in a bit difference of bit 4 or bit 8 or bit 9 ), a weighting distance of two bits is assigned for this error. At the second −R symbol, when there is a single error in bits 8 and 9 (i.e. a legal codeword is found in a bit difference of bit 8 or bit 9 ), a weighting distance of two bits is assigned for this error. A preferred embodiment of the present invention allows a single bit error in the first −T symbol with an additional check of the disparity of the correlator, assuming that the codeword erroneously having the T symbol arrives from the same disparity correlator for T symbol and that the codeword is verified.
Within the weighted-correlation method, there are two parameters that affect performance: false detection and misdetection, False detection utilizes random data detection as a good correlator. Misdetection results in a good correlator being missed due to errors. There is tradeoff between the two parameters of improving one occurs typically at the “expense” of degrading the other. The weighted-correlation method can be embodied in a device similar to the correlator state machine of FIG. 2 .
Another novel feature of the weighted-correlation method is that the method defines different decision threshold based on the detected errors. For achieving <10 −12 random data protection, at least three errors are needed to occur in the data stream before declaring a “pass” state. For achieving <10 −12 misdetection protection, at least three errors are needed to occur in the data stream before declaring a “fail” state.
Therefore, the maximum hamming distance for weighted two-bit errors is eight because it is undesirable if two errors, in which each error is weighted by two bits, will cause misdetection. Such a situation arises in the case of weight of five bits, in which each error is weighted by two bits. In such a case, two error bits occur. For other errors, the hamming distance can be smaller than six because three errors can cause misdetection. In order to improve performance, errors in the last two symbols would decrease the threshold because those symbols allow distances of two to other valid symbols.
Weighting specific error positions can increase the performance of the correlator for misdetection, thereby reducing the ( 60 4 ) component. The enhancement in performance, as mentioned above, is due to the fact that a single error can occur in the 10-bit symbols only at specific positions for valid codewords. If a single error at such a position is specifically checked, then the ( 60 4 ) component is reduced, since four specific positions are checked.
The justification for such an approach is that the probability of a single error is much higher than all combinations of possible double errors. This assumption is not valid when the BER is high. When the BER is low, then the weight can be increased. For a BER of 10 −4 , a weight of two is adequate (i.e. 10 −4 compared to ( 10 2 )*10 −8 ). Since the hamming distance is six and there are 1800 codewords distanced in six bits, the weighting will not reduce all combinations. Only single-error combinations can be reduced, which leaves some “error factor” for the double-error case.
As an example for the T_FEC_O symbol set (i.e. T/R/R/K28.5/D/T/R) and T_FEC_E symbol set (i.e. T/R/K28.5/D/T/R), which refer to the specific correlators of the IEEE802.3 clause 65 FEC correlators, an analysis is presented on T_FEC_E with negative disparity. The same approach is applied for the rest of the correlators (e.g. −T_FEC_E=−T/−R/−K28.5/+D29.5/−T/−R−). Disparity ruling of the false detection symbol reduces the resulting table to the following relevant sequences:
+ T _FEC — E+T/+R/+K 28.5/− D 10.1/− T/−R−; (1)
− T _FEC — O=−T/−R/−R/−K 28.5/+ D 16.2/− T/−R −; and (2)
+ T _FEC — O+T/+R/+R/+K 28.5/− D 5.6/− T/−R −). (3)
Table 1 shows the single-bit-error codewords for the indicated symbols.
TABLE 1
Single-bit-error codewords for the indicated symbols.
−T
−R
−K28.5
+T
+R
+K28.5
−, D29.1,
−, D23.1,
−, D12.5,
+, D29.6,
+, D23.6,
−, D19.2,
+bit 9
+bit 9
−bit 4
−bit 9
−bit 9
−bit 4
−, D29.5,
−, D23.5,
−, D20.5,
+, D29.2,
+, D23.2,
−, D11.2,
+bit 8
+bit 8
−bit 3
−bit 8
−bit 8
−bit 3
+, D13.7,
−, D28.5,
−, D18.7,
−, D3.2,
−bit 4
−bit 5
+bit 4
−bit 5
+, D7.5,
−, D7.2,
+bit 2
−bit 2
+, D12.5,
+, D19.2,
+bit 4
+bit 4
+, D20.5,
+, D11.2,
+bit 3
+bit 3
+, D28.5,
+, D3.2,
+bit 5
+bit 5
The following correlation check is relevant for five distant codewords in which two errors are allowed and three errors cause a misdetection. The decoder counts the errors in the correlator sequence. At the first −T symbol having an error in bits 4 , 8 , and 9 , a weighting of two bits is assigned to an error in these positions. At the second −R symbol having an error in bits 8 and 9 , a weighting of two bits is assigned to an error at these positions. The process is applied to the other symbols in a similar fashion.
In the highest probability case, for a single error having a hamming distance of less than six, the probability of misdetection is less than 3×2×4×(10 −4 ) 3 =2.4×10 −11 . In the case of six allowable errors, the total error is composed of single errors plus one double-error. This case applies for configurations in which three errors are allowed and four errors cause a misdetection. Single errors are weighted by two. The hamming distance is less than eight if all of the errors are single error in the weighted bits. The hamming distance is less than six if there is an error in the non-weighted bits of the last two symbols. The probability of misdetection is less than:
(3×4×3×2+1×4×3×2+1×3×3×2+1×3×4×2+1×3×4×3+( 10 2 )×(1×3+1×4+1×3+1×2+2×4+3×3+3×2+4×3+4×2+3×2))×(10 −4 ) 4 =2.9×10 −13 .
A schematic overview of the methods are shown in FIGS. 3-7 . FIG. 3 is a high-level flowchart of the processing steps in the double-correlation method, according to the present invention. After pre-processing of the FEC data frame has been done (Step 60 ), the double-correlation is performed (Step 62 ) and the frame boundary determined (Step 64 ). FIG. 4 is a high-level flowchart of the processing steps in the weighted-correlation method, according to the present invention. After pre-processing of the FEC data frame has been done (Step 60 ), the weighted-correlation is performed (Step 66 ), the weighted correlation is compared to the threshold (Step 68 ), and the frame boundary determined (Step 70 ). FIG. 5 is a high-level flowchart of typical pre-processing steps in prior-art methods. The pre-processing of the frame (Step 60 in FIGS. 3 and 4 ) typically includes checking correlators with symbol sets (Step 72 ), obtaining hamming distances from a correlation sequence (Step 74 ), and comparing the hamming distances (Step 76 ), for example.
FIG. 6 is a schematic flowchart of the processing steps in a multiple-correlation method, according to the present invention. FIG. 6 shows the processing steps in greater detail. After the first correlator has been checked for a match and the hamming distance has been calculated (Step 80 ), the 2 nd through the N th correlators are checked for a match and the hamming distance are calculated (Step 82 ). Step 82 refers to the more general case of multiple-correlation. For the double-correlation method described above, the process continues after the second correlator is checked. The first threshold is then checked for a match (Step 84 ). If there is no match, the correlators are checked again (Step 80 ). If there is a match, the 2 nd through N th thresholds are then checked for a match (Step 86 ). If there is no match, the correlators are checked again (Step 80 ). If there is a match, a decision is made on the correlation of the frame (e.g. start_of_packet, end_of_packet, end_of_parity) (Step 88 ).
FIG. 7 is a schematic flowchart of the processing steps in the weighted-correlation method, according to the present invention. FIG. 7 shows the processing steps in greater detail. After the correlator has been checked for a match and the hamming distance has been calculated (Step 90 ), the hamming distance is weighted according to a parameter set (Step 92 ). Based on the parameter set, the hamming distance may or may not be weighted. If the hamming distance is not weighted, the first threshold is checked for a match (Step 94 ). If there is no match, the correlator is checked again (Step 90 ). If there is a match, a decision is made on the correlation of the frame (e.g. start_of_packet, end_of_packet, end_of_parity) (Step 100 ). If the hamming distance is weighted, the 2 nd through N th thresholds are checked for a match (Step 96 ). Step 96 utilizes the weighted correlation, and refers to the more general case of multiple weighting. If there is no match, the correlator is checked again (Step 90 ). If there is a match, the weighted correlation is compared (Step 98 ), and a decision is made on the correlation of the frame (e.g. start_of_packet, end_of_packet, end_of_parity) (Step 100 ). It is noted that the weighting correlation method can be generalized to include multiple thresholds by iterating Step 96 .
In other preferred embodiments of the present invention, both the double-correlation state-machine method and the weighted-correlation method can include the option of performing the correction with an additional decoding of the FEC code in order to check if the number of errors is high. In such embodiments, the FEC BER is compared, in addition to the weighting or state-machine check, to an FEC BER threshold. In such a scenario, the correlators are protected by the FEC code, and additional protection for the correlator detection is provided. Furthermore, it is noted that the double-correlation method can be extended to a multiple-correlation method by following the scheme detailed above with additional correlation between correlators and symbol sets.
It is appreciated that the weighted-correlation method described above is not limited to the parameter sets mentioned, used as examples, for weighting hamming-distance indicators. Such alternate parameter sets can be based on, for example, on-line metrics or a priori knowledge of previous symbol sets.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications, and other applications of the invention may be made.
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The present invention discloses devices and methods for improving data correlation using a multiple-correlation state-machine, the method including the steps of: (a) pre-processing a data frame having a plurality of symbol sets, wherein each symbol set demarks a respective frame field of the frame, to provide a threshold-compared hamming-distance indicator; (b) comparing the threshold-compared hamming-distance indicator with at least one multiple-correlation threshold to provide a threshold-compared multiple-correlation indicator; and (c) combining the threshold-compared hamming-distance indicator and the threshold-compared multiple-correlation indicator to determine a match/no-match comparison indicative of the respective frame field. In some embodiments, the step of combining includes forming a logical-AND of the threshold-compared hamming-distance indicator and the threshold-compared multiple-correlation indicator. Preferably, the method further includes the step of: (d) prior to the step of combining, comparing a BER of the frame to a BER threshold. Also disclosed is a weighted-correlation method for improving data correlation.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This is a Continuation Application of U.S. Ser. No. 12/467,160 filed May 15, 2009, now issued U.S. Pat. No. 8,356,916, issued Jan. 22, 2013, which application claims priority under 35 U.S.C. §119 of provisional U.S. applications 61/054,089 filed May 16, 2008 and 61/097,483 filed Sep. 16, 2008, all of which applications are hereby incorporated by reference in their entireties.
BACKGROUND OF INVENTION
Embodiments of the present invention generally relate to systems and methods for lighting. In particular, embodiments of the present invention relate to systems, methods, and apparatus for highly controlled light distribution from a light fixture using multiple light sources, such as LEDs (light emitting diodes).
Existing HID fixtures use single large light sources which provide light beams which can be controlled somewhat by varying reflector design and mounting orientation. Typical LED fixtures having multiple small light sources function similarly. Each small light source has an optic (reflective or refractive lens) which creates a particular beam pattern. The beams from each LED are identical in size, shape, and cover the same area (the offset of a few inches based on position within the fixture is insignificant given the size of the beam as projected). This means that the beam from the fixture is simply a brighter version of a single beam.
This approach requires the optic being used with the LED be designed to produce the final shape of the luminaire output (for example an IES type II distribution) when combined with the LED. The disadvantage of this approach is that the designed optic can only be used for one type of distribution and requires separate development, tooling, and inventory control for each optic and beam type. An example of these types of fixtures are the LED fixtures produced by BetaLED (Beta Lighting Inc., Sturtevant, Wis.; www.betaled.com) which use an array of identical “Nanoptic”™ lens which are designed for each different type of beam desired.
Thus, these fixtures may be improved with regard to controlling the distribution and intensity of the beam, and control of glare and spill light. A light fixture which provides a beam pattern that is more easily varied and controlled is therefore useful and desirable in the lighting industry.
SUMMARY OF THE INVENTION
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
Embodiments of the present invention are described with reference to LEDs, LED lighting, etc., however, embodiments of the present invention are equally applicable to various other solid state (also referred to as solid-state) or other lighting devices (such as e.g., lasers) or fixtures that allow for multiple light sources to be packaged together in a small area.
For purposes of description it is convenient to describe the embodiments wherein the LEDs are facing up. For purposes of description of the composite beam output, it is convenient to describe the apparatus wherein the LEDs are facing down. Descriptions in terms of directional orientation is not intended to preclude mounting in any other orientation as desired.
It is therefore a principle object, feature, advantage, or aspect of the present invention to improve over the state of the art.
It is a further object, feature, advantage, or aspect of the present invention to solve problems and deficiencies in the state of the art.
Further objects, features, advantages, or aspects of the present invention include a method for creating a system of light distribution to provide lighting of a specified illumination to a pre-determined area. Said area can include standard beam shapes such as IES/NEMA beam types as well as individually customized beam shapes, including shapes having uneven light distribution with added or subtracted amounts of light in small areas which can be on the order of one meter square. One example, the composite beam, e.g. beam 200 as seen in simplified form from above in FIG. 2A , can be comprised of light beams 210 from a single fixture 10 . Alternatively, the composite beam 220 may be formed from light beams 210 from multiple fixtures 10 that are part of a collective group (as seen in FIG. 2B ). IES or IESNA (Illuminating Engineering Society of North America) and NEMA (National Electrical Manufacturers Association), and standard beam shapes are well-known to those skilled in the art.
Advantages of some embodiments include the ability to provide illumination of the desired shape, size and intensity to target areas of a pre-determined specification, such as corners, walkways, building surfaces, as well as areas in proximity to “low light zones” such as residences, parks, etc., using relatively high intensity (high candela produced), high efficiency (high lumens/watt) light sources. Other advantages include the ability to provide an even illumination of a target area that avoids harsh spots, shadows, glare, and other undesirable effects.
Further objects, features, advantages, or aspects of the present invention include an apparatus, method, or system of lighting units comprising a plurality of lighting elements, such as one or more LEDs, each element having an associated optic which is individually positionable. In embodiments of the present invention, one or more optics are developed using optimization techniques that allow for lighting different target areas in an effective manner by rotating or otherwise positioning the optics to create a composite beam. Associated optics may include reflectors, refractive lenses, TIR lenses, or other lens types. The determination of which type of associated optics to use can be based on applicability to a particular use such as emittance angle from the fixture, or manufacturing costs and preferences, for example.
Further objects, features, advantages, or aspects of the present invention include an apparatus, method, or system of lighting which makes it possible to widely vary the types of beams from an available fixture using a small number of inventoried optics and fixtures, thereby potentially reducing fixture cost, reducing lead time for custom lighting, and multiplying the versatility of any new fixtures or optics which could be created. In some cases, by using a combination of individual beam patterns, a small set of individual optics (perhaps on the order of less than 10) would be sufficient to create a majority of the typical and specialized composite beams needed to meet the needs of most lighting projects and target areas.
Apparatus
Some embodiments of the present invention provide for an apparatus comprising a lighting fixture with a plurality of individual light sources. The plurality of individual light sources may include solid-state light sources (such as LEDs). Each light source may include its own optic with elements such as reflectors, refractive lenses, light blocking tabs, and/or other elements. Each individual optic, according to embodiments of the present invention, is part of an array of optics placed in a specific location relative to the fixture and/or the other light sources. This array could be an arrangement of rows, a circular, radial, spiral pattern or any other pattern or shape. The individual optics could be mounted in the fixture by a means that also provides for adjustment in one or more directions relative to the light sources so as to vary the location of the individual beam within the composite beam. Adjustment of the optics could be preset by the manufacturing or assembly process, or the fixture could be manufactured such that the rotational position of individual optics could be set at installation or at a later time. This could allow, for example, a local inventory of individual fixtures that could be very quickly configured for given applications.
While traditional LED fixtures commonly mount the LEDs with snap-fit components and/or adhesives, these mounting techniques can lead to loss of position or alignment, or fixture failure within a short period of time relative to desired lifetime of area lighting fixtures (i.e., a few years vs. a desired lifetime on the order of decades). The envisioned mounting/adjustment method and apparatus provide improvements in the art.
According to embodiments of the present invention, the fixture may include LEDs mounted on a substrate that may be a circuit board of laminated or layered metal, standard circuit board materials, and/or other materials that provide dimensional stability, a means to provide or affix necessary circuitry, and optional benefits for thermal management.
In embodiments of the present invention, the fixture may optionally include elements to further direct or control the individual beams such as tabs (e.g. 35 . FIG. 9 ) or analogous structure which may be affixed within the fixture relative to one or more individual light sources and placed in such a way as to restrict direct, non-reflected or non-controlled light or similarly to restrict light emitted at an angle which is not desired for the particular application.
System
Embodiments of the present invention provide for a system that uses a plurality of fixtures or fixture groups placed at various spaced-apart locations within or around an area to be lighted. Further, embodiments of the present invention can use one or more groups with one or more fixtures per group to provide a desired level of illumination within a target area of a pre-determined specification in order to provide coordinated benefits of the above lighting method for areas such as sports fields, parking lots, buildings, etc.
Method of Designing Lighting System
According to embodiments of the present invention, designing the lighting system may require two or three separate steps, including analyzing the intended application, selecting individual optics, and designing the composite beam. These steps may be repeated as necessary to optimize the design.
a) Creating Composite Beam
In one aspect, the beam is composed as follows: the light beam from each optic (i.e. the beam produce by light from a light source which is directed by the optic) produces a portion of the overall beam pattern. This beam portion may be the primary or essentially the only light source for a certain portion of the target; alternatively, by combining a set of these optics that project various beam types (for instance circular, elongated, or oblong beams), a series of overlapping beams can be built to a desired pattern (e.g. FIG. 3D ) at a desired level of illumination, which can help to compensate for the distance (inverse square law) and incident angle (cosine law) or for other factors. For example, more individual beams can be directed towards the farther edges of the composite beam (see e.g. FIG. 3B ), or different beam patterns (e.g. circular, elongated, narrow, wide, etc.) having different intensities can be created such that distribution in the target area is even (e.g. many ‘ten degree’ circular beams might be used for illuminating the area farthest from the fixture, while fewer ‘twenty degree’ beams could be used closer to the fixture and so on). The beam edges may overlap the adjoining beam at any desired degree to provide uniform distribution or the entire beam may overlap another beam to increase the intensity, and the composite beam can be composed of a combination of a number of individual beams of different sizes, shapes, distribution angles, and orientations (e.g. subject only to available lens design, an “oblong” beam 403 FIG. 4 could be oriented axially with the beam, transverse to the beam, or at some other angular orientation relative to the beam axis). The result would be a beam distribution, in a rectangle, oblong, oval, circle, fan, or other shape as desired as illustrated in FIGS. 3A-3E .
In accordance with embodiments, as might be used on a sports field, such a beam could provide illumination at, for example, the base of the light fixture mounting pole as well as to distant areas on a field. Additionally, in embodiments of the present invention, the beam could be cut off at the edge of a field ( FIG. 3C ) while still providing adequate illumination close to the edge of the field. Examples of shapes which can be easily adapted to illuminate, for example, the corner of a field ( FIG. 3E ), a football field (see FIG. 3D ), a short and wide building 270 (see FIGS. 14A-C ), a tall and narrow building 280 (see FIGS. 15A-15B ), as well as many other specific shapes and configurations are shown.
‘Pixellation’
Unlike conventional lighting fixtures, embodiments of the present invention can provide ‘granular’ or ‘pixellated’ control of light at a high level of precision, wherein for a given application, small areas, which could be on the order of 1 square meter (more or less according to lens design, mounting height, fixture mounting angle, etc.), can have brightness somewhat controlled. This allows areas within the target area to be emphasized. For buildings, signs, or other applications where a sharply defined shape is to be illuminated, these embodiments provide greater flexibility than conventional lighting.
In an example, an HID lamp putting out 36 , 000 lumens can cover approximately 180 m 2 (an area 12 m×15 m) at 200 lux (lumens/m 2 ). Embodiments of the present invention provide for a fixture that includes multiple LEDs that can cover the same 180 m 2 area. Each single LED, in one example, is capable of putting out 200 lumens and provides enough light for one square meter. This provides a level of precise control that provides, in effect, a “pixel by pixel” control of illumination on a target area, which both conventional HID and LED lighting cannot do. Both conventional HID and conventional LED fixtures are limited to the beam pattern as projected from the fixture, with minor modification possible by use of methods which can only affect the whole beam or a large portion of the beam.
Additional Optional Elements
An embodiment that uses reflective-type lenses might not work well if a flat plate glass cover, e.g. 40 , FIG. 1B , were required for the fixture and the fixture needed to be oriented more or less parallel to the ground, since some beam patterns might require a high angle of incidence. The result might be that the light might be reflected by the surface of the cover rather than transmitted through the cover. In this case, it might be more effective to use the refractive lens design or to change the cover design. Use of anti-reflective coatings for covers is well known in the art, with theoretical allowable angles of incidence up to 60° from normal, which could increase usability of refractive lenses at higher angles. However, their use is generally limited to about 45 degrees from normal, which could make the use of refractive lens arrays rather than reflective arrays more effective under some circumstances.
Optional additional elements could include an additional lens or lenses or other optical element in association with the fixture which may contribute to the overall lighting effect or may provide other benefits such as enhanced aesthetics, protection of the components of the fixture, or reducing any unpleasant visual effects of directly viewing the fixture.
A fixture using an array of LEDs could allow light at an angle which is relatively controlled and that might be acceptable for some applications but could still benefit from additional control. Using a single visor of a type which is common to existing lighting fixtures would tend to either completely block the light emitted from the lights near the front of the fixture (refer to FIG. 7B ) or to have little or no effect on the angle of emission from the light sources near the rear of the fixture. (refer to FIG. 7C ). Multiple visors 797 as shown in FIG. 7D would provide an additional novel means of precisely controlling light from a fixture.
Aimability
Some embodiments of the invention provide or enhance the ability to pre-aim a fixture at the factory relative to a particular location or application. The envisioned embodiments may be easily pre-aimed, since their placement of light on an area can be accurately established and indexed to the intended mounting positions of the fixtures. Additionally, the fixtures may be aimed precisely in the field by indexing from individually aimed lights/optics or from precision manufactured reference location on the fixture.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments and aspects of the present invention will be described and explained through the use of the accompanying drawings in which:
FIGS. 1A-1B illustrate a fixture according to embodiments of the present invention;
FIG. 1C illustrates a fixture according to embodiments of the present invention;
FIG. 1D illustrates a substructure or frame which provides orientation and indexing according to embodiments of the present invention;
FIG. 1E illustrates a method of assembly of an array of LEDs and optics according to embodiments of the present invention;
FIGS. 2A-2B show aspects of formation of a composite beam according to embodiments of the present invention;
FIGS. 3A-3E illustrate potential composite beam layouts according to embodiments of the present invention;
FIG. 4 shows examples of some beam shapes that may be created or used as sub-beams according to embodiments of the present invention;
FIG. 5 illustrates aspects of an example fixture using reflector type optics according to embodiments of the present invention;
FIG. 6A shows Bezier controls used in the design of a reflective optic element according to embodiments of the present invention;
FIG. 6B is a graphical representation of an untrimmed image of an optic created according to embodiments of the present invention;
FIG. 6C is a graphical illustration of the trimmed image based on the trim line of an optic according to embodiments of the present invention;
FIG. 6D shows isocandela traces based on a typical parabolic reflective optic element;
FIG. 6E shows footcandle traces based on a typical parabolic reflective optic element;
FIG. 6F shows isocandela traces based on a modified reflective optic element created according to embodiments of the present invention;
FIG. 6G shows footcandle traces based on a modified reflective optic element created according to embodiments of the present invention;
FIGS. 7A-7D illustrate the need for and application of a ‘visor’ according to embodiments of the present invention;
FIGS. 8A-8B illustrate and application of the ‘visor’ to arrays of LEDs according to embodiments of the present invention;
FIG. 8C illustrates a section view (with some lines removed) of a fixture according to embodiments of the present invention having ‘visors’ applied to arrays of LEDs according to embodiments of the present invention;
FIG. 9 illustrates an application of a reflective tab to an array of LEDs according to embodiments of the present invention;
FIG. 10 illustrates a means of adjustment of an optic according to embodiments of the present invention;
FIGS. 11A-11B illustrate differences in the effect of lighting with and without control of spill light;
FIGS. 12A-12C illustrate a composite beam with a relatively narrow beam and large incident angle according to embodiments of the present invention;
FIGS. 13A-13C illustrate a composite beam with a wide beam which projects light from a low to high range of incident angles according to embodiments of the present invention;
FIGS. 14A-14C illustrate another building type that might be illuminated by a fixture in accordance with embodiments of the present invention;
FIGS. 15A-15B illustrate how a fixture, in accordance with embodiments of the present invention can provide precise illumination on the face of a tall, narrow building. For comparison, a conventional fixture with a conventional round beam on a tall, narrow building is shown in FIG. 15C ;
FIGS. 16A-D are similar to FIGS. 14A and B and showing how a beam that could be suitable for a wide building could be modified to be suitable for a narrow building.
The figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be expanded or reduced to help improve the understanding of the embodiments of the present invention. Moreover, while the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the figures and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
Embodiments of the present invention provide for an apparatus, system, and method for creating a composite beam from LEDs (or other individual light sources) and associated optics such as reflectors or lenses. The composite beam can be comprised of light beams from a single fixture (see FIG. 2A ), or light beams from light sources of multiple fixtures that are part of a collective group (see FIG. 2B ). Said fixture contains a plurality, which may be a large plurality, of individual light sources 20 , FIG. 1A and their associated optics. Associated optics may include reflectors 30 , FIG. 1A , refractive lenses 60 FIG. 1C , TIR lenses 50 FIG. 1C , or other lens types. The determination of which type of associated optics elements to use can be based on applicability to a particular use, which can include considerations of type and shape of fixture (e.g. in order to consider such things as wind loading and aesthetics), mounting angle, ambient conditions, etc.
A. Exemplary Method for Designing a Lighting System—Overview
In general, the lighting professional using embodiments of the present invention will first analyze the intended application, then, select individual optics, and design the composite beam. Of course this process may be iterative given possible design conditions and constraints.
Analyzing the Application
In analyzing the application, a determination will be made regarding the size and shape of the intended target area and desired illumination level based on intended usage, yielding a total desired lumens value or figure. Then a determination of the minimum number of fixtures of the type anticipated to be used can be made, based on the number of lumens per light source and number of light sources per fixture which must provide the required total lumens. These values, parameters, or figures will then be modified, based on requirements for the target area, such as e.g. preferred, allowable, and prohibited fixture mounting locations, fixture setback from the target area, mounting height, calculations of angle of incidence of the illumination and consideration of the inverse square law of optics. Given these items, using one of several possible methods, the lighting designer will begin designing the light layout to provide desired illumination of the target area. This will be similar to designing using conventional HID or LED fixtures. However, the designer can plan lighting at a much finer scale since the individual light sources each contribute a small amount to the total light applied to the entire target area. Additionally, unlike using conventional HID or LED lighting, if there are any areas for which the amount of light should be increased or reduced, this can be accomplished by changing the aiming of a few individual light sources without necessitating a significant reduction or increase in light on adjacent areas.
a) Select or Design Individual Optic
If satisfactory individual optics for the given application are already in existence, one or more types may be selected to potentially meet the needs of the application which has been previously analyzed. If not available from previous design, new ones may be designed. One method that may be used according to embodiments of the present invention is discussed later.
One advantage of the present invention is that a single optic, or limited number of optics, can be used to create multiple lighting configurations. This is done by creating an optic that creates a portion of a beam pattern that can be used with an LED or similar light in an array of similar lights to create the desired final beam pattern shape from the luminaire (e.g. IES type V). The desired final beam pattern is created using the aforementioned designed optic with an LED array and positioning the optic at various angles to the LED to create the final beam pattern using the sub-pattern from each optic. FIG. 2A illustrates an example of a composite beam 200 formed by sub-beams 210 .
While embodiments of the present invention can be used for creating area lights having patterns as prescribed by the IES types, the pattern from the luminaire is not constrained to the IES types and can be used to custom configure a luminaire for a specific lighting task.
Select or Design Fixtures
Within the design process, individual fixtures will be selected for use with the appropriate optics. These fixtures will be placed in groups on poles or in mounting locations according to the overall plan for the application. At this point the original design considerations and selection of optics will be re-examined and changes made as necessary to fine-tune the design.
B. Detailed Development of Optics
Deficiencies of Parabolic Optics
The development of the optic for the sub-beam is now described according to certain aspects of the invention. While a parabolic optic is easily designed and may be used in embodiments of the invention, other types of optics can provide more desirable results. It is well known that a parabolic surface when combined with a light source at the parabolic focus produces a spot beam that is aimed along the axis of the parabola. This spot beam can be directed by pointing the parabolic axis in the desired direction. However, one disadvantage of the spot beam from the parabola for area illumination is that the intensity profile from the reflector will create a non-uniform distribution on the area being illuminated, with an intense spot in the center with a sharp transition to zero light on the edge. This is ordinarily not an optimum output beam for use in illuminating areas. A desirable pattern usually contains a more uniform distribution with light directly below the luminaire smoothly transitioning to the edge of the beam.
Embodiments of the present invention provide for systems and methods for being able to develop several different beam types from a single optic design that has been specially designed to allow for the smooth blending of a sub-beam into a composite beam. This is accomplished with a single optic rather than multiple optics, a single development cycle, and a single piece to inventory, resulting in distinct advantages in cost and speed to market.
Embodiments of the present invention provide for creating a modified parabolic shape to produce an output beam that both projects a spot to be used as a sub-beam, and creates a smooth distribution on the area being illuminated in order to have sub-beams that can be combined to create desirable illumination beams from the full luminaire. An example angular output for a parabolic optic pointed at 70° to nadir and a CREE (Durham, N.C. USA) model XRE White LED is shown in the graph in FIG. 6D (units are candela), which illustrates a characteristic “spot” type beam from the system. Taking this beam and using it to illuminate a plane 10 feet below the system as an area type light yields the distribution on the ground is shown in FIG. 6E (units for the output are footcandles).
Modifying Parabolic Optics
An example starting point with Bezier control points 600 is shown in FIG. 6A . Each control point is parameterized via its X,Y,Z coordinate and its control point weight W. The basic parabola shape produces a spot beam.
The parabolic shape is parameterized using a Bezier polynomial scheme to allow for adjustment of several parameters to control the reflector shape to achieve a desired output distribution. Bezier mathematics are used extensively in computer aided design and are known to those skilled in the art. The result of using Bezier mathematics is a simplified list of points and control points that generally describe the surface and allow for manipulation of the surface through these parameters. The use of Bezier splines for optical design is well documented.
The parameterized parabola is redefined using an automated optimization routine to drive the reflector shape to produce a sub-beam that will produce a more uniform output beam when arranged as with the parabola spot beams above. The optimization routine is a genetic algorithm (see, e.g., Vose, Michael D (1999), The Simple Genetic Algorithm: Foundations and Theory , MIT Press, Cambridge, Mass. Whitley, D. (1994); and A Genetic Algorithm Tutorial . Statistics and Computing 4, 65-85). A genetic algorithm can be beneficial in solving these types of problems due to the large number of variables and the uncertain behavior of the merit function. The genetic algorithm used may include real valued chromosomes along with tournament selection, crossover, and mutation. Other variations of genetic algorithms can be used as required. The merit function in at least one embodiment is defined as the falloff of illumination from the center of the pattern to the edge of the pattern. The value of the merit function was increased as this falloff became closer to a linear falloff. Of course, depending on the desired use, the merit function would be different for different applications. The merit function is well-known (see, e.g., Press, W. H.; Flannery, B. P.; Teukolsky, S. A.; and Vetterling, W. T. “Bessel Functions of Fractional Order, Airy Functions, Spherical Bessel Functions.” §6.7 in Numerical Recipes in FORTRAN: The Art of Scientific Computing, 2 nd ed . Cambridge, England: Cambridge University Press, 1992).
Table 1.0 shows the surface definition of an optic that was created using this merit function. The optic is defined by the 3rd Degree×3rd Degree Bezier Patch (see, e.g., U.S. Pat. No. 5,253,336 regarding 3 rd Degree Bezier Patch) Description:
TABLE 1.0
Surface Definition
Pt #
X
Y
Z
Weight
1
9.52
7.88
−0.79
1.000
2
11.59
6.18
5.97
1.547
3
7.82
4.74
13.22
2.368
4
6.84
−0.04
−0.46
1.296
5
9.70
1.83
3.48
2.968
6
5.43
3.48
10.46
3.859
7
3.61
−4.24
−0.15
0.739
8
5.28
−0.96
4.98
1.846
9
3.19
1.34
9.22
0.771
10
0.00
−2.63
0.00
1.000
11
0.00
−2.60
6.91
2.113
12
0.00
0.67
9.27
0.727
13
0.00
4.57
11.53
1.000
Note that only the right half control points are listed as the left half is symmetric about y axis. FIG. 6B is a graphical representation of the untrimmed image (showing control points on both halves), while FIG. 6C is a graphical illustration of the trimmed image based on the trim line described in Table 2.0.
TABLE 2.0
Trim Line for Notch
Pt #
X
Y
Z
1
0
0.54
0
2
0.213
0.54
0
3
2.647
4.645
0
After optimization of the shape, the sub-beam has the following angular and illumination outputs as shown in FIGS. 6F and 6G . When the optics are subsequently arranged by rotation around the LEDs to achieve a specific pattern, the resulting output pattern is a more desirable illumination.
Exemplary Genetic Programming Algorithm
In embodiments of the genetic algorithm, the variables that are manipulated are the X,Y, and Z coordinates of each control point, along with the Bezier Weight of each control point (see, e.g., Xiaogang Jin and Chiew-Lan Tai, Analytical methods for polynomial weighted convolution surfaces with various kernels , Computers & Graphics, Volume 26, Issue 3, June 2002, Pages 437-447). For the specific example, there were 36 variables. The merit function was determined by taking a slice through the illuminance data from a single reflector starting at 5 feet from the fixture out to 50 feet from the fixture. The data was taken in 1 foot increments, and then compared to a theoretical uniform line through those same points. The deviation from the line at each point was calculated and squared, and the total difference was the square root of the sum of those squares. The fitness function for the algorithm has to actually increase to show better performance, so the final merit value was 1/(total difference) so that it would approach infinity as the fit to the line got better. The actual code to calculate the fitness is shown here:
M1=0
$DO 5 50
{
VALUE ? 0 P1
M1=M1+((−0.0356*(?)+4.4778)−P1){circumflex over ( )}2
}
RETURN
LINEDIF=SQRT(M1)
FITNESS=1/LINEDIF
In the specific example, a real valued chromosome was used (in other words, the variables were not converted into zeros and ones) with 36 Genes (the total number of variables). The population size was set to 100. A tournament format was used to determine which chromosomes survived to be parents of the next generation and had 8 individuals compete in the tournament. The tournament selection was random. Crossover was performed using a random crossover mask where a 0 means to keep the first parents gene and 1 means to keep the second parents gene and reversed the order of parents to generate a pair of children for each pair of parents. Mutation in the children was allowed using a mutation threshold of 0.3 (30% chance of mutation) with a mutation amount limited to 37.5% the amount of mutation was chosen randomly to be between 0 and 37.5% if mutation occurred). 1000 generations for the optimization were run.
As will be appreciated by those of ordinary skill in the art, there are probably other combinations that could be used to either speed up the results or obtain higher fitness functions.
C. Exemplary Method—Creating Customized (Non-Standard) Beam Shapes
Customized Beam Principles
In accordance with embodiments of the present invention, individual optics may be designed using well-known optical principles to project a beam of a desired shape and distribution. For example, the optic can provide a type 5 lateral beam distribution with long vertical distribution, or a type 2 lateral beam distribution with short vertical distribution, or any other desired beam distributions. Design and construction methods for the optical lens and reflector are well known in the art. Fixtures which are nearly parallel to the ground which are illuminating a distant target have an emittance angle that is ‘flatter’ relative to the fixture, for which reflective optics may be more appropriate, while fixtures which oriented more vertically relative to the ground, or which are illuminating a target that is less distant or that is directly underneath have an emittance angle that is ‘steeper’ relative to the fixture, for which refractive optics may be more appropriate. However, there is considerable overlap between the alternatives and therefore choice of reflective vs. refractive would be made according to the circumstances. Alternatively, for some applications, use of both reflective and refractive optics on the same fixture might be appropriate.
Design of Composite Beam Per IESNA
Having analyzed the overall application of the light to the target area, and selected or designed the appropriate individual optics, the designer will lay out each individual optic within each fixture to design the composite beam. In order to design a specific composite beam for a given application and target area, several methods could be used which are known to those of ordinary skill in the art. A discussion of several methods can be found in the IESNA Lighting Education: Intermediate Level , New York: Illuminating Engineering Society of North America, ©1993, sections 150.5A and 150.5B.
In embodiments, light modeling can be used to select the optic design and orientation of the individual light beams to create the composite beam from the fixture. For example, selecting one or more of the beam shapes 400 - 403 shown in FIG. 4 or from other beam shapes, the lighting designer, with optional assistance from a commercially available lighting software program, can produce the desired composite beam shape and intensity. The designer can determine the number and combinations of beam patterns provided by the lenses within the fixtures. For each project, the designer can proceed to select individual fixtures which use a certain number of reflective and/or refractive lenses. As designed, the selected lenses would be assigned a position and orientation within the fixture such that light is distributed as desired on the target area. In accordance with embodiments of the present invention, special consideration can be given to edges of target areas in order to provide even lighting at the edges without excessive spill light beyond the target area.
Design of Beam by Luminaire Equivalence
Another method of designing a specific composite beam in embodiments of the present invention is calculating the “luminaire equivalence” of each individual optic combination, using existing or custom lighting design software. Using this method, each individual source is considered as a luminaire. The designer can select the optic system based on its photometric properties and place the light from each individual source onto the target area as desired. This process would be repeated until the desired composite beam shape and intensity level was achieved. In one or more embodiments, some level of automation could be added to the design process if desired.
Design of Beam by Standard Layout Tools
Another method of designing a specific composite beam in accordance with embodiments of the present invention is to use standard layout tools such as drafting board, computer-aided design software, or other tool(s) to arrange the selected beam shapes to create a composite pattern. For example, if the composite beam pattern desired looked similar to as shown in FIG. 3B then the available optics would be selected based on their distribution and intensity. These individual beams would be arranged to fill the area and multiple beams overlaid to achieve the desired intensity.
The following Table 3.0 describes the optic selection and orientation of the individual beams form the light source optics system to create a composite beam shown in FIG. 3B .
TABLE 3.0
Reflector Rotation
(0 degrees is straight
Optic type
out, 90 is left and
(see FIG. 4)
right)
400, 402
0
400, 402
7.5, −7.5
400, 402
15, −15
400, 402
22.5, −22.5
400, 402
30, −30
400, 402
37.5, −37.5
400, 402
45
400, 402
52.5
400, 402
60
400, 402
67.5, −67.5
400, 402
75, −75
400, 402
82.5, −82.5
400, 402
90, −90
401
−45
401
−52.5
401
−60
Design of Beam by Other Methods
Other methods of composite beam design are possible and considered included in this application.
In addition to designing a composite beam based on the use of a single fixture, embodiments of the present invention may use multiple fixtures to target the same or overlapping areas in order to build up intensity to desired levels based on well known principals of lighting. The composite beams from two or more fixtures would be combined to provide illumination over the entire target area.
Customized Beam Examples
The following figures illustrate various simplified composite beams in accordance with embodiments of the present invention. FIGS. 12A-C show a composite beam with a relatively narrow beam 240 and large incident angle. FIGS. 13A-C shows a composite beam 250 with a wide beam which projects light from a low to high range of incident angles. FIGS. 15A-B shows how a fixture of the type envisioned could provide precise illumination on the face of a tall narrow building. FIG. 15B illustrates a representation of how the individual beams might be combined to cover the desired areas on the building while essentially avoiding wasted or ‘spill’ light.
FIG. 15C shows a building as it might be illuminated by a conventional light fixture or an LED-type fixture with simple optics. The round beam fully illuminates the building but has significant spill light 290 . FIG. 15B shows, in simplified form, how the same building might be illuminated by the composite beam from a fixture in accordance with embodiments of the present invention. The multiple individual beams are directed so as to avoid significant spill light but to provide complete illumination of the target area.
FIGS. 14A-C illustrate another building type that might be illuminated by a fixture in accordance with embodiments of the present invention. FIGS. 16A-D show how an existing fixture that provides light beam 320 which is suitable for illuminating a wide building ( 300 ) spills over at 330 and would be unsuitable for a narrow building 310 . The beam as modified ( 340 , FIG. 16D ) illustrates how fixture 10 could be designed to provide the correct illumination for building 310 in accordance with embodiments of the present invention.
The composite beams of FIGS. 3A-E also illustrates how customized, or non-standard, composite beam shapes can be created to fit the needs of special applications. For example, the composite beam of FIG. 3E would be well suited for illumination in the corner of a target area. FIG. 3B also illustrates how the intensity in the distal portion of the beam can be increased by overlaying beams, (beam shapes 400 and 401 in this example).
D. Exemplary Apparatus—Reflective Lens Fixture
Fixture Construction
One example of a fixture 10 with individual optics is shown in FIG. 1A . The solid-state light sources 20 are mounted on a circuit board 80 , FIG. 1E , or other structure, in an offset row pattern. According to embodiments of the present invention, other patterns could also be used. Individual reflectors produce the desired beam pattern from each source and are also mounted on the circuit board, above each light source and oriented in the desired direction. The reflectors in embodiments of the present invention can be more or less specular, diffusing, and/or absorbing, depending on the desired effect.
Various methods of attaching the reflector to the circuit board, or other structure, are available in embodiments of the present invention. Examples of means for attaching the reflector include, but are not limited to, mounting as individual pieces above the light sources, mounting pins, fasteners or adhesive. An automated pick and place assembly machine can be used in embodiments of the present invention to ensure accurate placement of the reflectors and correct orientation per the lighting design. Alternatively, the reflectors can be mounted to a substructure or frame 90 , FIG. 1D-1E , which provides orientation and indexing.
Optics
The individual optic used in the fixture of FIG. 1A is a reflector ( 30 , FIG. 1C ) over the LED light source 20 which projects the light in a desired pattern, based on the reflector design. The plurality of reflectors are oriented in various directions, providing a beam pattern as illustrated in FIG. 2A as one example of a possible composite beam pattern. Orientation of each reflector is determined based on the desired beam pattern and intensity.
The reflectors can be offset from each other to avoid potentially blocking light from the light source to its rear. They can include an optional v-shaped notch in reflector 30 ( FIG. 6C and FIG. 9 ) to allow some of the light to be directed downward instead of outwardly. This provides lighting directly below or in front of the fixture. FIG. 5 illustrates an array 500 of individual light sources and examples of possible angular orientations for typical reflectors in accordance with embodiments of the present invention.
The reflector can be made of various materials depending on application, cost considerations, availability, etc. For example, a reflector could be made of molded plastic with metallized surface, injection molded, machined and polished from aluminum, etc.
An example of a type of adjustment or indexing method could be capturing the individual lenses in a circular hole which could have degree or index marks. The lenses could be equipped with a screwdriver slot and adjusted to a desired position. Or lenses could be positioned by precision equipment which is temporarily indexed to the fixture. Lenses might be held in place by a friction fit or by any number of clamping or fastening methods. The optics could also be simply positioned in a matrix 90 , FIG. 1E , using an indexing system (e.g. cut-outs 95 , spacers, bosses, etc.). Additionally, fine-tuning of light distribution could be accomplished on site, and light distribution from a fixture could be modified if needs for a specific location should change.
In accordance with some embodiments, the indexing system could be machined or manufactured automatically as part of the matrix 90 ; the array of optics can be attached such that the predetermined spacing, rotational positioning, etc. is established and maintained with reference to the individual light sources and the light fixture by using mounting pins, screws, bosses, etc. that mate precisely with indices in the mounting structure of the individual light sources (see e.g. 100 , FIG. 1E ). Further, this method of mounting could provide a high degree of accuracy in mounting over a long period of time (on the order of decades of years), and the method of mounting the optic array to the individual light sources relies on a small number of components manufactured to certain tolerances in order to ensure precise indexing of the mating components.
Further adjustments could be included as part of the system to allow adjustment in a plane that is not generally parallel to the fixture. For instance, reflectors could be adjusted by ‘tipping’ the reflector relative to the mounting plane, using trunnion-type mounts 55 with e.g. setscrew 45 or gear and sector adjustments (see FIG. 10 ). Similarly, overlays could be designed to hold the reflector at a specific ‘vertical’ angle relative to the mounting surface or template.
Example of Beam Layout
Table 4.0 describes one possible method of arranging the individual beams from the light source optics system in FIG. 5 to create a composite beam. In this example, the general composite beam is an IES type 4 shape. The reflectors in this embodiment are all parabolic but other shapes could be used. In this example, the general composite beam is produced with a common optic design, of a parabolic design, used throughout the set of light sources on the fixture 500 . See FIG. 5 for an example fixture and optical layout in reference to Table 4.0 below.
TABLE 4.0 Reflector Rotation (0 degrees is straight Source/optic X Y Z out, 90 is left and ID # (mm) (mm) (mm) right) 1 0 0 0 −90 2 28 0 0 90 3 56 0 0 −90 4 84 0 0 90 5 112 0 0 −90 6 140 0 0 90 7 168 0 0 −90 8 196 0 0 90 9 224 0 0 −90 10 252 0 0 90 11 280 0 0 −90 12 308 0 0 90 13 336 0 0 −90 14 364 0 0 90 15 0 28 0 −82.8 16 28 28 0 82.8 17 56 28 0 −82.8 18 84 28 0 82.8 19 112 28 0 −82.8 20 140 28 0 82.8 21 168 28 0 −82.8 22 196 28 0 82.8 23 224 28 0 −82.8 24 252 28 0 82.8 25 280 28 0 −82.8 26 308 28 0 82.8 27 336 28 0 −82.8 28 364 28 0 82.8 29 0 56 0 −75.6 30 28 56 0 75.6 31 56 56 0 −75.6 32 84 56 0 75.6 33 112 56 0 −75.6 34 140 56 0 75.6 35 168 56 0 −75.6 36 196 56 0 75.6 37 224 56 0 −75.6 38 252 56 0 75.6 39 280 56 0 −75.6 40 308 56 0 75.6 41 336 56 0 −75.6 42 364 56 0 75.6 43 0 84 0 −68.4 44 28 84 0 68.4 45 56 84 0 −68.4 46 84 84 0 68.4 47 112 84 0 −68.4 48 140 84 0 68.4 49 168 84 0 −68.4 50 196 84 0 68.4 51 224 84 0 −68.4 52 252 84 0 68.4 53 280 84 0 −68.4 54 308 84 0 68.4 55 336 84 0 −68.4 56 364 84 0 68.4 57 0 112 0 −61.2 58 28 112 0 61.2 59 56 112 0 −61.2 60 84 112 0 61.2 61 112 112 0 −61.2 62 140 112 0 61.2 63 168 112 0 −61.2 64 196 112 0 61.2 65 224 112 0 −61.2 66 252 112 0 61.2 67 280 112 0 −61.2 68 308 112 0 61.2 69 336 112 0 −61.2 70 364 112 0 61.2 71 0 140 0 −54 72 28 140 0 54 73 56 140 0 −54 74 84 140 0 54 75 112 140 0 −54 76 140 140 0 54 77 168 140 0 −54 78 196 140 0 54 79 224 140 0 −54 80 252 140 0 54 81 280 140 0 −54 82 308 140 0 54 83 336 140 0 −54 84 364 140 0 54 85 0 168 0 −46.8 86 28 168 0 46.8 87 56 168 0 −46.8 88 84 168 0 46.8 89 112 168 0 −46.8 90 140 168 0 46.8 91 168 168 0 −46.8 92 196 168 0 46.8 93 224 168 0 −46.8 94 252 168 0 46.8 95 280 168 0 −46.8 96 308 168 0 46.8 97 336 168 0 −46.8 98 364 168 0 46.8 99 0 196 0 −39.6 100 28 196 0 39.6 101 56 196 0 −39.6 102 84 196 0 39.6 103 112 196 0 −39.6 104 140 196 0 39.6 105 168 196 0 −39.6 106 196 196 0 39.6 107 224 196 0 −39.6 108 252 196 0 39.6 109 280 196 0 −39.6 110 308 196 0 39.6 111 336 196 0 −39.6 112 364 196 0 39.6 113 0 224 0 −32.4 114 28 224 0 32.4 115 56 224 0 −32.4 116 84 224 0 32.4 117 112 224 0 −32.4 118 140 224 0 32.4 119 168 224 0 −32.4 120 196 224 0 32.4 121 224 224 0 −32.4 122 252 224 0 32.4 123 280 224 0 −32.4 124 308 224 0 32.4 125 336 224 0 −32.4 126 364 224 0 32.4 127 0 252 0 −25.2 128 28 252 0 25.2 129 56 252 0 −25.2 130 84 252 0 25.2 131 112 252 0 −25.2 132 140 252 0 25.2 133 168 252 0 −25.2 134 196 252 0 25.2 135 224 252 0 −25.2 136 252 252 0 25.2 137 280 252 0 −25.2 138 308 252 0 25.2 139 336 252 0 −25.2 140 364 252 0 25.2 141 0 280 0 −18 142 28 280 0 18 143 56 280 0 −18 144 84 280 0 18 145 112 280 0 −18 146 140 280 0 18 147 168 280 0 −18 148 196 280 0 18 149 224 280 0 −18 150 252 280 0 18 151 280 280 0 −18 152 308 280 0 18 153 336 280 0 −18 154 364 280 0 18 155 0 308 0 −10.8 156 28 308 0 10.8 157 56 308 0 −10.8 158 84 308 0 10.8 159 112 308 0 −10.8 160 140 308 0 10.8 161 168 308 0 −10.8 162 196 308 0 10.8 163 224 308 0 −10.8 164 252 308 0 10.8 165 280 308 0 −10.8 166 308 308 0 10.8 167 336 308 0 −10.8 168 364 308 0 10.8 169 0 336 0 −3.6 170 28 336 0 3.6 171 56 336 0 −3.6 172 84 336 0 3.6 173 112 336 0 −3.6 174 140 336 0 3.6 175 168 336 0 −3.6 176 196 336 0 3.6 177 224 336 0 −3.6 178 252 336 0 3.6 179 280 336 0 −3.6 180 308 336 0 3.6 181 336 336 0 −3.6 182 364 336 0 3.6
E. Exemplary Apparatus—Refractive Lens
Optical refractive lenses 60 , or TIR lenses 50 , FIG. 1C , could be placed over the LED light sources to distribute the light, creating a similar effect, i.e. a highly controlled and customizable composite beam from a light fixture(s) with a plurality of light sources. The lenses can be made of various materials depending on application, cost considerations, availability, etc. For example, the lens could be made of molded plastic, optical glass, etc.
F. Exemplary Apparatus—Visor Strips
In embodiments of the present invention, visor strips as shown in FIGS. 8A-C and are installed in order to limit the angle of emittance from the fixture. FIG. 7 a illustrates representative light rays 760 a - c , 770 a - c , and 780 a - c emanating from light source 711 a - c in a simplified fixture 710 according to aspects of the invention. In FIG. 11A , exemplary rays 170 and 180 (composed of multiple rays 770 a - n and 780 a - n as represented in FIG. 7 a ) emanating from light fixture 10 are at an undesirable angle such that instead of illuminating tennis court 140 , FIG. 11A-B , they continue in an undesired direction 130 . Installing visor 790 as in FIG. 7 b blocks all rays 770 and 780 as desired, but also blocks ray 760 c from LED 711 c . Installing visor 790 as in FIG. 7 c does allows transmission of rays 760 a - c as desired, but also allows transmission of rays 770 a - b and 780 a - b , which is not desired. An optional solution according to embodiments of the present invention is shown in FIG. 7 d . In the embodiment shown in FIG. 7 d , installing identical visor strips 797 a - c allow rays 760 a - c to be transmitted as desired, and blocks the respective rays 770 a - c and 780 a - c from their undesired paths and redirects them to provide useable light in the target area.
These visor strips are shown in use with reflective optics, however the strips can be used with refractive or other optics in embodiments of the present invention.
The visor strips could be constructed of metal, plastic, or other materials. They can be coated with various materials to provide any type of surface desired, such as specular, diffuse, or light absorbing. The size (i.e. height), placement and angle of the visor strips could be calculated in order to provide specific benefits, such as (a) blocking light at a certain angle relative to the fixture, (b) reflecting light down as seen in FIG. 7D in order to provide additional light in a given area (e.g. directly below/in front of a mounting pole/structure). The edges of the visor strips could be linear or could be shaped or modified to provide specific light diffusion characteristics. Optionally, instead of having planar surfaces, the visor strips could be given shapes that would provide further benefits for control or distribution of light in embodiments of the present invention.
The visor strips 797 could be mounted (a) in a standard configuration per fixture, (b) could be designed and mounted at a specific angle or location according to a custom or semi-custom fixture configuration, or (c) could be adjustable by the installer or user. The mounting angle and height of the visor strips 797 , FIG. 7D , relative to the fixture could be adjusted in the factory or field. For example, in embodiments of the present invention the fixtures could be adjusted by either a mechanism that provides variable tilt, or by installation of visor strips with a mounting angle that could be specified, or by other means. Mounting height could be adjusted by shims, selection of different height visors per application, threaded adjustment, or other means.
G. Exemplary Apparatus—Light Blocking Tabs
An additional optional feature is a protruding tab 35 FIG. 9 in the vicinity of the light source which is used to block and/or reflect light which is directly emitted by the light source rather than being reflected from the reflector. The tab could be made of material which would block or reflect light, and could be more or less specular, diffusing, and/or absorbing, depending on the desired effect, position relative to the source, etc.
H. Exemplary Apparatus—Combination of Lens Types
In accordance with embodiments of the present invention, the individual optic combinations in the fixture can include a mix of refractive lenses and reflectors and may also include reflective tabs or visor strips.
I. Apparatus—Exemplary, Not Limiting
The components described above are meant to exemplify some types of possibilities. In no way should the aforementioned examples limit the scope of the invention, as they are only exemplary embodiments.
In conclusion, as illustrated through the exemplary embodiments, the present invention provides novel systems, methods and arrangements for deriving composite beams from LED or other lighting. While detailed descriptions of one or more embodiments of the invention have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Therefore, the above description should not be taken as limiting the scope of the invention.
Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations thereof.
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An apparatus, method, or system of lighting units comprising a plurality of lighting elements, such as one or more LEDs, each element having an associated optic which is individually positionable. In embodiments of the present invention, one or more optics are developed using optimization techniques that allow for lighting different target areas in an effective manner by rotating or otherwise positioning the reflectors, refractive lenses, TIR lenses, or other lens types to create a composite beam. The apparatus, method, or system of lighting herein makes it possible to widely vary the types of beams from an available fixture using a small number of inventoried optics and fixtures. In some cases, by using a combination of individual beam patterns, a small set of individual optics would be sufficient to create a majority of the typical and specialized composite beams needed to meet the needs of most lighting projects and target areas.
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CROSS REFERENCE TO RELATED APPLICATION
This application claims the priority of German Application No. 100 41 892.9 filed Aug. 25, 2000, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to a method of directly determining setting values for the application point of regulation in a regulated draw frame for slivers. The control system of the draw frame in which the extent of draft of the sliver may be set has at least one preliminary control system for changing the draft of the sliver. Based on the drafted sliver, a number of quality-characterizing measured values, such as CV values may be sensed and utilized for formulating a function whose minimum represents an optimum application point of regulation for the control of the draw frame. The optimized application point of regulation may be determined in a pre-operational test run or a setting run of the draw frame.
The application point of regulation is an important setting magnitude in a draw frame to produce slivers with a high sliver uniformity, that is, with a small CV value.
In a known system, during a pre-operational setting run, the sliver is drafted between the mid rolls and the output rolls of the draw unit and is withdrawn by calender rolls which are adjoined by a measuring device for the CV value of the drafted sliver. In the pre-operational setting run a plurality of CV values are determined which represent a quality-characterizing magnitude for the drafted sliver. Based on such measured values, a function is formulated whose minimum value corresponds to a value which promises to be the best adaptation of the regulation actual sliver. The plurality of measured values which are plotted and based on which the function is formulated, are in each instance measured for a different setting value of the regulation. Thus, for the definition of the function to be evaluated, each incremental value of an incrementally changing parameter, for example, the application point of regulation of the “electronic memory”, has to be associated with one of the measured values. For this purpose, on command, the control system sets, in the preliminary control system, an arbitrary, in most cases estimated, first value R min obtained from empirical values (for example, from a table) for the application point of regulation.
After passage of a certain sliver quantity which should be just as long that an unequivocal CV value may be calculated therefrom, a CV value designated Cv 1 is maintained fixed. This measured value taken from the measuring device is applied to a memory of the control system. Thereafter the first set application point of regulation R of the preliminary control is changed by at least one incremental magnitude. Again, the sliver is allowed to run for a certain time period until a corresponding CV 2 value is stored by the control system into the same memory range. In a similar manner a further incrementing of the application point of regulation is effected and a further measurement of a CV 3 value takes place, until a number of values is available between a minimum application point of regulation R min and a maximum application point of regulation R max . The distances between two measured values are identical to obtain a displacement-constant scanning (uniform distance of the measured values). A secured, storage-ready value as a quality value for the function becomes available only when the measurement of the CV value has occurred in a sufficiently large number of individual measurements.
It is a disadvantage of the above-outlined system that the minimum value is determined by a time-consuming search. In this process, starting from R min one proceeds in small steps along the function curve until the R max value is reached. This involves a great number of measurements in small, incremental steps which is a complex procedure.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved method of the above-outlined type from which the discussed disadvantages are eliminated and which in particular, ameliorates the determination and setting of the optimal application point of regulation at the regulating system of a draw unit and, more particularly, allows a more rapid determination of the application point of regulation. It is a further object of the invention to provide a method which also takes into consideration different, quality-characterizing magnitudes, such as different CV values.
These objects and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the method of directly determining setting values for an application point of regulation in a draw unit for drafting sliver includes the following steps: obtaining at least three measured values of a quality-characterizing magnitude, such as the CV value, of the drafted sliver; utilizing the measured values for formulating a function having a minimum constituting an optimal application point of regulation for controlling the draw unit; determining the optimal application point of regulation in a pre-operational run of the draw unit; and numerically computing a function between the quality-characterizing magnitudes and application points of regulation from the measured values.
The optimal application point of regulation (optimal dead period or delay) is determined by the draw frame itself by using the steps according to the invention. Based on the CV values of the sliver measured on line, the draw frame control system determines the optimal application point of regulation, that is, the machine optimizes itself. By the placement of as few as three measured values (R min , R max and an intermediate value R x ) it is feasible to rapidly calculate the minimum of the function and thus the optimized application point of regulation. By virtue of the fact that only few measured values need to be taken and suffice for the calculation, it is feasible in a simple manner to achieve a double time-reduction, that is, a more rapid determination of the optimized application point of regulation. The time saving further makes possible to take into consideration different, further quality-characterizing magnitudes whereby an even more accurate determination of the optimized application point of regulation is feasible.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of a regulated draw frame including a system for practicing the invention.
FIG. 1 a is a block diagram of a separate preliminary control device.
FIG. 2 is an enlarged schematic side elevational view of one part of the FIG. 1 structure, illustrating the principal drafting field with indication of the principal drafting point.
FIG. 3 is a diagram illustrating the effect of the application point of regulation on the on-line CV value.
FIG. 4 illustrates a visual representation of an automatic determination of the optimal application point of regulation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a draw frame 1 which may be, for example, an HSR model manufactured by Trutzschler GmbH & Co. KG, Monchengladbach, Germany.
The draw frame 1 includes a draw unit 2 having an upstream draw unit inlet 3 and a downstream draw unit outlet 4 . The slivers 5 are taken from non-illustrated coiler cans and are introduced into a sliver guide 6 which includes a measuring member 9 and from which they are withdrawn by calender rolls 7 , 8 .
The draw unit 2 is a 4-over-3 construction, that is, it is formed of a lower output roll I, a lower middle roll II and a lower input roll III as well as four upper rolls 11 , 12 , 13 and 14 . The draw unit 2 drafts the sliver 5 , composed of a plurality of slivers, in a preliminary and principal drafting field. The roll pairs III, 14 and II, 13 constitute the preliminary drafting field for drafting the sliver portion 5 ′ whereas the roll assembly II, 11 , 13 and the roll pair I, 12 constitute the principal drafting field for drafting the sliver portion 5 ″. The roll pair II, 13 is immediately followed by a pressure bar 30 . The drafted slivers 5 are introduced in the draw unit outlet 4 into a sliver guide 10 and are, by means of calender rolls 15 , 16 , pulled through a sliver trumpet 17 in which the slivers are combined into a single sliver 18 which is subsequently deposited in coiler cans. The direction of the sliver passing through the draw frame 1 is designated at A, and the sliver portion between the roll pairs 7 , 8 and III, 14 is designated at 5 IV .
The calender rolls 7 , 8 , the lower input roll III and the lower middle roll II which are mechanically coupled to one another, for example, by means of a toothed belt, are driven by a regulating motor 19 to which a desired rpm value may be applied. The respective upper rolls 14 and 13 are driven by the respective lower rolls by friction. The lower output roll I and the calender rolls 15 , 16 are driven by a principal motor 20 . The regulating motor 19 and the principal motor 20 each have a respective regulator 21 , 22 . Each rpm regulation occurs by means of a closed regulating circuit which includes a tachogenerator 23 connected with the motor 19 and the regulator 21 , as well as a tachogenerator 24 connected with the motor 20 and the regulator 22 .
At the draw unit inlet 3 a mass-proportionate magnitude, for example, the sliver cross section is measured by the inlet measuring organ 9 which is known, for example, from German patent document DE-A-44 04 326. At the draw unit outlet 4 the cross section of the exiting sliver 18 is sensed by an outlet measuring member 25 which is associated with the sliver trumpet 17 and which is known, for example, from German patent document DE-A-195 37 983. A central computer unit 26 (control and regulating device), for example, a microcomputer with microprocessor, transmits a setting of the desired value to the regulator 21 for the regulating motor 19 . The measured values from both measuring members 9 and 25 are transmitted to the central computer unit 26 during the drafting process. The desired rpm value for the regulating motor 19 is determined by the central computer unit 26 from the measured values sensed by the intake measuring member 9 and from the desired value for the cross section of the exiting sliver 18 . The measured values of the outlet measuring member 25 serve for monitoring the exiting sliver 18 . With the aid of such a regulating system fluctuations in the cross section of the inputted slivers 5 may be compensated for by suitable regulation of the drafting process to obtain an evening of the sliver. A monitor 27 , an interface 28 , an inputting device 29 and a memory 31 are also connected to the computer 26 .
While the preliminary control system may be integrated into the central computer unit 26 as shown in FIG. 1, according to FIG. 1 a, a separate preliminary control system 33 may be provided which is connected between the computer unit 26 and the regulator 21 . The computer unit 26 changes the application point of regulation R of the preliminary control system 33 .
The measured values, for example, thickness fluctuations of the sliver 5 , obtained from the measuring member 9 are applied to the memory 31 with a variable delay. As a result of such a delay the change in the draft of the sliver in the principal drafting field according to FIG. 2 occurs at a moment when the sliver region measured earlier by the measuring member 9 and deviating from the desired value is situated in the principal drafting point 32 . When such a sliver region reaches the principal drafting point 32 the respective measured value is called from the memory 31 .
The distance between the measuring location of the measuring member 9 and the drafting location at the principal drafting point 32 is the application point of regulation R.
The apparatus according to the invention makes possible a direct determination of the setting values for the application point of regulation R. A plurality of measured values of the sliver thickness for different lengths of the exiting sliver 5 ′″ (drafted sliver) are taken from the measuring member 25 in the sliver trumpet, and three CV values (CV 1 m , CV 10 cm , CV 3 cm ) are calculated as quality-characterizing magnitudes. In a similar manner the measuring member 9 in the sliver guide 6 takes thickness measurements of a determined length of the un-drafted sliver 5 , and from these measured magnitudes quality-characterizing CV values (CV in ) are calculated.
The determination of the CV values occurs preferably for four application points of regulation R. Expediently, in each instance two application points of regulations R are selected on the one side and two application points of regulation R are selected on the other side of the optimal application point of regulation R opt . In each instance a quality-characterizing number QK is determined by calculation from the CV values of the un-drafted sliver 5 and the drafted sliver 5 ′″. Further, a function between the numbers QK and the corresponding application points of regulation R are calculated in the computer 26 and displayed on the screen 27 (FIGS. 3 and 4 ). A polynomial of the second degree is determined from the four values of the application point of regulation R and the respective quality-characterizing numbers QK, and subsequently the minimum of the curve is calculated. The minimum point of the function corresponds to the optimum application point of regulation R opt (see FIG. 4 ). In this manner, based on the drafted sliver 5 ′″, several measured values of three different CV values and based on the un-drafted sliver 5 , several measured values of a CV value are utilized, and those CV values which correspond to one another in relation to the application point of regulation R are combined to a quality number QK. Based on several quality numbers QK a function is formulated by computation, whose minimum point corresponds to the optimum application point of regulation R opt .
During operation, in a setting run or test run, as a first step a predicted first value for the application point of regulation, for example, R −5 is set. This value is preferably an empirical value. Inputting may occur by the inputting device 29 or by calling the data from a memory. Subsequently, the following steps are taken:
The sliver quality measured on-line for each setting of an application point of regulation is determined in each instance over a sliver length of 250-300 m.
The measurements for optimizing the application point of regulation are performed on a sliver length without coiler can exchange; this may occur, for example, while the draw frame is at a standstill between the individual application points of regulation R.
The determination of the on-line measured sliver quality is effected based on the following quality values:
Output sliver quality: CV 3 cm , CV 10 cm , CV 1 m (determined, for example, by a sensor arrangement 25 at the draw frame outlet 4 which may be a SLIVER-FOCUS model manufactured by Trutzschler GmbH & Co. KG).
Input sliver quality is described by CV in , (this is performed at the sensor device 9 ).
From the above different quality values a quality-characterizing number QK is determined by the following formula:
QK =CV 3 cm +CV 10 cm +CV 1 cm −CV in
With the above quality-characterizing number a sliver quality is sufficiently determined:
QK highbad quality
QK lowgood quality.
Based on the QK equation, the natural scattering of the individual values is reduced and outlier values are not evaluated beyond what they are worth. The formation of a mean value leads to more exact predictions, and the influence of the regulation for both long and short wavelengths is taken into consideration. Even the influence of the input quality (sliver 5 ) is taken into consideration in the computation.
The QK values which are computed from the real CV values obtained during tests are utilized for developing steps 4 , 5 , 6 , 7 and 8 described below.
The course of the quality curve above the application point of regulation R is always symmetrical to the minimum value of the curve (FIG. 3 ), that is, in case of an optimum application point of regulation R=0, the CV value deterioration at −4 is of the same extent as at +4. The functional relationship is described based on the symmetry by a polynomial of the second degree.
Preferably, the region between −5 and +5 is to be considered so that the quality differences are sufficiently substantial and, at the same time, the level of the application point of regulation remains realistic.
Reductions of three to four values for the application point of regulation R yield sufficient locations of reference (four pieces):
−5 −4 −3 −1 0 1 2 3 4 5
A polynomial of second degree (symmetrical course) is determined, with the aid of numerical solution process, from the four values for the application point of regulation R and the respective QK values.
Thereafter, by means of numeric processes the minimum of the curve is determined.
Such a minimum value is the optimum application point of regulation R in the then applicable machine setting and given fiber material (FIG. 4 ).
By visual observation (monitor screen 27 ) an automatic determination of the application point of regulation may be displayed for the operator in a reproducible manner (FIG. 4 ).
A number of different CV values of different sliver length portions are compared with one another and in addition to the output quality (sliver 5 ′″), the input quality too, is taken into consideration as an important quality characteristic. Further, the principal drafting point is calculated from the minimum of a polynomial of the second degree, that is, a symmetrical course. Based on an algorithm, several different CV values are combined to a quality-characterizing number QK. From the application points of regulation R and the corresponding quality-characterizing numbers a function is constructed by approximation. The minimum is calculated from the resulting function course. The determination is effected during pre-operational test run or setting run. The optimum application point of regulation R opt is taken over prior to beginning of the regular production by the control system 26 , 33 and a consistency inquiry is performed, possibly with error reports, and the result is reproducibly shown to the operator in a graphical representation. Four quality-characterizing numbers QK are obtained for determined application points of regulation R. These four quality-characterizing-numbers are stored in a memory and based thereon a function curve is approximated. only thereafter is the minimum of the function curve calculated. For each quality- number a few meters of sliver are delivered. The quality characterizing magnitude (CV value) is determined between the delivery roll and the location of sliver deposition (output) as well as the measuring device 9 at the draw unit input 3 . The test run is performed during the charging of one coiler can. Between the four application points of regulation R (reference locations) the draw frame is stopped. The defined four application points of regulation R have different distances from one another.
The automatic optimization according to the invention of the application point of regulation has, among others, the following advantages:
Faster optimization of the application point of regulation;
Optimization is performed with economy of material;
No need to utilize laboratory equipment or Uster-testers;
CV values for the optimization are no longer distorted by effects such as coiler can deposition, climatic influences, and the like. In this manner, a better optimization result is achieved;
Realization of a “self-optimizing draw frame”;
Effective utilization of the machine control system (computer 26 );
By means of the automatic optimization the optimum application point of regulation may be found even if the data of the working memory and the data of the mechanical setting do not agree with one another; and
Knowledge transfer for performing at the manual optimization to the utilizer (operator) is dispensed with.
By virtue of the automatic determination of the application point of regulation (principal drafting point) not only the sliver uniformity but also, to the same extent, the CV values of the yarn quality may be improved. This was found in wool spinning products and PES/BW mixtures.
The invention was explained in connection with a regulated draw frame 1 . It is to be understood that it may find application in other machines which include a regulated draw unit 2 , such as a carding machine, a combing machine and the like.
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.
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A method of directly determining setting values for an application point of regulation in a draw unit for drafting sliver includes the following steps: Obtaining at least three measured values of a quality-characterizing magnitude, such as the CV value, of the drafted sliver; utilizing the measured values for formulating a function having a minimum constituting an optimal application point of regulation for controlling the draw unit; determining the optimal application point of regulation in a pre-operational run of the draw unit; and numerically computing a function between the quality-characterizing magnitudes and application points of regulation from the measured values.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention disclosed herein relates to a method and apparatus for punching holes in continuously moving board material.
2. Description of the Prior Art
Known methods and apparatuses for punching non-elongated holes in board material utilize reciprocating motion. Flat press plates having pins thereon are reciprocated to press the pins into the board while the board is held stationary, the board being moved between each press of the plate. While the holes thus produced are non-elongated, the board is not moved continuously which results in a generally slower operation when compared to a continuously moving board system. Also, a generally more complex system is required to start and stop the motion of the board and to synchronize the board and press motion in a reciprocating press system than in a continually moving board system. U.S. Pat. No. 3,538,797 issued in the name of the assignee herein, discloses a continuous system using a rotating drum with pins mounted thereon. However, the system disclosed in the aforementioned patent, while speeding up the hole punching operation by continuously moving the board, produces holes which are somewhat elongated. In many instances such elongation in the holes is considered aesthetically unsatisfactory. The invention disclosed herein provides for the continuous movement of the board and produces punched board with no or negligible elongation of the holes. Also, additional advantages are realized by the instant invention as will be apparent hereafter.
SUMMARY OF THE INVENTION
The present invention is embodied in and carried out by a method and apparatus for punching holes in continuously moving board material in which the punched holes have no or negligible elongation. The board is continuously moved in a first direction and hole punching means are moved along a first arc to contact the moving board over at least a portion of the arc, the angular speed of the hole punching means and the first speed being chosen such that the speed of the hole punching means is approximately equal to the speed of the board at least during the time that they are in contact, the hole punching means being in a predetermined orientation with respect to the board at least during the time that they are in contact. The hole punching means may be positioned in the predetermined orientation by movement thereof along a second arc.
These and other aspects of the present invention will be more apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
The invention is illustrated by way of example in the figures of the accompanying drawing in which like numerals refer to like parts and in which:
FIG. 1 diagrammatically shows an elevation view of the preferred embodiment of the invention;
FIG. 2 diagrammatically shows partly in section a side view of FIG. 1 taken along 2--2, also showing the gearing used to assist in driving the embodiment of FIG. 1;
FIG. 3 diagrammatically shows an end view of another embodiment of the invention;
FIG. 4 shows a side view of the embodiment of FIG. 3;
FIG. 5 diagrammatically shows a view of an alternative embodiment according to the present invention; and
FIG. 6 shows a detail of a portion of irregular edged plates from which hole punching pins extend.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, apparatus 10 for rotating hole punching means while maintaining the hole punching means in the same predetermined orientation relative to continuously moving board 12 is diagrammatically shown. Board 12, advantageously fiber board, is continuously moved in a first direction in a plane normal to that of the figure at a first speed. This may be accomplished by means of conveyor 14. Other apparatuses for moving board 12 will be apparent to those skilled in the art. Planet gears 16 of same diameter are positioned to mesh with sun gear 18 and are spaced equally about the circumference of sun gear 18. The shafts 20 of the planet gears 16 are rigidly secured to the respective planet gear and bearing mounted on plate 22. Shaft 24 is rigidly fixed to sun gear 18 and is restrained (not shown) from rotating except about its own axis. Shaft 24 may be restrained from rotating except about its own axis by connection to, for example, driving means (FIG. 2) as will be described more fully hereinafter. Plate 22 is free to rotate in the plane normal to the plane of board 12 about an axis which lies along shaft 24. Both shaft 24 and plate 22 are driven by means (FIG. 2) about the axis of the shaft at a sun gear to planet gear angular speed ratio of 2.25 to 1. Since the planet and sun gears mesh, rotation of the sun gear 18 about shaft 24 causes the planet gears to rotate about their respective shafts 20. The sun gear to planet gear diameter ratio is 1 to 1.25. Since plate 22 is driven to rotate about an axis along shaft 24, the planet gears rotate about the sun gear. Thus, planet gears 16 rotate about their own axes (shafts 20) as well as about the axis of sun gear 18. The sun gear and plate 22 are rotated in the same direction, shown to be clockwise in FIG. 1. This causes the planet gears to rotate about their own axes (shafts 20) in the opposite direction (counterclockwise).
Rigidly secured to each shaft 20 are respective plates 26, each having a multiplicity of pins 28 thereon. The plates are rigidly secured to the respective shafts to rotate therewith. Accordingly, as the planet gears are rotated about shafts 20, plates 26 are correspondingly rotated. System 10 is aligned so that pins 28 extend normal to the top surface of board 12. Since the planet gears themselves are simultaneously rotated about their own axes (shafts 20) and about the sun gear in opposite directions, the plates 26 always remain in the same relative attitude with respect to the board 12, the aforementioned angular sun gear to planet gear angular speed ratio of 2.25 to 1 and the aforementioned planet gear to sun gear diameter ratio of 1.25 to 1 having been chosen to accomplish this. Although these ratios are not unique to achieve the desired result, they are necessary to each other and are considered to be the most useful ratios.
In operation, boards 12 are continuously moved in a first direction in a first plane at a first speed and plates 26 with pins 28 extending therefrom are rotated and revolved in a second plane normal to the first plane simultaneously about two axes (about shaft 24 and respective shafts 20) in opposite angular directions such that the pins are always normal to the board, the respective axes being positioned such that the arc of the plates 20 about shaft 24 contacts the boards at a tangent thereto, the speed of the boards and plate along the tangent being approximately equal. As plates 26 rotate, pins 28 extending therefrom successively contact the moving boards and punch holes therein. Since the pins are moving at approximately the same speed as the boards when they are in contact, and since the pins are normal to the board during the time of contact, the punched holes have no or negligible elongation.
While sun gear 18 and plate 22 are both driven, they may be driven from a common source. Referring to FIG. 2, a drive system 30 is shown. Shaft 32 is rigidly connected to motor 34, to gear 36 and to gear 38. Operation of motor 34 rotates shaft 32 and gears 36 and 38. Gear 40 is positioned to mesh with gear 36, the gear diameter ratio (gear 36 to gear 38) being 3 to 2. Rigidly connected to gear 40 is shaft 24 which passes through and extends past gear 44 by means of bearing 46 and through plate 22 by means of aperture 42. Gear 44 is positioned to mesh with gear 38, the gear diameter ratio (gear 44 to gear 38) being 3 to 2. Gear 44 and shaft 24 rotate independent of each other by virtue of bearing 46. L-shaped brackets 48 secure gear 44 to plate 22. Plate 22 will thus rotate at the same angular speed as gear 44. Sun gear 18 is secured to the free end of shaft 24 to rotate therewith, as described hereinbefore. Shaft 24 rotates at 3/2 the speed of shaft 32 while gear 44 rotates at 2/3 the speed of shaft 32. Accordingly, shaft 24 rotates at 9/4 the speed of gear 44 for the sun gear to planet gear angular speed ratio of 2.25 to 1.
Referring to FIGS. 3 and 4, another embodiment of the invention using a chain and sprocket arrangement 50 is shown. Center sprocket 52 and planet sprockets 54 are interconnected by chain 56. Shaft 58 is rigidly connected to sprocket 52 and shafts 60 are rigidly connected to respective sprockets 54. Shafts 60 are also interconnected by connection to plate 62. Shaft 58 is stationary. Rotation of plate 62 about shaft 58 by suitable means (not shown) causes chain 56 to move along fixed sprocket 52 and rotate sprockets 54 about respective shafts 60 in the opposite direction from the direction of movement of plate 64. Shaft 58 passes through plate 62 by means of bearing 64 so that plate 62 can rotate about shaft 58. Similar bearings (not shown) are also used between plate 62 and shafts 60 to permit relative rotation between the shafts and the plate. Base plates 26 having pins 28 extending therefrom are rigidly secured to respective shafts 60. Rotation and translational movement of shafts 60 causes plates 26 to move therewith and always remain in horizontal alignment. System 50 is aligned so that pins 28 extend normal to the top surface of board 12. As plate 62 is rotated, sprockets 54 are rotated in the opposite direction. The 1:1 gearing between fixed sprocket 52 and moving sprockets 54 insures that the pins 28 remain normal to the top surface of board 12 as the plates 26 are rotated.
In operation, boards 12 are continuously moved in a first direction in a first plane at a first speed and plates 26 with pins 28 extending therefrom are moved in a second plane normal to the first plane simultaneously, rotationally about the axis of shaft 60 and translaterally about the axis of shaft 58 but in opposite angular directions such that the pins are always normal to the board, the respective axes being positioned such that the arc of the plates 62 about shaft 58 contacts the boards at a tangent thereto, the speed of the boards and plate along the tangent being approximately equal. As plates 26 rotate, pins 28 extending therefrom successively contact the moving boards and punch holes therein. Since the pins are moving at approximately the same speed as the boards when they are in contact, and since the pins are normal to the board during the time of contact, the punched holes have no or negligible elongation.
While system 50 has been shown utilizing only two base plates 64, it will be understood that the number of base plates is not limited to two. Four, six or more base plates may be utilized as long as the respective shafts thereof are equally distant from center shaft 58. In such an arrangement, the center sprocket may be offset from the planet sprockets.
FIG. 5 shows an alternative embodiment wherein a series of bars 72 carrying acoustical pins 74 are located around a driven roll 76. The bars are counter weighted to contact the surface at a parallel angle. As with the mechanically synchronized embodiment hereinbefore discussed, this permits deep, straight-in punching with a minimum resistance to withdrawal as well as a minumum of hole-pattern elongation.
The horizontal spacing between rotating base plates in all embodiments in dependent upon the physical size of the system itself, the sun gear, sprocket shaft or driven roll size and the desired depth of penetration of the pins. A spacing of only 3/8 inches is realizable. To avoid unpunched strips in the boards the base edges 70 can be made saw-toothed so that portions of each plate overlap each other as shown in FIG. 6.
The invention disclosed herein seeks to equalize the speeds of the pins and the boards during contact and to maintain the pins in a predetermined orientation (normal) to the boards during contact. Since the pins move about an arc and the boards move in a line, the speeds of each will not be precisely equal during their entire period of contact. The boards move at a linear horizontal velocity vh. The linear horizontal velocity of the pins equals the linear velocity v of the pins times the cosine of the angle (θ) that the arc of the pins forms with the horizontal (vh = v cos θ). Accordingly, when the angle formed by the arc and the horizontal is 0°, then vh = v, and the linear speeds of the pins and boards are precisely equal. However, satisfactory results with a minumum of elongation in the holes have been achieved when contact between the pins and the boards is made when the angle between the arc and the boards is less than 30°. The cosine of 30° is 0.866. Therefore, the linear speed of the pins is never less than 0.866 of the horizontal speed of the boards during the time they are in contact, while the pins are always normal to the boards during their time of contact.
While the embodiment of FIG. 1 has been illustrated with four planet gears, it is understood that fewer or more planet gears may be utilized in accordance with the invention.
The invention disclosed herein illustrates only three embodiments for equalizing the speeds of the boards and hole punching means during contact and for maintaining the hole punching menas in a predetermined orientation with respect to the boards during contact. It is intended that the claims encompass other apparatus which will be made apparent to those skilled in the art by the disclosure herein. For example, the embodiments disclosed for the purposes of illustration employ rotary motion which is smooth and relatively easy to accomplish and control. However, other motion may be employed in accordance with the invention.
The advantages of the present invention, as well as certain changes and modifications of the disclosed embodiments thereof, will be readily apparent to those skilled in the art. It is the applicants' intention to cover by their claims all those changes and modifications which could be made to the embodiments of the invention herein chosen for the purposes of the disclosure without departing from the spirit and scope of the invention.
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Method and apparatus for punching holes in continuously moving board material are disclosed. The holes may be decorative or functional and are punched so that no or negligible elongation results. The board is continuously moved in a first direction at a first speed and at least one member having pins or other projections thereon is rotated simultaneously about two axes at angular speeds such that the pins contact and punch the board during a portion of the rotation of the member while the speed of the member and the first speed are approximately equal and with the projections being in an essentially predetermined orientation to the board. Since the projections are oriented with respect to the board and are moving at approximately the same speed as the board while they contact and punch the board, there will be no or negligible elongation of the punched holes.
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